Sample records for uranium vi exposed

  1. Uranium(VI) Diffusion in Low-Permeability Subsurface Materials...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Uranium(VI) Diffusion in Low-Permeability Subsurface Materials. Uranium(VI) Diffusion in Low-Permeability Subsurface Materials. Abstract: Uranium(VI) diffusion was investigated in...

  2. Characterization of uranium(VI) in seawater

    SciTech Connect (OSTI)

    Djogic, R.; Sipos, L.; Branica, M.

    1986-09-01T23:59:59.000Z

    The physicochemical characterization of uranium(VI) in seawater is described on the basis of species distribution calculations and experiments using polarography and spectrophotometry in artificial seawater at elevated uranium concentrations. Various dissolved uranium(VI) species are identified under different conditions of pH and carbonate concentration. Below pH 4, the hydrated uranyl ion is present in the free state (forming labile complexes). Above pH 4, a stepwise coordination of uranyl by the carbonate ion occurs. The monocarbonate complex is formed in the pH range 4-5, the bicarbonate uranyl complex between 5 and 6. Above pH 8, uranium is present predominately as the tricarbonate and to a smaller extent as a trihydroxide complex. There is satisfactory agreement between our experiments and the theoretically computed distribution of uranium(VI) in seawater based on published stability constants. The experiments done at higher concentrations are justified by theoretical distributions showing that there is no great difference in species distribution between the uranium at concentrations of 10/sup -4/ and /sup -8/ mol dm/sup -3/.

  3. NUREG/CR-6911 Tests of Uranium (VI) Adsorption

    E-Print Network [OSTI]

    NUREG/CR-6911 Tests of Uranium (VI) Adsorption Models in a Field Setting U.S. Geological Survey U/CR-6911 Tests of Uranium (VI) Adsorption Models in a Field Setting Manuscript Completed: August 2006 Date observations clearly demonstrated that in aquifers where U(VI) concentrations are controlled by adsorption

  4. Effect of Grain Size on Uranium(VI) Surface Complexation Kinetics...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Grain Size on Uranium(VI) Surface Complexation Kinetics and Adsorption Additivity. Effect of Grain Size on Uranium(VI) Surface Complexation Kinetics and Adsorption Additivity....

  5. Effects of Solid-to-Solution Ratio on Uranium(VI) Adsorption and Its

    E-Print Network [OSTI]

    Roden, Eric E.

    grade uranium standard (depleted uranium). Synthetic Effects of Solid-to-Solution Ratio on Uranium(VI) Adsorption and Its Implications T A O C H E N G interacting ligands. Introduction The migration of uranium(VI), as well as other radionuclides and metal

  6. Examination of Uranium(VI) Leaching During Ligand Promoted Dissolution of Waste Tank Sludge Surrogates

    E-Print Network [OSTI]

    Powell, Brian A.

    2008-01-01T23:59:59.000Z

    U(VI) and citric acid on goethite, gibbsite, and kaolinite.on uranium(VI) adsorption to goethite-coated sand. Env. Sci.of phosphonates onto goethite. Env. Sci. Tech. 33, 3627-

  7. Thermodynamics of the Complexation of Uranium(VI) by oxalate in aqueous solution at 10-70oC

    E-Print Network [OSTI]

    Di Bernardo, Plinio

    2009-01-01T23:59:59.000Z

    O. Tochiyama in Chemical Thermodynamics of Compounds andUpdate on the Chemical Thermodynamics of Uranium, Neptunium,Thermodynamics of the Complexation of Uranium(VI) with

  8. Modeling the Removal of Uranium U(VI) from Aqueous Solutions in the

    E-Print Network [OSTI]

    include natural U deposits, mining, milling, and tailing operations and U.S. Department of Energy (DOEModeling the Removal of Uranium U(VI) from Aqueous Solutions in the Presence of Sulfate Reducing The reduction kinetics of soluble hexavalent uranium (U(VI)) to insoluble tetravalent U(IV) by both a mixed

  9. Simulation of reactive transport of uranium(VI) in groundwater with variable chemical conditions

    E-Print Network [OSTI]

    stored in poorly designed facilities or where it has been leached from U mill tailings [USDOE, 1996Simulation of reactive transport of uranium(VI) in groundwater with variable chemical conditions alluvial aquifer beneath a former U(VI) mill located near Naturita, CO, was simulated using a surface

  10. Effects of Phosphate on Uranium(VI) Adsorption to Goethite-Coated Sand

    E-Print Network [OSTI]

    Roden, Eric E.

    Effects of Phosphate on Uranium(VI) Adsorption to Goethite-Coated Sand T A O C H E N G , M A R K O natural and contaminated environments. We studied U(VI) adsorption on goethite-coated sand (to mimic of increase in U(VI) adsorption. Phosphate was strongly bound by the goethite surface in the low pH range

  11. ELECTRONIC SOLUTION SPECTRA FOR URANIUM AND NEPTUNIUM IN OXIDATION STATES (III) TO (VI) IN ANHYDROUS HYDROGEN FLUORIDE

    E-Print Network [OSTI]

    Baluka, M.

    2013-01-01T23:59:59.000Z

    III) TO (VI) IN ANHYDROUS HYDROGEN FLUORIDE M. Baluka, N.III) TO (VI) IN ANHYDROUS HYDROGEN FLUORIDE M. Baluka(t), N.solutions in anhydrous hydrogen fluoride (AHF) of uranium

  12. TREATMENT TESTS FOR EX SITU REMOVAL OF CHROMATE & NITRATE & URANIUM (VI) FROM HANFORD (100-HR-3) GROUNDWATER FINAL REPORT

    SciTech Connect (OSTI)

    BECK MA; DUNCAN JB

    1994-01-03T23:59:59.000Z

    This report describes batch and ion exchange column laboratory scale studies investigating ex situ methods to remove chromate (chromium [VI]), nitrate (NO{sub 3}{sup -}) and uranium (present as uranium [VI]) from contaminated Hanford site groundwaters. The technologies investigated include: chemical precipitation or coprecipitation to remove chromate and uranium; and anion exchange to remove chromate, uranium and nitrate. The technologies investigated were specified in the 100-HR-3 Groundwater Treatability Test Plan. The method suggested for future study is anion exchange.

  13. Standard test method for uranium in presence of plutonium by iron(II) reduction in phosphoric acid followed by chromium(VI) titration

    E-Print Network [OSTI]

    American Society for Testing and Materials. Philadelphia

    2002-01-01T23:59:59.000Z

    Standard test method for uranium in presence of plutonium by iron(II) reduction in phosphoric acid followed by chromium(VI) titration

  14. New insights into uranium (VI) sol-gel processing

    SciTech Connect (OSTI)

    King, C.M.; Thompson, M.C.; Buchanan, B.R. (Westinghouse Savannah River Co., Aiken, SC (USA)); King, R.B. (Georgia Univ., Athens, GA (USA). Dept. of Chemistry); Garber, A.R. (South Carolina Univ., Columbia, SC (USA). Dept. of Chemistry)

    1990-01-01T23:59:59.000Z

    Nuclear Magnetic Resonance (NMR) investigations on the Oak Ridge National Laboratory process for sol-gel synthesis of microspherical nuclear fuel (UO{sub 2}), has been extremely useful in sorting out the chemical mechanism in the sol-gel steps. {sup 13}C, {sup 15}N, and {sup 1}H NMR studies on the HMTA gelation agent (Hexamethylene tetramine, C{sub 6}H{sub 12}N{sub 4}) has revealed near quantitative stability of this adamantane-like compound in the sol-gel process, contrary to its historical role as an ammonia source for gelation from the worldwide technical literature. {sup 17}O NMR of uranyl (UO{sub 2}{sup ++}) hydrolysis fragments produced in colloidal sols has revealed the selective formation of a uranyl trimer, ((UO{sub 2}){sub 3}({mu}{sub 3}-O)({mu}{sub 2}-OH){sub 3}){sup +}, induced by basic hydrolysis with the HMTA gelation agent. Spectroscopic results will be presented to illustrate that trimer condensation occurs during sol-gel processing leading to layered polyanionic hydrous uranium oxides in which HMTAH{sup +} is occluded as an intercalation'' cation. Subsequent sol-gel processing of microspheres by ammonia washing results in in-situ exchange and formation of a layered hydrous ammonium uranate with a proposed structural formula of (NH{sub 4}){sub 2} ((UO{sub 2}){sub 8} O{sub 4} (OH){sub 10}) {center dot} 8H{sub 2}O. This compound is the precursor to sintered UO{sub 2} ceramic fuel. 23 refs., 10 figs.

  15. Treatment tests for ex situ removal of chromate, nitrate, and uranium (VI) from Hanford (100-HR-3) groundwater. Final report

    SciTech Connect (OSTI)

    Beck, M.A.; Duncan, J.B.

    1993-11-15T23:59:59.000Z

    This report describes batch and anion exchange column laboratory-scale studies investigating ex situ methods to remove chromate (chromium [VI]), nitrate (NO{sub 3}), and uranium (present as uranyl (uranium [VI]) carbonato anionic species) from contaminated Hanford Site groundwaters. The technologies investigated include chemical precipitation or coprecipitation to remove chromate and uranium, and anion exchange to remove chromate, uranium, and nitrate. The technologies investigated were specified in the 100-HR-3 Groundwater Treatability Test Plan (DOE-RL 1993). The goal of these tests was to determine the best method to remove selected contaminants to below the concentration of the project performance goals. The raw data and observations made during these tests can be found in the Westinghouse Hanford Company (WHC) laboratory notebooks (Beck 1992, Herting 1993). The method recommended for future study is anion exchange with Dowex 21K resin.

  16. Model-based Analysis of Mixed Uranium(VI) Reduction by Biotic and Abiotic Pathways During in Situ Bioremediation

    SciTech Connect (OSTI)

    Zhao, Jiao; Scheibe, Timothy D.; Mahadevan, Radhakrishnan

    2013-10-24T23:59:59.000Z

    Uranium bioremediation has emerged as a potential strategy of cleanup of radionuclear contamination worldwide. An integrated geochemical & microbial community model is a promising approach to predict and provide insights into the bioremediation of a complicated natural subsurface. In this study, an integrated column-scale model of uranium bioremediation was developed, taking into account long-term interactions between biotic and abiotic processes. It is also combined with a comprehensive thermodynamic analysis to track the fate and cycling of biogenic species. As compared with other bioremediation models, the model increases the resolution of the connection of microbial community to geochemistry and establishes direct quantitative correlation between overall community evolution and geochemical variation, thereby accurately predicting the community dynamics under different sedimentary conditions. The thermodynamic analysis examined a recently identified homogeneous reduction of U(VI) by Fe(II) under dynamic sedimentary conditions across time and space. It shows that the biogenic Fe(II) from Geobacter metabolism can be removed rapidly by the biogenic sulphide from sulfate reducer metabolism, hence constituting one of the reasons that make the abiotic U(VI) reduction thermodynamically infeasible in the subsurface. Further analysis indicates that much higher influent concentrations of both Fe(II) and U(VI) than normal are required to for abiotic U(VI) reduction to be thermodynamically feasible, suggesting that the abiotic reduction cannot be an alternative to the biotic reduction in the remediation of uranium contaminated groundwater.

  17. Acceleration of Microbially Mediated U(VI) Reduction at a Uranium Mill Tailings Site, Colorado Plateau

    SciTech Connect (OSTI)

    Phil Long; Todd Anderson; Aaron Peacock; Steve Heald; Yun-Juan Chang; Dick Dayvault; Derek R. Lovley; C.T. Resch; Helen Vrionis; Irene Ortiz-Bernad; D.C. White

    2004-03-17T23:59:59.000Z

    A second field-scale electron donor amendment experiment was conducted in 2003 at the Old Rifle Uranium Mill Tailings Remedial Action (UMTRA) site in Rifle, Colorado. The objective of the 2003 experiment (done in collaboration with the U.S. Department of Energy's UMTRA Groundwater Project) was to test the hypothesis that amendment of increased concentration of electron donor would result in an increased export of electron donor down gradient which in turn would create a larger zone of down-gradient U(VI) bioreduction sustained over a longer time period relative to the 2002 experiment (Anderson et al. 2003). During the first experiment (2002), {approx}3 mM acetate was amended to subsurface over a period of 3 months in a 15m by 18m by 2.5m volume comprised of 3 upgradient monitoring wells, 20 injection wells, and 15 down-gradient monitoring wells. After an initial one-month phase of metal reduction, bioavailable oxidized Fe was consumed near the injection gallery and the dominant terminal electron accepting process became sulfate reduction, rapidly consuming the injected acetate. For the 2003 experiment, we amended sufficient acetate ({approx}10 mM) to consume available sulfate and export acetate down-gradient where bioavailable oxidized Fe was still present. Data from the experiment indicate that acetate was exported further down gradient, resulting in a larger zone of microbial U(VI) reduction than for the 2002 experiment. Geohydrologic, geochemical, and microbiological data collected during the course of both experiments enable assessment of relative importance of a number of factors controlling the experimental outcomes. Companion posters by Anderson et al. and White et al. provide additional results.

  18. Sequential Extraction Method for Determination of Fe(II/III) and U(IV/ VI) in Suspensions of Iron-Bearing Phyllosilicates and Uranium

    E-Print Network [OSTI]

    Burgos, William

    (IV/VI) in clay mineral-U suspensions such that advanced spectroscopic techniques are required. Instead, we-times more Fe(II) than U(VI). INTRODUCTION Uranium contamination is a problem at many U.S. Department associated with phyllosilicate minerals is higher than the mass of iron associated with oxide minerals

  19. Complexation of Gluconate with Uranium(VI) in Acidic Solutions: Thermodynamic Study with Structural Analysis

    E-Print Network [OSTI]

    Zhang, Zhicheng

    2009-01-01T23:59:59.000Z

    uranium is approximately one order of magnitude lower than expected, suggesting that the coordination chemistry

  20. Innovative Approach to Prevent Acid Drainage from Uranium Mill Tailings Based on the Application of Na-Ferrate (VI)

    SciTech Connect (OSTI)

    Fernandes, H.M.; Reinhart, D.; Lettie, L.; Franklin, M.R. [University of Central Florida, P.O. Box. 162450, Orlando, FL, 32816-2450 (United States); Fernandes, H.M.; Franklin, M.R. [Institute of Radiation Protection and Dosimetry (IRD), Av. Salvador Allende s/n - Recreio - Rio de Janeiro - RJ - 22795-090 (Brazil); Sharma, V. [Florida Institute of Technology, 150 West University Boulevard, Melbourne, FL 32901 (United States); Daly, L.J. [Ferrate Treatment Technologies, LLC, 6432 Pine Castle Blvd. Unit 2C, Orlando, FL, 32809 (United States)

    2006-07-01T23:59:59.000Z

    The operation of uranium mining and milling plants gives rise to huge amounts of wastes from both mining and milling operations. When pyrite is present in these materials, the generation of acid drainage can take place and result in the contamination of underground and surface waters through the leaching of heavy metals and radionuclides. To solve this problem, many studies have been conducted to find cost-effective solutions to manage acid mine drainage; however, no adequate strategy to deal with sulfide-ric h wastes is currently available. Ferrate (VI) is a powerful oxidizing agent in aqueous media. Under acidic conditions, the redox potential of the Ferrate (VI) ion is the highest of any other oxidant used in wastewater treatment processes. The standard half cell reduction potential of ferrate (VI) has been determined as +2.20 V to + 0.72 V in acidic and basic solutions, respectively. Ferrate (VI) exhibits a multitude of advantageous properties, including higher reactivity and selectivity than traditional oxidant alternatives, as well as disinfectant, flocculating, and coagulant properties. Despite numerous beneficial properties in environmental applications, ferrate (VI) has remained commercially unavailable. Starting in 1953, different methods for producing a high purity, powdered ferrate (VI) product were developed. However, producing this dry, stabilized ferrate (VI) product required numerous process steps which led to excessive synthesis costs (over $20/lb) thereby preventing bulk industrial use. Recently a novel synthesis method for the production of a liquid ferrate (VI) based on hypochlorite oxidation of ferric ion in strongly alkaline solutions has been discovered (USPTO 6,790,428; September 14, 2004). This on-site synthesis process dramatically reduces manufacturing cost for the production of ferrate (VI) by utilizing common commodity feedstocks. This breakthrough means that for the first time ferrate (VI) can be an economical alternative to treating acid mining drainage generating materials. The objective of the present study was to investigate a methodology of preventing the generation of acid drainage by applying ferrate (VI) to acid generating materials prior to the disposal in impoundments or piles. Oxidizing the pyritic material in mining waste could diminish the potential for acid generation and its related environmental risks and long-term costs at disposal sites. The effectiveness of toxic metals removal from acid mine drainage by applying ferrate (VI) is also examined. Preliminary results presented in this paper show that the oxidation of pyrite by ferrate is a first-order rate reaction in Fe(VI) with a half-life of about six hours. The stability of Fe(VI) in water solutions will not influence the reaction rate in a significant manner. New low-cost production methods for making liquid ferrate on-site makes this technology a very attractive option to mitigate one of the most pressing environmental problems in the mining industry. (authors)

  1. ELECTRONIC SOLUTION SPECTRA FOR URANIUM AND NEPTUNIUM IN OXIDATION STATES (III) TO (VI) IN ANHYDROUS HYDROGEN FLUORIDE

    SciTech Connect (OSTI)

    Baluka, M.; Edelstein, N.; O'Donnell, T. A.

    1980-10-01T23:59:59.000Z

    Spectra have been recorded for solutions in anhydrous hydrogen fluoride (AHF) of uranium and neptunium in oxidation states (III) to (VI). The spectra for U(III), Np(III) and Np(IV) in AHF are very similar to those in acidified aqueous solution, but that for U(IV) suggests that the cationic species is UF{sub 2}{sup 2+}. The AHF spectra for the elements in oxidation states (V) and (VI) are not comparable with those of the formally analogous aqueous solutions, where the elements exist as well-defined dioxo-cations. However, the AHF spectra can be related to spectra in the gas phase, in the solid state or in non-aqueous solvents for each element in its appropriate oxidation state.

  2. Influence of Calcium on Microbial Reduction of Solid Phase Uranium (VI)

    SciTech Connect (OSTI)

    Liu, Chongxuan; Jeon, Byong-Hun; Zachara, John M.; Wang, Zheming

    2007-06-27T23:59:59.000Z

    The effect of calcium on microbial reduction of a solid phase U(VI), sodium boltwoodite (NaUO2SiO3OH ?1.5H2O), was evaluated in a culture of a dissimilatory metal-reducing bacterium (DMRB), Shewanella oneidensis strain MR-1. Batch experiments were performed in a non-growth bicarbonate medium with lactate as electron donor at pH 7 buffered with PIPES. Calcium increased both the rate and extent of Na-boltwoodite dissolution by increasing its solubility through the formation of a ternary aqueous calcium-uranyl-carbonate species. The ternary species, however, decreased the rates of microbial reduction of aqueous U(VI). Laser-induced fluorescence spectroscopy (LIFS) and transmission electron microscopy (TEM) revealed that microbial reduction of solid phase U(VI) is a sequentially coupled process of Na-boltwoodite dissolution, U(VI) aqueous speciation, and microbial reduction of dissolved U(VI) to U(IV) that accumulated on bacterial surfaces/periplasm. The overall rates of microbial reduction of solid phase U(VI) can be described by the coupled rates of dissolution and microbial reduction that were both influenced by calcium. The results demonstrated that dissolved U(VI) concentration during microbial reduction was a complex function of solid phase U(VI) dissolution kinetics, aqueous U(VI) speciation, and microbial activity.

  3. Kinetics of Uranium(VI) Desorption from Contaminated Sediments: Effect of Geochemical Conditions and Model Evaluation

    SciTech Connect (OSTI)

    Liu, Chongxuan; Shi, Zhenqing; Zachara, John M.

    2009-09-01T23:59:59.000Z

    Stirred-flow cell experiments were performed to investigate the kinetics of uranyl [U(VI)] desorption from a contaminated sediment collected from the Hanford 300 Area at the US Department of Energy (DOE) Hanford Site, Washington. Three influent solutions of variable pH, Ca and carbonate concentrations that affected U(VI) aqueous and surface speciation were used under dynamic flow conditions to evaluate the effect of geochemical conditions on the rate of U(VI) desorption. The measured rate of U(VI) desorption varied with solution chemical composition that evolved as a result of thermodynamic and kinetic interactions between the influent solutions and sediment. The solution chemical composition that led to a lower equilibrium U(VI) sorption to the solid phase yielded a faster desorption rate. The experimental results were used to evaluate a multi-rate, surface complexation model (SCM) that has been proposed to describe U(VI) desorption kinetics in the Hanford sediment that contained complex sorbed U(VI) species in mass transfer limited domains. The model was modified and supplemented by including multi-rate, ion exchange reactions to describe the geochemical interactions between the solutions and sediment. With the same set of model parameters, the modified model reasonably well described the evolution of major ions and the rates of U(VI) desorption under variable geochemical and flow conditions, implying that the multi-rate SCM is an effective way to describe U(VI) desorption kinetics in subsurface sediments.

  4. Microbial reduction of iron(III)-rich nontronite and uranium(VI)1 Gengxin Zhang1

    E-Print Network [OSTI]

    Burgos, William

    speciation and varied sorption affinity for sediment minerals. Poorly41 soluble U(IV) minerals and highly). Soluble U(VI) species can be43 biologically or chemically reduced to the sparingly soluble U(IV) mineral situ remediation of contaminated sites (Anderson et al., 2003; Istok et al., 2004; Wu et46 al., 2006a

  5. ORIGINAL PAPER Automated determination of uranium(VI) at ultra trace

    E-Print Network [OSTI]

    Sánchez, David

    -distribution of uranium [2]. Some of these activities have ceased, such as testing of nuclear weapons in the atmosphere, and some are continuing, for example electrical energy generation by nuclear reactors and use for a variety. Effluent discharges into the environment, use of phosphate fertilizers in agriculture, and use of by

  6. Electrode Induced Removal and Recovery of Uranium (VI) from Acidic Subsurfaces

    SciTech Connect (OSTI)

    Gregory, Kelvin [Carnegie Mellon University

    2013-08-12T23:59:59.000Z

    The overarching objective of this research is to provide an improved understanding of how aqueous geochemical conditions impact the removal of U and Tc from groundwater and how engineering design may be utilized to optimize removal of these radionuclides. Experiments were designed to address the unique conditions in Area 3 of ORNL while also providing broader insight into the geochemical effectors of the removal rates and extent for U and Tc. The specific tasks of this work were to: 1) quantify the impact of common aqueous geochemical and operational conditions on the rate and extent of U removal and recovery from water, 2) investigate the removal of Tc with polarized graphite electrode, and determine the influence of geochemical and operational conditions on Tc removal and recovery, 3) determine whether U and Tc may be treated simultaneous from Area 3 groundwater, and examine the bench-scale performance of electrode-based treatment, and 4) determine the capacity of graphite electrodes for U(VI) removal and develop a mathematical, kinetic model for the removal of U(VI) from aqueous solution. Overall the body of work suggests that an electrode-based approach for the remediation of acidic subsurface environments, such as those observed in Area 3 of ORNL may be successful for the removal for both U(VI) and Tc. Carbonaceous (graphite) electrode materials are likely to be the least costly means to maximize removal rates and efficiency by maximizing the electrode surface area.

  7. Influence of calcite on uranium(VI) reactive transport in the groundwater–river mixing zone

    SciTech Connect (OSTI)

    Ma, Rui; Liu, Chongxuan; Greskowiak, Janek; Prommer, Henning; Zachara, John M.; Zheng, Chunmiao

    2014-01-23T23:59:59.000Z

    Calcite is an important mineral that can affect uranyl reactive transport in subsurface sediments. This study investigated the distribution of calcite and its influence on uranyl adsorption and reactive transport in the groundwater-river mixing zone at US Hanford 300A, Washington State. Simulations using a 2D reactive transport model under field-relevant hydrogeochemical conditions revealed a complex distribution of calcite concentration as a result of dynamic groundwater-river interactions. The calcite concentration distribution in turn affected the spatial and temporal changes in aqueous carbonate, calcium, and pH, which subsequently influenced U(VI) mobility and discharge rates into the river. The results implied that calcite distribution and its concentration dynamics is an important consideration for field characterization, monitoring, and reactive transport prediction.

  8. Theoretical modeling of the uranium 4f XPS for U(VI) and U(IV) oxides

    SciTech Connect (OSTI)

    Bagus, Paul S.; Nelin, Constance J.; Ilton, Eugene S.

    2013-12-28T23:59:59.000Z

    X-ray photoelectron spectroscopy (XPS), and in particular the U4f level, has been widely used to elucidate the chemical state of uranium in various materials. In large part, previous experimental work has relied on comparing the U4f spectra of an unknown to some “standard” or using qualitative intuitive judgments on the expected behavior of the primary lines and satellite structures as a function of oxidation state and bonding environment. Such approaches are useful and can be sufficiently robust to make defensible claims. Nonetheless, there is no quantitative understanding of the chemistry and physics that control satellite structures or even the shape of the primary peaks. To address this issue, we used a rigorous, strictly ab initio theoretical approach to investigate the U(4f) XPS of U oxides with formal U(VI) and U(IV) oxidation states. Our theoretical studies are based on the electronic structures of embedded cluster models, where bonding between U and O is explicitly incorporated. We demonstrate that treatment of the many-body character of the cluster wavefunctions is essential to correctly model and interpret the U4f XPS. Here we definitively show that shake configurations, where an electron is transferred from a dominantly O2p bonding orbital into dominantly 5f or 6d antibonding orbitals, are indeed responsible for the major satellite features. Based on this rigorous theoretical framework, it is possible to establish quantitative relationships between features of the XPS spectra and the chemistry of the material.

  9. Complexation of Gluconate with Uranium(VI) in Acidic Solutions: Thermodynamic Study with Structural Analysis

    SciTech Connect (OSTI)

    Zhang, Zhicheng; Helms, G.; Clark, S. B.; Tian, Guoxin; Zanonato, PierLuigi; Rao, Linfeng

    2009-01-05T23:59:59.000Z

    Within the pC{sub H} range of 2.5 to 4.2, gluconate forms three uranyl complexes UO{sub 2}(GH{sub 4}){sup +}, UO{sub 2}(GH{sub 3})(aq), and UO{sub 2}(GH{sub 3})(GH{sub 4}){sup -}, through the following reactions: (1) UO{sub 2}{sup 2+} + GH{sub 4}{sup -} = UO{sub 2}(GH{sub 4}){sup +}, (2) UO{sub 2}{sup 2+} + GH{sub 4}{sup -} = UO{sub 2}(GH{sub 3})(aq) + H{sup +}, and (3) UO{sub 2}{sup 2+} + 2GH{sub 4}{sup -} = UO{sub 2}(GH{sub 3})(GH{sub 4}){sup -} + H{sup +}. Complexes were inferred from potentiometric, calorimetric, NMR, and EXAFS studies. Correspondingly, the stability constants and enthalpies were determined to be log {Beta}{sub 1} = 2.2 {+-} 0.3 and {Delta}H{sub 1} = 7.5 {+-} 1.3 kJ mol{sup -1} for reaction (1), log {Beta}{sub 2} = -(0.38 {+-} 0.05) and {Delta}H{sub 2} = 15.4 {+-} 0.3 kJ mol{sup -1} for reaction (2), and log {Beta}{sub 3} = 1.3 {+-} 0.2 and {Delta}H{sub 3} = 14.6 {+-} 0.3 kJ mol{sup -1} for reaction (3), at I = 1.0 M NaClO{sub 4} and t = 25 C. The UO{sub 2}(GH{sub 4}){sup +} complex forms through the bidentate carboxylate binding to U(VI). In the UO{sub 2}(GH{sub 3})(aq) complex, hydroxyl-deprotonated gluconate (GH{sub 3}{sup 2-}) coordinates to U(VI) through the five-membered ring chelation. For the UO{sub 2}(GH{sub 3})(GH{sub 4}){sup -} complex, multiple coordination modes are suggested. These results are discussed in the context of trivalent and pentavalent actinide complexation by gluconate.

  10. Magnetic resonance as a structural probe of a uranium (VI) sol-gel process

    SciTech Connect (OSTI)

    King, C.M.; Thompson, M.C.; Buchanan, B.R. (Westinghouse Savannah River Co., Aiken, SC (United States)); King, R.B. (Georgia Univ., Athens, GA (United States). Dept. of Chemistry); Garber, A.R. (South Carolina Univ., Columbia, SC (United States). Dept. of Chemistry)

    1989-01-01T23:59:59.000Z

    NMR investigations on the ORNL process for sol-gel synthesis of microspherical nuclear fuel (UO{sub 2}), has been useful in sorting out the chemical mechanism in the sol-gel steps. {sup 13}C, {sup 15}N, and {sup 1}H NMR studies on the HMTA gelation agent (Hexamethylene tetramine, C{sub 6}H{sub l2}N{sub 4}) has revealed near quantitative stability of this adamantane-like compound in the sol-Gel process, contrary to its historical role as an ammonia source for gelation from the worldwide technical literature. {sub 17}0 NMR of uranyl (UO{sub 2}{sup ++}) hydrolysis fragments produced in colloidal sols has revealed the selective formation of a uranyl trimer, ((UO{sub 2}){sub 3}({mu}{sub 3}-O)({mu}{sub 2}-OH){sub 3}){sup +}, induced by basic hydrolysis with the HMTA gelation agent. Spectroscopic results show that trimer condensation occurs during sol-gel processing leading to layered polyanionic hydrous uranium oxides in which HMTAH{sup +} is occluded as an intercalation'' cation. Subsequent sol-gel processing of microspheres by ammonia washing results in in-situ ion exchange and formation of a layered hydrous ammonium uranate with a proposed structural formula of (NH{sub 4}){sub 2}((UO{sub 2}){sub 8}O{sub 4}(OH){sub 10}) {center dot} 8H{sub 2}0. This compound is the precursor to sintered U0{sub 2} ceramic fuel.

  11. Magnetic resonance as a structural probe of a uranium (VI) sol-gel process

    SciTech Connect (OSTI)

    King, C.M.; Thompson, M.C.; Buchanan, B.R. [Westinghouse Savannah River Co., Aiken, SC (United States); King, R.B. [Georgia Univ., Athens, GA (United States). Dept. of Chemistry; Garber, A.R. [South Carolina Univ., Columbia, SC (United States). Dept. of Chemistry

    1989-12-31T23:59:59.000Z

    NMR investigations on the ORNL process for sol-gel synthesis of microspherical nuclear fuel (UO{sub 2}), has been useful in sorting out the chemical mechanism in the sol-gel steps. {sup 13}C, {sup 15}N, and {sup 1}H NMR studies on the HMTA gelation agent (Hexamethylene tetramine, C{sub 6}H{sub l2}N{sub 4}) has revealed near quantitative stability of this adamantane-like compound in the sol-Gel process, contrary to its historical role as an ammonia source for gelation from the worldwide technical literature. {sub 17}0 NMR of uranyl (UO{sub 2}{sup ++}) hydrolysis fragments produced in colloidal sols has revealed the selective formation of a uranyl trimer, [(UO{sub 2}){sub 3}({mu}{sub 3}-O)({mu}{sub 2}-OH){sub 3}]{sup +}, induced by basic hydrolysis with the HMTA gelation agent. Spectroscopic results show that trimer condensation occurs during sol-gel processing leading to layered polyanionic hydrous uranium oxides in which HMTAH{sup +} is occluded as an ``intercalation`` cation. Subsequent sol-gel processing of microspheres by ammonia washing results in in-situ ion exchange and formation of a layered hydrous ammonium uranate with a proposed structural formula of (NH{sub 4}){sub 2}[(UO{sub 2}){sub 8}O{sub 4}(OH){sub 10}] {center_dot} 8H{sub 2}0. This compound is the precursor to sintered U0{sub 2} ceramic fuel.

  12. Identification of simultaneous U(VI) sorption complexes and U(IV) nanoprecipitates on the magnetite (111) surface

    E-Print Network [OSTI]

    Singer, D.M.

    2013-01-01T23:59:59.000Z

    Malmström, M. E. , Removal of uranium(VI) from the aqueousMalmström, M. E. , Removal of uranium(VI) from the aqueous

  13. U(VI) sorption and reduction kinetics on the magnetite (111) surface

    E-Print Network [OSTI]

    Singer, D.M.

    2013-01-01T23:59:59.000Z

    C. ; Anderson, R. T. , Uranium removal from groundwater viaMalmström, M. E. , Removal of uranium(VI) from the aqueous

  14. Uranium Sequestration by Aluminum Phosphate Minerals in Unsaturated Soils

    SciTech Connect (OSTI)

    Jerden, James L. Jr. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439 (United States)

    2007-07-01T23:59:59.000Z

    A mineralogical and geochemical study of soils developed from the unmined Coles Hill uranium deposit (Virginia) was undertaken to determine how phosphorous influences the speciation of uranium in an oxidizing soil/saprolite system typical of the eastern United States. This paper presents mineralogical and geochemical results that identify and quantify the processes by which uranium has been sequestered in these soils. It was found that uranium is not leached from the saturated soil zone (saprolites) overlying the deposit due to the formation of a sparingly soluble uranyl phosphate mineral of the meta-autunite group. The concentration of uranium in the saprolites is approximately 1000 mg uranium per kg of saprolite. It was also found that a significant amount of uranium was retained in the unsaturated soil zone overlying uranium-rich saprolites. The uranium concentration in the unsaturated soils is approximately 200 mg uranium per kg of soil (20 times higher than uranium concentrations in similar soils adjacent to the deposit). Mineralogical evidence indicates that uranium in this zone is sequestered by a barium-strontium-calcium aluminum phosphate mineral of the crandallite group (gorceixite). This mineral is intimately inter-grown with iron and manganese oxides that also contain uranium. The amount of uranium associated with both the aluminum phosphates (as much as 1.4 weight percent) has been measured by electron microprobe micro-analyses and the geochemical conditions under which these minerals formed has been studied using thermodynamic reaction path modeling. The geochemical data and modeling results suggest the meta-autunite group minerals present in the saprolites overlying the deposit are unstable in the unsaturated zone soils overlying the deposit due to a decrease in soil pH (down to a pH of 4.5) at depths less than 5 meters below the surface. Mineralogical observations suggest that, once exposed to the unsaturated environment, the meta-autunite group minerals react to form U(VI)- bearing aluminum phosphates. (author)

  15. Sulfur isotopes as indicators of amended bacterial sulfate reduction processes influencing field scale uranium bioremediation

    E-Print Network [OSTI]

    Druhan, J.L.

    2009-01-01T23:59:59.000Z

    S. Pilot-scale in situ bioremediation of uranium in a highlyassociated with bioremediation of uranium to submicromolarassociated with Cr(VI) bioremediation. Environ. Sci.

  16. In-well sediment incubators to evaluate microbial community stability and dynamics following bioimmobilization of uranium

    E-Print Network [OSTI]

    Baldwin, B.R.

    2010-01-01T23:59:59.000Z

    D. R. (2008). Sustained removal of uranium from contaminateduranium remain poorly understood. The continued U(VI) removal

  17. A Spectroscopic Study of the effect of Ligand Complexation on the Reduction of Uranium(VI) by Anthraquinone-2,6-disulfonate (AH2DS)

    SciTech Connect (OSTI)

    Wang, Zheming; Wagnon, Ken B.; Ainsworth, Calvin C.; Liu, Chongxuan; Rosso, Kevin M.; Fredrickson, Jim K.

    2008-11-03T23:59:59.000Z

    In this project, the reduction rate of uranyl complexes with hydroxide, carbonate, EDTA, and Desferriferrioxamine B (DFB) by anthraquinone-2,6-disulfonate (AH2DS), a potential electron shuttle for microbial reduction of metal ions (Newman and Kolter 2000), is studied by stopped-flow kinetics techniques under anoxic atmosphere. The apparent reaction rates varied with ligand type, solution pH, and U(VI) concentration. For each ligand, a single largest kobs within the studied pH range was observed, suggesting the influence of pH-dependent speciation on the U(VI) reduction rate. The maximum reaction rate found in each case followed the order of OH- > CO32- > EDTA > DFB, consistent with the same trend of the thermodynamic stability of the uranyl complexes and ionic sizes of the ligands. Increasing the stability of uranyl complexes and ligand size decreased the maximum reduction rate. The pH-dependent rates were modeled using a second-order rate expression that was assumed to be dependent on a single U(VI) complex and AH2DS species. By quantitatively comparing the calculated and measured apparent rate constants as a function of pH, species AHDS3- was suggested as the primary reductant in all cases examined. Species UO2CO3(aq) , UO2HEDTA-, and (UO2)2(OH)22+ were suggested as the principal electron acceptors among the U(VI) species mixture in carbonate, EDTA, and hydroxyl systems, respectively.

  18. Remediation and Recovery of Uranium from Contaminated

    E-Print Network [OSTI]

    Lovley, Derek

    that Geobacter species can effectively remove uranium from contaminated groundwater by reducing soluble U emplaced in flow- through columns of uranium-contaminated sediments readily removed U(VI) from the groundwater, and 87% of the uranium that had been removed was recovered from the electrode surface after

  19. A study of uranium in South Texas lignite 

    E-Print Network [OSTI]

    Ilger, Wayne Arthur

    1983-01-01T23:59:59.000Z

    ) to a highly mobile uranium(VI) carbonate anion, such as (U02)(C03)2 . The carbonate anion stabilizes the uranium(VI) species. In 1955 Breger (10) proposed the formation of two uranium- carbonate complexes, sodium uranyl di- and tricarbonates... with the humic acid fract1on of 11gn1te. Others, includ1ng Breger and Moore (5, lB) propose that when a uranyl-carbonate complex encounters the slightly acid1c environment of lignite, the uranium(VI) carbonate complex is chemically altered. These investigators...

  20. Uranium immobilization and nuclear waste

    SciTech Connect (OSTI)

    Duffy, C.J.; Ogard, A.E.

    1982-02-01T23:59:59.000Z

    Considerable information useful in nuclear waste storage can be gained by studying the conditions of uranium ore deposit formation. Further information can be gained by comparing the chemistry of uranium to nuclear fission products and other radionuclides of concern to nuclear waste disposal. Redox state appears to be the most important variable in controlling uranium solubility, especially at near neutral pH, which is characteristic of most ground water. This is probably also true of neptunium, plutonium, and technetium. Further, redox conditions that immobilize uranium should immobilize these elements. The mechanisms that have produced uranium ore bodies in the Earth's crust are somewhat less clear. At the temperatures of hydrothermal uranium deposits, equilibrium models are probably adequate, aqueous uranium (VI) being reduced and precipitated by interaction with ferrous-iron-bearing oxides and silicates. In lower temperature roll-type uranium deposits, overall equilibrium may not have been achieved. The involvement of sulfate-reducing bacteria in ore-body formation has been postulated, but is uncertain. Reduced sulfur species do, however, appear to be involved in much of the low temperature uranium precipitation. Assessment of the possibility of uranium transport in natural ground water is complicated because the system is generally not in overall equilibrium. For this reason, Eh measurements are of limited value. If a ground water is to be capable of reducing uranium, it must contain ions capable of reducing uranium both thermodynamically and kinetically. At present, the best candidates are reduced sulfur species.

  1. U(VI) reduction to mononuclear U(VI) by desulfitobacterium spp.

    SciTech Connect (OSTI)

    Fletcher, K. E.; Boyanov, M. I.; Thomas, S. H.; Wu, Q.; Kemner, K. M.; Loffler, F. E. (Biosciences Division); (Georgia Inst. of Tech.)

    2010-06-15T23:59:59.000Z

    The bioreduction of U(VI) to U(IV) affects uranium mobility and fate in contaminated subsurface environments and is best understood in Gram-negative model organisms such as Geobacter and Shewanella spp. This study demonstrates that U(VI) reduction is a common trait of Gram-positive Desulfitobacterium spp. Five different Desulfitobacterium isolates reduced 100 {mu}M U(VI) to U(IV) in <10 days, whereas U(VI) remained soluble in abiotic and heat-killed controls. U(VI) reduction in live cultures was confirmed using X-ray absorption near-edge structure (XANES) analysis. Interestingly, although bioreduction of U(VI) is almost always reported to yield the uraninite mineral (UO{sub 2}), extended X-ray absorption fine structure (EXAFS) analysis demonstrated that the U(IV) produced in the Desulfitobacterium cultures was not UO{sub 2}. The EXAFS data indicated that the U(IV) product was a phase or mineral composed of mononuclear U(IV) atoms closely surrounded by light element shells. This atomic arrangement likely results from inner-sphere bonds between U(IV) and C/N/O- or P/S-containing ligands, such as carbonate or phosphate. The formation of a distinct U(IV) phase warrants further study because the characteristics of the reduced material affect uranium stability and fate in the contaminated subsurface.

  2. Microbial Reduction of Intragrain U(VI) in Contaminated Sediment

    SciTech Connect (OSTI)

    Liu, Chongxuan; Zachara, John M.; Zhong, Lirong; Heald, Steve M.; Wang, Zheming; Jeon, Byong Hun; Fredrickson, Jim K.

    2009-07-01T23:59:59.000Z

    The accessibility of precipitated, intragrain U(VI) in a contaminated sediment to microbial reduction was investigated to ascertain geochemical and microscopic transport phenomena controlling U(VI) bioavailability. The sediment was collected from the US DOE Hanford site, and contained uranyl precipitates in a form of Na-boltwoodite within the mm-sized granitic lithic fragments in the sediment. Microbial reduction was investigated in a culture of a dissimilatory metal-reducing bacterium (DMRB), Shewanella oneidensis strain MR-1, in bicarbonate solutions at pH 6.8 buffered by PIPES. Measurements of uranium concentration, speciation, and valence in aqueous and solid phases indicated that microbial reduction of intragrain U(VI) proceeded by two mechanisms: 1) sequentially coupled dissolution of intragrain uranyl precipitates, diffusion of dissolved U(VI) out of intragrain regions, and microbial reduction of dissolved U(VI); and 2) U(VI) reduction in the intragrain regions by soluble, diffusible biogenic reductants. The bioreduction rate in the first pathway was over 3 orders of magnitude slower than that in comparable aqueous solutions containing aqueous U(VI) only. The slower bioreduction rate was attributed to: 1) the release of calcium from the desorption/dissolution of calcium-containing minerals in the sediment, which subsequently altered U(VI) aqueous speciation and slowed U(VI) bioreduction and 2) alternative electron transfer pathways that reduced U(VI) in the intragrain regions and changed its dissolution and solubility behavior. The results implied that the overall rate of microbial reduction of intragrain U(VI) will be influenced by the reactive mass transfer of U(VI) and biogenic reductants within intragrain regions, and geochemical reactions controlling major ion concentrations that affect U(VI) aqueous speciation and microbial activity.

  3. Remediation of Uranium-contaminated Groundwater by Sorption onto Hydroxyapatite Derived

    E-Print Network [OSTI]

    Clement, Prabhakar

    of CFHA to remove uranium (U(VI)) from aqueous phase was investigated using both batch and column experiRemediation of Uranium-contaminated Groundwater by Sorption onto Hydroxyapatite Derived from, with maximum surface area, exhibited significant U (VI) removal efficiency. Column experiments were conducted

  4. Microbiological, Geochemical and Hydrologic Processes Controlling Uranium Mobility: An Integrated Field Scale Subsurface Research Challenge Site at Rifle, Colorado, February 2011 to January 2012

    E-Print Network [OSTI]

    Long, P.E.

    2013-01-01T23:59:59.000Z

    during in situ U(VI) Bioremediation with a Field-PortableField Scale Uranium Bioremediation. Environ. Sci. Technol.an in situ uranium bioremediation field site and its impact

  5. Determination of the Relative Amount of Fluorine in Uranium Oxyfluoride Particles using Secondary Ion Mass Spectrometry and Optical Spectroscopy

    SciTech Connect (OSTI)

    Kips, R; Kristo, M J; Hutcheon, I D; Amonette, J; Wang, Z; Johnson, T; Gerlach, D; Olsen, K B

    2009-05-29T23:59:59.000Z

    Both nuclear forensics and environmental sampling depend upon laboratory analysis of nuclear material that has often been exposed to the environment after it has been produced. It is therefore important to understand how those environmental conditions might have changed the chemical composition of the material over time, particularly for chemically sensitive compounds. In the specific case of uranium enrichment facilities, uranium-bearing particles stem from small releases of uranium hexafluoride, a highly reactive gas that hydrolyzes upon contact with moisture from the air to form uranium oxyfluoride (UO{sub 2}F{sub 2}) particles. The uranium isotopic composition of those particles is used by the International Atomic Energy Agency (IAEA) to verify whether a facility is compliant with its declarations. The present study, however, aims to demonstrate how knowledge of time-dependent changes in chemical composition, particle morphology and molecular structure can contribute to an even more reliable interpretation of the analytical results. We prepared a set of uranium oxyfluoride particles at the Institute for Reference Materials and Measurements (IRMM, European Commission, Belgium) and followed changes in their composition, morphology and structure with time to see if we could use these properties to place boundaries on the particle exposure time in the environment. Because the rate of change is affected by exposure to UV-light, humidity levels and elevated temperatures, the samples were subjected to varying conditions of those three parameters. The NanoSIMS at LLNL was found to be the optimal tool to measure the relative amount of fluorine in individual uranium oxyfluoride particles. At PNNL, cryogenic laser-induced time-resolved U(VI) fluorescence microspectroscopy (CLIFS) was used to monitor changes in the molecular structure.

  6. VI-1 PAPERS PUBLISHED

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    148030ENAS%206038.pdf. A new detection system for very low-energy protons from -delayed p-decay, A. Spiridon, Proceedings of VI European Summer School on Experimental...

  7. Technical Basis for Assessing Uranium Bioremediation Performance

    SciTech Connect (OSTI)

    PE Long; SB Yabusaki; PD Meyer; CJ Murray; AL N’Guessan

    2008-04-01T23:59:59.000Z

    In situ bioremediation of uranium holds significant promise for effective stabilization of U(VI) from groundwater at reduced cost compared to conventional pump and treat. This promise is unlikely to be realized unless researchers and practitioners successfully predict and demonstrate the long-term effectiveness of uranium bioremediation protocols. Field research to date has focused on both proof of principle and a mechanistic level of understanding. Current practice typically involves an engineering approach using proprietary amendments that focuses mainly on monitoring U(VI) concentration for a limited time period. Given the complexity of uranium biogeochemistry and uranium secondary minerals, and the lack of documented case studies, a systematic monitoring approach using multiple performance indicators is needed. This document provides an overview of uranium bioremediation, summarizes design considerations, and identifies and prioritizes field performance indicators for the application of uranium bioremediation. The performance indicators provided as part of this document are based on current biogeochemical understanding of uranium and will enable practitioners to monitor the performance of their system and make a strong case to clients, regulators, and the public that the future performance of the system can be assured and changes in performance addressed as needed. The performance indicators established by this document and the information gained by using these indicators do add to the cost of uranium bioremediation. However, they are vital to the long-term success of the application of uranium bioremediation and provide a significant assurance that regulatory goals will be met. The document also emphasizes the need for systematic development of key information from bench scale tests and pilot scales tests prior to full-scale implementation.

  8. Review The Toxicity of Depleted Uranium

    E-Print Network [OSTI]

    Wayne Briner

    Abstract: Depleted uranium (DU) is an emerging environmental pollutant that is introduced into the environment primarily by military activity. While depleted uranium is less radioactive than natural uranium, it still retains all the chemical toxicity associated with the original element. In large doses the kidney is the target organ for the acute chemical toxicity of this metal, producing potentially lethal tubular necrosis. In contrast, chronic low dose exposure to depleted uranium may not produce a clear and defined set of symptoms. Chronic low-dose, or subacute, exposure to depleted uranium alters the appearance of milestones in developing organisms. Adult animals that were exposed to depleted uranium during development display persistent alterations in behavior, even after cessation of depleted uranium exposure. Adult animals exposed to depleted uranium demonstrate altered behaviors and a variety of alterations to brain chemistry. Despite its reduced level of radioactivity evidence continues to accumulate that depleted uranium, if ingested, may pose a radiologic hazard. The current state of knowledge concerning DU is discussed.

  9. Uranium industry annual 1997

    SciTech Connect (OSTI)

    NONE

    1998-04-01T23:59:59.000Z

    This report provides statistical data on the U.S. uranium industry`s activities relating to uranium raw materials and uranium marketing.

  10. URANIUM IN ALKALINE ROCKS

    E-Print Network [OSTI]

    Murphy, M.

    2011-01-01T23:59:59.000Z

    chemical elements uranium zirconium niobium beryllium rarerare earths, niobium, zirconium, uranium, and thorium.respect, uranium and thorium are niobium in carbonatitcs.

  11. Dendritic Chelating Agents. 2. U(VI) Binding to Poly(amidoamine) and

    E-Print Network [OSTI]

    Goddard III, William A.

    fuel rods (2). While sorption has been primarily employed in nuclear waste management to treat aqueous nitric acid solutions in spent nuclear fuel processing facilities. Although SE and IX are well streams is a key compo- nent of the uranium nuclear fuel cycle (1­4). Uranyl [U(VI)] is the most stable

  12. URANIUM METAL POWDER PRODUCTION, PARTICLE DISTRIBUTION ANALYSIS, AND REACTION RATE STUDIES OF A HYDRIDE-DEHYDRIDE PROCESS

    E-Print Network [OSTI]

    Sames, William

    2011-08-08T23:59:59.000Z

    -12 plant in Oak Ridge, Tennessee for providing the depleted uranium used in this project. vi NOMENCLATURE ? Reaction Fraction ACV Atmosphere Containment Vessel AFCI Advanced Fuel Cycle Initiative FCML Fuel Cycle and Materials Laboratory...

  13. Uranium transformations in static microcosms.

    SciTech Connect (OSTI)

    Kelly, S. D.; Wu, W.; Yang, F.; Criddle, C.; Marsh, T. L.; O'Loughlin, E. J.; Ravel, B.; Watson, D.; Jardine, P. M.; Kemner, K. M.; Stanford Univ.; Michigan State Univ.; ORNL; BNL; EXAFS Analysis

    2010-01-01T23:59:59.000Z

    Elucidation of complex biogeochemical processes and their effects on speciation of U in the subsurface is critical for developing remediation strategies with an understanding of stability. We have developed static microcosms that are similar to bioreduction process studies in situ under laminar flow conditions or in sediment pores. Uranium L{sub 3}-edge X-ray absorption near-edge spectroscopy analysis with depth in the microcosms indicated that transformation of U{sup VI} to U{sup IV} occurred by at least two distinct processes. Extended X-ray absorption fine structure (EXAFS) analysis indicated that initial U{sup VI} species associated with C- and P-containing ligands were transformed to U{sup IV} in the form of uraninite and U associated with Fe-bound ligands. Microbial community analysis identified putative Fe{sup III} and sulfate reducers at two different depths in the microcosms. The slow reduction of U{sup VI} to U{sup IV} may contribute the stability of U{sup IV} within microcosms at 11 months after a decrease in bioreducing conditions due to limited electron donors.

  14. Selective elution of uranium from amidoxime polymer. I

    SciTech Connect (OSTI)

    Hirotsu, T.; Katoh, S.; Sugasaka, K.; Takai, N.; Seno, M.; Itagaki, T.

    1987-07-01T23:59:59.000Z

    The separative elution of uranium from an amidoxime polymer was examined by the column method with hydrochloric acid solutions. The amidoxime polymer was immersed in seawater for 40 d for preparation of an uranium-loaded polymer sample for the elution experiments; the metal ions adsorbed were Mg(II), Ca(II), Fe(III), Ni(II), Cu(II), and Zn(II) as well as UO/sub 2/(VI). It was found from the pH dependence of elution extent by a batch method that the order of elution pH values is Fe(III) < UO/sub 2/(VI) < Cu(II) < Ni(II) < Zn(II) < Ca(II) < Mg(II). In the elution by a column method, Mg(II), Ca(II), Zn(II), and Ni(II) were eluted completely by 0.1 M HCl and the eluate of enriched uranium was obtained by a succeeding elution with 0.5 or 1 M HCl. This eluate contained Cu(II) and Fe(III), which could be removed in the succeeding step. The elution treatment with hydrochloric acid solutions hardly affected the adsorptivity for uranium in seawater. It was suggested that the elution of uranium with hydrochloric acid solutions from amidoxime polymers is satisfactorily applicable to uranium elution in the recovery of uranium from seawater with amidoxime polymers.

  15. The role of nanopores on U(VI) sorption and redox behavior in U(VI)-contaminated subsurface sediments

    SciTech Connect (OSTI)

    Xu, Huifang; Roden, Eric E.; Kemner, Kenneth M.; Jung, Hun-Bok; Konishi, Hiromi; Boyanov, Maxim; Sun, Yubing; Mishra, Bhoopesh

    2013-10-16T23:59:59.000Z

    Most reactive surfaces in clay-dominated sediments are present within nanopores (pores of nm dimension). The behavior of geological fluids and minerals in nanopores is significantly different from those in normal non-nanoporous environments. The effect of nanopore surfaces on U(VI) sorption/desorption and reduction is likely to be significant in clay-rich subsurface environments. Our research results from both model nanopore system and natural sediments from both model system (synthetic nanopore alumina) and sediments from the ORNL Field Research Center prove that U(VI) sorption on nanopore surfaces can be greatly enhanced by nanopore confinement environments. The results from the project provide advanced mechanistic, quantitative information on the physiochemical controls on uranium sorption and redox behavior in subsurface sediments. The influence of nanopore surfaces on coupled uranium sorption/desorption and reduction processes is significant in virtually all subsurface environments, because most reactive surfaces are in fact nanopore surfaces. The results will enhance transfer of our laboratory-based research to a major field research initiative where reductive uranium immobilization is being investigated. Our results will also provide the basic science for developing in-situ colloidal barrier of nanoporous alumina in support of environmental remediation and long term stewardship of DOE sites.

  16. LABORATORY VI ELECTRICITY FROM MAGNETISM

    E-Print Network [OSTI]

    Minnesota, University of

    LABORATORY VI ELECTRICITY FROM MAGNETISM Lab VI - 1 In the previous problems you explored by electric currents. This lab will carry that investigation one step further, determining how changing magnetic fields can give rise to electric currents. This is the effect that allows the generation

  17. LABORATORY VI ELECTRICITY FROM MAGNETISM

    E-Print Network [OSTI]

    Minnesota, University of

    LABORATORY VI ELECTRICITY FROM MAGNETISM Lab VI - 1 In the previous problems you explored the magnetic field and its effect on moving charges. You also saw how electric currents could create magnetic can give rise to electric currents. This is the effect that allows the generation of electricity

  18. 2.0 GEOGRAPHIC ANALYSIS ON THE LOCATION OF URANIUM MINES

    E-Print Network [OSTI]

    2.0 GEOGRAPHIC ANALYSIS ON THE LOCATION OF URANIUM MINES With the exception of some phosphate mine areas in central and northern Florida, people are most likely to be exposed to uranium mining to understand the potential impacts and scenarios by which humans and the environment may be impacted by uranium

  19. Uranium industry annual 1996

    SciTech Connect (OSTI)

    NONE

    1997-04-01T23:59:59.000Z

    The Uranium Industry Annual 1996 (UIA 1996) provides current statistical data on the US uranium industry`s activities relating to uranium raw materials and uranium marketing. The UIA 1996 is prepared for use by the Congress, Federal and State agencies, the uranium and nuclear electric utility industries, and the public. Data on uranium raw materials activities for 1987 through 1996 including exploration activities and expenditures, EIA-estimated reserves, mine production of uranium, production of uranium concentrate, and industry employment are presented in Chapter 1. Data on uranium marketing activities for 1994 through 2006, including purchases of uranium and enrichment services, enrichment feed deliveries, uranium fuel assemblies, filled and unfilled market requirements, uranium imports and exports, and uranium inventories are shown in Chapter 2. A feature article, The Role of Thorium in Nuclear Energy, is included. 24 figs., 56 tabs.

  20. Micro-Scale Heterogeneity in Biogeochemical Uranium Cycling

    SciTech Connect (OSTI)

    Ginder-Vogel, M.; Wu, W.-M.; Kelly, S.; Criddle, C.S.; Carley, J.; Jardine, P.; Kemner, K.M.; Fendorf, S.

    2009-06-04T23:59:59.000Z

    One method for the in situ remediation of uranium contaminated subsurface environments is the removal of highly soluble U(VI) from groundwater by microbial reduction to the sparingly soluble U(IV) mineral uraninite. Success of this remediation strategy will, in part, be determined by the extent and products of microbial reduction. In heterogeneous subsurface environments, microbial processes will likely yield a combination of U(IV) and U(VI) phases distributed throughout the soil matrix. Here, we use a combination of bulk X-ray absorption spectroscopy (XAS) and micro-focused XAS and X-ray diffraction to determine uranium speciation and distribution with sediment from a pilot-scale uranium remediation project located in Oak Ridge, TN.

  1. URANIUM IN ALKALINE ROCKS

    E-Print Network [OSTI]

    Murphy, M.

    2011-01-01T23:59:59.000Z

    Greenland," in Uranium Exploration Geology, Int. AtomicMigration of Uranium and Thorium—Exploration Significance,"interesting for future uranium exploration. The c r i t e r

  2. Fingerprinting Uranium | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Fingerprinting Uranium Fingerprinting Uranium Researchers show how to use x-rays to identify mobile, stationary forms of atomic pollutant PNNL and University of North Texas...

  3. Biotransformation involved in sustained reductive removal of uranium in contaminant aquifers

    SciTech Connect (OSTI)

    Lovley, Derek R.

    2005-06-01T23:59:59.000Z

    This report summarizes progress made from August 2004 to July 2005. During this period research focused primarily on obtaining a better understanding of the factors controlling the reduction of U(VI) during in situ uranium bioremediation as well as investigating the potential for using electrodes as an alternative electron donor to promote in situ uranium reduction. Analysis of the 2003 experiment at the field study site in Rifle, CO was completed. The results demonstrated the substantial heterogeneity of the zone undergoing bioremediation, both in terms of geochemistry and microbiology. The lack of U(VI) reduction under sulfate-reducing conditions was clearly documented. The need for more detailed sampling both with time and with depth in the aquifer was demonstrated. For the first time a comparison between the composition of the microbial community in the sediments and the microbes in the corresponding groundwater was attempted. The findings from this study are important not only in further demonstrating the potential for in situ uranium bioremediation, but also for indicating how methods and sampling approaches should be improved in the future. A manuscript summarizing these findings has been accepted for publication in Applied and Environmental Microbiology. In summer of 2004 a new field experiment was conducted at the Rifle site. A novel feature of this study was much more intensive sampling in order to better define the progression of microbial processes during in situ uranium bioremediation. The results demonstrated that stimulation of in situ uranium bioremediation with added acetate was a repeatable phenomenon and that U(VI) reduction was clearly linked to the presence and activity of microorganisms in the family Geobacteraceae. A manuscript summarizing these results is in preparation. A surprising result of the field studies at the Rifle site was that although Geobacter species actively reduced U(VI) in the groundwater, removing it from solution, a high percentage of the uranium in sediments was recovered as U(VI). In order to evaluate this further, studies were conducted in which sediments from the Rifle site were incubated under strict anaerobic conditions. This permitted accurate monitoring of the uranium speciation in the sediments as well as in the groundwater over time. When acetate was added to simulate the in situ uranium bioremediation strategy, U(VI) in the groundwater was reduced with a corresponding increase in U(IV) in the sediments. However, the U(VI) in the sediments was not reduced, even after long-term incubations. The resistance of U(VI) adsorbed to sediments to microbial reduction was not previously suspected and has important implications for in situ uranium bioremediation.

  4. Uranium Industry Annual, 1992

    SciTech Connect (OSTI)

    Not Available

    1993-10-28T23:59:59.000Z

    The Uranium Industry Annual provides current statistical data on the US uranium industry for the Congress, Federal and State agencies, the uranium and electric utility industries, and the public. The feature article, ``Decommissioning of US Conventional Uranium Production Centers,`` is included. Data on uranium raw materials activities including exploration activities and expenditures, resources and reserves, mine production of uranium, production of uranium concentrate, and industry employment are presented in Chapter 1. Data on uranium marketing activities including domestic uranium purchases, commitments by utilities, procurement arrangements, uranium imports under purchase contracts and exports, deliveries to enrichment suppliers, inventories, secondary market activities, utility market requirements, and uranium for sale by domestic suppliers are presented in Chapter 2.

  5. Uranium in the oceans: Where it goes and why

    SciTech Connect (OSTI)

    Klinkhammer, G.P. (Oregon State Univ., Corvallis (United States)); Palmer, M.R. (Bristol Univ. (England))

    1991-07-01T23:59:59.000Z

    Uranium is removed from the oceans by diffusion across the sediment-water interface of organic-rich sediments. This pathway is the largest single sink in the global budget of this element. Dissolved uranium is drawn into suboxic sediments along a concentration gradient established by the precipitation of an insoluble phase which forms when U(VI) is reduced to U(IV). This transformation occurs relatively late in the diagenetic sequence, after the microbially mediated dissolution of manganese and iron oxides, and may be induced by the onset of sulfate reduction. Metallo-organics play an important role in the diagenetic behavior of this element as some uranium is released into solution when labile organics are consumed at the sediment-water interface. In contrast, the diagenesis of authigenic Fe- and Mn-oxides exerts negligible influence on the uranium diagenetic cycle. Variations in the uranium concentration of sediment with time are controlled directly by the uranium content of the source material settling from the water column, and indirectly, by the organic content of this material and sedimentation rate. Since diffusion from seawater influences dramatically the short-term burial rate of uranium, down-core distributions of dissolved and solid uranium can provide an estimate of recent sedimentation rates in rapidly accumulating sediments.

  6. New Technique for Speciation of Uranium in Sediments Following Acetate-Stimulated Bioremediation

    SciTech Connect (OSTI)

    Not Available

    2011-06-22T23:59:59.000Z

    Acetate-stimulated bioremediation is a promising new technique for sequestering toxic uranium contamination from groundwater. The speciation of uranium in sediments after such bioremediation attempts remains unknown as a result of low uranium concentration, and is important to analyzing the stability of sequestered uranium. A new technique was developed for investigating the oxidation state and local molecular structure of uranium from field site sediments using X-Ray Absorption Spectroscopy (XAS), and was implemented at the site of a former uranium mill in Rifle, CO. Glass columns filled with bioactive Rifle sediments were deployed in wells in the contaminated Rifle aquifer and amended with a hexavalent uranium (U(VI)) stock solution to increase uranium concentration while maintaining field conditions. This sediment was harvested and XAS was utilized to analyze the oxidation state and local molecular structure of the uranium in sediment samples. Extended X-Ray Absorption Fine Structure (EXAFS) data was collected and compared to known uranium spectra to determine the local molecular structure of the uranium in the sediment. Fitting was used to determine that the field site sediments did not contain uraninite (UO{sub 2}), indicating that models based on bioreduction using pure bacterial cultures are not accurate for bioremediation in the field. Stability tests on the monomeric tetravalent uranium (U(IV)) produced by bioremediation are needed in order to assess the efficacy of acetate-stimulation bioremediation.

  7. Spectroscopic Evidence of Uranium Immobilization in Acidic Wetlands by Natural Organic Matter and Plant Roots

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Li, Dien; Kaplan, Daniel I.; Chang, Hyun-Shik; Seaman, John C.; Jaffé, Peter R.; Koster van Groos, Paul; Scheckel, Kirk G.; Segre, Carlo U.; Chen, Ning; Jiang, De-Tong; et al

    2015-03-03T23:59:59.000Z

    Biogeochemistry of uranium in wetlands plays important roles in U immobilization in storage ponds of U mining and processing facilities but has not been well understood. The objective of this work was to study molecular mechanisms responsible for high U retention by Savannah River Site (SRS) wetland sediments under varying redox and acidic (pH = 2.6–5.8) conditions using U L?-edge X-ray absorption spectroscopy. Uranium in the SRS wetland sediments existed primarily as U(VI) bonded as a bidentate to carboxylic sites (U–C bond distance at ?2.88 Å), rather than phenolic or other sites of natural organic matter (NOM). In microcosms simulatingmore »the SRS wetland processes, U immobilization on roots was 2 orders of magnitude higher than on the adjacent brown or more distant white sands in which U was U(VI). Uranium on the roots were both U(IV) and U(VI), which were bonded as a bidentate to carbon, but the U(VI) may also form a U phosphate mineral. After 140 days of air exposure, all U(IV) was reoxidized to U(VI) but remained as a bidentate bonding to carbon. This study demonstrated NOM and plant roots can highly immobilize U(VI) in the SRS acidic sediments, which has significant implication for the long-term stewardship of U-contaminated wetlands.« less

  8. Nitrate Enhanced Microbial Cr(VI) Reduction-Final Report

    SciTech Connect (OSTI)

    John F. Stolz

    2011-06-15T23:59:59.000Z

    A major challenge for the bioremediation of radionuclides (i.e., uranium, technetium) and metals (i.e., Cr(VI), Hg) is the co-occurrence of nitrate as it can inhibit metal transformation. Denitrification (nitrate reduction to dinitrogen gas) is considered the most important ecological process. For many metal and metalloid reducing bacteria, however, ammonia is the end product through respiratory nitrate reduction (RNRA). The focus of this work was to determine how RNRA impacts Cr(VI) transformation. The goal was to elucidate the specific mechanism(s) that limits Cr(VI) reduction in the presence of nitrate and to use this information to develop strategies that enhance Cr(VI) reduction (and thus detoxification). Our central hypothesis is that nitrate impacts the biotransformation of metals and metalloids in three ways 1) as a competitive alternative electron acceptor (inhibiting transformation), 2) as a co-metabolite (i.e., concomitant reduction, stimulating transformation), and 3) as an inducer of specific proteins and pathways involved in oxidation/reduction reactions (stimulating transformation). We have identified three model organisms, Geobacter metallireducens (mechanism 1), Sulfurospirillum barnesii, (mechasism 2), and Desulfovibrio desulfuricans (mechanisms 3). Our specific aims were to 1) investigate the role of Cr(VI) concentration on the kinetics of both growth and reduction of nitrate, nitrite, and Cr(VI) in these three organisms; 2) develop a profile of bacterial enzymes involved in nitrate transformation (e.g., oxidoreductases) using a proteomic approach; 3) investigate the function of periplasmic nitrite reductase (Nrf) as a chromate reductase; and 4) develop a strategy to maximize microbial chromium reduction in the presence of nitrate. We found that growth on nitrate by G. metallireducens was inhibited by Cr(VI). Over 240 proteins were identified by LC/MS-MS. Redox active proteins, outer membrane heavy metal efflux proteins, and chemotaxis sensory proteins (Gmet_2478 and Gmet_1641) were up-regulated with exposure to Cr(VI). A nine-heme cytochrome C was purified that could reduce nitrite and could be oxidized by Cr(VI). For D. desulfuricans, we found that confirmed that Cr(VI) induced a prolonged lag period when Cr(VI) was reduced. Over three hundred proteins were unequivocally identified by LC/MS-MS and a significant number of down-regulated proteins for which the levels were changed >2 fold compared to control. Sulfite reductase levels were similar, however, nitrate and nitrite reductase were down-regulated. The supernatant of spent cultures was found to contain a filterable, heat stable compound that rapidly reduced Cr(VI). In addition, desulfoviridin was purified from nitrate grown cells and shown to have nitrite reductase activity that was inhibited by Cr(VI). For S. barnesii, periplasmic nitrate reductase (Nap), nitrite reductase (Nrf), and the metalloid reductase (Rar) were purified and characterized. The supernatant of spent cultures was also found to contain a filterable, heat stable compound that rapidly reduced Cr(VI) but that Rar also reduced Cr(VI). Our results from specific aims 1 through 3 indicate that for G. metallireducens, Cr(VI) inhibits nitrate respiration as it oxidizes cytochromes involved in nitrate respiration. Iron reduction is apparently not affected and the inhibitory affects of Cr(VI) may be attenuated by the addition of sufficient Fe(III) to generate Fe(II) that abiotically reduces the chromium. For S. barnesii, although the enzyme assays indicate that the components of the respiratory pathway for nitrate (e.g. Nap and Nrf) are inhibited by chromate, the organism has a mechanism to prevent this from actually occurring. Our current hypothesis is that the non-specific metalloid reductase (Rar) is providing resistance by reducing the Cr(VI). The strategy here would be to enhance its growth and metabolism in the natural setting. Lactate is a suitable electron donor for S. barnesii but other donors are possible. Although the version of the Phylochip used for monitoring the microb

  9. In situ Microbial Community Control of the Stability of Bio-Reduced Uranium

    SciTech Connect (OSTI)

    Long, Phillip E.; McKinley, James P.; White, David C.

    2006-06-01T23:59:59.000Z

    In aerobic aquifers typical of many Department of Energy (DOE) legacy waste sites, uranium is present in the oxidized U(VI) form which is soluble and thus mobile compared to U(IV). Previous work at the Old Rifle Uranium Mill Tailings Remedial Action (UMTRA) site demonstrated that biostimulation by acetate injection promoted growth of Geobacteraceae and stimulated the microbial reduction of U(VI) to less soluble U(IV) (1, 4). Despite the potential for oxidative dissolution of bio-reduced U(IV), field experiments at the Old Rifle site show that although the rate of U(VI) reduction decreases following the on-set of sulfate reduction, U(VI) reduction continues even following the cessation of acetate injection (1, 4). However, U(VI) reduction is reversible and the basis for the observed maintenance of U(VI) reduction post-stimulation is a critical but as yet unresolved issue for the application of biostimulation as a treatment technology. The continued U(VI) reduction and the maintenance of reduced U(IV) may result from many factors including U(VI) reduction by sulfate reducing bacteria (SRB), generation of H2S or FeS0.9 which serves as an oxygen sink, or the preferential sorption of U(VI) by microbial cells or biopolymers. The overall goal of the project is to develop an understanding of the mechanisms for the maintenance of bio-reduced uranium in an aerobic aquifer under field conditions following the cessation of electron donor addition.

  10. Electron Backscatter Diffraction (EBSD) Characterization of Uranium and Uranium Alloys

    SciTech Connect (OSTI)

    McCabe, Rodney J. [Los Alamos National Laboratory; Kelly, Ann Marie [Los Alamos National Laboratory; Clarke, Amy J. [Los Alamos National Laboratory; Field, Robert D. [Los Alamos National Laboratory; Wenk, H. R. [University of California, Berkeley

    2012-07-25T23:59:59.000Z

    Electron backscatter diffraction (EBSD) was used to examine the microstructures of unalloyed uranium, U-6Nb, U-10Mo, and U-0.75Ti. For unalloyed uranium, we used EBSD to examine the effects of various processes on microstructures including casting, rolling and forming, recrystallization, welding, and quasi-static and shock deformation. For U-6Nb we used EBSD to examine the microstructural evolution during shape memory loading. EBSD was used to study chemical homogenization in U-10Mo, and for U-0.75Ti, we used EBSD to study the microstructure and texture evolution during thermal cycling and deformation. The studied uranium alloys have significant microstructural and chemical differences and each of these alloys presents unique preparation challenges. Each of the alloys is prepared by a sequence of mechanical grinding and polishing followed by electropolishing with subtle differences between the alloys. U-6Nb and U-0.75Ti both have martensitic microstructures and both require special care in order to avoid mechanical polishing artifacts. Unalloyed uranium has a tendency to rapidly oxidize when exposed to air and a two-step electropolish is employed, the first step to remove the damaged surface layer resulting from the mechanical preparation and the second step to passivate the surface. All of the alloying additions provide a level of surface passivation and different one and two step electropolishes are employed to create good EBSD surfaces. Because of its low symmetry crystal structure, uranium exhibits complex deformation behavior including operation of multiple deformation twinning modes. EBSD was used to observe and quantify twinning contributions to deformation and to examine the fracture behavior. Figure 1 shows a cross section of two mating fracture surfaces in cast uranium showing the propensity of deformation twinning and intergranular fracture largely between dissimilarly oriented grains. Deformation of U-6Nb in the shape memory regime occurs by the motion of twin boundaries formed during the martensitic transformation. Deformation actually results in a coarsening of the microstructure making EBSD more practical following a limited amount of strain. Figure 2 shows the microstructure resulting from 6% compression. Casting of U-10Mo results in considerable chemical segregation as is apparent in Figure 2a. The segregation subsists through rolling and heat treatment processes as shown in Figure 2b. EBSD was used to study the effects of homogenization time and temperature on chemical heterogeneity. It was found that times and temperatures that result in a chemically homogeneous microstructure also result in a significant increase in grain size. U-0.75Ti forms an acicular martinsite as shown in Figure 4. This microstructure prevails through cycling into the higher temperature solid uranium phases.

  11. Chapter VI Conclusion and Suggestions Chapter VIChapter VIChapter VIChapter VI

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    design for low cost, short range, low data rate and dense WSN application. Because of its low-cost are presented for future works. VI.1 Conclusion This work is an attempt toward low-power mm-wave transceiver of the fabricated LNA showed that this noise model can describe the noise behaviour of the transistors with good

  12. Uranium industry annual 1998

    SciTech Connect (OSTI)

    NONE

    1999-04-22T23:59:59.000Z

    The Uranium Industry Annual 1998 (UIA 1998) provides current statistical data on the US uranium industry`s activities relating to uranium raw materials and uranium marketing. It contains data for the period 1989 through 2008 as collected on the Form EIA-858, ``Uranium Industry Annual Survey.`` Data provides a comprehensive statistical characterization of the industry`s activities for the survey year and also include some information about industry`s plans and commitments for the near-term future. Data on uranium raw materials activities for 1989 through 1998, including exploration activities and expenditures, EIA-estimated reserves, mine production of uranium, production of uranium concentrate, and industry employment, are presented in Chapter 1. Data on uranium marketing activities for 1994 through 2008, including purchases of uranium and enrichment services, enrichment feed deliveries, uranium fuel assemblies, filled and unfilled market requirements, and uranium inventories, are shown in Chapter 2. The methodology used in the 1998 survey, including data edit and analysis, is described in Appendix A. The methodologies for estimation of resources and reserves are described in Appendix B. A list of respondents to the ``Uranium Industry Annual Survey`` is provided in Appendix C. The Form EIA-858 ``Uranium Industry Annual Survey`` is shown in Appendix D. For the readers convenience, metric versions of selected tables from Chapters 1 and 2 are presented in Appendix E along with the standard conversion factors used. A glossary of technical terms is at the end of the report. 24 figs., 56 tabs.

  13. Uranium industry annual 1994

    SciTech Connect (OSTI)

    NONE

    1995-07-05T23:59:59.000Z

    The Uranium Industry Annual 1994 (UIA 1994) provides current statistical data on the US uranium industry`s activities relating to uranium raw materials and uranium marketing during that survey year. The UIA 1994 is prepared for use by the Congress, Federal and State agencies, the uranium and nuclear electric utility industries, and the public. It contains data for the 10-year period 1985 through 1994 as collected on the Form EIA-858, ``Uranium Industry Annual Survey.`` Data collected on the ``Uranium Industry Annual Survey`` (UIAS) provide a comprehensive statistical characterization of the industry`s activities for the survey year and also include some information about industry`s plans and commitments for the near-term future. Where aggregate data are presented in the UIA 1994, care has been taken to protect the confidentiality of company-specific information while still conveying accurate and complete statistical data. A feature article, ``Comparison of Uranium Mill Tailings Reclamation in the United States and Canada,`` is included in the UIA 1994. Data on uranium raw materials activities including exploration activities and expenditures, EIA-estimated resources and reserves, mine production of uranium, production of uranium concentrate, and industry employment are presented in Chapter 1. Data on uranium marketing activities, including purchases of uranium and enrichment services, and uranium inventories, enrichment feed deliveries (actual and projected), and unfilled market requirements are shown in Chapter 2.

  14. Sustained Removal of Uranium From Contaminated Groundwater Following Stimulation of Dissimilatory Metal Reduction

    SciTech Connect (OSTI)

    N'Guessan, A. Lucie; Vrionis, Helen A.; Resch, Charles T.; Long, Philip E.; Lovley, Derek R.

    2008-04-15T23:59:59.000Z

    Previous field studies on in situ bioremediation of uraniumcontaminatedgroundwaterinanaquiferinRifle, Coloradoidentified two distinct phases following the addition of acetate to stimulate microbial respiration. In phase I, Geobacter species are the predominant organisms, Fe(III) is reduced, and microbial reduction of soluble U(VI) to insoluble U(IV) removes uranium from the groundwater. In phase II, Fe(III) is depleted, sulfate is reduced, and sulfate-reducing bacteria predominate. Long-term monitoring revealed an unexpected third phase duringwhichU(VI) removal continues even after acetate additions are stopped. All three of these phases were successfully reproduced in flow-through sediment columns.When sediments from the third phase were heat sterilized, the capacity for U(VI) removal was lost. In the live sediments U(VI) removed from the groundwater was recovered as U(VI) in the sediments.This contrasts to the recovery of U(IV) in sediments resulting from the reduction of U(VI) to U(IV) during the Fe(III) reduction phase in acetate-amended sediments. Analysis of 16S rRNA gene sequences in the sediments in which U(VI) was being adsorbed indicated that members of the Firmicutes were the predominant organisms whereas no Firmicutes sequences were detected in background sediments which did not have the capacity to sorb U(VI), suggesting that the U(VI) adsorption might be due to the presence of these living organisms or at least their intact cell components. This unexpected enhanced adsorption of U(VI) onto sediments following the stimulation of microbial growth in the subsurface may potentially enhance the cost effectiveness of in situ uranium bioremediation.

  15. In Situ Microbial Community Control of the Stability of Bio-reduced Uranium

    SciTech Connect (OSTI)

    Baldwin, Brett, R.; Peacock, Aaron, D.; Resch, Charles, T.; Arntzen, Evan; Smithgall, Amanda, N.; Pfiffner, Susan; Gan, M.; McKinley, James, P.; Long, Philip, E.; White, David, C.

    2008-03-28T23:59:59.000Z

    In aerobic aquifers typical of many Department of Energy (DOE) legacy waste sites, uranium is present in the oxidized U(VI) form which is more soluble and thus more mobile. Field experiments at the Old Rifle UMTRA site have demonstrated that biostimulation by electron donor addition (acetate) promotes biological U(VI) reduction (2). However, U(VI) reduction is reversible and oxidative dissolution of precipitated U(IV) after the cessation of electron donor addition remains a critical issue for the application of biostimulation as a treatment technology. Despite the potential for oxidative dissolution, field experiments at the Old Rifle site have shown that rapid reoxidation of bio-reduced uranium does not occur and U(VI) concentrations can remain at approximately 20% of background levels for more than one year. The extent of post-amendment U(VI) removal and the maintenance of bioreduced uranium may result from many factors including U(VI) sorption to iron-containing mineral phases, generation of H2S or FeS0.9, or the preferential sorption of U(VI) by microbial cells or biopolymers, but the processes controlling the reduction and in situ reoxidation rates are not known. To investigate the role of microbial community composition in the maintenance of bioreduced uranium, in-well sediment incubators (ISIs) were developed allowing field deployment of amended and native sediments during on-going experiments at the site. Field deployment of the ISIs allows expedient interrogation of microbial community response to field environmental perturbations and varying geochemical conditions.

  16. Uranium industry annual 1995

    SciTech Connect (OSTI)

    NONE

    1996-05-01T23:59:59.000Z

    The Uranium Industry Annual 1995 (UIA 1995) provides current statistical data on the U.S. uranium industry`s activities relating to uranium raw materials and uranium marketing. The UIA 1995 is prepared for use by the Congress, Federal and State agencies, the uranium and nuclear electric utility industries, and the public. It contains data for the period 1986 through 2005 as collected on the Form EIA-858, ``Uranium Industry Annual Survey``. Data collected on the ``Uranium Industry Annual Survey`` provide a comprehensive statistical characterization of the industry`s plans and commitments for the near-term future. Where aggregate data are presented in the UIA 1995, care has been taken to protect the confidentiality of company-specific information while still conveying accurate and complete statistical data. Data on uranium raw materials activities for 1986 through 1995 including exploration activities and expenditures, EIA-estimated reserves, mine production of uranium, production of uranium concentrate, and industry employment are presented in Chapter 1. Data on uranium marketing activities for 1994 through 2005, including purchases of uranium and enrichment services, enrichment feed deliveries, uranium fuel assemblies, filled and unfilled market requirements, uranium imports and exports, and uranium inventories are shown in Chapter 2. The methodology used in the 1995 survey, including data edit and analysis, is described in Appendix A. The methodologies for estimation of resources and reserves are described in Appendix B. A list of respondents to the ``Uranium Industry Annual Survey`` is provided in Appendix C. For the reader`s convenience, metric versions of selected tables from Chapters 1 and 2 are presented in Appendix D along with the standard conversion factors used. A glossary of technical terms is at the end of the report. 14 figs., 56 tabs.

  17. Depleted Uranium Technical Brief

    E-Print Network [OSTI]

    Depleted Uranium Technical Brief United States Environmental Protection Agency Office of Air and Radiation Washington, DC 20460 EPA-402-R-06-011 December 2006 #12;#12;Depleted Uranium Technical Brief EPA of Radiation and Indoor Air Radiation Protection Division ii #12;iii #12;FOREWARD The Depleted Uranium

  18. Microbial Reductive Transformation of Phyllosilicate Fe(III) and U(VI) in Fluvial Subsurface Sediments

    SciTech Connect (OSTI)

    Lee, Ji-Hoon; Fredrickson, Jim K.; Kukkadapu, Ravi K.; Boyanov, Maxim I.; Kemner, Kenneth M.; Lin, Xueju; Kennedy, David W.; Bjornstad, Bruce N.; Konopka, Allan; Moore, Dean A.; Resch, Charles T.; Phillips, Jerry L.

    2012-04-14T23:59:59.000Z

    The microbial reduction of Fe(III) and U(VI) were investigated in shallow aquifer sediments collected from subsurface Pleistocene flood deposits near the Hanford Reach of the Columbia River in Washington State. Increases in 0.5 N HCl-extractable Fe(II) were observed in incubated sediments and 57Fe Mössbauer spectroscopy revealed that Fe(III) associated with phyllosilicates and pyroxene was reduced to Fe(II). Aqueous uranium(VI) concentrations decreased in incubated Hanford sediments with the rate and extent being greater in sediment amended with organic carbon. X-ray absorption spectroscopy of bioreduced sediments indicated that 67-77% of the U signal was U(VI), probably as an adsorbed species associated with a new or modified reactive mineral phase. Phylotypes within the Deltaproteobacteria were more common in Hanford sediments incubated with U(VI) than without and in U(VI)-free incubations, members of the Clostridiales were dominant with sulfate-reducing phylotypes more common in the sulfate-amended sediments. These results demonstrate the potential for anaerobic reduction phyllosilicate Fe(III) and sulfate in Hanford unconfined aquifer sediments and biotransformations involving reduction and adsorption leading to decreased aqueous U concentrations.

  19. Delayed neutron assay to test sorbers for uranium-from-seawater applications

    E-Print Network [OSTI]

    Nitta, Cynthia K.

    1982-01-01T23:59:59.000Z

    Delayed Fission Neutron (DFN) assay has been applied to the measurement of uranium content in sorbers exposed to natural seawater for the purpose of evaluating advanced ion exchange resins. DFN assay was found to be ...

  20. Method for converting uranium oxides to uranium metal

    DOE Patents [OSTI]

    Duerksen, Walter K. (Norris, TN)

    1988-01-01T23:59:59.000Z

    A process is described for converting scrap and waste uranium oxide to uranium metal. The uranium oxide is sequentially reduced with a suitable reducing agent to a mixture of uranium metal and oxide products. The uranium metal is then converted to uranium hydride and the uranium hydride-containing mixture is then cooled to a temperature less than -100.degree. C. in an inert liquid which renders the uranium hydride ferromagnetic. The uranium hydride is then magnetically separated from the cooled mixture. The separated uranium hydride is readily converted to uranium metal by heating in an inert atmosphere. This process is environmentally acceptable and eliminates the use of hydrogen fluoride as well as the explosive conditions encountered in the previously employed bomb-reduction processes utilized for converting uranium oxides to uranium metal.

  1. Optical Constants ofOptical Constants of Uranium Nitride Thin FilmsUranium Nitride Thin Films

    E-Print Network [OSTI]

    Hart, Gus

    Optical Constants ofOptical Constants of Uranium Nitride Thin FilmsUranium Nitride Thin FilmsDelta--Beta Scatter Plot at 220 eVBeta Scatter Plot at 220 eV #12;Why Uranium Nitride?Why Uranium Nitride? UraniumUranium, uranium,Bombard target, uranium, with argon ionswith argon ions Uranium atoms leaveUranium atoms leave

  2. Stimulating the in situ activity of Geobacter species to remove uranium from the groundwater of a uranium-contaminated aquifer

    E-Print Network [OSTI]

    Robert T. Anderson; Helen A. Vrionis; Irene Ortiz-bernad; Charles T. Resch; Philip E. Long; Richard Dayvault; Ken Karp; Sam Marutzky; Donald R. Metzler; Aaron Peacock; David C. White; Mary Lowe; Derek R. Lovley

    2003-01-01T23:59:59.000Z

    The potential for removing uranium from contaminated groundwater by stimulating the in situ activity of dissimilatory metal-reducing microorganisms was evaluated in a uranium-contaminated aquifer located in Rifle, Colo. Acetate (1 to 3 mM) was injected into the subsurface over a 3-month period via an injection gallery composed of 20 injection wells, which was installed upgradient from a series of 15 monitoring wells. U(VI) concentrations decreased in as little as 9 days after acetate injection was initiated, and within 50 days uranium had declined below the prescribed treatment level of 0.18 ?M in some of the monitoring wells. Analysis of 16S ribosomal DNA (rDNA) sequences and phospholipid fatty acid profiles demonstrated that the initial loss of uranium from the groundwater was associated with an enrichment of Geobacter species in the treatment zone. Fe(II) in the groundwater also increased during this period, suggesting that U(VI) reduction was coincident with Fe(III) reduction. As the acetate injection continued over 50 days there was a loss of sulfate from the groundwater and an accumulation of sulfide and the composition of the microbial community changed. Organisms with 16S rDNA sequences most closely related to those of sulfate reducers became predominant,

  3. Bioremediation of ground water contaminants at a uranium mill tailings site

    SciTech Connect (OSTI)

    Barton, L.L.; Nuttall, H.E.; Thomson, B.M.; Lutze, W. [Univ. of New Mexico, Albuquerque, NM (United States)

    1995-12-31T23:59:59.000Z

    Ground water contaminated with uranium from milling operations must be remediated to reduce the migration of soluble toxic compounds. At the mill tailings site near Tuba City, Arizona (USA) the approach is to employ bioremediation for in situ immobilization of uranium by bacterial reduction of uranyl, U(VI), compounds to uraninite, U(IV). In this initial phase of remediation, details are provided to indicate the magnitude of the contamination problem and to present preliminary evidence supporting the proposition that bacterial immobilization of uranium is possible. Additionally, consideration is given to contaminating cations and anions that may be at toxic levels in ground water at this uranium mill tailing site and detoxification strategies using bacteria are addressed. A model concept is employed so that results obtained at the Tuba City site could contribute to bioremediation of ground water at other uranium mill tailings sites.

  4. Stimulating the In Situ Activity of Geobacter Species to Remove Uranium from the Groundwater of a Uranium-Contaminated Aquifer

    SciTech Connect (OSTI)

    Anderson, R. T.; Vrionis, Helen A.; Ortiz-Bernad, Irene; Resch, Charles T.; Long, Philip E.; Dayvault, R. D.; Karp, Ken; Marutzky, Sammy J.; Metzler, Donald R.; Peacock, Aaron D.; White, David C.; Lowe, Mary; Lovley, Derek R.

    2003-10-01T23:59:59.000Z

    The potential for removing uranium from contaminated groundwater by stimulating the in situ activity of dissimilatory metal-reducing microorganisms was evaluated in a uranium-contaminated aquifer located in Rifle, Colo. Acetate (1 to 3 mM) was injected into the subsurface over a 3-month period via an injection gallery composed of 20 injection wells, which was installed upgradient from a series of 15 monitoring wells. U(VI) concentrations decreased in as little as 9 days after acetate injection was initiated, and within 50 days uranium had declined below the prescribed treatment level of 0.18 _M in some of the monitoring wells. Analysis of 16S ribosomal DNA (rDNA) sequences and phospholipid fatty acid profiles demonstrated that the initial loss of uranium from the groundwater was associated with an enrichment of Geobacter species in the treatment zone. Fe(II) in the groundwater also increased during this period, suggesting that U(VI) reduction was coincident with Fe(III) reduction. As the acetate injection continued over 50 days there was a loss of sulfate from the groundwater and an accumulation of sulfide and the composition of the microbial community changed. Organisms with 16S rDNA sequences most closely related to those of sulfate reducers became predominant, and Geobacter species became a minor component of the community. This apparent switch from Fe(III) reduction to sulfate reduction as the terminal electron accepting process for the oxidation of the injected acetate was associated with an increase in uranium concentration in the groundwater. These results demonstrate that in situ bioremediation of uranium-contaminated groundwater is feasible but suggest that the strategy should be optimized to better maintain long-term activity of Geobacter species.

  5. Uranium hexafluoride public risk

    SciTech Connect (OSTI)

    Fisher, D.R.; Hui, T.E.; Yurconic, M.; Johnson, J.R.

    1994-08-01T23:59:59.000Z

    The limiting value for uranium toxicity in a human being should be based on the concentration of uranium (U) in the kidneys. The threshold for nephrotoxicity appears to lie very near 3 {mu}g U per gram kidney tissue. There does not appear to be strong scientific support for any other improved estimate, either higher or lower than this, of the threshold for uranium nephrotoxicity in a human being. The value 3 {mu}g U per gram kidney is the concentration that results from a single intake of about 30 mg soluble uranium by inhalation (assuming the metabolism of a standard person). The concentration of uranium continues to increase in the kidneys after long-term, continuous (or chronic) exposure. After chronic intakes of soluble uranium by workers at the rate of 10 mg U per week, the concentration of uranium in the kidneys approaches and may even exceed the nephrotoxic limit of 3 {mu}g U per gram kidney tissue. Precise values of the kidney concentration depend on the biokinetic model and model parameters assumed for such a calculation. Since it is possible for the concentration of uranium in the kidneys to exceed 3 {mu}g per gram tissue at an intake rate of 10 mg U per week over long periods of time, we believe that the kidneys are protected from injury when intakes of soluble uranium at the rate of 10 mg U per week do not continue for more than two consecutive weeks. For long-term, continuous occupational exposure to low-level, soluble uranium, we recommend a reduced weekly intake limit of 5 mg uranium to prevent nephrotoxicity in workers. Our analysis shows that the nephrotoxic limit of 3 {mu}g U per gram kidney tissues is not exceeded after long-term, continuous uranium intake at the intake rate of 5 mg soluble uranium per week.

  6. 300 Area Uranium Stabilization Through Polyphosphate Injection: Final Report

    SciTech Connect (OSTI)

    Vermeul, Vincent R.; Bjornstad, Bruce N.; Fritz, Brad G.; Fruchter, Jonathan S.; Mackley, Rob D.; Newcomer, Darrell R.; Mendoza, Donaldo P.; Rockhold, Mark L.; Wellman, Dawn M.; Williams, Mark D.

    2009-06-30T23:59:59.000Z

    The objective of the treatability test was to evaluate the efficacy of using polyphosphate injections to treat uranium-contaminated groundwater in situ. A test site consisting of an injection well and 15 monitoring wells was installed in the 300 Area near the process trenches that had previously received uranium-bearing effluents. This report summarizes the work on the polyphosphate injection project, including bench-scale laboratory studies, a field injection test, and the subsequent analysis and interpretation of the results. Previous laboratory tests have demonstrated that when a soluble form of polyphosphate is injected into uranium-bearing saturated porous media, immobilization of uranium occurs due to formation of an insoluble uranyl phosphate, autunite [Ca(UO2)2(PO4)2•nH2O]. These tests were conducted at conditions expected for the aquifer and used Hanford soils and groundwater containing very low concentrations of uranium (10-6 M). Because autunite sequesters uranium in the oxidized form U(VI) rather than forcing reduction to U(IV), the possibility of re-oxidation and subsequent re-mobilization is negated. Extensive testing demonstrated the very low solubility and slow dissolution kinetics of autunite. In addition to autunite, excess phosphorous may result in apatite mineral formation, which provides a long-term source of treatment capacity. Phosphate arrival response data indicate that, under site conditions, the polyphosphate amendment could be effectively distributed over a relatively large lateral extent, with wells located at a radial distance of 23 m (75 ft) reaching from between 40% and 60% of the injection concentration. Given these phosphate transport characteristics, direct treatment of uranium through the formation of uranyl-phosphate mineral phases (i.e., autunite) could likely be effectively implemented at full field scale. However, formation of calcium-phosphate mineral phases using the selected three-phase approach was problematic. Although amendment arrival response data indicate some degree of overlap between the reactive species and thus potential for the formation of calcium-phosphate mineral phases (i.e., apatite formation), the efficiency of this treatment approach was relatively poor. In general, uranium performance monitoring results support the hypothesis that limited long-term treatment capacity (i.e., apatite formation) was established during the injection test. Two separate overarching issues affect the efficacy of apatite remediation for uranium sequestration within the 300 Area: 1) the efficacy of apatite for sequestering uranium under the present geochemical and hydrodynamic conditions, and 2) the formation and emplacement of apatite via polyphosphate technology. In addition, the long-term stability of uranium sequestered via apatite is dependent on the chemical speciation of uranium, surface speciation of apatite, and the mechanism of retention, which is highly susceptible to dynamic geochemical conditions. It was expected that uranium sequestration in the presence of hydroxyapatite would occur by sorption and/or surface complexation until all surface sites have been depleted, but that the high carbonate concentrations in the 300 Area would act to inhibit the transformation of sorbed uranium to chernikovite and/or autunite. Adsorption of uranium by apatite was never considered a viable approach for in situ uranium sequestration in and of itself, because by definition, this is a reversible reaction. The efficacy of uranium sequestration by apatite assumes that the adsorbed uranium would subsequently convert to autunite, or other stable uranium phases. Because this appears to not be the case in the 300 Area aquifer, even in locations near the river, apatite may have limited efficacy for the retention and long-term immobilization of uranium at the 300 Area site..

  7. Interactions of Aqueous U(VI) with Soil Minerals in Slightly Alkaline Natural Systems

    SciTech Connect (OSTI)

    Qafoku, Nik; Icenhower, Jonathan P.

    2008-12-01T23:59:59.000Z

    Uranium (U) is a common contaminant at numerous surface and subsurface sites around the world. This paper covers some important aspects of the aqueous hexavalent uranium [U(VI)] interactions with soil minerals that are present in contaminated soils and sediments. The retention of U via interactions with soil minerals has significant consequences for the prediction of its short – and long – term behavior in soils and geological systems. Studies of the nature and type of these interactions have provided the necessary evidence for assessing the geochemical behavior of U in natural systems under different physical, biogeochemical, hydrological, and reducing or oxidizing conditions. Over the last 20 years, aqueous U(VI):solid phase interactions have been studied by geochemists, soil chemists, soil mineralogists and soil microbiologists, and the progress in some areas is remarkable. Although a mechanistic description and understanding of the complex interactions involving U and soil minerals of natural systems is currently impossible, results from carefully designed and executed experiments with these materials have improved our understanding of the heterogeneous system’s behavior and U contaminant mobility and transport. There are, however, areas that need further exploration and study. Numerous research publications were reviewed in this paper to present important findings coming out of the research, to reveal the current level of the understanding of the U(VI) interactions with soil minerals, and to provide ideas for future needs and research directions.

  8. Title VI | Department of Energy

    Energy Savers [EERE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directed off Energy.gov. Are you sure you wantJoin us for|Idahothe New Funding Constructs forofDOETipsVI

  9. In Situ Community Control of the Stability of Bioreduced Uranium

    SciTech Connect (OSTI)

    White, David C.

    2006-06-01T23:59:59.000Z

    The overall objective of this research is to understand the mechanisms for maintenance of bio-reduced uranium in an aerobic to microaerophylic aquifer under actual field conditions after electron donor addition for biostimulation has ended. Primary Objectives: (1) Determine the relative importance of microbial communities and/or chemical and physical environments mediating uranium reduction/oxidation after cessation of donor addition in an aerobic aquifer. (2) Determine, after cessation of donor addition, the linkages between microbial functions and abiotic processes mediating. Initial Hypotheses: (1) The typical bio-reduced subsurface environments that maintain U(VI) reduction rates after biostimulation contain limited amounts of oxidized iron on mineral surfaces. Therefore, the non sulfate-reducing dissimilatory iron reducing bacteria will move to more conducive areas or be out-competed by more versatile microbes. (2) Microbes capable of sulfate reduction play an important role in the post-treatment maintenance of bio-reduced uranium because these bacteria either directly reduce U(VI) or generate H2S, and/or FeS0.9 which act as oxygen sinks maintaining U(IV) in a reduced state. (3) The presence of bioprecipitated amorphous FeS0.9 in sediments will maintain low U(IV) reoxidation rates under conditions of low biomass, but FeS0.9 by itself is not sufficient to remove U(VI) from groundwater by abiotic reduction. FIELD SCALE EXPERIMENTS: Field-scale electron donor amendment experiments were conducted in 2002, 2003, and 2004 at the Old Rifle Uranium Mill Tailings Remedial Action (UMTRA) site in Rifle, Colorado.

  10. Uranium Mill Tailings Management

    SciTech Connect (OSTI)

    Nelson, J.D.

    1982-01-01T23:59:59.000Z

    This book presents the papers given at the Fifth Symposium on Uranium Mill Tailings Management. Advances made with regard to uranium mill tailings management, environmental effects, regulations, and reclamation are reviewed. Topics considered include tailings management and design (e.g., the Uranium Mill Tailings Remedial Action Project, environmental standards for uranium mill tailings disposal), surface stabilization (e.g., the long-term stability of tailings, long-term rock durability), radiological aspects (e.g. the radioactive composition of airborne particulates), contaminant migration (e.g., chemical transport beneath a uranium mill tailings pile, the interaction of acidic leachate with soils), radon control and covers (e.g., radon emanation characteristics, designing surface covers for inactive uranium mill tailings), and seepage and liners (e.g., hydrologic observations, liner requirements).

  11. Process for continuous production of metallic uranium and uranium alloys

    DOE Patents [OSTI]

    Hayden, H.W. Jr.; Horton, J.A.; Elliott, G.R.B.

    1995-06-06T23:59:59.000Z

    A method is described for forming metallic uranium, or a uranium alloy, from uranium oxide in a manner which substantially eliminates the formation of uranium-containing wastes. A source of uranium dioxide is first provided, for example, by reducing uranium trioxide (UO{sub 3}), or any other substantially stable uranium oxide, to form the uranium dioxide (UO{sub 2}). This uranium dioxide is then chlorinated to form uranium tetrachloride (UCl{sub 4}), and the uranium tetrachloride is then reduced to metallic uranium by reacting the uranium chloride with a metal which will form the chloride of the metal. This last step may be carried out in the presence of another metal capable of forming one or more alloys with metallic uranium to thereby lower the melting point of the reduced uranium product. The metal chloride formed during the uranium tetrachloride reduction step may then be reduced in an electrolysis cell to recover and recycle the metal back to the uranium tetrachloride reduction operation and the chlorine gas back to the uranium dioxide chlorination operation. 4 figs.

  12. Process for continuous production of metallic uranium and uranium alloys

    DOE Patents [OSTI]

    Hayden, Jr., Howard W. (Oakridge, TN); Horton, James A. (Livermore, CA); Elliott, Guy R. B. (Los Alamos, NM)

    1995-01-01T23:59:59.000Z

    A method is described for forming metallic uranium, or a uranium alloy, from uranium oxide in a manner which substantially eliminates the formation of uranium-containing wastes. A source of uranium dioxide is first provided, for example, by reducing uranium trioxide (UO.sub.3), or any other substantially stable uranium oxide, to form the uranium dioxide (UO.sub.2). This uranium dioxide is then chlorinated to form uranium tetrachloride (UCl.sub.4), and the uranium tetrachloride is then reduced to metallic uranium by reacting the uranium chloride with a metal which will form the chloride of the metal. This last step may be carried out in the presence of another metal capable of forming one or more alloys with metallic uranium to thereby lower the melting point of the reduced uranium product. The metal chloride formed during the uranium tetrachloride reduction step may then be reduced in an electrolysis cell to recover and recycle the metal back to the uranium tetrachloride reduction operation and the chlorine gas back to the uranium dioxide chlorination operation.

  13. Sediment studies of the biological factors controlling the reduction of U(VI).

    SciTech Connect (OSTI)

    Lovley, derek, R.

    2004-08-04T23:59:59.000Z

    Studies were conducted primarily with sediments, both in laboratory incubations and in a field experiment, with supporting studies with pure cultures. To our knowledge the sediment studies were the first on microbial U(VI) reduction in actual uranium-contaminated subsurface sediments, under conditions that mimic those found in situ. Important findings included: (1) U(VI) reduction is a biotic process in subsurface sediments. (2) U(VI) reduction can be stimulated most effectively with the addition of acetate. Although it had been speculated that microbial U(VI) reduction might be capable of this type of environmental remediation ever since the discovery of microbial U(VI) reduction, this had not been previously demonstrated under environmentally relevant conditions. (3) U(VI) is reduced concurrently with Fe(III) and prior to sulfate reduction. U(VI) and Fe(III) reduction proceeded concurrently, accompanied by a dramatic enrichment in organisms in the Geobacteraceae. Sulfate-reducing microorganisms do not appear to be important components of the microbial community reducing U(VI) in these subsurface sediments. (4) Nitrate has important influences on U(VI) reduction. Nitrate inhibits the reduction of metals until nitrate is depleted. Fe(III)-reducing microorganisms such as Geobacter metallireducens and Desulfitobacterium species can oxidize Fe(II) with the reduction of nitrate which is an important consideration because our previous studies have demonstrated that freshly precipitated Fe(III) oxides can reoxidize U(IV) to U(VI). The discovery that G. metallireducens can ''run backwards'' and oxidize U(IV) when nitrate is present reveals another mechanism preventing precipitation of U(IV) in the presence of nitrate as well as potential novel strategy for removing uranium from the subsurface after a site has been remediated. (5) Importance of understanding Fe(III) forms available for microbial reduction. Fe(III) is orders of magnitude more abundant than U(VI) as an electron acceptor to support microbial growth. It was demonstrated that poorly crystalline Fe(III) oxides and structural Fe(III) in clays are the predominant forms of microbially reducible Fe(III). Such findings are important for the development of models of Fe(III) reduction in similar aquifer environments, such as those found at many UMTRA sites. (6) Mechanisms for Fe(III) oxide reduction. It was discovered that phylogenetically distinct Fe(III) reducer have different strategies for reducing Fe(III) and the fact that Geobacter species must directly contact Fe(III) in order to reduce it may help explain its predominance over other Fe(III) reducers in the subsurface. (7) Transfer of laboratory results to the field. Results from laboratory studies were used to design a field experiment in which U(VI) reduction was successfully precipitated from the contaminated water with the injection of acetate.

  14. Microbial Community Changes in Response to Ethanol or Methanol Amendments for U(VI) Reduction

    SciTech Connect (OSTI)

    Vishnivetskaya, Tatiana A [ORNL; Brandt, Craig C [ORNL; Madden, Andrew [University of Oklahoma, Norman; Drake, Meghan M [ORNL; Kostka, Joel [Florida State University; Akob, Denise M. [Florida State University; Kusel, Kirsten [Friedrich Schiller University Jena, Jena Germany; Palumbo, Anthony Vito [ORNL

    2010-01-01T23:59:59.000Z

    Microbial community responses to ethanol, methanol and methanol + humics amendments in relationship to uranium bioremediation were studied in laboratory microcosm experiments using sediments and ground water from a uranium-contaminated site in Oak Ridge, Tennessee. Ethanol addition always resulted in uranium reduction at rate of 0.8-1.0 mol l-1 d-1 while methanol addition did so occasionally at rate 0.95 mol l-1 d-1. The type of carbon source added, the duration of incubation, and the sampling site influenced the bacterial community structure upon incubation. Analysis of 16S rRNA gene clone libraries indicated (1) bacterial communities found in ethanol- and methanol-amended samples with U(VI) reduction were similar due to presence of -Proteobacteria, and -Proteobacteria (members of the families Burkholderiaceae, Comamonadaceae, Oxalobacteraceae, and Rhodocyclaceae); (2) methanol-amended samples without U(VI) reduction exhibited the lowest diversity and the bacterial community contained 69.2-92.8% of the family Methylophilaceae; and (3) the addition of humics resulted in an increase of phylogenetic diversity of -Proteobacteria (Rodoferax, Polaromonas, Janthinobacterium, Methylophilales, unclassified) and Firmicutes (Desulfosporosinus, Clostridium).

  15. Preparation of uranium compounds

    DOE Patents [OSTI]

    Kiplinger, Jaqueline L; Montreal, Marisa J; Thomson, Robert K; Cantat, Thibault; Travia, Nicholas E

    2013-02-19T23:59:59.000Z

    UI.sub.3(1,4-dioxane).sub.1.5 and UI.sub.4(1,4-dioxane).sub.2, were synthesized in high yield by reacting turnings of elemental uranium with iodine dissolved in 1,4-dioxane under mild conditions. These molecular compounds of uranium are thermally stable and excellent precursor materials for synthesizing other molecular compounds of uranium including alkoxide, amide, organometallic, and halide compounds.

  16. Multiple Mechanisms of Uranium Immobilization by Cellulomonas sp. strain ES6

    SciTech Connect (OSTI)

    Sivaswamy, Vaideeswaran; Brent Peyton; Viamajala, Sridhar; Robin Gerlach; William Apel; Rajesh Sani; Alice Dohnalkova; Thomas Borch

    2011-02-01T23:59:59.000Z

    Removal of hexavalent uranium (U(VI)) from aqueous solution was studied using a Gram-positive facultative anaerobe, Cellulomonas sp. strain ES6, under anaerobic, non growth conditions in bicarbonate and PIPES buffers. Inorganic phosphate was released by cells during the experiments providing ligands for formation of insoluble U(VI) phosphates. Phosphate release was most probably the result of anaerobic hydrolysis of intracellular polyphosphates accumulated by ES6 during aerobic growth. Microbial reduction of U(VI) to U(IV) was also observed. However, the relative magnitudes of U(VI) removal by abiotic (phosphate-based) precipitation and microbial reduction depended on the buffer chemistry. In bicarbonate buffer, X-ray absorption near edge structure (XANES) analysis showed U precipitates containing nearly equal fractions of U(IV) and U(VI), whereas in PIPES buffer, U precipitates consisted primarily of U(VI). Mass balance calculations for U and P corroborate these observations. High-resolution transmission electron microscopy (HR42TEM) and energy dispersive X-ray spectroscopy (EDS) showed both extracellular and intracellular accumulation of U solids. The U(VI)-phosphate precipitates, confirmed by EDS as containing U and P in equimolar concentrations, had nanometer sized lath structure. When anthraquinone-2,6-disulfonate (AQDS), a known electron shuttle, was added to the experimental reactors, U reduction became the dominant removal mechanism, in contrast to primarily phosphate-mediated precipitation observed in the absence of AQDS. Uranium immobilization by abiotic precipitation or microbial reduction has been extensively reported; however, present work suggests that strain ES6 can remove U(VI) from solution simultaneously through precipitation with phosphate ligands and microbial reduction, depending on the environmental conditions. Cellulomonadaceae are environmentally relevant subsurface bacteria and here, for the first time, t 52 he presence of multiple U immobilization mechanisms within one organism is reported using Cellulomonas sp. strain ES6.

  17. LABORATORY VI ENERGY AND THERMAL PROCESSES

    E-Print Network [OSTI]

    Minnesota, University of

    LABORATORY VI ENERGY AND THERMAL PROCESSES Lab VI - 1 The change of the internal energy of a system temperature. In this lab you will concentrate on quantifying the changes in internal energy within the framework of conservation of energy. In the problems of this lab, you will master the relation

  18. Diffusive parameters of tritiated water and uranium in chalk

    SciTech Connect (OSTI)

    Descostes, M. [CEA, DEN/DANS/DPC/SECR/Laboratory of Radionuclides Migration Measurements and Modelling, F-91191 Gif-sur-Yvette, (France); UMR 8587 CEA, Universite d'Evry, CNRS, (France); Pili, E. [CEA, DAM, DIF, F-91297 Arpajon, (France); Institut de Physique du Globe, Sorbonne Paris Cite, 1 rue Jussieu, 75238 Paris cedex 05, (France); Felix, O.; Frasca, B.; Radwan, J.; Juery, A. [CEA, DEN/DANS/DPC/SECR/Laboratory of Radionuclides Migration Measurements and Modelling, F-91191 Gif-sur-Yvette, (France)

    2012-07-15T23:59:59.000Z

    The Cretaceous Chalk of North-western Europe exhibits a double porosity (matrix and fracture) providing pathways for both slow and rapid flow of water. The present study aims at understanding and predicting the contaminant transfer properties through a significant section of this formation, with a particular emphasis on diffusion. This requires to study the nature of porosity and to perform diffusion experiments in representative samples using uranium and tritiated water (HTO), respectively taken as a reactive tracer and an inert one. The diffusive parameters, i.e. the accessible porosity and the effective diffusion coefficient were determined. Additional information was obtained with mercury porosimetry, gravimetric water content, textural and mineralogical characterization. The diffusion tests performed with HTO appear to be the best method to measure the total accessible porosity in any type of porous media, especially those having large pore size distributions. Our study demonstrates that classical gravimetric water content measurements are not sensitive to the reduction in pore size as opposed to HTO diffusion tests because capillary water is not extracted by conventional gravimetric method but can still be probed by diffusion experiments. We found effective diffusion coefficients D{sub e}(U(VI)) near 4 x 10{sup -10} m{sup 2}s{sup -1}). The slower migration of U(VI) compared to HTO indicates sorption, with R{sub d}(U(VI)) from 100 to 360 mL g{sup -1}. These values are one order of magnitude larger than other determinations of the U(VI) sorption coefficient because only the matrix porosity is concerned here. The migration of U(VI) in chalk is only limited by sorption on ancillary Fe-Pb-bearing minerals. Transport of HTO and U(VI) is independent of the porosity distribution. Uranium diffusion in the chalk matrix porosity is fast enough to allow the total invasion of the pore space within characteristic time scales of the order of 1000 years. This results in a partitioning of uranium velocities in fracture flow and matrix flow proportionally to the respective fracture and matrix porosities. (authors)

  19. Determining Individual Mineral Contributions To U(VI) Adsorption...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Individual Mineral Contributions To U(VI) Adsorption In A Contaminated Aquifer Sediment: A Fluorescence Spectroscopy Determining Individual Mineral Contributions To U(VI)...

  20. CHARACTERIZATION OF URANIUM, URANIUM OXIDE AND SILICON MULTILAYER THIN FILMS

    E-Print Network [OSTI]

    Hart, Gus

    CHARACTERIZATION OF URANIUM, URANIUM OXIDE AND SILICON MULTILAYER THIN FILMS by David T. Oliphant. Woolley Dean, College of Physical and Mathematical Sciences #12;ABSTRACT CHARACTERIZATION OF URANIUM, URANIUM OXIDE AND SILICON MULTILAYER THIN FILMS David T. Oliphant Department of Physics and Astronomy

  1. Uranium dioxide electrolysis

    DOE Patents [OSTI]

    Willit, James L. (Batavia, IL); Ackerman, John P. (Prescott, AZ); Williamson, Mark A. (Naperville, IL)

    2009-12-29T23:59:59.000Z

    This is a single stage process for treating spent nuclear fuel from light water reactors. The spent nuclear fuel, uranium oxide, UO.sub.2, is added to a solution of UCl.sub.4 dissolved in molten LiCl. A carbon anode and a metallic cathode is positioned in the molten salt bath. A power source is connected to the electrodes and a voltage greater than or equal to 1.3 volts is applied to the bath. At the anode, the carbon is oxidized to form carbon dioxide and uranium chloride. At the cathode, uranium is electroplated. The uranium chloride at the cathode reacts with more uranium oxide to continue the reaction. The process may also be used with other transuranic oxides and rare earth metal oxides.

  2. Determination of arsenic, molybdenum, uranium and vanadium in seawater by neutron activation analysis after preconcentration by colloid flotation

    SciTech Connect (OSTI)

    Murthy, R.S.S.; Ryan, D.E.

    1983-04-01T23:59:59.000Z

    Colloid flotation of arsenic, molybdenum, uranium, and vanadium on hydrous iron(III) oxide permits rapid collection of the precipitate for neutron activation analysis. The precipitate is floated, in the presence of sodium dodecyl sulfate and tiny nitrogen bubbles, from 1 L of seawater at pH 5.7 +/- 0.2. Except for uranium, recoveries are better than 95%; about 75% of the uranium was recovered. Selenium(IV) and tungsten(VI) can be similarly collected but their natural concentration levels in seawater are below detection limits for 1 L volumes.

  3. Spectroscopic and Diffraction Study of Uranium Speciation in Contaminated Vadose Zone Sediments from the Hanford Site, Washington State

    SciTech Connect (OSTI)

    Catalano, Jeffrey G.; Heald, Steve M.; Zachara, John M.; Brown Jr., G E.

    2004-05-15T23:59:59.000Z

    Contamination of vadose zone sediments under tank BX-102 at the Hanford site, Washington, resulted from the accidental release of 7-8 metric tons of uranium dissolved in caustic aqueous sludge in 1951. We have applied synchrotron-based X-ray spectroscopic and diffraction techniques to characterize the speciation of uranium in samples of these contaminated sediments. U LIII-edge X-ray absorption fine structure (XAFS) spectroscopic studies demonstrate that uranium occurs predominantly as a uranium-(VI) silicate from the uranophane group of minerals. XAFS cannot distinguish between the members of this mineral group due to the near identical local coordination environments of uranium in these phases. However, these phases differ crystallographically, and can be distinguished using X-ray diffraction (XRD) methods. As the concentration of uranium was too low for conventional XRD to detect these phases, X-ray microdiffraction (?XRD) was used to collect diffraction patterns on {approx}20 ?m diameter areas of localized high uranium concentration found using microscanning X-ray fluorescence (?SXRF). Only sodium boltwoodite, Na(UO2)(SiO3OH)?1.5H2O, was observed; no other uranophane group minerals were present. Sodium boltwoodite formation has effectively sequestered uranium in these sediments under the current geochemical and hydrologic conditions. Attempts to remediate the uranium contamination will likely face significant difficulties because of the speciation and distribution of uranium in the sediments.

  4. Determination of kinetic coefficients for the simultaneous reduction of sulfate and uranium by Desulfovibrio desulfuricans bacteria

    SciTech Connect (OSTI)

    Tucker, M.D.

    1995-05-01T23:59:59.000Z

    Uranium contamination of groundwaters and surface waters near abandoned mill tailings piles is a serious concern in many areas of the western United States. Uranium usually exists in either the U(IV) or the U(VI) oxidation state. U(VI) is soluble in water and, as a result, is very mobile in the environment. U(IV), however, is generally insoluble in water and, therefore, is not subject to aqueous transport. In recent years, researchers have discovered that certain anaerobic microorganisms, such as the sulfate-reducing bacteria Desulfovibrio desulfuricans, can mediate the reduction of U(VI) to U(IV). Although the ability of this microorganism to reduce U(VI) has been studied in some detail by previous researchers, the kinetics of the reactions have not been characterized. The purpose of this research was to perform kinetic studies on Desulfovibrio desulficans bacteria during simultaneous reduction of sulfate and uranium and to determine the phase in which uranium exists after it has been reduced and precipitated from solution. The studies were conducted in a laboratory-scale chemostat under substrate-limited growth conditions with pyruvate as the substrate. Kinetic coefficients for substrate utilization and cell growth were calculated using the Monod equation. The maximum rate of substrate utilization (k) was determined to be 4.70 days{sup {minus}1} while the half-velocity constant (K{sub s}) was 140 mg/l COD. The yield coefficient (Y) was determined to be 0.17 mg cells/mg COD while the endogenous decay coefficient (k{sub d}) was calculated as 0.072 days{sup {minus}1}. After reduction, U(IV) Precipitated from solution in the uraninite (UO{sub 2}) phase. Uranium removal efficiency as high as 90% was achieved in the chemostat.

  5. EPA Update: NESHAP Uranium Activities

    E-Print Network [OSTI]

    EPA Update: NESHAP Uranium Activities Reid J. Rosnick Environmental Protection Agency Radiation Protection Division (6608J) Washington, DC 20460 NMA/NRC Uranium Recovery Workshop July 2, 2009 #12 for underground uranium mining operations (Subpart B) EPA regulatory requirements for operating uranium mill

  6. Thermodynamic stabilities of U(VI) minerals: Estimated and observed relationships

    SciTech Connect (OSTI)

    Finch, R.J. [Univ. of Manitoba, Winnipeg, Manitoba (Canada)

    1996-12-31T23:59:59.000Z

    Gibbs free energies of formation ({Delta}G{degree}{sub f}) for several structurally related U(VI) minerals are estimated by summing the Gibbs energy contributions from component oxides. The estimated {Delta}G{degree}{sub f} values are used to construct activity-activity (stability) diagrams, and the predicted stability fields are compared with observed mineral occurrences and reaction pathways. With some exceptions, natural occurrences agree well with the mineral stability fields estimated for the systems SiO{sub 2}-CaO-UO{sub 3}-H{sub 2}O and CO{sub 2}-CaO-UO{sub 3}H{sub 2}O, providing confidence in the estimated thermodynamic values. Activity-activity diagrams are sensitive to small differences in {Delta}G{degree}{sub f} values, and mineral compositions must be known accurately, including structurally bound H{sub 2}O. The estimated {Delta}G{degree}{sub f} values are not considered reliable for a few minerals for two major reasons: (1) the structures of the minerals in question are not closely similar to those used to estimate the {Delta}G{sub f}* values of the component oxides, and/or (2) the minerals in question are exceptionally fine grained, leading to large surface energies that increase the effective mineral solubilities. The thermodynamic stabilities of uranium(VI) minerals are of interest for understanding the role of these minerals in controlling uranium concentrations in oxidizing groundwaters associated with uranium ore bodies, uranium mining and mill tailings and geological repositories for nuclear waste.

  7. WISE Uranium Project - Fact Sheet

    E-Print Network [OSTI]

    Hazards From Depleted

    t in the depleted uranium. For this purpose, we first need to calculate the mass balance of the enrichment process. We then calculate the inhalation doses from the depleted uranium and compare the dose contributions from the nuclides of interest. Mass balance for uranium enrichment at Paducah [DOE_1984, p.35] Feed Product Tails Other Mass [st] 758002 124718 621894 11390 Mass fraction 100.00% 16.45% 82.04% 1.50% Concentration of plutonium in tails (depleted uranium) from enrichment of reprocessed uranium, assuming that all plutonium were transfered to the tails: Concentration of neptunium in tails from enrichment of reprocessed uranium uranium, assuming that all neptunium were transfered to the tails: - 2 - Schematic of historic uranium enrichment process at Paducah [DOE_1999b] - -7 For comparison, we first calculate the inhalation dose from depleted uranium produced from natural uranium. We assume that the short-lived decay products have reached secular equilibrium with th

  8. Assessment of Controlling Processes for Field-Scale Uranium Reactive Transport under Highly Transient Flow Conditions

    SciTech Connect (OSTI)

    Ma, Rui; Zheng, Chunmiao; Liu, Chongxuan; Greskowiak, Janek; Prommer, Henning; Zachara, John M.

    2014-02-13T23:59:59.000Z

    This paper presents the results of a comprehensive model-based analysis of a uranium tracer test conducted at the U.S Department of Energy Hanford 300 Area (300A) IFRC site. A three-dimensional multi-component reactive transport model was employed to assess the key factors and processes that control the field-scale uranium reactive transport. Taking into consideration of relevant physical and chemical processes, the selected conceptual/numerical model replicates the spatial and temporal variations of the observed U(VI) concentrations reasonably well in spite of the highly complex field conditions. A sensitivity analysis was performed to interrogate the relative importance of various processes and factors for reactive transport of U(VI) at the field-scale. The results indicate that multi-rate U(VI) sorption/desorption, U(VI) surface complexation reactions, and initial U(VI) concentrations were the most important processes and factors controlling U(VI) migration. On the other hand, cation exchange reactions, the choice of the surface complexation model, and dual-domain mass transfer processes, which were previously identified to be important in laboratory experiments, played less important roles under the field-scale experimental condition at the 300A site. However, the model simulations also revealed that the groundwater chemistry was relatively stable during the uranium tracer experiment and therefore presumably not dynamic enough to appropriately assess the effects of ion exchange reaction and the choice of surface complexation models on U(VI) sorption and desorption. Furthermore, it also showed that the field experimental duration (16 days) was not sufficiently long to precisely assess the role of a majority of the sorption sites that were accessed by slow kinetic processes within the dual domain model. The sensitivity analysis revealed the crucial role of the intraborehole flow that occurred within the long-screened monitoring wells and thus significantly affected both field-scale measurements and simulated U(VI) concentrations as a combined effect of aquifer heterogeneity and highly dynamic flow conditions. Overall, this study, which provides one of the few detailed and highly data-constrained uranium transport simulations, highlights the difference in controlling processes between laboratory and field scale that prevent a simple direct upscaling of laboratory-scale models.

  9. India's Worsening Uranium Shortage

    SciTech Connect (OSTI)

    Curtis, Michael M.

    2007-01-15T23:59:59.000Z

    As a result of NSG restrictions, India cannot import the natural uranium required to fuel its Pressurized Heavy Water Reactors (PHWRs); consequently, it is forced to rely on the expediency of domestic uranium production. However, domestic production from mines and byproduct sources has not kept pace with demand from commercial reactors. This shortage has been officially confirmed by the Indian Planning Commission’s Mid-Term Appraisal of the country’s current Five Year Plan. The report stresses that as a result of the uranium shortage, Indian PHWR load factors have been continually decreasing. The Uranium Corporation of India Ltd (UCIL) operates a number of underground mines in the Singhbhum Shear Zone of Jharkhand, and it is all processed at a single mill in Jaduguda. UCIL is attempting to aggrandize operations by establishing new mines and mills in other states, but the requisite permit-gathering and development time will defer production until at least 2009. A significant portion of India’s uranium comes from byproduct sources, but a number of these are derived from accumulated stores that are nearing exhaustion. A current maximum estimate of indigenous uranium production is 430t/yr (230t from mines and 200t from byproduct sources); whereas, the current uranium requirement for Indian PHWRs is 455t/yr (depending on plant capacity factor). This deficit is exacerbated by the additional requirements of the Indian weapons program. Present power generation capacity of Indian nuclear plants is 4350 MWe. The power generation target set by the Indian Department of Atomic Energy (DAE) is 20,000 MWe by the year 2020. It is expected that around half of this total will be provided by PHWRs using indigenously supplied uranium with the bulk of the remainder provided by breeder reactors or pressurized water reactors using imported low-enriched uranium.

  10. Depleted uranium management alternatives

    SciTech Connect (OSTI)

    Hertzler, T.J.; Nishimoto, D.D.

    1994-08-01T23:59:59.000Z

    This report evaluates two management alternatives for Department of Energy depleted uranium: continued storage as uranium hexafluoride, and conversion to uranium metal and fabrication to shielding for spent nuclear fuel containers. The results will be used to compare the costs with other alternatives, such as disposal. Cost estimates for the continued storage alternative are based on a life-cycle of 27 years through the year 2020. Cost estimates for the recycle alternative are based on existing conversion process costs and Capital costs for fabricating the containers. Additionally, the recycle alternative accounts for costs associated with intermediate product resale and secondary waste disposal for materials generated during the conversion process.

  11. Role of U(VI) Adsorption in U(VI) Reduction by Geobacter Species.

    SciTech Connect (OSTI)

    None, None

    2009-03-09T23:59:59.000Z

    Previous work had suggested that Acholeplasma palmae has a higher capacity for uranium sorption than other bacteria studied. Sorption studies were performed with cells in suspension in various solutions containing uranium and results were used to generate uranium-biosorption isotherms.

  12. Biogeochemical Processes In Ethanol Stimulated Uranium Contaminated Subsurface Sediments

    SciTech Connect (OSTI)

    Mohanty, Santosh R.; Kollah, Bharati; Hedrick, David B.; Peacock, Aaron D.; Kukkadapu, Ravi K.; Roden, Eric E.

    2008-06-15T23:59:59.000Z

    A laboratory incubation experiment was conducted with uranium contaminated subsurface sediment to assess the geochemical and microbial community response to ethanol amendment. A classical sequence of TEAPs was observed in ethanol-amended slurries, with NO3- reduction, Fe(III) reduction, SO4 2- reduction, and CH4 production proceeding in sequence until all of the added 13C-ethanol (9 mM) was consumed. Approximately 60% of the U(VI) content of the sediment was reduced during the period of Fe(III) reduction. No additional U(VI) reduction took place during the sulfate-reducing and methanogenic phases of the experiment. Only gradual reduction of NO3 -, and no reduction of U(VI), took place in ethanol-free slurries. Stimulation of additional Fe(III) or SO4 2- reduction in the ethanol-amended slurries failed to promote further U(VI) reduction. Reverse transcribed 16S rRNA clone libraries revealed major increases in the abundance of organisms related to Dechloromonas, Geobacter, and Oxalobacter in the ethanolamended slurries. PLFAs indicative of Geobacter showed a distinct increase in the amended slurries, and analysis of PLFA 13C/12C ratios confirmed the incorporation of ethanol into these PLFAs. A increase in the abundance of 13C-labeled PLFAs indicative of Desulfobacter, Desulfotomaculum, and Desulfovibrio took place during the brief period of sulfate reduction which followed the Fe(III) reduction phase. Our results show that major redox processes in ethanol-amended sediments can be reliably interpreted in terms of standard conceptual models of TEAPs in sediments. However, the redox speciation of uranium is complex and cannot be explained based on simplified thermodynamic considerations.

  13. VI Congreso de CEISAL: Independencias Dependencias Interdependencias

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 VI Congreso de CEISAL: Independencias ­ Dependencias ­ Interdependencias Toulouse, 30 de Junio al avances del bloque hacia la integración. Esa tendencia no se contradice con la existencia de determinados

  14. Microbiological, Geochemical and Hydrologic Processes Controlling Uranium Mobility: An Integrated Field-Scale Subsurface Research Challenge Site at Rifle, Colorado, Quality Assurance Project Plan

    SciTech Connect (OSTI)

    Fix, N. J.

    2008-01-07T23:59:59.000Z

    The U.S. Department of Energy (DOE) is cleaning up and/or monitoring large, dilute plumes contaminated by metals, such as uranium and chromium, whose mobility and solubility change with redox status. Field-scale experiments with acetate as the electron donor have stimulated metal-reducing bacteria to effectively remove uranium [U(VI)] from groundwater at the Uranium Mill Tailings Site in Rifle, Colorado. The Pacific Northwest National Laboratory and a multidisciplinary team of national laboratory and academic collaborators has embarked on a research proposed for the Rifle site, the object of which is to gain a comprehensive and mechanistic understanding of the microbial factors and associated geochemistry controlling uranium mobility so that DOE can confidently remediate uranium plumes as well as support stewardship of uranium-contaminated sites. This Quality Assurance Project Plan provides the quality assurance requirements and processes that will be followed by the Rifle Integrated Field-Scale Subsurface Research Challenge Project.

  15. 300 AREA URANIUM CONTAMINATION

    SciTech Connect (OSTI)

    BORGHESE JV

    2009-07-02T23:59:59.000Z

    {sm_bullet} Uranium fuel production {sm_bullet} Test reactor and separations experiments {sm_bullet} Animal and radiobiology experiments conducted at the. 331 Laboratory Complex {sm_bullet} .Deactivation, decontamination, decommissioning,. and demolition of 300 Area facilities

  16. Method for the recovery of uranium values from uranium tetrafluoride

    DOE Patents [OSTI]

    Kreuzmann, Alvin B. (Cincinnati, OH)

    1983-01-01T23:59:59.000Z

    The invention is a novel method for the recovery of uranium from dry, particulate uranium tetrafluoride. In one aspect, the invention comprises reacting particulate uranium tetrafluoride and calcium oxide in the presence of gaseous oxygen to effect formation of the corresponding alkaline earth metal uranate and alkaline earth metal fluoride. The product uranate is highly soluble in various acidic solutions wherein the product fluoride is virtually insoluble therein. The product mixture of uranate and alkaline earth metal fluoride is contacted with a suitable acid to provide a uranium-containing solution, from which the uranium is recovered. The invention can achieve quantitative recovery of uranium in highly pure form.

  17. Method for the recovery of uranium values from uranium tetrafluoride

    DOE Patents [OSTI]

    Kreuzmann, A.B.

    1982-10-27T23:59:59.000Z

    The invention is a novel method for the recovery of uranium from dry, particulate uranium tetrafluoride. In one aspect, the invention comprises reacting particulate uranium tetrafluoride and calcium oxide in the presence of gaseous oxygen to effect formation of the corresponding alkaline earth metal uranate and alkaline earth metal fluoride. The product uranate is highly soluble in various acidic solutions whereas the product fluoride is virtually insoluble therein. The product mixture of uranate and alkaline earth metal fluoride is contacted with a suitable acid to provide a uranium-containing solution, from which the uranium is recovered. The invention can achieve quantitative recovery of uranium in highly pure form.

  18. Study of Chemical Changes in Uranium Oxyfluoride Particles Progress Report June 2008 - February 2009

    SciTech Connect (OSTI)

    Kips, R S; Kristo, M J; Hutcheon, I D

    2009-02-25T23:59:59.000Z

    The present study aims to demonstrate how knowledge of time-dependent changes in uranium oxyfluoride particles can benefit particle analyses for environmental sampling. Environmental sampling depends upon laboratory analysis of nuclear material that has often been exposed to the environment after it was produced. It is therefore important to understand how those environmental conditions might have changed the chemical composition of the material over time. To investigate this, we prepared a set of uranium oxyfluoride particles at the Institute for Reference Materials and Measurements (IRMM-DG Joint Research Centre of the European Commission, Belgium). These UO{sub 2}F{sub 2} particles were prepared from the release and subsequent hydrolysis of UF{sub 6} gas, and were stored at LLNL in environmental chambers, set to different humidity, temperature and lighting conditions. An experimental plan was drafted to assess the number of analyses required to track the changes in particle composition, morphology, and structure. Due to its high spatial resolution and excellent transmission, the NanoSIMS secondary ion mass spectrometer at LLNL was found to be the optimal tool to measure individual oxyfluoride particles. This was confirmed by our participation in the inter-laboratory measurement campaign for particle analysis (NUSIMEP-6), organized by the IRMM in June last year. The reported uranium isotope ratios demonstrated the precision and accuracy of the NanoSIMS and ims 3f SIMS measurements at LLNL, and provided a high degree of confidence that the new measurements on the UO{sub 2}F{sub 2} samples will be of comparable high quality. As fluorine is known to be a chemically-sensitive compound, we measured the intensity of the fluorine secondary ions relative to the ions generated by the matrix to evaluate the rate of particle degradation under different environmental conditions. A relative sensitivity factor was empirically determined to convert these measurements to absolute fluorine concentrations. Additional measurements in selected uranium compounds were carried out to account for variations in matrix composition. Because of the complexity of both the SIMS instruments, as well as the nature of the samples, we spent a substantial amount of time on instrument training and instrument set up. The latest NanoSIMS measurements on the freshly-prepared UO{sub 2}F{sub 2} particles however, showed that we are on the right track when it comes to determining the chemical changes in individual uranium particles. At PNNL, several optical techniques including cryogenic laser-induced time-resolved U(VI) fluorescence micro-spectroscopy, Raman spectroscopy, and Fourier transform infrared spectroscopy will be applied to investigate molecular transformations of the particles. As a control, dynamic SIMS measurements will also be performed on a subset of the samples sent to PNNL.

  19. Biogeochemical Processes In Ethanol Stimulated Uranium Contaminated...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Processes In Ethanol Stimulated Uranium Contaminated Subsurface Sediments. Biogeochemical Processes In Ethanol Stimulated Uranium Contaminated Subsurface Sediments. Abstract: A...

  20. Evidence for Multiple Modes of Uranium Immobilization by an Anaerobic Bacterium

    SciTech Connect (OSTI)

    Ray, Allison; Bargar, John R.; Sivaswamy, Vaideeswaran; Dohnalkova, Alice; Fujita, Yoshiko; Peyton, Brent M.; Magnuson, Timothy S.

    2011-05-15T23:59:59.000Z

    Microbial reduction of hexavalent uranium has been studied widely for its potential role in bioremediation and immobilization of soluble U(VI) in contaminated groundwater. More recently, some microorganisms have been examined for their role in immobilization of U(VI) via precipitation of uranyl phosphate minerals mediated by microbial phosphate release, alleviating the requirement for long-term redox control. Here, we investigated the mechanism of U(VI) removal mediated by an environmental isolate, strain UFO1, that is indigenous to the Field Research Center (FRC) in Oak Ridge, TN and has been detected in U(VI)-contaminated sediments. Changes in U(VI) speciation were examined in the presence and absence of the electron-shuttling moiety, anthraquinone-2,6-disulfonate (AQDS). Cell suspensions were capable of nearly complete removal of 100 ?M U(VI) from solution within 48 hours; U(VI) removal was not dependent on the presence of an exogenous electron donor or AQDS, although AQDS increased the rate of U(VI) removal. X-ray Absorption Near Edge Structure (XANES) spectroscopic measurements indicated that U(IV) was the predominant oxidation state of uranium in cell suspensions in both the absence and presence of 100 ?M AQDS. However, extended X-ray Absorption Fine Structure spectroscopy (EXAFS) measurements indicated that 17% of the cell-associated precipitates in a U(VI)-treated suspension that lacked AQDS had spectral characteristics consistent with a uranyl phosphate solid phase. The potential involvement of phosphate was consistent with observed increases in soluble phosphate concentrations over time in UFO1 cell suspensions, which suggested phosphate liberation from the cells. TEM-EDS confirmed the presence of uranyl phosphate with a U:P ratio consistent with autunite (1:1). EXAFS analyses further showed that U(IV) was present predominantly as a monomeric complex sorbed to carboxylate functional groups on biomass and also suggested that a fraction of the U(IV) was coordinated to phosphoryl ligands. These results suggest that strain UFO1 has the ability to facilitate U(VI) removal from solution via both reductive and phosphate precipitation mechanisms, and may potentially be useful for the remediation of U-contaminated sediments at the FRC or elsewhere.

  1. Evidence for Multiple Modes of Uranium Immobilization by an Anaerobic Bacterium

    SciTech Connect (OSTI)

    Allison E. Ray; John R. Bargar; Alice C. Dohnalkova; Vaidee Sivaswamy; Yoshiko Fujita; Timothy S. Magnuson

    2011-05-01T23:59:59.000Z

    ABSTRACT Microbial reduction of hexavalent uranium has been studied widely for its potential role in bioremediation and removal of soluble U(VI) from contaminated groundwater. More recently, some microorganisms have been examined for their role in immobilization of U(VI) via precipitation of uranyl phosphate minerals mediated by microbial phosphate release, alleviating the requirement for long-term redox control. Here, we investigated the mechanism of U(VI) removal mediated by an environmental isolate, strain UFO1, that is indigenous to the Field Research Center (FRC) in Oak Ridge, TN and has been detected in U(VI)-contaminated sediments. U(VI) removal was examined in the presence and absence of the electron-shuttling moiety, anthraquinone-2,6-disulfonate (AQDS). Cell suspensions were capable of the near complete removal of 100 uM U(VI) from solution within 48 hours; U(VI) removal was not dependent on the presence of an exogenous electron donor or AQDS, although AQDS increased the rate of U(VI) removal. Profiles of ortho-phosphate concentration over time suggested phosphate liberation from cells. However, X-ray Absorption Near Edge Structure (XANES) spectroscopic measurements indicated that U(IV) was the predominant oxidation state of uranium in cell suspensions in both the absence and presence of 100 uM AQDS. Extended X-ray Absorption Fine Structure spectroscopy (EXAFS) measurements indicated that 20% of the cell-associated precipitates in a U(VI)-treated suspension that lacked AQDS had spectral characteristics consistent with a uranyl phosphate solid phase. EXAFS fits further show that that U(IV) is present dominantly as a monomeric sorbed complex. TEM-EDS confirmed the presence of uranyl phosphate with a U:P ratio consistent with autunite (1:1). These results suggest that strain UFO1 has the ability to mediate U(VI) removal from solution via both reductive and phosphate precipitation mechanisms, and may potentially be useful for the remediation of U-contaminated sediments at the FRC.

  2. Acceleration of Field-Scale Bioreduction of U(VI) in a Shallow Alluvial Aquifer: Temporal and Spatial Evolution of Biogeochemistry

    SciTech Connect (OSTI)

    Long, Phil

    2005-04-20T23:59:59.000Z

    Uranium mill tailings sites provide access to uranium-contaminated groundwater at sites that are shallow and low hazard, making it possible to address the following scientific objectives: (1) Determine the dominant electron accepting processes at field sites with long-term metal/rad contamination; (2) Define the biogeochemical transformations that may be important to either natural or accelerated bioremediation under field conditions; and (3) Examine the potential for using biostimulation (electron donor addition) to accelerate reduction of U(VI) to U(IV) at the field scale.

  3. Process for electrolytically preparing uranium metal

    DOE Patents [OSTI]

    Haas, Paul A. (Knoxville, TN)

    1989-01-01T23:59:59.000Z

    A process for making uranium metal from uranium oxide by first fluorinating uranium oxide to form uranium tetrafluoride and next electrolytically reducing the uranium tetrafluoride with a carbon anode to form uranium metal and CF.sub.4. The CF.sub.4 is reused in the fluorination reaction rather than being disposed of as a hazardous waste.

  4. Controlling uranium reactivity March 18, 2008

    E-Print Network [OSTI]

    Meyer, Karsten

    for the last decade. Most of their work involves depleted uranium, a more common form of uraniumMarch 2008 Controlling uranium reactivity March 18, 2008 Uranium is an often misunderstood metal uranium research. In reality, uranium presents a wealth of possibilities for funda- mental chemistry. Many

  5. Influence of uranium hydride oxidation on uranium metal behaviour

    SciTech Connect (OSTI)

    Patel, N.; Hambley, D. [National Nuclear Laboratory (United Kingdom); Clarke, S.A. [Sellafield Ltd (United Kingdom); Simpson, K.

    2013-07-01T23:59:59.000Z

    This work addresses concerns that the rapid, exothermic oxidation of active uranium hydride in air could stimulate an exothermic reaction (burning) involving any adjacent uranium metal, so as to increase the potential hazard arising from a hydride reaction. The effect of the thermal reaction of active uranium hydride, especially in contact with uranium metal, does not increase in proportion with hydride mass, particularly when considering large quantities of hydride. Whether uranium metal continues to burn in the long term is a function of the uranium metal and its surroundings. The source of the initial heat input to the uranium, if sufficient to cause ignition, is not important. Sustained burning of uranium requires the rate of heat generation to be sufficient to offset the total rate of heat loss so as to maintain an elevated temperature. For dense uranium, this is very difficult to achieve in naturally occurring circumstances. Areas of the uranium surface can lose heat but not generate heat. Heat can be lost by conduction, through contact with other materials, and by convection and radiation, e.g. from areas where the uranium surface is covered with a layer of oxidised material, such as burned-out hydride or from fuel cladding. These rates of heat loss are highly significant in relation to the rate of heat generation by sustained oxidation of uranium in air. Finite volume modelling has been used to examine the behaviour of a magnesium-clad uranium metal fuel element within a bottle surrounded by other un-bottled fuel elements. In the event that the bottle is breached, suddenly, in air, it can be concluded that the bulk uranium metal oxidation reaction will not reach a self-sustaining level and the mass of uranium oxidised will likely to be small in relation to mass of uranium hydride oxidised. (authors)

  6. Model-Based Analysis of the Role of Biological, Hydrological and Geochemical Factors Affecting Uranium Bioremediation

    SciTech Connect (OSTI)

    Zhao, Jiao; Scheibe, Timothy D.; Mahadevan, Radhakrishnan

    2011-01-24T23:59:59.000Z

    Uranium contamination is a serious concern at several sites motivating the development of novel treatment strategies such as the Geobacter-mediated reductive immobilization of uranium. However, this bioremediation strategy has not yet been optimized for the sustained uranium removal. While several reactive-transport models have been developed to represent Geobacter-mediated bioremediation of uranium, these models often lack the detailed quantitative description of the microbial process (e.g., biomass build-up in both groundwater and sediments, electron transport system, etc.) and the interaction between biogeochemical and hydrological process. In this study, a novel multi-scale model was developed by integrating our recent model on electron capacitance of Geobacter (Zhao et al., 2010) with a comprehensive simulator of coupled fluid flow, hydrologic transport, heat transfer, and biogeochemical reactions. This mechanistic reactive-transport model accurately reproduces the experimental data for the bioremediation of uranium with acetate amendment. We subsequently performed global sensitivity analysis with the reactive-transport model in order to identify the main sources of prediction uncertainty caused by synergistic effects of biological, geochemical, and hydrological processes. The proposed approach successfully captured significant contributing factors across time and space, thereby improving the structure and parameterization of the comprehensive reactive-transport model. The global sensitivity analysis also provides a potentially useful tool to evaluate uranium bioremediation strategy. The simulations suggest that under difficult environments (e.g., highly contaminated with U(VI) at a high migration rate of solutes), the efficiency of uranium removal can be improved by adding Geobacter species to the contaminated site (bioaugmentation) in conjunction with the addition of electron donor (biostimulation). The simulations also highlight the interactive effect of initial cell concentration and flow rate on U(VI) reduction.

  7. Uranium resources: Issues and facts

    SciTech Connect (OSTI)

    Delene, J.G.

    1993-12-31T23:59:59.000Z

    Although there are several secondary issues, the most important uranium resource issue is, ``will there be enough uranium available at a cost which will allow nuclear power to be competitive in the future?`` This paper will attempt to answer this question by discussing uranium supply, demand, and economics from the perspective of the United States. The paper will discuss: how much uranium is available; the sensitivity of nuclear power costs to uranium price; the potential future demand for uranium in the Unites States, some of the options available to reduce this demand, the potential role of the Advanced Liquid Metal Cooled Reactor (ALMR) in reducing uranium demand; and potential alternative uranium sources and technologies.

  8. Uranium-titanium-niobium alloy

    DOE Patents [OSTI]

    Ludtka, Gail M. (Oak Ridge, TN); Ludtka, Gerard M. (Oak Ridge, TN)

    1990-01-01T23:59:59.000Z

    A uranium alloy having small additions of Ti and Nb shows improved strength and ductility in cross section of greater than one inch over prior uranium alloy having only Ti as an alloying element.

  9. Uranium hexafluoride handling. Proceedings

    SciTech Connect (OSTI)

    Not Available

    1991-12-31T23:59:59.000Z

    The United States Department of Energy, Oak Ridge Field Office, and Martin Marietta Energy Systems, Inc., are co-sponsoring this Second International Conference on Uranium Hexafluoride Handling. The conference is offered as a forum for the exchange of information and concepts regarding the technical and regulatory issues and the safety aspects which relate to the handling of uranium hexafluoride. Through the papers presented here, we attempt not only to share technological advances and lessons learned, but also to demonstrate that we are concerned about the health and safety of our workers and the public, and are good stewards of the environment in which we all work and live. These proceedings are a compilation of the work of many experts in that phase of world-wide industry which comprises the nuclear fuel cycle. Their experience spans the entire range over which uranium hexafluoride is involved in the fuel cycle, from the production of UF{sub 6} from the naturally-occurring oxide to its re-conversion to oxide for reactor fuels. The papers furnish insights into the chemical, physical, and nuclear properties of uranium hexafluoride as they influence its transport, storage, and the design and operation of plant-scale facilities for production, processing, and conversion to oxide. The papers demonstrate, in an industry often cited for its excellent safety record, continuing efforts to further improve safety in all areas of handling uranium hexafluoride. Selected papers were processed separately for inclusion in the Energy Science and Technology Database.

  10. Uranium deposits of Brazil

    SciTech Connect (OSTI)

    NONE

    1991-09-01T23:59:59.000Z

    Brazil is a country of vast natural resources, including numerous uranium deposits. In support of the country`s nuclear power program, Brazil has developed the most active uranium industry in South America. Brazil has one operating reactor (Angra 1, a 626-MWe PWR), and two under construction. The country`s economic challenges have slowed the progress of its nuclear program. At present, the Pocos de Caldas district is the only active uranium production. In 1990, the Cercado open-pit mine produced approximately 45 metric tons (MT) U{sub 3}O{sub 8} (100 thousand pounds). Brazil`s state-owned uranium production and processing company, Uranio do Brasil, announced it has decided to begin shifting its production from the high-cost and nearly depleted deposits at Pocos de Caldas, to lower-cost reserves at Lagoa Real. Production at Lagoa Real is schedules to begin by 1993. In addition to these two districts, Brazil has many other known uranium deposits, and as a whole, it is estimated that Brazil has over 275,000 MT U{sub 3}O{sub 8} (600 million pounds U{sub 3}O{sub 8}) in reserves.

  11. Uranium for hydrogen storage applications : a materials science perspective.

    SciTech Connect (OSTI)

    Shugard, Andrew D.; Tewell, Craig R.; Cowgill, Donald F.; Kolasinski, Robert D.

    2010-08-01T23:59:59.000Z

    Under appropriate conditions, uranium will form a hydride phase when exposed to molecular hydrogen. This makes it quite valuable for a variety of applications within the nuclear industry, particularly as a storage medium for tritium. However, some aspects of the U+H system have been characterized much less extensively than other common metal hydrides (particularly Pd+H), likely due to radiological concerns associated with handling. To assess the present understanding, we review the existing literature database for the uranium hydride system in this report and identify gaps in the existing knowledge. Four major areas are emphasized: {sup 3}He release from uranium tritides, the effects of surface contamination on H uptake, the kinetics of the hydride phase formation, and the thermal desorption properties. Our review of these areas is then used to outline potential avenues of future research.

  12. Selective Recovery of Enriched Uranium from Inorganic Wastes

    SciTech Connect (OSTI)

    Kimura, R. T.

    2003-02-26T23:59:59.000Z

    Uranium as U(IV) and U(VI) can be selectively recovered from liquids and sludge containing metal precipitates, inorganic salts, sand and silt fines, debris, other contaminants, and slimes, which are very difficult to de-water. Chemical processes such as fuel manufacturing and uranium mining generate enriched and natural uranium-bearing wastes. This patented Framatome ANP (FANP) uranium recovery process reduces uranium losses, significantly offsets waste disposal costs, produces a solid waste that meets mixed-waste disposal requirements, and does not generate metal-contaminated liquids. At the head end of the process is a floating dredge that retrieves liquids, sludge, and slimes in the form of a slurry directly from the floor of a lined surface impoundment (lagoon). The slurry is transferred to and mixed in a feed tank with a turbine mixer and re-circulated to further break down the particles and enhance dissolution of uranium. This process uses direct steam injection and sodium hypochlorite addition to oxidize and dissolves any U(IV). Cellulose is added as a non-reactive filter aid to help filter slimes by giving body to the slurry. The slurry is pumped into a large recessed-chamber filter press then de-watered by a pressure cycle-controlled double-diaphragm pump. U(VI) captured in the filtrate from this process is then precipitated by conversion to U(IV) in another Framatome ANP-patented process which uses a strong reducing agent to crystallize and settle the U(IV) product. The product is then dewatered in a small filter press. To-date, over 3,000 Kgs of U at 3% U-235 enrichment were recovered from a 8100 m2 hypalon-lined surface impoundment which contained about 10,220 m3 of liquids and about 757 m3 of sludge. A total of 2,175 drums (0.208 m3 or 55 gallon each) of solid mixed-wastes have been packaged, shipped, and disposed. In addition, 9463 m3 of low-U liquids at <0.001 KgU/m3 were also further processed and disposed.

  13. Corrosion-resistant uranium

    DOE Patents [OSTI]

    Hovis, V.M. Jr.; Pullen, W.C.; Kollie, T.G.; Bell, R.T.

    1981-10-21T23:59:59.000Z

    The present invention is directed to the protecting of uranium and uranium alloy articles from corrosion by providing the surfaces of the articles with a layer of an ion-plated metal selected from aluminum and zinc to a thickness of at least 60 microinches and then converting at least the outer surface of the ion-plated layer of aluminum or zinc to aluminum chromate or zinc chromate. This conversion of the aluminum or zinc to the chromate form considerably enhances the corrosion resistance of the ion plating so as to effectively protect the coated article from corrosion.

  14. Subsurface Biogeochemical Heterogeneity (Field-scale removal of U(VI) from groundwater in an alluvial aquifer by electron donor amendment)

    SciTech Connect (OSTI)

    Long, Philip E.; Derek R. Lovley; A. L. N’Guessan; Kelly Nevin; C. T. Resch; Evan Arntzen; Jenny Druhan; Aaron Peacock; Brett Baldwin; Dick Dayvault; Dawn Holmes; Ken Williams; Susan Hubbard; Steve Yabusaki; Yilin Fang; D.C. White; John Komlos; Peter Jaffe

    2006-06-01T23:59:59.000Z

    Determine if biostimulation of alluvial aquifers by electron donor amendment can effectively remove U(VI) from groundwater at the field scale. Uranium contamination in groundwater is a significant problem at several DOE sites. In this project, the possibility of accelerating bioreduction of U(VI) to U(IV) as a means of decreasing U(VI) concentrations in groundwater is directly addressed by conducting a series of field-scale experiments. Scientific goals include demonstrating the quantitative linkage between microbial activity and U loss from groundwater and relating the dominant terminal electron accepting processes to the rate of U loss. The project is currently focused on understanding the mechanisms for unexpected long-term ({approx}2 years) removal of U after stopping electron donor amendment. Results obtained in the project successfully position DOE and others to apply biostimulation broadly to U contamination in alluvial aquifers.

  15. High loading uranium fuel plate

    DOE Patents [OSTI]

    Wiencek, Thomas C. (Bolingbrook, IL); Domagala, Robert F. (Indian Head Park, IL); Thresh, Henry R. (Palos Heights, IL)

    1990-01-01T23:59:59.000Z

    Two embodiments of a high uranium fuel plate are disclosed which contain a meat comprising structured uranium compound confined between a pair of diffusion bonded ductile metal cladding plates uniformly covering the meat, the meat having a uniform high fuel loading comprising a content of uranium compound greater than about 45 Vol. % at a porosity not greater than about 10 Vol. %. In a first embodiment, the meat is a plurality of parallel wires of uranium compound. In a second embodiment, the meat is a dispersion compact containing uranium compound. The fuel plates are fabricated by a hot isostatic pressing process.

  16. X-RAYING THE INTERGALACTIC O VI ABSORBERS

    E-Print Network [OSTI]

    Yao, Y.

    The observed intergalactic O vi absorbers at z > 0 have been regarded as a significant reservoir of the “missing

  17. April 22, 2010 Seismic Reflection VI

    E-Print Network [OSTI]

    Ito, Garrett

    4/21/2010 1 GG450 April 22, 2010 Seismic Reflection VI Data Interpretation II Today's material section Chrono- stratigraphic section Relations of strata to boundaries of a depositional sequence Seismic stratigraphic reflection terminations within an idealized seismic sequence Reflection configurations #12

  18. FINAL DRAFT VI. Application 3: Recruitment Prediction

    E-Print Network [OSTI]

    Miller, Tom

    FINAL DRAFT 106 VI. Application 3: Recruitment Prediction Contributors: S. Sarah Hinckley, Bernard Megrey, Thomas Miller Definition What do we mean by recruitment prediction? The first thing to consider in defining this term is the time horizon of the prediction. Short-term predictions mean the use of individual

  19. Thorium and uranium diphosphonates: Syntheses, structures, and spectroscopic properties

    SciTech Connect (OSTI)

    Adelani, Pius O. [Department of Civil Engineering and Geological Sciences, and Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 (United States); Albrecht-Schmitt, Thomas E., E-mail: talbrec1@nd.edu [156 Fitzpatrick Hall, University of Notre Dame, Notre Dame, IN 46556 (United States)

    2012-08-15T23:59:59.000Z

    Four new thorium and uranium diphosphonate compounds, [H{sub 3}O]{l_brace}Th{sub 2}[C{sub 6}H{sub 4}(PO{sub 3}){sub 2}]{sub 2}F{r_brace} (Thbbp-1), An{sub 2}{l_brace}(O{sub 3}PC{sub 6}H{sub 4}PO{sub 3}H){sub 2}[C{sub 6}H{sub 4}(PO{sub 3}H){sub 2}]{r_brace} [An=Th(IV), U(IV)] (Thbbp-2)/(U4bbp), and [(C{sub 2}H{sub 5})(CH{sub 3}){sub 3}N][(UO{sub 2}){sub 3}(O{sub 3}PC{sub 6}H{sub 4}PO{sub 3}H){sub 2}F(H{sub 2}O)] (U6bbp) have been synthesized hydrothermally using 1,4-benzenebisphosphonic acid as ligand. The crystal structures of these compounds were determined by single crystal X-ray diffraction. Thbbp-1 and Thbbp-2 contain seven-coordinate Th(IV) within ThO{sub 6}F and ThO{sub 7} units with capped trigonal prismatic and capped octahedral geometries, respectively. U4bbp is isotypic with Thbbp-2. The structure of U6bbp contains U(VI) is the common seven-coordinate pentagonal bipyramid. - Graphical abstract: Coordination polyhedra and luminescence properties in thorium and uranium compounds. Highlights: Black-Right-Pointing-Pointer Three-dimensional thorium and uranium complexes. Black-Right-Pointing-Pointer Conversion of U(VI) to U(IV) under hydrothermal condition. Black-Right-Pointing-Pointer Unusual seven-coordinate thorium complexes exhibiting capped octahedral and capped trigonal prismatic geometries.

  20. Uranium from seawater

    SciTech Connect (OSTI)

    Gregg, D.; Folkendt, M.

    1982-09-21T23:59:59.000Z

    A novel process for recovering uranium from seawater is proposed and some of the critical technical parameters are evaluated. The process, in summary, consists of two different options for contacting adsorbant pellets with seawater without pumping the seawater. It is expected that this will reduce the mass handling requirements, compared to pumped seawater systems, by a factor of approximately 10/sup 5/, which should also result in a large reduction in initial capital investment. Activated carbon, possibly in combination with a small amount of dissolved titanium hydroxide, is expected to be the preferred adsorbant material instead of the commonly assumed titanium hydroxide alone. The activated carbon, after exposure to seawater, can be stripped of uranium with an appropriate eluant (probably an acid) or can be burned for its heating value (possible in a power plant) leaving the uranium further enriched in its ash. The uranium, representing about 1% of the ash, is then a rich ore and would be recovered in a conventional manner. Experimental results have indicated that activated carbon, acting alone, is not adequately effective in adsorbing the uranium from seawater. We measured partition coefficients (concentration ratios) of approximately 10/sup 3/ in seawater instead of the reported values of 10/sup 5/. However, preliminary tests carried out in fresh water show considerable promise for an extraction system that uses a combination of dissolved titanium hydroxide (in minute amounts) which forms an insoluble compound with the uranyl ion, and the insoluble compound then being sorbed out on activated carbon. Such a system showed partition coefficients in excess of 10/sup 5/ in fresh water. However, the system was not tested in seawater.

  1. Uranium in Hanford Site 300 Area: Extraction Data on Borehole Sediments

    SciTech Connect (OSTI)

    Wang, Guohui; Serne, R. Jeffrey; Lindberg, Michael J.; Um, Wooyong; Bjornstad, Bruce N.; Williams, Benjamin D.; Kutynakov, I. V.; Wang, Zheming; Qafoku, Nikolla

    2012-11-26T23:59:59.000Z

    In this study, sediments collected from boreholes drilled in 2010 and 2011 as part of a remedial investigation/feasibility study were characterized. The wells, located within or around two process ponds and one process trench waste site, were characterized in terms of total uranium concentration, mobile fraction of uranium, particle size, and moisture content along the borehole depth. In general, the gravel-dominated sediments of the vadose zone Hanford formation in all investigated boreholes had low moisture contents. Based on total uranium content, a total of 48 vadose zone and periodically rewetted zone sediment samples were selected for more detailed characterization, including measuring the concentration of uranium extracted with 8 M nitric acid, and leached using bicarbonate mixed solutions to determine the liable uranium (U(VI)) contents. In addition, water extraction was conducted on 17 selected sediments. Results from the sediment acid and bicarbonate extractions indicated the total concentrations of anthropogenic labile uranium in the sediments varied among the investigated boreholes. The peak uranium concentration (114.84 µg/g, acid extract) in <2-mm size fractions was found in borehole 399 1-55, which was drilled directly in the southwest corner of the North Process Pond. Lower uranium concentrations (~0.3–2.5 µg/g, acid extract) in <2-mm size fractions were found in boreholes 399-1-57, 399-1-58, and 399-1-59, which were drilled either near the Columbia River or inland and upgradient of any waste process ponds or trenches. A general trend of “total” uranium concentrations was observed that increased as the particle size decreased when relating the sediment particle size and acid extractable uranium concentrations in two selected sediment samples. The labile uranium bicarbonate leaching kinetic experiments on three selected sediments indicated a two-step leaching rate: an initial rapid release, followed by a slow continual release of uranium from the sediment. Based on the uranium leaching kinetic results, quasi equilibrium can be assumed after 1000-h batch reaction time in this study.

  2. Evaluation of health effects in Sequoyah Fuels Corporation workers from accidental exposure to uranium hexafluoride

    SciTech Connect (OSTI)

    Fisher, D.R. (Pacific Northwest Lab., Richland, WA (USA)); Swint, M.J.; Kathren, R.L. (Hanford Environmental Health Foundation, Richland, WA (USA))

    1990-05-01T23:59:59.000Z

    Urine bioassay measurements for uranium and medical laboratory results were studied to determine whether there were any health effects from uranium intake among a group of 31 workers exposed to uranium hexafluoride (UF{sub 6}) and hydrolysis products following the accidental rupture of a 14-ton shipping cylinder in early 1986 at the Sequoyah Fuels Corporation uranium conversion facility in Gore, Oklahoma. Physiological indicators studied to detect kidney tissue damage included tests for urinary protein, casts and cells, blood, specific gravity, and urine pH, blood urea nitrogen, and blood creatinine. We concluded after reviewing two years of follow-up medical data that none of the 31 workers sustained any observable health effects from exposure to uranium. The early excretion of uranium in urine showed more rapid systemic uptake of uranium from the lung than is assumed using the International Commission on Radiological Protection (ICRP) Publication 30 and Publication 54 models. The urinary excretion data from these workers were used to develop an improved systemic recycling model for inhaled soluble uranium. We estimated initial intakes, clearance rates, kidney burdens, and resulting radiation doses to lungs, kidneys, and bone surfaces. 38 refs., 10 figs., 7 tabs.

  3. Method of preparation of uranium nitride

    DOE Patents [OSTI]

    Kiplinger, Jaqueline Loetsch; Thomson, Robert Kenneth James

    2013-07-09T23:59:59.000Z

    Method for producing terminal uranium nitride complexes comprising providing a suitable starting material comprising uranium; oxidizing the starting material with a suitable oxidant to produce one or more uranium(IV)-azide complexes; and, sufficiently irradiating the uranium(IV)-azide complexes to produce the terminal uranium nitride complexes.

  4. URANIUM MILLING ACTIVITIES AT SEQUOYAH FUELS CORPORATION

    E-Print Network [OSTI]

    unknown authors

    Sequoyah Fuels Corporation (SFC) describes previous operations at its Gore, Oklahoma, uranium conversion facility as: (1) the recovery of uranium by concentration and purification processes; and (2) the conversion of concentrated and purified uranium ore into uranium hexafluoride (UF 6), or the reduction of depleted uranium tetrafluoride (UF 4) to UF 6. SFC contends that these

  5. Method for fabricating uranium foils and uranium alloy foils

    DOE Patents [OSTI]

    Hofman, Gerard L. (Downers Grove, IL); Meyer, Mitchell K. (Idaho Falls, ID); Knighton, Gaven C. (Moore, ID); Clark, Curtis R. (Idaho Falls, ID)

    2006-09-05T23:59:59.000Z

    A method of producing thin foils of uranium or an alloy. The uranium or alloy is cast as a plate or sheet having a thickness less than about 5 mm and thereafter cold rolled in one or more passes at substantially ambient temperatures until the uranium or alloy thereof is in the shape of a foil having a thickness less than about 1.0 mm. The uranium alloy includes one or more of Zr, Nb, Mo, Cr, Fe, Si, Ni, Cu or Al.

  6. Mitigation of Hydrogen Gas Generation from the Reaction of Water with Uranium Metal in K Basins Sludge

    SciTech Connect (OSTI)

    Sinkov, Sergey I.; Delegard, Calvin H.; Schmidt, Andrew J.

    2010-01-29T23:59:59.000Z

    Means to decrease the rate of hydrogen gas generation from the chemical reaction of uranium metal with water were identified by surveying the technical literature. The underlying chemistry and potential side reactions were explored by conducting 61 principal experiments. Several methods achieved significant hydrogen gas generation rate mitigation. Gas-generating side reactions from interactions of organics or sludge constituents with mitigating agents were observed. Further testing is recommended to develop deeper knowledge of the underlying chemistry and to advance the technology aturation level. Uranium metal reacts with water in K Basin sludge to form uranium hydride (UH3), uranium dioxide or uraninite (UO2), and diatomic hydrogen (H2). Mechanistic studies show that hydrogen radicals (H·) and UH3 serve as intermediates in the reaction of uranium metal with water to produce H2 and UO2. Because H2 is flammable, its release into the gas phase above K Basin sludge during sludge storage, processing, immobilization, shipment, and disposal is a concern to the safety of those operations. Findings from the technical literature and from experimental investigations with simple chemical systems (including uranium metal in water), in the presence of individual sludge simulant components, with complete sludge simulants, and with actual K Basin sludge are presented in this report. Based on the literature review and intermediate lab test results, sodium nitrate, sodium nitrite, Nochar Acid Bond N960, disodium hydrogen phosphate, and hexavalent uranium [U(VI)] were tested for their effects in decreasing the rate of hydrogen generation from the reaction of uranium metal with water. Nitrate and nitrite each were effective, decreasing hydrogen generation rates in actual sludge by factors of about 100 to 1000 when used at 0.5 molar (M) concentrations. Higher attenuation factors were achieved in tests with aqueous solutions alone. Nochar N960, a water sorbent, decreased hydrogen generation by no more than a factor of three while disodium phosphate increased the corrosion and hydrogen generation rates slightly. U(VI) showed some promise in attenuating hydrogen but only initial testing was completed. Uranium metal corrosion rates also were measured. Under many conditions showing high hydrogen gas attenuation, uranium metal continued to corrode at rates approaching those observed without additives. This combination of high hydrogen attenuation with relatively unabated uranium metal corrosion is significant as it provides a means to eliminate uranium metal by its corrosion in water without the accompanying hazards otherwise presented by hydrogen generation.

  7. Multiple Mechanisms of Uranium Immobilization by Cellulomonas sp. Strain ES6

    SciTech Connect (OSTI)

    Sivaswamy, Vaideeswaran; Boyanov, Maxim I.; Peyton, Brent M.; Viamajala, Sridhar; Gerlach, Robin; Apel, William; Sani, Rajesh K.; Dohnalkova, Alice; Kemner, Kenneth M.; Borch, Thomas

    2011-02-24T23:59:59.000Z

    Removal of hexavalent uranium (U(VI)) from aqueous solution was studied using a Gram-positive facultative anaerobe, Cellulomonas sp. strain ES6, under anaerobic, non-growth conditions in bicarbonate and PIPES buffers. Inorganic phosphate was released by cells during the experiments providing ligands for formation of insoluble U(VI) phosphates. Phosphate release was most probably the result of anaerobic hydrolysis of intracellular polyphosphates accumulated by ES6 during aerobic growth. Microbial reduction of U(VI) to U(IV) was also observed. However, the relative magnitudes of U(VI) removal by abiotic (phosphate-based) precipitation and microbial reduction depended on the buffer chemistry. In bicarbonate buffer, X-ray absorption fine structure (XAFS) spectroscopy showed that U in the solid phase was present primarily as a non-uraninite U(IV) phase, whereas in PIPES buffer, U precipitates consisted primarily of U(VI)-phosphate. In both bicarbonate and PIPES buffer, net release of cellular phosphate was measured to be lower than that observed in U-free controls suggesting simultaneous precipitation of U and PO3-4 . In PIPES, U(VI) phosphates formed a significant portion of U precipitates and mass balance estimates of U and P along with XAFS data corroborate this hypothesis. High-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (EDS) of samples from PIPES treatments indeed showed both extracellular and intracellular accumulation of U solids with nanometer sized lath structures that contained U and P. In bicarbonate, however, more phosphate was removed than required to stoichiometrically balance the U(VI)/U(IV) fraction determined by XAFS, suggesting that U(IV) precipitated together with phosphate in this system. When anthraquinone-2,6-disulfonate (AQDS), a known electron shuttle, was added to the experimental reactors, the dominant removal mechanism in both buffers was reduction to a non-uraninite U(IV) phase. Uranium immobilization by abiotic precipitation or microbial reduction has been extensively reported; however, the present work suggests that strain ES6 can remove U(VI) from solution simultaneously through precipitation with phosphate ligands and microbial reduction, depending on the environmental conditions. Cellulomonadaceae are environmentally relevant subsurface bacteria and here, for the first time, the presence of multiple U immobilization mechanisms within one organism is reported using Cellulomonas sp. strain ES6.

  8. Recovery of uranium from seawater

    SciTech Connect (OSTI)

    Sugasaka, K. (Government Industrial Research Inst., Shikoku, Japan); Katoh, S.; Takai, N.; Takahashi, H.; Umezawa, Y.

    1981-01-01T23:59:59.000Z

    Seawater contains various elements in solution. Deuterium, lithium, and uranium are the important ingredients for energy application at present and in the future. This paper deals with the recovery of uranium from seawater, with emphasis on the development of an adsorbent with high selectivity and rate of adsorption for uranium. Polyacrylamidoxime chelating resins were synthesized from various co-polymers of acrylonitrile and cross-linking agents. The resulting resins with the chelating amidoxime group showed selective adsorption for uranium in seawater. The amount of uranium adsorbed from seawater at room temperature reached 3.2 mg/g resin after 180 days. Polyacrylamidoxime fiber, which was prepared from polyacrylonitrile fiber and hydroxylamine, showed a high rate of adsorption for uranium. The polyacrylamidoxime fiber conditioned with 1 M HC1 and 1 M NaOH adsorbed 4 mg U/g fiber from seawater in ten days. 9 figures, 6 tables.

  9. Disposition of Surplus Highly Enriched Uranium

    Broader source: Energy.gov (indexed) [DOE]

    four alternatives that would eliminate the weapons-usability of HEU by blending it with depleted uranium, natural uranium, or low-enriched uranium (LEU) to create LEU, either as...

  10. Uranium in prehistoric Indian pottery

    E-Print Network [OSTI]

    Filberth, Ernest William

    1976-01-01T23:59:59.000Z

    URANIUM IN PREHISTORIC INDIAN POTTERY A Thesis by ERNEST WILLIAM FILBERTH Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE December 1976 Major Subject...: Chemistry URANIUM IN PREHISTORIC INDIAN POTTERY A Thesis by ERNEST WILLIAM FILBERTH Approved as to style and content by: (Chairman of Committee) (Head of Department) (Member) (Membe (Member) (Member) December 1976 ABSTRACT Uranium in Prehistoric...

  11. anthropogenic uranium enrichments: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Websites Summary: Flats Plutonium and Uranium Weapons-Grade Plutonium Enriched Uranium Depleted Uranium Plutonium-238 0.01 - 0.05% Uranium-234 0.1 - 1.02% Uranium-234...

  12. Disposition of Surplus Highly Enriched Uranium

    Broader source: Energy.gov (indexed) [DOE]

    of Surplus Highly Enriched Uranium Environmental Impact Statement kternationd Atomic Energy Agency Idaho Nationrd Engineering Laborato low-enriched uranium low-level waste...

  13. Uranium Processing Facility Site Readiness Subproject Completed...

    National Nuclear Security Administration (NNSA)

    Field Offices Welcome to the NNSA Production Office NPO News Releases Uranium Processing Facility Site Readiness Subproject Completed ... Uranium Processing Facility Site...

  14. Unexpected, Stable Form of Uranium Detected | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Unexpected, Stable Form of Uranium Detected Unexpected, Stable Form of Uranium Detected Insights on underappreciated reaction could shed light on environmental cleanup options...

  15. Uranium Weapons Components Successfully Dismantled | National...

    National Nuclear Security Administration (NNSA)

    Our Jobs Our Jobs Working at NNSA Blog Home About Us Our History NNSA Timeline Uranium Weapons Components Successfully Dismantled Uranium Weapons Components Successfully...

  16. Adsorptive Stripping Voltammetric Measurements of Trace Uranium...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Adsorptive Stripping Voltammetric Measurements of Trace Uranium at the Bismuth Film Electrode. Adsorptive Stripping Voltammetric Measurements of Trace Uranium at the Bismuth Film...

  17. Uranium Enrichment Decontamination and Decommissioning Fund's...

    Office of Environmental Management (EM)

    Uranium Enrichment Decontamination and Decommissioning Fund's Fiscal Year 2008 and 2007 Financial Statement Audit, OAS-FS-10-05 Uranium Enrichment Decontamination and...

  18. Conversion of depleted uranium hexafluoride to a solid uranium compound

    DOE Patents [OSTI]

    Rothman, Alan B. (Willowbrook, IL); Graczyk, Donald G. (Lemont, IL); Essling, Alice M. (Elmhurst, IL); Horwitz, E. Philip (Naperville, IL)

    2001-01-01T23:59:59.000Z

    A process for converting UF.sub.6 to a solid uranium compound such as UO.sub.2 and CaF. The UF.sub.6 vapor form is contacted with an aqueous solution of NH.sub.4 OH at a pH greater than 7 to precipitate at least some solid uranium values as a solid leaving an aqueous solution containing NH.sub.4 OH and NH.sub.4 F and remaining uranium values. The solid uranium values are separated from the aqueous solution of NH.sub.4 OH and NH.sub.4 F and remaining uranium values which is then diluted with additional water precipitating more uranium values as a solid leaving trace quantities of uranium in a dilute aqueous solution. The dilute aqueous solution is contacted with an ion-exchange resin to remove substantially all the uranium values from the dilute aqueous solution. The dilute solution being contacted with Ca(OH).sub.2 to precipitate CaF.sub.2 leaving dilute NH.sub.4 OH.

  19. Liquid-metal fast-breeder reactors: Preliminary safety and environmental information document. Volume VI

    SciTech Connect (OSTI)

    Not Available

    1980-01-01T23:59:59.000Z

    Information is presented concerning LMFBR design characteristics; uranium-plutonium/uranium recycle homogeneous core; uranium-plutonium/uranium spiked recycle heterogeneous core; uranium-plutonium/uranium spiked recycle homogeneous core; uranium-plutonium/thorium spiked recycle heterogeneous core; uranium-plutonium/thorium spiked recycle homogeneous core; thorium-plutonium/thorium spiked recycle homogeneous core; denatured uranium-233/thorium cycle homogeneous core; safety consideration for the LMFBR; and environmental considerations.

  20. Spatial distribution of an uranium-respiring betaproteobacterium at the rifle, CO field research site

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Koribanics, Nicole M.; Tuorto, Steven J.; Lopez-Chiaffarelli, Nora; McGuinness, Lora R.; Häggblom, Max M.; Williams, Kenneth H.; Long, Philip E.; Kerkhof, Lee J.; Morais, Paula V

    2015-04-13T23:59:59.000Z

    The Department of Energy’s Integrated Field-Scale Subsurface Research Challenge Site (IFRC) at Rifle, Colorado was created to address the gaps in knowledge on the mechanisms and rates of U(VI) bioreduction in alluvial sediments. Previous studies at the Rifle IFRC have linked microbial processes to uranium immobilization during acetate amendment. Several key bacteria believed to be involved in radionuclide containment have been described; however, most of the evidence implicating uranium reduction with specific microbiota has been indirect. Here, we report on the cultivation of a microorganism from the Rifle IFRC that reduces uranium and appears to utilize it as a terminalmore »electron acceptor for respiration with acetate as electron donor. Furthermore, this bacterium constitutes a significant proportion of the subsurface sediment community prior to biostimulation based on TRFLP profiling of 16S rRNA genes. 16S rRNA gene sequence analysis indicates that the microorganism is a betaproteobacterium with a high similarity to Burkholderia fungorum. This is, to our knowledge, the first report of a betaproteobacterium capable of uranium respiration. Our results indicate that this microorganism occurs commonly in alluvial sediments located between 3-6 m below ground surface at Rifle and may play a role in the initial reduction of uranium at the site.« less

  1. Spatial distribution of an uranium-respiring betaproteobacterium at the rifle, CO field research site

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Koribanics, Nicole M. [Rutgers Univ., New Brunswick, NJ (United States); Tuorto, Steven J. [Rutgers Univ., New Brunswick, NJ (United States); Lopez-Chiaffarelli, Nora [Rutgers Univ., New Brunswick, NJ (United States); McGuinness, Lora R. [Rutgers Univ., New Brunswick, NJ (United States); Häggblom, Max M. [Rutgers Univ., New Brunswick, NJ (United States); Williams, Kenneth H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Long, Philip E. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kerkhof, Lee J. [Rutgers Univ., New Brunswick, NJ (United States); Morais, Paula V [Univ. of Coimbra (Portugal)

    2015-04-13T23:59:59.000Z

    The Department of Energy’s Integrated Field-Scale Subsurface Research Challenge Site (IFRC) at Rifle, Colorado was created to address the gaps in knowledge on the mechanisms and rates of U(VI) bioreduction in alluvial sediments. Previous studies at the Rifle IFRC have linked microbial processes to uranium immobilization during acetate amendment. Several key bacteria believed to be involved in radionuclide containment have been described; however, most of the evidence implicating uranium reduction with specific microbiota has been indirect. Here, we report on the cultivation of a microorganism from the Rifle IFRC that reduces uranium and appears to utilize it as a terminal electron acceptor for respiration with acetate as electron donor. Furthermore, this bacterium constitutes a significant proportion of the subsurface sediment community prior to biostimulation based on TRFLP profiling of 16S rRNA genes. 16S rRNA gene sequence analysis indicates that the microorganism is a betaproteobacterium with a high similarity to Burkholderia fungorum. This is, to our knowledge, the first report of a betaproteobacterium capable of uranium respiration. Our results indicate that this microorganism occurs commonly in alluvial sediments located between 3-6 m below ground surface at Rifle and may play a role in the initial reduction of uranium at the site.

  2. Determination of kinetic coefficients for the reduction and removal of uranium from water by the Desulfovibrio desulfuricans bacteria

    SciTech Connect (OSTI)

    Tucker, M.D.; Barton, L.L.; Thomson, B.M. [Sandia National Labs., Albuquerque, NM (United States)

    1996-12-31T23:59:59.000Z

    Uranium contamination of groundwater and surface water from abandoned uranium mill tailings piles is a serious concern in many areas of the western United States. U(VI) is soluble in water and, as a result, is relatively mobile in the environment. U(IV), however, is generally insoluble in water and, therefore, is not subject to aqueous transport. In recent years, researchers have discovered that certain microorganisms, such as the sulfate-reducing bacteria Desuffiovibrio desulfricans, can mediate the reduction of U(VI) to U(IV) by anaerobic respiration. Although the ability of this microorganism to reduce U(VI) has been studied in some detail by previous researchers, the kinetics of the reaction have not been characterized. The purpose of this research was to perform kinetic studies on Desuffiovibrio desulfricans during simultaneous reduction of sulfate and uranium and to determine the mineral phase of uranium after it has been reduced. The studies were conducted in a laboratory-scale chemostat under substrate-limited growth conditions with pyruvate as the substrate. The maximum rate of substrate utilization (k) was determined to be 4.70 days{sup -1} while the half-velocity constant (Ks) was 140 mg CODA. The yield coefficient (Y) was determined to be 0. 17 mg cells/mg COD while the endogenous decay coefficient (kd) was found to be 0.072 days{sup -1}. After reduction, U(IV) precipitated from solution in the uraninite (UO{sub 2}) phase as predicted by thermodynamics. Uranium removal efficiency as high as 90% was achieved in the chemostat.

  3. 2013 Domestic Uranium Production Report

    E-Print Network [OSTI]

    Administration (EIA), the statistical and analytical agency within the U.S. Department of Energy. By law, EIA.S. Energy Information Administration | 2013 Domestic Uranium Production Report iii Preface The U.S. Energy://www.eia.doe.gov/glossary/. #12;U.S. Energy Information Administration | 2013 Domestic Uranium Production Report iv Contents

  4. Behavior of Uranium(VI) during HEDPA Leaching for Aluminum Dissolution in Tank Waste Sludges

    E-Print Network [OSTI]

    Powell, Brian A.; Rao, Linfeng; Nash, Kenneth L.; Martin, Leigh

    2006-01-01T23:59:59.000Z

    Dissolution in Tank Waste Sludges Brian A. Powell 1 ,to produce a clay-like sludge layer, a slurry phase, and anto be concentrated in the sludge phase, which is primarily

  5. Examination of Uranium(VI) Leaching During Ligand Promoted Dissolution of Waste Tank Sludge Surrogates

    E-Print Network [OSTI]

    Powell, Brian A.

    2008-01-01T23:59:59.000Z

    in Hanford waste tank sludge simulants. J. Nucl. Sci.from simulated tank waste sludges. Sep. Sci. Tech. 38(2),Dissolution of Waste Tank Sludge Surrogates. In preparation,

  6. RSONANCE ET RELAXATION DES FLUORS DANS DES FLUORURES COMPLEXES D'URANIUM VI PULVRULENTS (1)

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    lev6e (par exemple pour UF 6' Ámol 2- 110 X 10-6 cgs) ; un important paramagnetisme de Van Vleck va de temperature ambiante. NaF, soigneusement d6shydrat6, est mis dans un reci- pient de Kel-F et UF6 est introduit

  7. Aerobic uranium (VI) bioprecipitation by metal-resistant bacteria isolated from radionuclide-

    E-Print Network [OSTI]

    Skolnick, Jeff

    and other countries. The dis- posal of radioactive waste has traditionally involved underground storage- ment of Energy's (DOE) Oak Ridge Field Research Center (ORFRC), were determined. The ORFRC repre- sents

  8. Multicomponent reactive transport modeling of uranium bioremediation field experiments

    SciTech Connect (OSTI)

    Fang, Yilin; Yabusaki, Steven B.; Morrison, Stan J.; Amonette, James E.; Long, Philip E.

    2009-10-15T23:59:59.000Z

    Biostimulation field experiments with acetate amendment are being performed at a former uranium mill tailings site in Rifle, Colorado, to investigate subsurface processes controlling in situ bioremediation of uranium-contaminated groundwater. An important part of the research is identifying and quantifying field-scale models of the principal terminal electron-accepting processes (TEAPs) during biostimulation and the consequent biogeochemical impacts to the subsurface receiving environment. Integrating abiotic chemistry with the microbially mediated TEAPs in the reaction network brings into play geochemical observations (e.g., pH, alkalinity, redox potential, major ions, and secondary minerals) that the reactive transport model must recognize. These additional constraints provide for a more systematic and mechanistic interpretation of the field behaviors during biostimulation. The reaction network specification developed for the 2002 biostimulation field experiment was successfully applied without additional calibration to the 2003 and 2007 field experiments. The robustness of the model specification is significant in that 1) the 2003 biostimulation field experiment was performed with 3 times higher acetate concentrations than the previous biostimulation in the same field plot (i.e., the 2002 experiment), and 2) the 2007 field experiment was performed in a new unperturbed plot on the same site. The biogeochemical reactive transport simulations accounted for four TEAPs, two distinct functional microbial populations, two pools of bioavailable Fe(III) minerals (iron oxides and phyllosilicate iron), uranium aqueous and surface complexation, mineral precipitation, and dissolution. The conceptual model for bioavailable iron reflects recent laboratory studies with sediments from the Old Rifle Uranium Mill Tailings Remedial Action (UMTRA) site that demonstrated that the bulk (~90%) of Fe(III) bioreduction is associated with the phyllosilicates rather than the iron oxides. The uranium reaction network includes a U(VI) surface complexation model based on laboratory studies with Old Rifle UMTRA sediments and aqueous complexation reactions that include ternary complexes (e.g., calcium-uranyl-carbonate). The bioreduced U(IV), Fe(II), and sulfide components produced during the experiments are strongly associated with the solid phases and may play an important role in long-term uranium immobilization.

  9. Uranium Marketing Annual Report -

    Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 111 1,613 122 40Coal Stocks at Commercial and InstitutionalArea:Mnt(N)3. Deliveries of uranium

  10. Uranium Marketing Annual Report -

    Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 111 1,613 122 40Coal Stocks at Commercial and InstitutionalArea:Mnt(N)3. Deliveries of uranium4.

  11. Uranium Marketing Annual Report -

    Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 111 1,613 122 40Coal Stocks at Commercial and InstitutionalArea:Mnt(N)3. Deliveries2.5.3. Uranium

  12. Single-Cell Imaging and Spectroscopic Analyses of Cr(VI) Reduction on the Surface of Bacterial Cells

    SciTech Connect (OSTI)

    Wang, Yuanmin; Sevinc, Papatya C.; Belchik, Sara M.; Fredrickson, Jim K.; Shi, Liang; Lu, H. Peter

    2013-01-22T23:59:59.000Z

    We investigate single-cell reduction of toxic Cr(VI) by the dissimilatory metal-reducing bacterium Shewanella oneidensis MR-1 (MR-1), an important bioremediation process, using Raman spectroscopy and scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDX). Our experiments indicate that the toxic and highly soluble Cr(VI) can be efficiently reduced to the less toxic and non-soluble Cr2O3 nanoparticles by MR-1. Cr2O3 is observed to emerge as nanoparticles adsorbed on the cell surface and its chemical nature is identified by EDX imaging and Raman spectroscopy. Co-localization of Cr2O3 and cytochromes by EDX imaging and Raman spectroscopy suggests a terminal reductase role for MR-1 surface-exposed cytochromes MtrC and OmcA. Our experiments revealed that the cooperation of surface proteins OmcA and MtrC makes the reduction reaction most efficient, and the sequence of the reducing reactivity of the MR-1 is: wild type > single mutant @mtrC or mutant @omcA > double mutant (@omcA-@mtrC). Moreover, our results also suggest that the direct microbial Cr(VI) reduction and Fe(II) (hematite)-mediated Cr(VI) reduction mechanisms may co-exist in the reduction processes.

  13. Diversity and characterization of sulfate-reducing bacteria in groundwater at a uranium mill tailings site

    SciTech Connect (OSTI)

    Chang, Yun-Juan (Unknown); Peacock, A D. (Tennessee, Univ Of); Long, Philip E. (BATTELLE (PACIFIC NW LAB)); Stephen, John R. (Unknown); McKinley, James P. (BATTELLE (PACIFIC NW LAB)); Mcnaughton, Sarah J. (Unknown); Hussain, A K M A.; Saxton, A M.; White, D C. (Unknown)

    2000-12-01T23:59:59.000Z

    Microbially mediated reduction and immobilization of U(VI) to U(TV) plays a role in both natural attenuation and accelerated bioremediation of uranium contaminated sites. To realize bioremediation potential and accurately predict natural attenuation, it is important to first understand the microbial diversity of such sites. In this paper, the distribution of sulfate-reducing bacteria (SRB) in contaminated groundwater associated with a uranium mill tailings disposal site at Shiprock, N.Mex,, was investigated. Two culture-independent analyses were employed: sequencing of clone libraries of PCR-amplified dissimilatory sulfite reductase (DSR) gene fragments and phospholipid fatty acid (PLFA) biomarker analysis. A remarkable diversity among the DSR sequences was revealed, including sequences from F-Proteobacteria, gram-positive organisms, and the Nitrospira division. PLFA analysis detected at least,52 different mid-chain-branched saturate PLFA and included a high proportion of 10me16:0, Desulfotomaculum and Desulfotomaculum-like sequences were the most dominant DSR genes detected. Those belonging to SRB within F-Proteobacteria were mainly recovered from low-uranium (less than or equal to 302 ppb) samples. One Desulfotomaculum like sequence cluster overwhelmingly dominated high-U (> 1,500 ppb) sites. Logistic regression showed a significant influence of uranium concentration over the dominance of this cluster of sequences (P= 0.0001), This strong association indicates that Desulfotomaculum has remarkable tolerance and adaptation to high levels of uranium and suggests the organism's possible involvement in natural attenuation of uranium. The in situ activity level of Desulfotomaculum in uranium-contaminated environments and its comparison to the activities of other SRB and other functional groups should be an important area for future research.

  14. SHEEP MOUNTAIN URANIUM PROJECT CROOKS GAP, WYOMING

    E-Print Network [OSTI]

    SHEEP MOUNTAIN URANIUM PROJECT CROOKS GAP, WYOMING US EPA Project Meeting April 7 2011April 7, 2011/Titan Uranium, VP Development · Deborah LebowAal/EPA Region 8 Air Program Introduction to Titan Uranium USA;PROJECT OVERVIEW ·Site Location·Site Location ·Fremont , Wyoming ·Existing Uranium Mine Permit 381C

  15. APPENDIX J Partition Coefficients For Uranium

    E-Print Network [OSTI]

    APPENDIX J Partition Coefficients For Uranium #12;Appendix J Partition Coefficients For Uranium J.1.0 Background The review of uranium Kd values obtained for a number of soils, crushed rock and their effects on uranium adsorption on soils are discussed below. The solution pH was also used as the basis

  16. Air quality VI details environmental progress

    SciTech Connect (OSTI)

    NONE

    2007-12-31T23:59:59.000Z

    A report is given of the International Conference on Air Quality VI where key topics discussed were control of mercury, trace elements, sulphur trioxide and particulates. This year a separate track was added on greenhouse gas reduction, with panels on greenhouse gas policy and markets, CO{sub 2} capture and sequestration, and monitoring, mitigation and verification. In keynote remarks, NETL Director Carl Bauer noted that emissions have gone down since 1990 even though coal consumption has increased. The conference provided an overview of the state-of-the-science regarding key pollutants and CO{sub 2}, the corresponding regulatory environment, and the technology readiness of mitigation techniques. 1 photo.

  17. Flyer, Title VI | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33Frequently20,000 RussianBy: Thomas P. D'Agostino, Undersecretary forCITI Briefing.pdfTitles VI and

  18. Microsoft Word - FeVI.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHighandSWPA / SPRA / USACE SWPAURTeC:8CO6 Figure 1. Proposed Fe(VI)-nitrido

  19. Blue Canyon VI | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnualProperty EditCalifornia: EnergyAvignon,Belcher HomesLyonsBirchBlockVI Jump to: navigation,

  20. DarkStar VI | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are beingZealand JumpConceptual Model,DOE Facility Database Data and Resources11-DNADalyDanishDarajatDarien,DarkStar VI

  1. Biomineralization of Uranium by PhoY Phosphatase Activity Aids Cell Survival in Caulobacter crescentus

    SciTech Connect (OSTI)

    Yung, M C [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Jiao, Y [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-07-22T23:59:59.000Z

    Caulobacter crescentus is known to tolerate high levels of uranium [U(VI)], but its detoxification mechanism is poorly understood. Here we show that C. crescentus is able to facilitate U(VI) biomineralization through the formation of U-Pi precipitates via its native alkaline phosphatase activity. The U-Pi precipitates, deposited on the cell surface in the form of meta-autunite structures, have a lower U/Pi ratio than do chemically produced precipitates. The enzyme that is responsible for the phosphatase activity and thus the biomineralization process is identified as PhoY, a periplasmic alkaline phosphatase with broad substrate specificity. Furthermore, PhoY is shown to confer a survival advantage on C. crescentus toward U(VI) under both growth and nongrowth conditions. Results obtained in this study thus highlight U(VI) biomineralization as a resistance mechanism in microbes, which not only improves our understanding of bacterium-mineral interactions but also aids in defining potential ecological niches for metal-resistant bacteria.

  2. The End of Cheap Uranium

    E-Print Network [OSTI]

    Michael Dittmar

    2011-06-21T23:59:59.000Z

    Historic data from many countries demonstrate that on average no more than 50-70% of the uranium in a deposit could be mined. An analysis of more recent data from Canada and Australia leads to a mining model with an average deposit extraction lifetime of 10+- 2 years. This simple model provides an accurate description of the extractable amount of uranium for the recent mining operations. Using this model for all larger existing and planned uranium mines up to 2030, a global uranium mining peak of at most 58 +- 4 ktons around the year 2015 is obtained. Thereafter we predict that uranium mine production will decline to at most 54 +- 5 ktons by 2025 and, with the decline steepening, to at most 41 +- 5 ktons around 2030. This amount will not be sufficient to fuel the existing and planned nuclear power plants during the next 10-20 years. In fact, we find that it will be difficult to avoid supply shortages even under a slow 1%/year worldwide nuclear energy phase-out scenario up to 2025. We thus suggest that a worldwide nuclear energy phase-out is in order. If such a slow global phase-out is not voluntarily effected, the end of the present cheap uranium supply situation will be unavoidable. The result will be that some countries will simply be unable to afford sufficient uranium fuel at that point, which implies involuntary and perhaps chaotic nuclear phase-outs in those countries involving brownouts, blackouts, and worse.

  3. Elucidating Bioreductive Transformations within Physically Complex Media: Impact on the Fate and Transport of Uranium and Chromium

    SciTech Connect (OSTI)

    Scott Fendorf; Chris Francis; Phil Jardine; Shawn Benner

    2009-03-01T23:59:59.000Z

    In situ stabilization (inclusive of natural attenuation) of toxic metals and radionuclides is an attractive approach for remediating many contaminated DOE sites. By immobilizing toxic metals and radionuclides in place, the removal of contaminated water to the surface for treatment as well as the associated disposal costs are avoided. To enhance in situ remediaton, microbiological reductive stabilization of contaminant metals has been, and continues to be, actively explored. It is likely that surface and subsurface microbial activity can alter the redox state of toxic metals and radionuclides, either directly or indirectly, so they are rendered immobile. Furthermore, anaerobic bacterial metabolic products will help to buffer pulses of oxidation, typically from fluxes of nitrate or molecular oxygen, and thus may stabilize reduced contaminants from oxidative mobilization. Uranium and chromium are two elements of particular concern within the DOE complex that, owing to their abundance and toxicity, appear well suited for biologically mediated reductive stabilization. Subsurface microbial activity can alter the redox state of toxic metals and radionuclides, rending them immobile. Imparting an important criterion on the probability that contaminants will undergo reductive stabilization, however, is the chemical and physical heterogeneity of the media. Our research first examined microbially induced transformation of iron (hydr)oxide minerals and their impact on contaminant attenuation. We revealed that in intricate cascade of geochemical reactions is induced by microbially produced Fe(II), and that during transformation contaminants such as U(VI) can be incorporated into the structure, and a set of Fe(II) bearing solids capable of reducing Cr(VI) and stabilizing resulting Cr(III). We also note, however, that common subsurface constituents such as phosphate can modify iron oxide transformation pathways and thus impact contaminant sequestration—affecting both Cr and U stabilization. We extended our work to explore factors controlling the sequestration of uranium in the subsurface, with a particular emphasis on mineralogic and geochemical complexity. We reveal that one of the primary factors controlling uranium reduction, via both biological and chemical pathways, is the aqueous speciation of U(VI). Specifically, ternary calcium-uranyl-carbonato complexes stabilize U(VI) relative to reduction. However, countering the lack of reduction, we note a novel sequestration pathway in which the U(VI), as the uranate ion, is incorporated into the structure of transformation iron oxides; magnetite and goethite, both products of Fe(II) induced transformation of ferrihydrite, harbor appreciable quantities of uranium. In sum, our results provide important information on predicting and potentially controlling the migration of chromium and uranium within the DOE complex.

  4. Interactions of Ionic Liquids with Uranium and its Bioreduction

    SciTech Connect (OSTI)

    Zhang, C.; Francis, A.

    2012-09-18T23:59:59.000Z

    We investigated the influence of ionic liquids (ILs) 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM]{sup +}[PF{sub 6}]{sup -}, N-ethylpyridinium trifluoroacetate [EtPy]{sup +}[CF{sub 3}COO]{sup -} and N-ethylpyridinium tetrafluoroborate [Et-Py]{sup +}[BF{sub 4}]{sup -} on uranium reduction by Clostridium sp. under anaerobic conditions. Potentiometric titration, UV-vis spectrophotometry, LC-MS and EXAFS analyses showed monodentate complexation between uranyl and BF{sub 4}{sup -} PF{sub 6}{sup -}; and bidentate complexation with CF{sub 3}COO{sup -}. Ionic liquids affected the growth of Clostridium sp. as evidenced by decrease in optical density, changes in pH, gas production, and the extent of U(VI) reduction and precipitation of U(IV) from solution. Reduction of U(VI) to U(IV) was observed in the presence of [EtPy][BF{sub 4}] and [BMIM][PF{sub 6}] but not with [EtPy][CF{sub 3}COO].

  5. Safe Operating Procedure SAFETY PROTOCOL: URANIUM

    E-Print Network [OSTI]

    Farritor, Shane

    involve the use of natural or depleted uranium. Natural isotopes of uranium are U-238, U-235 and U-234 (see Table 1 for natural abundances). Depleted uranium contains less of the isotopes: U-235 and U-234. The specific activity of depleted uranium (5.0E-7 Ci/g) is less than that of natural uranium (7.1E-7 Ci

  6. DEPARTMENT OF ENERGY Excess Uranium Management: Effects of DOE...

    Broader source: Energy.gov (indexed) [DOE]

    Excess Uranium Management: Effects of DOE Transfers of Excess Uranium on Domestic Uranium Mining, Conversion, and Enrichment Industries; Request for Information AGENCY: Office of...

  7. Proteogenomic monitoring of Geobacter physiology during stimulated uranium bioremediation

    E-Print Network [OSTI]

    Wilkins, M.J.

    2010-01-01T23:59:59.000Z

    Phillips.  1992.  Bioremediation of  uranium contamination in situ uranium bioremediation.  Microbial Biotechnology 2:genes during in situ bioremediation of uranium?contaminated 

  8. adepleted uranium hexafluoride: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and purified uranium ore into uranium hexafluoride (UF 6), or the reduction of depleted uranium tetrafluoride (UF 4) to UF 6. SFC contends that these unknown authors 15...

  9. active uranium americium: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and purified uranium ore into uranium hexafluoride (UF 6), or the reduction of depleted uranium tetrafluoride (UF 4) to UF 6. SFC contends that these unknown authors 5...

  10. anthropogenic uranium concentration: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and purified uranium ore into uranium hexafluoride (UF 6), or the reduction of depleted uranium tetrafluoride (UF 4) to UF 6. SFC contends that these unknown authors 12...

  11. abandoned uranium mill: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and purified uranium ore into uranium hexafluoride (UF 6), or the reduction of depleted uranium tetrafluoride (UF 4) to UF 6. SFC contends that these unknown authors 3...

  12. anaconda uranium mill: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and purified uranium ore into uranium hexafluoride (UF 6), or the reduction of depleted uranium tetrafluoride (UF 4) to UF 6. SFC contends that these unknown authors 3...

  13. THE THEORY OF URANIUM ENRICHMENT BY THE GAS CENTRIFUGE

    E-Print Network [OSTI]

    Olander, Donald R.

    2013-01-01T23:59:59.000Z

    1979) in "Uranium Enrichment", S. Villani, Ed. , Springer-E. (1973) "Uranium Enrichment by Gas Centrifuge" Mills andTHE THEORY OF URANIUM ENRICHMENT BY THE GAS CENTRIFUGE

  14. Persistence of uranium groundwater plumes: Contrasting mechanisms at two DOE sites in the groundwater-river interaction zone

    SciTech Connect (OSTI)

    Zachara, John M.; Long, Philip E.; Bargar, John; Davis, James A.; Fox, Patricia M.; Fredrickson, Jim K.; Freshley, Mark D.; Konopka, Allan; Liu, Chongxuan; McKinley, James P.; Rockhold, Mark L.; Williams, Kenneth H.; Yabusaki, Steven B.

    2013-04-01T23:59:59.000Z

    We examine subsurface uranium (U) plumes at two U.S. Department of Energy sites that are located near large river systems and that are influenced by groundwater-river hydrologic interaction. Following surface excavation of contaminated materials, both sites were projected to naturally flush remnant uranium contamination to levels below regulatory limits (e.g., 30 µg/L or 0.126 µmol/L; U.S. EPA drinking water standard), with 10 years projected for the Hanford 300 Area (Columbia River) and 12 years for the Rifle site (Colorado River). The rate of observed uranium decrease was much lower than expected at both sites. While uncertainty remains, a comparison of current understanding suggests that the two sites have common, but also different mechanisms controlling plume persistence. At the Hanford 300 A, the persistent source is adsorbed U(VI) in the vadose zone that is released to the aquifer during spring water table excursions. The release of U(VI) from the vadose zone and its transport within the oxic, coarse-textured aquifer sediments is dominated by kinetically-limited surface complexation. Modeling implies that annual plume discharge volumes to the Columbia River are small (< one pore volume). At the Rifle site, slow oxidation of naturally reduced, contaminant U(IV) in the saturated zone and a continuous influx of U(VI) from natural, up-gradient sources influences plume persistence. Rate-limited mass transfer and surface complexation also control U(VI) migration velocity in the sub-oxic Rifle groundwater. Flux of U(VI) from the vadose zone at the Rifle site may be locally important, but it is not the dominant process that sustains the plume. A wide range in microbiologic functional diversity exists at both sites. Strains of Geobacter and other metal reducing bacteria are present at low natural abundance that are capable of enzymatic U(VI) reduction in localized zones of accumulated detrital organic carbon or after organic carbon amendment. Major differences between the sites include the geochemical nature of residual, contaminant U; the rates of current kinetic processes (both biotic and abiotic) influencing U(VI) solid-liquid distribution; the presence of detrital organic matter and the resulting spatial heterogeneity in microbially-driven redox properties; and the magnitude of groundwater hydrologic dynamics controlled by river-stage fluctuations, geologic structures, and aquifer hydraulic properties. The comparative analysis of these sites provides important guidance to the characterization, understanding, modeling, and remediation of groundwater contaminant plumes influenced by surface water interaction that are common world-wide.

  15. KENO-VI Primer: A Primer for Criticality Calculations with SCALE/KENO-VI Using GeeWiz

    SciTech Connect (OSTI)

    Bowman, Stephen M [ORNL

    2008-09-01T23:59:59.000Z

    The SCALE (Standardized Computer Analyses for Licensing Evaluation) computer software system developed at Oak Ridge National Laboratory is widely used and accepted around the world for criticality safety analyses. The well-known KENO-VI three-dimensional Monte Carlo criticality computer code is one of the primary criticality safety analysis tools in SCALE. The KENO-VI primer is designed to help a new user understand and use the SCALE/KENO-VI Monte Carlo code for nuclear criticality safety analyses. It assumes that the user has a college education in a technical field. There is no assumption of familiarity with Monte Carlo codes in general or with SCALE/KENO-VI in particular. The primer is designed to teach by example, with each example illustrating two or three features of SCALE/KENO-VI that are useful in criticality analyses. The primer is based on SCALE 6, which includes the Graphically Enhanced Editing Wizard (GeeWiz) Windows user interface. Each example uses GeeWiz to provide the framework for preparing input data and viewing output results. Starting with a Quickstart section, the primer gives an overview of the basic requirements for SCALE/KENO-VI input and allows the user to quickly run a simple criticality problem with SCALE/KENO-VI. The sections that follow Quickstart include a list of basic objectives at the beginning that identifies the goal of the section and the individual SCALE/KENO-VI features that are covered in detail in the sample problems in that section. Upon completion of the primer, a new user should be comfortable using GeeWiz to set up criticality problems in SCALE/KENO-VI. The primer provides a starting point for the criticality safety analyst who uses SCALE/KENO-VI. Complete descriptions are provided in the SCALE/KENO-VI manual. Although the primer is self-contained, it is intended as a companion volume to the SCALE/KENO-VI documentation. (The SCALE manual is provided on the SCALE installation DVD.) The primer provides specific examples of using SCALE/KENO-VI for criticality analyses; the SCALE/KENO-VI manual provides information on the use of SCALE/KENO-VI and all its modules. The primer also contains an appendix with sample input files.

  16. Laser induced phosphorescence uranium analysis

    DOE Patents [OSTI]

    Bushaw, Bruce A. (Kennewick, WA)

    1986-01-01T23:59:59.000Z

    A method is described for measuring the uranium content of aqueous solutions wherein a uranyl phosphate complex is irradiated with a 5 nanosecond pulse of 425 nanometer laser light and resultant 520 nanometer emissions are observed for a period of 50 to 400 microseconds after the pulse. Plotting the natural logarithm of emission intensity as a function of time yields an intercept value which is proportional to uranium concentration.

  17. Laser induced phosphorescence uranium analysis

    DOE Patents [OSTI]

    Bushaw, B.A.

    1983-06-10T23:59:59.000Z

    A method is described for measuring the uranium content of aqueous solutions wherein a uranyl phosphate complex is irradiated with a 5 nanosecond pulse of 425 nanometer laser light and resultant 520 nanometer emissions are observed for a period of 50 to 400 microseconds after the pulse. Plotting the natural logarithm of emission intensity as a function of time yields an intercept value which is proportional to uranium concentration.

  18. Beneficial Uses of Depleted Uranium

    SciTech Connect (OSTI)

    Brown, C. [U.S. Department of Energy, Germantown, MD (United States); Croff, A.G.; Haire, M. J. [Oak Ridge National Lab., TN (United States)

    1997-08-01T23:59:59.000Z

    Naturally occurring uranium contains 0.71 wt% {sup 235}U. In order for the uranium to be useful in most fission reactors, it must be enriched the concentration of the fissile isotope {sup 235}U must be increased. Depleted uranium (DU) is a co-product of the processing of natural uranium to produce enriched uranium, and DU has a {sup 235}U concentration of less than 0.71 wt%. In the United States, essentially all of the DU inventory is in the chemical form of uranium hexafluoride (UF{sub 6}) and is stored in large cylinders above ground. If this co-product material were to be declared surplus, converted to a stable oxide form, and disposed, the costs are estimated to be several billion dollars. Only small amounts of DU have at this time been beneficially reused. The U.S. Department of Energy (DOE) has begun the Beneficial Uses of DU Project to identify large-scale uses of DU and encourage its reuse for the primary purpose of potentially reducing the cost and expediting the disposition of the DU inventory. This paper discusses the inventory of DU and its rate of increase; DU disposition options; beneficial use options; a preliminary cost analysis; and major technical, institutional, and regulatory issues to be resolved.

  19. Uranium Pyrophoricity Phenomena and Prediction (FAI/00-39)

    SciTech Connect (OSTI)

    PLYS, M.G.

    2000-10-10T23:59:59.000Z

    The purpose of this report is to provide a topical reference on the phenomena and prediction of uranium pyrophoricity for the Hanford Spent Nuclear Fuel (SNF) Project with specific applications to SNF Project processes and situations. Spent metallic uranium nuclear fuel is currently stored underwater at the K basins in the Hanford 100 area, and planned processing steps include: (1) At the basins, cleaning and placing fuel elements and scrap into stainless steel multi-canister overpacks (MCOs) holding about 6 MT of fuel apiece; (2) At nearby cold vacuum drying (CVD) stations, draining, vacuum drying, and mechanically sealing the MCOs; (3) Shipping the MCOs to the Canister Storage Building (CSB) on the 200 Area plateau; and (4) Welding shut and placing the MCOs for interim (40 year) dry storage in closed CSB storage tubes cooled by natural air circulation through the surrounding vault. Damaged fuel elements have exposed and corroded fuel surfaces, which can exothermically react with water vapor and oxygen during normal process steps and in off-normal situations, A key process safety concern is the rate of reaction of damaged fuel and the potential for self-sustaining or runaway reactions, also known as uranium fires or fuel ignition. Uranium metal and one of its corrosion products, uranium hydride, are potentially pyrophoric materials. Dangers of pyrophoricity of uranium and its hydride have long been known in the U.S. Department of Energy (Atomic Energy Commission/DOE) complex and will be discussed more below; it is sufficient here to note that there are numerous documented instances of uranium fires during normal operations. The motivation for this work is to place the safety of the present process in proper perspective given past operational experience. Steps in development of such a perspective are: (1) Description of underlying physical causes for runaway reactions, (2) Modeling physical processes to explain runaway reactions, (3) Validation of the method against experimental data, (4) Application of the method to plausibly explain operational experience, and (5) Application of the method to present process steps to demonstrate process safety and margin. Essentially, the logic above is used to demonstrate that runaway reactions cannot occur during normal SNF Project process steps, and to illustrate the depth of the technical basis for such a conclusion. Some off-normal conditions are identified here that could potentially lead to runaway reactions. However, this document is not intended to provide an exhaustive analysis of such cases. In summary, this report provides a ''toolkit'' of models and approaches for analysis of pyrophoricity safety issues at Hanford, and the technical basis for the recommended approaches. A summary of recommended methods appears in Section 9.0.

  20. Acetate availability and its influence on sustainable bioremediation of uranium-contaminated groundwater

    SciTech Connect (OSTI)

    Williams, Kenneth H.; Long, Philip E.; Davis, James A.; Wilkins, Michael J.; N'Guessan, A. Lucie; Steefel, Carl I.; Yang, Li; Newcomer, Darrell R.; Spane, Frank A.; Kerkhof, L.; McGuinness, L.; Dayvault, Richard; Lovley, Derek

    2011-11-01T23:59:59.000Z

    Field biostimulation experiments at the U.S. Department of Energy's Integrated Field Research Challenge (IFRC) site in Rifle, Colorado, have demonstrated that uranium concentrations in groundwater can be decreased to levels below the U.S. Environmental Protection Agency's (EPA) drinking water standard (0.126 {micro}M). During successive summer experiments - referred to as 'Winchester' (2007) and 'Big Rusty' (2008) - acetate was added to the aquifer to stimulate the activity of indigenous dissimilatory metal-reducing bacteria capable of reductively immobilizing uranium. The two experiments differed in the length of injection (31 vs. 110 days), the maximum concentration of acetate (5 vs. 30 mM), and the extent to which iron reduction ('Winchester') or sulfate reduction ('Big Rusty') was the predominant metabolic process. In both cases, rapid removal of U(VI) from groundwater occurred at calcium concentrations (6 mM) and carbonate alkalinities (8 meq/L) where Ca-UO2-CO3 ternary complexes constitute >90% of uranyl species in groundwater. Complete consumption of acetate and increased alkalinity (>30 meq/L) accompanying the onset of sulfate reduction corresponded to temporary increases in U(VI); however, by increasing acetate concentrations in excess of available sulfate (10 mM), low U(VI) concentrations (0.1-0.05 {micro}M) were achieved for extended periods of time (>140 days). Uniform delivery of acetate during 'Big Rusty' was impeded due to decreases in injection well permeability, likely resulting from biomass accumulation and carbonate and sulfide mineral precipitation. Such decreases were not observed during the short-duration 'Winchester' experiment. Terminal restriction fragment length polymorphism (TRFLP) analysis of 16S rRNA genes demonstrated that Geobacter sp. and Geobacter-like strains dominated the groundwater community profile during iron reduction, with 13C stable isotope probing (SIP) results confirming these strains were actively utilizing acetate to replicate their genome during the period of optimal U(VI) removal. Gene transcript levels during 'Big Rusty' were quantified for Geobacter-specific citrate synthase (gltA), with ongoing transcription during sulfate reduction indicating that members of the Geobacteraceae were still active and likely contributing to U(VI) removal. The persistence of reducible Fe(III) in sediments recovered from an area of prolonged (110 day) sulfate reduction is consistent with this conclusion. These results indicate that acetate availability and its ability to sustain the activity of iron- and uranyl-respiring Geobacter strains during sulfate reduction exerts a primary control on optimized U(VI) removal from groundwater at the Rifle IFRC site over extended timescales (>50 days).

  1. Standard Test Method for Determination of Uranium, Oxygen to Uranium (O/U), and Oxygen to Metal (O/M) in Sintered Uranium Dioxide and Gadolinia-Uranium Dioxide Pellets by Atmospheric Equilibration

    E-Print Network [OSTI]

    American Society for Testing and Materials. Philadelphia

    2007-01-01T23:59:59.000Z

    Standard Test Method for Determination of Uranium, Oxygen to Uranium (O/U), and Oxygen to Metal (O/M) in Sintered Uranium Dioxide and Gadolinia-Uranium Dioxide Pellets by Atmospheric Equilibration

  2. Influence of Reactive Transport on the Reduction of U(VI) in the Presence of Fe(III) and Nitrate: Implications for U(VI) Immobilization by Bioremediation / Biobarriers- Final Report

    SciTech Connect (OSTI)

    B.D. Wood

    2007-01-01T23:59:59.000Z

    Subsurface contamination by metals and radionuclides represent some of the most challenging remediation problems confronting the Department of Energy (DOE) complex. In situ remediation of these contaminants by dissimilatory metal reducing bacteria (DMRB) has been proposed as a potential cost effective remediation strategy. The primary focus of this research is to determine the mechanisms by which the fluxes of electron acceptors, electron donors, and other species can be controlled to maximize the transfer of reductive equivalents to the aqueous and solid phases. The proposed research is unique in the NABIR portfolio in that it focuses on (i) the role of flow and transport in the initiation of biostimulation and the successful sequestration of metals and radionuclides [specifically U(VI)], (ii) the subsequent reductive capacity and stability of the reduced sediments produced by the biostimulation process, and (iii) the potential for altering the growth of biomass in the subsurface by the addition of specific metabolic uncoupling compounds. A scientifically-based understanding of these phenomena are critical to the ability to design successful bioremediation schemes. The laboratory research will employ Shewanella putrefaciens (CN32), a facultative DMRB that can use Fe(III) oxides as a terminal electron acceptor. Sediment-packed columns will be inoculated with this organism, and the reduction of U(VI) by the DMRB will be stimulated by the addition of a carbon and energy source in the presence of Fe(III). Separate column experiments will be conducted to independently examine: (1) the importance of the abiotic reduction of U(VI) by biogenic Fe(II); (2) the influence of the transport process on Fe(III) reduction and U(VI) immobilization, with emphasis on methods for controlling the fluxes of aqueous species to maximize uranium reduction; (3) the reductive capacity of biologically-reduced sediments (with respect to re-oxidation by convective fluxes of O2 and NO3-) and the long-term stability of immobilized uranium mineral phases after bioremediation processes are complete, and (4) the ability for metabolic uncoupling compounds to maintain microbial growth while limiting biomass production. The results of the laboratory experiments will be used to develop mathematical descriptive models for the coupled transport and reduction processes.

  3. Bioreduction and immobilization of uranium in situ: a case study at a USA Department of Energy radioactive waste site, Oak Ridge, Tennessee

    SciTech Connect (OSTI)

    Wu, Weimin [Stanford University; Carley, Jack M [ORNL; Watson, David B [ORNL; Gu, Baohua [ORNL; Brooks, Scott C [ORNL; Kelly, Shelly D [Argonne National Laboratory (ANL); Kemner, Kenneth M [Argonne National Laboratory (ANL); Van Nostrand, Joy [University of Oklahoma, Norman; Wu, Liyou [University of Oklahoma, Norman; Zhou, Jizhong [University of Oklahoma, Norman; Luo, Jian [Georgia Institute of Technology; Cardenas, Erick [Michigan State University, East Lansing; Fields, Matthew Wayne [Miami University, Oxford, OH; Marsh, Terence [Michigan State University, East Lansing; Tiedje, James [Michigan State University, East Lansing; Green, Stefan [Florida State University; Kostka, Joel [Florida State University; Kitanidis, Peter K. [Stanford University; Jardine, Philip [University of Tennessee, Knoxville (UTK); Criddle, Craig [Stanford University

    2011-01-01T23:59:59.000Z

    Bioremediation of uranium contaminated groundwater was tested by delivery of ethanol as an electron donor source to stimulate indigenous microbial bioactivity for reduction and immobilization of uranium in situ, followed by tests of stability of uranium sequestration in the bioreduced area via delivery of dissolved oxygen or nitrate at the US Department of energy's Integrated Field Research Challenge site located at Oak Ridge, Tennessee, USA. After long term treatment that spanned years, uranium in groundwater was reduced from 40-60 mg {center_dot} L{sup -1} to <0.03 mg {center_dot} L{sup -1}, below the USA EPA standard for drinking water. The bioreduced uranium was stable under anaerobic or anoxic conditions, but addition of DO and nitrate to the bioreduced zone caused U remobilization. The change in the microbial community and functional microorganisms related to uranium reduction and oxidation were characterized. The delivery of ethanol as electron donor stimulated the activities of indigenous microorganisms for reduction of U(VI) to U(IV). Results indicated that the immobilized U could be partially remobilized by D0 and nitrate via microbial activity. An anoxic environmental condition without nitrate is essential to maintain the stability of bioreduced uranium.

  4. Process for alloying uranium and niobium

    SciTech Connect (OSTI)

    Holcombe, C.E.; Northcutt, W.G.; Masters, D.R.; Chapman, L.R.

    1990-12-31T23:59:59.000Z

    Alloys such as U-6Nb are prepared by forming a stacked sandwich array of uranium sheets and niobium powder disposed in layers between the sheets, heating the array in a vacuum induction melting furnace to a temperature such as to melt the uranium, holding the resulting mixture at a temperature above the melting point of uranium until the niobium dissolves in the uranium, and casting the uranium-niobium solution. Compositional uniformity in the alloy product is enabled by use of the sandwich structure of uranium sheets and niobium powder.

  5. Process for alloying uranium and niobium

    SciTech Connect (OSTI)

    Holcombe, C.E.; Northcutt, W.G.; Masters, D.R.; Chapman, L.R.

    1991-04-09T23:59:59.000Z

    This patent describes alloys such as U-6Nb prepared by forming a stacked sandwich array of uranium sheets and niobium powder disposed in layers between the sheets, heating the array in a vacuum induction melting furnace to a temperature such as to melt the uranium, holding the resulting mixture at a temperature above the melting point of uranium until the niobium dissolves in the uranium, and casting the uranium-niobium solution. Compositional uniformity in the alloy product is enabled by use of the sandwich structure of uranium sheets and niobium powder.

  6. Characterization of Alpha-Phase Sintering of Uranium and Uranium-Zirconium Alloys for Advanced Nuclear Fuel Applications 

    E-Print Network [OSTI]

    Helmreich, Grant

    2012-02-14T23:59:59.000Z

    The sintering behavior of uranium and uranium-zirconium alloys in the alpha phase were characterized in this research. Metal uranium powder was produced from pieces of depleted uranium metal acquired from the Y-12 plant via hydriding...

  7. Characterization of Alpha-Phase Sintering of Uranium and Uranium-Zirconium Alloys for Advanced Nuclear Fuel Applications

    E-Print Network [OSTI]

    Helmreich, Grant

    2012-02-14T23:59:59.000Z

    The sintering behavior of uranium and uranium-zirconium alloys in the alpha phase were characterized in this research. Metal uranium powder was produced from pieces of depleted uranium metal acquired from the Y-12 plant via hydriding...

  8. Variably Saturated Flow and Multicomponent Biogeochemical Reactive Transport Modeling of a Uranium Bioremediation Field Experiment

    SciTech Connect (OSTI)

    Yabusaki, Steven B.; Fang, Yilin; Williams, Kenneth H.; Murray, Christopher J.; Ward, Anderson L.; Dayvault, Richard; Waichler, Scott R.; Newcomer, Darrell R.; Spane, Frank A.; Long, Philip E.

    2011-11-01T23:59:59.000Z

    Field experiments at a former uranium mill tailings site have identified the potential for stimulating indigenous bacteria to catalyze the conversion of aqueous uranium in the +6 oxidation state to immobile solid-associated uranium in the +4 oxidation state. This effectively removes uranium from solution resulting in groundwater concentrations below actionable standards. Three-dimensional, coupled variably-saturated flow and biogeochemical reactive transport modeling of a 2008 in situ uranium bioremediation field experiment is used to better understand the interplay of transport rates and biogeochemical reaction rates that determine the location and magnitude of key reaction products. A comprehensive reaction network, developed largely through previous 1-D modeling studies, was used to simulate the impacts on uranium behavior of pulsed acetate amendment, seasonal water table variation, spatially-variable physical (hydraulic conductivity, porosity) and geochemical (reactive surface area) material properties. A principal challenge is the mechanistic representation of biologically-mediated terminal electron acceptor process (TEAP) reactions whose products significantly alter geochemical controls on uranium mobility through increases in pH, alkalinity, exchangeable cations, and highly reactive reduction products. In general, these simulations of the 2008 Big Rusty acetate biostimulation field experiment in Rifle, Colorado confirmed previously identified behaviors including (1) initial dominance by iron reducing bacteria that concomitantly reduce aqueous U(VI), (2) sulfate reducing bacteria that become dominant after {approx}30 days and outcompete iron reducers for the acetate electron donor, (3) continuing iron-reducer activity and U(VI) bioreduction during dominantly sulfate reducing conditions, and (4) lower apparent U(VI) removal from groundwater during dominantly sulfate reducing conditions. New knowledge on simultaneously active metal and sulfate reducers has been incorporated into the modeling. In this case, an initially small population of slow growing sulfate reducers is active from the initiation of biostimulation. Three-dimensional, variably saturated flow modeling was used to address impacts of a falling water table during acetate injection. These impacts included a significant reduction in aquifer saturated thickness and isolation of residual reactants and products, as well as unmitigated uranium, in the newly unsaturated vadose zone. High permeability sandy gravel structures resulted in locally high flow rates in the vicinity of injection wells that increased acetate dilution. In downgradient locations, these structures created preferential flow paths for acetate delivery that enhanced local zones of TEAP reactivity and subsidiary reactions. Conversely, smaller transport rates associated with the lower permeability lithofacies (e.g., fine) and vadose zone were shown to limit acetate access and reaction. Once accessed by acetate, however, these same zones limited subsequent acetate dilution and provided longer residence times that resulted in higher concentrations of TEAP products when terminal electron donors and acceptors were not limiting. Finally, facies-based porosity and reactive surface area variations were shown to affect aqueous uranium concentration distributions; however, the ranges were sufficiently small to preserve general trends. Large computer memory and high computational performance were required to simulate the detailed coupled process models for multiple biogeochemical components in highly resolved heterogeneous materials for the 110-day field experiment and 50 days of post-biostimulation behavior. In this case, a highly-scalable subsurface simulator operating on 128 processor cores for 12 hours was used to simulate each realization. An equivalent simulation without parallel processing would have taken 60 days, assuming sufficient memory was available.

  9. Standard practice for removal of uranium or plutonium, or both, for impurity assay in uranium or plutonium materials

    E-Print Network [OSTI]

    American Society for Testing and Materials. Philadelphia

    2006-01-01T23:59:59.000Z

    Standard practice for removal of uranium or plutonium, or both, for impurity assay in uranium or plutonium materials

  10. Reduction and Reoxidation of Soils During & After Uranium Bioremediation; Implications for Long-Term Uraninite Stability & Bioremediation Scheme Implementation

    SciTech Connect (OSTI)

    Jaffe, Peter R.

    2005-06-01T23:59:59.000Z

    This research focuses on the conditions and rates under which uranium will be remobilized after it has been precipitated biologically, and what alterations can be implemented to increase its long-term stability in groundwater after the injection of an electron donor has been discontinued. Furthermore, this research addresses short-term iron reoxidation as a mechanism to enhance/extend uranium bioremediation under iron reduction, without its remobilization. The research to date has focused on long term column experiments involving the biological removal of uranium from groundwater under iron and sulfate reducing conditions. Aquifer sediment was collected from the background area of the Old Rifle UMTRA site and dried and sieved (<2 mm) before being packed into four 15 cm long x 5 cm diameter glass columns. The initial porosity of each column ranged from 0.33 to 0.40. Prior to biostimulation of the columns, 30 mM bicarbonate (purged with CO2/N2 gas, 20:80 ratio) was pumped through the columns to flush out the natural uranium present in the sediment. After the natural uranium was flushed out of the system, 20 uM of uranyl acetate was added to the 30 mM bicarbonate influent media. The column was operated for 11 days to ensure that the effluent U(VI) concentration was equal to the influent U(VI) concentration (no removal of U(VI) occurred before biostimulation). The start of the biostimulation experiment was facilitated by the addition of one pore volume of a growth culture containing the Fe(III) and U(VI) reducing microorganism, Geobacter metallireducens. Flow to the columns was suspended for 24 hours, after which pumping was resumed with acetate (2.8-3.0 mM), as well as trace vitamins and minerals, supplied to the feed media. The columns were operated at 22 +/- 1 degrees C, upright and under up-flow conditions at a rate of 0.2 ml/min (equivalent to a linear groundwater travel time of approximately 135 m/yr). Water samples from column inlets and outlets were collected and analyzed for acetate, U(VI), Fe(II), Br-, NO3- and SO42-. Iron reduction and U(VI) removal was detected in all four columns after three days of column operation with acetate in the inflow. The Fe(II) concentration at the effluent of the columns increased at a rate of 16.6 (+/-1.9) uM/d until leveling off after 10 days of column operation. The pseudo steady-state Fe(II) concentration at the effluent for each column ranged 130 uM to 170 uM. Uranium removal reached steady-state conditions after approximately 23 days of column operation with removal of between 58% to 77% of the initial 20 uM U(VI) added at the influent of the column.

  11. Depleted uranium disposal options.

    SciTech Connect (OSTI)

    Biwer, B. M.; Ranek, N. L.; Goldberg, M.; Avci, H. I.

    2000-04-01T23:59:59.000Z

    Depleted uranium hexafluoride (UF{sub 6}) has been produced in the United States since the 1940s as part of both the military program and the civilian nuclear energy program. The U.S. Department of Energy (DOE) is the agency responsible for managing most of the depleted UF{sub 6} that has been produced in the United States. The total quantity of depleted UF{sub 6} that DOE has to or will have to manage is approximately 700,000 Mg. Studies have been conducted to evaluate the various alternatives for managing this material. This paper evaluates and summarizes the alternative of disposal as low-level waste (LLW). Results of the analysis indicate that UF{sub 6} needs to be converted to a more stable form, such as U{sub 3}O{sub 8}, before disposal as LLW. Estimates of the environmental impacts of disposal in a dry environment are within the currently applicable standards and regulations. Of the currently operating LLW disposal facilities, available information indicates that either of two DOE facilities--the Hanford Site or the Nevada Test Site--or a commercial facility--Envirocare of Utah--would be able to dispose of up to the entire DOE inventory of depleted UF{sub 6}.

  12. Uranium 2007 resources, production and demand

    E-Print Network [OSTI]

    Organisation for Economic Cooperation and Development. Paris

    2008-01-01T23:59:59.000Z

    Based on official information received from 40 countries, Uranium 2007 provides a comprehensive review of world uranium supply and demand as of 1st January 2007, as well as data on global uranium exploration, resources, production and reactor-related requirements. It provides substantive new information from major uranium production centres in Africa, Australia, Central Asia, Eastern Europe and North America. Projections of nuclear generating capacity and reactor-related uranium requirements through 2030 are also featured, along with an analysis of long-term uranium supply and demand issues. It finds that with rising demand and declining inventories, uranium prices have increased dramatically in recent years. As a result, the uranium industry is undergoing a significant revival, bringing to an end a period of over 20 years of underinvestment.

  13. A uranium-titanium-niobium alloy

    SciTech Connect (OSTI)

    Ludtka, G.M.; Ludtka, G.M.

    1990-02-23T23:59:59.000Z

    A uranium alloy having small additions of Ti and Nb shows improved strength and ductility in cross section of greater than one inch over prior uranium alloy having only Ti as an alloying element.

  14. Inherently safe in situ uranium recovery

    DOE Patents [OSTI]

    Krumhansl, James L; Brady, Patrick V

    2014-04-29T23:59:59.000Z

    An in situ recovery of uranium operation involves circulating reactive fluids through an underground uranium deposit. These fluids contain chemicals that dissolve the uranium ore. Uranium is recovered from the fluids after they are pumped back to the surface. Chemicals used to accomplish this include complexing agents that are organic, readily degradable, and/or have a predictable lifetime in an aquifer. Efficiency is increased through development of organic agents targeted to complexing tetravalent uranium rather than hexavalent uranium. The operation provides for in situ immobilization of some oxy-anion pollutants under oxidizing conditions as well as reducing conditions. The operation also artificially reestablishes reducing conditions on the aquifer after uranium recovery is completed. With the ability to have the impacted aquifer reliably remediated, the uranium recovery operation can be considered inherently safe.

  15. Uranium Acquisition | Y-12 National Security Complex

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of Interest (EOI) to acquire up to 6,800 metric tons of Uranium (MTU) of high purity depleted uranium metal (DU) and related material and services. This request for EOI does...

  16. Uranium Bioreduction Rates across Scales: Biogeochemical Hot Moments and Hot Spots during a Biostimulation Experiment at Rifle, Colorado

    SciTech Connect (OSTI)

    Bao, Chen; Wu, Hongfei; Li, Li; Newcomer, Darrell R.; Long, Philip E.; Williams, Kenneth H.

    2014-09-02T23:59:59.000Z

    We aim to understand the scale-dependent evolution of uranium bioreduction during a field experiment at a former uranium mill site near Rifle, Colorado. Acetate was injected to stimulate Fe-reducing bacteria (FeRB) and to immobilize aqueous U(VI) to insoluble U(IV). Bicarbonate was coinjected in half of the domain to mobilize sorbed U(VI). We used reactive transport modeling to integrate hydraulic and geochemical data and to quantify rates at the grid block (0.25 m) and experimental field scale (tens of meters). Although local rates varied by orders of magnitude in conjunction with biostimulation fronts propagating downstream, field-scale rates were dominated by those orders of magnitude higher rates at a few selected hot spots where Fe(III), U(VI), and FeRB were at their maxima in the vicinity of the injection wells. At particular locations, the hot moments with maximum rates negatively corresponded to their distance from the injection wells. Although bicarbonate injection enhanced local rates near the injection wells by a maximum of 39.4%, its effect at the field scale was limited to a maximum of 10.0%. We propose a rate-versus-measurement-length relationship (log R' = -0.63

  17. D Riso-R-429 Automated Uranium

    E-Print Network [OSTI]

    -induced delayed-neutron coun- ting is applied preferably in large geochemical exploration pro- grammes. UraniumCM i D Riso-R-429 Automated Uranium Analysis by Delayed-Neutron Counting H. Kunzendorf, L. Løvborg AUTOMATED URANIUM ANALYSIS BY DELAYED-NEUTRON COUNTING H. Kunzendorf, L. Løvborg and E.M. Christiansen

  18. High strength uranium-tungsten alloys

    DOE Patents [OSTI]

    Dunn, Paul S. (Santa Fe, NM); Sheinberg, Haskell (Los Alamos, NM); Hogan, Billy M. (Los Alamos, NM); Lewis, Homer D. (Bayfield, CO); Dickinson, James M. (Los Alamos, NM)

    1991-01-01T23:59:59.000Z

    Alloys of uranium and tungsten and a method for making the alloys. The amount of tungsten present in the alloys is from about 4 wt % to about 35 wt %. Tungsten particles are dispersed throughout the uranium and a small amount of tungsten is dissolved in the uranium.

  19. High strength uranium-tungsten alloy process

    DOE Patents [OSTI]

    Dunn, Paul S. (Santa Fe, NM); Sheinberg, Haskell (Los Alamos, NM); Hogan, Billy M. (Los Alamos, NM); Lewis, Homer D. (Bayfield, CO); Dickinson, James M. (Los Alamos, NM)

    1990-01-01T23:59:59.000Z

    Alloys of uranium and tungsten and a method for making the alloys. The amount of tungsten present in the alloys is from about 4 wt % to about 35 wt %. Tungsten particles are dispersed throughout the uranium and a small amount of tungsten is dissolved in the uranium.

  20. Uranium Watch REGULATORY CONFUSION: FEDERALAND STATE

    E-Print Network [OSTI]

    Uranium Watch Report REGULATORY CONFUSION: FEDERALAND STATE ENFORCEMENT OF 40 C.F.R. PART 61 SUBPART W INTRODUCTION 1. This Uranium Watch Report, Regulatory Confusion: Federal and State Enforcement at the White Mesa Uranium Mill, San Juan County, Utah. 2. The DAQ, a Division of the Utah Department

  1. Clean Air Act Requirements: Uranium Mill Tailings

    E-Print Network [OSTI]

    EPA'S Clean Air Act Requirements: Uranium Mill Tailings Radon Emissions Rulemaking Reid J. Rosnick requirements for operating uranium mill tailings (Subpart W) Status update on Subpart W activities Outreach/Communications #12;3 EPA Regulatory Requirements for Operating Uranium Mill Tailings (Clean Air Act) · 40 CFR 61

  2. URANIUM MILL TAILINGS RADON FLUX CALCULATIONS

    E-Print Network [OSTI]

    URANIUM MILL TAILINGS RADON FLUX CALCULATIONS PIÃ?ON RIDGE PROJECT MONTROSE COUNTY, COLORADO Inc. (Golder) was commissioned by EFRC to evaluate the operations of the uranium mill tailings storage in this report were conducted using the WISE Uranium Mill Tailings Radon Flux Calculator, as updated on November

  3. RETENTION AND CHEMICAL SPECIATION OF URANIUM IN A WETLAND ON THE SAVANNAH RIVER SITE

    SciTech Connect (OSTI)

    Li, D.; CHANG, H.: SEAMAN, J.; Jaffe, P.; Groos, P.; Jiang, D.; Chen, N.; Lin, J.; Arthur, Z.; Scheckel, K.; Kaplan, D.

    2013-06-17T23:59:59.000Z

    Uranium speciation and retention mechanism onto Savannah River Site (SRS) wetland sediments was studied using batch (ad)sorption experiments, sequential extraction desorption tests and U L{sub 3}-edge X-ray absorption near-edge structure (XANES) spectroscopy of contaminated wetland sediments. U was highly retained by the SRS wetland sediments. In contrast to other similar but much lower natural organic matter (NOM) sediments, significant sorption of U onto the SRS sediments was observed at pH <4 and pH >8. Sequential extraction tests indicated that the U(VI) species were primarily associated with the acid soluble fraction (weak acetic acid extractable) and NOM fraction (Na-pyrophosphate extractable). Uranium L3- edge XANES spectra of the U-retained sediments were nearly identical to that of uranyl acetate. The primary oxidation state of U in these sediments was as U(VI), and there was little evidence that the high sorptive capacity of the sediments could be ascribed to abiotic or biotic reduction to the less soluble U(IV) species. The molecular mechanism responsible for the high U retention in the SRS wetland sediments is likely related to the chemical bonding of U to organic carbon.

  4. Effects of organic carbon supply rates on mobility of previously bioreduced uranium in a contaminated sediment

    SciTech Connect (OSTI)

    Wan, J.; Tokunaga, T.K.; Kim, Y.; Brodie, E.; Daly, R.; Hazen, T.C.; Firestone, M.K.

    2008-05-15T23:59:59.000Z

    Bioreduction-based strategies for remediating uranium (U)-contaminated sediments face the challenge of maintaining the reduced status of U for long times. Because groundwater influxes continuously bring in oxidizing terminal electron acceptors (O{sub 2}, NO{sub 3}{sup -}), it is necessary to continue supplying organic carbon (OC) to maintain the reducing environment after U bioreduction is achieved. We tested the influence of OC supply rates on mobility of previously microbial reduced uranium U(IV) in contaminated sediments. We found that high degrees of U mobilization occurred when OC supply rates were high, and when the sediment still contained abundant Fe(III). Although 900 days with low levels of OC supply minimized U mobilization, the sediment redox potential increased with time as did extractable U(VI) fractions. Molecular analyses of total microbial activity demonstrated a positive correlation with OC supply and analyses of Geobacteraceae activity (RT-qPCR of 16S rRNA) indicated continued activity even when the effluent Fe(II) became undetectable. These data support our earlier hypothesis on the mechanism responsible for re-oxidation of microbial reduced U(IV) under reducing conditions; that microbial respiration caused increased (bi)carbonate concentrations and formation of stable uranyl carbonate complexes, thereby shifted U(IV)/U(VI) equilibrium to more reducing potentials. The data also suggested that low OC concentrations could not sustain the reducing condition of the sediment for much longer time.

  5. Identification of simultaneous U(VI) sorption complexes and U...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    conditions under which U (VI)-CO3-Ca complexes inhibit U reduction. Citation: Singer DM, SME Chatman, ES Ilton, KM Rosso, JF Banfield, and G Waychunas.2012."Identification of...

  6. Building on lessons learned : too high hopes without HOPE VI?

    E-Print Network [OSTI]

    Wang, Kristen J

    2006-01-01T23:59:59.000Z

    By providing substantial grants to public housing authorities to demolish and rebuild distressed public housing and provide services to public housing residents, the HOPE VI program has helped transform these developments ...

  7. Chromium(VI) Reduction by Hydrogen Sulfide in Aqueous

    E-Print Network [OSTI]

    Deng, Baolin

    experiments with excess [Cr(VI)] over [H2S]T indicated that the molar amount of sulfide required for the reduction of 1 M Cr(VI) was 1.5, suggesting the following stoichi- ometry: 2CrO4 2- + 3H2S + 4H+ f 2Cr(OH)3 of fully protonated sulfide (H2S) in the pH range of 6.5-10. The nature of buffers did not influence

  8. Uranium mill tailings and radon

    SciTech Connect (OSTI)

    Hanchey, L A

    1981-01-01T23:59:59.000Z

    The major health hazard from uranium mill tailings is presumed to be respiratory cancer resulting from the inhalation of radon daughter products. A review of studies on inhalation of radon and its daughters indicates that the hazard from the tailings is extremely small. If the assumptions used in the studies are correct, one or two people per year in the US may develop cancer as a result of radon exhaled from all the Uranium Mill Tailings Remedial Action Program sites. The remedial action should reduce the hazard from the tailings by a factor of about 100.

  9. Fire testing of bare uranium hexafluoride cylinders

    SciTech Connect (OSTI)

    Pryor, W.A. [PAI Corp., Oak Rige, TN (United States)

    1991-12-31T23:59:59.000Z

    In 1965, the Oak Ridge Gaseous Diffusion Plant (ORGDP), now the K-25 Site, conducted a series of tests in which bare cylinders of uranium hexafluoride (UF{sub 6}) were exposed to engulfing oil fires for the US Atomic Energy Commission (AEC), now the US Department of Energy (DOE). The tests are described and the results, conclusions, and observations are presented. Two each of the following types of cylinders were tested: 3.5-in.-diam {times} 7.5-in.-long cylinders of Monel (Harshaw), 5.0-in.-diam {times} 30-in.-long cylinders of Monel, and 8-in.-diam {times} 48-in.-long cylinders of nickel. The cylinders were filled approximately to the standard UF{sub 6} fill limits of 5, 55, and 250 lb, respectively, with a U-235 content of 0.22%. The 5-in.- and 8-in.-diam cylinders were tested individually with and without their metal valve covers. For the 3.5-in.-diam Harshaw cylinders and the 5.0-in.-diam cylinder without a valve cover the valves failed and UF{sub 6} was released. The remaining cylinders ruptured explosively in time intervals ranging from about 8.5 to 11 min.

  10. Fire testing of bare uranium hexafluoride cylinders

    SciTech Connect (OSTI)

    Pryor, W.A. [PAI Corp., Oak Ridge, TN (United States)

    1991-12-31T23:59:59.000Z

    In 1965, the Oak Ridge Gaseous Diffusion Plant (ORGDP), now the K-25 Site, conducted a series of tests in which bare cylinders of uranium hexafluoride (UF{sub 6}) were exposed to engulfing oil fires for the US Atomic Energy Commission (AEC), now the US Department of Energy (DOE). The tests are described and the results, conclusions, and observations are presented. Two each of the following types of cylinders were tested: 3.5-in.-diam {times} 7.5-in.-long cylinders of Monel (Harshaw), 5.0-in.-diam {times} x 30-in.-long cylinders of Monel, and 8-in.-diam {times} 48-in.-long cylinders of nickel. The cylinders were filled approximately to the standard UF{sub 6} fill limits of 5, 55, and 250 lb, respectively, with a U-235 content of 0.22%. The 5-in.- and 8-in.-diam cylinders were tested individually with and without their metal valve covers. For the 3.5-in.-diam Harshaw cylinders and the 5.0-in.-diam cylinder without a valve cover, the valves failed and UF{sub 6} was released. The remaining 6 cylinders ruptured explosively in time intervals ranging from about 8.5 to 11 min.

  11. An analysis of uranium dispersal and health effects using a Gulf War case study.

    SciTech Connect (OSTI)

    Marshall, Albert Christian

    2005-07-01T23:59:59.000Z

    The study described in this report used mathematical modeling to estimate health risks from exposure to depleted uranium (DU) during the 1991 Gulf War for both U.S. troops and nearby Iraqi civilians. The analysis found that the risks of DU-induced leukemia or birth defects are far too small to result in an observable increase in these health effects among exposed veterans or Iraqi civilians. Only a few veterans in vehicles accidentally struck by U.S. DU munitions are predicted to have inhaled sufficient quantities of DU particulate to incur any significant health risk (i.e., the possibility of temporary kidney damage from the chemical toxicity of uranium and about a 1% chance of fatal lung cancer). The health risk to all downwind civilians is predicted to be extremely small. Recommendations for monitoring are made for certain exposed groups. Although the study found fairly large calculational uncertainties, the models developed and used are generally valid. The analysis was also used to assess potential uranium health hazards for workers in the weapons complex. No illnesses are projected for uranium workers following standard guidelines; nonetheless, some research suggests that more conservative guidelines should be considered.

  12. Lung cancer in uranium miners: A tissue resource and pilot study. Final performance report

    SciTech Connect (OSTI)

    Samet, J.; Gilliland, F.D.

    1998-08-13T23:59:59.000Z

    This project incorporates two related research projects directed toward understanding respiratory carcinogenesis in radon-exposed former uranium miners. The first project involved a continuation of the tissue resource of lung cancer cases from former underground uranium miners and comparison cases from non-miners. The second project was a pilot study for a proposed longitudinal study of respiratory carcinogenesis in former uranium miners. The objectives including facilitating the investigation of molecular changes in radon exposed lung cancer cases, developing methods for prospectively studying clinical, cytologic, cytogenetic, and molecular changes in the multi-event process of respiratory carcinogenesis, and assessing the feasibility of recruiting former uranium miners into a longitudinal study that collected multiple biological specimens. A pilot study was conducted to determine whether blood collection, induced sputum, bronchial brushing, washings, and mucosal biopsies from participants at two of the hospitals could be included efficiently. A questionnaire was developed for the extended study and all protocols for specimen collection and tissue handling were completed. Resource utilization is in progress at ITRI and the methods have been developed to study molecular and cellular changes in exfoliated cells contained in sputum as well as susceptibility factors.

  13. Physical and mechanical metallurgy of uranium and uranium alloys

    SciTech Connect (OSTI)

    Eckelmeyer, K.H. [Sandia National Labs. (United States)

    1998-12-31T23:59:59.000Z

    Engineering disadvantages of unalloyed uranium include relatively low strength, low ductility, and poor oxidation and corrosion resistance. As-cast uranium typically exhibits very large grains that cause nonuniform deformation and low tensile ductility. Uranium is often alloyed to improve its corrosion resistance and mechanical properties. Titanium is most commonly used to increase strength; niobium and molybdenum, to increase oxidation and corrosion resistance; and vanadium, to refine alpha grain size in castings. Under equilibrium conditions these elements are extensively soluble in the high-temperature gamma phase, slightly soluble in the intermediate temperature beta phase, and essentially insoluble in the low-temperature alpha phase. Uranium alloys are vacuum solution heat treated in the gamma range to dissolve the alloying elements and remove hydrogen. The subsequent microstructures and properties are determined by the cooling rate from the solution treatment temperature. Oxidation and corrosion resistance increases with increasing the amount of alloy in solid solution. As a result, alloys such as U-6%Nb and U-10%Mo are often used in applications requiring good corrosion resistance.

  14. Remediation of chromium(VI) in the vadose zone: stoichiometry and kinetics of chromium(VI) reduction by sulfur dioxide

    E-Print Network [OSTI]

    Ahn, Min

    2004-11-15T23:59:59.000Z

    and kinetics of chromium reduction both in aqueous solutions at pH values near neutrality and in soil. First, batch experiments and elemental analyses were conducted to characterize the stoichiometry and kinetics of Cr(VI) reduction in water...

  15. Removal of uranium from aqueous HF solutions

    DOE Patents [OSTI]

    Pulley, Howard (West Paducah, KY); Seltzer, Steven F. (Paducah, KY)

    1980-01-01T23:59:59.000Z

    This invention is a simple and effective method for removing uranium from aqueous HF solutions containing trace quantities of the same. The method comprises contacting the solution with particulate calcium fluoride to form uranium-bearing particulates, permitting the particulates to settle, and separting the solution from the settled particulates. The CaF.sub.2 is selected to have a nitrogen surface area in a selected range and is employed in an amount providing a calcium fluoride/uranium weight ratio in a selected range. As applied to dilute HF solutions containing 120 ppm uranium, the method removes at least 92% of the uranium, without introducing contaminants to the product solution.

  16. Process for alloying uranium and niobium

    DOE Patents [OSTI]

    Holcombe, Cressie E. (Farragut, TN); Northcutt, Jr., Walter G. (Oak Ridge, TN); Masters, David R. (Knoxville, TN); Chapman, Lloyd R. (Knoxville, TN)

    1991-01-01T23:59:59.000Z

    Alloys such as U-6Nb are prepared by forming a stacked sandwich array of uraniun sheets and niobium powder disposed in layers between the sheets, heating the array in a vacuum induction melting furnace to a temperature such as to melt the uranium, holding the resulting mixture at a temperature above the melting point of uranium until the niobium dissolves in the uranium, and casting the uranium-niobium solution. Compositional uniformity in the alloy product is enabled by use of the sandwich structure of uranium sheets and niobium powder.

  17. Bacterial Community Succession During in situ Uranium Bioremediation: Spatial Similarities Along Controlled Flow Paths

    SciTech Connect (OSTI)

    Hwang, Chiachi; Wu, Weimin; Gentry, Terry J.; Carley, Jack; Corbin, Gail A.; Carroll, Sue L.; Watson, David B.; Jardine, Phil M.; Zhou, Jizhong; Criddle, Craig S.; Fields, Matthew W.

    2009-05-22T23:59:59.000Z

    Bacterial community succession was investigated in a field-scale subsurface reactor formed by a series of wells that received weekly ethanol additions to re-circulating groundwater. Ethanol additions stimulated denitrification, metal reduction, sulfate reduction, and U(VI) reduction to sparingly soluble U(IV). Clone libraries of SSU rRNA gene sequences from groundwater samples enabled tracking of spatial and temporal changes over a 1.5 y period. Analyses showed that the communities changed in a manner consistent with geochemical variations that occurred along temporal and spatial scales. Canonical correspondence analysis revealed that the levels of nitrate, uranium, sulfide, sulfate, and ethanol strongly correlated with particular bacterial populations. As sulfate and U(VI) levels declined, sequences representative of sulfate-reducers and metal-reducers were detected at high levels. Ultimately, sequences associated with sulfate-reducing populations predominated, and sulfate levels declined as U(VI) remained at low levels. When engineering controls were compared to the population variation via canonical ordination, changes could be related to dissolved oxygen control and ethanol addition. The data also indicated that the indigenous populations responded differently to stimulation for bio-reduction; however, the two bio-stimulated communities became more similar after different transitions in an idiosyncratic manner. The strong associations between particular environmental variables and certain populations provide insight into the establishment of practical and successful remediation strategies in radionuclide-contaminated environments with respect to engineering controls and microbial ecology.

  18. Secondary Uranium-Phase Paragenesis and Incorporation of Radionuclides into Secondary Phase

    SciTech Connect (OSTI)

    R. Finch

    2001-06-05T23:59:59.000Z

    The purpose of this analysis/model report (AMR) is to assess the potential for uranium (U) (VI) compounds, formed during the oxidative corrosion of spent uranium-oxide (UO{sub 2}) fuels, to sequester certain radionuclides and, thereby, limit their release. The ''unsaturated drip tests'' being conducted at Argonne National Laboratory (ANL) provide the basis of this AMR (Table 1). The ANL drip tests on spent fuel are the only experiments on fuel corrosion from which solids have been analyzed for trace levels of radionuclides. Brief summaries are provided of the results from other selected corrosion and dissolution experiments on spent UO{sub 2} fuels, specifically those conducted under nominally oxidizing conditions. Discussions of the current understanding of thermodynamic and kinetic properties of U(VI) compounds is provided in order to outline the scientific basis for modeling precipitation and dissolution of potential radionuclide-bearing phases under repository-relevant conditions. Attachment I provides additional information on corrosion mechanisms and behaviors of radionuclides in the tests at ANL. Attachment II reviews occurrence, formation, and alteration (collectively known as paragenesis) of naturally occurring U(VI) minerals because natural mineral occurrences can be used to assess the possible long-term behaviors of U(VI) compounds formed in short-term laboratory experiments and to extrapolate experimental results to repository-relevant time scales. This AMR develops a model for calculating dissolved concentrations of radionuclides that are incorporated into U(VI) compounds, which is an alternative to models currently used in TSPA to calculate dissolved concentration limits for certain radionuclides. In particular, the model developed in this AMR applies to Np (neptunium) concentrations being controlled by solid uranyl oxyhydroxides that are known to contain trace levels of Np. The results of this AMR and the conceptual model developed from it and presented in Section 6.7.2.3 are primarily intended to support sensitivity evaluations in performance assessment. This AMR was developed in accordance with the ''Technical Work Plan for Waste Form Degradation Process Model Report for SR'' (CRWMS M&O 2000a). The scope of this AMR is outlined in the section ''Mixed Phase Dissolved Radionuclide Concentration Limits'' of the technical work plan.

  19. Uranium 2014 resources, production and demand

    E-Print Network [OSTI]

    Organisation for Economic Cooperation and Development. Paris

    2014-01-01T23:59:59.000Z

    Published every other year, Uranium Resources, Production, and Demand, or the "Red Book" as it is commonly known, is jointly prepared by the OECD Nuclear Energy Agency and the International Atomic Energy Agency. It is the recognised world reference on uranium and is based on official information received from 43 countries. It presents the results of a thorough review of world uranium supplies and demand and provides a statistical profile of the world uranium industry in the areas of exploration, resource estimates, production and reactor-related requirements. It provides substantial new information from all major uranium production centres in Africa, Australia, Central Asia, Eastern Europe and North America. Long-term projections of nuclear generating capacity and reactor-related uranium requirements are provided as well as a discussion of long-term uranium supply and demand issues. This edition focuses on recent price and production increases that could signal major changes in the industry.

  20. Uranium 2011 resources, production and demand

    E-Print Network [OSTI]

    Organisation for Economic Cooperation and Development. Paris

    2012-01-01T23:59:59.000Z

    In the wake of the Fukushima Daiichi nuclear power plant accident, questions are being raised about the future of the uranium market, including as regards the number of reactors expected to be built in the coming years, the amount of uranium required to meet forward demand, the adequacy of identified uranium resources to meet that demand and the ability of the sector to meet reactor requirements in a challenging investment climate. This 24th edition of the “Red Book”, a recognised world reference on uranium jointly prepared by the OECD Nuclear Energy Agency and the International Atomic Energy Agency, provides analyses and information from 42 producing and consuming countries in order to address these and other questions. It offers a comprehensive review of world uranium supply and demand as well as data on global uranium exploration, resources, production and reactor-related requirements. It also provides substantive new information on established uranium production centres around the world and in countri...

  1. Uranium 2005 resources, production and demand

    E-Print Network [OSTI]

    Organisation for Economic Cooperation and Development. Paris

    2006-01-01T23:59:59.000Z

    Published every other year, Uranium Resources, Production, and Demand, or the "Red Book" as it is commonly known, is jointly prepared by the OECD Nuclear Energy Agency and the International Atomic Energy Agency. It is the recognised world reference on uranium and is based on official information received from 43 countries. This 21st edition presents the results of a thorough review of world uranium supplies and demand as of 1st January 2005 and provides a statistical profile of the world uranium industry in the areas of exploration, resource estimates, production and reactor-related requirements. It provides substantial new information from all major uranium production centres in Africa, Australia, Central Asia, Eastern Europe and North America. Projections of nuclear generating capacity and reactor-related uranium requirements through 2025 are provided as well as a discussion of long-term uranium supply and demand issues. This edition focuses on recent price and production increases that could signal major c...

  2. From Nanowires to Biofilms: An Exploration of Novel Mechanisms of Uranium Transformation Mediated by Geobacter Bacteria

    SciTech Connect (OSTI)

    REGUERA, GEMMA [Michigan State University

    2014-01-16T23:59:59.000Z

    One promising strategy for the in situ bioremediation of radioactive groundwater contaminants that has been identified by the SBR Program is to stimulate the activity of dissimilatory metal-reducing microorganisms to reductively precipitate uranium and other soluble toxic metals. The reduction of U(VI) and other soluble contaminants by Geobacteraceae is directly dependent on the reduction of Fe(III) oxides, their natural electron acceptor, a process that requires the expression of Geobacter’s conductive pili (pilus nanowires). Expression of conductive pili by Geobacter cells leads to biofilm development on surfaces and to the formation of suspended biogranules, which may be physiological closer to biofilms than to planktonic cells. Biofilm development is often assumed in the subsurface, particularly at the matrix-well screen interface, but evidence of biofilms in the bulk aquifer matrix is scarce. Our preliminary results suggest, however, that biofilms develop in the subsurface and contribute to uranium transformations via sorption and reductive mechanisms. In this project we elucidated the mechanism(s) for uranium immobilization mediated by Geobacter biofilms and identified molecular markers to investigate if biofilm development is happening in the contaminated subsurface. The results provided novel insights needed in order to understand the metabolic potential and physiology of microorganisms with a known role in contaminant transformation in situ, thus having a significant positive impact in the SBR Program and providing novel concept to monitor, model, and predict biological behavior during in situ treatments.

  3. Interstellar O VI in the Large Magellanic Cloud

    E-Print Network [OSTI]

    J. Christopher Howk

    2001-09-14T23:59:59.000Z

    I summarize Far Ultraviolet Spectroscopic Explorer (FUSE) observations of interstellar O VI absorption towards 12 early-type stars in the Large Magellanic Cloud (LMC), the closest disk galaxy to the Milky Way. LMC O VI is seen towards all 12 stars with properties (average column densities, kinematics) very similar to those of the Milky Way halo, even though O/H in the LMC is lower by a factor of ~2.5. Sight lines projected onto known LMC superbubbles show little enhancement in O VI column density compared to sight lines towards quiescent regions of the LMC. The O VI absorption is displaced by \\~-30 km/sec from the corresponding low-ionization absorption associated with the bulk of the LMC gas. The LMC O VI most likely arises in a vertically-extended distribution, and I discuss the measurements in the context of a halo composed of radiatively-cooling hot gas. In this case, the mass-flow rate from one side of the LMC disk is of the order 1 solar mass/yr.

  4. Reports on investigations of uranium anomalies. National Uranium Resource Evaluation

    SciTech Connect (OSTI)

    Goodknight, C.S.; Burger, J.A. (comps.) [comps.

    1982-10-01T23:59:59.000Z

    During the National Uranium Resource Evaluation (NURE) program, conducted for the US Department of Energy (DOE) by Bendix Field Engineering Corporation (BFEC), radiometric and geochemical surveys and geologic investigations detected anomalies indicative of possible uranium enrichment. Data from the Aerial Radiometric and Magnetic Survey (ARMS) and the Hydrogeochemical and Stream-Sediment Reconnaissance (HSSR), both of which were conducted on a national scale, yielded numerous anomalies that may signal areas favorable for the occurrence of uranium deposits. Results from geologic evaluations of individual 1/sup 0/ x 2/sup 0/ quadrangles for the NURE program also yielded anomalies, which could not be adequately checked during scheduled field work. Included in this volume are individual reports of field investigations for the following six areas which were shown on the basis of ARMS, HSSR, and (or) geologic data to be anomalous: (1) Hylas zone and northern Richmond basin, Virginia; (2) Sischu Creek area, Alaska; (3) Goodman-Dunbar area, Wisconsin; (4) McCaslin syncline, Wisconsin; (5) Mt. Withington Cauldron, Socorro County, New Mexico; (6) Lake Tecopa, Inyo County, California. Field checks were conducted in each case to verify an indicated anomalous condition and to determine the nature of materials causing the anomaly. The ultimate objective of work is to determine whether favorable conditions exist for the occurrence of uranium deposits in areas that either had not been previously evaluated or were evaluated before data from recent surveys were available. Most field checks were of short duration (2 to 5 days). The work was done by various investigators using different procedures, which accounts for variations in format in their reports. All papers have been abstracted and indexed.

  5. Significant Association between Sulfate-Reducing Bacteria and Uranium-Reducing Microbial Communities as Revealed by a Combined Massively Parallel Sequencing-Indicator Species Approach

    SciTech Connect (OSTI)

    Cardenas, Erick [Michigan State University, East Lansing; Leigh, Mary Beth [Michigan State University, East Lansing; Marsh, Terence [Michigan State University, East Lansing; Tiedje, James M. [Michigan State University, East Lansing; Wu, Wei-min [Stanford University; Luo, Jian [Stanford University; Ginder-Vogel, Matthew [Stanford University; Kitanidis, Peter K. [Stanford University; Criddle, Craig [Stanford University; Carley, Jack M [ORNL; Carroll, Sue L [ORNL; Gentry, Terry J [ORNL; Watson, David B [ORNL; Gu, Baohua [ORNL; Jardine, Philip M [ORNL; Zhou, Jizhong [ORNL

    2010-10-01T23:59:59.000Z

    Massively parallel sequencing has provided a more affordable and high-throughput method to study microbial communities, although it has mostly been used in an exploratory fashion. We combined pyrosequencing with a strict indicator species statistical analysis to test if bacteria specifically responded to ethanol injection that successfully promoted dissimilatory uranium(VI) reduction in the subsurface of a uranium contamination plume at the Oak Ridge Field Research Center in Tennessee. Remediation was achieved with a hydraulic flow control consisting of an inner loop, where ethanol was injected, and an outer loop for flow-field protection. This strategy reduced uranium concentrations in groundwater to levels below 0.126 M and created geochemical gradients in electron donors from the inner-loop injection well toward the outer loop and downgradient flow path. Our analysis with 15 sediment samples from the entire test area found significant indicator species that showed a high degree of adaptation to the three different hydrochemical-created conditions. Castellaniella and Rhodanobacter characterized areas with low pH, heavy metals, and low bioactivity, while sulfate-, Fe(III)-, and U(VI)-reducing bacteria (Desulfovibrio, Anaeromyxobacter, and Desulfosporosinus) were indicators of areas where U(VI) reduction occurred. The abundance of these bacteria, as well as the Fe(III) and U(VI) reducer Geobacter, correlated with the hydraulic connectivity to the substrate injection site, suggesting that the selected populations were a direct response to electron donor addition by the groundwater flow path. A false-discovery-rate approach was implemented to discard false-positive results by chance, given the large amount of data compared.

  6. A combined massively parallel sequencing indicator species approach revealed significant association between sulfate-reducing bacteria and uranium-reducing microbial communities

    SciTech Connect (OSTI)

    Cardenas, Erick [Michigan State University, East Lansing; Wu, Wei-min [Stanford University; Leigh, Mary Beth [Michigan State University, East Lansing; Carley, Jack M [ORNL; Carroll, Sue L [ORNL; Gentry, Terry [Texas A& M University; Luo, Jian [Georgia Institute of Technology; Watson, David B [ORNL; Gu, Baohua [ORNL; Ginder-Vogel, Matthew A. [Stanford University; Kitanidis, Peter K. [Stanford University; Jardine, Philip [University of Tennessee; Kelly, Shelly D [Argonne National Laboratory (ANL); Zhou, Jizhong [University of Oklahoma, Norman; Criddle, Craig [Stanford University; Marsh, Terence [Michigan State University, East Lansing; Tiedje, James [Michigan State University, East Lansing

    2010-08-01T23:59:59.000Z

    Massively parallel sequencing has provided a more affordable and high throughput method to study microbial communities, although it has been mostly used in an exploratory fashion. We combined pyrosequencing with a strict indicator species statistical analysis to test if bacteria specifically responded to ethanol injection that successfully promoted dissimilatory uranium (VI) reduction in the subsurface of a uranium contamination plume at the Oak Ridge Field Research Center in Tennessee, USA. Remediation was achieved with a hydraulic flow control consisting of an inner loop, where ethanol was injected, and an outer loop for flow field protection. This strategy reduced uranium concentrations in groundwater to levels below 0.126 {micro}M, and created geochemical gradients in electron donors from the inner loop injection well towards the outer loop and down-gradient flow path. Our analysis with 15 sediment samples from the entire test area found significant indicator species that showed a high degree of adaptation to the three different hydrochemical created conditions. Castellaniella, and Rhodanobacter characterized areas with low pH, heavy metals, and low bioactivity; while sulfate-, Fe(III)-, and U(VI)-reducing bacteria (Desulfovibrio, Anaeromyxobacter, and Desulfosporosinus) were indicators of areas where U(VI) reduction occurred. Abundance of these bacteria as well as the Fe(III)- and U(VI)-reducer Geobacter correlated with the hydraulic connectivity to the substrate injection site, suggesting that the selected populations were a direct response to the electron donor addition and by the groundwater flow path. A false discovery rate approach was implemented to discard false positives by chance given the large amount of data compared.

  7. Interphase Cytogenetics of Workers Exposed to Benzene

    E-Print Network [OSTI]

    California at Berkeley, University of

    Interphase Cytogenetics of Workers Exposed to Benzene Luoping Zhang,1 Nathaniel Rothman,2 Yunxia has been used to demonstrate that the benzene metabolites hydroquinone and 1,2,4-benzenetriol induce FISH procedure to perform cytogenetic analyses on the blood cells of 43 workers exposed to benzene

  8. Global terrestrial uranium supply and its policy implications : a probabilistic projection of future uranium costs

    E-Print Network [OSTI]

    Matthews, Isaac A

    2010-01-01T23:59:59.000Z

    An accurate outlook on long-term uranium resources is critical in forecasting uranium costresource relationships, and for energy policy planning as regards the development and deployment of nuclear fuel cycle alternatives. ...

  9. Overview of toxicity data and risk assessment methods for evaluating the chemical effects of depleted uranium compounds.

    SciTech Connect (OSTI)

    Hartmann, H. M.; Monette, F. A.; Avci, H. I.; Environmental Assessment

    2000-10-01T23:59:59.000Z

    In the United States, depleted uranium is handled or used in several chemical forms by both governmental agencies and private industry (primarily companies producing and machining depleted uranium metal for military applications). Human exposure can occur as a result of handling these compounds, routine low-level effluent releases to the environment from processing facilities, or materials being accidentally released from storage locations or during processing or transportation. Exposure to uranium can result in both chemical and radiological toxicity, but in most instances chemical toxicity is of greater concern. This article discusses the chemical toxic effects from human exposure to depleted uranium compounds that are likely to be handled during the long-term management and use of depleted uranium hexafluoride (UF{sub 6}) inventories in the United States. It also reviews representative publications in the toxicological literature to establish appropriate reference values for risk assessments. Methods are described for evaluating chemical toxicity caused by chronic low-level exposure and acute exposure. Example risk evaluations are provided for illustration. Preliminary results indicate that chemical effects of chronic exposure to uranium compounds under normal operating conditions would be negligibly small. Results also show that acute exposures under certain accident conditions could cause adverse chemical effects among the populations exposed.

  10. Bacterial Community Succession During in situ Uranium Bioremediation: Spatial Similarities Along Controlled Flow Paths

    E-Print Network [OSTI]

    Hwang, Chiachi

    2009-01-01T23:59:59.000Z

    problem, and the use of depleted uranium and other heavyenvironmental hazard. Depleted uranium is weakly radioactive

  11. Uranium 2009 resources, production and demand

    E-Print Network [OSTI]

    Organisation for Economic Cooperation and Development. Paris

    2010-01-01T23:59:59.000Z

    With several countries currently building nuclear power plants and planning the construction of more to meet long-term increases in electricity demand, uranium resources, production and demand remain topics of notable interest. In response to the projected growth in demand for uranium and declining inventories, the uranium industry – the first critical link in the fuel supply chain for nuclear reactors – is boosting production and developing plans for further increases in the near future. Strong market conditions will, however, be necessary to trigger the investments required to meet projected demand. The "Red Book", jointly prepared by the OECD Nuclear Energy Agency and the International Atomic Energy Agency, is a recognised world reference on uranium. It is based on information compiled in 40 countries, including those that are major producers and consumers of uranium. This 23rd edition provides a comprehensive review of world uranium supply and demand as of 1 January 2009, as well as data on global ur...

  12. Depleted uranium disposal options evaluation

    SciTech Connect (OSTI)

    Hertzler, T.J.; Nishimoto, D.D.; Otis, M.D. [Science Applications International Corp., Idaho Falls, ID (United States). Waste Management Technology Div.

    1994-05-01T23:59:59.000Z

    The Department of Energy (DOE), Office of Environmental Restoration and Waste Management, has chartered a study to evaluate alternative management strategies for depleted uranium (DU) currently stored throughout the DOE complex. Historically, DU has been maintained as a strategic resource because of uses for DU metal and potential uses for further enrichment or for uranium oxide as breeder reactor blanket fuel. This study has focused on evaluating the disposal options for DU if it were considered a waste. This report is in no way declaring these DU reserves a ``waste,`` but is intended to provide baseline data for comparison with other management options for use of DU. To PICS considered in this report include: Retrievable disposal; permanent disposal; health hazards; radiation toxicity and chemical toxicity.

  13. SUIVI MEDICAL DE SALARIES EXPOSES AU BERYLLIUM : Medical follow-up of beryllium -exposed workers

    E-Print Network [OSTI]

    Boyer, Edmond

    1 SUIVI MEDICAL DE SALARIES EXPOSES AU BERYLLIUM : Medical follow-up of beryllium - exposed workers-up of beryllium-exposed workers. Method: a medical follow-up of workers from a factory machining beryllium (Be preventive measures. Key words: beryllium, sensitisation, occupational exposure, prevention, Lymphocyte

  14. L'URANIUM ET LES ARMES L'URANIUM APPAUVRI. Pierre Roussel*

    E-Print Network [OSTI]

    Boyer, Edmond

    L'URANIUM ET LES ARMES � L'URANIUM APPAUVRI. Pierre Roussel* Institut de Physique Nucléaire, CNRS massivement dans la guerre du Golfe, des obus anti- chars ont été utilisés, avec des "charges d'uranium, avec une charge de 300 g d'uranium et tiré par des avions, l'autre de 120 mm de diamètre avec une

  15. Uranium in prehistoric Indian pottery 

    E-Print Network [OSTI]

    Filberth, Ernest William

    1976-01-01T23:59:59.000Z

    . 2 to 25 ppm (Katz 1951). From thermal equilibrium calculations on the earth's core, mantle, and crust, and through actual analysis of samples, uranium was found to be concentrated in the earth's crust. According to modern geological thought..., as the uniformly molten earth cooled, its matter became separated into one vapor phase and three concentric condensed phases: the siderosphere (the earth's core, probably primarily molten iron), the chalcosphere forming the intermediate shell (the mantle...

  16. Dry process fluorination of uranium dioxide using ammonium bifluoride

    E-Print Network [OSTI]

    Yeamans, Charles Burnett, 1978-

    2003-01-01T23:59:59.000Z

    An experimental study was conducted to determine the practicality of various unit operations for fluorination of uranium dioxide. The objective was to prepare ammonium uranium fluoride double salts from uranium dioxide and ...

  17. albarrana uranium ores: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and purified uranium ore into uranium hexafluoride (UF 6), or the reduction of depleted uranium tetrafluoride (UF 4) to UF 6. SFC contends that these unknown authors 7 A...

  18. Review of uranium bioassay techniques

    SciTech Connect (OSTI)

    Bogard, J.S.

    1996-04-01T23:59:59.000Z

    A variety of analytical techniques is available for evaluating uranium in excreta and tissues at levels appropriate for occupational exposure control and evaluation. A few (fluorometry, kinetic phosphorescence analysis, {alpha}-particle spectrometry, neutron irradiation techniques, and inductively-coupled plasma mass spectrometry) have also been demonstrated as capable of determining uranium in these materials at levels comparable to those which occur naturally. Sample preparation requirements and isotopic sensitivities vary widely among these techniques and should be considered carefully when choosing a method. This report discusses analytical techniques used for evaluating uranium in biological matrices (primarily urine) and limits of detection reported in the literature. No cost comparison is attempted, although references are cited which address cost. Techniques discussed include: {alpha}-particle spectrometry; liquid scintillation spectrometry, fluorometry, phosphorometry, neutron activation analysis, fission-track counting, UV-visible absorption spectrophotometry, resonance ionization mass spectrometry, and inductively-coupled plasma mass spectrometry. A summary table of reported limits of detection and of the more important experimental conditions associated with these reported limits is also provided.

  19. Uranium Tris-aryloxide Derivatives Supported by Triazacyclononane: Engendering a Reactive Uranium(III)

    E-Print Network [OSTI]

    Meyer, Karsten

    , we are currently investigating the coordina- tion chemistry of uranium metal centers with classicalUranium Tris-aryloxide Derivatives Supported by Triazacyclononane: Engendering a Reactive Uranium, and Karsten Meyer* Contribution from the Department of Chemistry and Biochemistry, UniVersity of California

  20. Energy and momentum of Bianchi Type VI_h Universes

    E-Print Network [OSTI]

    Tripathy, S K; Pandey, G K; Singh, A K; Kumar, T; Xulu, S S

    2015-01-01T23:59:59.000Z

    We obtain the energy and momentum of the Bianchi type VI_h universes using different prescriptions for the energy-momentum complexes in the framework of general relativity. The energy and momentum of the Bianchi VI_h universe are found to be zero for the parameter h = -1 of the metric. The vanishing of these results support the conjecture of Tryon that Universe must have a zero net value for all conserved quantities.This also supports the work of Nathan Rosen with the Robertson-Walker metric. Moreover, it raises an interesting question: "Why h=-1 case is so special?"

  1. Energy and momentum of Bianchi Type VI_h Universes

    E-Print Network [OSTI]

    S. K. Tripathy; B. Mishra; G. K. Pandey; A. K. Singh; T. Kumar; S. S. Xulu

    2015-01-19T23:59:59.000Z

    We obtain the energy and momentum of the Bianchi type VI_h universes using different prescriptions for the energy-momentum complexes in the framework of general relativity. The energy and momentum of the Bianchi VI_h universe are found to be zero for the parameter h = -1 of the metric. The vanishing of these results support the conjecture of Tryon that Universe must have a zero net value for all conserved quantities.This also supports the work of Nathan Rosen with the Robertson-Walker metric. Moreover, it raises an interesting question: "Why h=-1 case is so special?"

  2. Colorimetric detection of uranium in water

    DOE Patents [OSTI]

    DeVol, Timothy A. (Clemson, SC); Hixon, Amy E. (Piedmont, SC); DiPrete, David P. (Evans, GA)

    2012-03-13T23:59:59.000Z

    Disclosed are methods, materials and systems that can be used to determine qualitatively or quantitatively the level of uranium contamination in water samples. Beneficially, disclosed systems are relatively simple and cost-effective. For example, disclosed systems can be utilized by consumers having little or no training in chemical analysis techniques. Methods generally include a concentration step and a complexation step. Uranium concentration can be carried out according to an extraction chromatographic process and complexation can chemically bind uranium with a detectable substance such that the formed substance is visually detectable. Methods can detect uranium contamination down to levels even below the MCL as established by the EPA.

  3. Final Uranium Leasing Program Programmatic Environmental Impact...

    Office of Environmental Management (EM)

    Leasing Program, under which DOE administers tracts of land in western Colorado for exploration, development, and the extraction of uranium and vanadium ores. ULP PEIS...

  4. Statistical data of the uranium industry

    SciTech Connect (OSTI)

    none,

    1982-01-01T23:59:59.000Z

    Statistical Data of the Uranium Industry is a compendium of information relating to US uranium reserves and potential resources and to exploration, mining, milling, and other activities of the uranium industry through 1981. The statistics are based primarily on data provided voluntarily by the uranium exploration, mining, and milling companies. The compendium has been published annually since 1968 and reflects the basic programs of the Grand Junction Area Office (GJAO) of the US Department of Energy. The production, reserves, and drilling information is reported in a manner which avoids disclosure of proprietary information.

  5. Distribution of uranium-bearing phases in soils from Fernald

    SciTech Connect (OSTI)

    Buck, E.C.; Brown, N.R.; Dietz, N.L.

    1993-12-31T23:59:59.000Z

    Electron beam techniques have been used to characterize uranium-contaminated soils and the Fernald Site, Ohio. Uranium particulates have been deposited on the soil through chemical spills and from the operation of an incinerator plant on the site. The major uranium phases have been identified by electron microscopy as uraninite, autunite, and uranium phosphite [U(PO{sub 3}){sub 4}]. Some of the uranium has undergone weathering resulting in the redistribution of uranium within the soil.

  6. High strength and density tungsten-uranium alloys

    DOE Patents [OSTI]

    Sheinberg, Haskell (Los Alamos, NM)

    1993-01-01T23:59:59.000Z

    Alloys of tungsten and uranium and a method for making the alloys. The amount of tungsten present in the alloys is from about 55 vol % to about 85 vol %. A porous preform is made by sintering consolidated tungsten powder. The preform is impregnated with molten uranium such that (1) uranium fills the pores of the preform to form uranium in a tungsten matrix or (2) uranium dissolves portions of the preform to form a continuous uranium phase containing tungsten particles.

  7. Proteogenomic monitoring of Geobacter physiology during stimulated uranium bioremediation

    SciTech Connect (OSTI)

    Wilkins, Michael J.; VerBerkmoes, Nathan C.; Williams, Kenneth H.; Callister, Stephen J.; Mouser, Paula; Elifantz, H.; N'Guessan, A. Lucie; Thomas, Brian C.; Nicora, Carrie D.; Shah, Manesh B.; Abraham, Paul; Lipton, Mary S.; Lovely, Derek R.; Hettich, Robert L.; Long, Philip E.; Banfield, Jillian F.

    2009-10-01T23:59:59.000Z

    Implementation of uranium bioremediation requires methods to monitor the membership and activities of the subsurface microbial communities that are responsible for reduction of soluble U(VI) to insoluble U(IV). Here we report a proteomics-based approach to simultaneously document strain membership and microbial physiology of the dominant Geobacter community members during in situ acetate amendment of the U-contaminated Rifle, CO aquifer. Three planktonic Geobacter-dominated samples were obtained from two wells down-gradient of acetate addition. Over 2,500 proteins from each of these samples were identified by matching LC MS/MS spectra to peptides predicted from 7 isolate Geobacter genomes. Genome-specific peptides indicate early proliferation of multiple M21 and G. bemidjiensis–like strains and later possible emergence of M21 and G. bemidjiensis–like strains more closely related to G. lovleyi. Throughout biostimulation, the proteome is dominated by enzymes that convert acetate to acetyl-CoA and pyruvate for central metabolism while abundant peptides matching TCA cycle proteins and ATP synthase subunits were also detected, indicating the importance of energy generation during the period of rapid growth following the start of biostimulation. Evolving Geobacter strain composition may be linked to changes in protein abundance over the course of biostimulation and may reflect changes in metabolic functioning. Thus, metagenomics independent community proteogenomics can be used to diagnose the status of the subsurface consortia upon which remediation biotechnology relies.

  8. Proteogenomic monitoring of Geobacter physiology during stimulated uranium bioremediation

    SciTech Connect (OSTI)

    Wilkins, Mike [University of California, Berkeley; Verberkmoes, Nathan C [ORNL; Williams, Ken [Lawrence Berkeley National Laboratory (LBNL); Callister, Stephen J [Pacific Northwest National Laboratory (PNNL); Mouser, Paula J [University of Massachusetts, Amherst; Elifantz, Hila [University of Massachusetts, Amherst; N'Guessan, A. Lucie [University of Massachusetts, Amherst; Thomas, Brian [University of California, Berkeley; Nicora, Carrie D. [Pacific Northwest National Laboratory (PNNL); Shah, Manesh B [ORNL; Abraham, Paul E [ORNL; Lipton, Mary S [Pacific Northwest National Laboratory (PNNL); Lovley, Derek [University of Massachusetts, Amherst; Hettich, Robert {Bob} L [ORNL; Long, Phil [Pacific Northwest National Laboratory (PNNL); Banfield, Jillian F. [University of California, Berkeley

    2009-01-01T23:59:59.000Z

    Implementation of uranium bioremediation requires methods to monitor the membership and activities of the subsurface microbial communities that are responsible for reduction of soluble U(VI) to insoluble U(IV). Here we report a proteomics-based approach to simultaneously document strain membership and microbial physiology of the dominant Geobacter community members during in situ acetate amendment of the U-contaminated Rifle, CO aquifer. Three planktonic Geobacter-dominated samples were obtained from two wells down-gradient of acetate addition. Over 2,500 proteins from each of these samples were identified by matching LC MS/MS spectra to peptides predicted from 7 isolate Geobacter genomes. Genome-specific peptides indicate early proliferation of multiple M21 and G. bemidjiensis like strains and later possible emergence of M21 and G. bemidjiensis like strains more closely related to G. lovleyi. Throughout biostimulation, the proteome is dominated by enzymes that convert acetate to acetyl-CoA and pyruvate for central metabolism while abundant peptides matching TCA cycle proteins and ATP synthase subunits were also detected, indicating the importance of energy generation during the period of rapid growth following the start of biostimulation. Evolving Geobacter strain composition may be linked to changes in protein abundance over the course of biostimulation and may reflect changes in metabolic functioning. Thus, metagenomics independent community proteogenomics can be used to diagnose the status of the subsurface consortia upon which remediation biotechnology relies.

  9. Proteogenomic monitoring of Geobacter physiology during stimulated uranium bioremediation

    SciTech Connect (OSTI)

    Wilkins, M.J.; VerBerkmoes, N.C.; Williams, K.H.; Callister, S.J.; Mouser, P.J.; Elifantz, H.; N'Guessan, A.L.; Thomas, B.C.; Nicora, C.D.; Shah, M.B.; Lipton, M.S.; Lovley, D.R.; Hettich, R.L.; Long, P.E.; Banfield, J.F.; Abraham, P.

    2009-08-01T23:59:59.000Z

    Implementation of uranium bioremediation requires methods for monitoring the membership and activities of the subsurface microbial communities that are responsible for reduction of soluble U(VI) to insoluble U(IV). Here, we report a proteomics-based approach for simultaneously documenting the strain membership and microbial physiology of the dominant Geobacter community members during in situ acetate amendment of the U-contaminated Rifle, CO, aquifer. Three planktonic Geobacter-dominated samples were obtained from two wells down-gradient of acetate addition. Over 2,500 proteins from each of these samples were identified by matching liquid chromatography-tandem mass spectrometry spectra to peptides predicted from seven isolate Geobacter genomes. Genome-specific peptides indicate early proliferation of multiple M21 and Geobacter bemidjiensis-like strains and later possible emergence of M21 and G. bemidjiensis-like strains more closely related to Geobacter lovleyi. Throughout biostimulation, the proteome is dominated by enzymes that convert acetate to acetyl-coenzyme A and pyruvate for central metabolism, while abundant peptides matching tricarboxylic acid cycle proteins and ATP synthase subunits were also detected, indicating the importance of energy generation during the period of rapid growth following the start of biostimulation. Evolving Geobacter strain composition may be linked to changes in protein abundance over the course of biostimulation and may reflect changes in metabolic functioning. Thus, metagenomics-independent community proteogenomics can be used to diagnose the status of the subsurface consortia upon which remediation biotechnology relies.

  10. Realities and perceptions : HOPE VI poverty deconcentration and implications for broader neighborhood revitalization

    E-Print Network [OSTI]

    Vanderford, Carrie Ann

    2006-01-01T23:59:59.000Z

    HOPE VI was developed in 1992 as program to demolish and revitalize the nation's most severely distressed public housing. One element of the HOPE VI program is to move low-income households out of an environment of ...

  11. Investigation of U(VI) Adsorption in Quartz-Chlorite Mineral...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    U(VI) Adsorption in Quartz-Chlorite Mineral Mixtures. Investigation of U(VI) Adsorption in Quartz-Chlorite Mineral Mixtures. Abstract: A batch and cryogenic laser-induced...

  12. Incorporation of Np(V) and U(VI) in Carbonate and Sulfate Minerals...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Np(V) and U(VI) in Carbonate and Sulfate Minerals Crystallized from Aqueous Solution. Incorporation of Np(V) and U(VI) in Carbonate and Sulfate Minerals Crystallized from Aqueous...

  13. Reaction of U-VI with titanium-substituted magnetite: Influence...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    U-VI with titanium-substituted magnetite: Influence of Ti on U-IV speciation. Reaction of U-VI with titanium-substituted magnetite: Influence of Ti on U-IV speciation. Abstract:...

  14. Toxic Substances Control Act Uranium Enrichment Federal Facility...

    Office of Environmental Management (EM)

    Toxic Substances Control Act Uranium Enrichment Federal Facility Compliance Agreement Toxic Substances Control Act Uranium Enrichment Federal Facility Compliance Agreement Toxic...

  15. Legacy Management Work Progresses on Defense-Related Uranium...

    Office of Environmental Management (EM)

    LM visited 84 defense-related legacy uranium mine sites located within 11 uranium mining districts in 6 western states. At these sites, photographs and global positioning...

  16. Uncertainty analysis of multi-rate kinetics of uranium desorption...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Uncertainty analysis of multi-rate kinetics of uranium desorption from sediments. Uncertainty analysis of multi-rate kinetics of uranium desorption from sediments. Abstract: A...

  17. Highly Enriched Uranium Materials Facility, Major Design Changes...

    Energy Savers [EERE]

    Highly Enriched Uranium Materials Facility, Major Design Changes Late...Lessons Learned Report, NNSA, Dec 2010 Highly Enriched Uranium Materials Facility, Major Design Changes...

  18. DOE Seeks Contractor for Depleted Uranium Hexafluoride (DUF6...

    Energy Savers [EERE]

    Contractor for Depleted Uranium Hexafluoride (DUF6) Operations at Ohio and Kentucky Facilities DOE Seeks Contractor for Depleted Uranium Hexafluoride (DUF6) Operations at Ohio and...

  19. Geochemical Controls on Contaminant Uranium in Vadose Hanford...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Controls on Contaminant Uranium in Vadose Hanford Formation Sediments at the 200 Area and 300 Area, Hanford Site, Geochemical Controls on Contaminant Uranium in Vadose Hanford...

  20. Microbial Reduction of Uranium under Iron- and Sulfate-reducing...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Uranium under Iron- and Sulfate-reducing Conditions: Effect of Amended Goethite on Microbial Community Microbial Reduction of Uranium under Iron- and Sulfate-reducing Conditions:...

  1. Microscopic Reactive Diffusion of Uranium in the Contaminated...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Reactive Diffusion of Uranium in the Contaminated Sediments at Hanford, United States. Microscopic Reactive Diffusion of Uranium in the Contaminated Sediments at Hanford, United...

  2. Y-12 uranium storage facility?a dream come true?

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ranks and actually provides the first impedance for the just finished highly enriched uranium storage facility. Recently the Highly Enriched Uranium Material Facility was...

  3. Composition, stability, and measurement of reduced uranium phases...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Composition, stability, and measurement of reduced uranium phases for groundwater bioremediation at Old Rifle, CO. Composition, stability, and measurement of reduced uranium phases...

  4. Record of Decision for the Uranium Leasing Program Programmatic...

    Energy Savers [EERE]

    Record of Decision for the Uranium Leasing Program Programmatic Environmental Impact Statement Record of Decision for the Uranium Leasing Program Programmatic Environmental Impact...

  5. Sequestering Uranium from Seawater: Binding Strength and Modes...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Sequestering Uranium from Seawater: Binding Strength and Modes of Uranyl Complexes with Glutarimidedioxime Sequestering Uranium from Seawater: Binding Strength and Modes of Uranyl...

  6. alloyed uranium transformation: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    were characterized in this research. Metal uranium powder was produced from pieces of depleted uranium metal acquired from the Y-12 plant via hydriding... Helmreich, Grant...

  7. EIS-0360: Depleted Uranium Oxide Conversion Product at the Portsmouth...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    60: Depleted Uranium Oxide Conversion Product at the Portsmouth, Ohio Site EIS-0360: Depleted Uranium Oxide Conversion Product at the Portsmouth, Ohio Site Summary This...

  8. acute uranium intoxication: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    consists of replacing the water with 20 Garland Jr., Theodore 8 Review The Toxicity of Depleted Uranium CiteSeer Summary: Abstract: Depleted uranium (DU) is an emerging...

  9. alloyed uranium sicral: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    were characterized in this research. Metal uranium powder was produced from pieces of depleted uranium metal acquired from the Y-12 plant via hydriding... Helmreich, Grant...

  10. Depleted Uranium Hexafluoride (DUF6) Fully Operational at the...

    Office of Environmental Management (EM)

    Depleted Uranium Hexafluoride (DUF6) Fully Operational at the Portsmouth and Paducah Gaseous Diffusion Sites Depleted Uranium Hexafluoride (DUF6) Fully Operational at the...

  11. Biomarker monitoring of a population residing near uranium mining activities

    SciTech Connect (OSTI)

    Au, W.W.; Legator, M.S.; Whorton, E.B.; Wilkinson, G.S.; Gabehart, G.J.; Lane, R.G. [Univ. of Texas Medical Branch, Galveston, TX (United States)

    1995-05-01T23:59:59.000Z

    We investigated whether residents residing near uranium mining operations (target population), who are potentially exposed to toxicants from mining waste, have increased genotoxic effects compared with people residing elsewhere (reference population). Population surveys were conducted, and 24 target and 24 reference residents were selected. The selected subjects and controls were matched on age and gender and they were nonsmokers. Blood samples were collected for laboratory studies. The standard cytogenetic assay was used to determine chromosome aberration frequencies, and the challenge assay was used to investigate DNA repair responses. We found that individuals who resided near uranium mining operations had a higher mean frequency of cells with chromosome aberrations and higher deletion frequency but lower dicentric frequency than the reference group, although the difference was not statistically significant. After cells were challenged by exposure to {gamma}-rays, the target population had a significantly higher frequency of cells with chromosome aberrations and deletion frequency than the reference group. The latter observation is indicative of abnormal DNA repair response in the target population. 22 refs., 3 tabs.

  12. Dissolution of Uranium-Bearing Minerals and Mobilization of Uranium by Organic Ligands in a Biologically Reduced Sediment

    SciTech Connect (OSTI)

    Luo, Wensui [ORNL; Gu, Baohua [ORNL

    2011-01-01T23:59:59.000Z

    The stability and mobility of uranium (U) is a concern following its reductive precipitation or immobilization by techniques such as bioremediation at contaminated sites. In this study, the influences of complexing organic ligands such as citrate and ethylenediaminetetraacetate (EDTA) on the mobilization of U were investigated in both batch and column flow systems using a contaminated and bioreduced sediment. Results indicate that both reduced U(IV) and oxidized U(VI) in the sediment can be effectively mobilized with the addition of EDTA or citrate under anaerobic conditions. The dissolution and mobilization of U appear to be correlated to the dissolution of iron (Fe)- or aluminum (Al)-bearing minerals, with EDTA being more effective (with R2 0.89) than citrate (R2 <0.60) in dissolving these minerals. The column flow experiments confirm that U, Fe, and Al can be mobilized by these ligands under anoxic conditions, although the cumulative amounts of U removal constituted ~0.1% of total U present in this sediment following a limited period of leaching. This study concludes that the presence of complexing organic ligands may pose a long-term concern by slowly dissolving U-bearing minerals and mobilizing U even under a strict anaerobic environment.

  13. Probing the 5f electrons in a plutonyl(VI) cluster complex

    SciTech Connect (OSTI)

    May, Iain [Los Alamos National Laboratory

    2009-01-01T23:59:59.000Z

    The authors report the structural, spectroscopic and preliminary magnetic characterization of a tri-metallic plutonyl(VI) polyoxometalate complex.

  14. THE HYMENOPTEROUS POISON APPARATUS. VI. CAMPONOTU8 PENNSYLYANICUS

    E-Print Network [OSTI]

    Villemant, Claire

    THE HYMENOPTEROUS POISON APPARATUS. VI. CAMPONOTU8 PENNSYLYANICUS (HYMENOPTERA: FORMICIDAE:or illustrations are in millimeters. In preparation for chemical analysis, poison sacs were dissected rom workers compounds present in the poison gland secretion were re- solved by applying the .contents of fifty glands

  15. Introduc)on of lab ac)vi)es

    E-Print Network [OSTI]

    Chen, Po

    ·Overview of lab ac)vi)es #12;·En-Jui (En-Ray) Lee · h@p://www.gg.uwyo.edu/ggstudent/elee8 of Water · The characteris)cs of tsunamis & the early warning systems. #12 · Hydraulic gradient and its calcula)on · How to determina)on of groundwater flow

  16. AM(VI) PARTITIONING STUDIES: FY14 FINAL REPORT

    SciTech Connect (OSTI)

    Bruce J Mincher

    2014-10-01T23:59:59.000Z

    The use of higher oxidation states of americium in partitioning from the lanthanides is under continued investigation by the sigma team. This is based on the hypothesis that Am(VI) can be produced and remain stable in irradiated first cycle raffinate solution long enough to perform solvent extraction for separations. The stability of Am(VI) to autoreduction was measured using millimolar americium concentrations in a 1-cm cell with a Cary 6000 UV/Vis spectrophotometer for data acquisition. At millimolar americium concentrations, Am(VI) is stable enough against its own autoreduction for separations purposes. A second major accomplishment during FY14 was the hot test. Americium oxidation and extraction was performed using a centrifugal contactor-based test bed consisting of an extraction stage and two stripping stages. Sixty-three percent americium extraction was obtained in one extraction stage, in agreement with batch contacts. Promising electrochemical oxidation results have also been obtained, using terpyridine ligand derivatized electrodes for binding of Am(III). Approximately 50 % of the Am(III) was oxidized to Am(V) over the course of 1 hour. It is believed that this is the first demonstration of the electrolytic oxidation of americium in a non-complexing solution. Finally, an initial investigation of Am(VI) extraction using diethylhexylbutyramide (DEHBA) was performed.

  17. Diplomatic Metonymy and Antithesis in 3 Henry VI

    E-Print Network [OSTI]

    Craigwood, J.

    2014-06-19T23:59:59.000Z

    love that leads inevitably from corporeal ‘feeble shadow’ (al corpo una debil umbra) to the soul’s immaterial and divine ‘substance’ (sustanzia).44 In other words, Camilla sceptically suspects a world like that of the Henry VI plays, a world of obscured...

  18. air pollution vi: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    air pollution vi First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Environmental Pollution Air Pollution...

  19. The effect of temperature on the speciation of U(VI) in sulfate solutions

    SciTech Connect (OSTI)

    Rao, Linfeng; Tian, Guoxin

    2008-09-15T23:59:59.000Z

    Sulfate, one of the inorganic constituents that could be present in the nuclear waste repository, forms complexes with U(VI) and affects its migration in the environment. Results show that the complexation of U(VI) with sulfate is enhanced by the increase in temperature. The effect of temperature on the complexation and speciation of U(VI) in sulfate solutions is discussed.

  20. Uranium potential of southwestern New Mexico (southern Hidalgo County), including observations on crystallization history of lavas and ash tuffs and the release of uranium from them. Final report

    SciTech Connect (OSTI)

    Walton, A.W.; Salter, T.L.; Zetterlund, D.

    1980-08-01T23:59:59.000Z

    Geological environments present in southwestern New Mexico include thick sequences of sedimentary rock including limestone, conglomerates, sandstone, and shale: igneous intrusions with associated metal deposits; caldera centers, margins, and outflow facies; and basins with marginal faults and thick late Cenozoic sedimentary fillings. Predominant rock types are Paleozoic carbonates, Mesozoic terrigeneous rocks and carbonates, and Cenozoic volcanic rocks and basin-filling terrigeneous rocks. Consideration of information available in Preliminary Reconnaissance Reports and in Hydrogeochemical and Stream Reconnaissance Reports together with 347 new whole rock chemical analyses points to three areas of anomalous uranium abundance in Hidalgo County, New Mexico. The area has experienced three major periods of igneous activity in Phanerozoic time: one associated with the Laramide cycle of the Late Cretaceous and early Tertiary, mid-Tertiary cycle of silicic volcanism with abundant calderas, and a late Tertiary cycle of mafic volcanism. Silicic volcanic rocks are the most common exposed rock type in the area, and the most enriched in uranium (range, 0.4 to 19 ppM). The most likely source for any uranium ore-forming solutions lies with this cycle of volcanism. Solutions might have been introduced during volcanism or formed later by groundwater leaching of cooled volcanic rocks. Results indicate that groundwater leaching of cooled volcanic rocks was not an effective means of mobilizing uranium in the area. Study of several rhyolite lava flows indicates that they were emplaced in supercooled condition and may have crystallized completely at temperatures well below their liquids, or they may have warmed as crystallization released latent heat. Statistical comparison of the uranium concentration revealed no differences between vitrophyres and associated felsites.

  1. Control of structure and reactivity by ligand design : applications to small molecule activation by low-valent uranium complexes

    E-Print Network [OSTI]

    Lam, Oanh Phi

    2010-01-01T23:59:59.000Z

    Coordination Chemistry of Uranium………………………………….11 1.4researchers from uranium chemistry. Fortunately, despiteclassical coordination chemistry of uranium has flourished

  2. Uranium Management - Preservation of a National Asset

    SciTech Connect (OSTI)

    Jackson, J. D.; Stroud, J. C.

    2002-02-27T23:59:59.000Z

    The Uranium Management Group (UMG) was established at the Department of Energy's (DOE's) Oak Ridge Operations in 1999 as a mechanism to expedite the de-inventory of surplus uranium from the Fernald Environmental Management Project site. This successful initial venture has broadened into providing uranium material de-inventory and consolidation support to the Hanford site as well as retrieving uranium materials that the Department had previously provided to universities under the loan/lease program. As of December 31, 2001, {approx} 4,300 metric tons of uranium (MTU) have been consolidated into a more cost effective interim storage location at the Portsmouth site near Piketon, OH. The UMG continues to uphold its corporate support mission by promoting the Nuclear Materials Stewardship Initiative (NMSI) and the twenty-five (25) action items of the Integrated Nuclear Materials Management Plan (1). Before additional consolidation efforts may commence to remove excess inventory from Environmental Management closure sites and universities, a Programmatic Environmental Assessment (PEA) must be completed. Two (2) noteworthy efforts currently being pursued involve the investigation of re-use opportunities for surplus uranium materials and the recovery of usable uranium from the shutdown Portsmouth cascade. In summary, the UMG is available as a DOE complex-wide technical resource to promote the responsible management of surplus uranium.

  3. Bioremediation of uranium contaminated soils and wastes

    SciTech Connect (OSTI)

    Francis, A.J.

    1998-12-31T23:59:59.000Z

    Contamination of soils, water, and sediments by radionuclides and toxic metals from uranium mill tailings, nuclear fuel manufacturing and nuclear weapons production is a major concern. Studies of the mechanisms of biotransformation of uranium and toxic metals under various microbial process conditions has resulted in the development of two treatment processes: (1) stabilization of uranium and toxic metals with reduction in waste volume and (2) removal and recovery of uranium and toxic metals from wastes and contaminated soils. Stabilization of uranium and toxic metals in wastes is accomplished by exploiting the unique metabolic capabilities of the anaerobic bacterium, Clostridium sp. The radionuclides and toxic metals are solubilized by the bacteria directly by enzymatic reductive dissolution, or indirectly due to the production of organic acid metabolites. The radionuclides and toxic metals released into solution are immobilized by enzymatic reductive precipitation, biosorption and redistribution with stable mineral phases in the waste. Non-hazardous bulk components of the waste volume. In the second process uranium and toxic metals are removed from wastes or contaminated soils by extracting with the complexing agent citric acid. The citric-acid extract is subjected to biodegradation to recover the toxic metals, followed by photochemical degradation of the uranium citrate complex which is recalcitrant to biodegradation. The toxic metals and uranium are recovered in separate fractions for recycling or for disposal. The use of combined chemical and microbiological treatment process is more efficient than present methods and should result in considerable savings in clean-up and disposal costs.

  4. Structural Characterization of and Plutonium Sorption on Mesoporous and Nanoparticulate Ferrihydrite

    E-Print Network [OSTI]

    Brogan, Luna Kestrel Schwaiger

    2012-01-01T23:59:59.000Z

    and W. Jingsong. Removal of uranium(VI) from aqueousfor prediction of uranium(VI) removal from groundwater by

  5. DISSOLUTION OF METAL OXIDES AND SEPARATION OF URANIUM FROM LANTHANIDES AND ACTINIDES IN SUPERCRITICAL CARBON DIOXIDE

    SciTech Connect (OSTI)

    Donna L. Quach; Bruce J. Mincher; Chien M. Wai

    2013-10-01T23:59:59.000Z

    This paper investigates the feasibility of extracting and separating uranium from lanthanides and other actinides by using supercritical fluid carbon dioxide (sc-CO2) as a solvent modified with tri-n-butylphosphate (TBP) for the development of a counter current stripping technique, which would be a more efficient and environmentally benign technology for spent nuclear fuel reprocessing compared to traditional solvent extraction. Several actinides (U, Pu, and Np) and europium were extracted in sc-CO2 modified with TBP over a range of nitric acid concentrations and then the actinides were exposed to reducing and complexing agents to suppress their extractability. According to this study, uranium/europium and uranium/plutonium extraction and separation in sc-CO2 modified with TBP is successful at nitric acid concentrations of less than 6 M and at nitric acid concentrations of less than 3 M with acetohydroxamic acid or oxalic acid, respectively. A scheme for recycling uranium from spent nuclear fuel by using sc-CO2 and counter current stripping columns is presented.

  6. Dissolution of metal oxides and separation of uranium from lanthanides and actinides in supercritical carbon dioxide

    SciTech Connect (OSTI)

    Quach, D.L.; Wai, C.M. [Department of Chemistry, University of Idaho, Moscow, Idaho 83844 (United States); Mincher, B.J. [Idaho National Lab, Idaho Falls, Idaho (United States)

    2013-07-01T23:59:59.000Z

    This paper investigates the feasibility of extracting and separating uranium from lanthanides and other actinides by using supercritical fluid carbon dioxide (sc-CO{sub 2}) as a solvent modified with tri-n-butylphosphate (TBP) for the development of a counter current stripping technique, which would be a more efficient and environmentally benign technology for spent nuclear fuel reprocessing compared to traditional solvent extraction. Several actinides (U, Pu, and Np) and europium were extracted in sc-CO{sub 2} modified with TBP over a range of nitric acid concentrations and then the actinides were exposed to reducing and complexing agents to suppress their extractability. According to this study, uranium/europium and uranium/plutonium extraction and separation in sc-CO{sub 2} modified with TBP is successful at nitric acid concentrations of less than 6 M and at nitric acid concentrations of less than 3 M with acetohydroxamic acid or oxalic acid, respectively. A scheme for recycling uranium from spent nuclear fuel by using sc-CO{sub 2} and counter current stripping columns is presented. (authors)

  7. Molten-Salt Depleted-Uranium Reactor

    E-Print Network [OSTI]

    Dong, Bao-Guo; Gu, Ji-Yuan

    2015-01-01T23:59:59.000Z

    The supercritical, reactor core melting and nuclear fuel leaking accidents have troubled fission reactors for decades, and greatly limit their extensive applications. Now these troubles are still open. Here we first show a possible perfect reactor, Molten-Salt Depleted-Uranium Reactor which is no above accident trouble. We found this reactor could be realized in practical applications in terms of all of the scientific principle, principle of operation, technology, and engineering. Our results demonstrate how these reactors can possess and realize extraordinary excellent characteristics, no prompt critical, long-term safe and stable operation with negative feedback, closed uranium-plutonium cycle chain within the vessel, normal operation only with depleted-uranium, and depleted-uranium high burnup in reality, to realize with fission nuclear energy sufficiently satisfying humanity long-term energy resource needs, as well as thoroughly solve the challenges of nuclear criticality safety, uranium resource insuffic...

  8. Recovery of uranium by immobilized polyhydroxyanthraquinone

    SciTech Connect (OSTI)

    Sakaguchi, T.; Nakajima, A.

    1986-01-01T23:59:59.000Z

    Nine species of polyhydroxyanthraquinone and two of polyhydroxynaphthoquinone were screened to determine which have the greatest ability to accumulate uranium. 1,2-Dihydroxyanthraquinone and 3-amino-1,2-dihydroxyanthraquinone have extremely high accumulation abilities. To improve the adsorbing characteristics of these compounds, the authors tried to immobilize these compounds by coupling with diazotized aminopolystyrene. The immobilized 1,2-dihydroxyanthraquinone has the most favorable features for uranium recovery; high selective adsorption ability to uranium, rapid adsorption rate, and applicability in both column and batch systems. This adsorbent can recover uranium almost quantitatively from natural seawater. Almost all uranium adsorbed is desorbed with a solution of 1 N HCl. Thus, immobilized 1,2-dihydroxyanthraquinone can be used repeatedly in the adsorption-desorption process.

  9. Scrap uranium recycling via electron beam melting

    SciTech Connect (OSTI)

    McKoon, R.

    1993-11-01T23:59:59.000Z

    A program is underway at the Lawrence Livermore National Laboratory (LLNL) to recycle scrap uranium metal. Currently, much of the material from forging and machining processes is considered radioactive waste and is disposed of by oxidation and encapsulation at significant cost. In the recycling process, uranium and uranium alloys in various forms will be processed by electron beam melting and continuously cast into ingots meeting applicable specifications for virgin material. Existing vacuum processing facilities at LLNL are in compliance with all current federal and state environmental, safety and health regulations for the electron beam melting and vaporization of uranium metal. One of these facilities has been retrofitted with an auxiliary electron beam gun system, water-cooled hearth, crucible and ingot puller to create an electron beam melt furnace. In this furnace, basic process R&D on uranium recycling will be performed with the goal of eventual transfer of this technology to a production facility.

  10. Method for fabricating laminated uranium composites

    DOE Patents [OSTI]

    Chapman, L.R.

    1983-08-03T23:59:59.000Z

    The present invention is directed to a process for fabricating laminated composites of uranium or uranium alloys and at least one other metal or alloy. The laminated composites are fabricated by forming a casting of the molten uranium with the other metal or alloy which is selectively positioned in the casting and then hot-rolling the casting into a laminated plate in or around which the casting components are metallurgically bonded to one another to form the composite. The process of the present invention provides strong metallurgical bonds between the laminate components primarily since the bond disrupting surface oxides on the uranium or uranium alloy float to the surface of the casting to effectively remove the oxides from the bonding surfaces of the components.

  11. Thermodynamic data for uranium fluorides

    SciTech Connect (OSTI)

    Leitnaker, J.M.

    1983-03-01T23:59:59.000Z

    Self-consistent thermodynamic data have been tabulated for uranium fluorides between UF/sub 4/ and UF/sub 6/, including UF/sub 4/ (solid and gas), U/sub 4/F/sub 17/ (solid), U/sub 2/F/sub 9/ (solid), UF/sub 5/ (solid and gas), U/sub 2/F/sub 10/ (gas), and UF/sub 6/ (solid, liquid, and gas). Included are thermal function - the heat capacity, enthalpy, and free energy function, heats of formation, and vaporization behavior.

  12. 2014 Domestic Uranium Production Report

    Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 111 1,613 122 40Coal Stocks at Commercial andSeptember 25,9,1996 N Y MDomestic Uranium Production

  13. 2014 Domestic Uranium Production Report

    Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 111 1,613 122 40Coal Stocks at Commercial andSeptember 25,9,1996 N Y MDomestic Uranium

  14. 2014 Domestic Uranium Production Report

    Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 111 1,613 122 40Coal Stocks at Commercial andSeptember 25,9,1996 N Y MDomestic Uranium9 2014

  15. 2014 Domestic Uranium Production Report

    Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 111 1,613 122 40Coal Stocks at Commercial andSeptember 25,9,1996 N Y MDomestic Uranium9

  16. 2014 Domestic Uranium Production Report

    Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 111 1,613 122 40Coal Stocks at Commercial andSeptember 25,9,1996 N Y MDomestic Uranium911 2014

  17. 2014 Domestic Uranium Production Report

    Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 111 1,613 122 40Coal Stocks at Commercial andSeptember 25,9,1996 N Y MDomestic Uranium911

  18. 2014 Domestic Uranium Production Report

    Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 111 1,613 122 40Coal Stocks at Commercial andSeptember 25,9,1996 N Y MDomestic Uranium9117 2014

  19. 2014 Domestic Uranium Production Report

    Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 111 1,613 122 40Coal Stocks at Commercial andSeptember 25,9,1996 N Y MDomestic Uranium9117 20145

  20. 2014 Domestic Uranium Production Report

    Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 111 1,613 122 40Coal Stocks at Commercial andSeptember 25,9,1996 N Y MDomestic Uranium9117

  1. 2014 Domestic Uranium Production Report

    Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 111 1,613 122 40Coal Stocks at Commercial andSeptember 25,9,1996 N Y MDomesticDomestic Uranium

  2. 2014 Domestic Uranium Production Report

    U.S. Energy Information Administration (EIA) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov YouKizildere IRaghurajiConventionalMississippi" ,"Plant","Primary1. TotalRevenueTotal97.10. Uranium

  3. 2014 Domestic Uranium Production Report

    U.S. Energy Information Administration (EIA) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov YouKizildere IRaghurajiConventionalMississippi" ,"Plant","Primary1. TotalRevenueTotal97.10. Uranium9.

  4. 2014 Uranium Marketing Annual Report

    U.S. Energy Information Administration (EIA) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov YouKizildere IRaghuraji Agro IndustriesTownDells,1 U.S. Department of Energygasoline4Residential17. Purchases of6a. Uranium

  5. 2014 Uranium Marketing Annual Report

    U.S. Energy Information Administration (EIA) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov YouKizildere IRaghuraji Agro IndustriesTownDells,1 U.S. Department of Energygasoline4Residential17. Purchases4. Uranium

  6. 2014 Uranium Marketing Annual Survey

    U.S. Energy Information Administration (EIA) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov YouKizildere IRaghuraji Agro IndustriesTownDells,1 U.S. Department of Energygasoline4Residential17. Purchases4. Uranium57.

  7. Composition, stability, and measurement of reduced uranium phases for groundwater bioremediation at Old Rifle, CO

    SciTech Connect (OSTI)

    Campbell, Kate M.; Davis, J. A.; Bargar, John R.; Giammar, Daniel E.; Bernier-Latmani, Rizlan; Kukkadapu, Ravi K.; Williams, K. H.; Veramani, H.; Ulrich, Kai-Uwe; Stubbs, J. B.; Yabusaki, Steven B.; Figueroa, Linda A.; Lesher, Emily; Wilkins, Michael J.; Peacock, Aaron D.; Longg, P. E.

    2011-03-26T23:59:59.000Z

    Reductive biostimulation is currently being explored as a possible remediation strategy for uranium (U) contaminated groundwater, and is currently being investigated at a field site in Rifle, CO, USA. The long-term stability of the resulting U(IV) phases is a key component of the overall performance and depends upon a variety of factors, including rate and mechanism of reduction, mineral associations in the subsurface, and propensity for oxidation. To address these factors, several approaches were used to evaluate the redox sensitivity of U: measurement of the rate of oxidative dissolution of biogenic uraninite (UO2(s)) deployed in groundwater at Rifle, characterization of a zone of natural bioreduction exhibiting relevant reduced mineral phases, and laboratory studies of the oxidative capacity of Fe(III) and reductive capacity of Fe(II) with regard to U(IV) and U(VI), respectively.

  8. Removal of uranium from uranium-contaminated soils -- Phase 1: Bench-scale testing. Uranium in Soils Integrated Demonstration

    SciTech Connect (OSTI)

    Francis, C. W.

    1993-09-01T23:59:59.000Z

    To address the management of uranium-contaminated soils at Fernald and other DOE sites, the DOE Office of Technology Development formed the Uranium in Soils Integrated Demonstration (USID) program. The USID has five major tasks. These include the development and demonstration of technologies that are able to (1) characterize the uranium in soil, (2) decontaminate or remove uranium from the soil, (3) treat the soil and dispose of any waste, (4) establish performance assessments, and (5) meet necessary state and federal regulations. This report deals with soil decontamination or removal of uranium from contaminated soils. The report was compiled by the USID task group that addresses soil decontamination; includes data from projects under the management of four DOE facilities [Argonne National Laboratory (ANL), Los Alamos National Laboratory (LANL), Oak Ridge National Laboratory (ORNL), and the Savannah River Plant (SRP)]; and consists of four separate reports written by staff at these facilities. The fundamental goal of the soil decontamination task group has been the selective extraction/leaching or removal of uranium from soil faster, cheaper, and safer than current conventional technologies. The objective is to selectively remove uranium from soil without seriously degrading the soil`s physicochemical characteristics or generating waste forms that are difficult to manage and/or dispose of. Emphasis in research was placed more strongly on chemical extraction techniques than physical extraction techniques.

  9. Recovery of uranium by using new microorganisms isolated from North American uranium deposits

    SciTech Connect (OSTI)

    Sakaguchi, T.; Nakajima, A.; Tsuruta, T. [Miyazaki Medical College (Japan)

    1995-12-31T23:59:59.000Z

    Some attempts were made to remove uranium that may be present in refining effluents, mine tailings by using new microorganisms isolated from uranium deposits and peculiar natural environments. To screen microorganisms isolated from uranium deposits and peculiar natural environments in North America and Japan for maximal accumulation of uranium, hundreds of microorganisms were examined. Some microorganisms can accumulate about 500 mg (4.2 mEq) of uranium per gram of Microbial cells within 1 h. The uranium accumulation capacity of the cells exceeds that of commercially available chelating agents (2-3 mEq/g adsorbent). We attempted to recover uranium from uranium refining waste water by using new microorganisms. As a result, these microbial cells can recover trace amounts of uranium from uranium waste water with high efficiency. These strains also have a high accumulating ability for thorium. Thus, these new microorganisms can be used as an adsorbing agent for the removal of nuclear elements may be present in metallurgical effluents, mine tailings and other waste sources.

  10. A Geostatistical Study of the Uranium Deposit at Kvanefjeld,

    E-Print Network [OSTI]

    are identified by the discriminating effect of the individual variable. INIS descriptors; URANIUM ORES? RESERVES

  11. Uranium Cluster Chemistry DOI: 10.1002/anie.200906605

    E-Print Network [OSTI]

    Uranium Cluster Chemistry DOI: 10.1002/anie.200906605 Tetranuclear Uranium Clusters by Reductive in the coordination chemistry and small-molecule reactivity of uranium. Among the intriguing reactivity patterns of tetravalent uranium with 3,5-dimethylpyrazolate (Me2PzÀ ) led to forma- tion of an unprecedented homoleptic

  12. VI.4. SINGUL ARE KOHOMOLOGIE 313 VI.4.20. Beispiel. Aus Satz VI.4.11 und Beispiel V.4.13 bzw. Beispiel V.7.37

    E-Print Network [OSTI]

    Haller, Stefan

    , 12, . . . 0 sonst Ist n m dann induziert die kanonische Inklusion : HPn HPm Isomor- phismen : Hq (HPm ; G) = - Hq (HPn ; G), f¨ur alle q 2n. VI.4.22. Beispiel. Aus Satz VI.4.11 und Proposition V

  13. Influence of phosphate and silica on U(VI) precipitation from acidic and neutralized wastewaters

    SciTech Connect (OSTI)

    Kanematsu, Masakazu; Perdrial, Nicolas; Um, Wooyong; Chorover, Jon; O'Day, Peggy A.

    2014-04-22T23:59:59.000Z

    Uranium speciation and physical-chemical characteristics were studied in solids precipitated from synthetic acidic to circumneutral wastewaters in the presence and absence of dissolved silica and phosphate to examine thermodynamic and kinetic controls on phase formation. Composition of synthetic wastewater was based on disposal sites 216-U-8 and 216-U-12 Cribs at the Hanford site (WA, USA). In the absence of dissolved silica or phosphate, crystalline or amorphous uranyl oxide hydrates, either compreignacite or meta-schoepite, precipitated at pH 5 or 7 after 30 d of reaction, in agreement with thermodynamic calculations. In the presence of 1 mM dissolved silica representative of groundwater concentrations, amorphous phases dominated by compreignacite precipitated rapidly at pH 5 or 7 as a metastable phase and formation of poorly-crystalline boltwoodite, the thermodynamically stable uranyl silicate phase, was slow. In the presence of phosphate (3 mM), meta-ankoleite initially precipitated as the primary phase at pH 3, 5, or 7 regardless of the presence of 1 mM dissolved silica. Analysis of precipitates by U LIII-edge EXAFS indicated that “autunite-type” sheets of meta-ankoleite transformed to “phosphuranylite-type” sheets after 30 d of reaction, probably due to Ca substitution in the structure. Low solubility of uranyl phosphate phases limits dissolved U(VI) concentrations but differences in particle size, crystallinity, and precipitate composition vary with pH and base cation concentration, which will influence the thermodynamic and kinetic stability of these phases.

  14. Geochemical, mineralogical and microbiological characteristics of sediment from a naturally reduced zone in a uranium-contaminated aquifer

    SciTech Connect (OSTI)

    Campbell, Kate M.; Kukkadapu, Ravi K.; Qafoku, Nikolla; Peacock, Aaron D.; Lesher, E.; Williams, Kenneth H.; Bargar, John R.; Wilkins, Michael J.; Figueroa, Linda A.; Ranville, James; Davis, James; Long, Philip E.

    2012-05-23T23:59:59.000Z

    Localized zones or lenses of naturally reduced sediments have the potential to play a significant role in the fate and transport of redox-sensitive metals and metalloids in aquifers. To assess the mineralogy, microbiology, and redox processes that occur in these zones, we examined several cores from a region of naturally occurring reducing conditions in a uranium-contaminated aquifer (Rifle, CO). Sediment samples from a transect of cores ranging from oxic/suboxic Rifle aquifer sediment to naturally reduced sediment were analyzed for uranium and iron content, oxidation state, and mineralogy, reduced sulfur phases, and solid phase organic carbon content using a suite of analytical and spectroscopic techniques on bulk sediment and size fractions. Solid-phase uranium concentrations were higher in the naturally reduced zone, with a high proportion of the uranium present as reduced U(IV). The sediments were also elevated in reduced sulfur phases and Fe(II), indicating it is very likely that U(VI), Fe(III), and sulfate reduction occurred or is occurring in the sediment. The microbial community was assessed using lipid- and DNA-based techniques, and statistical redundancy analysis was performed to determine correlations between the microbial community and the geochemistry. Increased concentration of solid phase organic carbon and biomass in the naturally reduced sediment suggests that natural bioreduction is stimulated by a zone of increased organic carbon concentration associated with fine-grained material and lower permeability to groundwater flow. Characterization of the naturally bioreduced sediment provides an understanding of the natural processes that occur in the sediment under reducing conditions and how they may impact natural attenuation of radionuclides and other redox sensitive materials. Results also suggest the importance of recalcitrant organic carbon for maintaining reducing conditions and uranium immobilization.

  15. Rapid electron exchange between surface-exposed bacterial cytochromes...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    electron exchange between surface-exposed bacterial cytochromes and Fe(III) minerals. Rapid electron exchange between surface-exposed bacterial cytochromes and Fe(III) minerals....

  16. Pore-Scale Characterization of Biogeochemical Controls on Iron and Uranium Speciation under Flow Conditions

    SciTech Connect (OSTI)

    Pearce, Carolyn I.; Wilkins, Michael J.; Zhang, Changyong; Heald, Steve M.; Fredrickson, Jim K.; Zachara, John M.

    2012-09-17T23:59:59.000Z

    Etched silicon microfluidic pore network models (micromodels) with controlled chemical and redox gradients, mineralogy, and microbiology under continuous flow conditions are used for the incremental development of complex microenvironments that simulate subsurface conditions. We demonstrate the colonization of micromodel pore spaces by an anaerobic Fe(III)-reducing bacterial species (Geobacter sulfurreducens) and the enzymatic reduction of a bioavailable Fe(III) phase within this environment. Using both X-ray Microprobe and X-ray Absorption Spectroscopy, we investigate the combined effects of the precipitated Fe(III) phases and the microbial population on uranium biogeochemistry under flow conditions. Precipitated Fe(III) phases within the micromodel were most effectively reduced in the presence of an electron shuttle (AQDS), and Fe(II) ions adsorbed onto the precipitated mineral surface without inducing any structural change. In the absence of Fe(III), U(VI) was effectively reduced by the microbial population to insoluble U(IV), which was precipitated in discrete regions associated with biomass. In the presence of Fe(III) phases, however, both U(IV) and U(VI) could be detected associated with biomass, suggesting re-oxidation of U(IV) by localized Fe(III) phases. These results demonstrate the importance of the spatial localization of biomass and redox active metals, and illustrate the key effects of pore-scale processes on contaminant fate and reactive transport.

  17. Influence of ammonium availability on expression of nifD and amtB genes during biostimulation of a U(VI) contaminated aquifer: implications for U(VI) removal and monitoring the metabolic state of Geobacteraceae

    SciTech Connect (OSTI)

    Mouser, Paula J.; N'Guessan, A. Lucie; Elifantz, Hila; Holmes, Dawn E.; Williams, Kenneth H; Wilkins, Michael J.; Long, Philip E.; Lovley, Derek R.

    2009-03-25T23:59:59.000Z

    The influence of ammonium availability on bacterial community structure and the physiological status of Geobacter species during in situ bioremediation of uranium-contaminated groundwater was evaluated. Ammonium concentrations varied by 2 orders of magnitude (<4 to 400 ?M) across the study site. Analysis of 16S rRNA sequences suggested that ammonium may have been one factor influencing the community composition prior to acetate amendment with Rhodoferax species predominating over Geobacter species with higher ammonium and Dechloromonas species dominating at the site with lowest ammonium. However, once acetate was added and dissimilatory metal reduction was stimulated, Geobacter species became the predominant organisms at all locations. Rates of U(VI) reduction appeared to be more related to acetate concentrations rather than ammonium levels. In situ mRNA transcript abundance of the nitrogen fixation gene, nifD, and the ammonium transporter gene, amtB, in Geobacter species indicated that ammonium was the primary source of nitrogen during uranium reduction. The abundance of amtB was inversely correlated to ammonium levels, whereas nifD transcript levels were similar across all sites examined. These results suggest that nifD and amtB expression are closely regulated in response to ammonium availability to ensure an adequate supply of nitrogen while conserving cell resources. Thus, quantifying nifD and amtB transcript expression appears to be a useful approach for monitoring the nitrogen-related physiological status of subsurface Geobacter species. This study also emphasizes the need for more detailed analysis of geochemical and physiological interactions at the field scale in order to adequately model subsurface microbial processes during bioremediation.

  18. Thermodynamics of the Complexation of Uranium(VI) by oxalate in aqueous solution at 10-70oC

    E-Print Network [OSTI]

    Di Bernardo, Plinio

    2009-01-01T23:59:59.000Z

    cell was introduced in the measuring compartment of a Varian Cary-5G spectrophotometer equipped with a Peltier

  19. Rate-limited U(VI) desorption during a small-scale tracer test in a hetereogeneous uranium contaminated aquifer

    E-Print Network [OSTI]

    Fox, P.M.

    2013-01-01T23:59:59.000Z

    Work Plan for the UMTRA project Old Rifle site, GrandMill Tailings Remedial Action (UMTRA) sites and the Savannahof the contamination at the UMTRA sites lies within shallow

  20. Electrochemistry, Spectroscopy, and Reactivity of Uranium Complexes Supported by Ferrocene Diamide Ligands

    E-Print Network [OSTI]

    Duhovic, Selma

    2012-01-01T23:59:59.000Z

    J. L. , Pentavalent Uranium Chemistry-Synthetic Pursuit of afor Trivalent Uranium Chemistry. Inorg. Chem. 1989, 28, (and High-Valent Uranium Chemistry. Organometallics 2011,

  1. Recent International R&D Activities in the Extraction of Uranium from Seawater

    E-Print Network [OSTI]

    Rao, Linfeng

    2011-01-01T23:59:59.000Z

    Uranium and Rare Earth Elements Using Biomass of Algae, Bioinorganic ChemistryRecovery of uranium from sea water. Chemistry & Industry (uranium recovery from seawater. Industrial & Engineering Chemistry

  2. Decolonizing cartographies : sovereignty, territoriality, and maps of meaning in the uranium landscape

    E-Print Network [OSTI]

    Voyles, Traci Brynne

    2010-01-01T23:59:59.000Z

    continued mining and uranium exploration on and near theand thereby open to uranium exploration, claims-staking, andbe used for uranium mining or exploration. One Hispano

  3. Recent International R&D Activities in the Extraction of Uranium from Seawater

    E-Print Network [OSTI]

    Rao, Linfeng

    2011-01-01T23:59:59.000Z

    for extracting uranium from seawater. Brit. (1978), 3 pp.Ger. ). Recovery of uranium from seawater. Ger. Offen. (Ger. ). Recovery of uranium from seawater. Ger. Offen. (

  4. Sequestering Uranium from Seawater: Binding Strength and Modes of Uranyl Complexes with Glutarimidedioxime

    E-Print Network [OSTI]

    Tian, Guoxin

    2013-01-01T23:59:59.000Z

    Sequestering uranium from seawater: binding strength andin sequestering uranium from seawater, forms strongExtraction of uranium from seawater is very challenging, not

  5. Electrodic voltages accompanying stimulated bioremediation of a uranium-contaminated aquifer

    E-Print Network [OSTI]

    Williams, K.H.

    2010-01-01T23:59:59.000Z

    2008), Sustained Removal of Uranium From ContaminatedR. T. Anderson (2007), Uranium removal from groundwater viasulfide and the removal of uranium from groundwater. The

  6. Sulfur isotopes as indicators of amended bacterial sulfate reduction processes influencing field scale uranium bioremediation

    E-Print Network [OSTI]

    Druhan, J.L.

    2009-01-01T23:59:59.000Z

    sulfate reduction and uranium removal. The samples for thisanism of Sulfate and Uranium Removal. In M-23, low acetatethe highest rates of uranium removal were observed at redox

  7. Field-based detection and monitoring of uranium in contaminated groundwater using two immunosensors

    E-Print Network [OSTI]

    Melton, S.J.

    2010-01-01T23:59:59.000Z

    an in situ uranium bioremediation field site. Appl. Environ.undergoing uranium bioremediation. Int. J. Systematicstimulated uranium bioremediation. Appl. Environ. Microbiol.

  8. Electrochemistry, Spectroscopy, and Reactivity of Uranium Complexes Supported by Ferrocene Diamide Ligands

    E-Print Network [OSTI]

    Duhovic, Selma

    2012-01-01T23:59:59.000Z

    J. L. , Pentavalent Uranium Chemistry-Synthetic Pursuit of aand High-Valent Uranium Chemistry. Organometallics 2011,for Trivalent Uranium Chemistry. Inorg. Chem. 1989, 28, (

  9. Bacterial Community Succession During in situ Uranium Bioremediation: Spatial Similarities Along Controlled Flow Paths

    E-Print Network [OSTI]

    Hwang, Chiachi

    2009-01-01T23:59:59.000Z

    problem, and the use of depleted uranium and other heavyenvironmental hazard. Depleted uranium is weakly radioactiveMB. (2004). Depleted and natural uranium: chemistry and

  10. Responses of microbial community functional structures to pilot-scale uranium in situ bioremediation

    SciTech Connect (OSTI)

    Xu, M.; Wu, W.-M.; Wu, L.; He, Z.; Van Nostrand, J.D.; Deng, Y.; Luo, J.; Carley, J.; Ginder-Vogel, M.; Gentry, T.J.; Gu, B.; Watson, D.; Jardine, P.M.; Marsh, T.L.; Tiedje, J.M.; Hazen, T.C.; Criddle, C.S.; Zhou, J.

    2010-02-15T23:59:59.000Z

    A pilot-scale field test system with an inner loop nested within an outer loop was constructed for in situ U(VI) bioremediation at a US Department of Energy site, Oak Ridge, TN. The outer loop was used for hydrological protection of the inner loop where ethanol was injected for biostimulation of microorganisms for U(VI) reduction/immobilization. After 2 years of biostimulation with ethanol, U(VI) levels were reduced to below drinking water standard (<30 {micro}gl{sup -1}) in the inner loop monitoring wells. To elucidate the microbial community structure and functions under in situ uranium bioremediation conditions, we used a comprehensive functional gene array (GeoChip) to examine the microbial functional gene composition of the sediment samples collected from both inner and outer loop wells. Our study results showed that distinct microbial communities were established in the inner loop wells. Also, higher microbial functional gene number, diversity and abundance were observed in the inner loop wells than the outer loop wells. In addition, metal-reducing bacteria, such as Desulfovibrio, Geobacter, Anaeromyxobacter and Shewanella, and other bacteria, for example, Rhodopseudomonas and Pseudomonas, are highly abundant in the inner loop wells. Finally, the richness and abundance of microbial functional genes were highly correlated with the mean travel time of groundwater from the inner loop injection well, pH and sulfate concentration in groundwater. These results suggest that the indigenous microbial communities can be successfully stimulated for U bioremediation in the groundwater ecosystem, and their structure and performance can be manipulated or optimized by adjusting geochemical and hydrological conditions.

  11. Capstone Depleted Uranium Aerosols: Generation and Characterization

    SciTech Connect (OSTI)

    Parkhurst, MaryAnn; Szrom, Fran; Guilmette, Ray; Holmes, Tom; Cheng, Yung-Sung; Kenoyer, Judson L.; Collins, John W.; Sanderson, T. Ellory; Fliszar, Richard W.; Gold, Kenneth; Beckman, John C.; Long, Julie

    2004-10-19T23:59:59.000Z

    In a study designed to provide an improved scientific basis for assessing possible health effects from inhaling depleted uranium (DU) aerosols, a series of DU penetrators was fired at an Abrams tank and a Bradley fighting vehicle. A robust sampling system was designed to collect aerosols in this difficult environment and continuously monitor the sampler flow rates. Aerosols collected were analyzed for uranium concentration and particle size distribution as a function of time. They were also analyzed for uranium oxide phases, particle morphology, and dissolution in vitro. The resulting data provide input useful in human health risk assessments.

  12. Electrolytic process for preparing uranium metal

    DOE Patents [OSTI]

    Haas, Paul A. (Knoxville, TN)

    1990-01-01T23:59:59.000Z

    An electrolytic process for making uranium from uranium oxide using Cl.sub.2 anode product from an electrolytic cell to react with UO.sub.2 to form uranium chlorides. The chlorides are used in low concentrations in a melt comprising fluorides and chlorides of potassium, sodium and barium in the electrolytic cell. The electrolysis produces Cl.sub.2 at the anode that reacts with UO.sub.2 in the feed reactor to form soluble UCl.sub.4, available for a continuous process in the electrolytic cell, rather than having insoluble UO.sub.2 fouling the cell.

  13. ENDF-201: ENDF/B-VI summary documentation

    SciTech Connect (OSTI)

    Rose, P.F. (comp.)

    1991-10-01T23:59:59.000Z

    Responsibility for oversight of the ENDF/B Evaluated Nuclear Data file lies with the Cross Section Evaluation Working Group (CSEWG), which is comprised of representatives from various governmental and industrial laboratories in the United States. Individual evaluations are provided by scientists at several US laboratories, including significant contributions by scientists from all over the world. In addition, ENDF/B-VI includes for the first time complete evaluations for three materials that were provided from laboratories outside the US. All data are checked and reviewed by CSEWG, and the data file is maintained and issued by the National Nuclear Data Center at Brookhaven National Laboratory. The previous version of the library, ENDF/B-V, was issued in 1979, and two revisions to the data file were provided in subsequent years, the latest occurring in 1981. A total of 75 new or extensively modified neutron sublibrary evaluations are included in ENDF/B-VI, and are summarized in this document. One incident proton sublibrary is described for Fe{sup 56}. The remaining evaluations in ENDF/B-VI have been carried over from earlier versions of ENDF, and have been updated to reflect the new formats. The release of ENDF/B-VI was carried out between January and June of 1990, with groups of materials being released on tapes.'' Table 1 is an index to the evaluation summaries, and includes the material identification or MAT number, the responsible laboratory, and the tape'' number. These evaluations have been released without restrictions on their distribution or use.

  14. ENDF-201: ENDF/B-VI summary documentation

    SciTech Connect (OSTI)

    Rose, P.F. [comp.

    1991-10-01T23:59:59.000Z

    Responsibility for oversight of the ENDF/B Evaluated Nuclear Data file lies with the Cross Section Evaluation Working Group (CSEWG), which is comprised of representatives from various governmental and industrial laboratories in the United States. Individual evaluations are provided by scientists at several US laboratories, including significant contributions by scientists from all over the world. In addition, ENDF/B-VI includes for the first time complete evaluations for three materials that were provided from laboratories outside the US. All data are checked and reviewed by CSEWG, and the data file is maintained and issued by the National Nuclear Data Center at Brookhaven National Laboratory. The previous version of the library, ENDF/B-V, was issued in 1979, and two revisions to the data file were provided in subsequent years, the latest occurring in 1981. A total of 75 new or extensively modified neutron sublibrary evaluations are included in ENDF/B-VI, and are summarized in this document. One incident proton sublibrary is described for Fe{sup 56}. The remaining evaluations in ENDF/B-VI have been carried over from earlier versions of ENDF, and have been updated to reflect the new formats. The release of ENDF/B-VI was carried out between January and June of 1990, with groups of materials being released on ``tapes.`` Table 1 is an index to the evaluation summaries, and includes the material identification or MAT number, the responsible laboratory, and the ``tape`` number. These evaluations have been released without restrictions on their distribution or use.

  15. Implementation of MP{_}Lite for the VI Architecture

    SciTech Connect (OSTI)

    Weiyi Chen

    2002-12-31T23:59:59.000Z

    MP{_}Lite is a light weight message-passing library designed to deliver the maximum performance to applications in a portable and user friendly manner. The Virtual Interface (VI) architecture is a user-level communication protocol that bypasses the operating system to provide much better performance than traditional network architectures. By combining the high efficiency of MP{_}Lite and high performance of the VI architecture, they are able to implement a high performance message-passing library that has much lower latency and better throughput. The design and implementation of MP{_}Lite for M-VIA, which is a modular implementation of the VI architecture on Linux, is discussed in this thesis. By using the eager protocol for sending short messages, MP{_}Lite M-VIA has much lower latency on both Fast Ethernet and Gigabit Ethernet. The handshake protocol and RDMA mechanism provides double the throughput that MPICH can deliver for long messages. MP{_}Lite M-VIA also has the ability to channel-bonding multiple network interface cards to increase the potential bandwidth between nodes. Using multiple Fast Ethernet cards can double or even triple the maximum throughput without increasing the cost of a PC cluster greatly.

  16. VI Symposium of Specialists in Electric Operational and Expansion Planning -VI SEPOPE, May 24-29,1998, Bahia, Brazil POWER SYSTEM PLANNING IN THE SOUTH AMERICA

    E-Print Network [OSTI]

    Catholic University of Chile (Universidad Católica de Chile)

    -29,1998, Bahia, Brazil POWER SYSTEM PLANNING IN THE SOUTH AMERICA ELECTRIC MARKET RESTRUCTURING Hugh Rudnick for the electricity infrastructure than for the transport one. Both integrate different components (whileVI Symposium of Specialists in Electric Operational and Expansion Planning - VI SEPOPE, May 24

  17. Uranium isotopic composition and uranium concentration in special reference material SRM A (uranium in KCl/LiCl salt matrix)

    SciTech Connect (OSTI)

    Graczyk, D.G.; Essling, A.M.; Sabau, C.S.; Smith, F.P.; Bowers, D.L.; Ackerman, J.P.

    1997-07-01T23:59:59.000Z

    To help assure that analysis data of known quality will be produced in support of demonstration programs at the Fuel Conditioning Facility at Argonne National Laboratory-West (Idaho Falls, ID), a special reference material has been prepared and characterized. Designated SRM A, the material consists of individual units of LiCl/KCl eutectic salt containing a nominal concentration of 2.5 wt. % enriched uranium. Analyses were performed at Argonne National Laboratory-East (Argonne, IL) to determine the uniformity of the material and to establish reference values for the uranium concentration and uranium isotopic composition. Ten units from a batch of approximately 190 units were analyzed by the mass spectrometric isotope dilution technique to determine their uranium concentration. These measurements provided a mean value of 2.5058 {+-} 0.0052 wt. % U, where the uncertainty includes estimated limits to both random and systematic errors that might have affected the measurements. Evidence was found of a small, apparently random, non-uniformity in uranium content of the individual SRM A units, which exhibits a standard deviation of 0.078% of the mean uranium concentration. Isotopic analysis of the uranium from three units, by means of thermal ionization mass spectrometry with a special, internal-standard procedure, indicated that the uranium isotopy is uniform among the pellets with a composition corresponding to 0.1115 {+-} 0.0006 wt. % {sup 234}U, 19.8336 {+-} 0.0059 wt. % {sup 235}U, 0.1337 {+-} 0.0006 wt. % {sup 236}U, and 79.9171 {+-} 0.0057 wt. % {sup 238}U.

  18. Exposing illegal timber Nov 10, 2003

    E-Print Network [OSTI]

    Exposing illegal timber trade Melvin Goh Nov 10, 2003 Email this article Printer friendly page Just example of illegal timber being smuggled into Sarawak and we are doing everything we can to stop it with assistance from other authorities. As to allegations that huge amount of illegal timber is being shipped

  19. Microstructural analyses of Cr(VI) speciation in chromite ore processing Residue (COPR)

    SciTech Connect (OSTI)

    CHRYSOCHOOU, MARIA; FAKRA, SIRINE C .; Marcus, Matthew A.; Moon, Deok Hyun; Dermatas, Dimitris

    2010-03-01T23:59:59.000Z

    The speciation and distribution of Cr(VI) in the solid phase was investigated for two types of chromite ore processing residue (COPR) found at two deposition sites in the United States: gray-black (GB) granular and hard brown (HB) cemented COPR. COPR chemistry and mineralogy were investigated using micro-X-ray absorption spectroscopy and micro-X-ray diffraction, complemented by laboratory analyses. GB COPR contained 30percent of its total Cr(VI) (6000 mg/kg) as large crystals(>20 ?m diameter) of a previously unreported Na-rich analog of calcium aluminum chromate hydrates. These Cr(VI)-rich phases are thought to be vulnerable to reductive and pH treatments. More than 50percent of the Cr(VI) was located within nodules, not easily accessible to dissolved reductants, and bound to Fe-rich hydrogarnet, hydrotalcite, and possibly brucite. These phases are stable over a large pH range, thus harder to dissolve. Brownmilleritewasalso likely associated with physical entrapment of Cr(VI) in the interior of nodules. HB COPR contained no Cr(VI)-rich phases; all Cr(VI) was diffuse within the nodules and absent from the cementing matrix, with hydrogarnet and hydrotalcite being the main Cr(VI) binding phases. Treatment ofHBCOPRis challenging in terms of dissolving the acidity-resistant, inaccessible Cr(VI) compounds; the same applies to ~;;50percent of Cr(VI) in GB COPR.

  20. Mica Surfaces Stabilize Pentavalent Uranium. | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Ilton ES, A Haiduc, CL Cahill, and AR Felmy.2005."Mica Surfaces Stabilize Pentavalent Uranium."Inorganic Chemistry 44(9):2986-2988. Authors: ES Ilton A Haiduc CL Cahill AR...

  1. Process for reducing beta activity in uranium

    DOE Patents [OSTI]

    Briggs, Gifford G. (Cincinnatti, OH); Kato, Takeo R. (Cincinnatti, OH); Schonegg, Edward (Cleves, OH)

    1986-01-01T23:59:59.000Z

    This invention is a method for lowering the beta radiation hazards associated with the casting of uranium. The method reduces the beta radiation emitted from the as-cast surfaces of uranium ingots. The method also reduces the amount of beta radiation emitters retained on the interiors of the crucibles that have been used to melt the uranium charges and which have undergone cleaning in a remote handling facility. The lowering of the radioactivity is done by scavenging the beta emitters from the molten uranium with a molten mixture containing the fluorides of magnesium and calcium. The method provides a means of collection and disposal of the beta emitters in a manner that reduces radiation exposure to operating personnel in the work area where the ingots are cast and processed.

  2. Desorption of uranium from amidoxime fiber adsorbent

    SciTech Connect (OSTI)

    Goto, Akira; Morooka, Shigeharu; Fukamachi, Masakazu; Kusakabe, Katsuki (Kyushu Univ., Fukuoka (Japan)); Kago, Tokihiro (Towa Univ., Fukuoka (Japan))

    1993-10-01T23:59:59.000Z

    An amidoxime fibrous adsorbent is contacted with uranium-enriched seawater (10 ppm); about 10 mg uranium is loaded per 1 g dry fiber. Then the rate and yield of uranium desorption from the fiber are determined with various eluents. Acid solutions are superior to alkali carbonate solutions as eluents. With a 0.1 mol[center dot]L[sup [minus]1] HCl solution, desorption is completed in 2 hours regardless of the presence of uranium in the leaching solution up to 15 ppm ([approx]6 [times] 10[sup [minus]5]mol[center dot]L[sup [minus]1]). Serial operation of the adsorption-desorption cycle four times does not affect desorption efficiency, but the addition of heavy metal ions to the eluent at a level of 1.8 [times] 10[sup [minus]3]mol[center dot]L[sup [minus]1] significantly decreases desorption efficiency. 13 refs., 5 figs., 1 tab.

  3. Investigation of Trace Uranium in Biological Matrices

    E-Print Network [OSTI]

    Miller, James Christopher

    2013-05-31T23:59:59.000Z

    U.S. Department of Energy synthetic urine quality assurance standards from an inter-laboratory exercise in 2012. The separation apparatus was able to consistently separate uranium from the synthetic urine solutions with a consistent recovery between...

  4. Innovative design of uranium startup fast reactors

    E-Print Network [OSTI]

    Fei, Tingzhou

    2012-01-01T23:59:59.000Z

    Sodium Fast Reactors are one of the three candidates of GEN-IV fast reactors. Fast reactors play an important role in saving uranium resources and reducing nuclear wastes. Conventional fast reactors rely on transuranic ...

  5. In situ remediation of uranium contaminated groundwater

    SciTech Connect (OSTI)

    Dwyer, B.P.; Marozas, D.C. [Sandia National Labs., Albuquerque, NM (United States)

    1997-12-31T23:59:59.000Z

    In an effort to develop cost-efficient techniques for remediating uranium contaminated groundwater at DOE Uranium Mill Tailing Remedial Action (UMTRA) sites nationwide, Sandia National Laboratories (SNL) deployed a pilot scale research project at an UMTRA site in Durango, CO. Implementation included design, construction, and subsequent monitoring of an in situ passive reactive barrier to remove Uranium from the tailings pile effluent. A reactive subsurface barrier is produced by emplacing a reactant material (in this experiment - various forms of metallic iron) in the flow path of the contaminated groundwater. Conceptually the iron media reduces and/or adsorbs uranium in situ to acceptable regulatory levels. In addition, other metals such as Se, Mo, and As have been removed by the reductive/adsorptive process. The primary objective of the experiment was to eliminate the need for surface treatment of tailing pile effluent. Experimental design, and laboratory and field preliminary results are discussed with regard to other potential contaminated groundwater treatment applications.

  6. In situ remediation of uranium contaminated groundwater

    SciTech Connect (OSTI)

    Dwyer, B.P.; Marozas, D.C.

    1997-02-01T23:59:59.000Z

    In an effort to develop cost-efficient techniques for remediating uranium contaminated groundwater at DOE Uranium Mill Tailing Remedial Action (UMTRA) sites nationwide, Sandia National Laboratories (SNL) deployed a pilot scale research project at an UMTRA site in Durango, CO. Implementation included design, construction, and subsequent monitoring of an in situ passive reactive barrier to remove Uranium from the tailings pile effluent. A reactive subsurface barrier is produced by emplacing a reactant material (in this experiment various forms of metallic iron) in the flow path of the contaminated groundwater. Conceptually the iron media reduces and/or adsorbs uranium in situ to acceptable regulatory levels. In addition, other metals such as Se, Mo, and As have been removed by the reductive/adsorptive process. The primary objective of the experiment was to eliminate the need for surface treatment of tailing pile effluent. Experimental design, and laboratory and field results are discussed with regard to other potential contaminated groundwater treatment applications.

  7. Process for reducing beta activity in uranium

    DOE Patents [OSTI]

    Briggs, G.G.; Kato, T.R.; Schonegg, E.

    1985-04-11T23:59:59.000Z

    This invention is a method for lowering the beta radiation hazards associated with the casting of uranium. The method reduces the beta radiation emitted from the as-cast surfaces of uranium ingots. The method also reduces the amount of beta radiation emitters retained on the interiors of the crucibles that have been used to melt the uranium charges and which undergone cleaning in a remote handling facility. The lowering of the radioactivity is done by scavenging the beta emitters from the molten uranium with a molten mixture containing the fluorides of magnesium and calcium. The method provides a means of collection and disposal of the beta emitters in a manner that reduces radiation exposure to operating personnel in the work area where the ingots are cast and processed. 5 tabs.

  8. Depleted uranium: A DOE management guide

    SciTech Connect (OSTI)

    NONE

    1995-10-01T23:59:59.000Z

    The U.S. Department of Energy (DOE) has a management challenge and financial liability in the form of 50,000 cylinders containing 555,000 metric tons of depleted uranium hexafluoride (UF{sub 6}) that are stored at the gaseous diffusion plants. The annual storage and maintenance cost is approximately $10 million. This report summarizes several studies undertaken by the DOE Office of Technology Development (OTD) to evaluate options for long-term depleted uranium management. Based on studies conducted to date, the most likely use of the depleted uranium is for shielding of spent nuclear fuel (SNF) or vitrified high-level waste (HLW) containers. The alternative to finding a use for the depleted uranium is disposal as a radioactive waste. Estimated disposal costs, utilizing existing technologies, range between $3.8 and $11.3 billion, depending on factors such as applicability of the Resource Conservation and Recovery Act (RCRA) and the location of the disposal site. The cost of recycling the depleted uranium in a concrete based shielding in SNF/HLW containers, although substantial, is comparable to or less than the cost of disposal. Consequently, the case can be made that if DOE invests in developing depleted uranium shielded containers instead of disposal, a long-term solution to the UF{sub 6} problem is attained at comparable or lower cost than disposal as a waste. Two concepts for depleted uranium storage casks were considered in these studies. The first is based on standard fabrication concepts previously developed for depleted uranium metal. The second converts the UF{sub 6} to an oxide aggregate that is used in concrete to make dry storage casks.

  9. The ultimate disposition of depleted uranium

    SciTech Connect (OSTI)

    Lemons, T.R. [Uranium Enrichment Organization, Oak Ridge, TN (United States)

    1991-12-31T23:59:59.000Z

    Depleted uranium (DU) is produced as a by-product of the uranium enrichment process. Over 340,000 MTU of DU in the form of UF{sub 6} have been accumulated at the US government gaseous diffusion plants and the stockpile continues to grow. An overview of issues and objectives associated with the inventory management and the ultimate disposition of this material is presented.

  10. Investigation of Trace Uranium in Biological Matrices 

    E-Print Network [OSTI]

    Miller, James Christopher

    2013-05-31T23:59:59.000Z

    . This monitoring is often multi-faceted and typically involves an air sampling and biological sampling regime. The regime depends on the potential for exposures, the materials and chemical compounds being used, and the facility history. Specifically... Y-12 led the early US uranium enrichment programs, it also pioneered early uranium bioassay.[8] Likewise, the 5 Savannah River Site (SRS) pioneered plutonium bioassay techniques.[9] From these programs, techniques were developed to detect...

  11. BIOREMEDIATION OF URANIUM CONTAMINATED SOILS AND WASTES.

    SciTech Connect (OSTI)

    FRANCIS,A.J.

    1998-09-17T23:59:59.000Z

    Contamination of soils, water, and sediments by radionuclides and toxic metals from uranium mill tailings, nuclear fuel manufacturing and nuclear weapons production is a major concern. Studies of the mechanisms of biotransformation of uranium and toxic metals under various microbial process conditions has resulted in the development of two treatment processes: (i) stabilization of uranium and toxic metals with reduction in waste volume and (ii) removal and recovery of uranium and toxic metals from wastes and contaminated soils. Stabilization of uranium and toxic metals in wastes is accomplished by exploiting the unique metabolic capabilities of the anaerobic bacterium, Clostridium sp. The radionuclides and toxic metals are solubilized by the bacteria directly by enzymatic reductive dissolution, or indirectly due to the production of organic acid metabolites. The radionuclides and toxic metals released into solution are immobilized by enzymatic reductive precipitation, biosorption and redistribution with stable mineral phases in the waste. Non-hazardous bulk components of the waste such as Ca, Fe, K, Mg and Na released into solution are removed, thus reducing the waste volume. In the second process uranium and toxic metals are removed from wastes or contaminated soils by extracting with the complexing agent citric acid. The citric-acid extract is subjected to biodegradation to recover the toxic metals, followed by photochemical degradation of the uranium citrate complex which is recalcitrant to biodegradation. The toxic metals and uranium are recovered in separate fractions for recycling or for disposal. The use of combined chemical and microbiological treatment process is more efficient than present methods and should result in considerable savings in clean-up and disposal costs.

  12. Material property correlations for uranium mononitride

    E-Print Network [OSTI]

    Hayes, Steven Lowe

    1989-01-01T23:59:59.000Z

    . 1 1770 - 2083 20. 7 - 34. 4 158, 1773 13-54 Test Environment Fuel Manafact- uring Route Test conducted in vaccuum (10~-5 ton) Cold pressed and sintered. Test conducted in 200 torr nitrogen atmosphere Isostatically Hot Pressed. Test... conductivity, high uranium density, stable irradiation behavior and compatibility with liquid metal coolants and refractory metal structural materials all combine to make uranium mononitride (UN) a very attractive nuclear fuel for use in high temperature...

  13. Development of a biomarker for Geobacter activity and strain composition: Proteogenomic analysis of the citrate synthase protein during bioremediation of U(VI)

    E-Print Network [OSTI]

    Wilkins, M.J.

    2010-01-01T23:59:59.000Z

    during  in  situ  bioremediation  of  uranium?contaminated in  situ  uranium  bioremediation field site.  Appl Environ during  stimulated  uranium  bioremediation.  Appl Environ 

  14. Electrochemical method of producing eutectic uranium alloy and apparatus

    DOE Patents [OSTI]

    Horton, James A. (Livermore, CA); Hayden, H. Wayne (Oakridge, TN)

    1995-01-01T23:59:59.000Z

    An apparatus and method for continuous production of liquid uranium alloys through the electrolytic reduction of uranium chlorides. The apparatus includes an electrochemical cell formed from an anode shaped to form an electrolyte reservoir, a cathode comprising a metal, such as iron, capable of forming a eutectic uranium alloy having a melting point less than the melting point of pure uranium, and molten electrolyte in the reservoir comprising a chlorine or fluorine containing salt and uranium chloride. The method of the invention produces an eutectic uranium alloy by creating an electrolyte reservoir defined by a container comprising an anode, placing an electrolyte in the reservoir, the electrolyte comprising a chlorine or fluorine containing salt and uranium chloride in molten form, positioning a cathode in the reservoir where the cathode comprises a metal capable of forming an uranium alloy having a melting point less than the melting point of pure uranium, and applying a current between the cathode and the anode.

  15. Conversion and Blending Facility Highly enriched uranium to low enriched uranium as uranium hexafluoride. Revision 1

    SciTech Connect (OSTI)

    NONE

    1995-07-05T23:59:59.000Z

    This report describes the Conversion and Blending Facility (CBF) which will have two missions: (1) convert surplus HEU materials to pure HEU UF{sub 6} and a (2) blend the pure HEU UF{sub 6} with diluent UF{sub 6} to produce LWR grade LEU-UF{sub 6}. The primary emphasis of this blending be to destroy the weapons capability of large, surplus stockpiles of HEU. The blended LEU product can only be made weapons capable again by the uranium enrichment process. The chemical and isotopic concentrations of the blended LEU product will be held within the specifications required for LWR fuel. The blended LEU product will be offered to the United States Enrichment Corporation (USEC) to be sold as feed material to the commercial nuclear industry.

  16. Field-based detection and monitoring of uranium in contaminated groundwater using two immunosensors

    SciTech Connect (OSTI)

    Melton, S.J.; Yu, H.; Williams, K.H.; Morris, S.A.; Long, P.E.; Blake, D.A.

    2009-05-01T23:59:59.000Z

    Field-based monitoring of environmental contaminants has long been a need for environmental scientists. Described herein are two kinetic exclusion-based immunosensors, a field portable sensor (FPS) and an inline senor, that were deployed at the Integrated Field Research Challenge Site of the U.S. Department of Energy in Rifle, CO. Both sensors utilized a monoclonal antibody that binds to a U(VI)-dicarboxyphenanthroline complex (DCP) in a kinetic exclusion immunoassay format. These sensors were able to monitor changes of uranium in groundwater samples from {approx} 1 {micro}M to below the regulated drinking water limit of 126 nM (30 ppb). The FPS is a battery-operated sensor platform that can determine the uranium level in a single sample in 5-10 min, if the instrument has been previously calibrated with standards. The average minimum detection level (MDL) in this assay was 0.33 nM (79 ppt), and the MDL in the sample (based on a 1:200?1:400 dilution) was 66?132 nM (15.7?31.4 ppb). The inline sensor, while requiring a grounded power source, has the ability to autonomously analyze multiple samples in a single experiment. The average MDL in this assay was 0.12 nM (29 ppt), and the MDL in the samples (based on 1:200 or 1:400 dilutions) was 24?48 nM (5.7?11.4 ppb). Both sensor platforms showed an acceptable level of agreement (r{sup 2} = 0.94 and 0.76, for the inline and FPS, respectively) with conventional methods for uranium quantification.

  17. Summary of the planning, management, and evaluation process for the Geothermal Program Review VI conference

    SciTech Connect (OSTI)

    Not Available

    1988-10-01T23:59:59.000Z

    The purpose of this document is to present an overview of the planning, facilitation, and evaluation process used to conduct the Geothermal Program Review VI (PR VI) conference. This document was also prepared to highlight lessons learned from PR VI and, by utilizing the evaluation summaries and recommendations, be used as a planning tool for PR VII. The conference, entitled Beyond Goals and Objectives,'' was sponsored by the US Department of Energy's (DOE) Geothermal Technology Division (GTD), PR VI was held in San Francisco, California on April 19--21, 1988 and was attended by 127 participants. PR VI was held in conjunction with the National Geothermal Association's (NGA) Industry Round Table. This document presents a brief summary of the activities, responsibilities, and resources for implementing the PR VI meeting and provides recommendations, checklists, and a proposed schedule for assisting in planning PR VII.

  18. Method of removing niobium from uranium-niobium alloy

    SciTech Connect (OSTI)

    Pollock, E.N.; Schlier, D.S.; Shinopulos, G.

    1992-01-28T23:59:59.000Z

    This patent describes a method of removing niobium from a uranium-niobium alloy. It comprises dissolving the uranium-niobium alloy metal pieces in a first aqueous solution containing an acid selected from the group consisting of hydrochloric acid and sulfuric acid and fluoboric acid as a catalyst to provide a second aqueous solution, which includes uranium (U{sup +4}), acid radical ions, the acids insolubles including uranium oxides and niobium oxides; adding nitric acid to the insolubles to oxidize the niobium oxides to yield niobic acid and to complete the solubilization of any residual uranium; and separating the niobic acid from the nitric acid and solubilized uranium.

  19. Method for making graded I-III-VI.sub.2 semiconductors and solar cell obtained thereby

    DOE Patents [OSTI]

    Devaney, Walter E. (Seattle, WA)

    1987-08-04T23:59:59.000Z

    Improved cell photovoltaic conversion efficiencies are obtained by the simultaneous elemental reactive evaporation process of Mickelsen and Chen for making semiconductors by closer control of the evaporation rates and substrate temperature during formation of the near contact, bulk, and near junction regions of a graded I-III-VI.sub.2, thin film, semiconductor, such as CuInSe.sub.2 /(Zn,Cd)S or another I-III-VI.sub.2 /II-VI heterojunction.

  20. Field-based detection and monitoring of uranium in contaminated groundwater using two immunosensors

    E-Print Network [OSTI]

    Melton, S.J.

    2010-01-01T23:59:59.000Z

    D. R. , Sustained removal of uranium from contaminated9. 18. Brina, R. , Uranium removal from contaminated water

  1. Detection of hexavalent uranium with inline and field-portable immunosensors

    E-Print Network [OSTI]

    Melton, Scott J.

    2009-01-01T23:59:59.000Z

    were able detect the removal of uranium from the groundwaterDR (2008) Sustained removal of uranium from contaminated

  2. Molecular analysis of phosphate limitation in Geobacteraceae during the bioremediation of a uranium-contaminated aquifer

    E-Print Network [OSTI]

    N'Guessan, L.A.

    2010-01-01T23:59:59.000Z

    DR (2008). Sustained Removal of Uranium From ContaminatedKomlos J et al (2007). Uranium removal from groundwater via

  3. Method of manufacturing semiconductor having group II-group VI compounds doped with nitrogen

    DOE Patents [OSTI]

    Compaan, Alvin D.; Price, Kent J.; Ma, Xianda; Makhratchev, Konstantin

    2005-02-08T23:59:59.000Z

    A method of making a semiconductor comprises depositing a group II-group VI compound onto a substrate in the presence of nitrogen using sputtering to produce a nitrogen-doped semiconductor. This method can be used for making a photovoltaic cell using sputtering to apply a back contact layer of group II-group VI compound to a substrate in the presence of nitrogen, the back coating layer being doped with nitrogen. A semiconductor comprising a group II-group VI compound doped with nitrogen, and a photovoltaic cell comprising a substrate on which is deposited a layer of a group II-group VI compound doped with nitrogen, are also included.

  4. Integrated Ecogenomics Study for Bioremediation of Cr(VI) at Hanford 100H Area

    E-Print Network [OSTI]

    Chakraborty, Romy

    2008-01-01T23:59:59.000Z

    ecogenomics study for bioremediation of Cr(VI) at HanfordRegenesis In-situ bioremediation at Hanford 100H area ??

  5. Molecular Interactions of Plutonium(VI) with Synthetic Manganese-Substituted Goethite

    E-Print Network [OSTI]

    Hu, Yung-Jin

    2011-01-01T23:59:59.000Z

    VI) with the Iron Oxide Goethite, University of California,Values for Synthetic Goethite and Pyrolusite" submitted tothe two Mn-substituted goethite minerals used in this study.

  6. Nonlinear Spinor Fields in Bianchi type-$VI_0$ spacetime

    E-Print Network [OSTI]

    Bijan Saha

    2015-04-15T23:59:59.000Z

    Within the scope of Bianchi type-$VI_0$ space time we study the role of spinor field on the evolution of the Universe. It is found that the presence of nontrivial non-diagonal components of energy-momentum tensor of the spinor field plays vital role on the evolution of the Universe. As a result of their mutual influence the invariants constructed from the bilinear forms of the spinor field become trivial, thus giving rise to a massless and linear spinor field Lagrangian. This result shows that the spinor field is highly sensitive to the gravitational one.

  7. Baseline risk assessment of ground water contamination at the uranium mill tailings site near Canonsburg, Pennsylvania

    SciTech Connect (OSTI)

    Not Available

    1994-09-01T23:59:59.000Z

    This baseline risk assessment evaluates potential impacts to public health and the environment resulting from ground water contamination from past activities at the former uranium processing site in Canonsburg, Pennsylvania. The US Department of Energy Uranium Mill Tailings Remedial Action (UMTRA) Project has placed contaminated material from this site in an on-site disposal cell. Currently, the UMTRA Project is evaluating ground water contamination. This risk assessment is the first document specific to this site for the UMTRA Ground Water Project. Currently, no domestic or drinking water well tap into contaminated ground water of the two distinct ground water units: the unconsolidated materials and the bedrock. Because there is no access, no current health or environmental risks are associated with the direct use of the contaminated ground water. However, humans and ecological organisms could be exposed to contaminated ground water if a domestic well were to be installed in the unconsolidated materials in that part of the site being considered for public use (Area C). The first step is evaluating ground water data collected from monitor wells at the site. For the Canonsburg site, this evaluation showed the contaminants in ground water exceeding background in the unconsolidated materials in Area C are ammonia, boron, calcium, manganese, molybdenum, potassium, strontium, and uranium.

  8. Prospects for the recovery of uranium from seawater

    E-Print Network [OSTI]

    Best, F. R.

    1980-01-01T23:59:59.000Z

    A computer program entitled URPE (Uranium Recovery Performance and Economics) has been developed to simulate the engineering performance and provide an economic analysis O of a plant recovering uranium from seawater. The ...

  9. EA-1290: Disposition of Russian Federation Titled Natural Uranium

    Broader source: Energy.gov [DOE]

    This EA evaluates the potential environmental impacts of a proposal to transport up to an average of 9,000 metric tons per year of natural uranium as uranium hexafluoride (UF6) from the United...

  10. Assessments of long-term uranium supply availability

    E-Print Network [OSTI]

    Zaterman, Daniel R

    2009-01-01T23:59:59.000Z

    The future viability of nuclear power will depend on the long-term availability of uranium. A two-form uranium supply model was used to estimate the date at which peak production will occur. The model assumes a constant ...

  11. Y-12 and the super enriched Uranium 235?

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    "super enriched Uranium 235" Ken Bernander called me to say that he had read in the newspaper about the 100 milligrams of uranium oxide that is 99.999% U-235. He was chuckling when...

  12. Fabrication and Characterization of Uranium-based High Temperature...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Fabrication and Characterization of Uranium-based High Temperature Reactor Fuel June 01, 2013 The Uranium Fuel Development Laboratory is a modern R&D scale lab for the fabrication...

  13. RESOLUTION OF URANIUM ISOTOPES WITH KINETIC PHOSPHORESCENCE ANALYSIS

    SciTech Connect (OSTI)

    Miley, Sarah M.; Hylden, Anne T.; Friese, Judah I.

    2013-04-01T23:59:59.000Z

    This study was conducted to test the ability of the Chemchek™ Kinetic Phosphorescence Analyzer Model KPA-11 with an auto-sampler to resolve the difference in phosphorescent decay rates of several different uranium isotopes, and therefore identify the uranium isotope ratios present in a sample. Kinetic phosphorescence analysis (KPA) is a technique that provides rapid, accurate, and precise determination of uranium concentration in aqueous solutions. Utilizing a pulsed-laser source to excite an aqueous solution of uranium, this technique measures the phosphorescent emission intensity over time to determine the phosphorescence decay profile. The phosphorescence intensity at the onset of decay is proportional to the uranium concentration in the sample. Calibration with uranium standards results in the accurate determination of actual concentration of the sample. Different isotopes of uranium, however, have unique properties which should result in different phosphorescence decay rates seen via KPA. Results show that a KPA is capable of resolving uranium isotopes.

  14. abandoned uranium mines: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    residents. 3.1.1 On-Site Recreation Since most uranium locations are on federal lands 91 Depleted Uranium Technical Brief Environmental Sciences and Ecology Websites Summary: and...

  15. Demonstration of jackhammer incorporating depleted uranium

    SciTech Connect (OSTI)

    Fischer, L E; Hoard, R W; Carter, D L; Saculla, M D; Wilson, G V

    2000-04-01T23:59:59.000Z

    The United States Government currently has an abundance of depleted uranium (DU). This surplus of about 1 billion pounds is the result of an enrichment process using gaseous diffusion to produce enriched and depleted uranium. The enriched uranium has been used primarily for either nuclear weapons for the military or nuclear fuel for the commercial power industry. Most of the depleted uranium remains at the enrichment process plants in the form of depleted uranium hexafluoride (DUF{sub 6}). The Department of Energy (DOE) recently began a study to identify possible commercial applications for the surplus material. One of these potential applications is to use the DU in high-density strikers/hammers in pneumatically driven tools, such as jack hammers and piledrivers to improve their impulse performance. The use of DU could potentially increase tunneling velocity and excavation into target materials with improved efficiency. This report describes the efforts undertaken to analyze the particulars of using DU in two specific striking applications: the jackhammer and chipper tool.

  16. Geothermal Program Review VI: proceedings. Beyond goals and objectives

    SciTech Connect (OSTI)

    Not Available

    1988-01-01T23:59:59.000Z

    Program Review VI was comprised of six sessions, including an opening session, four technical sessions that addressed each of the major DOE research areas, and a session on special issues. The technical sessions were on Hydrothermal, Hot Dry Rock, Geopressured and Magma resources. Presenters in the technical sessions discussed their R and D activities within the context of specific GTD Programmatic Objectives for that technology, their progress toward achieving those objectives, and the value of those achievements to industry. The ''Special Issues'' presentations addressed several topics such as the interactions between government and industry on geothermal energy R and D; the origin and basis for the programmatic objectives analytical computer model; and international marketing opportunities for US geothermal equipment and services. The unique aspect of Program Review VI was that it was held in conjunction with the National Geothermal Association's Industry Round Table on Federal R and D. The Round Table provided a forum for open and lively discussions between industry and government researchers and gave industry an opportunity to convey their needs and perspectives on DOE's research programs. These discussions also provided valuable information to DOE regarding industry's priorities and directions.

  17. Monitoring Uranium Transformations Determined by the Evolution of Biogeochemical Processes

    SciTech Connect (OSTI)

    Marsh, Terence L.

    2013-07-30T23:59:59.000Z

    Our contribution to the larger project (ANL) was the phylogenetic analysis of evolved communities capable of reducing metals including uranium.

  18. The radioactive Substances (Uranium and Thorium) Exemption Order 1962 

    E-Print Network [OSTI]

    Joseph, Keith

    1962-01-01T23:59:59.000Z

    STATUTORY INSTRUMENTS 1962 No.2710 ATOMIC ENERGY AND RADIOACTIVE SUBSTANCES The Radioactive Substances (Uranium and Thorium) Exemption Order 1962...

  19. Modeling Uranium-Proton Ion Exchange in Biosorption

    E-Print Network [OSTI]

    Volesky, Bohumil

    seaweed biomass was used to remove the heavy metal uranium from the aqueous solution. Uranium biosorptionModeling Uranium-Proton Ion Exchange in Biosorption J I N B A I Y A N G A N D B O H U M I L V O L E, Quebec, Canada H3A 2B2 Biosorption of uranium metal ions by a nonliving protonated Sargassum fluitans

  20. Depleted Uranium in Kosovo Post-Conflict Environmental Assessment

    E-Print Network [OSTI]

    Unep Scientific; Mission Kosovo

    2.1 UNEP’s role in post-conflict environmental assessment................................................9 2.2 Depleted uranium............................................................10

  1. Tracking the Sun VI: An Historical Summary of the Installed Price of Photovoltaics in the United States from 1998 to 2012

    E-Print Network [OSTI]

    Barbose, Galen

    2014-01-01T23:59:59.000Z

    Laboratory. Tracking the Sun VI: The Installed Price ofRange ?10 kW Tracking the Sun VI: The Installed Price ofRange ?10 kW Tracking the Sun VI: The Installed Price of

  2. Tables des principaux minerais d'uranium et de thorium

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    233 Tables des principaux minerais d'uranium et de thorium Par B. SZILARD [Faculté des Sciences de minerais d'uranium et de thorium avec leurs données les plus importantes, telles que la com- position, la teneur en uranium et en thorium, la provenance et quelques indications générales. La liste ne prétend pas

  3. Estimating terrestrial uranium and thorium by antineutrino flux measurements

    E-Print Network [OSTI]

    Mcdonough, William F.

    Estimating terrestrial uranium and thorium by antineutrino flux measurements Stephen T. Dye, and approved November 16, 2007 (received for review July 11, 2007) Uranium and thorium within the Earth produce of uranium and thorium concentrations in geological reservoirs relies largely on geochemi- cal model

  4. Microbial Janitors: Enabling natural microbes to clean up uranium contamination

    E-Print Network [OSTI]

    of Energy's Environmental Remediation Sciences Program. Q: How can uranium be removed or neutralized so in the contaminated subsurface and engineering the subsurface environment to stimulate nitrate removal and uraniumMicrobial Janitors: Enabling natural microbes to clean up uranium contamination Oak Ridge

  5. Appendix IV. Risks Associated with Conventional Uranium Milling Introduction

    E-Print Network [OSTI]

    ", uranium is removed from the processed ore with sulfuric acid. Sodium chlorate is also addedAppendix IV. Risks Associated with Conventional Uranium Milling Operations Introduction Although uranium mill tailings are considered byproduct materials under the AEA and not TENORM, EPA's Science

  6. Plutonium recovery from spent reactor fuel by uranium displacement

    DOE Patents [OSTI]

    Ackerman, J.P.

    1992-03-17T23:59:59.000Z

    A process is described for separating uranium values and transuranic values from fission products containing rare earth values when the values are contained together in a molten chloride salt electrolyte. A molten chloride salt electrolyte with a first ratio of plutonium chloride to uranium chloride is contacted with both a solid cathode and an anode having values of uranium and fission products including plutonium. A voltage is applied across the anode and cathode electrolytically to transfer uranium and plutonium from the anode to the electrolyte while uranium values in the electrolyte electrolytically deposit as uranium metal on the solid cathode in an amount equal to the uranium and plutonium transferred from the anode causing the electrolyte to have a second ratio of plutonium chloride to uranium chloride. Then the solid cathode with the uranium metal deposited thereon is removed and molten cadmium having uranium dissolved therein is brought into contact with the electrolyte resulting in chemical transfer of plutonium values from the electrolyte to the molten cadmium and transfer of uranium values from the molten cadmium to the electrolyte until the first ratio of plutonium chloride to uranium chloride is reestablished.

  7. EPA Uranium Program Update Loren W. Setlow and

    E-Print Network [OSTI]

    EPA Uranium Program Update Loren W. Setlow and Reid J. Rosnick Environmental Protection Agency Office of Radiation and Indoor Air (6608J) Washington, DC 20460 NMA/NRC Uranium Recovery Workshop April 30, 2008 #12;2 Overview EPA Radiation protection program Uranium reports and abandoned mine lands

  8. Plutonium recovery from spent reactor fuel by uranium displacement

    DOE Patents [OSTI]

    Ackerman, John P. (Downers Grove, IL)

    1992-01-01T23:59:59.000Z

    A process for separating uranium values and transuranic values from fission products containing rare earth values when the values are contained together in a molten chloride salt electrolyte. A molten chloride salt electrolyte with a first ratio of plutonium chloride to uranium chloride is contacted with both a solid cathode and an anode having values of uranium and fission products including plutonium. A voltage is applied across the anode and cathode electrolytically to transfer uranium and plutonium from the anode to the electrolyte while uranium values in the electrolyte electrolytically deposit as uranium metal on the solid cathode in an amount equal to the uranium and plutonium transferred from the anode causing the electrolyte to have a second ratio of plutonium chloride to uranium chloride. Then the solid cathode with the uranium metal deposited thereon is removed and molten cadmium having uranium dissolved therein is brought into contact with the electrolyte resulting in chemical transfer of plutonium values from the electrolyte to the molten cadmium and transfer of uranium values from the molten cadmium to the electrolyte until the first ratio of plutonium chloride to uranium chloride is reestablished.

  9. Standard Review Plan for In Situ Leach Uranium

    E-Print Network [OSTI]

    NUREG-1569 Standard Review Plan for In Situ Leach Uranium Extraction License Applications Final Washington, DC 20555-0001 #12;NUREG-1569 Standard Review Plan for In Situ Leach Uranium Extraction License OF A STANDARD REVIEW PLAN (NUREG­1569) FOR STAFF REVIEWS FOR IN SITU LEACH URANIUM EXTRACTION LICENSE

  10. Uranium Mill Tailings Remedial Action Project surface project management plan

    SciTech Connect (OSTI)

    Not Available

    1994-09-01T23:59:59.000Z

    This Project Management Plan describes the planning, systems, and organization that shall be used to manage the Uranium Mill Tailings Remedial Action Project (UMTRA). US DOE is authorized to stabilize and control surface tailings and ground water contamination at 24 inactive uranium processing sites and associated vicinity properties containing uranium mill tailings and related residual radioactive materials.

  11. Bioremediation of Uranium Plumes with Nano-scale

    E-Print Network [OSTI]

    Fay, Noah

    (IV) (UO2[s], uraninite) Anthropogenic · Release of mill tailings during uranium mining - MobilizationBioremediation of Uranium Plumes with Nano-scale Zero-valent Iron Angela Athey Advisers: Dr. Reyes Undergraduate Student Fellowship Program April 15, 2011 #12;Main Sources of Uranium Natural · Leaching from

  12. Composition of the U.S. DOE Depleted Uranium Inventory

    E-Print Network [OSTI]

    Concentration Of Less

    about 2.75 wt% U-235. For further enrichment, the material was shipped to the Oak Ridge and Portsmouth plants. In addition to natural uranium, also uranium recycled from spent fuel was fed into the Paducah enrichment cascade (Table 2 and Fig. 2). The recycled uranium introduced various isotopes not found in natural uranium into the cascade: fission products, such as Technetium-99; transuranics, such as Neptunium-237 and Plutonium-239; and the artificial uranium isotope of Uranium-236. The spent fuel, from which uranium was recycled, originated from the Hanford and Savannah River military plutonium production reactors. This uranium was recycled, although its assay of U-235 was somewhat lower than in natural uranium (Table 2). This obviously must be seen in the context of the Cold War era, when uranium was a scarce resource. Due to the low burn-up of the military reactors, concentrations of artificial U-236 are comparatively low in this recycled uranium. The recycled uranium represents

  13. Depleted uranium hexafluoride: Waste or resource?

    SciTech Connect (OSTI)

    Schwertz, N.; Zoller, J.; Rosen, R.; Patton, S. [Lawrence Livermore National Lab., CA (United States); Bradley, C. [USDOE Office of Nuclear Energy, Science, Technology, Washington, DC (United States); Murray, A. [SAIC (United States)

    1995-07-01T23:59:59.000Z

    the US Department of Energy is evaluating technologies for the storage, disposal, or re-use of depleted uranium hexafluoride (UF{sub 6}). This paper discusses the following options, and provides a technology assessment for each one: (1) conversion to UO{sub 2} for use as mixed oxide duel, (2) conversion to UO{sub 2} to make DUCRETE for a multi-purpose storage container, (3) conversion to depleted uranium metal for use as shielding, (4) conversion to uranium carbide for use as high-temperature gas-cooled reactor (HTGR) fuel. In addition, conversion to U{sub 3}O{sub 8} as an option for long-term storage is discussed.

  14. Depleted uranium plasma reduction system study

    SciTech Connect (OSTI)

    Rekemeyer, P.; Feizollahi, F.; Quapp, W.J.; Brown, B.W.

    1994-12-01T23:59:59.000Z

    A system life-cycle cost study was conducted of a preliminary design concept for a plasma reduction process for converting depleted uranium to uranium metal and anhydrous HF. The plasma-based process is expected to offer significant economic and environmental advantages over present technology. Depleted Uranium is currently stored in the form of solid UF{sub 6}, of which approximately 575,000 metric tons is stored at three locations in the U.S. The proposed system is preconceptual in nature, but includes all necessary processing equipment and facilities to perform the process. The study has identified total processing cost of approximately $3.00/kg of UF{sub 6} processed. Based on the results of this study, the development of a laboratory-scale system (1 kg/h throughput of UF6) is warranted. Further scaling of the process to pilot scale will be determined after laboratory testing is complete.

  15. Method for fluorination of uranium oxide

    DOE Patents [OSTI]

    Petit, George S. (Oak Ridge, TN)

    1987-01-01T23:59:59.000Z

    Highly pure uranium hexafluoride is made from uranium oxide and fluorine. The uranium oxide, which includes UO.sub.3, UO.sub.2, U.sub.3 O.sub.8 and mixtures thereof, is introduced together with a small amount of a fluorine-reactive substance, selected from alkali chlorides, silicon dioxide, silicic acid, ferric oxide, and bromine, into a constant volume reaction zone. Sufficient fluorine is charged into the zone at a temperature below approximately 0.degree. C. to provide an initial pressure of at least approximately 600 lbs/sq. in. at the ambient atmospheric temperature. The temperature is then allowed to rise in the reaction zone until reaction occurs.

  16. Corrosion behavior of technetium waste forms exposed to various aqueous environments

    SciTech Connect (OSTI)

    Kolman, David Gary [Los Alamos National Laboratory; Jarvinen, Gordon [Los Alamos National Laboratory; Mausolf, Edward [UNIV OF NEVADA; Czerwinski, Ken [UNIV OF NEVADA; Poineau, Frederic [UNIV OF NEVADA

    2009-01-01T23:59:59.000Z

    Technetium is a long-lived beta emitter produced in high yields from uranium as a waste product in spent nuclear fuel and has a high degree of environmental mobility as pertechnetate. It has been proposed that Tc be immobilized into various metallic waste forms to prevent Tc mobility while producing a material that can withstand corrosion exposed to various aqueous medias to prevent the leachability of Tc to the environment over long periods of time. This study investigates the corrosion behavior of Tc and Tc alloyed with 316 stainless steel and Zr exposed to a variety of aqueous media. To date, there is little investigative work related to Tc corrosion behavior and less related to potential Tc containing waste forms. Results indicate that immobilizing Tc into stainless steel-zirconium alloys can be a promising technique to store Tc for long periods of time while reducing the need to separately store used nuclear fuel cladding. Initial results indicate that metallic Tc and its alloys actively corrode in all media. We present preliminary corrosion rates of 100% Tc, 10% Tc - 90% SS{sub 85%}Zr{sub 15%}, and 2% Tc - 98% SS{sub 85%}Zr{sub 15%} in varying concentrations of nitric acid and pH 10 NaOH using the resistance polarization method while observing the trend that higher concentrations of Tc alloyed to the sample tested lowers the corrosion rate of the proposed waste package.

  17. Measurement of enriched uranium and uranium-aluminum fuel materials with the AWCC

    SciTech Connect (OSTI)

    Krick, M.S.; Menlove, H.O.; Zick, J.; Ikonomou, P.

    1985-05-01T23:59:59.000Z

    The active well coincidence counter (AWCC) was calibrated at the Chalk River Nuclear Laboratories (CRNL) for the assay of 93%-enriched fuel materials in three categories: (1) uranium-aluminum billets, (2) uranium-aluminum fuel elements, and (3) uranium metal pieces. The AWCC was a standard instrument supplied to the International Atomic Energy Agency under the International Safeguards Project Office Task A.51. Excellent agreement was obtained between the CRNL measurements and previous Los Alamos National Laboratory measurements on similar mockup fuel material. Calibration curves were obtained for each sample category. 2 refs., 8 figs., 15 tabs.

  18. ORNL/TM-2008/069 KENO-VI Primer: A Primer for

    E-Print Network [OSTI]

    Pennycook, Steve

    ORNL/TM-2008/069 KENO-VI Primer: A Primer for Criticality Calculations with SCALE/KENO-VI Using Gee Nuclear Information System (INIS) representatives from the following source. Office of Scientific or reflect those of the United States Government or any agency thereof. #12;ORNL/TM-2008/069 Nuclear Science

  19. Indledning Velkommen til Microsoft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Side 4 Inspiration Vi er drevet af passion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Side 8

    E-Print Network [OSTI]

    Hunt, Galen

    af software og it-løsninger . Siden 1990 har Microsoft været repræsenteret i Danmark, hvor vi i dag Danmark kombinerer det bedste fra to verdener: det ameri- kanske fokus på performance og talentudvikling,fleksibilitetogklaremålervoresDNA. Hos Microsoft Danmark er vi 450 medarbejdere med vidt forskellige baggrunde og kompetenc

  20. UMBC Policy on Facilities Use UMBC Policy # VI-4.10.01 1

    E-Print Network [OSTI]

    Adali, Tulay

    UMBC Policy on Facilities Use UMBC Policy # VI-4.10.01 1 I. Introduction This policy is predicated on the University System of Maryland Policy 145.0 VI-4.10- POLICY ON THE USE of Regents on January 11, 1990. The policy reads: 1. The physical facilities of the University System may

  1. U. S. forms uranium enrichment corporation

    SciTech Connect (OSTI)

    Seltzer, R.

    1993-07-12T23:59:59.000Z

    After almost 40 years of operation, the federal government is withdrawing from the uranium enrichment business. On July 1, the Department of Energy turned over to a new government-owned entity--the US Enrichment Corp. (USEC)--both the DOE enrichment plants at Paducah, Ky., and Portsmouth, Ohio, and domestic and international marketing of enriched uranium from them. Pushed by the inability of DOE's enrichment operations to meet foreign competition, Congress established USEC under the National Energy Policy Act of 1992, envisioning the new corporation as the first step to full privatization. With gross revenues of $1.5 billion in fiscal 1992, USEC would rank 275th on the Fortune 500 list of top US companies. USEC will lease from DOE the Paducah and Portsmouth facilities, built in the early 1950s, which use the gaseous diffusion process for uranium enrichment. USEC's stock is held by the US Treasury, to which it will pay annual dividends. Martin Marietta Energy Systems, which has operated Paducah since 1984 and Portsmouth since 1986 for DOE, will continue to operate both plants for USEC. Closing one of the two facilities will be studied, especially in light of a 40% world surplus of capacity over demand. USEC also will consider other nuclear-fuel-related ventures. USEC will produce only low-enriched uranium, not weapons-grade material. Indeed, USEC will implement a contract now being completed under which the US will purchase weapons-grade uranium from dismantled Russian nuclear weapons and convert it into low-enriched uranium for power reactor fuel.

  2. Floating plant can get uranium from seawater

    SciTech Connect (OSTI)

    Not Available

    1984-02-01T23:59:59.000Z

    A floating plant has been designed to extract uranium from seawater using solid adsorbents. Ore is removed from the adsorbent material by means of a solvent and concentrated in ion exchangers. Seawater is supplied to the adsorbent inside by wave energy and is based on the principle that waves will rush up a sloping plane that is partly submerged and fill a reservoir to a level higher than the still water level in the sea. The company projects that an offshore plant for recovering 600 tons of uranium/yr would comprise 22 floating concrete units, each measuring 430 x 75 meters.

  3. Decarburization of uranium via electron beam processing

    SciTech Connect (OSTI)

    McKoon, R H

    1998-10-23T23:59:59.000Z

    For many commercial and military applications, the successive Vacuum Induction Melting of uranium metal in graphite crucibles results in a product which is out of specification in carbon. The current recovery method involves dissolution of the metal in acid and chemical purification. This is both expensive and generates mixed waste. A study was undertaken at Lawrence Livermore National Laboratory to investigate the feasibility of reducing the carbon content of uranium metal using electron beam techniques. Results will be presented on the rate and extent of carbon removal as a function of various operating parameters.

  4. Progress toward uranium scrap recycling via EBCHR

    SciTech Connect (OSTI)

    McKoon, R.H.

    1994-11-01T23:59:59.000Z

    A 250 kW electron beam cold hearth refining (EBCHR) melt furnace at Lawrence Livermore National Laboratory (LLNL) has been in operation for over a year producing 5.5 in.-diameter ingots of various uranium alloys. Production of in-specification uranium-6%-niobium (U-6Nb) alloy ingots has been demonstrated using virgin feedstock. A vibratory scrap feeder has been installed on the system and the ability to recycle chopped U-6Nb scrap has been established. A preliminary comparison of vacuum arc remelted (VAR) and electron beam (EB) melted product is presented.

  5. Simulation of Reduction of Cr(VI) by Fe(II) Produced Electrochemically in a Parallel-Plate Electrochemical Reactor

    E-Print Network [OSTI]

    at the cathode, electrocoagulation uses electricity to produce a reducing agent ferrous ions from an iron anode the reduction of Cr VI by permeable reactive barriers. Gheju and Lovi7 reported that the re- duction of Cr VI

  6. Molecular Mechanisms of Uranium Reduction by Clostridia and its Manipulation

    SciTech Connect (OSTI)

    Matin, A. C.

    2006-06-01T23:59:59.000Z

    The objective of this grant is to examine and manipulate the molecular mechanisms in Clostridia to make them better agents for uranyl [U(VI)] bioremediation.

  7. Reduction and Reoxidation of Soils During and After Uranium Bioremediation; Implications for Long Term Uraninite Stability and Bioremediation Scheme Implementation

    SciTech Connect (OSTI)

    Peter R Jaffe

    2009-09-06T23:59:59.000Z

    The goal of this research was to study the reoxidation of biologically precipitated U(IV). Several experiments were performed and are summarized below. These experiments include: (1) a long-term (~200 days) U(VI) reduction experiment under low sulfate conditions in order to study in detail changes in iron phases and biomass and determine how they affect/buffer reoxidation; (2) a short term (~70 days) experiment where we tracked the uranium profile via XANES prior to reoxidation and during reoxidation in order to determine the U speciation; (3) a short term experiment where we compare the oxidation of U(IV) by oxygen and nitrate in the absence of FeS; and (4) a short term experiment where we compare the oxidation of U(IV) by oxygen and nitrate in the presence of FeS precipitates.

  8. Simplifying strong electronic correlations in uranium: Localized uranium heavy-fermion UM2Zn20 (M=Co,Rh) compounds

    E-Print Network [OSTI]

    Lawrence, Jon

    Simplifying strong electronic correlations in uranium: Localized uranium heavy-fermion UM2Zn20 (M Atómica, 8400 Bariloche, Argentina 6 Department of Chemistry and Biochemistry, University of Delaware-field effects corroborate an ionic-like uranium electronic configura- tion in UM2Zn20. DOI: 10.1103/PhysRevB.78

  9. STRUCTURE OF PENTAKIS (UREA) DIOXOURANIUM(VI)NITRATE LUO2 (OC (NH2)2)5 (NO3) 2

    E-Print Network [OSTI]

    Zalkin, Allan

    2011-01-01T23:59:59.000Z

    Chemistry University of California Berkeley, California 94720 AUGUST 1978 In our ongoing studies of uranium

  10. Integrated Ecogenomics Study for Bioremediation of Cr(VI) at Hanford 100H Area

    SciTech Connect (OSTI)

    Chakraborty, Romy; Chakraborty, Romy

    2008-08-12T23:59:59.000Z

    Hexavalent chromium is a widespread contaminant found in groundwater. In order to stimulate microbially mediated Cr(VI)-reduction, a poly-lactate compound was injected into Cr(VI)-contaminated aquifers at site 100H at Hanford. Investigation of bacterial community composition using high-density DNA microarray analysis of 16S rRNA gene products revealed a stimulation of Pseudomonas, Desulfovibrio and Geobacter species amongst others. Enrichment of these organisms coincided with continued Cr(VI) depletion. Functional gene-array analysis of DNA from monitoring well indicated high abundance of genes involved in nitrate-reduction, sulfate-reduction, iron-reduction, methanogenesis, chromium tolerance/reduction. Clone-library data revealed Psedomonas was the dominant genus in these samples. Based on above results, we conducted lab investigations to study the dominant anaerobic culturable microbial populations present at this site and their role in Cr(VI)-reduction. Enrichments using defined anaerobic media resulted in isolation of an iron-reducing, a sulfate-reducing and a nitrate-reducing isolate among several others. Preliminary 16S rDNA sequence analysis identified the isolates as Geobacter metallireducens, Pseudomonas stutzeri and Desulfovibrio vulgaris species respectively. The Pseudomonas isolate utilized acetate, lactate, glycerol and pyruvate as alternative carbon sources, and reduced Cr(VI). Anaerobic washed cell suspension of strain HLN reduced almost 95?M Cr(VI) within 4 hr. Further, with 100?M Cr(VI) as sole electron-acceptor, cells grew to 4.05 x 107 /ml over 24 h after an initial lag, demonstrating direct enzymatic Cr(VI) reduction coupled to growth. These results demonstrate that Cr(VI)-immobilization at Hanford 100H site could be mediated by direct microbial metabolism in addition to indirect chemical reduction of Cr(VI) by end-products of microbial activity.

  11. Recovery of uranium from seawater. 7; Concentration and separation of uranium in acidic eluate

    SciTech Connect (OSTI)

    Egawa, H.; Nonaka, T. (Dept. of Applied Chemistry, Faculty of Engineering, Kumamoto Univ., Kurokami 2-39-1, Kumamoto 860 (JP)); Nakayama, M. (Faculty of Pharmaceutical Sciences, Kumamoto Univ., Oe-Honmachi 5-1, Kumamoto 862 (JP))

    1990-11-01T23:59:59.000Z

    This paper reports on macroporous chelating resins (RSP, RSPO, RCSP, and RCSPO) containing dihydroxphosphino and/or -phosphono groups were examined for the concentration and separation of uranium from acidic eluates of macroporous chelating resin containing amidoxime groups. RSP and RSPO had a high adsorption capacity for uranium even in 0.25-0.50 mol {center dot} dm{sup {minus}3} H{sub 2}SO{sub 4}. Uranium adsorbed on the resins was eluted easily as a uranyl carbonate complex by use of 0.25 mol {center dot} dm{sup {minus}3} Na{sub 2}CO{sub 3}. In this effluent, other metal ions were hardly present. The use of RSP and RSPO was very effective in concentrating uranium from seawater and separating it from most other elements.

  12. Conversion and Blending Facility highly enriched uranium to low enriched uranium as metal. Revision 1

    SciTech Connect (OSTI)

    NONE

    1995-07-05T23:59:59.000Z

    The mission of this Conversion and Blending Facility (CBF) will be to blend surplus HEU metal and alloy with depleted uranium metal to produce an LEU product. The primary emphasis of this blending operation will be to destroy the weapons capability of large, surplus stockpiles of HEU. The blended LEU product can only be made weapons capable again by the uranium enrichment process. The blended LEU will be produced as a waste suitable for storage or disposal.

  13. Fision product evaluations for ENDF/B-VI

    SciTech Connect (OSTI)

    Wright, R.Q.

    1990-01-01T23:59:59.000Z

    Most of the ENDF/B-V fission-product evaluations were completed during the time period 1974--1980, and some of these were based on very limited experimental data. For short-lived fission products, there is still very little experimental data available because of the difficulty of obtaining these measurements. However, since 1980 a considerable amount of new experimental data have become available for stable and long-lived fission products. By utilizing the new data, significant improvements are now possible for some fission-product evaluations. The purpose of this paper is to report on 16 ENDF/B-VI evaluations that have been done at Oak Ridge National Laboratory (ORNL). The primary emphasis in this work has been placed on the resolved resonance region, but for some nuclides, new experimental data were also used to improve the evaluations for energies above the resolved resonance range.

  14. Extraction of uranium from seawater using magnetic adsorbents

    SciTech Connect (OSTI)

    Yamashita, H. (Hitachi Research Lab., Japan); Fujita, K.; Nakajima, F.; Ozawa, Y.; Murata, T.

    1981-01-01T23:59:59.000Z

    A new process for the extraction of uranium from seawater was developed. In the process, uranium adsorption is effected using powdered magnetic adsorbents; the adsorbents are then separated from seawater using magnetic separation technology. This process is superior to a column method using a granulated hydrous titanium oxide adsorber bed in the following ways: (1) a higher rate of adsorption is realized because smaller particles are used in the uranium adsorption; and (2) blocking, which is inevitable in an adsorber bed, is eliminated. The composite hydrous titanium-iron oxide as a magnetic adsorbent having high uranium adsorption capacity and magnetization can be prepared by adding urea to a mixed solution of titanium sulfate and ferrous sulfate. Adsorption and desoprtion of uranium and the removal of the adsorbent using a small-scale uranium extraction plant (about 15 m/sup 3//d) is reported, and the feasibility of uranium extraction from seawater by this process is demonstrated. 10 figures.

  15. New aspects of uranium recovery from seawater

    SciTech Connect (OSTI)

    Hetkamp, D.; Wagener, K.

    1982-10-01T23:59:59.000Z

    The properties of various adsorbents for uranium extraction from seawater are measured under standardized experimental conditions. It turns out that fractionated humic acids have exceptionally fast loading kinetics. This property leads to a substantial reduction of capital investments in conventional adsorbent bed techniques as well as in a procedure designed to avoid large adsorbent bed constructions by using carrier bodies in the open sea.

  16. Phosphate Barriers for Immobilization of Uranium Plumes

    SciTech Connect (OSTI)

    Burns, Peter C.

    2004-12-01T23:59:59.000Z

    Uranium contamination of the subsurface remains a persistent problem plaguing remedial design at sites across the U.S. that were involved with production, handling, storage, milling, and reprocessing of uranium for both civilian and defense related purposes. Remediation efforts to date have relied upon excavation, pump-and-treat, or passive remediation barriers (PRB?s) to remove or attenuate uranium mobility. Documented cases convincingly demonstrate that excavation and pump-and-treat methods are ineffective for a number of highly contaminated sites. There is growing concern that use of conventional PRB?s, such as zero-valent iron, may be a temporary solution to a problem that will persist for thousands of years. Alternatives to the standard treatment methods are therefore warranted. The core objective of our research is to demonstrate that a phosphorus amendment strategy will result in a reduction of dissolved uranium to below the proposed drinking water standard. Our hypothesis is that long-chain sodium polyphosphate compounds forestall precipitation of sparingly soluble uranyl phosphate compounds, which is paramount to preventing fouling of wells at the point of injection.

  17. The Uranium Institute 24th Annual Symposium

    E-Print Network [OSTI]

    Laughlin, Robert B.

    -239 for use in subsequent reactors. A fast neutron reactor is capable of producing more plutonium fuel than the uranium fuel it burns, leading to a breeder reactor. In addition, if the reactor is a fast with half lives of 30 years or less. The fast neutron reactor of preference was to be cooled with liquid

  18. The multiphoton ionization of uranium hexafluoride

    SciTech Connect (OSTI)

    Armstrong, D.P. (Oak Ridge K-25 Site, TN (United States). UEO Enrichment Technical Operations Div.)

    1992-05-01T23:59:59.000Z

    Multiphoton ionization (MPI) time-of-flight mass spectroscopy and photoelectron spectroscopy studies of UF{sub 6} have been conducted using focused light from the Nd:YAG laser fundamental ({lambda}=1064 nm) and its harmonics ({lambda}=532, 355, or 266 nm), as well as other wavelengths provided by a tunable dye laser. The MPI mass spectra are dominated by the singly and multiply charged uranium ions rather than by the UF{sub x}{sup +} fragment ions even at the lowest laser power densities at which signal could be detected. The laser power dependence of U{sup n+} ions signals indicates that saturation can occur for many of the steps required for their ionization. In general, the doubly-charged uranium ion (U{sup 2+}) intensity is much greater than that of the singly-charged uranium ion (U{sup +}). For the case of the tunable dye laser experiments, the U{sup n+} (n = 1- 4) wavelength dependence is relatively unstructured and does not show observable resonance enhancement at known atomic uranium excitation wavelengths. The dominance of the U{sup 2+} ion and the absence or very small intensities of UF{sub x}{sup +} fragments, along with the unsaturated wavelength dependence, indicate that mechanisms may exist other than ionization of bare U atoms after the stepwise photodissociation of F atoms from the parent molecule.

  19. The Quest for the Heaviest Uranium Isotope

    E-Print Network [OSTI]

    S. Schramm; D. Gridnev; D. V. Tarasov; V. N. Tarasov; W. Greiner

    2012-01-17T23:59:59.000Z

    We study Uranium isotopes and surrounding elements at very large neutron number excess. Relativistic mean field and Skyrme-type approaches with different parametrizations are used in the study. Most models show clear indications for isotopes that are stable with respect to neutron emission far beyond N=184 up to the range of around N=258.

  20. Geodatabase of the South Texas Uranium District

    E-Print Network [OSTI]

    Mark Beaman; William Wade Mcgee

    Uranium and its associated trace elements and radionuclides are ubiquitous in the South Texas Tertiary environment. Surface mining of this resource from the 1960s through the early 1980s at over sixty locations has left an extensive anthropological footprint (Fig. 1) in the lower Nueces and San Antonio river basins. Reclamation of mining initiated after 1975 has been under the regulatory authority of the Railroad Commission of Texas (RCT). However, mines that were active before the Texas Surface Mining Act of 1975 was enacted, and never reclaimed, are now considered abandoned. The Abandoned Mine Land Section of the RCT is currently reclaiming these pre-regulation uranium mines with funding from the federal government. The RCT monitors the overall effectiveness of this process through post-reclamation radiation and vegetative cover surveys, water quality testing, slope stability and erosion control monitoring. Presently a number of graduate and postgraduate students are completing research on the watershed and reservoir distribution of trace elements and radionuclides downstream of the South Texas Uranium District. The question remains as to whether the elevated levels of uranium, its associated trace elements and radiation levels in the South Texas environment are due to mining

  1. Standard test method for determination of uranium or gadolinium (or both) in gadolinium oxide-uranium oxide pellets or by X-ray fluorescence (XRF)

    E-Print Network [OSTI]

    American Society for Testing and Materials. Philadelphia

    2008-01-01T23:59:59.000Z

    Standard test method for determination of uranium or gadolinium (or both) in gadolinium oxide-uranium oxide pellets or by X-ray fluorescence (XRF)

  2. Control of structure and reactivity by ligand design : applications to small molecule activation by low-valent uranium complexes

    E-Print Network [OSTI]

    Lam, Oanh Phi

    2010-01-01T23:59:59.000Z

    researchers from uranium chemistry. Fortunately, despitescarce in uranium coordination chemistry. A more detailedligands for uranium coordination chemistry. Figure 4-2.

  3. Reduction of Fe(III), Cr(VI), U(VI), and Tc(VII) by Deinococcus radiodurans R1

    SciTech Connect (OSTI)

    Fredrickson, J.K.; Kostandarithes, H.M.; Li, S.W.; Plymake, A.E.; Daly, M.J.

    2000-05-01T23:59:59.000Z

    Deinococcus radiodurans is an exceptionally radiation-resistant microorganism capable of surviving acute exposures to ionizing radiation doses of 15,000 Gy and previously described as having a strictly aerobic respiratory metabolism. Under strict anaerobic conditions, D. radiodurans R1 reduced Fe(III)-nitrilotriacetic acid coupled to the oxidation of lactate to CO{sub 2} and acetate but was unable to link this process to growth. D. radiodurans reduced the humic acid analog anthraquinone-2,6-disulfonate (AQDS) to its dihydroquinone form, AH{sub 2}DS, which subsequently transferred electrons to the Fe(III) oxides hydrous ferric oxide and goethite via a previously described electron shuttle mechanism. D. radiodurans reduced the solid-phase Fe(III) oxides in the presence of either 0.1 mM AQDS or leonardite humic acids (2 mg ml{sup {minus}1}) but not in their absence. D. radiodurans also reduced U(VI) and Tc(VII) in the presence of AQDS. In contrast, Cr(VI) was directly reduced in anaerobic cultures with lactate although the rate of reduction was higher in the presence of AQDS. The results are the first evidence that D. radiodurans can reduce Fe(III) coupled to the oxidation of lactate or other organic compounds. Also, D. radiodurans, in combination with humic acids or synthetic electron shuttle agents, can reduce U and Tc and thus has potential applications for remediation of metal- and radionuclide-contaminated sites where ionizing radiation or other DNA-damaging agents may restrict the activity of more sensitive organisms.

  4. Chemical Equilibrium of the Dissolved Uranium in Groundwaters From a Spanish Uranium-Ore Deposit

    SciTech Connect (OSTI)

    Garralon, Antonio; Gomez, Paloma; Turrero, Maria Jesus; Buil, Belen; Sanchez, Lorenzo [Departamento de Medio Ambiente, CIEMAT, Avda. Complutense 22. Edificio 19, Madrid, 28040 (Spain)

    2007-07-01T23:59:59.000Z

    The main objectives of this work are to determine the hydrogeochemical evolution of an uranium ore and identify the main water/rock interaction processes that control the dissolved uranium content. The Mina Fe uranium-ore deposit is the most important and biggest mine worked in Spain. Sageras area is located at the north part of the Mina Fe, over the same ore deposit. The uranium deposit was not mined in Sageras and was only perturbed by the exploration activities performed 20 years ago. The studied area is located 10 Km northeast of Ciudad Rodrigo (Salamanca) at an altitude over 650 m.a.s.l. The uranium mineralization is related to faults affecting the metasediments of the Upper Proterozoic to Lower Cambrian schist-graywacke complex (CEG), located in the Centro-Iberian Zone of the Hesperian Massif . The primary uranium minerals are uraninite and coffinite but numerous secondary uranium minerals have been formed as a result of the weathering processes: yellow gummite, autunite, meta-autunite, torbernite, saleeite, uranotile, ianthinite and uranopilite. The water flow at regional scale is controlled by the topography. Recharge takes place mainly in the surrounding mountains (Sierra Pena de Francia) and discharge at fluvial courses, mainly Agueda and Yeltes rivers, boundaries S-NW and NE of the area, respectively. Deep flows (lower than 100 m depth) should be upwards due to the river vicinity, with flow directions towards the W, NW or N. In Sageras-Mina Fe there are more than 100 boreholes drilled to investigate the mineral resources of the deposit. 35 boreholes were selected in order to analyze the chemical composition of groundwaters based on their depth and situation around the uranium ore. Groundwater samples come from 50 to 150 m depth. The waters are classified as calcium-bicarbonate type waters, with a redox potential that indicates they are slightly reduced (values vary between 50 to -350 mV). The TOC varies between <0.1 and 4.0 mgC/L and the dissolved uranium has a maximum value of 7.7 mg/L. According the analytical data of dissolved uranium, the mineral closest to equilibrium seems to be UO{sub 2}(am). The tritium contents in the groundwaters vary between 1.5 and 7.3 T.U. Considering that the mean value of tritium in rainwater from the studied area has a value of 4 T.U., it can be concluded that the residence times of the groundwaters are relatively short, not longer than 50 years in the oldest case. (authors)

  5. Baseline risk assessment of groundwater contamination at the uranium mill tailings site near Shiprock, New Mexico. Draft

    SciTech Connect (OSTI)

    Not Available

    1993-09-01T23:59:59.000Z

    This report evaluates potential impact to public health or the environment resulting from groundwater contamination at the former uranium mill processing site. The tailings and other contaminated material at this site were placed in a disposal cell on the site in 1986 by the US Department of Energy`s (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. Currently, the UMTRA Project is evaluating groundwater contamination. This risk assessment is the first document specific to this site for the Groundwater Project. This risk assessment follows the approach outlined by the US Environmental Protection Agency (EPA). The first step is to evaluate groundwater data collected from monitor wells at the site. Evaluation of these data showed that the main contaminants in the floodplain groundwater are arsenic, magnesium, manganese, nitrate, sodium, sulfate, and uranium. The complete list of contaminants associated with the terrace groundwater could not be determined due to the lack of the background groundwater quality data. However, uranium, nitrate, and sulfate are evaluated since these chemicals are clearly associated with uranium processing and are highly elevated compared to regional waters. It also could not be determined if the groundwater occurring in the terrace is a usable water resource, since it appears to have originated largely from past milling operations. The next step in the risk assessment is to estimate how much of these contaminants people would be exposed to if a drinking well were installed in the contaminated groundwater or if there were exposure to surface expressions of contaminated water. Potential exposures to surface water include incidental contact with contaminated water or sediments by children playing on the floodplain and consumption of meat and milk from domestic animals grazed and watered on the floodplain.

  6. The galvanic corrosion behavior of depleted uranium in synthetic seawater coupled to aluminum, magnesium, and mild steel

    SciTech Connect (OSTI)

    McIntyre, J.F.; LeFeave, E.P.; Musselman, K.A.

    1987-01-01T23:59:59.000Z

    The galvanic corrosion behavior of a depleted uranium-titanium alloy (Du-.75Ti) coupled to MgZk60A-T5, AA-7075-T6, bare steel-4340, and coated steel-4340 exposed to ASTM seawater was investigated by monitoring the galvanic current with time. Gravimetric measurements, polarization resistance measurements, and concepts of ''mixed-potential'' theory were used to calculate corrosion rates. It was demonstrated that galvanic currents must be monitored over extended periods of time to detect changes in the galvanic corrosion behavior. Good agreement was obtained for corrosion rates calculated using the concepts of ''mixed-potential'' theory and those obtained from gravimetric measurements.

  7. Elucidating Bioreductive Transformations within Physically Complex Media: Impact on the Fate and Transport of Uranium and Chromium

    SciTech Connect (OSTI)

    Fendorf, Scott; Francis, Chris; Benner, Shawn; Jardine, Phil

    2006-11-01T23:59:59.000Z

    Uranium and chromium are two elements of particular concern within the DOE complex that, owing to their abundance and toxicity, appear well suited for biologically mediated reductive stabilization. Subsurface microbial activity can alter the redox state of toxic metals and radionuclides, rending them immobile. Furthermore, anaerobic bacterial metabolic products will help to buffer pulses of oxidation, typically from fluxes of nitrate or molecular oxygen, and thus may stabilize reduced contaminants from oxidative mobilization. Imparting an important criterion on the probability that contaminants will undergo reductive stabilization, however, is the physical nature along with the chemical and physical heterogeneity of the media. In our study we have been investigating the impact of chemical/mineralogical heterogeneity on uranium reduction, with an emphasis on iron transformations and resulting impacts on contaminant retention. We have, in particular, emphasized considering chemical/mineralogical and physical complexity on bioreduction of metals. Over the past year we have also made appreciable advances on discerning geochemical constraints on microbially mediated reduction of U(VI) and on means to discern spatial heterogeneity in operative biogeochemical reactions within soils and sediments.

  8. Subsurface microbial community structure correlates with uranium redox phases during in situ field manipulation in a contaminated aquifer

    SciTech Connect (OSTI)

    Kostka, Joel [Florida State University; Green, Stefan [Florida State University, Tallahassee; Wu, Wei-min [Stanford University; Criddle, Craig [Stanford University; Watson, David B [ORNL; Jardine, Philip M [ORNL

    2009-07-01T23:59:59.000Z

    Long-term field manipulation experiments investigating the effects of subsurface redox conditions on the fate and transport of soluble uranium(VI) were conducted over a 3 year period at the Oak Ridge Integrated Field Research Center (OR-IFRC) in Oak Ridge, TN. In the highly contaminated source zone, introduction of ethanol to the subsurface stimulated native denitrifying, sulfate-reducing, iron-reducing and fermentative microorganisms and reduced U to below 0.03 mg/L. Subsequently, oxygen and nitrate were experimentally re-introduced into the subsurface to examine the potential for re-oxidation and re-mobilization of U(IV). Introduction of oxygen or nitrate caused changes in subsurface geochemistry and re-oxidation of U. After reoxidation, the subsurface experienced several months of starvation conditions before ethanol injection was restored to reduce the treatment zone. Subsurface microorganisms were characterized by community fingerprinting, targeted population analyses, and quantitative PCR of key functional groups in 50 samples taken during multiple phases of field manipulation. Statistical analysis confirmed the hypothesis that the microbial community would co-vary with the shifts in the subsurface geochemistry. The level of hydraulic connectivity of sampling wells to the injection well was readily tracked by microbial community analysis. We demonstrate quantitatively that specific populations, especially Desulfosporosinus, are heavily influenced by geochemical conditions and positively correlate with the immobilization of uranium. Following nitrate reoxidation, populations of Fe(II)-oxidizing, nitrate reducing organisms (Thiobacillus) showed an increase in relative abundance.

  9. Use of a permeable biological reaction barrier for groundwater remediation at a uranium mill tailings remedial action (UMTRA) site

    SciTech Connect (OSTI)

    Thombre, M.S.; Thomson, B.M.; Barton, L.L. [Univ. of New Mexico, Albuquerque, NM (United States)

    1997-12-31T23:59:59.000Z

    Previous work at the University of New Mexico and elsewhere has shown that sulfate reducing bacteria are capable of reducing uranium from the soluble +6 oxidation state to the insoluble +4 oxidation state. This chemistry forms the basis of a proposed groundwater remediation strategy in which microbial reduction would be used to immobilize soluble uranium. One such system would consist of a subsurface permeable barrier which would stimulate microbial growth resulting in the reduction of sulfate and nitrate and immobilization of metals while permitting the unhindered flow of ground water through it. This research investigated some of the engineering considerations associated with a microbial reducing barrier such as identifying an appropriate biological substrate, estimating the rate of substrate utilization, and identifying the final fate of the contaminants concentrated in the barrier matrix. The performance of batch reactors and column systems that treated simulated plume water was evaluated using cellulose, wheat straw, alfalfa hay, sawdust, and soluble starch as substrates. The concentrations of sulfate, nitrate, and U(VI) were monitored over time. Precipitates from each system were collected and the precipitated U(IV) was determined to be crystalline UO{sub 2}(s) by X-ray Diffraction. The results of this study support the proposed use of cellulosic substrates as candidate barrier materials.

  10. Assessing the environmental availability of uranium in soils and sediments

    SciTech Connect (OSTI)

    Amonette, J.E.; Holdren, G.R. Jr.; Krupa, K.M.; Lindenmeier, C.W. [Pacific Northwest Lab., Richland, WA (United States)

    1994-06-01T23:59:59.000Z

    Soils and sediments contaminated with uranium pose certain environmental and ecological risks. At low to moderate levels of contamination, the magnitude of these risks depends not only on the absolute concentrations of uranium in the material but also on the availability of the uranium to drinking water supplies, plants, or higher organisms. Rational approaches for regulating the clean-up of sites contaminated with uranium, therefore, should consider the value of assessing the environmental availability of uranium at the site before making decisions regarding remediation. The purpose of this work is to review existing approaches and procedures to determine their potential applicability for assessing the environmental availability of uranium in bulk soils or sediments. In addition to making the recommendations regarding methodology, the authors have tabulated data from the literature on the aqueous complexes of uranium and major uranium minerals, examined the possibility of predicting environmental availability of uranium based on thermodynamic solubility data, and compiled a representative list of analytical laboratories capable of performing environmental analyses of uranium in soils and sediments.

  11. Reduction of U(VI) Complexes by Anthraquinone Disulfonate: Experiment and Molecular Modeling

    SciTech Connect (OSTI)

    Ainsworth, C.C.; Wang, Z.; Rosso, K.M.; Wagnon, K.; Fredrickson, J.K.

    2004-03-17T23:59:59.000Z

    Past studies demonstrate that complexation will limit abiotic and biotic U(VI) reduction rates and the overall extent of reduction. However, the underlying basis for this behavior is not understood and presently unpredictable across species and ligand structure. The central tenets of these investigations are: (1) reduction of U(VI) follows the electron-transfer (ET) mechanism developed by Marcus; (2) the ET rate is the rate-limiting step in U(VI) reduction and is the step that is most affected by complexation; and (3) Marcus theory can be used to unify the apparently disparate U(VI) reduction rate data and as a computational tool to construct a predictive relationship.

  12. E-Print Network 3.0 - alfa survey vi Sample Search Results

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Paris VI pastel-00636920,version1-28Oct2011 12;11 elaboration of nitrogen-doped aerogels and xerogels Source: Paris-Sud XI, Universit de - Institut d'Optique, Laboratoire...

  13. U(VI) sorption and reduction kinetics on the magnetite (111)...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    information in real-time under batch-flow conditions. Citation: Singer DM, SME Chatman, ES Ilton, KM Rosso, JF Banfield, and G Waychunas.2012."U(VI) sorption and...

  14. Cr(VI) reduction in aqueous solutions by using copper smelter slag

    SciTech Connect (OSTI)

    Kiyak, B.; Oezer, A.; Altundogan, H.S.; Erdem, M.; Tuemen, F. (Firat Univ., Elazig (Turkey))

    1999-01-01T23:59:59.000Z

    The ability of Copper Smelter Slag (CSS) to reduce Cr(VI) in aqueous solutions has been investigated. The extent of reduction if dependent on the amounts of acid and reductant, contact time, Cr(VI) concentration, temperature of the solution and particle size of CSS. The amount of acid is the most important variable affecting the reduction process. When twice the amount of acid required with respect to Cr(VI) was used, Cr(VI) in 100 ml solution (100 mg/l) was completely reduced in a contact period less than 5 min by a 10 g/l dosage of CSS. Reduction efficiency increased with increase in temperature of solution, showing that the process is endothermic. Reduced chromium, and iron and other metals dissolved from CSS were effectively precipitated by using NaOH or calcinated carbonation sludge from sugar plant.

  15. Cr(VI) reduction in aqueous solutions by using copper smelter slag

    SciTech Connect (OSTI)

    Kiyak, B.; Oezer, A.; Altundogan, H.S.; Erdem, M.; Tuemen, F. [Firat Univ., Elazig (Turkey)] [Firat Univ., Elazig (Turkey)

    1999-11-01T23:59:59.000Z

    The ability of Copper Smelter Slag (CSS) to reduce Cr(VI) in aqueous solutions has been investigated. The extent of reduction if dependent on the amounts of acid and reductant, contact time, Cr(VI) concentration, temperature of the solution and particle size of CSS. The amount of acid is the most important variable affecting the reduction process. When twice the amount of acid required with respect to Cr(VI) was used, Cr(VI) in 100 ml solution (100 mg/l) was completely reduced in a contact period less than 5 min by a 10 g/l dosage of CSS. Reduction efficiency increased with increase in temperature of solution, showing that the process is endothermic. Reduced chromium, and iron and other metals dissolved from CSS were effectively precipitated by using NaOH or calcinated carbonation sludge from sugar plant.

  16. Reduction of Health Risks Due to Chromium(VI)Using Mesquite: A Potential Cr Phytoremediator

    SciTech Connect (OSTI)

    Gardea-Torresdey, Jorge L.; Aldrich, Mary V.; Peralta-Videa, Jose R.; Parsons, Jason G.

    2004-03-29T23:59:59.000Z

    Chromium is a transition metal extensively used in industry. Cr mining and industrial operations account for chromium wastes at Superfund sites in the United States. A study was performed to investigate the possibility of using mesquite (Prosopis spp.), which is an indigenous desert plant species, to remove Cr from contaminated sites. In this study, mesquite plants were grown in an agar-based medium containing 75 mg L-1 and 125 mg L-1 of Cr(VI). The Cr content of leaf tissue (992 mg kg-1 of dry weight, from 125 mg L-1 of Cr(VI)) indicated that mesquite could be classified as a chromium hyperaccumulator. X-ray absorption spectroscopy (XAS) studies performed to experimental samples showed that mesquite roots absorbed some of the supplied Cr(VI). However, the data analyses of plant tissues demonstrated that the absorbed Cr(VI) was fully reduced to Cr(III) in the leaf tissue.

  17. Microsoft Word - ViArray_Fact_ Sheet_SAND2011-3935P_updated_format...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ng ViASIC(tm) e circuits tha operations. power and g n high-reliab D Category 1 plined ISO 9 al, analog an bility, Sandia national secu d ASIC grated Circui ASIC-like p (NRE)...

  18. A method to attenuate U(VI) mobility in acidic waste plumes using humic acids

    E-Print Network [OSTI]

    Wan, J.

    2011-01-01T23:59:59.000Z

    base properties of a goethite surface model: A theoreticalcomplexation of U(VI) on goethite (alpha-FeOOH). Geochim.acid and humic-acid on goethite, gibbsite and imogolite. J.

  19. Regulation of Myosin VI transport, tethering to actin and cargo binding

    E-Print Network [OSTI]

    Naccache, Samia Nidal

    2006-01-01T23:59:59.000Z

    M. Walker, J. Trinick, F. Buss, C. Veigel and J. Kendrick-J. Kendrick-Jones and F. Buss (2005). "Optineurin linksJ. Kendrick-Jones and F. Buss (2003). "Loss of myosin VI

  20. The uranium cylinder assay system for enrichment plant safeguards

    SciTech Connect (OSTI)

    Miller, Karen A [Los Alamos National Laboratory; Swinhoe, Martyn T [Los Alamos National Laboratory; Marlow, Johnna B [Los Alamos National Laboratory; Menlove, Howard O [Los Alamos National Laboratory; Rael, Carlos D [Los Alamos National Laboratory; Iwamoto, Tomonori [JNFL; Tamura, Takayuki [JNFL; Aiuchi, Syun [JNFL

    2010-01-01T23:59:59.000Z

    Safeguarding sensitive fuel cycle technology such as uranium enrichment is a critical component in preventing the spread of nuclear weapons. A useful tool for the nuclear materials accountancy of such a plant would be an instrument that measured the uranium content of UF{sub 6} cylinders. The Uranium Cylinder Assay System (UCAS) was designed for Japan Nuclear Fuel Limited (JNFL) for use in the Rokkasho Enrichment Plant in Japan for this purpose. It uses total neutron counting to determine uranium mass in UF{sub 6} cylinders given a known enrichment. This paper describes the design of UCAS, which includes features to allow for unattended operation. It can be used on 30B and 48Y cylinders to measure depleted, natural, and enriched uranium. It can also be used to assess the amount of uranium in decommissioned equipment and waste containers. Experimental measurements have been carried out in the laboratory and these are in good agreement with the Monte Carlo modeling results.

  1. Recovery of uranium from seawater by immobilized tannin

    SciTech Connect (OSTI)

    Sakaguchi, T.; Nakajima, A.

    1987-06-01T23:59:59.000Z

    Tannin compounds having multiple adjacent hydroxy groups have an extremely high affinity for uranium. To prevent the leaching of tannins into water and to improve the adsorbing characteristics of these compounds, the authors tried to immobilize tannins. The immobilized tannin has the most favorable features for uranium recovery; high selective adsorption ability to uranium, rapid adsorption rate, and applicability in both column and batch systems. The immobilized tannin can recover uranium from natural seawater with high efficiency. About 2530 ..mu..g uranium is adsorbed per gram of this adsorbent within 22 h. Depending on the concentration in seawater, an enrichment of up to 766,000-fold within the adsorbent is possible. Almost all uranium adsorbed is easily desorbed with a very dilute acid. Thus, the immobilized tannin can be used repeatedly in the adsorption-desorption process.

  2. In-line assay monitor for uranium hexafluoride

    DOE Patents [OSTI]

    Wallace, S.A.

    1980-03-21T23:59:59.000Z

    An in-line assay monitor for determining the content of uranium-235 in a uranium hexafluoride gas isotopic separation system is provided which removes the necessity of complete access to the operating parameters of the system for determining the uranium-235 content. The method and monitor for carrying out the method involve cooling of a radiation pervious chamber connected in fluid communication with the selected point in the system to withdraw a specimen and solidify the specimen in the chamber. The specimen is irradiated by means of an ionizing radiation source of energy different from that of the 185 keV gamma emissions from uranium-235. The uranium-235 content of the specimen is determined from comparison of the accumulated 185 keV energy counts and reference energy counts. The latter is used to measure the total uranium isotopic content of the specimen.

  3. Assessment of Preferred Depleted Uranium Disposal Forms

    SciTech Connect (OSTI)

    Croff, A.G.; Hightower, J.R.; Lee, D.W.; Michaels, G.E.; Ranek, N.L.; Trabalka, J.R.

    2000-06-01T23:59:59.000Z

    The Department of Energy (DOE) is in the process of converting about 700,000 metric tons (MT) of depleted uranium hexafluoride (DUF6) containing 475,000 MT of depleted uranium (DU) to a stable form more suitable for long-term storage or disposal. Potential conversion forms include the tetrafluoride (DUF4), oxide (DUO2 or DU3O8), or metal. If worthwhile beneficial uses cannot be found for the DU product form, it will be sent to an appropriate site for disposal. The DU products are considered to be low-level waste (LLW) under both DOE orders and Nuclear Regulatory Commission (NRC) regulations. The objective of this study was to assess the acceptability of the potential DU conversion products at potential LLW disposal sites to provide a basis for DOE decisions on the preferred DU product form and a path forward that will ensure reliable and efficient disposal.

  4. Uranium Oxide Aerosol Transport in Porous Graphite

    SciTech Connect (OSTI)

    Blanchard, Jeremy; Gerlach, David C.; Scheele, Randall D.; Stewart, Mark L.; Reid, Bruce D.; Gauglitz, Phillip A.; Bagaasen, Larry M.; Brown, Charles C.; Iovin, Cristian; Delegard, Calvin H.; Zelenyuk, Alla; Buck, Edgar C.; Riley, Brian J.; Burns, Carolyn A.

    2012-01-23T23:59:59.000Z

    The objective of this paper is to investigate the transport of uranium oxide particles that may be present in carbon dioxide (CO2) gas coolant, into the graphite blocks of gas-cooled, graphite moderated reactors. The transport of uranium oxide in the coolant system, and subsequent deposition of this material in the graphite, of such reactors is of interest because it has the potential to influence the application of the Graphite Isotope Ratio Method (GIRM). The GIRM is a technology that has been developed to validate the declared operation of graphite moderated reactors. GIRM exploits isotopic ratio changes that occur in the impurity elements present in the graphite to infer cumulative exposure and hence the reactor’s lifetime cumulative plutonium production. Reference Gesh, et. al., for a more complete discussion on the GIRM technology.

  5. Uranium enrichment export control guide: Gaseous diffusion

    SciTech Connect (OSTI)

    Not Available

    1989-09-01T23:59:59.000Z

    This document was prepared to serve as a guide for export control officials in their interpretation, understanding, and implementation of export laws that relate to the Zangger International Trigger List for gaseous diffusion uranium enrichment process components, equipment, and materials. Particular emphasis is focused on items that are especially designed or prepared since export controls are required for these by States that are party to the International Nuclear Nonproliferation Treaty.

  6. Energy balance for uranium recovery from seawater

    SciTech Connect (OSTI)

    Schneider, E.; Lindner, H. [The University of Texas, 1 University Station C2200, Austin, TX 78712 (United States)

    2013-07-01T23:59:59.000Z

    The energy return on investment (EROI) of an energy resource is the ratio of the energy it ultimately produces to the energy used to recover it. EROI is a key viability measure for a new recovery technology, particularly in its early stages of development when financial cost assessment would be premature or highly uncertain. This paper estimates the EROI of uranium recovery from seawater via a braid adsorbent technology. In this paper, the energy cost of obtaining uranium from seawater is assessed by breaking the production chain into three processes: adsorbent production, adsorbent deployment and mooring, and uranium elution and purification. Both direct and embodied energy inputs are considered. Direct energy is the energy used by the processes themselves, while embodied energy is used to fabricate their material, equipment or chemical inputs. If the uranium is used in a once-through fuel cycle, the braid adsorbent technology EROI ranges from 12 to 27, depending on still-uncertain performance and system design parameters. It is highly sensitive to the adsorbent capacity in grams of U captured per kg of adsorbent as well as to potential economies in chemical use. This compares to an EROI of ca. 300 for contemporary terrestrial mining. It is important to note that these figures only consider the mineral extraction step in the fuel cycle. At a reference performance level of 2.76 g U recovered per kg adsorbent immersed, the largest energy consumers are the chemicals used in adsorbent production (63%), anchor chain mooring system fabrication and operations (17%), and unit processes in the adsorbent production step (12%). (authors)

  7. Uranium recovery from seawater by adsorption

    SciTech Connect (OSTI)

    Koske, P.H.; Ohlrogge, K.; Peinemann, K.V.

    1988-10-01T23:59:59.000Z

    Results are presented of a 10 weeks field experiment producing uranium from seawater by the so-called adsorber-loop-concept. For the adsorption process polyamidoxin (PAO) granulate has been used with grain sizes between 0.3 - 1.2 mm diameter. The performance of the adsorber and the efficiency of the adsorption process - especially with regard to high volume flows of seawater - are presented.

  8. The ultimate disposition of depleted uranium

    SciTech Connect (OSTI)

    Not Available

    1990-12-01T23:59:59.000Z

    Significant amounts of the depleted uranium (DU) created by past uranium enrichment activities have been sold, disposed of commercially, or utilized by defense programs. In recent years, however, the demand for DU has become quite small compared to quantities available, and within the US Department of Energy (DOE) there is concern for any risks and/or cost liabilities that might be associated with the ever-growing inventory of this material. As a result, Martin Marietta Energy Systems, Inc. (Energy Systems), was asked to review options and to develop a comprehensive plan for inventory management and the ultimate disposition of DU accumulated at the gaseous diffusion plants (GDPs). An Energy Systems task team, under the chairmanship of T. R. Lemons, was formed in late 1989 to provide advice and guidance for this task. This report reviews options and recommends actions and objectives in the management of working inventories of partially depleted feed (PDF) materials and for the ultimate disposition of fully depleted uranium (FDU). Actions that should be considered are as follows. (1) Inspect UF{sub 6} cylinders on a semiannual basis. (2) Upgrade cylinder maintenance and storage yards. (3) Convert FDU to U{sub 3}O{sub 8} for long-term storage or disposal. This will include provisions for partial recovery of costs to offset those associated with DU inventory management and the ultimate disposal of FDU. Another recommendation is to drop the term tails'' in favor of depleted uranium'' or DU'' because the tails'' label implies that it is waste.'' 13 refs.

  9. Phosphate Barriers for Immobilization of Uranium Plumes

    SciTech Connect (OSTI)

    Burns, Peter C.

    2005-06-01T23:59:59.000Z

    Uranium contamination of the subsurface has remained a persistent problem plaguing remedial design at sites across the U.S. that were involved with production, handling, storage, milling, and reprocessing of fissile uranium for both civilian and defense related purposes. Remediation efforts to date have relied upon excavation, pump-and-treat, or passive remediation barriers (PRB?s) to remove or attenuate uranium mobility. Documented cases convincingly demonstrate that excavation and pump-and-treat methods are ineffective for a number of highly contaminated sites. There is growing concern that use of conventional PRB?s, such as zero-valent iron, are a temporary solution to a problem that will persist for thousands of years. Alternatives to the standard treatment methods are therefore warranted. The core objective of our research is to demonstrate that a phosphorous amendment strategy will result in a reduction of dissolved uranium to below the proposed drinking water standard. Our hypothesis is that long-chain polyphosphate compounds forestall precipitation of sparingly soluble uranyl phosphate compounds, which is key to preventing fouling of wells at the point of injection. Our other fundamental objective is to synthesize and correctly characterize the uranyl phosphate phases that form in the geochemical conditions under consideration. This report summarizes work conducted at the University of Notre Dame through November of 2003 under DOE grant DE-FG07-02ER63489, which has been funded since September, 2002. The objectives at Notre Dame are development of synthesis techniques for uranyl phosphate phases, together with detailed structural and chemical characterization of the myriad of uranyl phosphate phases that may form under geochemical conditions under consideration.

  10. Material property correlations for uranium mononitride 

    E-Print Network [OSTI]

    Hayes, Steven Lowe

    1989-01-01T23:59:59.000Z

    who have provided technical support for this project throughout its duration. I also express my sincere appreciation and thanks to the U. S. Department of Energy and Oak Ridge Associated Universities whose Nuclear Engineering and Health Physics... space nuclear reactors. Uranium mononitride is currently the reference fuel for the SP-100 space reactor system and will likely be considered for application in future multimegawatt space power systems as well. Although fuel modeling efforts have...

  11. Uranio impoverito: perché? (Depleted uranium: why?)

    E-Print Network [OSTI]

    Germano D'Abramo

    2003-06-05T23:59:59.000Z

    In this paper we develop a simple model of the penetration process of a long rod through an uniform target. Applying the momentum and energy conservation laws, we derive an analytical relation which shows how the penetration depth depends upon the density of the rod, given a fixed kinetic energy. This work was sparked off by the necessity of understanding the effectiveness of high density penetrators (e.g. depleted uranium penetrators) as anti-tank weapons.

  12. Plutonium Uranium Extraction Facility Documented Safety Analysis

    SciTech Connect (OSTI)

    DODD, E.N.

    2003-10-08T23:59:59.000Z

    This document provides the documented safety analysis (DSA) and Central Plateau Remediation Project (CP) requirements that apply to surveillance and maintenance (S&M) activities at the Plutonium-Uranium Extraction (PUREX) facility. This DSA was developed in accordance with DOE-STD-1120-98, ''Integration of Environment, Safety, and Health into Facility Disposition Activities''. Upon approval and implementation of this document, the current safety basis documents will be retired.

  13. Upscaling of U(VI) Desorption and Transport Using Decimeter-Scale Tanks

    SciTech Connect (OSTI)

    Rodriguez, Derrick [Colorado School of Mines

    2014-12-22T23:59:59.000Z

    Experimental work was used to validate modeling studies and develop multicontinuum models of U(VI) transport in a contaminated aquifer. At the bench scale, it has been shown that U(VI) desorption is rate-limited and that rates are dependent on the bicarbonate concentration. Two decimeter-scale experiments were conducted in order to help establish rigorous upscaling approaches that could be tested at the tracer test and plume scales.

  14. Influences of Water Vapor on Cr(VI) Reduction by Gaseous Hydrogen

    E-Print Network [OSTI]

    Deng, Baolin

    Columbia, Columbia, Missouri 65211 In Situ Gaseous Reduction (ISGR) using hydrogen sulfide (H2S) is a technology the contaminants, H2S, and various soil components. In this study, Cr(VI) reduction by gaseous H2S was examined under various relative humidities (0-96.7%), concentrations of Cr(VI) (127-475 µg/g of solid), and H2S

  15. Measurement of uranium enrichment by gamma spectroscopy: result of an experimental design

    E-Print Network [OSTI]

    , Gamma Spectrometry, uranium enrichment #12;PAPER Measurement of uranium enrichment by gamma spectroscopy: result of an experimental design Gamma spectroscopy is commonly used in nuclear safeguards to measure uranium enrichment. An experimental

  16. Uranium Recovery from Seawater: Development of Fiber Adsorbents Prepared via Atom-Transfer Radical Polymerization

    SciTech Connect (OSTI)

    Saito, Tomonori; Brown, Suree; Chatterjee, Sabornie; Kim, Jungseung; Tsouris, Constantinos; Mayes, Richard; Kuo, Li-Jung; Gill, Gary A.; Oyola, Yatsandra; Janke, C.; Dai, Sheng

    2014-07-09T23:59:59.000Z

    Uranium exists uniformly at a concentration of ~3.3 ppb in seawater. The extraction of uranium from seawater presents a very attractive alternative source of uranium for nuclear fuel needs.

  17. Magnetic Exchange Coupling and Single-Molecule Magnetism in Uranium Complexes

    E-Print Network [OSTI]

    Rinehart, Jeffrey Dennis

    2010-01-01T23:59:59.000Z

    in molecular uranium cluster chemistry. 13 Compound 2 ischemistry and small-molecule reactivity of uranium. AmongUranium Complexes by Jeffrey Dennis Rinehart Doctor of Philosophy in Chemistry

  18. Recent International R&D Activities in the Extraction of Uranium from Seawater

    E-Print Network [OSTI]

    Rao, Linfeng

    2011-01-01T23:59:59.000Z

    Uranium and Rare Earth Elements Using Biomass of Algae, Bioinorganic Chemistry andRecovery of uranium from sea water. Chemistry & Industry (of uranium from seawater. Turkish Journal of Chemistry, 17 (

  19. The geochemistry of uranium in the Orca Basin

    E-Print Network [OSTI]

    Weber, Frederick Fewell

    1979-01-01T23:59:59.000Z

    . , 1974). Substantial uranium enrichments have been reported by many investigators for samples taken from aroxic environments (Strom, 1948; Starik et al. , '1961; Swanson, 1961; Sackett and Cook, 1969; Kolodny and Kaplan, 1969; Bertine et al. , 1970...) ~ Degens et al. , (1977) report concentrations of uranium as high as 60ppm, more than an order of magnitude enrich- meut, for Black Sea sediments. If marine reducing environments are found with uranium concentrations apuroaching 100ppm, they will begin...

  20. The geochemistry of uranium in the Orca Basin 

    E-Print Network [OSTI]

    Weber, Frederick Fewell

    1979-01-01T23:59:59.000Z

    as uranium concentrations dzop to an average of 2. dppm, indicative of relatively low uranium bearing pelagic particle deposition. Furthermore, the 13 C values become heavier in this region, lacking a large terrest. rial component. This evidence suggests... 39 the basin walls. It may be possible that these particles at the brine/seawater interface incorporate any uranium reduced in this zone and carry it to the brine perimeter where it is deposited. Unfortunately, attempts to accurately core...

  1. Release of U(VI) from spent biosorbent immobilized in cement concrete blocks

    SciTech Connect (OSTI)

    Venkobachar, C.; Iyengar, L.; Mishra, U.K.; Chauhan, M.S. [Indian Inst. of Tech., Kanpur (India)] [Indian Inst. of Tech., Kanpur (India)

    1995-12-01T23:59:59.000Z

    This paper deals with cementation as the method for the disposal of spent biosorbent, Ganoderma lucidum (a wood rotting macrofungi) after it is used for the removal of Uranium. Results on the uranium release during the curing of cement-concrete (CC) blocks indicated that placing the spent sorbent at the center of the blocks during their casting yields better immobilization of uranium as compared to the homogeneous mixing of the spent sorbent with the cement. Short term leach tests indicated that the uranium release was negligible in simulated seawater, 1.8% in 0.2 N sodium carbonate and 6.0% in 0.2 N HCl. The latter two leachates were used to represent the extreme environmental conditions. It was observed that the presence of the spent biosorbent up to 5% by weight did not affect the compressive strength of CC blocks. Thus cementation technique is suitable for the immobilization of uranium loaded biosorbent for its ultimate disposal.

  2. National Uranium Resource Evaluation: Salina Quadrangle, Utah

    SciTech Connect (OSTI)

    Lupe, R.D.; Campbell, J.A.; Franczyk, K.J.; Luft, S.J.; Peterson, F.; Robinson, K.

    1982-09-01T23:59:59.000Z

    Two stratigraphic units, the Late Jurassic Salt Wash Member of the Morrison Formation and the Triassic Chinle Formation, were determined to be favorable for the occurrence of uranium deposits that meet the minimum size and grade requirements of the US Department of Energy in the Salina 1 x 2/sup 0/ Quadrangle, Utah. Three areas judged favorable for the Salt Wash Member are the Tidwell and Notom districts, and the Henry Mountains mineral belt. The criteria used to establish favorability were the presence of: (1) fluvial sandstone beds deposited by low-energy streams; (2) actively moving major and minor structures such as the Paradox basin and the many folds within it; (3) paleostream transport directions approximately perpendicular to the trend of many of the paleofolds; (4) presence of favorable gray lacustrine mudstone beds; and (5) known uranium occurrences associated with the favorable gray mudstones. Four favorable areas have been outlined for the Chinle Formation. These are the San Rafael Swell, Inter River, and the Orange Cliffs subareas and the Capitol Reef area. The criteria used to establish these areas are: the sandstone-to-mudstone ratios and the geographic distribution of the Petrified Forest Member of the Chinle Formation which is considered as the probable source for the uranium.

  3. Uncertainty clouds uranium enrichment corporation's plans

    SciTech Connect (OSTI)

    Lane, E.

    1993-03-24T23:59:59.000Z

    An expected windfall to the US Treasury from the sale of the Energy Dept.'s commercial fuel enrichment facilities may evaporate in the next few weeks when the Clinton administration submits its fiscal 1994 budget proposal to Congress, according to congressional and administration officials. Under the Energy Policy Act of 1992, DOE is required to lease two uranium enrichment facilities, Portsmouth, Ohio, and Paducah, KY., to the government-owned US Enrichment Corp. (USEC) by July 1. Estimates by OMB and Treasury indicate a potential yearly payoff of $300 million from the government-owned company's sale of fuel for commercial reactors. Those two facilities use a process of gaseous diffusion to enrich uranium to about 3 percent for use as fuel in commercial power plants. DOE has contracts through at least 1996 to provide about 12 million separative work units (SWUs) yearly to US utilities and others world-wide. But under an agreement signed between the US and Russia last August, at least 10 metric tons, or 1.5 million SWUs, of low-enriched uranium (LEU) blended down from Russia warheads is expected to be delivered to the US starting in 1994. It could be sold at $50 to $60 per SWU, far below what DOE currently charges for its SWUs - $135 per SWU for 70 percent of the contract price and $90 per SWU for the remaining 30 percent.

  4. Chapter 3. Volume and Characteristics of Uranium Mine Wastes Uranium has been found and mined in a wide variety of rocks, including sandstone, carbonates1

    E-Print Network [OSTI]

    3-1 Chapter 3. Volume and Characteristics of Uranium Mine Wastes Uranium has been found and mined conventional mining, solution extraction, and milling of uranium, a principal focus of this report is TENORM, or which may need future reclamation. When uranium mining first started, most of the ores were recovered

  5. Control of structure and reactivity by ligand design : applications to small molecule activation by low-valent uranium complexes

    E-Print Network [OSTI]

    Lam, Oanh Phi

    2010-01-01T23:59:59.000Z

    coordination chemistry is depleted uranium, a by-product innuclear reactors. Depleted uranium Figure 1-1. The periodic

  6. Uranium from Seawater Program Review; Fuel Resources Uranium from Seawater Program DOE Office of Nuclear Energy

    SciTech Connect (OSTI)

    none,

    2013-07-01T23:59:59.000Z

    For nuclear energy to remain sustainable in the United States, economically viable sources of uranium beyond terrestrial ores must be developed. The goal of this program is to develop advanced adsorbents that can extract uranium from seawater at twice the capacity of the best adsorbent developed by researchers at the Japan Atomic Energy Agency (JAEA), 1.5 mg U/g adsorbent. A multidisciplinary team from Oak Ridge National Laboratory, Lawrence Berkeley National Laboratory, Pacific Northwest National Laboratory, and the University of Texas at Austin was assembled to address this challenging problem. Polymeric adsorbents, based on the radiation grafting of acrylonitrile and methacrylic acid onto high surface-area polyethylene fibers followed by conversion of the nitriles to amidoximes, have been developed. These poly(acrylamidoxime-co-methacrylic acid) fibers showed uranium adsorption capacities for the extraction of uranium from seawater that exceed 3 mg U/g adsorbent in testing at the Pacific Northwest National Laboratory Marine Sciences Laboratory. The essence of this novel technology lies in the unique high surface-area trunk material that considerably increases the grafting yield of functional groups without compromising its mechanical properties. This technology received an R&D100 Award in 2012. In addition, high surface area nanomaterial adsorbents are under development with the goal of increasing uranium adsorption capacity by taking advantage of the high surface areas and tunable porosity of carbon-based nanomaterials. Simultaneously, de novo structure-based computational design methods are being used to design more selective and stable ligands and the most promising candidates are being synthesized, tested and evaluated for incorporation onto a support matrix. Fundamental thermodynamic and kinetic studies are being carried out to improve the adsorption efficiency, the selectivity of uranium over other metals, and the stability of the adsorbents. Understanding the rate-limiting step of uranium uptake from seawater is also essential in designing an effective uranium recovery system. Finally, economic analyses have been used to guide these studies and highlight what parameters, such as capacity, recyclability, and stability, have the largest impact on the cost of extraction of uranium from seawater. Initially, the cost estimates by the JAEA for extraction of uranium from seawater with braided polymeric fibers functionalized with amidoxime ligands were evaluated and updated. The economic analyses were subsequently updated to reflect the results of this project while providing insight for cost reductions in the adsorbent development through “cradle-to-grave” case studies for the extraction process. This report highlights the progress made over the last three years on the design, synthesis, and testing of new materials to extract uranium for seawater. This report is organized into sections that highlight the major research activities in this project: (1) Chelate Design and Modeling, (2) Thermodynamics, Kinetics and Structure, (3) Advanced Polymeric Adsorbents by Radiation Induced Grafting, (4) Advanced Nanomaterial Adsorbents, (5) Adsorbent Screening and Modeling, (6) Marine Testing, and (7) Cost and Energy Assessment. At the end of each section, future research directions are briefly discussed to highlight the challenges that still remain to reduce the cost of extractions of uranium for seawater. Finally, contributions from the Nuclear Energy University Programs (NEUP), which complement this research program, are included at the end of this report.

  7. Chromium Isotope Fractionation During Reduction of Cr(VI) Under Saturated Flow Conditions

    SciTech Connect (OSTI)

    Jamieson-Hanes, Julia H.; Gibson, Blair D.; Lindsay, Matthew B.J.; Kim, Yeongkyoo; Ptacek, Carol J.; Blowes, David W. (Waterloo); (Kyungpook National University)

    2012-10-25T23:59:59.000Z

    Chromium isotopes are potentially useful indicators of Cr(VI) reduction reactions in groundwater flow systems; however, the influence of transport on Cr isotope fractionation has not been fully examined. Laboratory batch and column experiments were conducted to evaluate isotopic fractionation of Cr during Cr(VI) reduction under both static and controlled flow conditions. Organic carbon was used to reduce Cr(VI) in simulated groundwater containing 20 mg L{sup -1} Cr(VI) in both batch and column experiments. Isotope measurements were performed on dissolved Cr on samples from the batch experiments, and on effluent and profile samples from the column experiment. Analysis of the residual solid-phase materials by scanning electron microscopy (SEM) and by X-ray absorption near edge structure (XANES) spectroscopy confirmed association of Cr(III) with organic carbon in the column solids. Decreases in dissolved Cr(VI) concentrations were coupled with increases in {delta}{sup 53}Cr, indicating that Cr isotope enrichment occurred during reduction of Cr(VI). The {delta}{sup 53}Cr data from the column experiment was fit by linear regression yielding a fractionation factor ({alpha}) of 0.9979, whereas the batch experiments exhibited Rayleigh-type isotope fractionation ({alpha} = 0.9965). The linear characteristic of the column {delta}{sup 53}Cr data may reflect the contribution of transport on Cr isotope fractionation.

  8. Uranium immobilization by sulfate-reducing biofilms grown on...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of uranium-complexing carbonates. The biofilms were grown in three identically operated fixed bed reactors, filled with three types of minerals: one noncarbonate-bearing...

  9. Assessment of Controlling Processes for Field-Scale Uranium Reactive...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    at the 300A site. However, the model simulations also revealed that the groundwater chemistry was relatively stable during the uranium tracer experiment and therefore...

  10. Secretarial Determination of No Adverse Material Impact for Uranium...

    Energy Savers [EERE]

    set forth in the 2012 Secretarial Determination and the Department's Excess Uranium Inventory Management Plan released in July 2013. Secretarial Determination 5-15-14.pdf More...

  11. Assessment of Controlling Processes for Field-Scale Uranium Reactive...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    reactive transport model was employed to assess the key factors and processes that control the field-scale uranium reactive transport. Taking into consideration of relevant...

  12. Uranium-contaminated soils: Ultramicrotomy and electron beam analysis

    SciTech Connect (OSTI)

    Buck, E.C.; Dietz, N.L.; Bates, J.K.; Cunnane, J.C.

    1994-04-01T23:59:59.000Z

    Uranium contaminated soils from the Fernald Operation Site, Ohio, have been examined by a combination of optical microscopy, scanning electron microscopy with backscattered electron detection (SEM/BSE), and analytical electron microscopy (AEM). A method is described for preparing of transmission electron microscopy (TEM) thin sections by ultramicrotomy. By using these thin sections, SEM and TEM images can be compared directly. Uranium was found in iron oxides, silicates (soddyite), phosphates (autunites), and fluorite. Little uranium was associated with clays. The distribution of uranium phases was found to be inhomogeneous at the microscopic level.

  13. High grade uranium resources in the United States : an overview

    E-Print Network [OSTI]

    Graves, Richard E.

    1974-01-01T23:59:59.000Z

    A time analysis of uranium exploration, production and known reserves in the United States is employed to reveal industry trends. The

  14. The radioactive Substances (Prepared Uranium Thorium Compounds) Exemption Order 1962 

    E-Print Network [OSTI]

    Joseph, Keith

    1962-01-01T23:59:59.000Z

    STATUTORY INSTRUMENTS 1962 No. 2711 ATOMIC ENERGY AND RADIOACI1VE SUBSTANCES The Radioactive Substances (prepared Uranium and Thorium Compounds) Exemption Order 1962...

  15. EIS-0472: Uranium Leasing Program, Mesa, Montrose, and San Miguel...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Leasing Program, under which DOE administers tracts of land in western Colorado for exploration, development, and the extraction of uranium and vanadium ores. The cooperating...

  16. Financial Assurance for In Situ Uranium Facilities (Texas)

    Broader source: Energy.gov [DOE]

    Owners or operators are required to provide financial assurance for in situ uranium sites. This money is required for: decommissioning, decontamination, demolition, and waste disposal for buildings...

  17. President Truman Increases Production of Uranium and Plutonium...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Increases Production of Uranium and Plutonium | National Nuclear Security Administration Facebook Twitter Youtube Flickr RSS People Mission Managing the Stockpile Preventing...

  18. NNSA Authorizes Start-Up of Highly Enriched Uranium Materials...

    National Nuclear Security Administration (NNSA)

    Authorizes Start-Up of Highly Enriched Uranium Materials Facility at Y-12 | National Nuclear Security Administration Facebook Twitter Youtube Flickr RSS People Mission Managing the...

  19. Uranium Leasing Program Draft PEIS Public Comment Period Extended...

    Broader source: Energy.gov (indexed) [DOE]

    Uranium Leasing Program Draft PEIS Public Comment Period Extended to May 31, 2013 Draft ULPEIS comment extension community notification041813 (3).pdf More Documents & Publications...

  20. Electrochemical method of producing eutectic uranium alloy and apparatus

    DOE Patents [OSTI]

    Horton, J.A.; Hayden, H.W.

    1995-01-10T23:59:59.000Z

    An apparatus and method are disclosed for continuous production of liquid uranium alloys through the electrolytic reduction of uranium chlorides. The apparatus includes an electrochemical cell formed from an anode shaped to form an electrolyte reservoir, a cathode comprising a metal, such as iron, capable of forming a eutectic uranium alloy having a melting point less than the melting point of pure uranium, and molten electrolyte in the reservoir comprising a chlorine or fluorine containing salt and uranium chloride. The method of the invention produces an eutectic uranium alloy by creating an electrolyte reservoir defined by a container comprising an anode, placing an electrolyte in the reservoir, the electrolyte comprising a chlorine or fluorine containing salt and uranium chloride in molten form, positioning a cathode in the reservoir where the cathode comprises a metal capable of forming an uranium alloy having a melting point less than the melting point of pure uranium, and applying a current between the cathode and the anode. 2 figures.