Sample records for uranium dioxide uo

  1. Computational Investigation of the Formation of Hyper-stoichiometric Uranium Dioxide (UO{sub 2+x})

    SciTech Connect (OSTI)

    Skomurski, Frances; Becker, Udo; Ewing, Rodney [Geological Sciences, University of Michigan, 2534 C.C. Little Building, 1100 North University Ave., Ann Arbor, MI, 48109 (United States)

    2007-07-01T23:59:59.000Z

    Understanding the mechanisms behind the formation of hyper-stoichiometric UO{sub 2} phases is important because oxidation of uranium atoms upon the addition of excess oxygen to the UO{sub 2} structure leads to volume changes that increase the susceptibility of spent fuel to corrosion. While a variety of diffraction and spectroscopic studies have been used to investigate structural changes as UO{sub 2} oxidizes to U{sub 4}O{sub 9}, the effect of interstitial oxygen on the charge distribution of uranium in hyper-stoichiometric UO{sub 2} remains inconclusive. In this study, quantum mechanical techniques were used to model the effects of interstitial oxygen on the structure and charge distribution of atoms in a simplified U{sub 4}O{sub 9} unit cell. A density functional theory-based approach was used to optimize the geometry and charge distribution of a variety of U{sub 4}O{sub 9} starting models with different U{sup 4+}, U{sup 5+} and U{sup 6+} charge configurations. Results from our calculations suggest that the formation of one U{sup 5+} per addition of interstitial oxygen at a perpendicular bisector site is favorable; this oxidation event is accompanied by partial reduction of the interstitial oxygen atom. Deflection of two lattice oxygen atoms along the body diagonal of the cubic site surrounding the U{sup 5+} is also observed upon the addition of one interstitial oxygen atom. Structural and bond length data are compared with experimental data whenever possible. (authors)

  2. 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.

  3. Molten uranium dioxide structure and dynamics

    SciTech Connect (OSTI)

    Skinner, L. B. [Argonne National Laboratory (ANL), Argonne, IL (United States); Stony Brook Univ., Stony Brook, NY (United States); Materials Development Inc., Arlington Heights, IL (United States); Parise, J. B. [Stony Brook Univ., Stony Brook, NY (United States); Benmore, C. J. [Argonne National Laboratory (ANL), Argonne, IL (United States); Weber, J. K.R. [Materials Development Inc., Arlington Heights, IL (United States); Williamson, M. A. [Argonne National Laboratory (ANL), Argonne, IL (United States); Tamalonis, A. [Materials Development Inc., Arlington Heights, IL (United States); Hebden, A. [Argonne National Laboratory (ANL), Argonne, IL (United States); Wiencek, T. [Argonne National Laboratory (ANL), Argonne, IL (United States); Alderman, O. L.G. [Materials Development Inc., Arlington Heights, IL (United States); Guthrie, M. [Carnegie Inst., Washington, DC (United States); Leibowitz, L. [Argonne National Laboratory (ANL), Argonne, IL (United States)

    2014-11-20T23:59:59.000Z

    Uranium dioxide (UO2) is the major nuclear fuel component of fission power reactors. A key concern during severe accidents is the melting and leakage of radioactive UO2 as it corrodes through its zirconium cladding and steel containment. Yet, the very high temperatures (>3140 kelvin) and chemical reactivity of molten UO2 have prevented structural studies. In this work, we combine laser heating, sample levitation, and synchrotron x-rays to obtain pair distribution function measurements of hot solid and molten UO2. The hot solid shows a substantial increase in oxygen disorder around the lambda transition (2670 K) but negligible U-O coordination change. On melting, the average U-O coordination drops from 8 to 6.7 ± 0.5. Molecular dynamics models refined to this structure predict higher U-U mobility than 8-coordinated melts.

  4. Molten uranium dioxide structure and dynamics

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

    Skinner, L. B. [Argonne National Laboratory (ANL), Argonne, IL (United States); Stony Brook Univ., Stony Brook, NY (United States); Materials Development Inc., Arlington Heights, IL (United States); Parise, J. B. [Stony Brook Univ., Stony Brook, NY (United States); Benmore, C. J. [Argonne National Laboratory (ANL), Argonne, IL (United States); Weber, J. K.R. [Materials Development Inc., Arlington Heights, IL (United States); Williamson, M. A. [Argonne National Laboratory (ANL), Argonne, IL (United States); Tamalonis, A. [Materials Development Inc., Arlington Heights, IL (United States); Hebden, A. [Argonne National Laboratory (ANL), Argonne, IL (United States); Wiencek, T. [Argonne National Laboratory (ANL), Argonne, IL (United States); Alderman, O. L.G. [Materials Development Inc., Arlington Heights, IL (United States); Guthrie, M. [Carnegie Inst., Washington, DC (United States); Leibowitz, L. [Argonne National Laboratory (ANL), Argonne, IL (United States)

    2014-11-20T23:59:59.000Z

    Uranium dioxide (UO2) is the major nuclear fuel component of fission power reactors. A key concern during severe accidents is the melting and leakage of radioactive UO2 as it corrodes through its zirconium cladding and steel containment. Yet, the very high temperatures (>3140 kelvin) and chemical reactivity of molten UO2 have prevented structural studies. In this work, we combine laser heating, sample levitation, and synchrotron x-rays to obtain pair distribution function measurements of hot solid and molten UO2. The hot solid shows a substantial increase in oxygen disorder around the lambda transition (2670 K) but negligible U-O coordination change. On melting, the average U-O coordination drops from 8 to 6.7 ± 0.5. Molecular dynamics models refined to this structure predict higher U-U mobility than 8-coordinated melts.

  5. Molten uranium dioxide structure and dynamics

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

    Skinner, L. B.; Parise, J. B.; Benmore, C. J.; Weber, J. K.R.; Williamson, M. A.; Tamalonis, A.; Hebden, A.; Wiencek, T.; Alderman, O. L.G.; Guthrie, M.; et al

    2014-11-20T23:59:59.000Z

    Uranium dioxide (UO2) is the major nuclear fuel component of fission power reactors. A key concern during severe accidents is the melting and leakage of radioactive UO2 as it corrodes through its zirconium cladding and steel containment. Yet, the very high temperatures (>3140 kelvin) and chemical reactivity of molten UO2 have prevented structural studies. In this work, we combine laser heating, sample levitation, and synchrotron x-rays to obtain pair distribution function measurements of hot solid and molten UO2. The hot solid shows a substantial increase in oxygen disorder around the lambda transition (2670 K) but negligible U-O coordination change. Onmore »melting, the average U-O coordination drops from 8 to 6.7 ± 0.5. Molecular dynamics models refined to this structure predict higher U-U mobility than 8-coordinated melts.« less

  6. Standard specification for sintered gadolinium oxide-uranium dioxide pellets

    E-Print Network [OSTI]

    American Society for Testing and Materials. Philadelphia

    2008-01-01T23:59:59.000Z

    1.1 This specification is for finished sintered gadolinium oxide-uranium dioxide pellets for use in light-water reactors. It applies to gadolinium oxide-uranium dioxide pellets containing uranium of any 235U concentration and any concentration of gadolinium oxide. 1.2 This specification recognizes the presence of reprocessed uranium in the fuel cycle and consequently defines isotopic limits for gadolinium oxide-uranium dioxide pellets made from commercial grade UO2. Such commercial grade UO2 is defined so that, regarding fuel design and manufacture, the product is essentially equivalent to that made from unirradiated uranium. UO2 falling outside these limits cannot necessarily be regarded as equivalent and may thus need special provisions at the fuel fabrication plant or in the fuel design. 1.3 This specification does not include (1) provisions for preventing criticality accidents or (2) requirements for health and safety. Observance of this specification does not relieve the user of the obligation to be aw...

  7. Influence of zirconium and niobium on cathodic deposition of uranium dioxide from alkali chloride melts

    SciTech Connect (OSTI)

    Komarov, V.E.; Borodina, N.P.; Martem`yanova, Z.S. [Institute of High-Temperature Electrochemistry, Ekaterinburg (Russian Federation)

    1995-07-01T23:59:59.000Z

    Electrocrystallization of uranium dioxide from molten chloride electrolytes in the presence of zirconium(IV) and niobium(V) was studied by voltammetry. Zirconium(IV) was found to react with uranium dioxide according to exchange mechanism to form (1 - x)UO{sub 2}{center_dot}xZrO{sub 2} solid solutions. Niobium(IV), a product of cathodic reduction of niobium(V), enters into the exchange reaction with uranium dioxide to yield (1 - y)UO{sub 2{center_dot}y}NbO{sub 2} solid solutions. In the case of simultaneous presence of Nb(V) and Zr(IV) in electrolyte, ternary (1 - x - y)UO{sub 2 {center_dot}x}ZrO{sub 2{center_dot}y}NbO{sub 2} solid solutions are obtained at the cathode surface. Nucleation of the solid solutions phase was shown to occurs at the most active sites of the crystalline precipitate of uranium dioxide.

  8. Diffusion model of the non-stoichiometric uranium dioxide

    SciTech Connect (OSTI)

    Moore, Emily, E-mail: emily.moore@cea.fr [CEA Saclay, DEN-DPC-SCCME, 91191 Gif-sur-Yvette Cedex (France); Guéneau, Christine, E-mail: christine.gueneau@cea.fr [CEA Saclay, DEN-DPC-SCCME, 91191 Gif-sur-Yvette Cedex (France); Crocombette, Jean-Paul, E-mail: jean-paul.crocombette@cea.fr [CEA Saclay, DEN DEN, Service de Recherches de Métallurgie Physique, 91191 Gif-sur-Yvette Cedex (France)

    2013-07-15T23:59:59.000Z

    Uranium dioxide (UO{sub 2}), which is used in light water reactors, exhibits a large range of non-stoichiometry over a wide temperature scale up to 2000 K. Understanding diffusion behavior of uranium oxides under such conditions is essential to ensure safe reactor operation. The current understanding of diffusion properties is largely limited by the stoichiometric deviations inherent to the fuel. The present DICTRA-based model considers diffusion across non-stoichiometric ranges described by experimentally available data. A vacancy and interstitial model of diffusion is applied to the U–O system as a function of its defect structure derived from CALPHAD-type thermodynamic descriptions. Oxygen and uranium self and tracer diffusion coefficients are assessed for the construction of a mobility database. Chemical diffusion coefficients of oxygen are derived with respect to the Darken relation and migration energies of defects are evaluated as a function of stoichiometric deviation. - Graphical abstract: Complete description of Oxygen–Uranium diffusion as a function of composition at various temperatures according to the developed Dictra model. - Highlights: • Assessment of a uranium–oxygen diffusion model with Dictra. • Complete description of U–O diffusion over wide temperature and composition range. • Oxygen model includes terms for interstitial and vacancy migration. • Interaction terms between defects help describe non-stoichiometric domain of UO{sub 2±x}. • Uranium model is separated into mobility terms for the cationic species.

  9. Helium Migration Mechanisms in Polycrystalline Uranium Dioxide

    SciTech Connect (OSTI)

    Martin, Guillaume; Desgardin, Pierre; Sauvage, Thierry; Barthe, Marie-France [CERI, CNRS, 3 A rue de la Ferollerie, ORLEANS, 45071 (France); Garcia, Philippe; Carlot, Gaelle [DEN/DEC/SESC/LLCC, CEA Cadarache, Saint Paul Lez Durance, 13108 (France)

    2007-07-01T23:59:59.000Z

    This study aims at identifying the release mechanisms of helium in uranium dioxide. Two sets of polycrystalline UO{sub 2} sintered samples presenting different microstructures were implanted with {sup 3}He ions at concentrations in the region of 0.1 at.%. Changes in helium concentrations were monitored using two Nuclear Reaction Analysis (NRA) techniques based on the {sup 3}He(d,{alpha}){sup 1}H reaction. {sup 3}He release is measured in-situ during sample annealing at temperatures ranging between 700 deg. C and 1000 deg. C. Accurate helium depth profiles are generated after each annealing stage. Results that provide data for further understanding helium release mechanisms are discussed. It is found that helium diffusion appears to be enhanced above 900 deg. C in the vicinity of grain boundaries possibly as a result of the presence of defects. (authors)

  10. 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 ...

  11. Selective Extraction of Uranium from Liquid or Supercritical Carbon Dioxide

    SciTech Connect (OSTI)

    Farawila, Anne F.; O'Hara, Matthew J.; Wai, Chien M.; Taylor, Harry Z.; Liao, Yu-Jung

    2012-07-31T23:59:59.000Z

    Current liquid-liquid extraction processes used in recycling irradiated nuclear fuel rely on (1) strong nitric acid to dissolve uranium oxide fuel, and (2) the use of aliphatic hydrocarbons as a diluent in formulating the solvent used to extract uranium. The nitric acid dissolution process is not selective. It dissolves virtually the entire fuel meat which complicates the uranium extraction process. In addition, a solvent washing process is used to remove TBP degradation products, which adds complexity to the recycling plant and increases the overall plant footprint and cost. A liquid or supercritical carbon dioxide (l/sc -CO2) system was designed to mitigate these problems. Indeed, TBP nitric acid complexes are highly soluble in l/sc -CO2 and are capable of extracting uranium directly from UO2, UO3 and U3O8 powders. This eliminates the need for total acid dissolution of the irradiated fuel. Furthermore, since CO2 is easily recycled by evaporation at room temperature and pressure, it eliminates the complex solvent washing process. In this report, we demonstrate: (1) A reprocessing scheme starting with the selective extraction of uranium from solid uranium oxides into a TBP-HNO3 loaded Sc-CO2 phase, (2) Back extraction of uranium into an aqueous phase, and (3) Conversion of recovered purified uranium into uranium oxide. The purified uranium product from step 3 can be disposed of as low level waste, or mixed with enriched uranium for use in a reactor for another fuel cycle. After an introduction on the concept and properties of supercritical fluids, we first report the characterization of the different oxides used for this project. Our extraction system and our online monitoring capability using UV-Vis absorbance spectroscopy directly in sc-CO2 is then presented. Next, the uranium extraction efficiencies and kinetics is demonstrated for different oxides and under different physical and chemical conditions: l/sc -CO2 pressure and temperature, TBP/HNO3 complex used, reductant or complexant used for selectivity, and ionic liquids used as supportive media. To complete the extraction and recovery cycle, we then demonstrate uranium back extraction from the TBP loaded sc-CO2 phase into an aqueous phase and the characterization of the uranium complex formed at the end of this process. Another aspect of this project was to limit proliferation risks by either co-extracting uranium and plutonium, or by leaving plutonium behind by selectively extracting uranium. We report that the former is easily achieved, since plutonium is in the tetravalent or hexavalent oxidation state in the oxidizing environment created by the TBP-nitric acid complex, and is therefore co-extracted. The latter is more challenging, as a reductant or complexant to plutonium has to be used to selectively extract uranium. After undertaking experiments on different reducing or complexing systems (e.g., AcetoHydroxamic Acid (AHA), Fe(II), ascorbic acid), oxalic acid was chosen as it can complex tetravalent actinides (Pu, Np, Th) in the aqueous phase while allowing the extraction of hexavalent uranium in the sc-CO2 phase. Finally, we show results using an alternative media to commonly used aqueous phases: ionic liquids. We show the dissolution of uranium in ionic liquids and its extraction using sc-CO2 with and without the presence of AHA. The possible separation of trivalent actinides from uranium is also demonstrated in ionic liquids using neodymium as a surrogate and diglycolamides as the extractant.

  12. Production of small uranium dioxide microspheres for cermet nuclear fuel using the internal gelation process

    SciTech Connect (OSTI)

    Collins, Robert T [ORNL] [ORNL; Collins, Jack Lee [ORNL] [ORNL; Hunt, Rodney Dale [ORNL] [ORNL; Ladd-Lively, Jennifer L [ORNL] [ORNL; Patton, Kaara K [ORNL] [ORNL; Hickman, Robert [NASA Marshall Space Flight Center, Huntsville, AL] [NASA Marshall Space Flight Center, Huntsville, AL

    2014-01-01T23:59:59.000Z

    The U.S. National Aeronautics and Space Administration (NASA) is developing a uranium dioxide (UO2)/tungsten cermet fuel for potential use as the nuclear cryogenic propulsion stage (NCPS). The first generation NCPS is expected to be made from dense UO2 microspheres with diameters between 75 and 150 m. Previously, the internal gelation process and a hood-scale apparatus with a vibrating nozzle were used to form gel spheres, which became UO2 kernels with diameters between 350 and 850 m. For the NASA spheres, the vibrating nozzle was replaced with a custom designed, two-fluid nozzle to produce gel spheres in the desired smaller size range. This paper describes the operational methodology used to make 3 kg of uranium oxide microspheres.

  13. Thermal Reactions of Uranium Metal, UO2, U3O8, UF4, and UO2F2 with NF3 to Produce UF6

    SciTech Connect (OSTI)

    McNamara, Bruce K.; Scheele, Randall D.; Kozelisky, Anne E.; Edwards, Matthew K.

    2009-11-01T23:59:59.000Z

    he objective of this paper is to demonstrate that NF3 fluorinates uranium metal, UO2, UF4, UO3, U3O8, and UO2F2•2H2O to produce the volatile UF6 at temperatures between 100 and 500?C. Thermogravimetric reaction profiles are described that reflect changes in the uranium oxidation state and discrete chemical speciation. Differences in the onset temperatures for each system indicate that NF3-substrate interactions are important for the temperature at which NF3 reacts: U metal > UO3 > UO2 > UO2F2 > UF4 and in fact may indicate different fluorination mechanisms for these various substrates. These studies demonstrate that NF3 is a potential replacement fluorinating agent in the existing nuclear fuel cycle and in oft-proposed actinide volatility reprocessing.

  14. Spin-lattice coupling in uranium dioxide probed by magnetostriction measurements at high magnetic fields (P08358-E001-PF)

    SciTech Connect (OSTI)

    K. Gofryk; M. Jaime

    2014-12-01T23:59:59.000Z

    Conclusions Our preliminary magnetostriction measurements have already shown a strong interplay of lattice dynamic and magnetism in both antiferromagnetic and paramagnetic states, and give unambiguous evidence of strong spin- phonon coupling in uranium dioxide. Further studies are planned to address the puzzling behavior of UO2 in magnetic and paramagnetic states and details of the spin-phonon coupling.

  15. 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

  16. Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade uranium dioxide powders and pellets

    E-Print Network [OSTI]

    American Society for Testing and Materials. Philadelphia

    1999-01-01T23:59:59.000Z

    1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade uranium dioxide powders and pellets to determine compliance with specifications. 1.2 This test method covers the determination of uranium and the oxygen to uranium atomic ratio in nuclear-grade uranium dioxide powder and pellets. 1.4 This test method covers the determination of chlorine and fluorine in nuclear-grade uranium dioxide. With a 1 to 10-g sample, concentrations of 5 to 200 g/g of chlorine and 1 to 200 ?g/g of fluorine are determined without interference. 1.5 This test method covers the determination of moisture in uranium dioxide samples. Detection limits are as low as 10 ?g. 1.6 This test method covers the determination of nitride nitrogen in uranium dioxide in the range from 10 to 250 ?g. 1.7 This test method covers the spectrographic analysis of nuclear-grade UO2 for the 26 elements in the ranges indicated in Table 2. 1.8 For simultaneous determination of trace ele...

  17. Standard test method for the determination of uranium by ignition and the oxygen to uranium (O/U) atomic ratio of nuclear grade uranium dioxide powders and pellets

    E-Print Network [OSTI]

    American Society for Testing and Materials. Philadelphia

    2000-01-01T23:59:59.000Z

    1.1 This test method covers the determination of uranium and the oxygen to uranium atomic ratio in nuclear grade uranium dioxide powder and pellets. 1.2 This test method does not include provisions for preventing criticality accidents or requirements for health and safety. Observance of this test method does not relieve the user of the obligation to be aware of and conform to all international, national, or federal, state and local regulations pertaining to possessing, shipping, processing, or using source or special nuclear material. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1.4 This test method also is applicable to UO3 and U3O8 powder.

  18. An analysis of the impact of having uranium dioxide mixed in with plutonium dioxide

    SciTech Connect (OSTI)

    MARUSICH, R.M.

    1998-10-21T23:59:59.000Z

    An assessment was performed to show the impact on airborne release fraction, respirable fraction, dose conversion factor and dose consequences of postulated accidents at the Plutonium Finishing Plant involving uranium dioxide rather than plutonium dioxide.

  19. High temperature behavior of metallic inclusions in uranium dioxide

    SciTech Connect (OSTI)

    Yang, R.L.

    1980-08-01T23:59:59.000Z

    The object of this thesis was to construct a temperature gradient furnace to simulate the thermal conditions in the reactor fuel and to study the migration of metallic inclusions in uranium oxide under the influence of temperature gradient. No thermal migration of molybdenum and tungsten inclusions was observed under the experimental conditions. Ruthenium inclusions, however, dissolved and diffused atomically through grain boundaries in slightly reduced uranium oxide. An intermetallic compound (probably URu/sub 3/) was formed by reaction of Ru and UO/sub 2-x/. The diffusivity and solubility of ruthenium in uranium oxide were measured.

  20. Modeling thermal conductivity in UO2 with BeO additions as a function of microstructure

    E-Print Network [OSTI]

    direction. Ó 2009 Elsevier B.V. All rights reserved. 1. Introduction Uranium dioxide (UO2) is the most gradients which affect heat removal and overall reactor performance. These thermal gradients strongly

  1. Radiative heat transfer in porous uranium dioxide

    SciTech Connect (OSTI)

    Hayes, S.L. [Texas A and M Univ., College Station, TX (United States)] [Texas A and M Univ., College Station, TX (United States)

    1992-12-01T23:59:59.000Z

    Due to low thermal conductivity and high emissivity of UO{sub 2}, it has been suggested that radiative heat transfer may play a significant role in heat transfer through pores of UO{sub 2} fuel. This possibility was computationally investigated and contribution of radiative heat transfer within pores to overall heat transport in porous UO{sub 2} quantified. A repeating unit cell was developed to model approximately a porous UO{sub 2} fuel system, and the heat transfer through unit cells representing a wide variety of fuel conditions was calculated using a finite element computer program. Conduction through solid fuel matrix as wekk as pore gas, and radiative exchange at pore surface was incorporated. A variety of pore compositions were investigated: porosity, pore size, shape and orientation, temperature, and temperature gradient. Calculations were made in which pore surface radiation was both modeled and neglected. The difference between yielding the integral contribution of radiative heat transfer mechanism to overall heat transport. Results indicate that radiative component of heat transfer within pores is small for conditions representative of light water reactor fuel, typically less than 1% of total heat transport. It is much larger, however, for conditions present in liquid metal fast breeder reactor fuel; during restructuring of this fuel type early in life, the radiative heat transfer mode was shown to contribute as much as 10-20% of total heat transport in hottest regions of fuel.

  2. Fire hazards analysis for the uranium oxide (UO{sub 3}) facility

    SciTech Connect (OSTI)

    Wyatt, D.M.

    1994-12-06T23:59:59.000Z

    The Fire Hazards Analysis (FHA) documents the deactivation end-point status of the UO{sub 3} complex fire hazards, fire protection and life safety systems. This FHA has been prepared for the Uranium Oxide Facility by Westinghouse Hanford Company in accordance with the criteria established in DOE 5480.7A, Fire Protection and RLID 5480.7, Fire Protection. The purpose of the Fire Hazards Analysis is to comprehensively and quantitatively assess the risk from a fire within individual fire areas in a Department of Energy facility so as to ascertain whether the objectives stated in DOE Order 5480.7, paragraph 4 are met. Particular attention has been paid to RLID 5480.7, Section 8.3, which specifies the criteria for deactivating fire protection in decommission and demolition facilities.

  3. 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.

  4. 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.

  5. Advanced Proliferation Resistant, Lower Cost, Uranium-Thorium Dioxide Fuels for Light Water Reactors (Progress report for work through June 2002, 12th quarterly report)

    SciTech Connect (OSTI)

    Mac Donald, Philip Elsworth

    2002-09-01T23:59:59.000Z

    The overall objective of this NERI project is to evaluate the potential advantages and disadvantages of an optimized thorium-uranium dioxide (ThO2/UO2) fuel design for light water reactors (LWRs). The project is led by the Idaho National Engineering and Environmental Laboratory (INEEL), with the collaboration of three universities, the University of Florida, Massachusetts Institute of Technology (MIT), and Purdue University; Argonne National Laboratory; and all of the Pressurized Water Reactor (PWR) fuel vendors in the United States (Framatome, Siemens, and Westinghouse). In addition, a number of researchers at the Korean Atomic Energy Research Institute and Professor Kwangheon Park at Kyunghee University are active collaborators with Korean Ministry of Science and Technology funding. The project has been organized into five tasks: · Task 1 consists of fuel cycle neutronics and economics analysis to determine the economic viability of various ThO2/UO2 fuel designs in PWRs, · Task 2 will determine whether or not ThO2/UO2 fuel can be manufactured economically, · Task 3 will evaluate the behavior of ThO2/UO2 fuel during normal, off-normal, and accident conditions and compare the results with the results of previous UO2 fuel evaluations and U.S. Nuclear Regulatory Commission (NRC) licensing standards, · Task 4 will determine the long-term stability of ThO2/UO2 high-level waste, and · Task 5 consists of the Korean work on core design, fuel performance analysis, and xenon diffusivity measurements.

  6. Standard specification for sintered (Uranium-Plutonium) dioxide pellets

    E-Print Network [OSTI]

    American Society for Testing and Materials. Philadelphia

    2001-01-01T23:59:59.000Z

    1.1 This specification covers finished sintered and ground (uranium-plutonium) dioxide pellets for use in thermal reactors. It applies to uranium-plutonium dioxide pellets containing plutonium additions up to 15 % weight. This specification may not completely cover the requirements for pellets fabricated from weapons-derived plutonium. 1.2 This specification does not include (1) provisions for preventing criticality accidents or (2) requirements for health and safety. Observance of this specification does not relieve the user of the obligation to be aware of and conform to all applicable international, federal, state, and local regulations pertaining to possessing, processing, shipping, or using source or special nuclear material. Examples of U.S. government documents are Code of Federal Regulations Title 10, Part 50Domestic Licensing of Production and Utilization Facilities; Code of Federal Regulations Title 10, Part 71Packaging and Transportation of Radioactive Material; and Code of Federal Regulations Tit...

  7. Uranium vacancy mobility at the sigma 5 symmetric tilt grain boundary in UO2

    SciTech Connect (OSTI)

    Uberuaga, Blas P. [Los Alamos National Laboratory

    2012-05-02T23:59:59.000Z

    An important consequence of the fissioning process occurring during burnup is the formation of fission products. These fission products alter the thermo-mechanical properties of the fuel. They also lead to macroscopic changes in the fuel structure, including the formation of bubbles that are connected to swelling of the fuel. Subsequent release of fission gases increase the pressure in the plenum and can cause changes in the properties of the fuel pin itself. It is thus imperative to understand how fission products, and fission gases in particular, behave within the fuel in order to predict the performance of the fuel under operating conditions. Fission gas redistribution within the fuel is governed by mass transport and the presence of sinks such as impurities, dislocations, and grain boundaries. Thus, to understand how the distribution of fission gases evolves in the fuel, we must understand the underlying transport mechanisms, tied to the concentrations and mobilities of defects within the material, and how these gases interact with microstructural features that might act as sinks. Both of these issues have been addressed in previous work under NEAMS. However, once a fission product has reached a sink, such as a grain boundary, its mobility may be different there than in the grain interior and predicting how, for example, bubbles nucleate within grain boundaries necessitates an understanding of how fission gases diffuse within boundaries. That is the goal of the present work. In this report, we describe atomic level simulations of uranium vacancy diffusion in the pressence of a {Sigma}5 symmetric tilt boundary in urania (UO{sub 2}). This boundary was chosen as it is the simplest of the boundaries we considered in previous work on segregation and serves as a starting point for understanding defect mobility at boundaries. We use a combination of molecular statics calculations and kinetic Monte Carlo (kMC) to determine how the mobility of uranium vacancies is altered at this particular grain boundary. Given that the diffusion of fission gases such as Xe are tied to the mobility of uranium vacancies, these results given insight into how fission gas mobility differs at grain boundaries compared to bulk urania.

  8. Mixed uranium dicarbide and uranium dioxide microspheres and process of making same

    DOE Patents [OSTI]

    Stinton, David P. (Knoxville, TN)

    1983-01-01T23:59:59.000Z

    Nuclear fuel microspheres are made by sintering microspheres containing uranium dioxide and uncombined carbon in a 1 mole percent carbon monoxide/99 mole percent argon atmosphere at 1550.degree. C. and then sintering the microspheres in a 3 mole percent carbon monoxide/97 mole percent argon atmosphere at the same temperature.

  9. Heavy Ion Beam in Resolution of the Critical Point Problem for Uranium and Uranium Dioxide

    E-Print Network [OSTI]

    Igor Iosilevskiy; Victor Gryaznov

    2010-05-23T23:59:59.000Z

    Important advantages of heavy ion beam (HIB) irradiation of matter are discussed in comparison with traditional sources - laser heating, electron beam, electrical discharge etc. High penetration length (~ 10 mm) is of primary importance for investigation of dense matter properties. This gives an extraordinary chance to reach the uniform heating regime when HIB irradiation is being used for thermophysical property measurements. Advantages of HIB heating of highly-dispersive samples are claimed for providing free and relatively slow quasi-isobaric heating without fast hydrodynamic expansion of heated sample. Perspective of such HIB application are revised for resolution of long-time thermophysical problems for uranium and uranium-bearing compounds (UO2). The priorities in such HIB development are stressed: preferable energy levels, beam-time duration, beam focusing, deposition of the sample etc.

  10. Surface blistering and flaking of sintered uranium dioxide samples under high dose gas implantation and annealing

    E-Print Network [OSTI]

    Boyer, Edmond

    Surface blistering and flaking of sintered uranium dioxide samples under high dose gas implantation, flaking Abstract. High helium contents will be generated within minor actinide doped uranium dioxide blankets which could be used in fourth generation reactors. In this framework, it is essential to improve

  11. THERMODYNAMIC MODEL FOR URANIUM DIOXIDE BASED NUCLEAR FUEL

    SciTech Connect (OSTI)

    Thompson, Dr. William T. [Royal Military College of Canada; Lewis, Dr. Brian J [Royal Military College of Canada; Corcoran, E. C. [Royal Military College of Canada; Kaye, Dr. Matthew H. [Royal Military College of Canada; White, S. J. [Royal Military College of Canada; Akbari, F. [Atomic Energy of Canada Limited, Chalk River Laboratories; Higgs, Jamie D. [Atomic Energy of Canada Limited, Point Lepreau; Thompson, D. M. [Praxair Inc.; Besmann, Theodore M [ORNL; Vogel, S. C. [Los Alamos National Laboratory (LANL)

    2007-01-01T23:59:59.000Z

    Many projects involving nuclear fuel rest on a quantitative understanding of the co-existing phases at various stages of burnup. Since the many fission products have considerably different abilities to chemically associate with oxygen, and the oxygen-to-metal molar ratio is slowly changing, the chemical potential of oxygen is a function of burnup. Concurrently, well-recognized small fractions of new phases such as inert gas, noble metals, zirconates, etc. also develop. To further complicate matters, the dominant UO2 fuel phase may be non-stoichiometric and most of the minor phases themselves have a variable composition dependent on temperature and possible contact with the coolant in the event of a sheathing breach. A thermodynamic fuel model to predict the phases in partially burned CANDU (CANada Deuterium Uranium) nuclear fuel containing many major fission products has been under development. The building blocks of the model are the standard Gibbs energies of formation of the many possible compounds expressed as a function of temperature. To these data are added mixing terms associated with the appearance of the component species in particular phases. In operational terms, the treatment rests on the ability to minimize the Gibbs energy in a multicomponent system, in our case using the algorithms developed by Eriksson. The model is capable of handling non-stoichiometry in the UO2 fluorite phase, dilute solution behaviour of significant solute oxides, noble metal inclusions, a second metal solid solution U(Pd-Rh-Ru)3, zirconate, molybdate, and uranate solutions as well as other minor solid phases, and volatile gaseous species.

  12. Standard test methods for analysis of sintered gadolinium oxide-uranium dioxide pellets

    E-Print Network [OSTI]

    American Society for Testing and Materials. Philadelphia

    2006-01-01T23:59:59.000Z

    1.1 These test methods cover procedures for the analysis of sintered gadolinium oxide-uranium dioxide pellets to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Section Carbon (Total) by Direct CombustionThermal Conductivity Method C1408 Test Method for Carbon (Total) in Uranium Oxide Powders and Pellets By Direct Combustion-Infrared Detection Method Chlorine and Fluorine by Pyrohydrolysis Ion-Selective Electrode Method C1502 Test Method for Determination of Total Chlorine and Fluorine in Uranium Dioxide and Gadolinium Oxide Gadolinia Content by Energy-Dispersive X-Ray Spectrometry C1456 Test Method for Determination of Uranium or Gadolinium, or Both, in Gadolinium Oxide-Uranium Oxide Pellets or by X-Ray Fluorescence (XRF) Hydrogen by Inert Gas Fusion C1457 Test Method for Determination of Total Hydrogen Content of Uranium Oxide Powders and Pellets by Carrier Gas Extraction Isotopic Uranium Composition by Multiple-Filament Surface-Ioni...

  13. Spark Plasma Sintering of W-UO2 Cermets

    SciTech Connect (OSTI)

    R. C. O'Brien; N. D. Jerred

    2013-02-01T23:59:59.000Z

    About 50 vol.% 3 um depleted uranium dioxide (UO2) powder was encapsulated within a tungsten super alloy matrix produced from sub-micron tungsten powders using the Spark Plasma Sintering (SPS) process. An additive of 25 atom-percent (at.%) rhenium was included within the tungsten matrix to improve the ductility and fracture toughness of the ceramic–metallic (cermet) matrix. Cermet fabrication to 97.9% of the theoretical cermet density was achieved by sintering at 1500 degrees C with 40 MPa of applied pressure for 20 min. The results presented are from the first known trials of W–UO2 and nuclear cermet production via SPS.

  14. Thermal Conductivity Measurement of Xe-Implanted Uranium Dioxide Thick Films using Multilayer Laser Flash Analysis

    SciTech Connect (OSTI)

    Nelson, Andrew T. [Los Alamos National Laboratory

    2012-08-30T23:59:59.000Z

    The Fuel Cycle Research and Development program's Advanced Fuels campaign is currently pursuing use of ion beam assisted deposition to produce uranium dioxide thick films containing xenon in various morphologies. To date, this technique has provided materials of interest for validation of predictive fuel performance codes and to provide insight into the behavior of xenon and other fission gasses under extreme conditions. In addition to the structural data provided by such thick films, it may be possible to couple these materials with multilayer laser flash analysis in order to measure the impact of xenon on thermal transport in uranium dioxide. A number of substrate materials (single crystal silicon carbide, molybdenum, and quartz) containing uranium dioxide films ranging from one to eight microns in thickness were evaluated using multilayer laser flash analysis in order to provide recommendations on the most promising substrates and geometries for further investigation. In general, the uranium dioxide films grown to date using ion beam assisted deposition were all found too thin for accurate measurement. Of the substrates tested, molybdenum performed the best and looks to be the best candidate for further development. Results obtained within this study suggest that the technique does possess the necessary resolution for measurement of uranium dioxide thick films, provided the films are grown in excess of fifty microns. This requirement is congruent with the material needs when viewed from a fundamental standpoint, as this length scale of material is required to adequately sample grain boundaries and possible second phases present in ceramic nuclear fuel.

  15. High Thermal Conductivity UO2-BeO Nulcear Fuel: Neutronic Performance Assessments and Overview of Fabrication

    E-Print Network [OSTI]

    Naramore, Michael J

    2010-08-03T23:59:59.000Z

    The objective of this work was to evaluate a new high conductivity nuclear fuel form. Uranium dioxide (UO2) is a very effective nuclear fuel, but it’s performance is limited by its low thermal conductivity. The fuel concept considered here is a...

  16. High Thermal Conductivity UO2-BeO Nulcear Fuel: Neutronic Performance Assessments and Overview of Fabrication 

    E-Print Network [OSTI]

    Naramore, Michael J

    2010-08-03T23:59:59.000Z

    The objective of this work was to evaluate a new high conductivity nuclear fuel form. Uranium dioxide (UO2) is a very effective nuclear fuel, but it’s performance is limited by its low thermal conductivity. The fuel concept considered here is a...

  17. The Effect Of Ion Implantation Of Selected Dopants On Some Of The Electrical Properties Of UO2

    SciTech Connect (OSTI)

    Haire, M. J.; von Roedern, R. J.; Meek, T. T.; Tesmer, J.; Wetteland, C.

    2003-02-25T23:59:59.000Z

    The United States Department of Energy (DOE) has {approx}1 billion pounds of surplus depleted uranium (i.e., uranium tails) from uranium gaseous diffusion enrichment facilities. Rather than treating this material as waste, DOE is investigating potential beneficial uses for this uranium. Of the many possible uses, uranium dioxide (UO2) has properties that make it an equal to or better than conventional photovoltaic (e.g., solar cell) materials. For example, the electronic bandgap of UO2 occurs at an efficiency equal to that of GaS and Si, and it has five radiation adsorption peaks instead of one. This paper describes the experimental work being conducted to develop urania photovoltaic devices.

  18. Comparison of Spectroscopic Data with Cluster Calculations of Plutonium, Plutonium Dioxide and Uranium Dioxide

    SciTech Connect (OSTI)

    Tobin, J G; Yu, S W; Chung, B W; Ryzhkov, M V; Mirmelstein, A

    2012-05-15T23:59:59.000Z

    Using spectroscopic data produced in the experimental investigations of bulk systems, including X-Ray Absorption Spectroscopy (XAS), Photoelectron Spectroscopy (PES) and Bremstrahlung Isochromat Spectroscopy (BIS), the theoretical results within for UO{sub 2}{sup 6}, PuO{sub 2}{sup 6} and Pu{sup 7} clusters have been evaluated. The calculations of the electronic structure of the clusters have been performed within the framework of the Relativistic Discrete-Variational Method (RDV). The comparisons between the LLNL experimental data and the Russian calculations are quite favorable. The cluster calculations may represent a new and useful avenue to address unresolved questions within the field of actinide electron structure, particularly that of Pu. Observation of the changes in the Pu electronic structure as a function of size suggests interesting implications for bulk Pu electronic structure.

  19. Final Report: Manganese Redox Mediation of UO2 Stability and Uranium Fate in the Subsurface: Molecular and Meter Scale Dynamics

    SciTech Connect (OSTI)

    Tebo, Bradley M. [OSHU; Tebo, Bradley M.

    2014-09-02T23:59:59.000Z

    One strategy to remediate U contamination in the subsurface is the immobilization of U via injection of an electron donor, e.g., acetate, which leads to stimulation of the bioreduction of U(VI), the more mobile form of U, to U(IV), the less mobile form. This process is inevitably accompanied by the sequential reductive dissolution of Mn and Fe oxides and often continuing into sulfate-reducing conditions. When these reducing zones, which accumulate U(IV), experience oxidizing conditions, reduced Fe and Mn can be reoxidized forming Fe and Mn oxides that, along with O2, can impact the stability of U(IV). The focus of our project has been to investigate (i) the effects of Mn(II) on the dissolution of UO2 under both reducing and oxidizing conditions, (ii) the oxidative dissolution of UO2 by soluble Mn(III), (iii) the fate of U once it is oxidized by MnO2 in both laboratory and field settings, and (iv) the effects of groundwater constituents on the coupled Mn(II)/U(IV) oxidation process. Additionally, studies of the interaction of Se, found at the DOE site at Rifle, CO, and Mn cycling were initiated to understand if observed seasonal fluctuations of Se and Mn are directly linked and whether any such linkages can affect the stability of U(IV).

  20. 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.

  1. 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)

  2. 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.

  3. Etching of UO{sub 2} in NF{sub 3} RF Plasma Glow Discharge

    SciTech Connect (OSTI)

    John M. Veilleux

    1999-08-01T23:59:59.000Z

    A series of room temperature, low pressure (10.8 to 40 Pa), low power (25 to 210 W) RF plasma glow discharge experiments with UO{sub 2} were conducted to demonstrate that plasma treatment is a viable method for decontaminating UO{sub 2} from stainless steel substrates. Experiments were conducted using NF{sub 3} gas to decontaminate depleted uranium dioxide from stainless-steel substrates. Depleted UO{sub 2} samples each containing 129.4 Bq were prepared from 100 microliter solutions of uranyl nitrate hexahydrate solution. The amorphous UO{sub 2} in the samples had a relatively low density of 4.8 gm/cm{sub 3}. Counting of the depleted UO{sub 2} on the substrate following plasma immersion was performed using liquid scintillation counting with alpha/beta discrimination due to the presence of confounding beta emitting daughter products, {sup 234}Th and {sup 234}Pa. The alpha emission peak from each sample was integrated using a gaussian and first order polynomial fit to improve quantification. The uncertainties in the experimental measurement of the etched material were estimated at about {+-} 2%. Results demonstrated that UO{sub 2} can be completely removed from stainless-steel substrates after several minutes processing at under 200 W. At 180 W and 32.7 Pa gas pressure, over 99% of all UO{sub 2} in the samples was removed in just 17 minutes. The initial etch rate in the experiments ranged from 0.2 to 7.4 {micro}m/min. Etching increased with the plasma absorbed power and feed gas pressure in the range of 10.8 to 40 Pa. A different pressure effect on UO{sub 2} etching was also noted below 50 W in which etching increased up to a maximum pressure, {approximately}23 Pa, then decreased with further increases in pressure.

  4. High Field Magnetization measurements of uranium dioxide single crystals (P08358- E003-PF)

    SciTech Connect (OSTI)

    K. Gofryk; N. Harrison; M. Jaime

    2014-12-01T23:59:59.000Z

    Conclusions: Our preliminary high field magnetic measurements of UO2 are consistent with a complex nature of the magnetic ordering in this material, compatible with the previously proposed non-collinear 3-k magnetic structure. Further extensive magnetic studies on well-oriented (<100 > and <111>) UO2 crystals are planned to address the puzzling behavior of UO2 in both antiferromagnetic and paramagnetic states at high fields.

  5. Assessment of structures and stabilities of defect clusters and surface energies predicted by nine interatomic potentials for UO2

    SciTech Connect (OSTI)

    Stephen A. Taller; Xian-Ming Bai

    2013-11-01T23:59:59.000Z

    The irradiation in nuclear reactors creates many point defects and defect clusters in uranium dioxide (UO2) and their evolution severely degrades the thermal and mechanical properties of the nuclear fuels. Previously many empirical interatomic potentials have been developed for modeling defect production and evolution in UO2. However, the properties of defect clusters and extended defects are usually not fitted into these potentials. In this work nine interatomic potentials for UO2 are examined by using molecular statics and molecular dynamics to assess their applicability in predicting the properties of various types of defect clusters in UO2. The binding energies and structures for these defect clusters have been evaluated for each potential. In addition, the surface energies of voids of different radii and (1 1 0) flat surfaces predicted by these potentials are also evaluated. It is found that both good agreement and significant discrepancies exist for these potentials in predicting these properties. For oxygen interstitial clusters, these potentials predict significantly different defect cluster structures and stabilities; For defect clusters consisting of both uranium and oxygen defects, the prediction is in better agreement; The surface energies predicted by these potentials have significant discrepancies, and some of them are much higher than the experimentally measured values. The results from this work can provide insight on interpreting the outcome of atomistic modeling of defect production using these potentials and may provide guidelines for choosing appropriate potential models to study problems of interest in UO2.

  6. Magnetization measurements of uranium dioxide single crystals (P08358-E002-PF)

    SciTech Connect (OSTI)

    K. Gofryk; V. Zapf; M. Jaime

    2014-12-01T23:59:59.000Z

    Conclusions Our preliminary magnetic susceptibility measurements of UO2 point to complex nature of the magnetic ordering in this material, consistent with the proposed non-collinear 3-k magnetic structure. Further extensive magnetic studies are planned to address the puzzling behavior of UO2 in both antiferromagnetic and paramagnetic states.

  7. Depleted uranium dioxide melting in cold crucible melter and production of granules from the melt for use in casks for spent nuclear fuel and radioactive wastes

    SciTech Connect (OSTI)

    Gotovchikov, V.T.; Seredenko, V.A.; Shatalov, V.V.; Mironov, B.S.; Kaplenkov, V.N.; Seredenko, A.V.; Saranchin, V.K.; Shulgin, A.S. [All-Russian Research Institute of Chemical Technology (ARRICT), Moscow (Russian Federation); Haire, M.J.; Forsberg, C.W. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

    2007-07-01T23:59:59.000Z

    This paper describes the results of a joint research program between the Russian Research Institute of Chemical Technology and Oak Ridge National Laboratory in the United States to develop new radiation shielding materials for use in the construction of casks for spent nuclear fuel (SNF) and radioactive wastes. Research and development is underway to develop SNF storage, transport, and disposal casks using shielding made with two new depleted uranium dioxide (DUO{sub 2}) materials: a DUO{sub 2}-steel cermet, and, DUCRETE with DUAGG (DUO{sub 2} aggregate). Melting the DUO{sub 2} and allowing it to freeze will produce a near 100% theoretical density product and assures that the product produces no volatile materials upon subsequent heating. Induction cold-crucible melters (ICCM) are being developed for this specific application. An ICCM is, potentially, a high throughput low-cost process. Schematics of a pilot facility were developed for the production of molten DUO{sub 2} from DU{sub 3}O{sub 8} to produce granules <1 mm in diameter in a continuous mode of operation. Thermodynamic analysis was conducted for uranium-oxygen system in the temperature range from 300 to 4000 K in various gas mediums. Temperature limits of stability for various uranium oxides were determined. Experiments on melting DUO{sub 2} were carried out in a high frequency ICCM in a cold crucible with a 120 mm in diameter. The microstructure of molten DUO{sub 2} was studied and lattice parameters were determined. It was experimentally proved, and validated by X-ray analysis, that an opportunity exists to produce molten DUO{sub 2} from mixed oxides (primarily DU{sub 3}O{sub 8}) by reduction melting in ICCM. This will allow using DU{sub 3}O{sub 8} directly to make DUO{sub 2}-a separate unit operation to produce UO{sub 2} feed material is not needed. Experiments were conducted concerning the addition of alloying components, gadolinium et al. oxides, into the DUO{sub 2} melt while in the crucible. These additives improve neutron and gamma radiation shielding and operation properties of the final solids. Cermet samples of 50 wt % DUO{sub 2} were produced. (authors)

  8. Spectroscopic Studies of the Several Isomers of UO3

    SciTech Connect (OSTI)

    Sweet, Lucas E.; Reilly, Dallas D.; Abrecht, David G.; Buck, Edgar C.; Meier, David E.; Su, Yin-Fong; Brauer, Carolyn S.; Schwantes, Jon M.; Tonkyn, Russell G.; Szecsody, James E.; Blake, Thomas A.; Johnson, Timothy J.

    2013-09-26T23:59:59.000Z

    Uranium trioxide is known to adopt seven different structural forms. While these structural forms have been well characterized using x-ray or neutron diffraction techniques, little work has been done to characterize their spectroscopic properties, particularly of the pure phases. Since the structural isomers of UO3 all have similar thermodynamic stabilities and most tend to hydrolyze under open atmospheric conditions, mixtures of UO3 phases and the hydrolysis products are common. Much effort went into isolating pure phases of UO3. Utilizing x-ray diffraction as a sample identification check, UV/Vis/NIR spectroscopic signatures of ?-UO3, ?-UO3, ?-UO3 and UO2(OH)2 products were obtained. The spectra of the pure phases can now be used to characterize typical samples of UO3, which are often mixtures of isomers.

  9. Influence of Temperature on the Corrosion of Uranium Dioxide Nuclear Fuel

    SciTech Connect (OSTI)

    Broczkowski, Michael E.; Noel, Jamie J.; Shoesmith, David W. [Chemistry, The University of Western Ontario, 1151 Richmond St., London, N6A 5B7 (Canada)

    2007-07-01T23:59:59.000Z

    The anodic dissolution of UO{sub 2} has been studied at 60 deg. C and the results compared to previous observations at 22 deg. C. The rate of oxidation / dissolution was determined electrochemically at constant potentials in the range -500 mV to 500 mV (vs. SCE). The composition of the electrochemically oxidized surface was determined by X-Ray Photoelectron Spectroscopy (XPS). The onset of oxidation (UO{sub 2} {yields} UO{sub 2+x}) occurred at approximately the same potential (-400 mV) at both temperatures. However, the conversion of U{sub V} to U{sub VI}, and hence to soluble UO{sub 2}{sup 2+}, was accelerated by temperature. This acceleration of dissolution caused the development of acidity at localized sites on the fuel surface at lower (less oxidizing) potentials ({>=} 100 mV) at 60 deg. C than at 22 deg. C ({>=} 350 mV)

  10. Strong electron correlation in UO{sub 2}{sup ?}: A photoelectron spectroscopy and relativistic quantum chemistry study

    SciTech Connect (OSTI)

    Li, Wei-Li; Jian, Tian; Lopez, Gary V.; Wang, Lai-Sheng, E-mail: lai-sheng-wang@brown.edu [Department of Chemistry, Brown University, Providence, Rhode Island 02912 (United States)] [Department of Chemistry, Brown University, Providence, Rhode Island 02912 (United States); Su, Jing [Department of Chemistry and Key Laboratory of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Tsinghua University, Beijing 100084 (China) [Department of Chemistry and Key Laboratory of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Tsinghua University, Beijing 100084 (China); Division of Nuclear Materials Science and Engineering, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China and Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Chinese Academy of Sciences, Shanghai 201800 (China); Hu, Han-Shi; Cao, Guo-Jin; Li, Jun, E-mail: junli@tsinghua.edu.cn [Department of Chemistry and Key Laboratory of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Tsinghua University, Beijing 100084 (China)] [Department of Chemistry and Key Laboratory of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Tsinghua University, Beijing 100084 (China)

    2014-03-07T23:59:59.000Z

    The electronic structures of actinide systems are extremely complicated and pose considerable challenges both experimentally and theoretically because of significant electron correlation and relativistic effects. Here we report an investigation of the electronic structure and chemical bonding of uranium dioxides, UO{sub 2}{sup ?} and UO{sub 2}, using photoelectron spectroscopy and relativistic quantum chemistry. The electron affinity of UO{sub 2} is measured to be 1.159(20) eV. Intense detachment bands are observed from the UO{sub 2}{sup ?} low-lying (7s?{sub g}){sup 2}(5f?{sub u}){sup 1} orbitals and the more deeply bound O2p-based molecular orbitals which are separated by a large energy gap from the U-based orbitals. Surprisingly, numerous weak photodetachment transitions are observed in the gap region due to extensive two-electron transitions, suggesting strong electron correlations among the (7s?{sub g}){sup 2}(5f?{sub u}){sup 1} electrons in UO{sub 2}{sup ?} and the (7s?{sub g}){sup 1}(5f?{sub u}){sup 1} electrons in UO{sub 2}. These observations are interpreted using multi-reference ab initio calculations with inclusion of spin-orbit coupling. The strong electron correlations and spin-orbit couplings generate orders-of-magnitude more detachment transitions from UO{sub 2}{sup ?} than expected on the basis of the Koopmans’ theorem. The current experimental data on UO{sub 2}{sup ?} provide a long-sought opportunity to arbitrating various relativistic quantum chemistry methods aimed at handling systems with strong electron correlations.

  11. Kinetics of laser pulse vaporization of uranium dioxide by mass spectrometry

    SciTech Connect (OSTI)

    Tsai, C.

    1981-11-01T23:59:59.000Z

    Safety analyses of nuclear reactors require knowledge of the evaporation behavior of UO/sub 2/ at temperatures well above the melting point of 3140 K. In this study, rapid transient heating of a small spot on a UO/sub 2/ specimen was accomplished by a laser pulse, which generates a surface temperature excursion. This in turn vaporizes the target surface and the gas expands into vacuum. The surface temperature transient was monitored by a fast-response automatic optical pyrometer. The maximum surface temperatures investigated range from approx. 3700 K to approx. 4300 K. A computer program was developed to simulate the laser heating process and calculate the surface temperature evolution. The effect of the uncertainties of the high temperature material properties on the calculation was included in a sensitivity study for UO/sub 2/ vaporization. The measured surface temperatures were in satisfactory agreements.

  12. Refinement in the ultrasonic velocity data and estimation of the critical parameters for molten uranium dioxide

    E-Print Network [OSTI]

    Azad, Abdul-Majeed

    accurate exper- imental measurements on the density, and heat capacity of liquid UO2 up to $8000 K density and isobaric heat capacity, much more easily than other conventional methods [3,4]. Many of state for liquid urania has also been developed which predicts a critical temperature (Tc) % 10500 K

  13. Effect of Grain Boundaries on Krypton Segregation Behavior in Irradiated Uranium Dioxide

    SciTech Connect (OSTI)

    Billy Valderrama; Lingfeng He; Hunter B. Henderson; Janne Pakarinen; Brian Jaques; Jian Gan; Darryl P. Butt; Todd R. Allen; Michele V. Manuel

    2015-01-01T23:59:59.000Z

    Fission products, such as krypton (Kr), are known to be insoluble within UO2, segregating towards grain boundaries, eventually leading to a lowering of the thermal conductivity and fuel swelling. Recent computational studies have identified that differences in grain boundary structure have a significant effect on the segregation behavior of fission products. However, experimental work supporting these simulations is lacking. Atom probe tomography was used to measure the Kr distribution across grain boundaries in UO2. Polycrystalline depleted-UO2 samples was irradiated with 0.7 and 1.8 MeV Kr-ions and annealed to 1000, 1300, and 1600°C for 1 hour to produce a Kr-bubble dominated microstructure. The results of this work indicate a strong dependence of Kr concentration as a function of grain boundary structure. Temperature also influences grain boundary chemistry with greater Kr concentration evident at higher temperatures, resulting in a reduced Kr concentration in the bulk. While Kr migration is active at elevated temperatures, no changes in grain size or texture were observed in the irradiated samples.

  14. Possible effects of UO/sub 2/ oxidation on light water reactor spent fuel performance in long-term geologic disposal

    SciTech Connect (OSTI)

    Almassy, M.Y.; Woodley, R.E.

    1982-08-01T23:59:59.000Z

    Disposal of spent nuclear fuel in a conventionally mined geologic formation is the nearest-term option for permanently isolating radionuclides from the biosphere. Because irradiated uranium dioxide (UO/sub 2/) fuel pellets retain 95 to 99% of the radionuclides generated during normal light water reactor operation, they may represent a significant barrier to radionuclide release. This document presents a technical assessment of published literature representing the current level of understanding of spent fuel characteristics and conditions that may degrade pellet integrity during a geologic disposal sequence. A significant deterioration mechanism is spent UO/sub 2/ oxidation with possible consequences identified as fission gas release, rod diameter increases, cladding breach extension, and release of solid fuel particles containing radionuclides. Areas requiring further study to support development of a comprehensive spent fuel performance prediction model are highlighted. A program and preliminary schedule to obtain the information needed to develop model correlations are also presented.

  15. Use of Savannah River Site facilities for blend down of highly enriched uranium

    SciTech Connect (OSTI)

    Bickford, W.E.; McKibben, J.M.

    1994-02-01T23:59:59.000Z

    Westinghouse Savannah River Company was asked to assess the use of existing Savannah River Site (SRS) facilities for the conversion of highly enriched uranium (HEU) to low enriched uranium (LEU). The purpose was to eliminate the weapons potential for such material. Blending HEU with existing supplies of depleted uranium (DU) would produce material with less than 5% U-235 content for use in commercial nuclear reactors. The request indicated that as much as 500 to 1,000 MT of HEU would be available for conversion over a 20-year period. Existing facilities at the SRS are capable of producing LEU in the form of uranium trioxide (UO{sub 3}) powder, uranyl nitrate [UO{sub 2}(NO{sub 3}){sub 2}] solution, or metal. Additional processing, and additional facilities, would be required to convert the LEU to uranium dioxide (UO{sub 2}) or uranium hexafluoride (UF{sub 3}), the normal inputs for commercial fuel fabrication. This study`s scope does not include the cost for new conversion facilities. However, the low estimated cost per kilogram of blending HEU to LEU in SRS facilities indicates that even with fees for any additional conversion to UO{sub 2} or UF{sub 6}, blend-down would still provide a product significantly below the spot market price for LEU from traditional enrichment services. The body of the report develops a number of possible facility/process combinations for SRS. The primary conclusion of this study is that SRS has facilities available that are capable of satisfying the goals of a national program to blend HEU to below 5% U-235. This preliminary assessment concludes that several facility/process options appear cost-effective. Finally, SRS is a secure DOE site with all requisite security and safeguard programs, personnel skills, nuclear criticality safety controls, accountability programs, and supporting infrastructure to handle large quantities of special nuclear materials (SNM).

  16. Development of an Innovative High-Thermal Conductivity UO2 Ceramic Composites Fuel Pellets with Carbon Nano-Tubes Using Spark Plasma Sintering

    SciTech Connect (OSTI)

    Subhash, Ghatu; Wu, Kuang-Hsi; Tulenko, James

    2014-03-10T23:59:59.000Z

    Uranium dioxide (UO2) is the most common fuel material in commercial nuclear power reactors. Despite its numerous advantages such as high melting point, good high-temperature stability, good chemical compatibility with cladding and coolant, and resistance to radiation, it suffers from low thermal conductivity that can result in large temperature gradients within the UO2 fuel pellet, causing it to crack and release fission gases. Thermal swelling of the pellets also limits the lifetime of UO2 fuel in the reactor. To mitigate these problems, we propose to develop novel UO2 fuel with uniformly distributed carbon nanotubes (CNTs) that can provide high-conductivity thermal pathways and can eliminate fuel cracking and fission gas release due to high temperatures. CNTs have been investigated extensively for the past decade to explore their unique physical properties and many potential applications. CNTs have high thermal conductivity (6600 W/mK for an individual single- walled CNT and >3000 W/mK for an individual multi-walled CNT) and high temperature stability up to 2800°C in vacuum and about 750°C in air. These properties make them attractive candidates in preparing nano-composites with new functional properties. The objective of the proposed research is to develop high thermal conductivity of UO2–CNT composites without affecting the neutronic property of UO2 significantly. The concept of this goal is to utilize a rapid sintering method (5–15 min) called spark plasma sintering (SPS) in which a mixture of CNTs and UO2 powder are used to make composites with different volume fractions of CNTs. Incorporation of these nanoscale materials plays a fundamentally critical role in controlling the performance and stability of UO2 fuel. We will use a novel in situ growth process to grow CNTs on UO2 particles for rapid sintering and develop UO2-CNT composites. This method is expected to provide a uniform distribution of CNTs at various volume fractions so that a high thermally conductive UO2-CNT composite is obtained with a minimal volume fraction of CNTs. The mixtures are sintered in the SPS facility at a range of temperatures, pressures, and time durations so as to identify the optimal processing conditions to obtain the desired microstructure of sintered UO2-CNT pellets. The second objective of the proposed work is to identify the optimal volume fraction of CNTs in the microstructure of the composites that provides the desired high thermal conductivity yet retaining the mechanical strength required for efficient function as a reactor fuel. We will systematically study the resulting microstructure (grain size, porosity, distribution of CNTs, etc.) obtained at various SPS processing conditions using optical microscopy, scanning electron microscopy (SEM), and transmission electron microscope (TEM). We will conduct indentation hardness measurements and uniaxial strength measurements as a function of volume fraction of CNTs to determine the mechanical strength and compare them to the properties of UO2. The fracture surfaces will be studied to determine the fracture characteristics that may relate to the observed cracking during service. Finally, we will perform thermal conductivity measurements on all the composites up to 1000° C. This study will relate the microstructure, mechanical properties, and thermal properties at various volume fractions of CNTs. The overall intent is to identify optimal processing conditions that will provide a well-consolidated compact with optimal microstructure and thermo-mechanical properties. The deliverables include: (1) fully characterized UO2-CNT composite with optimal CNT volume fraction and high thermal conductivity and (2) processing conditions for production of UO2-CNT composite pellets using SPS method.

  17. A Validation Study of Pin Heat Transfer for UO2 Fuel Based on the IFA-432 Experiments

    SciTech Connect (OSTI)

    Phillippe, Aaron M [ORNL; Clarno, Kevin T [ORNL; Banfield, James E [ORNL; Ott, Larry J [ORNL; Philip, Bobby [ORNL; Berrill, Mark A [ORNL; Sampath, Rahul S [ORNL; Allu, Srikanth [ORNL; Hamilton, Steven P [ORNL

    2014-01-01T23:59:59.000Z

    The IFA-432 (Integrated Fuel Assessment) experiments from the International Fuel Performance Experiments (IFPE) database were designed to study the effects of gap size, fuel density, and fuel densification on fuel centerline temperature in light-water-reactor fuel. An evaluation of nuclear fuel pin heat transfer in the FRAPCON-3.4 and Exnihilo codes for uranium dioxide (UO$_2$) fuel systems was performed, with a focus on the densification stage (2.2 \\unitfrac{GWd}{MT(UO$_{2}$)}). In addition, sensitivity studies were performed to evaluate the effect of the radial power shape and approximations to the geometry to account for the thermocouple hole. The analysis demonstrated excellent agreement for rods 1, 2, 3, and 5 (varying gap thicknesses and density with traditional fuel), demonstrating the accuracy of the codes and their underlying material models for traditional fuel. For rod 6, which contained unstable fuel that densified an order of magnitude more than traditional, stable fuel, the magnitude of densification was over-predicted and the temperatures were outside of the experimental uncertainty. The radial power shape within the fuel was shown to significantly impact the predicted centerline temperatures, whereas modeling the fuel at the thermocouple location as either annular or solid was relatively negligible. This has provided an initial benchmarking of the pin heat transfer capability of Exnihilo for UO$_2$ fuel with respect to a well-validated nuclear fuel performance code.

  18. Cation-Cation Interactions in [(UO2)2(OH)n](4-n) Complexes. ...

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

    and (UO2)2(OH)5- shows that the CCIs and bridging hydroxo between the dioxo-uranium units are mainly electrostatic in nature. Citation: Odoh SO, N Govind, G...

  19. PUREX/UO{sub 3} deactivation project management plan

    SciTech Connect (OSTI)

    Washenfelder, D.J.

    1993-12-01T23:59:59.000Z

    From 1955 through 1990, the Plutonium-Uranium Extraction Plant (PUREX) provided the United States Department of Energy Hanford Site with nuclear fuel reprocessing capability. It operated in sequence with the Uranium Trioxide (UO{sub 3}) Plant, which converted the PUREX liquid uranium nitrate product to solid UO{sub 3} powder. Final UO{sub 3} Plant operation ended in 1993. In December 1992, planning was initiated for the deactivation of PUREX and UO{sub 3} Plant. The objective of deactivation planning was to identify the activities needed to establish a passively safe, environmentally secure configuration at both plants, and ensure that the configuration could be retained during the post-deactivation period. The PUREX/UO{sub 3} Deactivation Project management plan represents completion of the planning efforts. It presents the deactivation approach to be used for the two plants, and the supporting technical, cost, and schedule baselines. Deactivation activities concentrate on removal, reduction, and stabilization of the radioactive and chemical materials remaining at the plants, and the shutdown of the utilities and effluents. When deactivation is completed, the two plants will be left unoccupied and locked, pending eventual decontamination and decommissioning. Deactivation is expected to cost $233.8 million, require 5 years to complete, and yield $36 million in annual surveillance and maintenance cost savings.

  20. 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.

  1. Literature information applicable to the reaction of uranium oxides with chlorine to prepare uranium tetrachloride

    SciTech Connect (OSTI)

    Haas, P.A.

    1992-02-01T23:59:59.000Z

    The reaction of uranium oxides and chlorine to prepare anhydrous uranium tetrachloride (UCl{sub 4}) are important to more economical preparation of uranium metal. The most practical reactions require carbon or carbon monoxide (CO) to give CO or carbon dioxide (CO{sub 2}) as waste gases. The chemistry of U-O-Cl compounds is very complex with valances of 3, 4, 5, and 6 and with stable oxychlorides. Literature was reviewed to collect thermochemical data, phase equilibrium information, and results of experimental studies. Calculations using thermodynamic data can identify the probable reactions, but the results are uncertain. All the U-O-Cl compounds have large free energies of formation and the calculations give uncertain small differences of large numbers. The phase diagram for UCl{sub 4}-UO{sub 2} shows a reaction to form uranium oxychloride (UOCl{sub 2}) that has a good solubility in molten UCl{sub 4}. This appears more favorable to good rates of reaction than reaction of solids and gases. There is limited information on U-O-Cl salt properties. Information on the preparation of titanium, zirconium, silicon, and thorium tetrachlorides (TiCl{sub 4}, ZrCl{sub 4}, SiCl{sub 4}, ThCl{sub 4}) by reaction of oxides with chlorine (Cl{sub 2}) and carbon has application to the preparation of UCl{sub 4}.

  2. UoS Motor Accident Report Form COMPANY DETAILS

    E-Print Network [OSTI]

    Sussex, University of

    UNIV01FL02 UoS Motor Accident Report Form COMPANY DETAILS INSURED: University of Sussex ADDRESS: LOCATION: DESCRIPTION OF HOW ACCIDENT HAPPENED: PLEASE DRAW A SKETCH OF THE ACCIDENT: #12;DRIVER DETAILS: PREVIOUS ACCIDENTS: ADDRESS: VEHICLE DETAILS DATE VEHICLE PURCHASED: MAKE/MODEL: REGISTRATION: MILEAGE

  3. High temperature redox reactions with uranium: Synthesis and characterization of Cs(UO{sub 2})Cl(SeO{sub 3}), Rb{sub 2}(UO{sub 2}){sub 3}O{sub 2}(SeO{sub 3}){sub 2}, and RbNa{sub 5}U{sub 2}(SO{sub 4}){sub 7}

    SciTech Connect (OSTI)

    Babo, Jean-Marie [Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, FL 32306-4390 (United States); Department of Civil and Environmental Engineering and Earth Sciences and Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 (United States); Albrecht-Schmitt, Thomas E., E-mail: talbrechtschmitt@gmail.com [Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, FL 32306-4390 (United States)

    2013-10-15T23:59:59.000Z

    Cs(UO{sub 2})Cl(SeO{sub 3}) (1), Rb{sub 2}(UO{sub 2}){sub 3}O{sub 2}(SeO{sub 3}){sub 3} (2), and RbNa{sub 5}U{sub 2}(SO{sub 4}){sub 7} (3) single crystals were synthesized using CsCl, RbCl, and a CuCl/NaCl eutectic mixture as fluxes, respectively. Their lattice parameters and space groups are as follows: P2{sub 1}/n (a=6.548(1) Å, b=11.052(2) Å, c=10.666(2) Å and ?=93.897(3)°), P1{sup Æ} (a=7.051(2) Å, b=7.198(2) Å, c=8.314(2) Å, ?=107.897(3)°, ?=102.687(3)° and ?=100.564(3)°) and C2/c (a=17.862(4) Å, b=6.931(1) Å, c=20.133(4) Å and ?=109.737(6)°. The small anionic building units found in these compounds are SeO{sub 3}{sup 2?} and SO{sub 4}{sup 2?} tetrahedra, oxide, and chloride. The crystal structure of the first compound is composed of [(UO{sub 2}){sub 2}Cl{sub 2}(SeO{sub 3}){sub 2}]{sup 2?} chains separated by Cs{sup +} cations. The structure of (2) is constructed from [(UO{sub 2}){sub 3}O{sub 11}]{sup 16?} chains further connected through selenite units into layers stacked perpendicularly to the [0 1 0] direction, with Rb{sup +} cations intercalating between them. The structure of compound (3) is made of uranyl sulfate layers formed by edge and vertex connections between dimeric [U{sub 2}O{sub 16}] and [SO{sub 4}] polyhedra. These layers contain unusual sulfate–metal connectivity as well as large voids. - Graphical abstract: A new family of uranyl selenites and sulfates has been prepared by high-temperature redox reactions. This compounds display new bonding motifs. Display Omitted - Highlights: • Low-dimensional Uranyl Oxoanion compounds. • Conversion of U(IV) to U(VI) at high temperatures. • Dimensional reduction by both halides and stereochemically active lone-pairs.

  4. Aquifer restoration at in-situ leach uranium mines: evidence for natural restoration processes

    SciTech Connect (OSTI)

    Deutsch, W.J.; Serne, R.J.; Bell, N.E.; Martin, W.J.

    1983-04-01T23:59:59.000Z

    Pacific Northwest Laboratory conducted experiments with aquifer sediments and leaching solution (lixiviant) from an in-situ leach uranium mine. The data from these laboratory experiments and information on the normal distribution of elements associated with roll-front uranium deposits provide evidence that natural processes can enhance restoration of aquifers affected by leach mining. Our experiments show that the concentration of uranium (U) in solution can decrease at least an order of magnitude (from 50 to less than 5 ppM U) due to reactions between the lixiviant and sediment, and that a uranium solid, possibly amorphous uranium dioxide, (UO/sub 2/), can limit the concentration of uranium in a solution in contact with reduced sediment. The concentrations of As, Se, and Mo in an oxidizing lixiviant should also decrease as a result of redox and precipitation reactions between the solution and sediment. The lixiviant concentrations of major anions (chloride and sulfate) other than carbonate were not affected by short-term (less than one week) contact with the aquifer sediments. This is also true of the total dissolved solids level of the solution. Consequently, we recommend that these solution parameters be used as indicators of an excursion of leaching solution from the leach field. Our experiments have shown that natural aquifer processes can affect the solution concentration of certain constituents. This effect should be considered when guidelines for aquifer restoration are established.

  5. THE ELECTRON AFFINITY OF UO E.B. Rudnyi, E.A. Kaibicheva, L.N. Sidorov

    E-Print Network [OSTI]

    Rudnyi, Evgenii B.

    THE ELECTRON AFFINITY OF UO 3 * E.B. Rudnyi, E.A. Kaibicheva, L.N. Sidorov Department of Chemistry keywords - negative ions, uranium oxide, electron affinity, ion - molecule equilibria, high temperature stronger than fluorides. The uranium oxide lies aside from other molecules in -1 table 1. High electron

  6. Depleted uranium dioxide melting in cold crucible melter and production of granules from the melt for use in casks for spent nuclear fuel and radioactive wastes

    SciTech Connect (OSTI)

    Gotovchikov, Vitaly; Seredenko, V.A.; Shatalov, V.V.; Mironov, B.S.; Kaplenkov, V.N.; Seredenko, A.V.; Saranchin, V.K.; Shulgin, A.S.; Kalmakov, Danila [All-Russian Research Institute of Chemical Technology (ARRICT), Kashirskoe Shosse 33, Moscow 115230 (Russian Federation); Haire, M.J.; Forsberg, C.W. [Oak Ridge National Laboratory - ORNL, 1 Bethel Valley Rd, Oak Ridge, TN 37830 (United States)

    2007-07-01T23:59:59.000Z

    Available in abstract form only. Full text of publication follows: This paper describes the results of joint research program of Russian Research Institute of Chemical Technology and Oak Ridge National Laboratory to develop new materials for build spent nuclear fuel (SNF) storage, transport, and disposal casks using shielding made with depleted uranium dioxide (DUO{sub 2}) in a DUO{sub 2}-steel cermet or a DUCRETE with DUAGG (DUO{sub 2} aggregate) with selective additives in cement matrix. The preparation of DUO{sub 2} particles and aggregates for shielding could be produced from technologies that are extrapolated from the costly multi-step nuclear fuel pellet technologies. Melting the DUO{sub 2} and allowing it to freeze will produce a product near 100% theoretical density and assure that the product produces no volatile materials upon subsequent heating. Melting is a one step process that provides an opportunity to include additives in the DUO{sub 2} to modify its chemical or nuclear properties. The proposed work is directed to develop cold-wall induction heated melters (ICCM) for this specific application. Experiments on melting DUO{sub 2} were carried out in high frequency ICCM with cold crucible. It was experimentally proved an opportunity to produce molten DUO{sub 2} from mixed oxides (DU{sub 3}O{sub 8}) by reducing melting in ICCM. This will allow using DU{sub 3}O{sub 8} generated in direct conversion of depleted uranium hexafluoride as source material for melted and granulated DUO{sub 2} production. Experiments on the addition of alloying components - gadolinium oxide and others into DUO{sub 2} melt while in crucible to improve neutron and gamma radiation-shielding and operation properties of the final solids were carried out. (authors)

  7. Bioremediation of Uranium Plumes with Nano-scale

    E-Print Network [OSTI]

    Fay, Noah

    (IV) (UO2[s], uraninite) Anthropogenic Ā· 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 Ā· Leaching from

  8. 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.

  9. Fundamental study on recovery uranium oxide from HEPA filters

    SciTech Connect (OSTI)

    Izumida, T. [Hitachi Ltd., Ibaraki (Japan). Hitachi Works; Matsumoto, H.; Tsuchiya, H.; Iba, H. [Hitachi Nuclear Engineering Co., Ltd., Ibaraki (Japan); Noguchi, Y. [Radioactive Waste Management Center, Tokyo (Japan)

    1993-12-31T23:59:59.000Z

    Large numbers of spent HEPA filters are produced at uranium fuel fabrication facilities. Uranium oxide particles have been collected on these filters. Then, a spent HEPA filter treatment system was developed from the viewpoint of recovering the UO{sub 2} and minimizing the volume. The system consists of a mechanical separation process and a chemical dissolution process. This paper describes the results of fundamental experiments on recovering UO{sub 2} from HEPA filters.

  10. UO Policy Library Resource for

    E-Print Network [OSTI]

    Oregon, University of

    UO Policy Library Resource for Policy Owners To ensure University- wide consistency in the formulation, review, approval, and implementation of policies, the Policy Library has provided a resource section for policy owners. It helps answer questions such as: Is this a policy or procedure? What

  11. Gas-phase energies of actinide oxides -- an assessment of neutral and cationic monoxides and dioxides from thorium to curium

    E-Print Network [OSTI]

    Marcalo, Joaquim

    2011-01-01T23:59:59.000Z

    D. Chemical Thermodynamics of Thorium. OECD Nuclear Energyand dioxides from thorium to curium Joaquim Marēalo a,* andmonoxides and dioxides of thorium, protactinium, uranium,

  12. Americium characterization by X-ray fluorescence and absorption spectroscopy in plutonium uranium mixed oxide

    SciTech Connect (OSTI)

    Degueldre, Claude, E-mail: claude.degueldre@psi.ch; Cozzo, Cedric; Martin, Matthias; Grolimund, Daniel; Mieszczynski, Cyprian

    2013-06-01T23:59:59.000Z

    Plutonium uranium mixed oxide (MOX) fuels are currently used in nuclear reactors. The actinides in these fuels need to be analyzed after irradiation for assessing their behaviour with regard to their environment and the coolant. In this work the study of the atomic structure and next-neighbour environment of Am in the (Pu,U)O? lattice in an irradiated (60 MW d kg?¹) MOX sample was performed employing micro-X-ray fluorescence (µ-XRF) and micro-X-ray absorption fine structure (µ-XAFS) spectroscopy. The chemical bonds, valences and stoichiometry of Am (~0.66 wt%) are determined from the experimental data gained for the irradiated fuel material examined in its peripheral zone (rim) of the fuel. In the irradiated sample Am builds up as Am³? species within an [AmO?]¹³? coordination environment (e.g. >90%) and no (<10%) Am(IV) or (V) can be detected in the rim zone. The occurrence of americium dioxide is avoided by the redox buffering activity of the uranium dioxide matrix. - Graphical abstract: Americium LIII XAFS spectra recorded for the irradiated MOX sub-sample in the rim zone for a 300 ?m×300 ?m beam size area investigated over six scans of 4 h. The records remain constant during multi-scan. The analysis of the XAFS signal shows that Am is found as trivalent in the UO? matrix. This analytical work shall open the door of very challenging analysis (speciation of fission product and actinides) in irradiated nuclear fuels. - Highlights: • Americium was characterized by microX-ray absorption spectroscopy in irradiated MOX fuel. • The americium redox state as determined from XAS data of irradiated fuel material was Am(III). • In the sample, the Am³? face an AmO?¹³?coordination environment in the (Pu,U)O? matrix. • The americium dioxide is reduced by the uranium dioxide matrix.

  13. PUREX/UO{sub 3} facilities deactivation lessons learned history

    SciTech Connect (OSTI)

    Hamrick, D.G.; Gerber, M.S.

    1995-01-01T23:59:59.000Z

    The Plutonium-Uranium Extraction (PUREX) Facility operated from 1956-1972, from 1983-1988, and briefly during 1989-1990 to produce for national defense at the Hanford Site in Washington State. The Uranium Trioxide (UO{sub 3}) Facility operated at the Hanford Site from 1952-1972, 1984-1988, and briefly in 1993. Both plants were ordered to permanent shutdown by the U.S. Department of Energy (DOE) in December 1992, thus initiating their deactivation phase. Deactivation is that portion of a facility`s life cycle that occurs between operations and final decontamination and decommissioning (D&D). This document details the history of events, and the lessons learned, from the time of the PUREX Stabilization Campaign in 1989-1990, through the end of the first full fiscal year (FY) of the deactivation project (September 30, 1994).

  14. Standard test method for determination of impurities in nuclear grade uranium compounds by inductively coupled plasma mass spectrometry

    E-Print Network [OSTI]

    American Society for Testing and Materials. Philadelphia

    2010-01-01T23:59:59.000Z

    1.1 This test method covers the determination of 67 elements in uranium dioxide samples and nuclear grade uranium compounds and solutions without matrix separation by inductively coupled plasma mass spectrometry (ICP-MS). The elements are listed in Table 1. These elements can also be determined in uranyl nitrate hexahydrate (UNH), uranium hexafluoride (UF6), triuranium octoxide (U3O8) and uranium trioxide (UO3) if these compounds are treated and converted to the same uranium concentration solution. 1.2 The elements boron, sodium, silicon, phosphorus, potassium, calcium and iron can be determined using different techniques. The analyst's instrumentation will determine which procedure is chosen for the analysis. 1.3 The test method for technetium-99 is given in Annex A1. 1.4 The values stated in SI units are to be regarded as standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish ...

  15. TRIMOLECULAR REACTIONS OF URANIUM HEXAFLUORIDE WITH WATER

    SciTech Connect (OSTI)

    Westbrook, M.; Becnel, J.; Garrison, S.

    2010-02-25T23:59:59.000Z

    The hydrolysis reaction of uranium hexafluoride (UF{sub 6}) is a key step in the synthesis of uranium dioxide (UO{sub 2}) powder for nuclear fuels. Mechanisms for the hydrolysis reactions are studied here with density functional theory and the Stuttgart small-core scalar relativistic pseudopotential and associated basis set for uranium. The reaction of a single UF{sub 6} molecule with a water molecule in the gas phase has been previously predicted to proceed over a relatively sizeable barrier of 78.2 kJ {center_dot} mol{sup -1}, indicating this reaction is only feasible at elevated temperatures. Given the observed formation of a second morphology for the UO{sub 2} product coupled with the observations of rapid, spontaneous hydrolysis at ambient conditions, an alternate reaction pathway must exist. In the present work, two trimolecular hydrolysis mechanisms are studied with density functional theory: (1) the reaction between two UF{sub 6} molecules and one water molecule, and (2) the reaction of two water molecules with a single UF{sub 6} molecule. The predicted reaction of two UF{sub 6} molecules with one water molecule displays an interesting 'fluorine-shuttle' mechanism, a significant energy barrier of 69.0 kJ {center_dot} mol{sup -1} to the formation of UF{sub 5}OH, and an enthalpy of reaction ({Delta}H{sub 298}) of +17.9 kJ {center_dot} mol{sup -1}. The reaction of a single UF{sub 6} molecule with two water molecules displays a 'proton-shuttle' mechanism, and is more favorable, having a slightly lower computed energy barrier of 58.9 kJ {center_dot} mol{sup -1} and an exothermic enthalpy of reaction ({Delta}H{sub 298}) of -13.9 kJ {center_dot} mol{sup -1}. The exothermic nature of the overall UF{sub 6} + 2 {center_dot} H{sub 2}O trimolecular reaction and the lowering of the barrier height with respect to the bimolecular reaction are encouraging; however, the sizable energy barrier indicates further study of the UF{sub 6} hydrolysis reaction mechanism is warranted to resolve the remaining discrepancies between the predicted mechanisms and experimental observations.

  16. Sensitivity of UO2 Stability in a Reducing Environment on Radiolysis Model Parameters

    SciTech Connect (OSTI)

    Wittman, Richard S.; Buck, Edgar C.

    2012-09-01T23:59:59.000Z

    Results for a radiolysis model sensitivity study of radiolytically produced H2O2 are presented as they relate to Spent (or Used) Light Water Reactor uranium oxide (UO2) nuclear fuel (UNF) oxidation in a low oxygen environment. The model builds on previous reaction kinetic studies to represent the radiolytic processes occurring at the nuclear fuel surface. Hydrogen peroxide (H2O2) is the dominant oxidant for spent nuclear fuel in an O2-depleted water environment.

  17. UO

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

    success in this work will deepen our fundamental understanding of the nuclear energy materials. Background: The actinide (U, Np, Pu) oxides, nitrides, and carbides are of...

  18. Identification of secondary phases formed during unsaturated reaction of UO{sub 2} with EJ-13 water

    SciTech Connect (OSTI)

    Bates, J.K.; Tani, B.S.; Veleckis, E.

    1989-11-01T23:59:59.000Z

    A set of experiments, wherein UO{sub 2} has been contacted by dripping water, has been conducted over a period of 182.5 weeks. The experiments are being conducted to develop procedures to study spent fuel reaction under unsaturated conditions that are expected to exist over the lifetime of the proposed Yucca Mountain repository site. One half of the experiments have been terminated, while one half are ongoing. Analyses of solutions that have dripped from the reacted UO{sub 2} have been performed for all experiments, while the reacted UO{sub 2} surfaces have been examined for the terminated experiments. A pulse of uranium release from the UO{sub 2} solid, combined with the formation of schoepite on the surface of the UO{sub 2}, was observed between 39 and 96 weeks of reaction. Thereafter, the uranium release decreased and a second set of secondary phases was observed. The latter phases incorporated cations from the EJ-13 water and included boltwoodite, uranophane, sklodowskite, compreignacite, and schoepite. The experiments are continuing to monitor whether additional changes in solution chemistry or secondary phase formation occurs. 6 refs., 2 figs., 2 tabs.

  19. Identification of secondary phases formed during unsaturated reaction of UO{sub 2} with EJ-13 water

    SciTech Connect (OSTI)

    Bates, J.K.; Tani, B.S.; Veleckis, E.; Wronkiewicz, D.J. [Argonne National Lab., IL (USA)

    1990-12-31T23:59:59.000Z

    A set of experiments, wherein UO{sub 2} has been contacted by dripping water, has been conducted over a period of 182.5 weeks. The experiments are being conducted to develop procedures to study spent fuel reaction under unsaturated conditions that are expected to exist over the lifetime of the proposed Yucca Mountain repository site. One half of the experiments have been terminated, while one half are ongoing. Analyses of solutions that have dripped from the reacted UO{sub 2} have been performed for all experiments, while reacted UO{sub 2} surfaces have been examined for the terminated experiments. A pulse of uranium release from the UO{sub 2} solid, combined with the formation of schoepite on the surface of the UO{sub 2}, was observed between 39 and 96 weeks of reaction. Thereafter, the uranium release decreased and a second set of secondary phases was observed. The latter phases incorporated cations from the EJ-13 water and include boltwoodite, uranophane, sklodowskite, compreignacite, and schoepite. The experiments are continuing to monitor whether additional changes in solution chemistry or secondary phase formation occurs.

  20. 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.

  1. A Study of UO2 Grain Boundary Structure and Thermal Resistance Change under Irradiation using Molecular Dynamics Simulations

    E-Print Network [OSTI]

    Chen, Tianyi

    2013-08-02T23:59:59.000Z

    Our study is focused on the behavior of grain boundaries in uranium dioxide system under irradiation conditions. The research can be seen as two parts: the study of interaction of the grain boundary and the damage cascade, and the calculation...

  2. OXYGEN DIFFUSION IN UO2-x

    E-Print Network [OSTI]

    Kim, K.C.

    2013-01-01T23:59:59.000Z

    ~ K.C. K:i.m, "Oxygen Diffusion in Hypostoichiometricsystem for enriching uo 2 in oxygen-18 or for stoichiometry+nal of Nuclear Materials OXYGEN DIFFUSION IN U0 2 _:x K.C.

  3. 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.

  4. Dissolution characteristics of mixed UO{sub 2} powders in J-13 water under saturated conditions

    SciTech Connect (OSTI)

    Veleckis, E.; Hoh, J.C.

    1991-03-01T23:59:59.000Z

    The Yucca Mountain Project/Spent Fuel program at Argonne National Laboratory is designed to determine radionuclide release rates by exposing high-level waste to repository-relevant groundwater. To gain experience for the tests with spent fuel, a scoping experiment was conducted at room temperature to determine the uranium release rate from an unirradiated UO{sub 2} powder mixture (14.3 wt % enrichment in {sup 235}U) to J-13 water under saturated conditions. Another goal set for the experiment was to develop a method for utilizing isotope dilution techniques to determine whether the dissolution rate of UO{sub 2} matrix is in accordance with an existing kinetic model. Results of these analyses revealed unequal uranium dissolution rates from the enriched and depleted portions of the powder mixture because of undisclosed differences between them. Although the presence of this inhomogeneity has precluded the application of the kinetic model, it also provided an opportunity to elaborate on the utilization of isotope dilution data in recognizing and quantifying such conditions. Detailed listings of uranium release and solution chemistry data are presented. Other problems commonly associated with spent fuel, such as the effectiveness of filtering media, the existence of uranium concentration peaks during early stages of the leach tests, the need for concentration corrections due to water replenishments of sample volumes, and experience derived from isotope dilution data are discussed in the context of the present results. 10 refs., 5 figs., 7 tabs.

  5. Decay Heat Calculations for PWR and BWR Assemblies Fueled with Uranium and Plutonium Mixed Oxide Fuel using SCALE

    SciTech Connect (OSTI)

    Ade, Brian J [ORNL; Gauld, Ian C [ORNL

    2011-10-01T23:59:59.000Z

    In currently operating commercial nuclear power plants (NPP), there are two main types of nuclear fuel, low enriched uranium (LEU) fuel, and mixed-oxide uranium-plutonium (MOX) fuel. The LEU fuel is made of pure uranium dioxide (UO{sub 2} or UOX) and has been the fuel of choice in commercial light water reactors (LWRs) for a number of years. Naturally occurring uranium contains a mixture of different uranium isotopes, primarily, {sup 235}U and {sup 238}U. {sup 235}U is a fissile isotope, and will readily undergo a fission reaction upon interaction with a thermal neutron. {sup 235}U has an isotopic concentration of 0.71% in naturally occurring uranium. For most reactors to maintain a fission chain reaction, the natural isotopic concentration of {sup 235}U must be increased (enriched) to a level greater than 0.71%. Modern nuclear reactor fuel assemblies contain a number of fuel pins potentially having different {sup 235}U enrichments varying from {approx}2.0% to {approx}5% enriched in {sup 235}U. Currently in the United States (US), all commercial nuclear power plants use UO{sub 2} fuel. In the rest of the world, UO{sub 2} fuel is still commonly used, but MOX fuel is also used in a number of reactors. MOX fuel contains a mixture of both UO{sub 2} and PuO{sub 2}. Because the plutonium provides the fissile content of the fuel, the uranium used in MOX is either natural or depleted uranium. PuO{sub 2} is added to effectively replace the fissile content of {sup 235}U so that the level of fissile content is sufficiently high to maintain the chain reaction in an LWR. Both reactor-grade and weapons-grade plutonium contains a number of fissile and non-fissile plutonium isotopes, with the fraction of fissile and non-fissile plutonium isotopes being dependent on the source of the plutonium. While only RG plutonium is currently used in MOX, there is the possibility that WG plutonium from dismantled weapons will be used to make MOX for use in US reactors. Reactor-grade plutonium in MOX fuel is generally obtained from reprocessed irradiated nuclear fuel, whereas weapons-grade plutonium is obtained from decommissioned nuclear weapons material and thus has a different plutonium (and other actinides) concentration. Using MOX fuel instead of UOX fuel has potential impacts on the neutronic performance of the nuclear fuel and the design of the nuclear fuel must take these differences into account. Each of the plutonium sources (RG and WG) has different implications on the neutronic behavior of the fuel because each contains a different blend of plutonium nuclides. The amount of heat and the number of neutrons produced from fission of plutonium nuclides is different from fission of {sup 235}U. These differences in UOX and MOX do not end at discharge of the fuel from the reactor core - the short- and long-term storage of MOX fuel may have different requirements than UOX fuel because of the different discharged fuel decay heat characteristics. The research documented in this report compares MOX and UOX fuel during storage and disposal of the fuel by comparing decay heat rates for typical pressurized water reactor (PWR) and boiling water reactor (BWR) fuel assemblies with and without weapons-grade (WG) and reactor-grade (RG) MOX fuel.

  6. Crystal fields in UO2 - revisited

    SciTech Connect (OSTI)

    Nakotte, Heinz [Los Alamos National Laboratory; Rajatram, R [NMSU/UNIV OF N.C.; Kern, S [COLORADO STATE UNIV; Mcqueeney, R J [AMES LAB; Lander, G H [EUROPEAN COMMISIONS, JRC; Robinson, R A [BRAGG INSTITUTE

    2009-01-01T23:59:59.000Z

    We performed inelastic neutron scattering (INS) in order to re-investigate the crystal-field ground state and the level splitting in UO{sub 2}. Previous INS studies on UO{sub 2} by Amorelli et al. [Physical Review B 15, 1989, 1856] uncovered four excitations at low temperatures in the 150-180 meV range. Considering the dipole-allowed transitions, only three of these transitions could be explained by the published crystal-field model. Our INS results on a different UO{sub 2} sample revealed that the unaccounted peak at about 180 meV is a spurious one, and thus not intrinsic to UO{sub 2}. In good agreement with Amoretti's results, we corroborated that the ground-state of UO{sub 2} is the {Lambda}{sub 5} triplet, and we computed that the fourth- and six-order crystal field parameters are V{sub 4} = -116 meV and V{sub 6} = 26 meV, respectively. We also studied the INS response of the non-magnetic U{sub 0.4}Th{sub 0.6}O{sub 2}. The splitting for this thorium-doped compound is similar to the one of UO{sub 2}, which orders antiferromagnetically at low temperatures. Therefore, we can conclude that magnetic interactions only weakly perturb the energy level splitting, which is dominated by strong crystal fields.

  7. Bisphosphine dioxides

    DOE Patents [OSTI]

    Moloy, K.G.

    1990-02-20T23:59:59.000Z

    A process is described for the production of organic bisphosphine dioxides from organic bisphosphonates. The organic bisphosphonate is reacted with a Grignard reagent to give relatively high yields of the organic bisphosphine dioxide.

  8. Bisphosphine dioxides

    DOE Patents [OSTI]

    Moloy, Kenneth G. (Charleston, WV)

    1990-01-01T23:59:59.000Z

    A process for the production of organic bisphosphine dioxides from organic bisphosphonates. The organic bisphosphonate is reacted with a Grignard reagent to give relatively high yields of the organic bisphosphine dioxide.

  9. Some effects of data base variations on numerical simulations of uranium migration

    SciTech Connect (OSTI)

    Carnahan, C.L.

    1987-12-01T23:59:59.000Z

    Numerical simulations of migration of chemicals in the geosphere depend on knowledge of identities of chemical species and on values of chemical equilibrium constants supplied to the simulators. In this work, some effects of variability in assumed speciation and in equilibrium constants were examined, using migration of uranium as an example. Various simulations were done of uranium migration in systems with varying oxidation potential, pH, and mator component content. A simulation including formation of aqueous species UO/sub 2//sup 2 +/, UO/sub 2/CO/sub 3//sup 0/, UO/sub 2/(CO/sub 3/)/sub 2//sup 2 -/, UO/sub 2/(CO/sub 3/)/sub 3//sup 4 -/, (UO/sub 2/)/sub 2/CO/sub 3/(OH)/sub 3//sup -/, UO/sub 2//sup +/, U(OH)/sub 4//sup 0/, and U(OH)/sub 5//sup -/ is compared to simulation excluding formation of UO/sub 2//sup +/ and U(OH)/sub 5//sup -/. These simulations relied on older data bases, and they are compared to a further simulation using recently published data on formation of U(OH)/sub 4//sup 0/, (UO/sub 2/)/sub 2/CO/sub 3/(OH)/sub 3//sup -/, UO/sub 2/(CO/sub 3/)/sub 5//sup 5 -/, and U(CO/sub 3/)/sub 5//sup 6 -/. Significant differences in dissolved uranium concentrations are noted among the simulations. Differences are noted also in precipitation of two solids, USiO/sub 4/(c) (coffinite) and CaUO/sub 4/(c) (calcium uranate), although the solubility products of the solids were not varied in the simulations. 18 refs., 9 figs., 2 tabs.

  10. Leaching action of EJ-13 water on unirradiated UO{sub 2} surfaces under unsaturated conditions at 90{degree}C: Interim report

    SciTech Connect (OSTI)

    Wronkiewicz, D.J.; Bates, J.K.; Gerding, T.J.; Veleckis, E.; Tani, B.S.

    1991-07-01T23:59:59.000Z

    A set of experiments, based on the application of the Unsaturated Test method to the reaction of UO{sub 2} with EJ-13 water, has been conducted over a period of 182.5 weeks. One half of the experiments have been terminated, while one half are still ongoing. Solutions that have dripped from UO{sub 2} specimens have been analyzed for all experiments, while the reacted UO{sub 2} surfaces have been examined for only the terminated experiments. A pulse of uranium release from the UO{sub 2} solid, in conjunction with the formation of dehydrated schoepite on the surface of the UO{sub 2}, was observed during the 39- to 96-week period. Thereafter, the uranium release decreased and a second set of secondary phases was observed. The latter phases incorporate cations from the EJ-13 water and include boltwoodite, uranophane, sklodowskite, compreignacite, and schoepite. The experiments are being continued to monitor for additional changes in solution composition and secondary phase formation, and have now reached the 319-week period. 9 refs., 17 figs., 25 tabs.

  11. Preparation and Characterization of Uranium Oxides in Support of the K Basin Sludge Treatment Project

    SciTech Connect (OSTI)

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

    2008-07-08T23:59:59.000Z

    Uraninite (UO2) and metaschoepite (UO3·2H2O) are the uranium phases most frequently observed in K Basin sludge. Uraninite arises from the oxidation of uranium metal by anoxic water and metaschoepite arises from oxidation of uraninite by atmospheric or radiolytic oxygen. Studies of the oxidation of uraninite by oxygen to form metaschoepite were performed at 21°C and 50°C. A uranium oxide oxidation state characterization method based on spectrophotometry of the solution formed by dissolving aqueous slurries in phosphoric acid was developed to follow the extent of reaction. This method may be applied to determine uranium oxide oxidation state distribution in K Basin sludge. The uraninite produced by anoxic corrosion of uranium metal has exceedingly fine particle size (6 nm diameter), forms agglomerates, and has the formula UO2.004±0.007; i.e., is practically stoichiometric UO2. The metaschoepite particles are flatter and wider when prepared at 21°C than the particles prepared at 50°C. These particles are much smaller than the metaschoepite observed in prolonged exposure of actual K Basin sludge to warm moist oxidizing conditions. The uraninite produced by anoxic uranium metal corrosion and the metaschoepite produced by reaction of uraninite aqueous slurries with oxygen may be used in engineering and process development testing. A rapid alternative method to determine uranium metal concentrations in sludge also was identified.

  12. Surface Decontamination of System Components in Uranium Conversion Plant at KAERI

    SciTech Connect (OSTI)

    Choi, W. K.; Kim, K. N.; Won, H. J.; Jung, C. H.; Oh, W. Z.

    2003-02-25T23:59:59.000Z

    A chemical decontamination process using nitric acid solution was selected as in-situ technology for recycle or release with authorization of a large amount of metallic waste including process system components such as tanks, piping, etc., which is generated by dismantling a retired uranium conversion plant at Korea Atomic Energy Research Institute (KAERI). The applicability of nitric acid solution for surface decontamination of metallic wastes contaminated with uranium compounds was evaluated through the basic research on the dissolution of UO2 and ammonium uranyl carbonate (AUC) powder. Decontamination performance was verified by using the specimens contaminated with such uranium compounds as UO2 and AUC taken from the uranium conversion plant. Dissolution rate of UO2 powder is notably enhanced by the addition of H2O2 as an oxidant even in the condition of a low concentration of nitric acid and low temperature compared with those in a nitric acid solution without H2O2. AUC powders dissolve easily in nitric acid solutions until the solution pH attains about 2.5 {approx} 3. Above that solution pH, however, the uranium concentration in the solution is lowered drastically by precipitation as a form of U3(NH3)4O9 . 5H2O. Decontamination performance tests for the specimens contaminated with UO2 and AUC were quite successful with the application of decontamination conditions obtained through the basic studies on the dissolution of UO2 and AUC powders.

  13. Dissolution Behaviour of UO{sub 2} in Anoxic Conditions: Comparison of Ca-Bentonite and Boom Clay

    SciTech Connect (OSTI)

    Mennecart, Thierry; Cachoir, Christelle; Lemmens, Karel [SCK-CEN, Boeretang 200, MOL, 2400 (Belgium)

    2007-07-01T23:59:59.000Z

    In order to determine in how far the clay properties influence the dissolution of spent fuel, experiments were carried out with depleted UO{sub 2} in the presence of either compacted dry Ca-bentonite with Boom Clay groundwater (KB-BCW) or compacted dry Boom Clay with Boom Clay groundwater (BC-BCW). The leach tests were performed at 25 deg. C in anoxic atmosphere for 2 years. The U concentrations in the clay water were followed during these 2 years, and the amount of U in the clay was determined after 2 years in order to determine the UO{sub 2} dissolution rate. The uranium concentration after 0.45 {mu}m filtration was 50 times higher in the Boom Clay with Boom Clay water (2.0 x 10{sup -7} mol.L{sup -1}) than in Ca-bentonite with Boom Clay water (6.5 x 10{sup -9} mol.L{sup -1}), probably due to colloid formation in the Boom Clay system. Most released uranium was found in the clay. The fraction of uranium, dissolved from the UO{sub 2} pellet and found on the clay represents about 42 % of total uranium release in the system BC-BCW and more than 76 % in the system KB-BCW. The higher uranium retention of Boom Clay goes together with a higher dissolution rate. Global dissolution rates were estimated at about 2.0 x 10{sup -2} {mu}g.cm{sup -2}.d{sup -1} for the BCBCW system and 3.4 x 10{sup -3} {mu}g.cm{sup -2}.d{sup -1} for the KB-BCW system. This is not much lower than for similar tests with spent fuel, reported in literature. (authors)

  14. aqueous chlorine dioxide: Topics by E-print Network

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

    28 Standard test methods for analysis of sintered gadolinium oxide-uranium dioxide pellets CERN Preprints Summary: 1.1 These test methods cover procedures for the analysis of...

  15. Thorium dioxide: properties and nuclear applications

    SciTech Connect (OSTI)

    Belle, J.; Berman, R.M. (eds.)

    1984-01-01T23:59:59.000Z

    This is the sixth book on reactor materials published under sponsorship of the Naval Reactors Office of the United States Department of Energy, formerly the United States Atomic Energy Commission. This book presents a comprehensive compilation of the most significant properties of thorium dioxide, much like the book Uranium Dioxide: Properties and Nuclear Applications presented information on the fuel material used in the Shippingport Pressurized Water Reactor core.

  16. Investigations into the Polymorphs and Hydration Products of UO3

    SciTech Connect (OSTI)

    Sweet, Lucas E.; Buck, Edgar C.; Henager, Charles H.; Hu, Shenyang Y.; Meier, David E.; Peper, Shane M.; Schwantes, Jon M.; Su, Yin-Fong; Sams, Robert L.; Blake, Thomas A.; Johnson, Timothy J.; Kulp, Thomas J.; Sommers, Ricky L.; Sugar, Joshua D.; Chames, Jeffrey D.

    2012-04-27T23:59:59.000Z

    This work focuses on progress in gaining a better understanding of the polymorphic nature of the UO{sub 3} and UO{sub 3}-water system; one of several important materials associated with the nuclear fuel cycle. The UO{sub 3}-water system is complex and has not been fully characterized, even though these species are common throughout the fuel cycle. For example, most production schemes for UO{sub 3} result in a mixture of up to six different polymorphic phases, and small differences in these conditions will affect phase genesis that ultimately results in measureable changes to the end product. Here we summarize our efforts to better characterize the UO{sub 3}-water system with optical techniques for the purpose of developing some predictive capability of estimating process history and utility, e.g. for polymorphic phases of unknown origin. Specifically, we have investigated three industrially relevant production pathways of UO{sub 3} and discovered a previously unknown low temperature route to {beta}-UO{sub 3}. Powder x-ray diffraction and optical spectroscopies were utilized in our characterization of the UO{sub 3}-water system. Pure phases of UO{sub 3}, its hydrolysis products and starting materials were used to establish optical spectroscopic signatures for these compounds. Preliminary aging studies were conducted on the {alpha}- and {gamma}-phases of UO{sub 3}.

  17. Vibrational Spectroscopy of Mass Selected [UO2(ligand)n]2+ Complexes in the Gas Phase

    SciTech Connect (OSTI)

    Gary S. Groenewold; Anita Gianotto; Michael Vanstipdonk; Kevin C. Cossel; David T. Moore,; Nick Polfer; Jos Oomens

    2006-03-01T23:59:59.000Z

    The gas-phase infrared spectra of discrete uranyl ([UO2]2+) complexes ligated with acetone and/or acetonitrile were used to evaluate systematic trends of ligation on the position of the O=U=O stretch, and to enable rigorous comparison with the results of computational studies. Ionic uranyl complexes isolated in a Fourier transform ion cyclotron resonance mass spectrometer were fragmented via infrared multiphoton dissociation using a free electron laser scanned over the mid-IR wavelengths. The asymmetric O=U=O stretching frequency was measured at 1017 cm-1 for [UO2(CH3COCH3)2]2+, and was systematically red shifted to 1000 and 988 cm-1 by the addition of a third and fourth acetone ligands, respectively, which was consistent with more donation of electron density to the uranium center in complexes with higher coordination number. The experimental measurements were in good agreement with values generated computationally using LDA, B3LYP, and ZORA-PW91 approaches. In contrast to the uranyl frequency shifts, the carbonyl frequencies of the acetone ligands were progressively blue shifted as the number of ligands increased from 2 to 4, and approached that of free acetone. This observation was consistent with the formation of weaker noncovalent bonds between uranium and the carbonyl oxygen as the extent of ligation increases. Similar trends were observed for [UO2(CH3CN)n]2+ complexes although the magnitude of the red shift in the uranyl frequency upon addition more acetonitrile ligands was smaller than for acetone, consistent with the more modest nucleophilic nature of acetonitrile. This conclusion was amplified by the uranyl stretching frequencies measured for mixed acetone/acetonitrile complexes, which showed that substitution of one acetone for one acetonitrile produced a modest red shift of 3 to 6 cm-1.

  18. advanced doped uo2: Topics by E-print Network

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

    N. Creton1,a Physics Websites Summary: layer during the anionic oxidation of UO2 pellets induced very important mechanical stresses due to the crystallographic lattice...

  19. 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.

  20. First-principles study of defects and phase transition in UO2...

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

    defects and phase transition in UO2. First-principles study of defects and phase transition in UO2. Abstract: The electronic properties, structure and phase transformation of UO2...

  1. PUREX/UO3 Facilities deactivation lessons learned history

    SciTech Connect (OSTI)

    Gerber, M.S.

    1996-09-19T23:59:59.000Z

    Disconnecting the criticality alarm permanently in June 1996 signified that the hazards in the PUREX (plutonium-uranium extraction) plant had been so removed and reduced that criticality was no longer a credible event. Turning off the PUREX criticality alarm also marked a salient point in a historic deactivation project, 1 year before its anticipated conclusion. The PUREX/UO3 Deactivation Project began in October 1993 as a 5-year, $222.5- million project. As a result of innovations implemented during 1994 and 1995, the project schedule was shortened by over a year, with concomitant savings. In 1994, the innovations included arranging to send contaminated nitric acid from the PUREX Plant to British Nuclear Fuels, Limited (BNFL) for reuse and sending metal solutions containing plutonium and uranium from PUREX to the Hanford Site tank farms. These two steps saved the project $36.9- million. In 1995, reductions in overhead rate, work scope, and budget, along with curtailed capital equipment expenditures, reduced the cost another $25.6 million. These savings were achieved by using activity-based cost estimating and applying technical schedule enhancements. In 1996, a series of changes brought about under the general concept of ``reengineering`` reduced the cost approximately another $15 million, and moved the completion date to May 1997. With the total savings projected at about $75 million, or 33.7 percent of the originally projected cost, understanding how the changes came about, what decisions were made, and why they were made becomes important. At the same time sweeping changes in the cultural of the Hanford Site were taking place. These changes included shifting employee relations and work structures, introducing new philosophies and methods in maintaining safety and complying with regulations, using electronic technology to manage information, and, adopting new methods and bases for evaluating progress. Because these changes helped generate cost savings and were accompanied by and were an integral part of sweeping ``culture changes,`` the story of the lessons learned during the PUREX Deactivation Project are worth recounting. Foremost among the lessons is recognizing the benefits of ``right to left`` project planning. A deactivation project must start by identifying its end points, then make every task, budget, and organizational decision based on reaching those end points. Along with this key lesson is the knowledge that project planning and scheduling should be tied directly to costing, and the project status should be checked often (more often than needed to meet mandated reporting requirements) to reflect real-time work. People working on a successful project should never be guessing about its schedule or living with a paper schedule that does not represent the actual state of work. Other salient lessons were learned in the PUREX/UO3 Deactivation Project that support these guiding principles. They include recognizing the value of independent review, teamwork, and reengineering concepts; the need and value of cooperation between the DOE, its contractors, regulators, and stakeholders; and the essential nature of early and ongoing communication. Managing a successful project also requires being willing to take a fresh look at safety requirements and to apply them in a streamlined and sensible manner to deactivating facilities; draw on the enormous value of resident knowledge acquired by people over years and sometimes decades of working in old plants; and recognize the value of bringing in outside expertise for certain specialized tasks.This approach makes possible discovering the savings that can come when many creative options are pursued persistently and the wisdom of leaving some decisions to the future. The essential job of a deactivation project is to place a facility in a safe, stable, low-maintenance mode, for an interim period. Specific end points are identified to recognize and document this state. Keeping the limited objectives of the project in mind can guide decisions that reduce risks with minimal manipul

  2. NUCLEAR ISOTOPIC DILUTION OF HIGHLY ENRICHED URANIUM BY DRY BLENDING VIA THE RM-2 MILL TECHNOLOGY

    SciTech Connect (OSTI)

    Raj K. Rajamani; Sanjeeva Latchireddi; Vikas Devrani; Harappan Sethi; Roger Henry; Nate Chipman

    2003-08-01T23:59:59.000Z

    DOE has initiated numerous activities to focus on identifying material management strategies to disposition various excess fissile materials. In particular the INEEL has stored 1,700 Kg of offspec HEU at INTEC in CPP-651 vault facility. Currently, the proposed strategies for dispositioning are (a) aqueous dissolution and down blending to LEU via facilities at SRS followed by shipment of the liquid LEU to NFS for fabrication into LWR fuel for the TVA reactors and (b) dilution of the HEU to 0.9% for discard as a waste stream that would no longer have a criticality or proliferation risk without being processed through some type of enrichment system. Dispositioning this inventory as a waste stream via aqueous processing at SRS has been determined to be too costly. Thus, dry blending is the only proposed disposal process for the uranium oxide materials in the CPP-651 vault. Isotopic dilution of HEU to typically less than 20% by dry blending is the key to solving the dispositioning issue (i.e., proliferation) posed by HEU stored at INEEL. RM-2 mill is a technology developed and successfully tested for producing ultra-fine particles by dry grinding. Grinding action in RM-2 mill produces a two million-fold increase in the number of particles being blended in a centrifugal field. In a previous study, the concept of achieving complete and adequate blending and mixing (i.e., no methods were identified to easily separate and concentrate one titanium compound from the other) in remarkably short processing times was successfully tested with surrogate materials (titanium dioxide and titanium mono-oxide) with different particle sizes, hardness and densities. In the current project, the RM-2 milling technology was thoroughly tested with mixtures of natural uranium oxide (NU) and depleted uranium oxide (DU) stock to prove its performance. The effects of mill operating and design variables on the blending of NU/DU oxides were evaluated. First, NU and DU both made of the same oxide, UO{sub 3}, was used in the testing. Next, NU made up of UO{sub 3} and DU made up of UO{sub 2} was used in the test work. In every test, the blend achieved was characterized by spatial sampling of the ground product and analyzing for {sup 235}U concentration. The test work proved that these uranium oxide materials can be blended successfully. The spatial concentration was found to be uniform. Next, sintered thorium oxide pellets were used as surrogate for light water breeder reactor pellets (LWBR). To simulate LWBR pellet dispositioning, the thorium oxide pellets were first ground to a powder form and then the powder was blended with NU. In these tests also the concentration of {sup 235}U and {sup 232}Th in blended products fell within established limits proving the success of RM-2 milling technology. RM-2 milling technology is applicable to any dry radioactive waste, especially brittle solids that can be ground up and mixed with the non-radioactive stock.

  3. Evaluation of UF{sub 6}-to-UO{sub 2} conversion capability at commercial nuclear fuel fabrication facilities.

    SciTech Connect (OSTI)

    Ranek, N. L.; Monette, F. A.

    2001-06-08T23:59:59.000Z

    This report examines the capabilities of existing commercial nuclear fuel fabrication facilities to convert depleted uranium hexafluoride (UF{sub 6}) to uranium oxide (UO{sub 2}). The U.S. Department of Energy (DOE) needs this information to determine whether using such capacity to convert DOE's inventory of depleted UF{sub 6} to a more stable form is a reasonable alternative that should be considered in the site-specific environmental impact statement for construction and operation of depleted UF{sub 6} conversion facilities. Publicly available information sources were consulted to ascertain the information summarized in this report. For domestic facilities, the information summarized includes currently operating capacity to convert depleted UF{sub 6} to UO{sub 2}; transportation distances from depleted UF{sub 6} storage locations near Oak Ridge, Tennessee, Portsmouth, Ohio, and Paducah, Kentucky, to the facilities; and regulatory requirements applicable to nuclear fuel fabrication and transportation of depleted UF{sub 6}. The report concludes that the total currently operating capability of U.S. commercial nuclear fuel fabricators to convert UF{sub 6} to UO{sub 2} is approximately 5,200 metric tons of UF{sub 6} per annum (tUF{sub 6}/a). This total includes 666 tUF{sub 6}/a scheduled for shutdown by the end of 2001. However, only about 300 tUF{sub 6}/a of this capacity could be confirmed as being possibly available to DOE. The report also provides some limited descriptions of the capabilities of foreign fuel fabrication plants to convert UF{sub 6} to uranium oxide forms.

  4. OXYGEN DIFFUSION IN HYPOSTOICHIOMETRIC URANIUM DIOXIDE

    E-Print Network [OSTI]

    Kim, Kee Chul

    2010-01-01T23:59:59.000Z

    Research Division OXYGEN DIFFUSION IN HYPOSTOICHIOMETRIC11905 -DISCLAIMER - OXYGEN DIFFUSION IN HYPOSTOICHIOMETRICc o n e e n i g woroxygen self-diffusion coefficient

  5. Production of Depleted UO2Kernels for the Advanced Gas-Cooled Reactor Program for Use in TRISO Coating Development

    SciTech Connect (OSTI)

    Collins, J.L.

    2004-12-02T23:59:59.000Z

    The main objective of the Depleted UO{sub 2} Kernels Production Task at Oak Ridge National Laboratory (ORNL) was to conduct two small-scale production campaigns to produce 2 kg of UO{sub 2} kernels with diameters of 500 {+-} 20 {micro}m and 3.5 kg of UO{sub 2} kernels with diameters of 350 {+-} 10 {micro}m for the U.S. Department of Energy Advanced Fuel Cycle Initiative Program. The final acceptance requirements for the UO{sub 2} kernels are provided in the first section of this report. The kernels were prepared for use by the ORNL Metals and Ceramics Division in a development study to perfect the triisotropic (TRISO) coating process. It was important that the kernels be strong and near theoretical density, with excellent sphericity, minimal surface roughness, and no cracking. This report gives a detailed description of the production efforts and results as well as an in-depth description of the internal gelation process and its chemistry. It describes the laboratory-scale gel-forming apparatus, optimum broth formulation and operating conditions, preparation of the acid-deficient uranyl nitrate stock solution, the system used to provide uniform broth droplet formation and control, and the process of calcining and sintering UO{sub 3} {center_dot} 2H{sub 2}O microspheres to form dense UO{sub 2} kernels. The report also describes improvements and best past practices for uranium kernel formation via the internal gelation process, which utilizes hexamethylenetetramine and urea. Improvements were made in broth formulation and broth droplet formation and control that made it possible in many of the runs in the campaign to produce the desired 350 {+-} 10-{micro}m-diameter kernels, and to obtain very high yields.

  6. advanced uo2 fuel: Topics by E-print Network

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

    Last Page Topic Index 1 Determination of Gd concentration profile in UO2-Gd2O3 fuel pellets CERN Preprints Summary: A transversal mapping of the Gd concentration was measured in...

  7. Uranium-contaminated soils: Ultramicrotomy and electron beam analysis

    SciTech Connect (OSTI)

    Buck, E.C.; Dietz, N.L.; Bates, J.K.; Cunnane, J.C.

    1994-02-01T23:59:59.000Z

    Uranium-contaminated soils from the U.S. Department of Energy (DOE) Fernald Site, Ohio, have been examined by a combination of scanning electron microscopy with backscattered electron imaging (SEM/BSE) and analytical electron microscopy (AEM). The inhomogeneous distribution of particulate uranium phases in the soil required the development of a method for using ultramicrotomy to prepare transmission electron microscopy (TEM) thin sections of the SEM mounts. A water-miscible resin was selected that allowed comparison between SEM and TEM images, permitting representative sampling of the soil. Uranium was found in iron oxides, silicates (soddyite), phosphates (autunites), and fluorite (UO{sub 2}). No uranium was detected in association with phyllosilicates in the soil.

  8. Investigation of Uranium Polymorphs

    SciTech Connect (OSTI)

    Sweet, Lucas E.; Henager, Charles H.; Hu, Shenyang Y.; Johnson, Timothy J.; Meier, David E.; Peper, Shane M.; Schwantes, Jon M.

    2011-08-01T23:59:59.000Z

    The UO3-water system is complex and has not been fully characterized, even though these species are common throughout the nuclear fuel cycle. As an example, most production schemes for UO3 result in a mixture of up to six or more different polymorphic phases, and small differences in these conditions will affect phase genesis that ultimately result in measureable changes to the end product. As a result, this feature of the UO3-water system may be useful as a means for determining process history. This research effort attempts to better characterize the UO3-water system with a variety of optical techniques for the purpose of developing some predictive capability for estimating process history in polymorphic phases of unknown origin. Three commercially relevant preparation methods for the production of UO3 were explored. Previously unreported low temperature routes to ?- and ?-UO3 were discovered. Raman and fluorescence spectroscopic libraries were established for pure and mixed polymorphic forms of UO3 in addition to the common hydrolysis products of UO3. An advantage of the sensitivity of optical fluorescence microscopy over XRD has been demonstrated. Preliminary aging studies of the ? and ? forms of UO3 have been conducted. In addition, development of a 3-D phase field model used to predict phase genesis of the system was initiated. Thermodynamic and structural constants that will feed the model have been gathered from the literature for most of the UO3 polymorphic phases.

  9. Vibrational Spectroscopy of Mass-Selected [UO2(ligand)n]2+ Complexes in the Gas Phase: Comparison with Theory

    SciTech Connect (OSTI)

    Gary S. Groenewold; Anita K. Gianotto

    2006-03-01T23:59:59.000Z

    The gas-phase infrared spectra of discrete uranyl ([UO2]2+) complexes ligated with acetone and/or acetonitrile were used to evaluate systematic trends of ligation on the position of the OdUdO stretch and to enable rigorous comparison with the results of computational studies. Ionic uranyl complexes isolated in a Fourier transform ion cyclotron resonance mass spectrometer were fragmented via infrared multiphoton dissociation using a free electron laser scanned over the mid-IR wavelengths. The asymmetric OdUdO stretching frequency was measured at 1017 cm-1 for [UO2(CH3COCH3)2]2+ and was systematically red shifted to 1000 and 988 cm-1 by the addition of a third and fourth acetone ligand, respectively, which was consistent with increased donation of electron density to the uranium center in complexes with higher coordination number. The values generated computationally using LDA, B3LYP, and ZORA-PW91 were in good agreement with experimental measurements. In contrast to the uranyl frequency shifts, the carbonyl frequencies of the acetone ligands were progressively blue shifted as the number of ligands increased from two to four and approached that of free acetone. This observation was consistent with the formation of weaker noncovalent bonds between uranium and the carbonyl oxygen as the extent of ligation increases. Similar trends were observed for [UO2(CH3CN)n]2+ complexes, although the uranyl asymmetric stretching frequencies were greater than those measured for acetone complexes having equivalent coordination, which is consistent with the fact that acetonitrile is a weaker nucleophile than is acetone. This conclusion was confirmed by the uranyl stretching frequencies measured for mixed acetone/acetonitrile complexes, which showed that substitution of one acetone for one acetonitrile produced a modest red shift of 3-6 cm-1.

  10. Vibrational Spectroscopy of Mass-Selected [UO?(ligand)n]²? Complexes in the Gas Phase: Comparison with Theory

    SciTech Connect (OSTI)

    Groenewold, G. S.; Gianotto, Anita K.; Cossel, Kevin C.; Van Stipdonk, Michael J.; Moore, David T.; Polfer, Nick; Oomens, Jos; De Jong, Wibe A.; Visscher, Lucas

    2006-03-18T23:59:59.000Z

    The gas-phase infrared spectra of discrete uranyl ([UO?]²?) complexes ligated with acetone and/or acetonitrile were used to evaluate systematic trends of ligation on the position of the O=U=O stretch, and to enable rigorous comparison with the results of computational studies. Ionic uranyl complexes isolated in a Fourier transform ion cyclotron resonance mass spectrometer were fragmented via infrared multiphoton dissociation using a free electron laser scanned over the mid-IR wavelengths. The asymmetric O=U=O stretching frequency was measured at 1017 cm?¹ for [UO?(CH?COCH?)?]²? and was systematically red shifted to 1000 and 988 cm?¹ by the addition of a third and fourth acetone ligand, respectively, which was consistent with increased donation of electron density to the uranium center in complexes with higher coordination number. The values generated computationally using LDA, B3LYP, and ZORA-PW91 were in good agreement with experimental measurements. In contrast to the uranyl frequency shifts, the carbonyl frequencies of the acetone ligands were progressively blue shifted as the number of ligands increased from 2 to 4, and approached that of free acetone. This observation was consistent with the formation of weaker noncovalent bonds between uranium and the carbonyl oxygen as the extent of ligation increases. Similar trends were observed for [UO?(CH?CN)n]²? complexes, although the magnitude of the red shift in the uranyl frequency upon addition of more acetonitrile ligands was smaller than for acetone, consistent with the more modest nucleophilic nature of acetonitrile. This conclusion was confirmed by the uranyl stretching frequencies measured for mixed acetone/acetonitrile complexes, which showed that substitution of one acetone for one acetonitrile produced a modest red shift of 3 to 6 cm?¹.

  11. 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.

  12. 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.

  13. 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.

  14. Decoding Titanium Dioxide | EMSL

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

    Decoding Titanium Dioxide Decoding Titanium Dioxide Released: December 03, 2010 Scientists advance understanding of remarkable catalyst STM images of 1-, 2-, 3-, and 4-octoxy...

  15. Motivating carbon dioxide | EMSL

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

    Motivating carbon dioxide Motivating carbon dioxide Released: April 17, 2013 Scientists show what it takes to get the potential fuel feedstock to a reactive spot on a model...

  16. Separation of uranium from technetium in recovery of spent nuclear fuel

    DOE Patents [OSTI]

    Friedman, H.A.

    1984-06-13T23:59:59.000Z

    A method for decontaminating uranium product from the Purex 5 process comprises addition of hydrazine to the product uranyl nitrate stream from the Purex process, which contains hexavalent (UO/sub 2//sup 2 +/) uranium and heptavalent technetium (TcO/sub 4/-). Technetium in the product stream is reduced and then complexed by the addition of oxalic acid (H/sub 2/C/sub 2/O/sub 4/), and the Tc-oxalate complex is readily separated from the 10 uranium by solvent extraction with 30 vol % tributyl phosphate in n-dodecane.

  17. Electronic structure and ionicity of actinide oxides from first principles L. Petit,1,2,* A. Svane,1 Z. Szotek,2 W. M. Temmerman,2 and G. M. Stocks3

    E-Print Network [OSTI]

    Svane, Axel Torstein

    . A mixture of UO2 and PuO2, where Pu is blended with either natural or depleted uranium, constitutes. INTRODUCTION Actinide oxides play a dominant role in the nuclear fuel cycle.1 For many years, uranium dioxide

  18. O and Pb isotopic analyses of uranium minerals by ion microprobe and UPb ages from the Cigar Lake deposit

    E-Print Network [OSTI]

    Fayek, Mostafa

    of Nuclear Engineering and Radiological Sciences, The University of Michigan, 2958A Cooley Building, 2355­30 Am, thus providing relatively accurate information regarding the timing of fluid interactions of migration of uranium and other radionuclides from a spent fuel repository because uraninite, UO2 + x (the

  19. Topologically identical, but geometrically isomeric layers in hydrous ?-, ?-Rb[UO{sub 2}(AsO{sub 3}OH)(AsO{sub 2}(OH){sub 2})]·H{sub 2}O and anhydrous Rb[UO{sub 2}(AsO{sub 3}OH)(AsO{sub 2}(OH){sub 2})

    SciTech Connect (OSTI)

    Yu, Na; Klepov, Vladislav V. [Forschungszentrum Jülich GmbH, Institute for Energy and Climate Research (IEK-6), 52428 Jülich (Germany); Villa, Eric M. [Department of Chemistry, Creighton University, 2500 California Plaza, Omaha NE 68178 (United States); Bosbach, Dirk [Forschungszentrum Jülich GmbH, Institute for Energy and Climate Research (IEK-6), 52428 Jülich (Germany); Suleimanov, Evgeny V. [Department of Chemistry, Lobachevsky State University of Nizhny Novgorod, 603950 Nizhny Novgorod (Russian Federation); Depmeier, Wulf [Institut für Geowissenschaften, Universität zu Kiel, 24118 Kiel (Germany); Albrecht-Schmitt, Thomas E., E-mail: albrecht-schmitt@chem.fsu.edu [Department of Chemistry and Biochemistry, Florida State University, 102 Varsity Way, Tallahassee, FL 32306-4390 (United States); Alekseev, Evgeny V., E-mail: e.alekseev@fz-juelich.de [Forschungszentrum Jülich GmbH, Institute for Energy and Climate Research (IEK-6), 52428 Jülich (Germany); Institut für Kristallographie, RWTH Aachen University, 52066 Aachen (Germany)

    2014-07-01T23:59:59.000Z

    The hydrothermal reaction of uranyl nitrate with rubidium nitrate and arsenic (III) oxide results in the formation of polymorphic ?- and ?-Rb[UO{sub 2}(AsO{sub 3}OH)(AsO{sub 2}(OH){sub 2})]·H{sub 2}O (?-, ?-RbUAs) and the anhydrous phase Rb[UO{sub 2}(AsO{sub 3}OH)(AsO{sub 2}(OH){sub 2})] (RbUAs). These phases were structurally, chemically and spectroscopically characterized. The structures of all three compounds are based upon topologically identical, but geometrically isomeric layers. The layers are linked with each other by means of the Rb cations and hydrogen bonding. Dehydration experiments demonstrate that water deintercalation from hydrous ?- and ?-RbUAs yields anhydrous RbUAs via topotactic reactions. - Graphical abstract: Three different layer geometries observed in the structures of Rb[UO{sub 2}(AsO{sub 3}OH)(AsO{sub 2}(OH){sub 2})] and ?- and ?- Rb[UO{sub 2}(AsO{sub 3}OH)(AsO{sub 2}(OH){sub 2})]·H{sub 2}O. Two different coordination environments of uranium polyhedra (types I and II) are shown schematically on the top of the figure. - Highlights: • Three new uranyl arsenates were synthesized from the hydrothermal reactions. • The phases consist of the topologically identical but geometrically different layers. • Topotactic transitions were observed in the processes of mono-hyrates dehydration.

  20. Water-Moderated and -Reflected Slabs of Uranium Oxyfluoride

    SciTech Connect (OSTI)

    Margaret A. Marshall; John D. Bess; J. Blair Briggs; Clinton Gross

    2010-09-01T23:59:59.000Z

    A series of ten experiments were conducted at the Oak Ridge National Laboratory Critical Experiment Facility in December 1955, and January 1956, in an attempt to determine critical conditions for a slab of aqueous uranium oxyfluoride (UO2F2). These experiments were recorded in an Oak Ridge Critical Experiments Logbook and results were published in a journal of the American Nuclear Society, Nuclear Science and Engineering, by J. K. Fox, L. W. Gilley, and J. H. Marable (Reference 1). The purpose of these experiments was to obtain the minimum critical thickness of an effectively infinite slab of UO2F2 solution by extrapolation of experimental data. To do this the slab thickness was varied and critical solution and water-reflector heights were measured using two different fuel solutions. Of the ten conducted experiments eight of the experiments reached critical conditions but the results of only six of the experiments were published in Reference 1. All ten experiments were evaluated from which five critical configurations were judged as acceptable criticality safety benchmarks. The total uncertainty in the acceptable benchmarks is between 0.25 and 0.33 % ?k/keff. UO2F2 fuel is also evaluated in HEU-SOL-THERM-043, HEU-SOL-THERM-011, and HEU-SOL-THERM-012, but these those evaluation reports are for large reflected and unreflected spheres. Aluminum cylinders of UO2F2 are evaluated in HEU-SOL-THERM-050.

  1. 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.

  2. UO{sub 3} plant turnover - facility description document

    SciTech Connect (OSTI)

    Clapp, D.A.

    1995-01-01T23:59:59.000Z

    This document was developed to provide a facility description for those portions of the UO{sub 3} Facility being transferred to Bechtel Hanford Company, Inc. (BHI) following completion of facility deactivation. The facility and deactivated state condition description is intended only to serve as an overview of the plant as it is being transferred to BHI.

  3. 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.

  4. 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

  5. Potential incorporation of transuranics into uranium phases

    SciTech Connect (OSTI)

    Kim, C. W.; Wronkiewicz, D. J.; Buck, E. C.

    1999-12-07T23:59:59.000Z

    The UO{sub 2} in spent nuclear fuel is unstable under moist oxidizing conditions and will be altered to uranyl oxide hydrate phases. The transuranics released during the corrosion of spent fuel may also be incorporated into the structures of secondary U{sup 6+} phases. The incorporation of radionuclides into alteration products will affect their mobility. A series of precipitation tests were conducted at either 150 or 90 C for seven days to determine the potential incorporation of Ce{sup 4+} and Nd{sup 3+} (surrogates for Pu{sup 4+} and Am{sup 3+}, respectively) into uranium phases. Ianthinite ([U{sub 2}{sup 4+}(UO{sub 2}){sub 4}O{sub 6}(OH){sub 4}(H{sub 2}O){sub 4}](H{sub 2}O){sub 5}) was produced by dissolving uranium oxyacetate in a solution containing copper acetate monohydrate as a reductant. The leachant used in these tests were doped with either 2.1 ppm cerium or 399 ppm neodymium. Inductively coupled plasma-mass spectrometer (ICP-MS) analysis of the solid phase reaction products which were dissolved in a HNO{sub 3} solution indicates that about 306 ppm Ce (K{sub d} = 146) was incorporated into ianthinite, while neodymium contents were much higher, being approximately 24,800 ppm (K{sub d} = 62). Solid phase examinations using an analytical transmission electron microscope/electron energy-loss spectrometer (AEM/EELS) indicate a uniform distribution of Nd, while Ce contents were below detection. Becquerelite (Ca[(UO{sub 2}){sub 6}O{sub 4}(OH){sub 6}]{center_dot}8H{sub 2}O) was produced by dissolving uranium oxyacetate in a solution containing calcium acetate. The leachant in these tests was doped with either 2.1 ppm cerium or 277 ppm neodymium. ICP-MS results indicate that about 33 ppm Ce (K{sub d}=16) was incorporated into becquerelite, while neodymium contents were higher, being approximately 1,300 ppm (K{sub d}=5). Homogeneous distribution of Nd in the solid phase was noted during AEM/EELS examination, and Ce contents were also below detection.

  6. 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...

  7. Nitrogen dioxide detection

    DOE Patents [OSTI]

    Sinha, Dipen N. (Los Alamos, NM); Agnew, Stephen F. (Los Alamos, NM); Christensen, William H. (Buena Park, CA)

    1993-01-01T23:59:59.000Z

    Method and apparatus for detecting the presence of gaseous nitrogen dioxide and determining the amount of gas which is present. Though polystyrene is normally an insulator, it becomes electrically conductive in the presence of nitrogen dioxide. Conductance or resistance of a polystyrene sensing element is related to the concentration of nitrogen dioxide at the sensing element.

  8. 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)

  9. FEASIBILITY STUDY OF DUPOLY TO RECYCLE DEPLETED URANIUM.

    SciTech Connect (OSTI)

    ADAMS,J.W.; LAGERAAEN,P.R.; KALB,P.D.; RUTENKROGER,S.P.

    1998-02-01T23:59:59.000Z

    DUPoly, depleted uranium (DU) powder microencapsulated in a low-density polyethylene binder, has been demonstrated as an innovative and efficient recycle product, a very durable high density material with significant commercial appeal. DUPoly was successfully prepared using uranium tetrafluoride (UF{sub 4}) ''green salt'' obtained from Fluor Daniel-Fernald, a U.S. Department of Energy reprocessing facility near Cincinnati, Ohio. Samples containing up to 90 wt% UF{sub 4} were produced using a single screw plastics extruder, with sample densities of up to 3.97 {+-} 0.08 g/cm{sup 3} measured. Compressive strength of as-prepared samples (50-90 wt% UF4 ) ranged from 1682 {+-} 116 psi (11.6 {+-} 0.8 MPa) to 3145 {+-} 57 psi (21.7 {+-} 0.4 MPa). Water immersion testing for a period of 90 days produced no visible degradation of the samples. Leach rates were low, ranging from 0.02 % (2.74 x 10{sup {minus}6} gm/gm/d) for 50 wt% UF{sub 4} samples to 0.72 % (7.98 x 10{sup {minus}5} gm/gm/d) for 90 wt% samples. Sample strength was not compromised by water immersion. DUPoly samples containing uranium trioxide (UO{sub 3}), a DU reprocessing byproduct material stockpiled at the Savannah River Site, were gamma irradiated to 1 x 10{sup 9} rad with no visible deterioration. Compressive strength increased significantly, however: up to 200% for samples with 90 wt% UO{sub 3}. Correspondingly, percent deformation (strain) at failure was decreased for all samples. Gamma attenuation data on UO{sub 3} DUPoly samples yielded mass attenuation coefficients greater than those for lead. Neutron removal coefficients were calculated and shown to correlate well with wt% of DU. Unlike gamma attenuation, both hydrogenous and nonhydrogenous materials interact to attenuate neutrons.

  10. 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.

  11. {gamma}-Radiolysis of NaCl Brine in the Presence of UO{sub 2}(s): Effects of Hydrogen and Bromide

    SciTech Connect (OSTI)

    Metz, Volker; Bohnert, Elke; Kelm, Manfred; Schild, Dieter; Kienzler, Bernhard [Institute for Radioactive Waste Disposal (FZK-INE), Forschungszentrum Karlsruhe / Research Center Karlsruhe, Helmholtz-Platz, Eggenstein-Leopoldshafen, D-76344 (Germany); Reinhardt, Juergen; Buchmeiser, Michael R. [Leibniz-Institut fuer Oberflaechenmodifizierung, IOM, Permoserstr. 15, Leipzig, D-04318 (Germany)

    2007-07-01T23:59:59.000Z

    A concentrated NaCl solution was {gamma}-irradiated in autoclaves under a pressure of 25 MPa. A set of experiments were conducted in 6 mol (kg H{sub 2}O){sup -1} NaCl solution in the presence of UO{sub 2}(s) pellets; in a second set of experiments, {gamma}-radiolysis of the NaCl brine was studied without UO{sub 2}(s). Hydrogen, oxygen and chlorate were formed as long-lived radiolysis products. Due to the high external pressure, all radiolysis products remained dissolved. H{sub 2} and O{sub 2} reached steady state concentrations in the range of 5.10{sup -3} to 6.10{sup -2} mol (kg H{sub 2}O){sup -1} corresponding to a partial gas pressure of {approx}2 to {approx}20 MPa. Radiolytic formation of hydrogen and oxygen increased with the concentration of bromide added to solution. Both, in the presence of bromide, resulting in a relatively high radiolytic yield, and in the absence of bromide surfaces of the UO{sub 2}(s) samples were oxidized, and concentration of dissolved uranium reached the solubility limit of the schoepite / NaUO{sub 2}O(OH)(cr) transition. At the end of the experiments, the pellets were covered by a surface layer of a secondary solid phase having a composition close to Na{sub 2}U{sub 2}O{sub 7}. The experimental results demonstrate that bromide counteracts an H{sub 2} inhibition effect on radiolysis gas production, even at a concentration ratio of [H{sub 2}] / [Br{sup -}] > 100. The present observations are related to the competitive reactions of OH radicals with H{sub 2}, Br{sup -} and Cl{sup -}. A similar competition of hydrogen and bromide, controlling the yield of {gamma}-radiolysis products, is expected for solutions of lower Cl{sup -} concentration. (authors)

  12. Atomistic modeling of intrinsic and radiation-enhanced fission gas (Xe) diffusion in UO2 +/- x: Implications for nuclear fuel performance modeling

    SciTech Connect (OSTI)

    Giovanni Pastore; Michael R. Tonks; Derek R. Gaston; Richard L. Williamson; David Andrs; Richard Martineau

    2014-03-01T23:59:59.000Z

    Based on density functional theory (DFT) and empirical potential calculations, the diffusivity of fission gas atoms (Xe) in UO2 nuclear fuel has been calculated for a range of non-stoichiometry (i.e. UO2x), under both out-of-pile (no irradiation) and in-pile (irradiation) conditions. This was achieved by first deriving expressions for the activation energy that account for the type of trap site that the fission gas atoms occupy, which includes the corresponding type of mobile cluster, the charge state of these defects and the chemistry acting as boundary condition. In the next step DFT calculations were used to estimate migration barriers and internal energy contributions to the thermodynamic properties and calculations based on empirical potentials were used to estimate defect formation and migration entropies (i.e. pre-exponentials). The diffusivities calculated for out-of-pile conditions as function of the UO2x nonstoichiometrywere used to validate the accuracy of the diffusion models and the DFT calculations against available experimental data. The Xe diffusivity is predicted to depend strongly on the UO2x non-stoichiometry due to a combination of changes in the preferred Xe trap site and in the concentration of uranium vacancies enabling Xe diffusion, which is consistent with experiments. After establishing the validity of the modeling approach, it was used for studying Xe diffusion under in-pile conditions, for which experimental data is very scarce. The radiation-enhanced Xe diffusivity is compared to existing empirical models. Finally, the predicted fission gas diffusion rates were implemented in the BISON fuel performance code and fission gas release from a Risų fuel rod irradiation experiment was simulated. 2014 Elsevier B.V. All rights

  13. In Situ TEM Observation of Dislocation Evolutionin Polycrystalline UO2

    SciTech Connect (OSTI)

    L. F. HE; 1 M. A. KIRK; Argonne National Laboratory; J. Gan; T. R. ALLEN

    2014-10-01T23:59:59.000Z

    In situ transmission electron microscopy observation of polycrystalline UO2 (with average grain size of about 5 lm) irradiated with Kr ions at 600C and 800C was conducted to understand the radiation-induced dislocation evolution under the influence of grain boundaries. The dislocation evolution in the grain interior of polycrystalline UO2 was similar under Kr irradiation at different ion energies and temperatures. As expected, it was characterized by the nucleation and growth of dislocation loops at low irradiation doses, followed by transformation to extended dislocation lines and tangles at high doses. For the first time, a dislocation-denuded zone was observed near a grain boundary in the 1-MeV Kr-irradiated UO2 sample at 800C. The denuded zone in the vicinity of grain boundary was not found when the irradiation temperature was at 600C. The suppression of dislocation loop formation near the boundary is likely due to the enhanced interstitial diffusion toward grain boundary at the high temperature.

  14. Measurement of the Auger parameter and Wagner plot for uranium compounds

    SciTech Connect (OSTI)

    Holliday, Kiel S.; Siekhaus, Wigbert; Nelson, Art J. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94551 (United States)

    2013-05-15T23:59:59.000Z

    In this study, the photoemission from the U 4f{sub 7/2} and 4d{sub 5/2} states and the U N{sub 6}O{sub 45}O{sub 45} and N{sub 67}O{sub 45}V x-ray excited Auger transitions were measured for a range of uranium compounds. The data are presented in Wagner plots and the Auger parameter is calculated to determine the utility of this technique in the analysis of uranium materials. It was demonstrated that the equal core-level shift assumption holds for uranium. It was therefore possible to quantify the relative relaxation energies, and uranium was found to have localized core-hole shielding. The position of compounds within the Wagner plot made it possible to infer information on bonding character and local electron density. The relative ionicity of the uranium compounds studied follows the trend UF{sub 4} > UO{sub 3} > U{sub 3}O{sub 8} > U{sub 4}O{sub 9}/U{sub 3}O{sub 7} Almost-Equal-To UO{sub 2} > URu{sub 2}Si{sub 2}.

  15. Lattice thermal conductivity of UO{sub 2} using ab-initio and classical molecular dynamics

    SciTech Connect (OSTI)

    Kim, Hyoungchul [Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); High-Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136–791 (Korea, Republic of); Kim, Moo Hwan [Division of Advanced Nuclear Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Kaviany, Massoud, E-mail: kaviany@umich.edu [Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Division of Advanced Nuclear Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)

    2014-03-28T23:59:59.000Z

    We applied the non-equilibrium ab-initio molecular dynamics and predict the lattice thermal conductivity of the pristine uranium dioxide for up to 2000?K. We also use the equilibrium classical molecular dynamics and heat-current autocorrelation decay theory to decompose the lattice thermal conductivity into acoustic and optical components. The predicted optical phonon transport is temperature independent and small, while the acoustic component follows the Slack relation and is in good agreement with the limited single-crystal experimental results. Considering the phonon grain-boundary and pore scatterings, the effective lattice thermal conductivity is reduced, and we show it is in general agreement with the sintered-powder experimental results. The charge and photon thermal conductivities are also addressed, and we find small roles for electron, surface polaron, and photon in the defect-free structures and for temperatures below 1500?K.

  16. 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.

  17. 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..

  18. 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.

  19. 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.

  20. Standard test methods for arsenic in uranium hexafluoride

    E-Print Network [OSTI]

    American Society for Testing and Materials. Philadelphia

    2005-01-01T23:59:59.000Z

    1.1 These test methods are applicable to the determination of total arsenic in uranium hexafluoride (UF6) by atomic absorption spectrometry. Two test methods are given: Test Method A—Arsine Generation-Atomic Absorption (Sections 5-10), and Test Method B—Graphite Furnace Atomic Absorption (Appendix X1). 1.2 The test methods are equivalent. The limit of detection for each test method is 0.1 ?g As/g U when using a sample containing 0.5 to 1.0 g U. Test Method B does not have the complete collection details for precision and bias data thus the method appears as an appendix. 1.3 Test Method A covers the measurement of arsenic in uranyl fluoride (UO2F2) solutions by converting arsenic to arsine and measuring the arsine vapor by flame atomic absorption spectrometry. 1.4 Test Method B utilizes a solvent extraction to remove the uranium from the UO2F2 solution prior to measurement of the arsenic by graphite furnace atomic absorption spectrometry. 1.5 Both insoluble and soluble arsenic are measured when UF6 is...

  1. Future Sulfur Dioxide Emissions

    SciTech Connect (OSTI)

    Smith, Steven J.; Pitcher, Hugh M.; Wigley, Tom M.

    2005-12-01T23:59:59.000Z

    The importance of sulfur dioxide emissions for climate change is now established, although substantial uncertainties remain. This paper presents projections for future sulfur dioxide emissions using the MiniCAM integrated assessment model. A new income-based parameterization for future sulfur dioxide emissions controls is developed based on purchasing power parity (PPP) income estimates and historical trends related to the implementation of sulfur emissions limitations. This parameterization is then used to produce sulfur dioxide emissions trajectories for the set of scenarios developed for the Special Report on Emission Scenarios (SRES). We use the SRES methodology to produce harmonized SRES scenarios using the latest version of the MiniCAM model. The implications, and requirements, for IA modeling of sulfur dioxide emissions are discussed. We find that sulfur emissions eventually decline over the next century under a wide set of assumptions. These emission reductions result from a combination of emission controls, the adoption of advanced electric technologies, and a shift away from the direct end use of coal with increasing income levels. Only under a scenario where incomes in developing regions increase slowly do global emission levels remain at close to present levels over the next century. Under a climate policy that limits emissions of carbon dioxide, sulfur dioxide emissions fall in a relatively narrow range. In all cases, the relative climatic effect of sulfur dioxide emissions decreases dramatically to a point where sulfur dioxide is only a minor component of climate forcing by the end of the century. Ecological effects of sulfur dioxide, however, could be significant in some developing regions for many decades to come.

  2. 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.

  3. Molecular dynamics simulations of grain boundary thermal resistance in UO2

    SciTech Connect (OSTI)

    Tianyi Chen; Di Chen; Bulent H. Sencer; Lin Shao

    2014-09-01T23:59:59.000Z

    By means of molecular dynamics (MD) simulations, we have calculated Kaptiza resistance of UO2 with or without radiation damage. For coincident site lattice boundaries of different configurations, the boundary thermal resistance of unirradiated UO2 can be well described by a parameter-reduced formula by using boundary energies as variables. We extended the study to defect-loaded UO2 by introducing damage cascades in close vicinity to the boundaries. Following cascade annealing and defect migrations towards grain boundaries, the boundary energy increases and so does Kaptiza resistance. The correlations between these two still follow the same formula extracted from the unirradiated UO2. The finding will benefit multi-scale modeling of UO2 thermal properties under extreme radiation conditions by combining effects from boundary configurations and damage levels.

  4. 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

  5. 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.

  6. Innovative Elution Processes for Recovering Uranium from Seawater

    SciTech Connect (OSTI)

    Wai, Chien; Tian, Guoxin; Janke, Christopher

    2014-05-29T23:59:59.000Z

    Utilizing amidoxime-based polymer sorbents for extraction of uranium from seawater has attracted considerable interest in recent years. Uranium collected in the sorbent is recovered typically by elution with an acid. One drawback of acid elution is deterioration of the sorbent which is a significant factor that limits the economic competitiveness of the amidoxime-based sorbent systems for sequestering uranium from seawater. Developing innovative elution processes to improve efficiency and to minimize loss of sorbent capacity become essential in order to make this technology economically feasible for large-scale industrial applications. This project has evaluated several elution processes including acid elution, carbonate elution, and supercritical fluid elution for recovering uranium from amidoxime-based polymer sorbents. The elution efficiency, durability and sorbent regeneration for repeated uranium adsorption- desorption cycles in simulated seawater have been studied. Spectroscopic techniques are used to evaluate chemical nature of the sorbent before and after elution. A sodium carbonate-hydrogen peroxide elution process for effective removal of uranium from amidoxime-based sorbent is developed. The cause of this sodium carbonate and hydrogen peroxide synergistic leaching of uranium from amidoxime-based sorbent is attributed to the formation of an extremely stable uranyl peroxo-carbonato complex. The efficiency of uranium elution by the carbonate-hydrogen peroxide method is comparable to that of the hydrochloric acid elution but damage to the sorbent material is much less for the former. The carbonate- hydrogen peroxide elution also does not need any elaborate step to regenerate the sorbent as those required for hydrochloric acid leaching. Several CO2-soluble ligands have been tested for extraction of uranium from the sorbent in supercritical fluid carbon dioxide. A mixture of hexafluoroacetylacetone and tri-n-butylphosphate shows the best result but uranium removal from the sorbent reaches only 80% after 10 hours of leaching. Some information regarding coordination of vanadium with amidoxime molecules and elution of vanadium from amidoxime- based sorbents is also given in the report.

  7. Fabrication of Cerium Oxide and Uranium Oxide Microspheres for Space Nuclear Power Applications

    SciTech Connect (OSTI)

    Jeffrey A. Katalenich; Michael R. Hartman; Robert C. O'Brien

    2013-02-01T23:59:59.000Z

    Cerium oxide and uranium oxide microspheres are being produced via an internal gelation sol-gel method to investigate alternative fabrication routes for space nuclear fuels. Depleted uranium and non-radioactive cerium are being utilized as surrogates for plutonium-238 (Pu-238) used in radioisotope thermoelectric generators and for enriched uranium required by nuclear thermal rockets. While current methods used to produce Pu-238 fuels at Los Alamos National Laboratory (LANL) involve the generation of fine powders that pose a respiratory hazard and have a propensity to contaminate glove boxes, the sol-gel route allows for the generation of oxide microsphere fuels through an aqueous route. The sol-gel method does not generate fine powders and may require fewer processing steps than the LANL method with less operator handling. High-quality cerium dioxide microspheres have been fabricated in the desired size range and equipment is being prepared to establish a uranium dioxide microsphere production capability.

  8. 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.

  9. 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

  10. SOLUBILITY OF URANIUM AND PLUTONIUM IN ALKALINE SAVANNAH RIVER SITE HIGH LEVEL WASTE SOLUTIONS

    SciTech Connect (OSTI)

    King, W.; Hobbs, D.; Wilmarth, B.; Edwards, T.

    2010-03-10T23:59:59.000Z

    Five actual Savannah River Site tank waste samples and three chemically-modified samples were tested to determine solubility limits for uranium and plutonium over a one year time period. Observed final uranium concentrations ranged from 7 mg U/L to 4.5 g U/L. Final plutonium concentrations ranged from 4 {micro}g Pu/L to 12 mg Pu/L. Actinide carbonate complexation is believed to result in the dramatic solubility increases observed for one sample over long time periods. Clarkeite, NaUO{sub 2}(O)OH {center_dot} H{sub 2}O, was found to be the dominant uranium solid phase in equilibrium with the waste supernate in most cases.

  11. Sulfur Dioxide Regulations (Ohio)

    Broader source: Energy.gov [DOE]

    This chapter of the law establishes that the Ohio Environmental Protection Agency provides sulfur dioxide emission limits for every county, as well as regulations for the emission, monitoring and...

  12. Dispersion of UO{sub 2}F{sub 2} aerosol and HF vapor in the operating floor during winter ventilation at the Paducah Gaseous Diffusion Plant

    SciTech Connect (OSTI)

    Kim, S.H.; Chen, N.C.J.; Taleyarkhan, R.P.; Keith, K.D.; Schmidt, R.W. [Oak Ridge National Lab., TN (United States); Carter, J.C. [J.C. Carter Associates, Inc., Knoxville, TN (United States)

    1996-12-30T23:59:59.000Z

    The gaseous diffusion process is currently employed at two plants in the US: the Paducah Gaseous Diffusion Plant and the Portsmouth Gaseous Diffusion Plant. As part of a facility-wide safety evaluation, a postulated design basis accident involving large line-rupture induced releases of uranium hexafluoride (UF{sub 6}) into the process building of a gaseous diffusion plant (GDP) is evaluated. When UF{sub 6} is released into the atmosphere, it undergoes an exothermic chemical reaction with moisture (H{sub 2}O) in the air to form vaporized hydrogen fluoride (HF) and aerosolized uranyl fluoride (UO{sub 2}F{sub 2}). These reactants disperse in the process building and transport through the building ventilation system. The ventilation system draws outside air into the process building, distributes it evenly throughout the building, and discharges it to the atmosphere at an elevated temperature. Since air is recirculated from the cell floor area to the operating floor, issues concerning in-building worker safety and evacuation need to be addressed. Therefore, the objective of this study is to evaluate the transport of HF vapor and UO{sub 2}F{sub 2} aerosols throughout the operating floor area following B-line break accident in the cell floor area.

  13. Carbon dioxide removal process

    DOE Patents [OSTI]

    Baker, Richard W.; Da Costa, Andre R.; Lokhandwala, Kaaeid A.

    2003-11-18T23:59:59.000Z

    A process and apparatus for separating carbon dioxide from gas, especially natural gas, that also contains C.sub.3+ hydrocarbons. The invention uses two or three membrane separation steps, optionally in conjunction with cooling/condensation under pressure, to yield a lighter, sweeter product natural gas stream, and/or a carbon dioxide stream of reinjection quality and/or a natural gas liquids (NGL) stream.

  14. Comprehensive Investigation of the Uranium-Zirconium Alloy System: Thermophysical Properties, Phase Characterization and Ion Implantation Effects 

    E-Print Network [OSTI]

    Ahn, Sangjoon

    2013-07-31T23:59:59.000Z

    be solved even though consensus is difficult to achieve. Fresh nuclear fuel typically starts as pure uranium dioxide, but spent nuclear fuel is an complex compound comprised of about 95 % of valuable resources, uranium and plutonium, can be recycled.../Analyzer ix TRU Transuranic element U-Zr Uranium-Zirconium U-Pu-Zr Uranium-Plutonium-Zirconium XEDS X-ray Energy Dispersive Spectroscopy XRD X-ray Diffraction WDS Wavelength Dispersive Spectroscopy ZOLZ Zeroth Order Laue Zone x TABLE OF CONTENTS...

  15. Sampling, characterization, and remote sensing of aerosols formed in the atmospheric hydrolysis of uranium hexafluoride

    SciTech Connect (OSTI)

    Bostick, W.D.; McCulla, W.H.; Pickrell, P.W.

    1984-05-01T23:59:59.000Z

    When gaseous uranium hexafluoride (UF/sub 6/) is released into the atmosphere, it rapidly reacts with ambient moisture to form an aerosol of uranyl fluoride (UO/sub 2/F/sub 2/) and hydrogen fluoride (HF). As part of our Safety Analysis program, we have performed several experimental releases of HF/sub 6/ in contained volumes in order to investigate techniques for sampling and characterizing the aerosol materials. The aggregate particle morphology and size distribution have been found to be dependent upon several conditions, including the temperature of the UF/sub 6/ at the time of its release, the relative humidity of the air into which it is released, and the elapsed time after the release. Aerosol composition and settling rate have been investigated using stationary samplers for the separate collection of UO/sub 2/F/sub 2/ and HF and via laser spectroscopic remote sensing (Mie scatter and infrared spectroscopy). 25 refs., 16 figs., 5 tabs.

  16. 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.

  17. Uranium-233 purification and conversion to stabilized ceramic grade urania for LWBR fuel fabrication (LWBR Development Program)

    SciTech Connect (OSTI)

    Lloyd, R.

    1980-10-01T23:59:59.000Z

    High purity ceramic grade urania (/sup 233/UO/sub 2/) used in manufacturing the fuel for the Light Water Breeder Reactor (LWBR) core was made from uranium-233 that was obtained by irradiating thoria under special conditions to result in not more than 10 ppM of uranium-232 in the recovered uranium-233 product. A developmental study established the operating parameters of the conversion process for transforming the uranium-233 into urania powder with the appropriate chemical and physical attributes for use in fabricating the LWBR core fuel. This developmental study included the following: (a) design of an ion exchange purification process for removing the gamma-emitting alpha-decay daughters of uranium-232, to reduce the gamma-radiation field of the uranium-233 during LWBR fuel manufacture; (b) definition of the parameters for precipitating the uranium-233 as ammonium uranate (ADU) and for reducing the ADU with hydrogen to yield a urania conversion product of the proper particle size, surface area and sinterability for use in manufacturing the LWBR fuel; (c) establishment of parameters and design of equipment for stabilizing the urania conversion product to prevent it from undergoing excessive oxidation on exposure to the air during LWBR fuel manufacturing operations; and (d) development of a procedure and a facility to reprocess the unirradiated thoria-urania fuel scrap from the LWBR core manufacturing operations to recover the uranium-233 and convert it into high purity ceramic grade urania for LWBR core fabrication.

  18. Melting characteristics of the stainless steel generated from the uranium conversion plant

    SciTech Connect (OSTI)

    Choi, W.K.; Song, P.S.; Oh, W.Z.; Jung, C.H. [Korea Atomic Energy Research Institute (Korea, Republic of); Min, B.Y. [Chungnam National University, 220 Gung-Dong, Yusung-Gu Taejon 305-764 (Korea, Republic of)

    2007-07-01T23:59:59.000Z

    The partition ratio of cerium (Ce) and uranium (U) in the ingot, slag and dust phases has been investigated for the effect of the slag type, slag concentration and basicity in an electric arc melting process. An electric arc furnace (EAF) was used to melt the stainless steel wastes, simulated by uranium oxide and the real wastes from the uranium conversion plant in Korea Atomic Energy Research Institute (KAERI). The composition of the slag former used to capture the contaminants such as uranium, cerium, and cesium during the melt decontamination process generally consisted of silica (SiO{sub 2}), calcium oxide (CaO) and aluminum oxide (Al{sub 2}O{sub 3}). Also, Calcium fluoride (CaF{sub 2} ), nickel oxide (NiO), and ferric oxide (Fe{sub 2}O{sub 3}) were added to provide an increase in the slag fluidity and oxidative potential. Cerium was used as a surrogate for the uranium because the thermochemical and physical properties of cerium are very similar to those of uranium. Cerium was removed from the ingot phase to slag phase by up to 99% in this study. The absorption ratio of cerium was increased with an increase of the amount of the slag former. And the maximum removal of cerium occurred when the basicity index of the slag former was 0.82. The natural uranium (UO{sub 2}) was partitioned from the ingot phase to the slag phase by up to 95%. The absorption of the natural uranium was considerably dependent on the basicity index of the slag former and the composition of the slag former. The optimum condition for the removal of the uranium was about 1.5 for the basicity index and 15 wt% of the slag former. According to the increase of the amount of slag former, the absorption of uranium oxide in the slag phase was linearly increased due to an increase of its capacity to capture uranium oxide within the slag phase. Through experiments with various slag formers, we verified that the slag formers containing calcium fluoride (CaF{sub 2}) and a high amount of silica were more effective for a melt decontamination of stainless steel wastes contaminated with uranium. During the melting tests with stainless steel wastes from the uranium conversion plant(UCP ) in KAERI, we found that the results of the uranium decontamination were very similar to those of the uranium oxide from the melting of stimulated metal wastes. (authors)

  19. THE HIGH TEMPERATURE BEHAVIOR OF METALLIC INCLUSIONS IN URANIUM DIOXIDE.

    E-Print Network [OSTI]

    Yang, Rosa Lu.

    2010-01-01T23:59:59.000Z

    furnace Tungsten Crucible Rhenium Foil Black Body Hole U 0 Wafer Tungsten Powders U 0 Pellet Tantalum

  20. THE HIGH TEMPERATURE BEHAVIOR OF METALLIC INCLUSIONS IN URANIUM DIOXIDE.

    E-Print Network [OSTI]

    Yang, Rosa Lu.

    2010-01-01T23:59:59.000Z

    experiment, transport of oxygen toward the cold side occurs.cold edge of the inclusion. This is analogous to the vapor transport

  1. Los Alamos probes mysteries of uranium dioxide's thermal conductivity

    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. DOE Office of Science (SC)Integrated Codes |Is YourAwardspublicexceeds wasteNew insightsplants

  2. 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).

  3. 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.

  4. INTERPRETATION OF TRACER SURFACE DIFFUSION EXPERIMENTS ON UO2 ROLES OF GAS AND SOLID TRANSPORT PROCESSES

    E-Print Network [OSTI]

    Olander, D.R.

    2013-01-01T23:59:59.000Z

    hydrogen. This extrapolation was made using Eq [2) and the values of the trans- port properties (hydrogen in the MK experiment means that the UO is probably not stoichiometric. That this transport property

  5. Project Profile: Direct Supercritical Carbon Dioxide Receiver...

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

    Direct Supercritical Carbon Dioxide Receiver Development Project Profile: Direct Supercritical Carbon Dioxide Receiver Development National Renewable Energy Laboratory logo The...

  6. Electrobiocommodities from Carbon Dioxide: Enhancing Microbial...

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

    Electrobiocommodities from Carbon Dioxide: Enhancing Microbial Electrosynthesis with Synthetic Electromicrobiology and System Design Electrobiocommodities from Carbon Dioxide:...

  7. Benchmarking of Graphite Reflected Critical Assemblies of UO2

    SciTech Connect (OSTI)

    Margaret A. Marshall; John D. Bess

    2011-11-01T23:59:59.000Z

    A series of experiments were carried out in 1963 at the Oak Ridge National Laboratory Critical Experiments Facility (ORCEF) for use in space reactor research programs. A core containing 93.2% enriched UO2 fuel rods was used in these experiments. The first part of the experimental series consisted of 253 tightly-packed fuel rods (1.27 cm triangular pitch) with graphite reflectors [1], the second part used 253 graphite-reflected fuel rods organized in a 1.506 cm triangular pitch [2], and the final part of the experimental series consisted of 253 beryllium-reflected fuel rods with a 1.506 cm triangular pitch. [3] Fission rate distribution and cadmium ratio measurements were taken for all three parts of the experimental series. Reactivity coefficient measurements were taken for various materials placed in the beryllium reflected core. The first part of this experimental series has been evaluated for inclusion in the International Reactor Physics Experiment Evaluation Project (IRPhEP) [4] and the International Criticality Safety Benchmark Evaluation Project (ICSBEP) Handbooks, [5] and is discussed below. These experiments are of interest as benchmarks because they support the validation of compact reactor designs with similar characteristics to the design parameters for a space nuclear fission surface power systems. [6

  8. 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

  9. Carbon dioxide sensor

    DOE Patents [OSTI]

    Dutta, Prabir K. (Worthington, OH); Lee, Inhee (Columbus, OH); Akbar, Sheikh A. (Hilliard, OH)

    2011-11-15T23:59:59.000Z

    The present invention generally relates to carbon dioxide (CO.sub.2) sensors. In one embodiment, the present invention relates to a carbon dioxide (CO.sub.2) sensor that incorporates lithium phosphate (Li.sub.3PO.sub.4) as an electrolyte and sensing electrode comprising a combination of lithium carbonate (Li.sub.2CO.sub.3) and barium carbonate (BaCO.sub.3). In another embodiment, the present invention relates to a carbon dioxide (CO.sub.2) sensor has a reduced sensitivity to humidity due to a sensing electrode with a layered structure of lithium carbonate and barium carbonate. In still another embodiment, the present invention relates to a method of producing carbon dioxide (CO.sub.2) sensors having lithium phosphate (Li.sub.3PO.sub.4) as an electrolyte and sensing electrode comprising a combination of lithium carbonate (Li.sub.2CO.sub.3) and barium carbonate (BaCO.sub.3).

  10. 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

  11. PUREX/UO{sub 3} facilities deactivation lessons learned: History

    SciTech Connect (OSTI)

    Gerber, M.S.

    1997-11-25T23:59:59.000Z

    In May 1997, a historic deactivation project at the PUREX (Plutonium URanium EXtraction) facility at the Hanford Site in south-central Washington State concluded its activities (Figure ES-1). The project work was finished at $78 million under its original budget of $222.5 million, and 16 months ahead of schedule. Closely watched throughout the US Department of Energy (DOE) complex and by the US Department of Defense for the value of its lessons learned, the PUREX Deactivation Project has become the national model for the safe transition of contaminated facilities to shut down status.

  12. 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

  13. 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.

  14. 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.

  15. CARBON DIOXIDE FIXATION.

    SciTech Connect (OSTI)

    FUJITA,E.

    2000-01-12T23:59:59.000Z

    Solar carbon dioxide fixation offers the possibility of a renewable source of chemicals and fuels in the future. Its realization rests on future advances in the efficiency of solar energy collection and development of suitable catalysts for CO{sub 2} conversion. Recent achievements in the efficiency of solar energy conversion and in catalysis suggest that this approach holds a great deal of promise for contributing to future needs for fuels and chemicals.

  16. 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

  17. A DualDisk File System: ext4 Mihai Budiu

    E-Print Network [OSTI]

    Budiu, Mihai

    uranium oxide, UO2 [8,4] and hexavalent uranium based fluorides, UF6 [5], oxides, CaUO4 [9] and CdUO4 [10

  18. DUSCOBS - a depleted-uranium silicate backfill for transport, storage, and disposal of spent nuclear fuel

    SciTech Connect (OSTI)

    Forsberg, C.W.; Pope, R.B.; Ashline, R.C.; DeHart, M.D.; Childs, K.W.; Tang, J.S.

    1995-11-30T23:59:59.000Z

    A Depleted Uranium Silicate COntainer Backfill System (DUSCOBS) is proposed that would use small, isotopically-depleted uranium silicate glass beads as a backfill material inside storage, transport, and repository waste packages containing spent nuclear fuel (SNF). The uranium silicate glass beads would fill all void space inside the package including the coolant channels inside SNF assemblies. Based on preliminary analysis, the following benefits have been identified. DUSCOBS improves repository waste package performance by three mechanisms. First, it reduces the radionuclide releases from SNF when water enters the waste package by creating a local uranium silicate saturated groundwater environment that suppresses (1) the dissolution and/or transformation of uranium dioxide fuel pellets and, hence, (2) the release of radionuclides incorporated into the SNF pellets. Second, the potential for long-term nuclear criticality is reduced by isotopic exchange of enriched uranium in SNF with the depleted uranium (DU) in the glass. Third, the backfill reduces radiation interactions between SNF and the local environment (package and local geology) and thus reduces generation of hydrogen, acids, and other chemicals that degrade the waste package system. In addition, the DUSCOBS improves the integrity of the package by acting as a packing material and ensures criticality control for the package during SNF storage and transport. Finally, DUSCOBS provides a potential method to dispose of significant quantities of excess DU from uranium enrichment plants at potential economic savings. DUSCOBS is a new concept. Consequently, the concept has not been optimized or demonstrated in laboratory experiments.

  19. 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.

  20. 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.

  1. Determination of Gd concentration profile in UO2-Gd2O3 fuel pellets

    E-Print Network [OSTI]

    D. Tobia; E. L. Winkler; J. Milano; A. Butera; R. Kempf; L. Bianchi; F. Kaufmann

    2014-02-28T23:59:59.000Z

    A transversal mapping of the Gd concentration was measured in UO2-Gd2O3 nuclear fuel pellets by electron paramagnetic resonance spectroscopy (EPR). The quantification was made from the comparison with a Gd2O3 reference sample. The nominal concentration in the pellets is UO2: 7.5 % Gd2O3. A concentration gradient was found, which indicates that the Gd2O3 amount diminishes towards the edges of the pellets. The concentration varies from (9.3 +/- 0.5)% in the center to (5.8 +/- 0.3)% in one of the edges. The method was found to be particularly suitable for the precise mapping of the distribution of Gd3+ ions in the UO2 matrix.

  2. Determination of Gd concentration profile in UO2-Gd2O3 fuel pellets

    E-Print Network [OSTI]

    Tobia, D; Milano, J; Butera, A; Kempf, R; Bianchi, L; Kaufmann, F

    2014-01-01T23:59:59.000Z

    A transversal mapping of the Gd concentration was measured in UO2-Gd2O3 nuclear fuel pellets by electron paramagnetic resonance spectroscopy (EPR). The quantification was made from the comparison with a Gd2O3 reference sample. The nominal concentration in the pellets is UO2: 7.5 % Gd2O3. A concentration gradient was found, which indicates that the Gd2O3 amount diminishes towards the edges of the pellets. The concentration varies from (9.3 +/- 0.5)% in the center to (5.8 +/- 0.3)% in one of the edges. The method was found to be particularly suitable for the precise mapping of the distribution of Gd3+ ions in the UO2 matrix.

  3. Criticality Safety Study of UF6and UO2F2in 8-in. Inner Diameter Piping

    SciTech Connect (OSTI)

    Elam, K.R.

    2003-10-07T23:59:59.000Z

    The purpose of this report is to provide an evaluation of the criticality safety aspects of using up to 8-in.-inner-diameter (ID) piping as part of a system to monitor the {sup 235}U enrichment in uranium hexafluoride (UF{sub 6}) gas both before and after an enrichment down-blending operation. The evaluated operation does not include the blending stage but includes only the monitors and the piping directly associated with the monitors, which are in a separate room from the blending operation. There are active controls in place to limit the enrichment of the blended UF{sub 6} to a maximum of 5 weight percent (wt%) {sup 235}U. Under normal operating conditions of temperature and pressure, the UF{sub 6} will stay in the gas phase and criticality will not be credible. The two accidents of concern are solidification of the UF{sub 6} along with some hydrofluoric acid (HF) and water or moisture ingress, which would cause the UF{sub 6} gas to react and form a hydrated uranyl fluoride (UO{sub 2}F{sub 2}) solid or solution. Of these two types of accidents, the addition of water and formation of UO{sub 2}F{sub 2} is the most reactive scenario and thus limits related to UO{sub 2}F{sub 2} will bound the limits related to UF{sub 6}. Two types of systems are included in the monitoring process. The first measures the enrichment of the approximately 90 wt% enriched UF{sub 6} before it is blended. This system uses a maximum 4-in.-(10.16-cm-) ID pipe, which is smaller than the 13.7-cm-cylinder-diameter subcritical limit for UO{sub 2}F{sub 2} solution of any enrichment as given in Table 1 of American National Standard ANSI/ANS-8.1.1 Therefore, this system poses no criticality concerns for either accident scenario. The second type of system includes two enrichment monitors for lower-enriched UF{sub 6}. One monitors the approximately 1.5 wt% enriched UF{sub 6} entering the blending process, and the second monitors the approximately 5 wt% enriched UF{sub 6} coming out of the blending process. Both use a maximum 8-in.-(20.32-cm-) ID piping, where the length of the larger ID piping is approximately 9.5 m. This diameter of piping is below the 26.6-cm-cylinder-diameter subcritical limit for 5 wt% enriched UO{sub 2}F{sub 2} solutions as given in Table 6 of ANSI/ANS-8.1. Therefore, for up to 5 wt% enriched UF{sub 6}, this piping does not present a criticality concern for either accident scenario. Calculations were performed to determine the enrichment level at which criticality could become a concern in these 8-in.-ID piping sections. Both unreflected and fully water-reflected conditions were considered.

  4. What's Next for Vanadium Dioxide?

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

    National Laboratory (ORNL) has made an important advancement in understanding a classic transition-metal oxide, vanadium dioxide, by quantifying the thermodynamic forces driving...

  5. 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...

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. Carbon Dioxide Reduction Through Urban Forestry

    E-Print Network [OSTI]

    Standiford, Richard B.

    . Retrieval Terms: urban forestry, carbon dioxide, sequestration, avoided energy The Authors E. Gregory McCarbon Dioxide Reduction Through Urban Forestry: Guidelines for Professional and Volunteer Tree; Simpson, James R. 1999. Carbon dioxide reduction through urban forestry

  11. Process for sequestering carbon dioxide and sulfur dioxide

    DOE Patents [OSTI]

    Maroto-Valer, M. Mercedes (State College, PA); Zhang, Yinzhi (State College, PA); Kuchta, Matthew E. (State College, PA); Andresen, John M. (State College, PA); Fauth, Dan J. (Pittsburgh, PA)

    2009-10-20T23:59:59.000Z

    A process for sequestering carbon dioxide, which includes reacting a silicate based material with an acid to form a suspension, and combining the suspension with carbon dioxide to create active carbonation of the silicate-based material, and thereafter producing a metal salt, silica and regenerating the acid in the liquid phase of the suspension.

  12. 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)

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Optimize carbon dioxide sequestration, enhance oil recovery

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

    Optimize carbon dioxide sequestration, enhance oil recovery Optimize carbon dioxide sequestration, enhance oil recovery The simulation provides an important approach to estimate...

  18. Case Study: Transcritical Carbon Dioxide Supermarket Refrigeration...

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

    Case Study: Transcritical Carbon Dioxide Supermarket Refrigeration Systems Case Study: Transcritical Carbon Dioxide Supermarket Refrigeration Systems This case study documents one...

  19. Carbon dioxide and climate

    SciTech Connect (OSTI)

    Not Available

    1990-10-01T23:59:59.000Z

    Scientific and public interest in greenhouse gases, climate warming, and global change virtually exploded in 1988. The Department's focused research on atmospheric CO{sub 2} contributed sound and timely scientific information to the many questions produced by the groundswell of interest and concern. Research projects summarized in this document provided the data base that made timely responses possible, and the contributions from participating scientists are genuinely appreciated. In the past year, the core CO{sub 2} research has continued to improve the scientific knowledge needed to project future atmospheric CO{sub 2} concentrations, to estimate climate sensitivity, and to assess the responses of vegetation to rising concentrations of CO{sub 2} and to climate change. The Carbon Dioxide Research Program's goal is to develop sound scientific information for policy formulation and governmental action in response to changes of atmospheric CO{sub 2}. The Program Summary describes projects funded by the Carbon Dioxide Research Program during FY 1990 and gives a brief overview of objectives, organization, and accomplishments.

  20. 12/21/2011 KWarden UO Policy Library Policy Revision and Update Guidelines

    E-Print Network [OSTI]

    Oregon, University of

    12/21/2011 ­ KWarden UO Policy Library Policy Revision and Update Guidelines Any Responsible Office, Policy Statement: Development and Management. The policy refers to two types of revisions: substantive: Development and Management, which is found in the Policy Library. Minor Revision or Update A minor revision

  1. Radiation-Induced Decomposition of U(VI) Phase to Nanocrystals of UO2

    SciTech Connect (OSTI)

    S. Utsunomiya; R.C. Ewing; L. Wang

    2005-06-13T23:59:59.000Z

    U{sup 6+}-phases are common alteration products, under oxidizing conditions, of uraninite and the UO{sub 2} in spent nuclear fuel. These U{sup 6+}-phases are subjected to a radiation field caused by the {alpha}-decay of U, or in the case of spent nuclear fuel, incorporated actinides, such as {sup 239}Pu and {sup 237}Np. In order to evaluate the effects of {alpha}-decay events on the stability of the U{sup 6+}-phases, we report, for the first time, the results of ion beam irradiations (1.0 MeV Kr{sup 2+}) of U{sup 6+}-phases. The heavy-particle irradiations are used to simulate the ballistic interactions of the recoil-nucleus of an {alpha}-decay event with the surrounding structure. The Kr{sup 2+}-irradiation decomposed the U{sup 6+}-phases to UO{sub 2} nanocrystals at doses as low as 0.006 displacements per atom (dpa). U{sup 6+}-phases accumulate substantial radiation doses ({approx}1.0 displacement per atom) within 100,000 years if the concentration of incorporated {sup 239}Pu is as high as 1 wt%. Similar nanocrystals of UO{sub 2} were observed in samples from the natural fission reactors at Oklo, Gabon. Multiple cycles of radiation-induced decomposition to UO{sub 2} followed by alteration to U{sup 6+}-phases provide a mechanism for the remobilization of incorporated radionuclides.

  2. additives doped-uo2 pellets: Topics by E-print Network

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

    additives doped-uo2 pellets 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 Journal of Nuclear...

  3. UO Retirement Recognition Reception Pap Reception Hall, J.S. Museum of Art

    E-Print Network [OSTI]

    Oregon, University of

    UO Retirement Recognition Reception Papé Reception Hall, J.S. Museum of Art Thursday, June 16, 2011 Information Services 29½ Years Richard Edwards Early Childhood CARES 11 Years Kayla Hinds Architecture will not be attending the retirement reception. They asked that we announce their retirement. Robert Barton Theatre Arts

  4. f Fk66iCOP-] NBSIR 86-3422 uoL_ i 1

    E-Print Network [OSTI]

    Oak Ridge National Laboratory

    f Fk66iCOP-] NBSIR 86-3422 uoL_ i 1 The Performance of A Conventional Residential Sized Heat Pump RESIDENTIAL SIZED HEAT PUMP OPERATING WITH A NONAZEOTROPIC BINARY REFRIGERANT MIXTURE William Mulroy David unmodified residential heat pump designed for R22 when charged with a nonazeotropic refrigerant mixture (NARM

  5. UNIVERSITY OF OREGON SOLAR MONITORING LABORATORY The University of Oregon (UO) Solar Moni-

    E-Print Network [OSTI]

    Oregon, University of

    i UNIVERSITY OF OREGON SOLAR MONITORING LABORATORY The University of Oregon (UO) Solar Moni- toring Laboratory has been measuring incident solar radiation since 1975. Current support for this work comes from the Regional Solar Radiation Monitoring Project (RSRMP), a utility consortium project including the Bon

  6. 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.

  7. Microscale Controls on the Fate of Contaminant Uranium in the Vadose Zone, Hanford Site, Washington

    SciTech Connect (OSTI)

    McKinley, James P.; Zachara, John M.; Liu, Chongxuan; Heald, Steve M.; Prenitzer, Brenda I.; Kempshall, Brian

    2006-04-15T23:59:59.000Z

    An alkaline brine containing uranyl (UO22+) leaked to the thick unsaturated zone at the Hanford Site. X-ray and electron microprobe imaging showed that the uranium was associated with a minority of clasts, specifically granitic clasts occupying less than four percent of the sediment volume. XANES analysis at micron resolution showed the uranium to be hexavalent. The uranium was precipitated in microfractures as radiating clusters of uranyl silicates, and sorbed uranium was not observed on other surfaces. Compositional determinations of the 1-3 µm precipitates were difficult, but indicated a sodium potassium uranyl silicate, likely sodium boltwoodite. Observations suggested that uranyl was removed from pore waters by diffusion and precipitation in microfractures, where dissolved silica within the granite-equilibrated solution would cause supersaturation with respect to sodium boltwoodite. This hypothesis was tested using a diffusion reaction model operating at microscale. Conditions favoring precipitation were simulated to be transient, and driven by the compositional contrast between pore and fracture space. Pore-space conditions, including alkaline pH, were eventually imposed on the microfracture environment. However, conditions favoring precipitation were prolonged within the microfracture by reaction at the silicate mineral surface to buffer pH in a solubility limiting acidic state, and to replenish dissolved silica. During this time, uranyl was additionally removed to the fracture space by diffusion from pore space. Uranyl is effectively immobilized within the microfracture environment within the presently unsaturated vadose zone.

  8. 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.

  9. Ultraslow Wave Nuclear Burning of Uranium-Plutonium Fissile Medium on Epithermal Neutrons

    E-Print Network [OSTI]

    V. D. Rusov; V. A. Tarasov; M. V. Eingorn; S. A. Chernezhenko; A. A. Kakaev; V. M. Vashchenko; M. E. Beglaryan

    2014-09-29T23:59:59.000Z

    For a fissile medium, originally consisting of uranium-238, the investigation of fulfillment of the wave burning criterion in a wide range of neutron energies is conducted for the first time, and a possibility of wave nuclear burning not only in the region of fast neutrons, but also for cold, epithermal and resonance ones is discovered for the first time. For the first time the results of the investigation of the Feoktistov criterion fulfillment for a fissile medium, originally consisting of uranium-238 dioxide with enrichments 4.38%, 2.00%, 1.00%, 0.71% and 0.50% with respect to uranium-235, in the region of neutron energies 0.015-10.0eV are presented. These results indicate a possibility of ultraslow wave neutron-nuclear burning mode realization in the uranium-plutonium media, originally (before the wave initiation by external neutron source) having enrichments with respect to uranium-235, corresponding to the subcritical state, in the regions of cold, thermal, epithermal and resonance neutrons. In order to validate the conclusions, based on the slow wave neutron-nuclear burning criterion fulfillment depending on the neutron energy, the numerical modeling of ultraslow wave neutron-nuclear burning of a natural uranium in the epithermal region of neutron energies (0.1-7.0eV) was conducted for the first time. The presented simulated results indicate the realization of the ultraslow wave neutron-nuclear burning of the natural uranium for the epithermal neutrons.

  10. 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.

  11. Method for oxygen reduction in a uranium-recovery process. [US DOE patent application

    DOE Patents [OSTI]

    Hurst, F.J.; Brown, G.M.; Posey, F.A.

    1981-11-04T23:59:59.000Z

    An improvement in effecting uranium recovery from phosphoric acid solutions is provided by sparging dissolved oxygen contained in solutions and solvents used in a reductive stripping stage with an effective volume of a nonoxidizing gas before the introduction of the solutions and solvents into the stage. Effective volumes of nonoxidizing gases, selected from the group consisting of argon, carbon dioxide, carbon monoxide, helium, hydrogen, nitrogen, sulfur dioxide, and mixtures thereof, displace oxygen from the solutions and solvents thereby reduce deleterious effects of oxygen such as excessive consumption of elemental or ferrous iron and accumulation of complex iron phosphates or cruds.

  12. 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.

  13. CARBON DIOXIDE AND OUR OCEAN LEGACY

    E-Print Network [OSTI]

    is a biologist at the California State Univer- sity San Marcos, with expertise in the effects of carbon dioxideCARBON DIOXIDE AND OUR OCEAN LEGACY G Carbon Dioxide: Our Role The United States is the single. Every day the average American adds about 118 pounds of carbon dioxide to the atmos- phere, due largely

  14. Carbon Dioxide Sequestration Industrial-scale processes are available for separating carbon dioxide from the post-

    E-Print Network [OSTI]

    Carbon Dioxide Sequestration Industrial-scale processes are available for separating carbon dioxide dioxide separation and sequestration because the lower cost of carbon dioxide separation from for injection of carbon dioxide into oil or gas-bearing formations. An advantage of sequestration involving

  15. 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.

  16. Criticality experiments with low enriched UO/sub 2/ fuel rods in water containing dissolved gadolinium

    SciTech Connect (OSTI)

    Bierman, S.R.; Murphy, E.S.; Clayton, E.D.; Keay, R.T.

    1984-02-01T23:59:59.000Z

    The results obtained in a criticality experiments program performed for British Nuclear Fuels, Ltd. (BNFL) under contract with the United States Department of Energy (USDOE) are presented in this report along with a complete description of the experiments. The experiments involved low enriched UO/sub 2/ and PuO/sub 2/-UO/sub 2/ fuel rods in water containing dissolved gadolinium, and are in direct support of BNFL plans to use soluble compounds of the neutron poison gadolinium as a primary criticality safeguard in the reprocessing of low enriched nuclear fuels. The experiments were designed primarily to provide data for validating a calculation method being developed for BNFL design and safety assessments, and to obtain data for the use of gadolinium as a neutron poison in nuclear chemical plant operations - particularly fuel dissolution. The experiments program covers a wide range of neutron moderation (near optimum to very under-moderated) and a wide range of gadolinium concentration (zero to about 2.5 g Gd/l). The measurements provide critical and subcritical k/sub eff/ data (1 greater than or equal to k/sub eff/ greater than or equal to 0.87) on fuel-water assemblies of UO/sub 2/ rods at two enrichments (2.35 wt % and 4.31 wt % /sup 235/U) and on mixed fuel-water assemblies of UO/sub 2/ and PuO/sub 2/-UO/sub 2/ rods containing 4.31 wt % /sup 235/U and 2 wt % PuO/sub 2/ in natural UO/sub 2/ respectively. Critical size of the lattices was determined with water containing no gadolinium and with water containing dissolved gadolinium nitrate. Pulsed neutron source measurements were performed to determine subcritical k/sub eff/ values as additional amounts of gadolinium were successively dissolved in the water of each critical assembly. Fission rate measurements in /sup 235/U using solid state track recorders were made in each of the three unpoisoned critical assemblies, and in the near-optimum moderated and the close-packed poisoned assemblies of this fuel.

  17. 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.

  18. 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

  19. Carbon Dioxide: Threat or Opportunity?

    E-Print Network [OSTI]

    McKinney, A. R.

    1982-01-01T23:59:59.000Z

    catastrophic long term effects on world climate. An alternative to discharging carbon dioxide into the atmosphere is to find new uses. One possible use is in 'Biofactories'. Biofactories may be achieved by exploiting two new developing technologies: Solar...

  20. Reducing carbon dioxide to products

    DOE Patents [OSTI]

    Cole, Emily Barton; Sivasankar, Narayanappa; Parajuli, Rishi; Keets, Kate A

    2014-09-30T23:59:59.000Z

    A method reducing carbon dioxide to one or more products may include steps (A) to (C). Step (A) may bubble said carbon dioxide into a solution of an electrolyte and a catalyst in a divided electrochemical cell. The divided electrochemical cell may include an anode in a first cell compartment and a cathode in a second cell compartment. The cathode may reduce said carbon dioxide into said products. Step (B) may adjust one or more of (a) a cathode material, (b) a surface morphology of said cathode, (c) said electrolyte, (d) a manner in which said carbon dioxide is bubbled, (e), a pH level of said solution, and (f) an electrical potential of said divided electrochemical cell, to vary at least one of (i) which of said products is produced and (ii) a faradaic yield of said products. Step (C) may separate said products from said solution.

  1. Recuperative supercritical carbon dioxide cycle

    DOE Patents [OSTI]

    Sonwane, Chandrashekhar; Sprouse, Kenneth M; Subbaraman, Ganesan; O'Connor, George M; Johnson, Gregory A

    2014-11-18T23:59:59.000Z

    A power plant includes a closed loop, supercritical carbon dioxide system (CLS-CO.sub.2 system). The CLS-CO.sub.2 system includes a turbine-generator and a high temperature recuperator (HTR) that is arranged to receive expanded carbon dioxide from the turbine-generator. The HTR includes a plurality of heat exchangers that define respective heat exchange areas. At least two of the heat exchangers have different heat exchange areas.

  2. Use of depleted uranium silicate glass to minimize release of radionuclides from spent nuclear fuel waste packages

    SciTech Connect (OSTI)

    Forsberg, C.W.

    1996-01-20T23:59:59.000Z

    A Depleted Uranium Silicate Container Backfill System (DUSCOBS) is proposed that would use small, isotopically-depleted uranium silicate glass beads as a backfill material inside repository waste packages containing spent nuclear fuel (SNF). The uranium silicate glass beads would fill the void space inside the package including the coolant channels inside SNF assemblies. Based on preliminary analysis, the following benefits have been identified. DUSCOBS improves repository waste package performance by three mechanisms. First, it reduces the radionuclide releases from SNF when water enters the waste package by creating a local uranium silicate saturated groundwater environment that suppresses (a) the dissolution and/or transformation of uranium dioxide fuel pellets and, hence, (b) the release of radionuclides incorporated into the SNF pellets. Second, the potential for long-term nuclear criticality is reduced by isotopic exchange of enriched uranium in SNF with the depleted uranium (DU) in the glass. Third, the backfill reduces radiation interactions between SNF and the local environment (package and local geology) and thus reduces generation of hydrogen, acids, and other chemicals that degrade the waste package system. Finally, DUSCOBS provides a potential method to dispose of significant quantities of excess DU from uranium enrichment plants at potential economic savings. DUSCOBS is a new concept. Consequently, the concept has not been optimized or demonstrated in laboratory experiments.

  3. 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.

  4. Synthesis and X-ray structural investigation of K{sub 8}[(UO{sub 2}){sub 2}(C{sub 2}O{sub 4}){sub 2}(SeO{sub 4}){sub 4}] . 2H{sub 2}O

    SciTech Connect (OSTI)

    Serezhkina, L. B., E-mail: lserezh@ssu.samara.ru [Samara State University (Russian Federation); Peresypkina, E. V.; Virovets, A. V. [Russian Academy of Sciences, Nikolaev Institute of Inorganic Chemistry, Siberian Branch (Russian Federation); Verevkin, A. G.; Pushkin, D. V. [Samara State University (Russian Federation)

    2009-01-15T23:59:59.000Z

    Single crystals of the compound K{sub 8}[(UO{sub 2}){sub 2}(C{sub 2}O{sub 4}){sub 2}(SeO{sub 4})4] . 2H{sub 2}O (I) are synthesized, and their structure is investigated using X-ray diffraction. Compound I crystallizes in the monoclinic system with the unit cell parameters a = 14.9290(4) A, b = 7.2800(2) A, c = 15.3165(4) A, {beta} = 109.188(1){sup o}, V = 1572.17(7) A{sup 3}, space group P2{sub 1}/n, Z = 2, and R = 0.0297. The uranium-containing structural units of crystals I are dimers of the composition [(UO {sub 2}){sub 2}(C{sub 2}O{sub 4}){sub 2}(SeO{sub 4}){sub 4}]{sup 8-}, which belong to the crystal-chemical group AB{sup 01}B{sup 2}M{sup 1} (A = UO{sub 2}{sup 2+}, B{sup 01} = C{sub 2}O{sub 4}{sup 2-}, B{sup 2} = SeO{sub 4}{sup 2-}, M{sup 1} = SeO{sub 4}{sup 2-}) of the uranyl complexes. The [(UO{sub 2}){sub 2}(C{sub 2}O{sub 4}){sub 2}(SeO{sub 4}){sub 4}]{sup 8-} dimers are joined into a three-dimensional framework through electrostatic interactions with the outer-sphere potassium cations.

  5. UO{sub 2} corrosion in high surface-area-to-volume batch experiments.

    SciTech Connect (OSTI)

    Bates, J. K.; Finch, R. J.; Hanchar, J. M.; Wolf, S. F.

    1997-12-08T23:59:59.000Z

    Unsaturated drip tests have been used to investigate the alteration of unirradiated UO{sub 2} and spent UO{sub 2} fuel in an unsaturated environment such as may be expected in the proposed repository at Yucca Mountain. In these tests, simulated groundwater is periodically injected onto a sample at 90 C in a steel vessel. The solids react with the dripping groundwater and water condensed on surfaces to form a suite of U(VI) alteration phases. Solution chemistry is determined from leachate at the bottom of each vessel after the leachate stops interacting with the solids. A more detailed knowledge of the compositional evolution of the leachate is desirable. By providing just enough water to maintain a thin film of water on a small quantity of fuel in batch experiments, we can more closely monitor the compositional changes to the water as it reacts to form alteration phases.

  6. UO2 CORROSION IN HIGH SURFACE-AREA-TO-VOLUME BATCH EXPERIMENTS

    SciTech Connect (OSTI)

    Finch, Robert J.; Wolf, Stephen F.; Hanchar, John M.; Bates, John K.

    1998-05-11T23:59:59.000Z

    Unsaturated drip tests have been used to investigate the alteration of unirradiated UO{sub 2} and spent UO{sub 2} fuel in an unsaturated environment, such as may be expected in the proposed repository at Yucca Mountain. In these tests, simulated groundwater is periodically injected onto a sample at 90 C in a steel vessel. The solids react with the dripping groundwater and water condensed on surfaces to form a suite of U(VI) alteration phases. Solution chemistry is determined from leachate at the bottom of each vessel after the leachate stops interacting with the solids. A more detailed knowledge of the compositional evolution of the leachate is desirable. By providing just enough water to maintain a thin film of water on a small quantity of fuel in batch experiments, we can more closely monitor the compositional changes to the water as it reacts to form alteration phases.

  7. Bubble formation and Kr distribution in Kr-irradiated UO2

    SciTech Connect (OSTI)

    L.F. He; B. Valderrama; A.-R. Hassan; J. Yu; M. Gupta; J. Pakarinen; H.B. Henderson; J. Gan; M.A. Kirk; A.T. Nelson; M.V. Manuel; A. El-Azab; T.R. Allen

    2015-01-01T23:59:59.000Z

    In situ and ex situ transmission electron microscopy observation of small Kr bubbles in both single-crystal and polycrystalline UO2 were conducted to understand the inert gas bubble behavior in oxide nuclear fuel. The bubble size and volume swelling are shown as a weak function of ion dose but strongly depend on the temperature. The Kr bubble formation at room temperature was observed for the first time. The depth profiles of implanted Kr determined by atom probe tomography are in good agreement with the calculated profiles by SRIM, but the measured concentration of Kr is about 1/3 of calculated one. This difference is mainly due to low solubility of Kr in UO2 matrix, which has been confirmed by both density-functional theory calculations and chemical equilibrium analysis.

  8. argon carbon dioxide: Topics by E-print Network

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

    carbon dioxide levels in the atmosphere. Additional measurements by scientists working 10 Carbon Dioxide Sequestration and Utilization CiteSeer Summary: ? Carbon dioxide (CO2) in...

  9. applied carbon dioxide: Topics by E-print Network

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

    carbon dioxide levels in the atmosphere. Additional measurements by scientists working 8 Carbon Dioxide Sequestration and Utilization CiteSeer Summary: ? Carbon dioxide (CO2) in...

  10. aqueous carbon dioxide: Topics by E-print Network

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

    carbon dioxide levels in the atmosphere. Additional measurements by scientists working 12 Carbon Dioxide Sequestration and Utilization CiteSeer Summary: ? Carbon dioxide (CO2) in...

  11. 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.

  12. 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...

  13. 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...

  14. Recovery of UO[sub 2]/PuO[sub 2] in IFR electrorefining process

    DOE Patents [OSTI]

    Tomczuk, Z.; Miller, W.E.

    1994-10-18T23:59:59.000Z

    A process is described for converting PuO[sub 2] and UO[sub 2] present in an electrorefiner to the chlorides, by contacting the PuO[sub 2] and UO[sub 2] with Li metal in the presence of an alkali metal chloride salt substantially free of rare earth and actinide chlorides for a time and at a temperature sufficient to convert the UO[sub 2] and PuO[sub 2] to metals while converting Li metal to Li[sub 2]O. Li[sub 2]O is removed either by reducing with rare earth metals or by providing an oxygen electrode for transporting O[sub 2] out of the electrorefiner and a cathode, and thereafter applying an emf to the electrorefiner electrodes sufficient to cause the Li[sub 2]O to disassociate to O[sub 2] and Li metal but insufficient to decompose the alkali metal chloride salt. The U and Pu and excess lithium are then converted to chlorides by reaction with CdCl[sub 2].

  15. Recovery of UO.sub.2 /Pu O.sub.2 in IFR electrorefining process

    DOE Patents [OSTI]

    Tomczuk, Zygmunt (Lockport, IL); Miller, William E. (Naperville, IL)

    1994-01-01T23:59:59.000Z

    A process for converting PuO.sub.2 and UO.sub.2 present in an electrorefiner to the chlorides, by contacting the PuO.sub.2 and UO.sub.2 with Li metal in the presence of an alkali metal chloride salt substantially free of rare earth and actinide chlorides for a time and at a temperature sufficient to convert the UO.sub.2 and PuO.sub.2 to metals while converting Li metal to Li.sub.2 O. Li.sub.2 O is removed either by reducing with rare earth metals or by providing an oxygen electrode for transporting O.sub.2 out of the electrorefiner and a cathode, and thereafter applying an emf to the electrorefiner electrodes sufficient to cause the Li.sub.2 O to disassociate to O.sub.2 and Li metal but insufficient to decompose the alkali metal chloride salt. The U and Pu and excess lithium are then converted to chlorides by reaction with CdCl.sub.2.

  16. 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...

  17. Lattice anisotropy, electronic and chemical structures of uranyl carbonate, UO2CO3, from

    E-Print Network [OSTI]

    Boyer, Edmond

    localization function mapping, oxygen atoms are found to preferentially bind with uranium for one sublattice Binary and ternary uranium natural and synthetic compounds are known and characterized (mainly X the electron band structure, the equation of state (EOS) as well as the properties of chemi- cal bonding

  18. 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.

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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.

  6. Minimum mass of moderator required for criticality of homogeneous low-enriched uranium systems

    SciTech Connect (OSTI)

    Jordan, W.C.; Turner, J.C.

    1992-12-01T23:59:59.000Z

    A parametric calculational analysis has been performed in order to estimate the minimum mass of moderator required for criticality of homogeneous low-enriched uranium systems. The analysis was performed using a version of the SCALE-4.0 code system and the 27-group ENDF/B-IV cross-section library. Water-moderated uranyl fluoride (UO[sub 2]F[sub 2] and H[sub 2]O) and hydrofluoric-acid-moderated uranium hexaflouride (UF[sub 6] and HF) systems were considered in the analysis over enrichments of 1.4 to 5 wt % [sup 235]U. Estimates of the minimum critical volume, minimum critical mass of uranium, and the minimum mass of moderator required for criticality are presented. There was significant disagreement between the values generated in this study when compared with a similar undocumented study performed in 1983 using ANISN and the Knight-modified Hansen-Roach cross sections. An investigation into the cause of the disagreement was made, and the results are presented.

  7. Minimum mass of moderator required for criticality of homogeneous low-enriched uranium systems

    SciTech Connect (OSTI)

    Jordan, W.C.; Turner, J.C.

    1992-12-01T23:59:59.000Z

    A parametric calculational analysis has been performed in order to estimate the minimum mass of moderator required for criticality of homogeneous low-enriched uranium systems. The analysis was performed using a version of the SCALE-4.0 code system and the 27-group ENDF/B-IV cross-section library. Water-moderated uranyl fluoride (UO{sub 2}F{sub 2} and H{sub 2}O) and hydrofluoric-acid-moderated uranium hexaflouride (UF{sub 6} and HF) systems were considered in the analysis over enrichments of 1.4 to 5 wt % {sup 235}U. Estimates of the minimum critical volume, minimum critical mass of uranium, and the minimum mass of moderator required for criticality are presented. There was significant disagreement between the values generated in this study when compared with a similar undocumented study performed in 1983 using ANISN and the Knight-modified Hansen-Roach cross sections. An investigation into the cause of the disagreement was made, and the results are presented.

  8. Prospects for the recovery of uranium from seawater

    SciTech Connect (OSTI)

    Best, F.R.; Driscoll, M.

    1986-04-01T23:59:59.000Z

    A computer program entitled URPE (Uranium Recovery Performance and Economics) has been developed to simulate the engineering performance and provide an economic analysis of a plant recovering uranium from seawater. The conceptual system design used as the focal point for the more general analysis consists of a floating oil-rig type of platform single-point moored in an open ocean current, using either high-volume-low-head axial pumps or the velocity head of the ambient ocean current to force seawater through a mass transfer medium (hydrous titanium oxide (HTO) coated onto particle beds or stacked tubes). Uranium is recovered from the seawater by an adsorption process, and later eluted from the adsober by an ammonium carbonate solution. A multiproduct cogenerating plant on board the platform burns coal to raise steam for electricity generation, desalination, and process heat requirements. Scrubbed stack gas from the plant is processed to recover carbon dioxide for chemical make-up needs. The equilibrium isotherm and the diffusion constant for the uranyl-HTO system, which are needed for bed performance calculations, have been calculated based on the data reported in the literature. In addition, a technique for calculating the rate constant of a fixed-bed adsoorbing system has been developed for use with Thomas' solution for predicting fixed-bed performance.

  9. Leaching patterns and secondary phase formation during unsaturated leaching of UO{sub 2} at 90{degrees}C

    SciTech Connect (OSTI)

    Wronkiewicz, D.J.; Bates, J.K.; Gerding, T.J.; Veleckis, E.; Tani, B.S.

    1991-11-01T23:59:59.000Z

    Experiments are being conducted that examine the reaction of UO{sub 2} with dripping oxygenated ground water at 90{degrees}C. The experiments are designed to identify secondary phases formed during UO{sub 2} alteration, evaluate parameters controlling U release, and act as scoping tests for studies with spent fuel. This study is the first of its kind that examines the alteration of UO{sub 2} under unsaturated conditions expected to exist at the proposed Yucca Mountain repository site. Results suggest the UO{sub 2} matrix will readily react within a few months after being exposed to simulated Yucca Mountain conditions. A pulse of rapid U release, combined with the formation of dehydrated schoepite on the UO{sub 2} surface, characterizes the reaction between one to two years. Rapid dissolution of intergrain boundaries and spallation of UO{sub 2} granules appears to be responsible for much of the U released. Differential release of the UO{sub 2} granules may be responsible for much of the variation observed between duplicate experiments. Less than 5 wt % of the released U remains in solution or in a suspended form, while the remaining settles out of solution as fine particles or is reprecipitated as secondary phases. Subsequent to the pulse period, U release rates decline and a more stable assemblage of uranyl silicate phases are formed by incorporating cations from the ground water leachant. Uranophane, boltwoodite, and sklodowskite appear as the final solubility limiting phases that form in these tests. This observed paragenetic sequence (from uraninite to schoepite-type phases to uranyl silicates) is identical to those observed in weathered zones of natural uraninite occurrences. The combined results indicate that the release of radionuclides from spent fuel may not be limited by U solubility constraints, but that spallation of particulate matter may be an important, if not the dominant release mechanism affecting release.

  10. 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

  11. Feasibility of Partial ZrO[subscript 2] Coatings on Outer Surface of Annular UO[subscript 2] Pellets to Control Gap Conductance

    E-Print Network [OSTI]

    Feinroth, H.

    The viability of depositing a thin porous coating of zirconia on the outer surface of an annular UO[subscript 2] pellet

  12. Gas-phase energies of actinide oxides -- an assessment of neutral and cationic monoxides and dioxides from thorium to curium

    SciTech Connect (OSTI)

    Marcalo, Joaquim; Gibson, John K.

    2009-08-10T23:59:59.000Z

    An assessment of the gas-phase energetics of neutral and singly and doubly charged cationic actinide monoxides and dioxides of thorium, protactinium, uranium, neptunium, plutonium, americium, and curium is presented. A consistent set of metal-oxygen bond dissociation enthalpies, ionization energies, and enthalpies of formation, including new or revised values, is proposed, mainly based on recent experimental data and on correlations with the electronic energetics of the atoms or cations and with condensed-phase thermochemistry.

  13. VAPOR + LIQUID EQUILIBRIUM OF WATER, CARBON DIOXIDE, AND THE BINARY SYSTEM WATER + CARBON DIOXIDE FROM

    E-Print Network [OSTI]

    ) and their binary mixtures (between 348 and 393 K). The properties of supercritical carbon dioxide were determinedVAPOR + LIQUID EQUILIBRIUM OF WATER, CARBON DIOXIDE, AND THE BINARY SYSTEM WATER + CARBON DIOXIDE the vapor-liquid equilibrium of water (between 323 and 573 K), carbon dioxide (between 230 and 290 K

  14. 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

  15. 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.

  16. 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

  17. Final Report - Gas Generation Testing of Uranium Metal in Simulated K Basin Sludge and in Grouted Sludge Waste Forms

    SciTech Connect (OSTI)

    Delegard, Calvin H.; Schmidt, Andrew J.; Sell, Rachel L.; Sinkov, Sergei I.; Bryan, Samuel A.; Gano, Sue; Thornton, Brenda M.

    2004-08-19T23:59:59.000Z

    The Waste Isolation Pilot Plant (WIPP) is being considered for the disposal of K Basin sludge as RH-TRU. Because the hydrogen gas concentration in the 55-gallon RH-TRU sealed drums to be transported to WIPP is limited by flammability safety, the number of containers and shipments likely will be driven by the rate of hydrogen generated by the uranium metal-water reaction (U + 2 H{sub 2}O {yields} UO{sub 2} + 2 H{sub 2}) in combination with the hydrogen generated from water and organic radiolysis. Gas generation testing was conducted with uranium metal particles of known surface area, in simulated K West (KW) Basin canister sludge and immobilized in candidate grout solidification matrices. This study evaluated potential for Portland cement and magnesium phosphate grouts to inhibit the reaction of water with uranium metal in the sludge and thereby permit higher sludge loading to the disposed waste form. The best of the grouted waste forms decreased the uranium metal-water reaction by a factor of four.

  18. Aspects of uranium chemistry pertaining to UF{sub 6} cylinder handling

    SciTech Connect (OSTI)

    Ritter, R.L.; Barber, E.J. [Martin Marietta Energy Systems, Inc., Oak Ridge, TN (United States)

    1991-12-31T23:59:59.000Z

    Under normal conditions, the bulk of UF{sub 6} in storage cylinders will be in the solid state with an overpressure of gaseous UF{sub 6} well below one atmosphere. Corrosion of the interior of the cylinder will be very slow, with formation of a small amount of reduced fluoride, probably U{sub 2}F{sub 9}. The UO{sub 3}-HF-H{sub 2}O phase diagram indicates that reaction of any inleaking water vapor with the solid UF{sub 6} will generate the solid material [H{sub 3}O]{sub 2}(U(OH){sub 4}F{sub 4}) in equilibrium with an aqueous HF solution containing only small amounts of uranium. The corrosion of the steel cylinder by these materials may be enhanced over that observed with gaseous anhydrous UF{sub 6}.

  19. 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.

  20. SEISMIC MONITORING OF CARBON DIOXIDE FLUID FLOW

    E-Print Network [OSTI]

    Santos, Juan

    SEISMIC MONITORING OF CARBON DIOXIDE FLUID FLOW J. E. Santos1, G. B. Savioli2, J. M. Carcione3, DĀ´e, Argentina SEISMIC MONITORING OF CARBON DIOXIDE FLUID FLOW Ā­ p. #12;Introduction. I Storage of CO2). SEISMIC MONITORING OF CARBON DIOXIDE FLUID FLOW Ā­ p. #12;Introduction. II CO2 is separated from natural

  1. Excited States and Luminescent Properties of UO2F2 and Its Solvated Complexes in Aqueous Solution

    SciTech Connect (OSTI)

    Su, Jing; Wang, Zheming; Pan, Duoqiang; Li, Jun

    2014-08-20T23:59:59.000Z

    The electronic absorption and emission spectra of free UO2F2 and its water solvated complexes below 32,000 cm?1 are investigated at the levels of ab initio CASPT2 and CCSD(T) with inclusion of scalar relativistic and spin-orbit coupling effects. The influence of the water coordination on the electronic spectra of UO2F2 is explored by investigating the excited states of solvated complexes (H2O)nUO2F2 (n = 1?3). In these uranyl-complexes, water coordination is found to have appreciable influence on the 3? (? = 1g) character of the luminescent state and on the electronic spectral shape. The simulated luminescence spectral curves based on the calculated spectral parameters of (H2O)nUO2F2 from CCSD(T) approach agree well with experimental spectra in aqueous solution at both near liquid helium temperature and room temperature. The possible luminescence spectra of free UO2F2 in gas phase are predicted based on CASPT2 and CCSD(T) results, respectively, by considering three symmetric vibration modes. The effect of competition between spin-orbital coupling and ligand field repulsion on the luminescent state properties is discussed.

  2. 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 Ā· Deborah LebowAal/EPA Region 8 Air Program Introduction to Titan Uranium USA;PROJECT OVERVIEW Ā·Site LocationĀ·Site Location Ā·Fremont , Wyoming Ā·Existing Uranium Mine Permit 381C

  3. 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

  4. Solar and Photovoltaic Data from the University of Oregon Solar Radiation Monitoring Laboratory (UO SRML)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    The UO SRML is a regional solar radiation data center whose goal is to provide sound solar resource data for planning, design, deployment, and operation of solar electric facilities in the Pacific Northwest. The laboratory has been in operation since 1975. Solar data includes solar resource maps, cumulative summary data, daily totals, monthly averages, single element profile data, parsed TMY2 data, and select multifilter radiometer data. A data plotting program and other software tools are also provided. Shade analysis information and contour plots showing the effect of tilt and orientation on annual solar electric system perfomance make up a large part of the photovoltaics data.(Specialized Interface)

  5. An Overview of Current and Past W-UO[2] CERMET Fuel Fabrication Technology

    SciTech Connect (OSTI)

    Douglas E. Burkes; Daniel M. Wachs; James E. Werner; Steven D. Howe

    2007-06-01T23:59:59.000Z

    Studies dating back to the late 1940s performed by a number of different organizations and laboratories have established the major advantages of Nuclear Thermal Propulsion (NTP) systems, particularly for manned missions. A number of NTP projects have been initiated since this time; none have had any sustained fuel development work that appreciably contributed to fuel fabrication or performance data from this era. As interest in these missions returns and previous space nuclear power researchers begin to retire, fuel fabrication technologies must be revisited, so that established technologies can be transferred to young researchers seamlessly and updated, more advanced processes can be employed to develop successful NTP fuels. CERMET fuels, specifically W-UO2, are of particular interest to the next generation NTP plans since these fuels have shown significant advantages over other fuel types, such as relatively high burnup, no significant failures under severe transient conditions, capability of accommodating a large fission product inventory during irradiation and compatibility with flowing hot hydrogen. Examples of previous fabrication routes involved with CERMET fuels include hot isostatic pressing (HIPing) and press and sinter, whereas newer technologies, such as spark plasma sintering, combustion synthesis and microsphere fabrication might be well suited to produce high quality, effective fuel elements. These advanced technologies may address common issues with CERMET fuels, such as grain growth, ductile to brittle transition temperature and UO2 stoichiometry, more effectively than the commonly accepted ‘traditional’ fabrication routes. Bonding of fuel elements, especially if the fabrication process demands production of smaller element segments, must be investigated. Advanced brazing techniques and compounds are now available that could produce a higher quality bond segment with increased ease in joining. This paper will briefly address the history of CERMET fuel fabrication technology as related to the GE 710 and ANL Nuclear Rocket Programs, in addition to discussing future plans, viable alternatives and preliminary investigations for W-UO2 CERMET fuel fabrication. The intention of the talk is to provide the brief history and tie in an overview of current programs and investigations as related to NTP based W-UO2 CERMET fuel fabrication, and hopefully peak interest in advanced fuel fabrication technologies.

  6. Nuclear data uncertainties by the PWR MOX/UO{sub 2} core rod ejection benchmark

    SciTech Connect (OSTI)

    Pasichnyk, I.; Klein, M.; Velkov, K.; Zwermann, W.; Pautz, A. [Boltzmannstr. 14, D-85748 Garching b. Muenchen (Germany)

    2012-07-01T23:59:59.000Z

    Rod ejection transient of the OECD/NEA and U.S. NRC PWR MOX/UO{sub 2} core benchmark is considered under the influence of nuclear data uncertainties. Using the GRS uncertainty and sensitivity software package XSUSA the propagation of the uncertainties in nuclear data up to the transient calculations are considered. A statistically representative set of transient calculations is analyzed and both integral as well as local output quantities are compared with the benchmark results of different participants. It is shown that the uncertainties in nuclear data play a crucial role in the interpretation of the results of the simulation. (authors)

  7. 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.

  8. 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

  9. 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...

  10. 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...

  11. 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 

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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

  18. Grain boundary corrosion and alteration phase formation during the oxidative dissolution of UO{sub 2} pellets

    SciTech Connect (OSTI)

    Wronkiewicz, D.J.; Buck, E.C.; Bates, J.K.

    1996-12-31T23:59:59.000Z

    Alteration behavior of UO{sub 2} pellets following reaction under unsaturated drip-test conditions at 90 C for up to 10 years was examined by solid phase and leachate analyses. Sample reactions were characterized by preferential dissolution of grain boundaries between the original press-sintered UO{sub 2} granules comprising the samples, development of a polygonal network of open channels along the intergrain boundaries, and spallation of surface granules that had undergone severe grain boundary corrosion. The development of a dense mat of alteration phases after 2 years of reaction trapped loose granules, resulting in reduced rates of particulate U release. The paragenetic sequence of alteration phases that formed on the present samples was similar to that observed in surficial weathering zones of natural uraninite (UO{sub 2}) deposits, with alkali and alkaline earth uranyl silicates representing the long-term solubility-limiting phases for U in both systems.

  19. Ultraslow Wave Nuclear Burning of Uranium-Plutonium Fissile Medium on Epithermal Neutrons

    E-Print Network [OSTI]

    Rusov, V D; Eingorn, M V; Chernezhenko, S A; Kakaev, A A

    2014-01-01T23:59:59.000Z

    For a fissile medium, originally consisting of uranium-238, the investigation of fulfillment of the wave burning criterion in a wide range of neutron energies is conducted for the first time, and a possibility of wave nuclear burning not only in the region of fast neutrons, but also for cold, epithermal and resonance ones is discovered for the first time. For the first time the results of the investigation of the Feoktistov criterion fulfillment for a fissile medium, originally consisting of uranium-238 dioxide with enrichments 4.38%, 2.00%, 1.00%, 0.71% and 0.50% with respect to uranium-235, in the region of neutron energies 0.015-10.0eV are presented. These results indicate a possibility of ultraslow wave neutron-nuclear burning mode realization in the uranium-plutonium media, originally (before the wave initiation by external neutron source) having enrichments with respect to uranium-235, corresponding to the subcritical state, in the regions of cold, thermal, epithermal and resonance neutrons. In order to...

  20. DECAY HEAT CONDITIONS OF CURRENT AND NEXT GENERATION REACTORS

    E-Print Network [OSTI]

    Choe, JongSoo 1985-

    2012-05-04T23:59:59.000Z

    expects to operate the VHTR by 2021 (NGNP, A Report to Congress, 2008). Advanced Burner 3 Reactors (ABR) are Sodium-Cooled Fast Reactors (SFR) which are fast neutron spectrum and closed fuel cycle system reactors. Its management of actinides... enriched uranium dioxide(UO2 ) less than 5 wt% and gadolinia-uranium dioxide(Gd,UO2). The cladding material is ZIRLO which is a zirconium based alloy for improved corrosion resistance (US-APWR, 2011). The operation power of the ABWR is 3926 MWth. Its...

  1. Evaluation of Heterogeneous Options: Effects of MgO versus UO2 Matrix Selection for Minor Actinide Targets in a Sodium Fast Reactor

    SciTech Connect (OSTI)

    M. Pope; S. Bays; R. Ferrer

    2008-03-01T23:59:59.000Z

    The primary focus of this work was to compare MgO with UO2 as target matrix material options for burning minor actinides in a transmutation target within a sodium fast reactor. This analysis compared the transmutation performance of target assemblies having UO2 matrix to those having specifically MgO inert matrix.

  2. Destruction of plutonium using non-uranium fuels in pressurized water reactor peripheral assemblies

    SciTech Connect (OSTI)

    Chodak, P. III

    1996-05-01T23:59:59.000Z

    This thesis examines and confirms the feasibility of using non-uranium fuel in a pressurized water reactor (PWR) radial blanket to eliminate plutonium of both weapons and civilian origin. In the equilibrium cycle, the periphery of the PWR is loaded with alternating fresh and once burned non-uranium fuel assemblies, with the interior of the core comprised of conventional three batch UO{sub 2} assemblies. Plutonium throughput is such that there is no net plutonium production: production in the interior is offset by destruction in the periphery. Using this approach a 50 MT WGPu inventory could be eliminated in approximately 400 reactor years of operation. Assuming all other existing constraints were removed, the 72 operating US PWRs could disposition 50 MT of WGPu in 5.6 years. Use of a low fissile loading plutonium-erbium inert-oxide-matrix composition in the peripheral assemblies essentially destroys 100% of the {sup 239}Pu and {ge}90% {sub total}Pu over two 18 month fuel cycles. Core radial power peaking, reactivity vs EFPD profiles and core average reactivity coefficients were found to be comparable to standard PWR values. Hence, minimal impact on reload licensing is anticipated. Examination of potential candidate fuel matrices based on the existing experience base and thermo-physical properties resulted in the recommendation of three inert fuel matrix compositions for further study: zirconia, alumina and TRISO particle fuels. Objective metrics for quantifying the inherent proliferation resistance of plutonium host waste and fuel forms are proposed and were applied to compare the proposed spent WGPu non-uranium fuel to spent WGPu MOX fuels and WGPu borosilicate glass logs. The elimination disposition option spent non-uranium fuel product was found to present significantly greater barriers to proliferation than other plutonium disposal products.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Atomistic Simulations of Uranium Incorporation into Iron (Hydr...

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

    characterize the coordination environments of U incorporated in three Fe-(hydr)oxide minerals: goethite, magnetite, and hematite. The simulations provided information on U-O and...

  10. 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...

  11. 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...

  12. Forest transitions and ecosystem services in Zimbabwe Supervisors: Dr Casey Ryan (UoE), Dr Isla Grundy (University of Zimbabwe)

    E-Print Network [OSTI]

    Forest transitions and ecosystem services in Zimbabwe Supervisors: Dr Casey Ryan (UoE), Dr Isla and a variety of other ecosystem services. However the expansion of agricultural land and the curing of tobacco is accelerating deforestation and forest degradation rates. These structural changes to the ecosystem threaten

  13. A Study of UO2 Grain Boundary Structure and Thermal Resistance Change under Irradiation using Molecular Dynamics Simulations 

    E-Print Network [OSTI]

    Chen, Tianyi

    2013-08-02T23:59:59.000Z

    showing formation of intermetallic phases ........................................................................................................... 12 Figure 2.1 The thermal conductivity of UO2 as a function on temperature .................... 15... in the fissile materials creates localized heating in the fuel element, which is transferred to a coolant, and then be used to produce mechanical energy and ultimately electricity. Understanding the properties and behaviors of these fissile material compounds...

  14. NEAMS FPL M2 Milestone Report: Development of a UO? Grain Size Model using Multicale Modeling and Simulation

    SciTech Connect (OSTI)

    Michael R Tonks; Yongfeng Zhang; Xianming Bai

    2014-06-01T23:59:59.000Z

    This report summarizes development work funded by the Nuclear Energy Advanced Modeling Simulation program's Fuels Product Line (FPL) to develop a mechanistic model for the average grain size in UO? fuel. The model is developed using a multiscale modeling and simulation approach involving atomistic simulations, as well as mesoscale simulations using INL's MARMOT code.

  15. 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

  16. 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}.

  17. 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.

  18. SEISMIC MONITORING OF CARBON DIOXIDE FLUID FLOW

    E-Print Network [OSTI]

    santos

    SEISMIC MONITORING OF. CARBON DIOXIDE FLUID FLOW. J. E. Santos. 1. , G. B. Savioli. 2. , J. M. Carcione. 3. , D. Gei. 3. 1. CONICET, IGPUBA, Fac.

  19. Putting the pressure on carbon dioxide | EMSL

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

    on carbon dioxide Released: March 26, 2014 Improving the chances for fuel recovery and carbon sequestration Artwork from this research graces the cover of Environmental Science...

  20. SIMULATION OF CARBON DIOXIDE STORAGE APPLYING ...

    E-Print Network [OSTI]

    Capture and storage of Carbon dioxide in aquifers and reservoirs is one of the solutions to mitigate the greenhouse effect. Geophysical methods can be used to

  1. 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.

  2. 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.

  3. 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.

  4. 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...

  5. D9 experiment: heat removal from stratified UO/sub 2/ debris

    SciTech Connect (OSTI)

    Ottinger, C A; Mitchell, G W; Lipinski, R J; Kelly, J E

    1985-04-01T23:59:59.000Z

    The D9 experiment investigated the coolability of a shallow (77 mm), stratified urania bed in sodium. The bed was fission heated in the Annular Core Research Reactor (ACRR) at Sandia National Laboratories to simulate the effects of radioactive decay heating. It was the first stratified debris bed experiment to use an extended UO/sub 2/ particle size distribution (0.038 to 4.0 mm). Dryout occurred at powers ranging from 0.10 to 0.58 W/g, which was close to the incipient boiling power and before channels penetrated the subcooled zone in the bed, even with subcoolings as low as 80/sup 0/C. Channel penetration was observed after dryout began, but the bed became only moderately more coolable. All these observations agree with current models.

  6. Preparation of thorium-uranium gel spheres

    SciTech Connect (OSTI)

    Spence, R.D.; Haas, P.A.

    1980-01-01T23:59:59.000Z

    Ceramic oxide spheres with diameters of 15 to 1500 ..mu..m are being evaluated for fabrication of power reactor fuel rods. (Th,U)O/sub 2/ spheres can be prepared by internal or external chemical gelation of nitrate solutions or oxide sols. Two established external gelation techniques were tested but proved to be unsatisfactory for the intended application. Established internal gelation techniques for UO/sub 2/ spheres were applied with minor modifications to make 75% ThO/sub 2/-25% UO/sub 2/ spheres that sinter to diameters of 200 to 1400 ..mu..m (99% T.D.).

  7. 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. Lųvborg AUTOMATED URANIUM ANALYSIS BY DELAYED-NEUTRON COUNTING H. Kunzendorf, L. Lųvborg and E.M. Christiansen

  8. 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

  9. 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.

  10. 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.

  11. 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

  12. 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) Ā· 40 CFR 61

  13. URANIUM MILL TAILINGS RADON FLUX CALCULATIONS

    E-Print Network [OSTI]

    URANIUM MILL TAILINGS RADON FLUX CALCULATIONS PIĆ?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

  14. absorbing sulfur dioxide: Topics by E-print Network

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

    simulation to optimize carbon dioxide (CO2) sequestration and enhance oil recovery (CO2-EOR) based on known 158 Interglacials, Milankovitch Cycles, and Carbon Dioxide CERN...

  15. amorphous titanium dioxide: Topics by E-print Network

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

    simulation to optimize carbon dioxide (CO2) sequestration and enhance oil recovery (CO2-EOR) based on known 177 Interglacials, Milankovitch Cycles, and Carbon Dioxide CERN...

  16. acute sulphur dioxide: Topics by E-print Network

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

    simulation to optimize carbon dioxide (CO2) sequestration and enhance oil recovery (CO2-EOR) based on known 82 Interglacials, Milankovitch Cycles, and Carbon Dioxide CERN...

  17. addressing chlorine dioxide: Topics by E-print Network

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

    simulation to optimize carbon dioxide (CO2) sequestration and enhance oil recovery (CO2-EOR) based on known 103 Interglacials, Milankovitch Cycles, and Carbon Dioxide CERN...

  18. Water and Carbon Dioxide Adsorption at Olivine Surfaces. | EMSL

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

    and Carbon Dioxide Adsorption at Olivine Surfaces. Water and Carbon Dioxide Adsorption at Olivine Surfaces. Abstract: Plane-wave density functional theory (DFT) calculations were...

  19. Supercritical Carbon Dioxide Turbo-Expander and Heat Exchangers...

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

    Supercritical Carbon Dioxide Turbo-Expander and Heat Exchangers Supercritical Carbon Dioxide Turbo-Expander and Heat Exchangers This fact sheet describes a supercritical carbon...

  20. Haverford Researchers Create Carbon Dioxide-Separating Polymer

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

    Haverford College Researchers Create Carbon Dioxide-Separating Polymer Haverford College Researchers Create Carbon Dioxide-Separating Polymer August 1, 2012 | Tags: Basic Energy...

  1. Project Profile: Supercritical Carbon Dioxide Turbo-Expander...

    Energy Savers [EERE]

    Supercritical Carbon Dioxide Turbo-Expander and Heat Exchangers Project Profile: Supercritical Carbon Dioxide Turbo-Expander and Heat Exchangers SWRI Logo The Southwest Research...

  2. Carbon dioxide-assisted fabrication of highly uniform submicron...

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

    dioxide-assisted fabrication of highly uniform submicron-sized colloidal carbon spheres via hydrothermal carbonization Carbon dioxide-assisted fabrication of highly uniform...

  3. atmospheric sulphur dioxide: Topics by E-print Network

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

    carbon dioxide CERN Preprints Summary: The primary ingredient of Anthropogenic Global Warming hypothesis is the assumption that atmospheric carbon dioxide variations are the cause...

  4. atmospheric sulfur dioxide: Topics by E-print Network

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

    carbon dioxide CERN Preprints Summary: The primary ingredient of Anthropogenic Global Warming hypothesis is the assumption that atmospheric carbon dioxide variations are the cause...

  5. 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.

  6. Recovery of uranium from seawater; 15: Development of amidoxime resins with high sedimentation velocity for passively driver fluidized bed adsorbers

    SciTech Connect (OSTI)

    Egawa, Hiroaki; Kabay, N.; Jyo, A.; Hirono, Masaki; Shuto, Taketomi (Kumamoto Univ. (Japan). Dept. of Applied Chemistry)

    1994-03-01T23:59:59.000Z

    In order to design the amidoxime resins (RNH) suitable for circulating fluidized bed adsorbers, RNH were prepared from precursory acrylonitrile-divinylbenzene copolymer beads of different particle sizes, and chemical and physical properties of the resulting RNH were evaluated. Specific surface areas, pore structures, swelling ratios, and anion and cation-exchange capacities of RNH are little affected by the particle size, while their sedimentation velocities in water increase with an increase in particle size as expected from fluid dynamics. Although the uptake of uncomplexed uranyl ion from a uranyl nitrate solution (0.01 M) was not influenced by the particle size, the uranium uptake from seawater decreases with an increase in the particle size, indicating that the particle diffusion of the bulky complexed species UO[sub 2](CO[sub 3])[sub 3][sup 4[minus

  7. Carbon Dioxide for pH Control

    SciTech Connect (OSTI)

    Wagonner, R.C.

    2001-08-16T23:59:59.000Z

    Cardox, the major supplier of carbon dioxide, has developed a diffuser to introduce carbon dioxide into a water volume as small bubbles to minimize reagent loss to the atmosphere. This unit is integral to several configurations suggested for treatment to control alkalinity in water streams.

  8. Optimize carbon dioxide sequestration, enhance oil recovery

    E-Print Network [OSTI]

    - 1 - Optimize carbon dioxide sequestration, enhance oil recovery January 8, 2014 Los Alamos simulation to optimize carbon dioxide (CO2) sequestration and enhance oil recovery (CO2-EOR) based on known production. Due to carbon capture and storage technology advances, prolonged high oil prices

  9. Carbon dioxide storage professor Martin Blunt

    E-Print Network [OSTI]

    Carbon dioxide storage professor Martin Blunt executive summary Carbon Capture and Storage (CCS) referS to the Set of technologies developed to capture carbon dioxide (Co2) gas from the exhausts raises new issues of liability and risk. the focus of this briefing paper is on the storage of carbon

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Development of DU-AGG (Depleted Uranium Aggregate)

    SciTech Connect (OSTI)

    Lessing, P.A.

    1995-09-01T23:59:59.000Z

    Depleted uranium oxide (UO{sub 2} or U0{sub 3}) powder was mixed with fine mineral additives, pressed, and heated to about 1,250{degree}C. The additives were chemically constituted to result in an iron-enriched basalt (IEB). Melting and wetting of the IEB phase caused the urania powder compact to densify (sinter) via a liquid phase sintering mechanism. An inorganic lubricant was found to aid in green-forming of the body. Sintering was successful in oxidizing (air), inert (argon), or reducing (dry hydrogen containing) atmospheres. The use of ground U0{sub 3} powders (93 vol %) followed by sintering in a dry hydrogen-containing atmosphere significantly increased the density of samples (bulk density of 8.40 g/cm{sup 3} and apparent density of 9.48 g/cm{sup 3}, open porosity of 11.43%). An improvement in the microstructure (reduction in open porosity) was achieved when the vol % of U0{sub 3} was decreased to 80%. The bulk density increased to 8.59 g/cm{sup 3}, the apparent density decreased slightly to 8.82 g/cm{sup 3} (due to increase of low density IEB content), while the open porosity decreased to an excellent number of 2.78%. A representative sample derived from 80 vol % U0{sub 3} showed that most pores were closed pores and that, overall, the sample achieved the excellent relative density value of 94.1% of the estimated theoretical density (composite of U0{sub 2} and IEB). It is expected that ground powders of U0{sub 3} could be successfully used to mass produce lowcost aggregate using the green-forming technique of briquetting.

  15. Reactions of aluminum with uranium fluorides and oxyfluorides

    SciTech Connect (OSTI)

    Leitnaker, J.M.; Nichols, R.W.; Lankford, B.S. [Martin Marietta Energy Systems, Inc., Oak Ridge, TN (United States)

    1991-12-31T23:59:59.000Z

    Every 30 to 40 million operating hours a destructive reaction is observed in one of the {approximately}4000 large compressors that move UF{sub 6} through the gaseous diffusion plants. Despite its infrequency, such a reaction can be costly in terms of equipment and time. Laboratory experiments reveal that the presence of moderate pressures of UF{sub 6} actually cools heated aluminum, although thermodynamic calculations indicate the potential for a 3000-4000{degrees}C temperature rise. Within a narrow and rather low (<100 torr; 1 torr = 133.322 Pa) pressure range, however, the aluminum is seen to react with sufficient heat release to soften an alumina boat. Three things must occur in order for aluminum to react vigorously with either UF{sub 6} or UO{sub 2}F{sub 2}. 1. An initiating source of heat must be provided. In the compressors, this source can be friction, permitted by disruption of the balance of the large rotating part or by creep of the aluminum during a high-temperature treatment. In the absence of this heat source, compressors have operated for 40 years in UF{sub 6} without significant reaction. 2. The film protecting the aluminum must be breached. Melting (of UF{sub 5} at 620 K or aluminum at 930 K) can cause such a breach in laboratory experiments. In contrast, holding Al samples in UF{sub 6} at 870 K for several hours produces only moderate reaction. Rubbing in the cascade can undoubtedly breach the protective film. 3. Reaction products must not build up and smother the reaction. While uranium products tend to dissolve or dissipate in molten aluminum, AIF{sub 3} shows a remarkable tendency to surround and hence protect even molten aluminum. Hence the initial temperature rise must be rapid and sufficient to move reactants into a temperature region in which products are removed from the reaction site.

  16. Neutronics studies of uranium-based fully ceramic micro-encapsulated fuel for PWRs

    SciTech Connect (OSTI)

    George, N. M.; Maldonado, I. [Dept. of Nuclear Engineering, Univ. of Tennessee Knoxville, Knoxville, TN 37996-2300 (United States); Terrani, K.; Godfrey, A.; Gehin, J. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2012-07-01T23:59:59.000Z

    This study evaluates the core neutronics and fuel cycle characteristics using uranium-based fully ceramic micro-encapsulated (FCM) fuel in a pressurized water reactor (PWR). Specific PWR assembly designs with FCM fuel have been developed, which by virtue of their TRISO particle-based elements are expected to achieve higher fuel burnups while also increasing the tolerance to fuel failures. The SCALE 6.1 code package, developed and maintained at ORNL, was the primary software used to model the assembly designs. Analysis was performed using the SCALE double-heterogeneous (DH) fuel modeling capabilities; however, the Reactivity-Equivalent Physical Transformation (RPT) method was used for lattice calculations due to the long run times associated with the SCALE DH capability. In order to understand the impact on reactivity and reactor operating cycle length, a parametric study was performed by varying TRISO particle design features, such as kernel diameter, coating layer thicknesses, and packing fraction. Also, other features such as the selection of matrix material (SiC, zirconium) and fuel rod dimensions were studied. After evaluating different uranium-based fuels, the higher compound density of uranium mononitride (UN) proved to be favorable, as the parametric studies showed that the FCM particle fuel design will need roughly 12% additional fissile material in comparison to that of a standard UO{sub 2} rod in order to match the lifetime of an 18-month PWR cycle. Neutronically, the FCM fuel designs evaluated maintain acceptable design features in the areas of fuel lifetime and temperature coefficients of reactivity, as well as pin cell and assembly peaking factors. (authors)

  17. 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.

  18. 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...

  19. 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...

  20. Polyacrylamide-hydroxyapatite composite: Preparation, characterization and adsorptive features for uranium and thorium

    SciTech Connect (OSTI)

    Baybas, Demet, E-mail: dbaybas@cumhuriyet.edu.tr [Cumhuriyet University, Faculty of Science, Department of Chemistry, Kayseri, Sivas 58140 (Turkey)] [Cumhuriyet University, Faculty of Science, Department of Chemistry, Kayseri, Sivas 58140 (Turkey); Ulusoy, Ulvi, E-mail: ulusoy@cumhuriyet.edu.tr [Cumhuriyet University, Faculty of Science, Department of Chemistry, Kayseri, Sivas 58140 (Turkey)] [Cumhuriyet University, Faculty of Science, Department of Chemistry, Kayseri, Sivas 58140 (Turkey)

    2012-10-15T23:59:59.000Z

    The composite of synthetically produced hydroxyapatite (HAP) and polyacrylamide was prepared (PAAm-HAP) and characterized by BET, FT-IR, TGA, XRD, SEM and PZC analysis. The adsorptive features of HAP and PAAm-HAP were compared for UO{sub 2}{sup 2+} and Th{sup 4+}. The entrapment of HAP into PAAm-HAP did not change the structure of HAP. Both structures had high affinity to the studied ions. The adsorption capacity of PAAm-HAP was than that of HAP. The adsorption dependence on pH and ionic intensity provided supportive evidences for the effect of complex formation on adsorption process. The adsorption kinetics was well compatible to pseudo second order model. The values of enthalpy and entropy changes were positive. Th{sup 4+} adsorption from the leachate obtained from a regional fluorite rock confirmed the selectivity of PAAm-HAP for this ion. In consequence, PAAm-HAP should be considered amongst favorite adsorbents for especially deposition of nuclear waste containing U and Th, and radionuclide at secular equilibrium with these elements. - Graphical abstract: SEM images of hydroxyapatite (HAP) and polyacrylamide-hydroxyapatite (PAAm-HAP), and the adsorption isotherms for Uranium and Thorium. Highlights: Black-Right-Pointing-Pointer Composite of PAAm-HAP was synthesized from hydroxyapatite and polyacrylamide. Black-Right-Pointing-Pointer The materials were characterized by BET, FT-IR, XRD, SEM, TGA and PZC analysis. Black-Right-Pointing-Pointer HAP and PAAm-HAP had high sorption capacity and very rapid uptake for UO{sub 2}{sup 2+} and Th{sup 4+}. Black-Right-Pointing-Pointer Super porous PAAm was obtained from PAAm-HAP after its removal of HAP content. Black-Right-Pointing-Pointer The composite is potential for deposition of U, Th and its associate radionuclides.

  1. A brief history of the PUREX and UO{sub 3} facilities

    SciTech Connect (OSTI)

    Gerber, M.S.

    1993-11-01T23:59:59.000Z

    The Plutonium-Uranium Extraction (PUREX) Plant, conceived during the early Cold War years, was a vehicle to increase significantly US nuclear weapons production capacity. The original PUREX Plant was a concrete rectangle 1,005 feet long and 61.5 feet wide. The shielding capacity of the concrete was designed so that personnel in non-regulated service areas would not receive radiation in excess of 0.1 millirem per hour. This report discusses the design of the PUREX Plant, the production chronology, projects and equipment changes, equipment decontamination and reuse, waste management, and contamination events that have occurred during the operation of the plant. Additionally, the development and history of the Uranium Trioxide Plant are also covered.

  2. RADIATION-INDUCED DECOMPOSITION OF U(VI) ALTERATION PHASES OF UO2

    SciTech Connect (OSTI)

    S. Utsunomiya; R.C. Ewing

    2005-09-08T23:59:59.000Z

    U{sup 6+}-phases are common alteration products of spent nuclear fuel under oxidizing conditions, and they may potentially incorporate actinides, such as long-lived {sup 239}Pu and {sup 237}Np, delaying their transport to the biosphere. In order to evaluate the ballistic effects of {alpha}-decay events on the stability of the U{sup 6+}-phases, we report, for the first time, the results of ion beam irradiations (1.0 MeV Kr{sup 2+}) for six different structures of U{sup 6+}-phases: uranophane, kasolite, boltwoodite, saleeite, carnotite, and liebigite. The target uranyl-minerals were characterized by powder X-ray diffraction and identification confirmed by SAED (selected area electron diffraction) in TEM (transmission electron microscopy). The TEM observation revealed no initial contamination of uraninite in these U{sup 6+} phases. All of the samples were irradiated with in situ TEM observation using 1.0 MeV Kr{sup 2+} in the IVEM (intermediate-voltage electron microscope) at the IVEM-Tandem Facility of Argonne National Laboratory. The ion flux was 6.3 x 10{sup 11} ions/cm{sup 2}/sec. The specimen temperatures during irradiation were 298 and 673 K, respectively. The Kr{sup 2+}-irradiation decomposed the U{sup 6+}-phases to nanocrystals of UO{sub 2} at doses as low as 0.006 dpa. The cumulative doses for the pure U{sup 6+}-phases, e.g., uranophane, at 0.1 and 1 million years (m.y.) are calculated to be 0.009 and 0.09 dpa using SRIM2003. However, with the incorporation of 1 wt.% {sup 239}Pu, the calculated doses reach 0.27 and {approx}1.00 dpa in ten thousand and one hundred thousand years, respectively. Under oxidizing conditions, multiple cycles of radiation-induced decomposition to UO{sub 2} followed by alteration to U{sup 6+}-phases should be further investigated to determine the fate of trace elements that may have been incorporated in the U{sup 6+}-phases.

  3. SEQUESTERING CARBON DIOXIDE IN COALBEDS

    SciTech Connect (OSTI)

    K.A.M. Gasem; R.L. Robinson, Jr.; L.R. Radovic

    2001-06-15T23:59:59.000Z

    The authors' long term goal is to develop accurate prediction methods for describing the adsorption behavior of gas mixtures on solid adsorbents over complete ranges of temperature, pressure and adsorbent types. The major objectives of the project are to: (1) measure the adsorption behavior of pure CO{sub 2}, methane, nitrogen and their binary and ternary mixtures on several selected coals having different properties at temperatures and pressures applicable to the particular coal being studied, (2) generalize the adsorption results in terms of appropriate properties of the coals, to facilitate estimation of adsorption behavior for coals other than those studied experimentally, (3) delineate the sensitivity of the competitive adsorption of CO{sub 2}, methane and nitrogen to the specific characteristics of the coal on which they are adsorbed; establish the major differences (if any) in the nature of this competitive adsorption on different coals, and (4) test and/or develop theoretically-based mathematical models to represent accurately the adsorption behavior of mixtures of the type for which measurements are made. The specific accomplishments of this project during this reporting period are summarized below in three broad categories outlining experimentation, model development, and coal characterization. (1) Experimental Work: Our adsorption apparatus was reassembled, and all instruments were tested and calibrated. Having confirmed the viability of the experimental apparatus and procedures used, adsorption isotherms for pure methane, carbon dioxide and nitrogen on wet Fruitland coal were measured at 319.3 K (115 F) and pressures to 12.4 MPa (1800 psia). These measurements showed good agreement with our previous data and yielded an expected uncertainty of about 2%. Preparations are underway to measure adsorption isotherms for pure methane, carbon dioxide and nitrogen on two other coals. (2) Model Development: The experimental data were used to evaluate the predictive capabilities of various adsorption models, including the Langmuir/loading ratio correlation, two-dimensional cubic equations of state, and the local density model. In general, all models performed well for Type I adsorption exhibited by methane, nitrogen, and carbon dioxide up to 8.3 MPa (average deviations within 2%). However, for pressures higher than 8.3 MPa (1200 psia), carbon dioxide produced multilayer adsorption behavior similar to Type IV adsorption. Our results to date indicate that the SLD model may be a suitable choice for modeling multilayer coalbed gas adsorption. However, model improvements are required to (a) account for coal heterogeneity and structure complexity, and (b) provide for more accurate density predictions. (3) Coal Characterization: We have identified several well-characterized coals for use in our adsorption studies. The criteria for coal selection has been guided by the need for coals that (a) span the spectrum of properties encountered in coalbed methane production (such as variation in rank), and (b) originate from coalbed methane recovery sites (e.g., San Juan Basin, Black Warrior Basin, etc.). At Pennsylvania State University, we have completed calibrating our instruments using a well-characterized activated carbon. In addition, we have conducted CO{sub 2} and methane uptakes on four samples, including (a) a widely used commercial activated carbon, BPL from Calgon Carbon Corp.; (b) an Illinois No.6 bituminous coal from the Argonne Premium Coal sample bank; (c) a Fruitland Intermediate coal sample; (d) a dry Fruitland sample. The results are as expected, except for a greater sensitivity to the outgassing temperature. ''Standard'' outgassing conditions (e.g., 383.2 K, overnight), which are often used, may not be appropriate for gas storage in coalbeds. Conditions that are more representative of in-situ coal (approximately 313.2 K) may be much more appropriate. In addition, our results highlight the importance of assessing the degree of approach to adsorption equilibrium.

  4. Effective flow surface of porous materials with two populations of voids under internal pressure: I. a GTN model

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ). Such a microstructure is typical of the highly irradiated uranium dioxide (UO2), a nuclear fuel commonly used in nuclear several studies on the mechanical behavior of highly irradiated nuclear fuels at different scales (Vincent to the effective plastic flow surface of a bi-porous material saturated by a fluid. The material under

  5. Proceedings of IMECE04 2004 ASME International Mechanical Engineering Congress

    E-Print Network [OSTI]

    Motta, Arthur T.

    of uranium dioxide (UO2) encased in long thin tubes (called fuel cladding) made of zirconium alloys as coolant to remove the heat from the core and produce power. The fuel cladding has the functions procedures of Zr alloys so that corrosion of the zirconium alloy cladding tubing in nuclear reactors

  6. Methane-assisted combustion synthesis of nanocomposite tin dioxide materials

    E-Print Network [OSTI]

    Wooldridge, Margaret S.

    Methane-assisted combustion synthesis of nanocomposite tin dioxide materials S.D. Bakrania *, C., Ann Arbor, MI 48109-2125, USA Abstract Combustion synthesis of tin dioxide (SnO2) was studied using: Combustion synthesis; Nanoparticles; Tin dioxide; Metals 1. Introduction Tin dioxide (SnO2) is the most

  7. Displacement of crude oil by carbon dioxide

    E-Print Network [OSTI]

    Omole, Olusegun

    1980-01-01T23:59:59.000Z

    by Carbon Dioxide (December 1980) Olusegun Omole, B. S. , University of Ibadan, Nigeria Chairman of Advisory Committee: Dr. J. S. Osoba It has long been recognized that carbon dioxide could be used as an oil recovery agent. Both laboratory and field...- tion. Crude oil from the Foster Field in West Texas, of 7 cp and 34 API, 0 was used as the oil in place. Oil displacements were conducted at pres- sures between 750 psig and 1800 ps1g, and at a temperature of 110 F. 0 Carbon dioxide was injected...

  8. 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.

  9. The New Generation of Uranium In Situ Recovery Facilities: Design Improvements Should Reduce Radiological Impacts Relative to First Generation Uranium Solution Mining Plants

    SciTech Connect (OSTI)

    Brown, S.H. [CHP, SHB INC., Centennial, Colorado (United States)

    2008-07-01T23:59:59.000Z

    In the last few years, there has been a significant increase in the demand for Uranium as historical inventories have been consumed and new reactor orders are being placed. Numerous mineralized properties around the world are being evaluated for Uranium recovery and new mining / milling projects are being evaluated and developed. Ore bodies which are considered uneconomical to mine by conventional methods such as tunneling or open pits, can be candidates for non-conventional recovery techniques, involving considerably less capital expenditure. Technologies such as Uranium In Situ Leaching / In Situ Recovery (ISL / ISR - also referred to as 'solution mining'), have enabled commercial scale mining and milling of relatively small ore pockets of lower grade, and are expected to make a significant contribution to overall world wide uranium supplies over the next ten years. Commercial size solution mining production facilities have operated in the US since the mid 1970's. However, current designs are expected to result in less radiological wastes and emissions relative to these 'first' generation plants (which were designed, constructed and operated through the 1980's). These early designs typically used alkaline leach chemistries in situ including use of ammonium carbonate which resulted in groundwater restoration challenges, open to air recovery vessels and high temperature calcining systems for final product drying vs the 'zero emissions' vacuum dryers as typically used today. Improved containment, automation and instrumentation control and use of vacuum dryers in the design of current generation plants are expected to reduce production of secondary waste byproduct material, reduce Radon emissions and reduce potential for employee exposure to uranium concentrate aerosols at the back end of the milling process. In Situ Recovery in the U.S. typically involves the circulation of groundwater, fortified with oxidizing (gaseous oxygen e.g) and complexing agents (carbon dioxide, e.g) into an ore body, solubilizing the uranium in situ, and then pumping the solutions to the surface where they are fed to a processing plant ( mill). Processing involves ion exchange and may also include precipitation, drying or calcining and packaging operations depending on facility specifics. This paper presents an overview of the ISR process and the health physics monitoring programs developed at a number of commercial scale ISL / ISR Uranium recovery and production facilities as a result of the radiological character of these processes. Although many radiological aspects of the process are similar to that of conventional mills, conventional-type tailings as such are not generated. However, liquid and solid byproduct materials may be generated and impounded. The quantity and radiological character of these by products are related to facility specifics. Some special monitoring considerations are presented which are required due to the manner in which radon gas is evolved in the process and the unique aspects of controlling solution flow patterns underground. The radiological character of these processes are described using empirical data collected from many operating facilities. Additionally, the major aspects of the health physics and radiation protection programs that were developed at these first generation facilities are discussed and contrasted to circumstances of the current generation and state of the art of uranium ISR technologies and facilities. In summary: This paper has presented an overview of in situ Uranium recovery processes and associated major radiological aspects and monitoring considerations. Admittedly, the purpose was to present an overview of those special health physics considerations dictated by the in situ Uranium recovery technology, to point out similarities and differences to conventional mill programs and to contrast these alkaline leach facilities to modern day ISR designs. As evidenced by the large number of ISR projects currently under development in the U.S. and worldwide, non conventional Uranium recovery techniques

  10. Intergranular fracture in UO2: derivation of traction-separation law from atomistic simulations

    SciTech Connect (OSTI)

    Yongfeng Zhang; Paul C Millett; Michael R Tonks; Xian-Ming Bai; S Bulent Biner

    2013-10-01T23:59:59.000Z

    In this study, the intergranular fracture behavior of UO2 was studied by molecular dynamics simulations using the Basak potential. In addition, the constitutive traction-separation law was derived from atomistic data using the cohesive-zone model. In the simulations a bicrystal model with the (100) symmetric tilt E5 grain boundaries was utilized. Uniaxial tension along the grain boundary normal was applied to simulate Mode-I fracture. The fracture was observed to propagate along the grain boundary by micro-pore nucleation and coalescence, giving an overall intergranular fracture behavior. Phase transformations from the Fluorite to the Rutile and Scrutinyite phases were identified at the propagating crack tips. These new phases are metastable and they transformed back to the Fluorite phase at the wake of crack tips as the local stress concentration was relieved by complete cracking. Such transient behavior observed at atomistic scale was found to substantially increase the energy release rate for fracture. Insertion of Xe gas into the initial notch showed minor effect on the overall fracture behavior.

  11. Interface control document between PUREX/UO{sub 3} Plant Transition and Solid Waste Disposal Division

    SciTech Connect (OSTI)

    Duncan, D.R.

    1994-06-30T23:59:59.000Z

    This interface control document (ICD) between PUREX/UO{sub 3} Plant Transition (PPT) and Solid Waste Disposal Division (SWD) establishes at a top level the functional responsibilities of each division where interfaces exist between the two divisions. Since the PUREX Transition and Solid Waste Disposal divisions operate autonomously, it is important that each division has a clear understanding of the other division`s expectations regarding these interfaces. This ICD primarily deals with solid wastes generated by the PPT. In addition to delineating functional responsibilities, the ICD includes a baseline description of those wastes that will require management as part of the interface between the divisions. The baseline description of wastes includes waste volumes and timing for use in planning the proper waste management capabilities: the primary purpose of this ICD is to ensure defensibility of expected waste stream volumes and Characteristics for future waste management facilities. Waste descriptions must be as complete as-possible to ensure adequate treatment, storage, and disposal capability will exist. The ICD also facilitates integration of existing or planned waste management capabilities of the PUREX. Transition and Solid Waste Disposal divisions. The ICD does not impact or affect the existing processes or procedures for shipping, packaging, or approval for shipping wastes by generators to the Solid Waste Division.

  12. Molecular dynamics simulations of intergranular fracture in UO2 with nine empirical interatomic potentials

    SciTech Connect (OSTI)

    Yongfeng Zhang; Paul C Millett; Michael R Tonks; Xian-Ming Bai; S Bulent Biner

    2014-09-01T23:59:59.000Z

    The intergranular fracture behavior of UO2 was studied using molecular dynamics simulations with a bicrystal model. The anisotropic fracture behavior due to the different grain boundary characters was investigated with the View the MathML source symmetrical tilt S5 and the View the MathML source symmetrical tilt S3 ({1 1 1} twin) grain boundaries. Nine interatomic potentials, seven rigid-ion plus two core–shell ones, were utilized to elucidate possible potential dependence. Initiating from a notch, crack propagation along grain boundaries was observed for most potentials. The S3 boundary was found to be more prone to fracture than the S5 one, indicated by a lower energy release rate associated with the former. However, some potential dependence was identified on the existence of transient plastic deformation at crack tips, and the results were discussed regarding the relevant material properties including the excess energies of metastable phases and the critical energy release rate for intergranular fracture. In general, local plasticity at crack tips was observed in fracture simulations with potentials that predict low excess energies for metastable phases and high critical energy release rates for intergranular fracture.

  13. Graphite and Beryllium Reflector Critical Assemblies of UO2 (Benchmark Experiments 2 and 3)

    SciTech Connect (OSTI)

    Margaret A. Marshall; John D. Bess

    2012-11-01T23:59:59.000Z

    INTRODUCTION A series of experiments was carried out in 1962-65 at the Oak Ridge National Laboratory Critical Experiments Facility (ORCEF) for use in space reactor research programs. A core containing 93.2 wt% enriched UO2 fuel rods was used in these experiments. The first part of the experimental series consisted of 252 tightly-packed fuel rods (1.27-cm triangular pitch) with graphite reflectors [1], the second part used 252 graphite-reflected fuel rods organized in a 1.506-cm triangular-pitch array [2], and the final part of the experimental series consisted of 253 beryllium-reflected fuel rods in a 1.506-cm-triangular-pitch configuration and in a 7-tube-cluster configuration [3]. Fission rate distribution and cadmium ratio measurements were taken for all three parts of the experimental series. Reactivity coefficient measurements were taken for various materials placed in the beryllium reflected core. All three experiments in the series have been evaluated for inclusion in the International Reactor Physics Experiment Evaluation Project (IRPhEP) [4] and the International Criticality Safety Benchmark Evaluation Project (ICSBEP) Handbooks, [5]. The evaluation of the first experiment in the series was discussed at the 2011 ANS Winter meeting [6]. The evaluations of the second and third experiments are discussed below. These experiments are of interest as benchmarks because they support the validation of compact reactor designs with similar characteristics to the design parameters for a space nuclear fission surface power systems [7].

  14. 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. ...

  15. 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

  16. Carbon Dioxide Emission Factors for Coal

    Reports and Publications (EIA)

    1994-01-01T23:59:59.000Z

    The Energy Information Administration (EIA) has developed factors for estimating the amount of carbon dioxide emitted, accounting for differences among coals, to reflect the changing "mix" of coal in U.S. coal consumption.

  17. Regulating carbon dioxide capture and storage

    E-Print Network [OSTI]

    De Figueiredo, Mark A.

    2007-01-01T23:59:59.000Z

    This essay examines several legal, regulatory and organizational issues that need to be addressed to create an effective regulatory regime for carbon dioxide capture and storage ("CCS"). Legal, regulatory, and organizational ...

  18. 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...

  19. 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.

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

    E-Print Network [OSTI]

    Boyer, Edmond

    L'URANIUM ET LES ARMES Ć? L'URANIUM APPAUVRI. Pierre Roussel* Institut de Physique NuclĆ©aire, CNRS massivement dans la guerre du Golfe, des obus anti- chars ont Ć©tĆ© utilisĆ©s, avec des "charges d'uranium, avec une charge de 300 g d'uranium et tirĆ© par des avions, l'autre de 120 mm de diamĆØtre avec une

  1. 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...

  2. 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...

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. 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...

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. The Fabrication of Titanium Dioxide Based Anode Material Using Aerosol Method

    E-Print Network [OSTI]

    Zhao, Lin

    2013-01-01T23:59:59.000Z

    synthesis of graphene-based titanium dioxide nanocompositesLos Angeles The Fabrication of Titanium Dioxide Based AnodeTHE THESIS The Fabrication of Titanium Dioxide Based Anode

  13. Pressure buildup during supercritical carbon dioxide injection from a partially penetrating borehole into gas reservoirs

    E-Print Network [OSTI]

    Mukhopadhyay, S.

    2013-01-01T23:59:59.000Z

    the physical properties of carbon dioxide, compare thei.e. , Physical Properties of Carbon Dioxide Z ? PV ? 1 ?Thermophysical Properties of Carbon Dioxide, Publishing

  14. THE KINETICS OF LASER PULSE VAPORIZATION OF URANIUM DIOXIDE BY MASS SPECTROMETRY

    E-Print Network [OSTI]

    Tsai, Chuen-horng

    2012-01-01T23:59:59.000Z

    Core Disassembly Process in Fast Reactors," SJ-206-76-25 Tr,Computer Program for Fast-reactor Power Excursions," ANL-of Hypothetical Fast Breeder Reactor Accidents, IWGFR/26,

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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:...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. WIMS/PANTHER analysis of UO{sub 2}/MOX cores using embedded super-cells

    SciTech Connect (OSTI)

    Knight, M.; Bryce, P. [EDF Energy, Barnett Way, Barnwood, Gloucester (United Kingdom); Hall, S. [Advanced Modelling and Computation Group, Imperial College, London (United Kingdom)

    2012-07-01T23:59:59.000Z

    This paper describes a method of analysing PWR UO{sub 2}MOX cores with WIMS/PANTHER. Embedded super-cells, run within the reactor code, are used to correct the standard methodology of using 2-group smeared data from single assembly lattice calculations. In many other codes the weakness of this standard approach has been improved for MOX by imposing a more realistic environment in the lattice code, or by improving the sophistication of the reactor code. In this approach an intermediate set of calculations is introduced, leaving both lattice and reactor calculations broadly unchanged. The essence of the approach is that the whole core is broken down into a set of 'embedded' super-cells, each extending over just four quarter assemblies, with zero leakage imposed at the assembly mid-lines. Each supercell is solved twice, first with a detailed multi-group pin-by-pin solution, and then with the standard single assembly approach. Correction factors are defined by comparing the two solutions, and these can be applied in whole core calculations. The restriction that all such calculations are modelled with zero leakage means that they are independent of each other and of the core-wide flux shape. This allows parallel pre-calculation for the entire cycle once the loading pattern has been determined, in much the same way that single assembly lattice calculations can be pre-calculated once the range of fuel types is known. Comparisons against a whole core pin-by-pin reference demonstrates that the embedding process does not introduce a significant error, even after burnup and refuelling. Comparisons against a WIMS reference demonstrate that a pin-by-pin multi-group diffusion solution is capable of capturing the main interface effects. This therefore defines a practical approach for achieving results close to lattice code accuracy, but broadly at the cost of a standard reactor calculation. (authors)

  13. 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.

  14. NEUTRONICS STUDIES OF URANIUM-BASED FULLY CERAMIC MICRO-ENCAPSULATED FUEL FOR PWRs

    SciTech Connect (OSTI)

    George, Nathan M [ORNL; Maldonado, G Ivan [ORNL; Terrani, Kurt A [ORNL; Gehin, Jess C [ORNL; Godfrey, Andrew T [ORNL

    2012-01-01T23:59:59.000Z

    This study evaluates the core neutronics and fuel cycle characteristics that result from employing uranium-based fully ceramic micro-encapsulated (FCM) fuel in a pressurized water reactor (PWR). Specific PWR bundle designs with FCM fuel have been developed, which by virtue of their TRISO particle based elements, are expected to safely reach higher fuel burnups while also increasing the tolerance to fuel failures. The SCALE 6.1 code package, developed and maintained at ORNL, was the primary software employed to model these designs. Analysis was performed using the SCALE double-heterogeneous (DH) fuel modeling capabilities. For cases evaluated with the NESTLE full-core three-dimensional nodal simulator, because the feature to perform DH lattice physics branches with the SCALE/TRITON sequence is not yet available, the Reactivity-Equivalent Physical Transformation (RPT) method was used as workaround to support the full core analyses. As part of the fuel assembly design evaluations, fresh feed lattices were modeled to analyze the within-assembly pin power peaking. Also, a color-set array of assemblies was constructed to evaluate power peaking and power sharing between a once-burned and a fresh feed assembly. In addition, a parametric study was performed by varying the various TRISO particle design features; such as kernel diameter, coating layer thicknesses, and packing fractions. Also, other features such as the selection of matrix material (SiC, Zirconium) and fuel rod dimensions were perturbed. After evaluating different uranium-based fuels, the higher physical density of uranium mononitride (UN) proved to be favorable, as the parametric studies showed that the FCM particle fuel design will need roughly 12% additional fissile material in comparison to that of a standard UO2 rod in order to match the lifetime of an 18-month PWR cycle. Neutronically, the FCM fuel designs evaluated maintain acceptable design features in the areas of fuel lifetime, temperature coefficients of reactivity, as well as pin cell and assembly peaking factors. Key Words: FCM, TRISO, Uranium Mononitride, PWR

  15. 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

  16. 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.

  17. 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.

  18. Enhanced Generic Phase-field Model of Irradiation Materials: Fission Gas Bubble Growth Kinetics in Polycrystalline UO2

    SciTech Connect (OSTI)

    Li, Yulan; Hu, Shenyang Y.; Montgomery, Robert O.; Gao, Fei; Sun, Xin

    2012-05-30T23:59:59.000Z

    Experiments show that inter-granular and intra-granular gas bubbles have different growth kinetics which results in heterogeneous gas bubble microstructures in irradiated nuclear fuels. A science-based model predicting the heterogeneous microstructure evolution kinetics is desired, which enables one to study the effect of thermodynamic and kinetic properties of the system on gas bubble microstructure evolution kinetics and morphology, improve the understanding of the formation mechanisms of heterogeneous gas bubble microstructure, and provide the microstructure to macroscale approaches to study their impact on thermo-mechanical properties such as thermo-conductivity, gas release, volume swelling, and cracking. In our previous report 'Mesoscale Benchmark Demonstration, Problem 1: Mesoscale Simulations of Intra-granular Fission Gas Bubbles in UO2 under Post-irradiation Thermal Annealing', we developed a phase-field model to simulate the intra-granular gas bubble evolution in a single crystal during post-irradiation thermal annealing. In this work, we enhanced the model by incorporating thermodynamic and kinetic properties at grain boundaries, which can be obtained from atomistic simulations, to simulate fission gas bubble growth kinetics in polycrystalline UO2 fuels. The model takes into account of gas atom and vacancy diffusion, vacancy trapping and emission at defects, gas atom absorption and resolution at gas bubbles, internal pressure in gas bubbles, elastic interaction between defects and gas bubbles, and the difference of thermodynamic and kinetic properties in matrix and grain boundaries. We applied the model to simulate gas atom segregation at grain boundaries and the effect of interfacial energy and gas mobility on gas bubble morphology and growth kinetics in a bi-crystal UO2 during post-irradiation thermal annealing. The preliminary results demonstrate that the model can produce the equilibrium thermodynamic properties and the morphology of gas bubbles at grain boundaries for given grain boundary properties. More validation of the model capability in polycrystalline is underway.

  19. Carbon dioxide capture process with regenerable sorbents

    DOE Patents [OSTI]

    Pennline, Henry W. (Bethel Park, PA); Hoffman, James S. (Library, PA)

    2002-05-14T23:59:59.000Z

    A process to remove carbon dioxide from a gas stream using a cross-flow, or a moving-bed reactor. In the reactor the gas contacts an active material that is an alkali-metal compound, such as an alkali-metal carbonate, alkali-metal oxide, or alkali-metal hydroxide; or in the alternative, an alkaline-earth metal compound, such as an alkaline-earth metal carbonate, alkaline-earth metal oxide, or alkaline-earth metal hydroxide. The active material can be used by itself or supported on a substrate of carbon, alumina, silica, titania or aluminosilicate. When the active material is an alkali-metal compound, the carbon-dioxide reacts with the metal compound to generate bicarbonate. When the active material is an alkaline-earth metal, the carbon dioxide reacts with the metal compound to generate carbonate. Spent sorbent containing the bicarbonate or carbonate is moved to a second reactor where it is heated or treated with a reducing agent such as, natural gas, methane, carbon monoxide hydrogen, or a synthesis gas comprising of a combination of carbon monoxide and hydrogen. The heat or reducing agent releases carbon dioxide gas and regenerates the active material for use as the sorbent material in the first reactor. New sorbent may be added to the regenerated sorbent prior to subsequent passes in the carbon dioxide removal reactor.

  20. 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...

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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

  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 Uranium9117 20145

  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 Uranium9117

  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 MDomesticDomestic Uranium

  15. 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

  16. 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.

  17. 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

  18. 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

  19. 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.

  20. Atomistic Calculations of the Effect of Minor Actinides on Thermodynamic and Kinetic Properties of UO{sub 2{+-}x}

    SciTech Connect (OSTI)

    Deo, Chaitanya; Adnersson, Davis; Battaile, Corbett; uberuaga, Blas

    2012-10-30T23:59:59.000Z

    The team will examine how the incorporation of actinide species important for mixed oxide (MOX) and other advanced fuel designs impacts thermodynamic quantities of the host UO{sub 2} nuclear fuel and how Pu, Np, Cm and Am influence oxygen mobility. In many cases, the experimental data is either insufficient or missing. For example, in the case of pure NpO2, there is essentially no experimental data on the hyperstoichiometric form it is not even known if hyperstoichiometry NpO{sub 2{+-}x} is stable. The team will employ atomistic modeling tools to calculate these quantities

  1. Improving Natural Uranium Utilization By Using Thorium in Low Moderation PWRs - A Preliminary Neutronic Scoping Study

    SciTech Connect (OSTI)

    Gilles Youinou; Ignacio Somoza

    2010-10-01T23:59:59.000Z

    The Th-U fuel cycle is not quite self-sustainable when used in water-cooled reactors and with fuel burnups higher than a few thousand of MWd/t characteristic of CANDU reactors operating with a continuous refueling. For the other industrially mature water-cooled reactors (i.e. PWRs and BWRs) it is economically necessary that the fuel has enough reactivity to reach fuel burnups of the order of a few tens of thousand of MWd/t. In this particular case, an additional input of fissile material is necessary to complement the bred fissile U-233. This additional fissile material could be included in the form of Highly Enriched Uranium (HEU) at the fabrication of the Th-U fuel. The objective of this preliminary neutronic scoping study is to determine (1) how much HEU and, consequently, how much natural uranium is necessary in such Th-U fuel cycle with U recycling and (2) how much TRansUranics (TRU=Pu, Np, Am and Cm) are produced. These numbers are then compared with those of a standard UO2 PWR. The thorium reactors considered have a homogeneous hexagonal lattice made up of the same (Th-U)O2 pins. Furthermore, at this point, we are not considering the use of blankets inside or outside the core. The lattice pitch has been varied to estimate the effect of the water-to-fuel volume ratio, and light water as well as heavy water have been considered. For most cases, an average burnup at discharge of 45,000 MWd/t has been considered.

  2. Genome-Based Models to Optimize In Situ Bioremediation of Uranium and Harvesting Electrical Energy from Waste Organic Matter

    SciTech Connect (OSTI)

    Lovley, Derek R

    2012-12-28T23:59:59.000Z

    The goal of this research was to provide computational tools to predictively model the behavior of two microbial communities of direct relevance to Department of Energy interests: 1) the microbial community responsible for in situ bioremediation of uranium in contaminated subsurface environments; and 2) the microbial community capable of harvesting electricity from waste organic matter and renewable biomass. During this project the concept of microbial electrosynthesis, a novel form of artificial photosynthesis for the direct production of fuels and other organic commodities from carbon dioxide and water was also developed and research was expanded into this area as well.

  3. 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.

  4. 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.

  5. Modified biokinetic model for uranium from analysis of acute exposure to UF6

    SciTech Connect (OSTI)

    Fisher, D.R.; Kathren, R.L.; Swint, M.J. (Pacific Northwest Laboratory, Richland, WA (USA))

    1991-03-01T23:59:59.000Z

    Urinalysis measurements from 31 workers acutely exposed to uranium hexafluoride (UF6) and its hydrolysis product UO2F2 (during the 1986 Gore, Oklahoma UF6-release accident) were used to develop a modified recycling biokinetic model for soluble U compounds. The model is expressed as a five-compartment exponential equation: yu(t) = 0.086e-2.77t + 0.0048e-0.116t + 0.00069e-0.0267t + 0.00017 e-0.00231t + 2.5 x 10(-6) e-0.000187t, where yu(t) is the fractional daily urinary excretion and t is the time after intake, in days. The excretion constants of the five exponential compartments correspond to residence half-times of 0.25, 6, 26, 300, and 3,700 d in the lungs, kidneys, other soft tissues, and in two bone volume compartments, respectively. The modified recycling model was used to estimate intake amounts, the resulting committed effective dose equivalent, maximum kidney concentrations, and dose equivalent to bone surfaces, kidneys, and lungs.

  6. Preconcentration of uranium in seawater with heterocyclic azo dyes supported on silica gel

    SciTech Connect (OSTI)

    Ueda, K.; Koshino, Y.; Yamamoto, Y.

    1985-11-01T23:59:59.000Z

    The chelating adsorbents, heterocyclic azo dyes supported on silica gel, were prepared and their adsorption behaviors of metal ions were investigated. The 1-(2-pyridylazo)-2-naphthol(PAN)-SG and 2-(2-thiazolylazo)-p-cresol(TAC)-SG show greater affinity for UO/sub 2/(II) and ZrO(II), compared with the other metal ions like Cu, Cd, Fe and alkaline earths. Trace uranyl can be quantitatively retained on the column of the gels at neutral pH region and flowrate 3-4 ml/min. The uranyl retained is easily eluted from the column bed with a mixture of acetone and nitric acid (9:1 v/v) and determined by spectrophotometry using Arsenazo-III. Matrix components in seawater do not interfere and the spiked recovery of uranyl in artificial seawater was found to be average 98.6%, with the relative standard deviation of 1.08%. Both gels were applied to the determination of uranium in seawater with satisfactory results. 16 references, 3 figures, 3 tables.

  7. MESOSCALE BIOTRANSFORMATIONS OF URANIUM IN SEDIMENTS AND SOILS (Program Element: Biogeochemistry)

    SciTech Connect (OSTI)

    Tetsu Tokunaga; Jiamin Wan; Brodic, Eoin; Yongman Kim; Hazen, Terry; Firestone, Mary; Herman, Don; Sutton, Steve; Newville, Matt; Lanzirotti, Tony, Rao, Bill

    2006-04-05T23:59:59.000Z

    In-situ bioreduction is being considered as a remediation strategy for uranium (U) contaminated sediments because of its potentially low cost, and because short-term studies support its feasibility. However, any in-situ approach for immobilizing U will require assurance of either permanent fixation, or of very low release rates into the biosphere. Our long-term laboratory studies have shown that reoxidation of bioreduced UO{sub 2} can occur even under reducing (methanogenic) conditions sustained by continuous infusion of lactate. The biogeochemical processes underlying this finding need to be understood. Our current research is designed to identify mechanisms responsible for anaerobic U oxidation, and identify effects of key factors controlling long-term stability of bioreduced U. These include: (1) effects of organic carbon (OC) concentrations and supply rates on stability of bioreduced U, (2) influences of pH on U(IV)/U(VI) redox equilibrium, (3) the roles of Fe- and Mn-oxides as potential U oxidants in sediments, and (4) the role of microorganisms in U reoxidation. Findings from some of these studies are summarized here.

  8. SEQUESTERING CARBON DIOXIDE IN COALBEDS

    SciTech Connect (OSTI)

    K.A.M. Gasem; R.L. Robinson, Jr.; J.E. Fitzgerald; Z. Pan; M. Sudibandriyo

    2003-04-30T23:59:59.000Z

    The authors' long-term goal is to develop accurate prediction methods for describing the adsorption behavior of gas mixtures on solid adsorbents over complete ranges of temperature, pressure, and adsorbent types. The originally-stated, major objectives of the current project are to: (1) measure the adsorption behavior of pure CO{sub 2}, methane, nitrogen, and their binary and ternary mixtures on several selected coals having different properties at temperatures and pressures applicable to the particular coals being studied, (2) generalize the adsorption results in terms of appropriate properties of the coals to facilitate estimation of adsorption behavior for coals other than those studied experimentally, (3) delineate the sensitivity of the competitive adsorption of CO{sub 2}, methane, and nitrogen to the specific characteristics of the coal on which they are adsorbed; establish the major differences (if any) in the nature of this competitive adsorption on different coals, and (4) test and/or develop theoretically-based mathematical models to represent accurately the adsorption behavior of mixtures of the type for which measurements are made. As this project developed, an important additional objective was added to the above original list. Namely, we were encouraged to interact with industry and/or governmental agencies to utilize our expertise to advance the state of the art in coalbed adsorption science and technology. As a result of this additional objective, we participated with the Department of Energy and industry in the measurement and analysis of adsorption behavior as part of two distinct investigations. These include (a) Advanced Resources International (ARI) DOE Project DE-FC26-00NT40924, ''Adsorption of Pure Methane, Nitrogen, and Carbon Dioxide and Their Mixtures on Wet Tiffany Coal'', and (b) the DOE-NETL Project, ''Round Robin: CO{sub 2} Adsorption on Selected Coals''. These activities, contributing directly to the DOE projects listed above, also provided direct synergism with the original goals of our work. Specific accomplishments of this project are summarized below in three broad categories: experimentation, model development, and coal characterization.

  9. A methodology for forecasting carbon dioxide flooding performance

    E-Print Network [OSTI]

    Marroquin Cabrera, Juan Carlos

    1998-01-01T23:59:59.000Z

    A methodology was developed for forecasting carbon dioxide (CO2) flooding performance quickly and reliably. The feasibility of carbon dioxide flooding in the Dollarhide Clearfork "AB" Unit was evaluated using the methodology. This technique is very...

  10. Carbon Dioxide Capture/Sequestration Tax Deduction (Kansas)

    Broader source: Energy.gov [DOE]

    Carbon Dioxide Capture/Sequestration Tax Deduction allows a taxpayer a deduction to adjusted gross income with respect to the amortization of the amortizable costs of carbon dioxide capture,...

  11. Louisiana Geologic Sequestration of Carbon Dioxide Act (Louisiana)

    Broader source: Energy.gov [DOE]

    This law establishes that carbon dioxide and sequestration is a valuable commodity to the citizens of the state. Geologic storage of carbon dioxide may allow for the orderly withdrawal as...

  12. High-Efficiency Receivers for Supercritical Carbon Dioxide Cycles...

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

    Receivers for Supercritical Carbon Dioxide Cycles - FY12 Q4 High-Efficiency Receivers for Supercritical Carbon Dioxide Cycles - FY12 Q4 This document summarizes the progress of...

  13. 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

  14. 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 (Me2PzĄ ) led to forma- tion of an unprecedented homoleptic

  15. D10 experiment: coolability of UO/sub 2/ debris in sodium with downward heat removal. [LMFBR

    SciTech Connect (OSTI)

    Mitchell, G.W.; Ottinger, C.A.; Meister, H.

    1984-12-01T23:59:59.000Z

    The LMFBR Debris Coolability Program at Sandia National Laboratories investigates the coolability of particle beds which may form following a severe accident involving core disassembly in a nuclear reactor. The D series experiments utilize fission heating of fully enriched UO/sub 2/ particles submerged in sodium to realistically simulate decay heating. The D10 experiment is the first in the series to study the effects of bottom cooling of the debris that could be provided in an actual accident condition by structural materials onto which the debris might settle. Additionally, the D10 experiment was designed to achieve maximum temperatures in the debris approaching the melting point of UO/sub 2/. The experiment was successfully operated for over 50 hours and investigated downward heat removal in a packed bed at specific powers of 0.16 to 0.58 W/g. Dryout in the debris was achieved at powers from 0.42 to 0.58 W/g. Channels were induced in the bed and channeled bed dryout was achieved at powers of 1.06 to 1.77 W/g. Maximum temperatures in excess of 2500/sup 0/C were attained.

  16. Microstructure changes and thermal conductivity reduction in UO2 following 3.9 MeV He2+ ion irradiation

    SciTech Connect (OSTI)

    Janne Pakrinen; Marat Khafizov; Lingfeng He; Chris Wetland; Jian Gan; Andrew T. Nelson; David H Hurley; Anter El-Azab; Todd R Allen

    2014-11-01T23:59:59.000Z

    The microstructural changes and associated effects on thermal conductivity were examined in UO2 after irradiation using 3.9 MeV He2+ ions. Lattice expansion of UO2 was observed in x-ray diffraction after ion irradiation up to 5×1016 He2+/cm2 at low-temperature (< 200 °C). Transmission electron microscopy (TEM) showed homogenous irradiation damage across an 8 µm thick plateau region, which consisted of small dislocation loops accompanied by dislocation segments. Dome-shaped blisters were observed at the peak damage region (depth around 8.5 µm) in the sample subjected to 5×1016 He2+/cm2, the highest fluence reached, while similar features were not detected at 9×1015 He2+/cm2. Laser-based thermo-reflectance measurements showed that the thermal conductivity for the irradiated layer decreased about 55 % for the high fluence sample and 35% for the low fluence sample as compared to an un-irradiated reference sample. Detailed analysis for the thermal conductivity indicated that the conductivity reduction was caused by the irradiation induced point defects.

  17. Coolability of stratified UO/sub 2/ debris in sodium with downward heat removal: The D13 experiment

    SciTech Connect (OSTI)

    Ottinger, C.A.; Mitchell, G.W.; Reed, A.W.; Meister, H.

    1987-03-01T23:59:59.000Z

    The LMFBR Debris Coolability Program at Sandia National Laboratories investigates the coolability of particle beds that may form following a severe accident involving core disassembly in a nuclear reactor. The D series experiments utilize fission heating of fully enriched UO/sub 2/ particles submerged in sodium to realistically simulate decay heating. The D13 experiment is the first in the series to study the effects of bottom cooling of stratified debris, which could be provided in an actual accident condition by structural materials onto which the debris might settle. Additionally, the D13 experiment was designed to achieve maximum temperatures in the debris approaching the melting point of UO/sub 2/. The experiment was operated for over 40 hours and investigated downward heat removal at specific powers of 0.22 to 2.58 W/g. Channeled dryout in the debris was achieved at powers from 0.94 to 2.58 W/g. Maximum temperatures approaching 2700/sup 0/C were attained. Bottom heat removal was up to 750 kW/m/sup 2/ as compared to 450 kW/m/sup 2/ in the D10 experiment.

  18. Designed amyloid fibers as materials for selective carbon dioxide capture

    E-Print Network [OSTI]

    Designed amyloid fibers as materials for selective carbon dioxide capture Dan Lia,b,c,1 , Hiroyasu demonstrate that amyloids, self-assembling protein fibers, are effective for selective carbon dioxide capture formation rate is fast enough to capture carbon dioxide by dynamic separation, undiminished by the presence

  19. Glutamate Surface Speciation on Amorphous Titanium Dioxide and

    E-Print Network [OSTI]

    Sverjensky, Dimitri A.

    Glutamate Surface Speciation on Amorphous Titanium Dioxide and Hydrous Ferric Oxide D I M I T R I (HFO) and titanium dioxide exhibit similar strong attachment of many adsorbates including biomolecules on amorphous titanium dioxide. The results indicate that glutamate adsorbs on HFO as a deprotonated divalent

  20. Nanostructured Tin Dioxide Materials for Gas Sensor Applications

    E-Print Network [OSTI]

    Wooldridge, Margaret S.

    CHAPTER 30 Nanostructured Tin Dioxide Materials for Gas Sensor Applications T. A. Miller, S. D) levels for some species. Tin dioxide (also called stannic oxide or tin oxide) semi- conductor gas sensors undergone extensive research and development. Tin dioxide (SnO2) is the most important material for use

  1. Thermal Properties of Supercritical Carbon Dioxide by Monte Carlo Simulations

    E-Print Network [OSTI]

    Lisal, Martin

    Thermal Properties of Supercritical Carbon Dioxide by Monte Carlo Simulations C.M. COLINAa,b, *, C and speed of sound for carbon dioxide (CO2) in the supercritical region, using the fluctuation method based: Fluctuations; Carbon dioxide; 2CLJQ; Joule­Thomson coefficient; Speed of sound INTRODUCTION Simulation methods

  2. Array of titanium dioxide nanostructures for solar energy utilization

    DOE Patents [OSTI]

    Qiu, Xiaofeng; Parans Paranthaman, Mariappan; Chi, Miaofang; Ivanov, Ilia N; Zhang, Zhenyu

    2014-12-30T23:59:59.000Z

    An array of titanium dioxide nanostructures for solar energy utilization includes a plurality of nanotubes, each nanotube including an outer layer coaxial with an inner layer, where the inner layer comprises p-type titanium dioxide and the outer layer comprises n-type titanium dioxide. An interface between the inner layer and the outer layer defines a p-n junction.

  3. Chukwuemeka I. Okoye Carbon Dioxide Solubility and Absorption Rate in

    E-Print Network [OSTI]

    Rochelle, Gary T.

    Copyright by Chukwuemeka I. Okoye 2005 #12;Carbon Dioxide Solubility and Absorption Rate _______________________ Nicholas A. Peppas #12;Carbon Dioxide Solubility and Absorption Rate in Monoethanolamine/Piperazine/H2O for. #12;iii Carbon Dioxide Solubility and Absorption Rate in Monoethanolamine/Piperazine/H2O

  4. Standard test method for determination of impurities in plutonium: acid dissolution, ion exchange matrix separation, and inductively coupled plasma-atomic emission spectroscopic (ICP/AES) analysis

    E-Print Network [OSTI]

    American Society for Testing and Materials. Philadelphia

    2003-01-01T23:59:59.000Z

    1.1 This specification covers blended uranium trioxide (UO3), U3O8, or mixtures of the two, powders that are intended for conversion into a sinterable uranium dioxide (UO2) powder by means of a direct reduction process. The UO2 powder product of the reduction process must meet the requirements of Specification C 753 and be suitable for subsequent UO2 pellet fabrication by pressing and sintering methods. This specification applies to uranium oxides with a 235U enrichment less than 5 %. 1.2 This specification includes chemical, physical, and test method requirements for uranium oxide powders as they relate to the suitability of the powder for storage, transportation, and direct reduction to UO2 powder. This specification is applicable to uranium oxide powders for such use from any source. 1.3 The scope of this specification does not comprehensively cover all provisions for preventing criticality accidents, for health and safety, or for shipping. Observance of this specification does not relieve the user of th...

  5. 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.

  6. 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,

  7. 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

  8. 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

  9. 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. (

  10. 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

  11. 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

  12. 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

  13. 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.

  14. 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, (

  15. 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

  16. 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.

  17. Carbon Dioxide Capture from Coal-Fired

    E-Print Network [OSTI]

    Carbon Dioxide Capture from Coal-Fired Power Plants: A Real Options Analysis May 2005 MIT LFEE 2005. LFEE 2005-002 Report #12;#12;i ABSTRACT Investments in three coal-fired power generation technologies environment. The technologies evaluated are pulverized coal (PC), integrated coal gasification combined cycle

  18. Carbon Dioxide Corrosion: Modelling and Experimental Work

    E-Print Network [OSTI]

    Carbon Dioxide Corrosion: Modelling and Experimental Work Applied to Natural Gas Pipelines Philip in the corrosion related research institutions at IFE and the Ohio University or any other scientific research;#12;Introduction - v - Summary CO2 corrosion is a general problem in the industry and it is expensive. The focus

  19. Atmospheric Lifetime of Fossil Fuel Carbon Dioxide

    E-Print Network [OSTI]

    Scherer, Norbert F.

    Atmospheric Lifetime of Fossil Fuel Carbon Dioxide David Archer,1 Michael Eby,2 Victor Brovkin,3 released from combustion of fossil fuels equilibrates among the various carbon reservoirs of the atmosphere literature on the atmospheric lifetime of fossil fuel CO2 and its impact on climate, and we present initial

  20. Carbon Dioxide Corrosion and Inhibition Studies

    E-Print Network [OSTI]

    Petta, Jason

    Ā· Corrosion inhibition very important in the oil industry Ā· Film forming inhibitors containing nitrogenCarbon Dioxide Corrosion and Inhibition Studies Kristin Gilida #12;Outline Ā· Background = Zreal + Zim Rp 1/Corr Rate #12;Tafel Ā· Measures corrosion rate directly Ā· Measures iCORR from A and C

  1. 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.

  2. 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...

  3. 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.

  4. 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.

  5. 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...

  6. 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 ...

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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...

  13. 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.

  14. 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...

  15. UO Department of Chemistry -Faculty Research Interests Berglund, Andy -The primary goals of the Berglund lab are to understand the molecular basis of the human disease myotonic

    E-Print Network [OSTI]

    Cina, Jeff

    measurement, and device fabrication to design, build and study new materials and structures that have applications in solar energy harvesting and electrochemical energy storage. Chartoff, Richard - The UO Polymer approach to the synthesis of extended solids that permits them to prepare families of new nanostructured

  16. Synthesis and structure of Cs[UO{sub 2}(SeO{sub 4})(OH)] . nH{sub 2}O (n = 1.5 or 1)

    SciTech Connect (OSTI)

    Serezhkina, L. B., E-mail: lserezh@ssu.samara.ru [Samara State University (Russian Federation); Peresypkina, E. V.; Virovets, A. V. [Russian Academy of Sciences, Institute of Inorganic Chemistry, Siberian Branch (Russian Federation); Pushkin, D. V.; Verevkin, A. G. [Samara State University (Russian Federation)

    2010-05-15T23:59:59.000Z

    The synthesis and single-crystal X-ray diffraction study of Cs[UO{sub 2}(SeO{sub 4})(OH)] . 1.5H{sub 2}O (I) and Cs[UO{sub 2}(SeO{sub 4})(OH)] . H{sub 2}O (II) are performed. Compound I crystallizes in the monoclinic crystal system, a = 7.2142(2) A, b = 14.4942(4) A, c = 8.9270(3) A, {beta} = 112.706(1){sup o}, space group P2{sub 1}/m, Z = 4, and R = 0.0222. Compound II is monoclinic, a = 8.4549(2) A, b = 11.5358(3) A, c = 9.5565(2) A, {beta} = 113.273(1){sup o}, space group P2{sub 1}/c, Z = 4, and R = 0.0219. The main structural units of crystals I and II are [UO{sub 2}(SeO{sub 4})(OH)]{sup -} layers which belong to the AT{sup 3}M{sup 2} crystal chemical group of uranyl complexes (A = UO{sub 2}{sup 2+}, T{sup 3} = SeO{sub 4}{sup 2-}, and M{sup 2} = OH{sup -}). In structure I, johannite-like layers are found. Structure II is a topological isomer of I. The two structures differ in the number of U(VI) atoms bound to the central atom by all bridging ligands.

  17. Possible Bose-condensated Behavior in a Quantum Phase Originating in a Collective Excitation in the Chemically and Optically Doped Mott-Hubbard System UO2+x

    SciTech Connect (OSTI)

    Conradson, Steven D.; Durakiewicz, Tomasz; Espinosa-Faller, Francisco J.; An, Yong Q.; Andersson , David; Bishop, Alan R.; Boland, Kevin S.; Bradley, Joseph A.; Byler, Darrin D.; Clark, David L.; Conradson, Dylan R.; Conradson, Leilani L.; Costello, Alison E.; Hess, Nancy J.; Lander, Gerard H.; Llobet, Anna; Martucci, Mary B.; de Leon, Jose M.; Nordlund, Dennis; Lezama-Pacheco, Juan S.; Proffen, Thomas E.; Rodriguez, George; Schwarz, Daniel E.; Seidler, Gerald T.; Taylor, Antoinette; Trugman, Stuart A.; Tyson, Trevor A.; Valdez, James A.

    2013-09-23T23:59:59.000Z

    The pinned charge defects in U4O9, and U3O7 that are the single phase fluoritestructured derivatives of UO2 have been characterized by U L3 EXAFS at 30, 100, and 200 K, xray and neutron pair distribution function analysis, O K edge XAS and non-resonant inelastic xray scattering, and Raman spectroscopy, while mobile charge defects were investigated by femtosecond time-resolved pump-probe laser spectroscopy on single crystal UO2 between 7 and 300 K. The results from all of these measurements show highly complex and anomalous behaviors, which we attribute to a charge-lattice instability in UO2 that most likely originates in the intersection of the ground U(IV) and a proximate uranyl-like excited state in a conic section, causing a breakdown of the Born-Oppenheimer approximation. Furthermore, the photoinduced quasiparticles undergo a gap-opening condensation between 50 and 60 K. Doped UO2 may therefore exhibit novel correlated electron physics that extends beyond that of the cuprate-manganite-pnictide family of compounds.

  18. 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.

  19. 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/.

  20. 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.

  1. 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.

  2. Modeling the Distribution of Acidity within Nuclear Fuel (UO{sub 2}) Corrosion Product Deposits and Porous Sites

    SciTech Connect (OSTI)

    Cheong, W.J.; Keech, P.G.; Wren, J.C.; Shoesmith, D.W.; Qin, Z. [The University of Western Ontario, London, Ontario, N6A 5B7 (Canada)

    2007-07-01T23:59:59.000Z

    A model for acidity within pores within corrosion products on anodically-dissolving UO{sub 2} was developed using Comsol Multiphysics 3.2 to complement ongoing electrochemical measurements. It was determined that a depression of pH within pores can be maintained if: electrochemically measured dissolution currents used in the calculations are attenuated to reflect very localized pores; corrosion potentials exceed -250 mV (vs. SCE); and pore depths are >1 {mu}m for 300 mV or >100 {mu}m for -50 mV (vs. SCE). Mixed diffusional-chemical equilibria control is suggested through deviations in the shapes between pH-potential and pH-pore depth plots. (authors)

  3. 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

  4. 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

  5. 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

  6. Costs to reduce sulfur dioxide emissions

    SciTech Connect (OSTI)

    None

    1982-03-01T23:59:59.000Z

    Central to the resolution of the acid rain issue are debates about the costs and benefits of controlling man-made emissions of chemicals that may cause acid rain. In this briefing, the position of those who are calling for immediate action and implicating coal-fired powerplants as the cause of the problem is examined. The costs of controlling sulfur dioxide emissions using alternative control methods available today are presented. No attempt is made to calculate the benefits of reducing these emissions since insufficient information is available to provide even a rough estimate. Information is presented in two steps. First, costs are presented as obtained through straightforward calculations based upon simplifying but realistic assumptions. Next, the costs of sulfur dioxide control obtained through several large-scale analyses are presented, and these results are compared with those obtained through the first method.

  7. 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.

  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. 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.

  17. 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...

  18. 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

  19. 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

  20. New Materials for Capturing Carbon Dioxide from Combustion Gases

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

    to APS Science Highlights rss feed New Materials for Capturing Carbon Dioxide from Combustion Gases April 9, 2014 Bookmark and Share The SIFSIX materials in order of increasing...