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Sample records for helium isotope perspective

  1. Helium isotopes in geothermal systems- Iceland, The Geysers,...

    Open Energy Info (EERE)

    isotopes in geothermal systems- Iceland, The Geysers, Raft River and Steamboat Springs Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Helium...

  2. Compact hydrogen/helium isotope mass spectrometer

    DOE Patents [OSTI]

    Funsten, Herbert O.; McComas, David J.; Scime, Earl E.

    1996-01-01

    The compact hydrogen and helium isotope mass spectrometer of the present invention combines low mass-resolution ion mass spectrometry and beam-foil interaction technology to unambiguously detect and quantify deuterium (D), tritium (T), hydrogen molecule (H.sub.2, HD, D.sub.2, HT, DT, and T.sub.2), .sup.3 He, and .sup.4 He concentrations and concentration variations. The spectrometer provides real-time, high sensitivity, and high accuracy measurements. Currently, no fieldable D or molecular speciation detectors exist. Furthermore, the present spectrometer has a significant advantage over traditional T detectors: no confusion of the measurements by other beta-emitters, and complete separation of atomic and molecular species of equivalent atomic mass (e.g., HD and .sup.3 He).

  3. Helium isotopes and tectonics in southern Italy

    SciTech Connect (OSTI)

    Sano, Yuji; Wakita, Hiroshi ); Nuccio, M.P. ); Italiano, F.

    1989-06-01

    Geodynamic evolution of southern Italy can be understood within the framework of the Mediterranean-Alpine System. Subduction of a plate along the Sicily-Calabrian forearc under the Tyrrhenian Sea has been suggested by many geophysicists, although it is not yet confirmed and remains somewhat controversial. Helium isotope ratios provide useful information on the geotectonic structure of the region. The authors report here the {sup 3}H/{sup 4}He ratios of terrestrial gas samples from southern Italy. The observed {sup 3}He/{sup 4}He ratios are relatively high in the Eolian volcanic arc region and low in the other areas. Dichotomous explanations are presented. Firstly, volcanic arc-forearc hypothesis suggests the subduction along the Sicily-Calabrian forearc. Secondly, horizontal transport hypothesis is described based on the relationship between the ratios and radial distance from the recent spreading basin in Southern Tyrrhenian Sea.

  4. Isotope Effects and Helium Retention Behavior in Vanadium Tritide

    SciTech Connect (OSTI)

    Bowman, Jr., R. C.; Attalla, A.; Craft, B. D.

    1985-04-01

    The relaxation times of the H, T, and 3He nuclei have been measured in vanadium hydride and tritide samples. Substantial isotope effects in both the phase transition temperatures and diffusion parameters have been found. When compared to hydrides, the tritide samples have lower transition temperatures and faster mobilities. The differences in the occupancies of the interstitial sites are largely responsible for these isotope effects. Most of the helium atoms generated by tritium decay remain trapped in microscopic bubbles formed with the VTx lattice. Evidence is presented for the gradual growth of the helium bubbles over periods of hundreds of days.

  5. Helium Isotopes In Geothermal And Volcanic Gases Of The Western...

    Open Energy Info (EERE)

    isotope ratios in gases of thirty hot springs and geothermal wells and of five natural gas wells in the western United States show no relationship to regional conductive heat...

  6. A Helium Isotope Perspective On The Dixie Valley, Nevada, Hydrothermal...

    Open Energy Info (EERE)

    to drive and sustain extensional geothermal systems. (c) 2005 CNR. Published by Elsevier Ltd. All rights reserved. Authors B. M. Kennedy and M. C. van Soest Published Journal...

  7. Method and means of reducing erosion of components of plasma devices exposed to helium and hydrogen isotope radiation

    DOE Patents [OSTI]

    Kaminsky, Manfred S.; Das, Santosh K.; Rossing, Thomas D.

    1977-01-25

    Surfaces of components of plasma devices exposed to radiation by atoms or ions of helium or isotopes of hydrogen can be protected from damage due to blistering by shielding the surfaces with a structure formed by sintering a powder of aluminum or beryllium and its oxide or by coating the surfaces with such a sintered metal powder.

  8. Tunneling effects in the kinetics of helium and hydrogen isotopes desorption from single-walled carbon nanotube bundles

    SciTech Connect (OSTI)

    Danilchenko, B. A. Yaskovets, I. I.; Uvarova, I. Y.; Dolbin, A. V.; Esel'son, V. B.; Basnukaeva, R. M.; Vinnikov, N. A.

    2014-04-28

    The kinetics of desorption both helium isotopes and molecules of hydrogen and deuterium from open-ended or ?-irradiated single-walled carbon nanotube bundles was investigated in temperature range of 10300?K. The gases desorption rates obey the Arrhenius law at high temperatures, deviate from it with temperature reduction and become constant at low temperatures. These results indicate the quantum nature of gas outflow from carbon nanotube bundles. We had deduced the crossover temperature below which the quantum corrections to the effective activation energy of desorption become significant. This temperature follows linear dependence against the inverse mass of gas molecule and is consistent with theoretical prediction.

  9. Helium isotope study of geothermal features in Chile with field and laboratory data

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

    Dobson, Patrick

    Dobson, P.F., Kennedy, B.M., Reich, M., Sanchez, P., and Morata, D. (2013) Effects of volcanism, crustal thickness, and large scale faulting on the He isotope signatures of geothermal systems in Chile. Proceedings, 38th Workshop on Geothermal Reservoir Engineering, Stanford University, Feb. 11-13, 2013

  10. Helium isotope study of geothermal features in Chile with field and laboratory data

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

    Dobson, Patrick

    2013-02-11

    Dobson, P.F., Kennedy, B.M., Reich, M., Sanchez, P., and Morata, D. (2013) Effects of volcanism, crustal thickness, and large scale faulting on the He isotope signatures of geothermal systems in Chile. Proceedings, 38th Workshop on Geothermal Reservoir Engineering, Stanford University, Feb. 11-13, 2013

  11. Isotopes

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

    Office of Science » Nuclear Physics » Isotopes Isotopes Isotopes produced at Los Alamos National Laboratory are saving lives, advancing cutting-edge research and keeping the U.S. safe. Get Expertise Eva Birnbaum (505) 665-7167 Email Wolfgang Runde (505) 667-3350 Email Isotope Production and Applications isotopes Isotopes produced at IPF are critical for medical diagnosis and disease treatment. These positron emission tomography images were made possible using isotopes produced at LANL.

  12. Isotopes

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

    Eva Birnbaum (505) 665-7167 Email Wolfgang Runde (505) 667-3350 Email Isotope Production and Applications isotopes Isotopes produced at IPF are critical for medical diagnosis and ...

  13. The Other Helium Shortage Smart Telescopes Go Stargazing No-bang...

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

    ... Less well known, however, is a more severe shortage of the much rarer isotope helium-3. Essential for key scientific, medical, and national security applications, no one would ...

  14. Metal tritides helium emission

    SciTech Connect (OSTI)

    Beavis, L.C.

    1980-02-01

    Over the past several years, we have been measuring the release of helium from metal tritides (primarily erbium tritide). We find that qualitatively all tritides of interest to us behave the same. When they are first formed, the helium is released at a low rate that appears to be related to the amount of surface area which has access to the outside of the material (either film or bulk). For example, erbium tritide films initially release about 0.3% of the helium generated. Most tritide films emit helium at about this rate initially. At some later time, which depends upon the amount of helium generated, the parent occluding element and the degree of tritium saturation of the dihydride phase the helium emission changes to a new mode in which it is released at approximately the rate at which it is generated (for example, we measure this value to be approx. = .31 He/Er for ErT/sub 1/./sub 9/ films). If erbium ditritide is saturated beyond 1.9 T/Er, the critical helium/metal ratio decreases. For example, in bulk powders ErT/sub 2/./sub 15/ reaches critical release concentration at approx. = 0.03. Moderate elevation of temperature above room temperature has little impact on the helium release rate. It appears that the process may have approx. = 2 kcal/mol activation energy. The first helium formed is well bound. As the tritide ages, the helium is found in higher energy sites. Similar but less extensive measurements on scandium, titanium, and zirconium tritides are also described. Finally, the thermal desorption of erbium tritides of various ages from 50 days to 3154 days is discussed. Significant helium is desorbed along with the tritium in all but the youngest samples during thermodesorption.

  15. Helium Energy | Open Energy Information

    Open Energy Info (EERE)

    Energy Jump to: navigation, search Name: Helium Energy Place: Spain Sector: Renewable Energy Product: Spain-based renewable energy development company. References: Helium Energy1...

  16. Is solid helium a supersolid?

    SciTech Connect (OSTI)

    Hallock, Robert

    2015-05-15

    Recent experiments suggest that helium-4 atoms can flow through an experimental cell filled with solid helium. But that incompletely understood flow is quite different from the reported superfluid-like motion that so excited physicists a decade ago.

  17. Mass spectrometric helium analysis of solid and gas samples from cold-fusion type experiments

    SciTech Connect (OSTI)

    Oliver, B.M.

    1995-12-01

    A custom mass spectrometer system, operating in static mode, has been used to measure helium in both solid and gas samples front cold-fusion type experiments. The mass spectrometer is a 2-in. Radius, 60{degrees}, permanent angle magnet instrument with a single electron-multiplier collecting. Depending on the absolute levels of helium expected, the analysis are conducted by isotope dilution or by measuring absolute collector values. Solid samples are vaporized to ensure complete helium release. Prior to analysis, the fraction of sample gas to be analyzed is exposed to a series of physical and chemical getters, including room temperature Zr-Al alloy (SAES type 101) and liquid-nitrogen cooled activated charcoal. This is done to remove active gases and hydrogen isotopes which could interfere with the helium determinations. Generally, the analysis protocol is to analyze an equal or greater number of {open_quotes}controls{close_quotes} along with the samples to accurately characterize system background and reproducibility. Absolute sensitivity for the system is approximately 1 x 10{sup 9} atoms. Absolute accuracy is 1% or better for helium levels > 10{sup 11} atoms. With few exceptions, helium analysis of solid samples front cold fusion type experiments have yielded no excess helium above usual system background. A few samples have shown helium levels in the low 10{sup 9} atom range, and some gas samples have shown {sup 4}He levels up to several hundred ppm.

  18. Isotopic Analysis- Fluid At Dixie Valley Geothermal Area (Kennedy...

    Open Energy Info (EERE)

    suggest that helium isotopes are the best and possibly the only indication of deep permeability where high temperature fluids are masked beneath a cold reservoir. Notes 3He4He...

  19. Isotopic Analysis At Separation Creek Area (Van Soest, Et Al...

    Open Energy Info (EERE)

    Usefulness useful DOE-funding Unknown References M. C. van Soest, B. M. Kennedy, W. C. Evans, R. H. Mariner (2002) Mantle Helium And Carbon Isotopes In Separation Creek...

  20. Electron Bubbles in Liquid Helium

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

    Electron Bubbles in Liquid Helium and Quantum Mechanics Humphrey J. Maris Brown University September 16, 2015 4:00 p.m. An electron entering liquid helium forces open a cavity referred to as an electron bubble. These objects have been studied in many past experiments and appear to be well understood. However, experiments have revealed that in addition to these normal electron bubbles there are other negatively charged objects in liquid helium. Despite much effort the structure of these so-called

  1. Exploring the isopycnal mixing and helium-heat paradoxes in a suite of Earth System Models

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

    Gnanadesikan, A.; Abernathey, R.; Pradal, M.-A.

    2014-11-20

    This paper uses a suite of Earth System models which simulate the distribution of He isotopes and radiocarbon to examine two paradoxes in Earth science. The helium-heat paradox refers to the fact that helium emissions to the deep ocean are far lower than would be expected given the rate of geothermal heating, since both are thought to be the result of radioactive decay in the earth's interior. The isopycnal mixing paradox comes from the fact that many theoretical parameterizations of the isopycnal mixing coefficient ARedi that link it to baroclinic instability project it to be small (of order a fewmore » hundred m2 s−1) in the ocean interior away from boundary currents. However, direct observations using tracers and floats (largely in the upper ocean) suggest that values of this coefficient are an order of magnitude higher. Because helium isotopes equilibrate rapidly with the atmosphere, but radiocarbon equilibrates slowly, it might be thought that resolving the isopycnal mixing paradox in favor of the higher observational estimates of ARedi might also solve the helium paradox. In this paper we show that this is not the case. In a suite of models with different spatially constant and spatially varying values of ARedi the distribution of radiocarbon and helium isotopes is sensitive to the value of ARedi. However, away from strong helium sources in the Southeast Pacific, the relationship between the two is not sensitive, indicating that large-scale advection is the limiting process for removing helium and radiocarbon from the deep ocean. The helium isotopes, in turn, suggest a higher value of ARedi in the deep ocean than is seen in theoretical parameterizations based on baroclinic growth rates. We argue that a key part of resolving the isopycnal mixing paradox is to abandon the idea that ARedi has a direct relationship to local baroclinic instability and to the so called "thickness" mixing coefficient AGM.« less

  2. DEUTERIUM, TRITIUM, AND HELIUM DESORPTION FROM AGED TITANIUM TRITIDES. PART I.

    SciTech Connect (OSTI)

    Shanahan, K; Jeffrey Holder, J

    2006-07-10

    Six new samples of tritium-aged bulk titanium have been examined by thermal desorption and isotope exchange chemistry. The discovery of a lower temperature hydrogen desorption state in these materials, previously reported, has been confirmed in one of the new samples. The helium release of the samples shows the more severe effects obtained from longer aging periods, i.e. higher initial He/M ratios. Several of the more aged samples were spontaneously releasing helium. Part I will discuss the new results on the new lower temperature hydrogen desorption state found in one more extensively studied sample. Part II will discuss the hydrogen/helium release behavior of the remaining samples.

  3. DEUTERIUM, TRITIUM, AND HELIUM DESORPTION FROM AGED TITANIUM TRITIDES. PART II.

    SciTech Connect (OSTI)

    Shanahan, K; Jeffrey Holder, J

    2006-08-17

    Six new samples of tritium-aged bulk titanium have been examined by thermal desorption and isotope exchange chemistry. The discovery of a lower temperature hydrogen desorption state in these materials, previously reported, has been confirmed in one of the new samples. The helium release of the samples shows the more severe effects obtained from longer aging periods, i.e. higher initial He/M ratios. Several of the more aged samples were spontaneously releasing helium. Part I discussed the new results on the new lower temperature hydrogen desorption state found in one more extensively studied sample. Part II will discuss the hydrogen/helium release behavior of the remaining samples.

  4. Helium dilution refrigeration system

    DOE Patents [OSTI]

    Roach, P.R.; Gray, K.E.

    1988-09-13

    A helium dilution refrigeration system operable over a limited time period, and recyclable for a next period of operation is disclosed. The refrigeration system is compact with a self-contained pumping system and heaters for operation of the system. A mixing chamber contains [sup 3]He and [sup 4]He liquids which are precooled by a coupled container containing [sup 3]He liquid, enabling the phase separation of a [sup 3]He rich liquid phase from a dilute [sup 3]He-[sup 4]He liquid phase which leads to the final stage of a dilution cooling process for obtaining low temperatures. The mixing chamber and a still are coupled by a fluid line and are maintained at substantially the same level with the still cross sectional area being smaller than that of the mixing chamber. This configuration provides maximum cooling power and efficiency by the cooling period ending when the [sup 3]He liquid is depleted from the mixing chamber with the mixing chamber nearly empty of liquid helium, thus avoiding unnecessary and inefficient cooling of a large amount of the dilute [sup 3]He-[sup 4]He liquid phase. 2 figs.

  5. Helium dilution refrigeration system

    DOE Patents [OSTI]

    Roach, Patrick R.; Gray, Kenneth E.

    1988-01-01

    A helium dilution refrigeration system operable over a limited time period, and recyclable for a next period of operation. The refrigeration system is compact with a self-contained pumping system and heaters for operation of the system. A mixing chamber contains .sup.3 He and .sup.4 He liquids which are precooled by a coupled container containing .sup.3 He liquid, enabling the phase separation of a .sup.3 He rich liquid phase from a dilute .sup.3 He-.sup.4 He liquid phase which leads to the final stage of a dilution cooling process for obtaining low temperatures. The mixing chamber and a still are coupled by a fluid line and are maintained at substantially the same level with the still cross sectional area being smaller than that of the mixing chamber. This configuration provides maximum cooling power and efficiency by the cooling period ending when the .sup.3 He liquid is depleted from the mixing chamber with the mixing chamber nearly empty of liquid helium, thus avoiding unnecessary and inefficient cooling of a large amount of the dilute .sup.3 He-.sup.4 He liquid phase.

  6. Isotope Science

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

    Science and Production 35 years of experience in isotope production, processing, and applications. Llllll Committed to the safe and reliable production of radioisotopes, products, and services. Contact: Kevin John LANL Isotope Program Manager kjohn@lanl.gov 505-667-3602 Sponsored by the Department of Energy National Isotope Program http://www.nuclear.energy.gov/isotopes/nelsotopes2a.html Isotopes for Environmental Science Isotopes produced at Los Alamos National Laboratory are used as

  7. Isotopes Products

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

    Other isotopes that have recently shipped from LANL's isotope program include cadmium-109 (X-ray fluorescence sources), arsenic-72 (medical research), and sodium-22 (PET sources).

  8. ITER helium ash accumulation

    SciTech Connect (OSTI)

    Hogan, J.T.; Hillis, D.L.; Galambos, J.; Uckan, N.A. ); Dippel, K.H.; Finken, K.H. . Inst. fuer Plasmaphysik); Hulse, R.A.; Budny, R.V. . Plasma Physics Lab.)

    1990-01-01

    Many studies have shown the importance of the ratio {upsilon}{sub He}/{upsilon}{sub E} in determining the level of He ash accumulation in future reactor systems. Results of the first tokamak He removal experiments have been analysed, and a first estimate of the ratio {upsilon}{sub He}/{upsilon}{sub E} to be expected for future reactor systems has been made. The experiments were carried out for neutral beam heated plasmas in the TEXTOR tokamak, at KFA/Julich. Helium was injected both as a short puff and continuously, and subsequently extracted with the Advanced Limiter Test-II pump limiter. The rate at which the He density decays has been determined with absolutely calibrated charge exchange spectroscopy, and compared with theoretical models, using the Multiple Impurity Species Transport (MIST) code. An analysis of energy confinement has been made with PPPL TRANSP code, to distinguish beam from thermal confinement, especially for low density cases. The ALT-II pump limiter system is found to exhaust the He with maximum exhaust efficiency (8 pumps) of {approximately}8%. We find 1<{upsilon}{sub He}/{upsilon}{sub E}<3.3 for the database of cases analysed to date. Analysis with the ITER TETRA systems code shows that these values would be adequate to achieve the required He concentration with the present ITER divertor He extraction system.

  9. Pulsed helium ionization detection system

    DOE Patents [OSTI]

    Ramsey, Roswitha S. (Knoxville, TN); Todd, Richard A. (Knoxville, TN)

    1987-01-01

    A helium ionization detection system is provided which produces stable operation of a conventional helium ionization detector while providing improved sensitivity and linearity. Stability is improved by applying pulsed dc supply voltage across the ionization detector, thereby modifying the sampling of the detectors output current. A unique pulse generator is used to supply pulsed dc to the detector which has variable width and interval adjust features that allows up to 500 V to be applied in pulse widths ranging from about 150 nsec to about dc conditions.

  10. Pulsed helium ionization detection system

    DOE Patents [OSTI]

    Ramsey, R.S.; Todd, R.A.

    1985-04-09

    A helium ionization detection system is provided which produces stable operation of a conventional helium ionization detector while providing improved sensitivity and linearity. Stability is improved by applying pulsed dc supply voltage across the ionization detector, thereby modifying the sampling of the detectors output current. A unique pulse generator is used to supply pulsed dc to the detector which has variable width and interval adjust features that allows up to 500 V to be applied in pulse widths ranging from about 150 nsec to about dc conditions.

  11. Mantle Helium And Carbon Isotopes In Separation Creek Geothermal...

    Open Energy Info (EERE)

    cold springs in the Separation Creek area near South Sister volcano carry a strong mantle signal, indicating the presence of fresh basaltic magma in the volcanic plumbing system....

  12. Regional And Local Trends In Helium Isotopes, Basin And Range...

    Open Energy Info (EERE)

    zones of deep mantle melting or deep permeable pathways (faults) with high vertical fluid flow rates. A detailed study of one of the He-spikes (Dixie Valley and the...

  13. Helium Isotopes in Geothermal and Volcanic Gases of the Western...

    Open Energy Info (EERE)

    are also occurring, although near-surface, pH-related CO2HCO3 equilibria obscure the nature of this effect.Substantial changes in View the MathML source ratios were observed in...

  14. Isotope separation

    DOE Patents [OSTI]

    Bartlett, Rodney J.; Morrey, John R.

    1978-01-01

    A method and apparatus is described for separating gas molecules containing one isotope of an element from gas molecules containing other isotopes of the same element in which all of the molecules of the gas are at the same electronic state in their ground state. Gas molecules in a gas stream containing one of the isotopes are selectively excited to a different electronic state while leaving the other gas molecules in their original ground state. Gas molecules containing one of the isotopes are then deflected from the other gas molecules in the stream and thus physically separated.

  15. Energy, helium, and the future: II

    SciTech Connect (OSTI)

    Krupka, M.C.; Hammel, E.F.

    1980-01-01

    The importance of helium as a critical resource material has been recognized specifically by the scientific community and more generally by the 1960 Congressional mandate to institute a long-range conservation program. A major study mandated by the Energy Reorganization Act of 1974 resulted in the publication in 1975 of the document, The Energy-Related Applications of Helium, ERDA-13. This document contained a comprehensive review and analysis relating to helium resources and present and future supply/demand relationships with particular emphasis upon those helium-dependent energy-related technologies projected to be implemented in the post-2000 year time period, e.g., fusion. An updated overview of the helium situation as it exists today is presented. Since publication of ERDA-13, important changes in the data base underlying that document have occurred. The data have since been reexamined, revised, and new information included. Potential supplies of helium from both conventional and unconventional natural gas resources, projected supply/demand relationships to the year 2030 based upon a given power-generation scenario, projected helium demand for specific energy-related technologies, and the supply options (national and international) available to meet that demand are discussed. An updated review will be given of the energy requirements for the extraction of helium from natural gas as they relate to the concentration of helium. A discussion is given concerning the technical and economic feasibility of several methods available both now and conceptually possible, to extract helium from helium-lean natural gas, the atmosphere, and outer space. Finally, a brief review is given of the 1980 Congressional activities with respect to the introduction and possible passage of new helium conservation legislation.

  16. Supply and Demand of Helium-3| U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

    Supply and Demand of Helium-3 Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Funding Opportunities Nuclear Science Advisory Committee (NSAC) Community Resources Contact Information Nuclear Physics U.S. Department of Energy SC-26/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3613 F: (301) 903-3833 E: Email Us More Information » Isotope Development & Production for Research and Applications (IDPRA) Supply and Demand

  17. Relativistic calculations of isotope shifts in highly charged ions

    SciTech Connect (OSTI)

    Tupitsyn, I.I.; Shabaev, V.M.; Crespo Lopez-Urrutia, J.R.; Soria Orts, R.; Ullrich, J.; Draganic, I.

    2003-08-01

    The isotope shifts of forbidden transitions in Be- and B-like argon ions are calculated. It is shown that only using the relativistic recoil operator can provide a proper evaluation of the mass isotope shift, which strongly dominates over the field isotope shift for the ions under consideration. Comparing the isotope shifts calculated with the current experimental uncertainties indicates very good perspectives for a first test of the relativistic theory of the recoil effect in middle-Z ions.

  18. Isotope geochemistry

    SciTech Connect (OSTI)

    Cole, D.R.; Curtis, D.B.; DePaolo, D.J.; Gerlach, T.M.; Laul, J.C.; Shaw, H.; Smith, B.M.; Sturchio, N.C.

    1990-09-01

    This document represents the consensus of members of the ad hoc Committee on Isotope Geochemistry in the US Department of Energy; the committee is composed of researchers in isotope geochemistry from seven of the national laboratories. Information included in this document was presented at workshops at Lawrence Berkeley Laboratory (April 1989) and at Los Alamos National Laboratory (August 1989).

  19. LANL researchers simulate helium bubble behavior in fusion reactors

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

    Researchers simulate helium bubble behavior LANL researchers simulate helium bubble behavior in fusion reactors A team performed simulations to understand more fully how tungsten behaves in such harsh conditions, particularly in the presence of implanted helium that forms bubbles in the material. August 4, 2015 Simulation snapshots of the helium bubble just before bursting. Colors indicate tungsten atoms (red) and helium atoms (blue). Simulation snapshots of the helium bubble just before

  20. Double, Double Toil and Trouble: Tungsten Burns and Helium Bubbles...

    Office of Science (SC) Website

    Helium bubbles are detrimental to plasma-facing materials such as tungsten in fusion reactors, which could serve as a possible new power source. Thus, understanding how helium ...

  1. Surprisingly Large Generation and Retention of Helium and Hydrogen...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Surprisingly Large Generation and Retention of Helium and Hydrogen in ... Title: Surprisingly Large Generation and Retention of Helium and Hydrogen in Pure Nickel ...

  2. Helium Migration Mechanisms in Polycrystalline Uranium Dioxide

    SciTech Connect (OSTI)

    Martin, Guillaume; Desgardin, Pierre; Sauvage, Thierry; Barthe, Marie-France; Garcia, Philippe; Carlot, Gaelle

    2007-07-01

    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)

  3. Isotopes Products

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

    Isotopes Products Isotopes Products Isotopes produced at Los Alamos National Laboratory are saving lives, advancing cutting-edge research and keeping the U.S. safe. Products stress and rest Stress and rest Rb-82 PET images in a patient with dipyridamole stress-inducible lateral wall and apical ischemia. (http://www.fac.org.ar/scvc/llave/image/machac/machaci.htm#f2,3,4) Strontium-82 is supplied to our customers for use in Sr-82/Rb-82 generator technologies. The generators in turn are supplied to

  4. Helium measurements of pore-fluids obtained from SAFOD drillcore

    SciTech Connect (OSTI)

    Ali, S.; Stute, M.; Torgersen, T.; Winckler, G.; Kennedy, B.M.

    2010-04-15

    {sup 4}He accumulated in fluids is a well established geochemical tracer used to study crustal fluid dynamics. Direct fluid samples are not always collectable; therefore, a method to extract rare gases from matrix fluids of whole rocks by diffusion has been adapted. Helium was measured on matrix fluids extracted from sandstones and mudstones recovered during the San Andreas Fault Observatory at Depth (SAFOD) drilling in California, USA. Samples were typically collected as subcores or from drillcore fragments. Helium concentration and isotope ratios were measured 4-6 times on each sample, and indicate a bulk {sup 4}He diffusion coefficient of 3.5 {+-} 1.3 x 10{sup -8} cm{sup 2}s{sup -1} at 21 C, compared to previously published diffusion coefficients of 1.2 x 10{sup -18} cm{sup 2}s{sup -1} (21 C) to 3.0 x 10{sup -15} cm{sup 2}s{sup -1} (150 C) in the sands and clays. Correcting the diffusion coefficient of {sup 4}He{sub water} for matrix porosity ({approx}3%) and tortuosity ({approx}6-13) produces effective diffusion coefficients of 1 x 10{sup -8} cm{sup 2}s{sup -1} (21 C) and 1 x 10{sup -7} (120 C), effectively isolating pore fluid {sup 4}He from the {sup 4}He contained in the rock matrix. Model calculations indicate that <6% of helium initially dissolved in pore fluids was lost during the sampling process. Complete and quantitative extraction of the pore fluids provide minimum in situ porosity values for sandstones 2.8 {+-} 0.4% (SD, n=4) and mudstones 3.1 {+-} 0.8% (SD, n=4).

  5. Helium refrigeration considerations for cryomodule design

    SciTech Connect (OSTI)

    Ganni, V.; Knudsen, P.

    2014-01-29

    Many of the present day accelerators are based on superconducting radio frequency (SRF) cavities, packaged in cryo-modules (CM), which depend on helium refrigeration at sub-atmospheric pressures, nominally 2 K. These specialized helium refrigeration systems are quite cost intensive to produce and operate. Particularly as there is typically no work extraction below the 4.5-K supply, it is important that the exergy loss between this temperature level and the CM load temperature(s) be minimized by the process configuration choices. This paper will present, compare and discuss several possible helium distribution process arrangements to support the CM loads.

  6. A comparison of hydrogen vs. helium glow discharge effects on fusion device first-wall conditioning

    SciTech Connect (OSTI)

    Dylla, H.F.

    1989-09-01

    Hydrogen- and deuterium-fueled glow discharges are used for the initial conditioning of magnetic fusion device vacuum vessels following evacuation from atmospheric pressure. Hydrogenic glow discharge conditioning (GDC) significantly reduces the near-surface concentration of simple adsorbates, such as H/sub 2/O, CO, and CH/sub 4/, and lowers ion-induced desorption coefficients by typically three orders of magnitude. The time evolution of the residual gas production observed during hydrogen-glow discharge conditioning of the carbon first-wall structure of the TFTR device is similar to the time evolution observed during hydrogen GDC of the initial first-wall configuration in TFTR, which was primarily stainless steel. Recently, helium GDC has been investigated for several wall-conditioning tasks on a number of tokamaks including TFTR. Helium GDC shows negligible impurity removal with stainless steel walls. For impurity conditioning with carbon walls, helium GDC shows significant desorption of H/sub 2/O, CO, and CO/sub 2/; however, the total desorption yield is limited to the monolayer range. In addition, helium GDC can be used to displace hydrogen isotopes from the near-surface region of carbon first-walls in order to lower hydrogenic retention and recycling. 38 refs., 6 figs.

  7. ISOTOPE SEPARATORS

    DOE Patents [OSTI]

    Bacon, C.G.

    1958-08-26

    An improvement is presented in the structure of an isotope separation apparatus and, in particular, is concerned with a magnetically operated shutter associated with a window which is provided for the purpose of enabling the operator to view the processes going on within the interior of the apparatus. The shutier is mounted to close under the force of gravity in the absence of any other force. By closing an electrical circuit to a coil mouated on the shutter the magnetic field of the isotope separating apparatus coacts with the magnetic field of the coil to force the shutter to the open position.

  8. I ISOTOPES

    Office of Legacy Management (LM)

    fl6-6 ' , WTELEEYNE I ISOTOPES i - ' 50<77 /,' y. 6 IWL-5025-473 SUBSURFACE URASIUM OJ: THE GROUNDS OF NL BEARINGS, ALBAh'Y Heyitt Iv. Jeter Douglas M. Eagleson Fred J. Frullo TELEDYNE ISOTOPES 50 VAK BUREN A\!EMJE WESTKOOD, NEK JERSEY 07675 7 Dcccmhcr 1953 Prepnrcd for NL f%carings/NL Tndustrics, Inc. 1130 CCVltrill AXr~lMIC Allmy, New York 12205 TABLE OF CONTEhTS 1.0 INTRODUCTION 2.0 METHODS 2.1 Soil Sampling 2.2 Sample Preparation 2.3 Analysis of Samples 3.0 RESULTS 4.0 SUMMARY REFERENCES

  9. Tritium-helium effects in metals

    SciTech Connect (OSTI)

    Caskey, G.R.

    1985-09-01

    Investigations of helium effects in metals at the Savannah River Laboratory have been carried out by introducing helium by radioactive decay of tritium. This process does not create concurrent radiation damage, such as accompanies ion implantation and (n,..cap alpha..) reactions. The process has its own peculiarities, however, which partially mask and interact with the helium effect of interest. The distribution and local concentration of helium and tritium, which are responsible for changes in mechanical properties and fracture mode, are controlled by the large difference in solubility and diffusivity between the two atoms and by their differing interaction energies with lattice defects, impurities, and internal boundaries. Furthermore, in all investigations with helium generated from tritium decay, some tritium and deuterium are always present. Consequently, property changes include tritium-helium interaction effects to some extent. Results of investigations with several austenitic stainless steels, Armco iron, and niobium single crystals illustrate the variety of phenomena and some of the complex interactions that can be encountered.

  10. Tritium-helium effects in metals

    SciTech Connect (OSTI)

    Caskey, G.R. Jr.

    1985-01-01

    Investigations of helium effects in metals at the Savannah River Laboratory have been carried out by introducing helium by radioactive decay of tritium. This process does not create concurrent radiation damage, such as accompanies ion implantation and (n,..cap alpha..) reactions. The process has its own peculiarities, however, which partially mask and interact with the helium effect of interest. The distribution and local concentration of helium and tritium, which are responsible for changes in mechanical properties and fracture mode, are controlled by the large difference in solubility and diffusivity between the two atoms and by their differing interaction energies with lattice defects, impurities, and internal boundaries. Furthermore, in all investigations with helium generated from tritium decay, some tritium and deuterium are always present. Consequently, property changes include tritium-helium interaction effects to some extent. Results of investigations with several austenitic stainless steels, Armco iron, and niobium single crystals illustrate the variety of phenomena and some of the complex interactions that can be encountered.

  11. Helium (3) Rich Solar Flares

    DOE R&D Accomplishments [OSTI]

    Colgate, S. A.; Audouze, J.; Fowler, W. A.

    1977-05-03

    The extreme enrichment of {sup 3} He {sup 4} He greater than or equal to 1 in some solar flares as due to spallation and the subsequent confinement of the products in a high temperature, kT approx. = 200 keV, high density, n{sub e} approx. = 3 x 10{sup 15} cm {sup -3} plasma associated with the magnetic instability producing the flare is interpreted. The pinch or filament is a current of high energy protons that creates the spallation and maintains the temperature that produces the high energy x-ray spectrum and depletes other isotopes D, Li, Be, and B as observed. Finally the high temperature plasma is a uniquely efficient spallation target that is powered by the interaction of stellar convection and self generated magnetic field.

  12. TRANSPARENT HELIUM IN STRIPPED ENVELOPE SUPERNOVAE

    SciTech Connect (OSTI)

    Piro, Anthony L.; Morozova, Viktoriya S., E-mail: piro@caltech.edu [Theoretical Astrophysics, California Institute of Technology, 1200 E. California Blvd., M/C 350-17, Pasadena, CA 91125 (United States)

    2014-09-01

    Using simple arguments based on photometric light curves and velocity evolution, we propose that some stripped envelope supernovae (SNe) show signs that a significant fraction of their helium is effectively transparent. The main pieces of evidence are the relatively low velocities with little velocity evolution, as are expected deep inside an exploding star, along with temperatures that are too low to ionize helium. This means that the helium should not contribute to the shaping of the main SN light curve, and thus the total helium mass may be difficult to measure from simple light curve modeling. Conversely, such modeling may be more useful for constraining the mass of the carbon/oxygen core of the SN progenitor. Other stripped envelope SNe show higher velocities and larger velocity gradients, which require an additional opacity source (perhaps the mixing of heavier elements or radioactive nickel) to prevent the helium from being transparent. We discuss ways in which similar analysis can provide insights into the differences and similarities between SNe Ib and Ic, which will lead to a better understanding of their respective formation mechanisms.

  13. SCREW COMPRESSOR CHARACTERISTICS FOR HELIUM REFRIGERATION SYSTEMS

    SciTech Connect (OSTI)

    Ganni, Venkatarao; Knudsen, Peter; Creel, Jonathan; Arenius, Dana; Casagrande, Fabio; Howell, Matt

    2008-03-01

    The oil injected screw compressors have practically replaced all other types of compressors in modern helium refrigeration systems due to their large displacement capacity, minimal vibration, reliability and capability of handling helium's high heat of compression.At the present state of compressor system designs for helium systems, typically two-thirds of the lost input power is due to the compression system. Therefore it is important to understand the isothermal and volumetric efficiencies of these machines to help properly design these compression systems to match the refrigeration process. This presentation summarizes separate tests that have been conducted on Sullair compressors at the Superconducting Super-Collider Laboratory (SSCL) in 1993, Howden compressors at Jefferson Lab (JLab) in 2006 and Howden compressors at the Spallation Neutron Source (SNS) in 2006. This work is part of an ongoing study at JLab to understand the theoretical basis for these efficiencies and their loss

  14. Hydrogen isotope MicroChemLab FY15.

    SciTech Connect (OSTI)

    Robinson, David; Luo, Weifang; Stewart, Kenneth D.

    2015-09-01

    We have developed a new method to measure the composition of gaseous mixtures of any two hydrogen isotopes, as well as an inert gas component. When tritium is one of those hydrogen isotopes, there is usually some helium present, because the tritium decays to form helium at a rate of about 1% every 2 months. The usual way of measuring composition of these mixtures involves mass spectrometry, which involves bulky, energy-intensive, expensive instruments, including vacuum pumps that can quite undesirably disperse tritium. Our approach uses calorimetry of a small quantity of hydrogen-absorbing material to determine gas composition without consuming or dispersing the analytes. Our work was a proof of principle using a rather large and slow benchtop calorimeter. Incorporation of microfabricated calorimeters, such as those that have been developed in Sandia’s MicroChemLab program or that are now commercially available, would allow for faster measurements and a smaller instrument footprint.

  15. Helium damage in austenitic stainless steels

    SciTech Connect (OSTI)

    Caskey, G.R. Jr.; Mezzanotte, D.A. Jr.; Rawl, D.E. Jr.

    1983-01-01

    Helium produced by tritium decay was first shown to embrittle austenitic stainless steel at ambient temperature in tensile specimens of Nitronic-40 steel (Armco, Inc.). A long-term study was initiated to study this form of helium damage in five austenitic alloys. Results from this study have been analyzed by the J-integral technique and show a decrease in ductile fracture toughness with increasing He-3 concentration. Sustained-load cracking tests indicate that the stress intensity required to initiate and propagate a crack also decreases with increasing He-3 concentration. 9 figures, 3 tables.

  16. Continuum-scale Modeling of Hydrogen and Helium Bubble Growth...

    Office of Environmental Management (EM)

    Continuum-scale Modeling of Hydrogen and Helium Bubble Growth in Metals Continuum-scale Modeling of Hydrogen and Helium Bubble Growth in Metals Presentation from the 34th Tritium ...

  17. Climate Perspectives

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

    Climate Perspectives Climate Perspectives: Change in the Terrestrial Arctic Rising temperatures are rapidly reshaping the terrestrial Arctic. Climate Perspectives: Change in the Terrestrial Arctic is an interactive look at Arctic climate change and climate science through the eyes of scientists and artists. Climate Perspectives slide 1 Climate Perspectives Climate Perspectives is interactive. This slideshow represents a sample of the content within the exhibit. Climate Perspectives slide 2

  18. Stepped-anneal and total helium/hydrogen measurements in high-energy proton-irradiated tungsten

    SciTech Connect (OSTI)

    Oliver, B.M.; Hamilton, M.L.; Garner, F.A.; Sommer, W.F.; Maloy, S.A.; Ferguson, P.D.

    1998-12-31

    To provide structural material design data for the Accelerator Production of Tritium (APT) project, a 1 mA, 800 MeV proton beam at the Los Alamos Neutron Science Center (LANSCE) was used to irradiate a large number of metal samples, including a tungsten target similar to that being considered as the neutron source for the tritium production. The maximum proton fluence to the tungsten target was {approximately} 10{sup 21} protons/cm{sup 2}. An unavoidable byproduct of spallation reactions is the formation of large amounts of hydrogen and helium. Postulated accident scenarios for APT involving the use of tungsten rods clad with Alloy 718, raise concerns as to the amount and rate of release of these gases due to temperatures increases from afterheat accumulation, with the major concern being pressurizing and possibly failure of the cladding. To address these issues, portions of the LANSCE tungsten rods were subjected to temperature histories calculated as likely to occur, and the time-dependent evolution of helium and hydrogen gases was measured. Stepped-anneal and total helium/hydrogen measurements were conducted on multiple samples of the tungsten material. Helium measurements were conducted at Pacific Northwest National Laboratory (PNNL) using a high-sensitivity magnetic-sector isotope-dilution helium analysis system. Stepped-anneal measurements were conducted at temperatures from {approximately} 25 C to {approximately} 1,600 C in {approximately} 100 C steps. Total helium measurements were conducted by rapid vaporization after completion of the stepped-anneal process, and are compared with Monte Carlo calculations performed at Los Alamos National Laboratory (LANL) using the LAHET code system. Hydrogen measurements were conducted between {approximately} 750 C and {approximately} 1,200 C using a high-temperature furnace that had been extensively modified for the application. Hydrogen detection was accomplished by periodic sampling of the furnace gas using a separate

  19. Method for separating isotopes

    DOE Patents [OSTI]

    Jepson, B.E.

    1975-10-21

    Isotopes are separated by contacting a feed solution containing the isotopes with a cyclic polyether wherein a complex of one isotope is formed with the cyclic polyether, the cyclic polyether complex is extracted from the feed solution, and the isotope is thereafter separated from the cyclic polyether.

  20. Stable isotope studies

    SciTech Connect (OSTI)

    Ishida, T.

    1992-01-01

    The research has been in four general areas: (1) correlation of isotope effects with molecular forces and molecular structures, (2) correlation of zero-point energy and its isotope effects with molecular structure and molecular forces, (3) vapor pressure isotope effects, and (4) fractionation of stable isotopes. 73 refs, 38 figs, 29 tabs.

  1. THERMAL OSCILLATIONS IN LIQUID HELIUM TARGETS.

    SciTech Connect (OSTI)

    WANG,L.; JIA,L.X.

    2001-07-16

    A liquid helium target for the high-energy physics was built and installed in the proton beam line at the Alternate Gradient Synchrotron of Brookhaven National Laboratory in 2001. The target flask has a liquid volume of 8.25 liters and is made of thin Mylar film. A G-M/J-T cryocooler of five-watts at 4.2K was used to produce liquid helium and refrigerate the target. A thermosyphon circuit for the target was connected to the J-T circuit by a liquid/gas separator. Because of the large heat load to the target and its long transfer lines, thermal oscillations were observed during the system tests. To eliminate the oscillation, a series of tests and analyses were carried out. This paper describes the phenomena and provides the understanding of the thermal oscillations in the target system.

  2. Closed-loop pulsed helium ionization detector

    DOE Patents [OSTI]

    Ramsey, Roswitha S.; Todd, Richard A.

    1987-01-01

    A helium ionization detector for gas chromatography is operated in a constant current, pulse-modulated mode by configuring the detector, electrometer and a high voltage pulser in a closed-loop control system. The detector current is maintained at a fixed level by varying the frequency of fixed-width, high-voltage bias pulses applied to the detector. An output signal proportional to the pulse frequency is produced which is indicative of the charge collected for a detected species.

  3. Combined cold compressor/ejector helium refrigerator

    DOE Patents [OSTI]

    Brown, Donald P.

    1985-01-01

    A refrigeration apparatus having an ejector operatively connected with a cold compressor to form a two-stage pumping system. This pumping system is used to lower the pressure, and thereby the temperature of a bath of boiling refrigerant (helium). The apparatus as thus arranged and operated has substantially improved operating efficiency when compared to other processes or arrangements for achieving a similar low pressure.

  4. Combined cold compressor/ejector helium refrigerator

    DOE Patents [OSTI]

    Brown, D.P.

    1984-06-05

    A refrigeration apparatus having an ejector operatively connected with a cold compressor to form a two-stage pumping system. This pumping system is used to lower the pressure, and thereby the temperature of a bath of boiling refrigerant (helium). The apparatus as thus arranged and operated has substantially improved operating efficiency when compared to other processes or arrangements for achieving a similar low pressure.

  5. Isotope separation by photochromatography

    DOE Patents [OSTI]

    Suslick, K.S.

    1975-10-03

    A photochromatographic method for isotope separation is described. An isotopically mixed molecular species is adsorbed on an adsorptive surface, and the adsorbed molecules are irradiated with radiation of a predetermined wavelength which will selectively excite desired isotopic species. Sufficient energy is transferred to the excited molecules to desorb them from the surface and thus separate them from the undesired isotopic species. The method is particularly applicable to the separation of hydrogen isotopes. (BLM)

  6. Isotope separation by photochromatography

    DOE Patents [OSTI]

    Suslick, Kenneth S.

    1977-01-01

    An isotope separation method which comprises physically adsorbing an isotopically mixed molecular species on an adsorptive surface and irradiating the adsorbed molecules with radiation of a predetermined wavelength which will selectively excite a desired isotopic species. Sufficient energy is transferred to the excited molecules to desorb them from the surface and thereby separate them from the unexcited undesired isotopic species. The method is particularly applicable to the separation of hydrogen isotopes.

  7. In situ controlled modification of the helium density in single helium-filled nanobubbles

    SciTech Connect (OSTI)

    David, M.-L. Pailloux, F.; Alix, K.; Mauchamp, V.; Pizzagalli, L.; Couillard, M.; Botton, G. A.

    2014-03-28

    We demonstrate that the helium density and corresponding pressure can be modified in single nano-scale bubbles embedded in semiconductors by using the electron beam of a scanning transmission electron microscope as a multifunctional probe: the measurement probe for imaging and chemical analysis and the irradiation source to modify concomitantly the pressure in a controllable way by fine tuning of the electron beam parameters. The control of the detrapping rate is achieved by varying the experimental conditions. The underlying physical mechanisms are discussed; our experimental observations suggest that the helium detrapping from bubbles could be interpreted in terms of direct ballistic collisions, leading to the ejection of the helium atoms from the bubble.

  8. Research questions reality of 'supersolid' in helium-4

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

    Research questions reality of 'supersolid' in helium-4 Research questions reality of 'supersolid' in helium-4 When cooled to temperatures below minus 452 degrees below zero Fahrenheit, helium-4 becomes a liquid-and an extraordinary liquid at that. May 17, 2011 Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as a backdrop to research and innovation covering multi-disciplines from bioscience, sustainable energy sources, to plasma

  9. Simplified Helium Refrigerator Cycle Analysis Using the `Carnot Step'

    SciTech Connect (OSTI)

    P. Knudsen; V. Ganni

    2006-05-01

    An analysis of the Claude form of an idealized helium liquefier for the minimum input work reveals the ''Carnot Step'' for helium refrigerator cycles. As the ''Carnot Step'' for a multi-stage polytropic compression process consists of equal pressure ratio stages; similarly for an idealized helium liquefier the ''Carnot Step'' consists of equal temperature ratio stages for a given number of expansion stages. This paper presents the analytical basis and some useful equations for the preliminary examination of existing and new Claude helium refrigeration cycles.

  10. Boron-10 Neutron Detectors for Helium-3 Replacement

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

    efficiencies comparable to Helium-3 detectors, with demonstrated gamma neutron discrimination. Available for thumbnail of Feynman Center (505) 665-9090 Email Boron-10 Neutron...

  11. Alternatives for Helium-3 in Multiplicity Counters

    SciTech Connect (OSTI)

    Ely, James H.; Siciliano, Edward R.; Lintereur, Azaree T.; Swinhoe, Martyn T.

    2013-04-01

    Alternatives to helium-3 are being actively pursued due to the shortage and rising costs of helium-3. For safeguards applications, there are a number of ongoing investigations to find alternatives that provide the same capability in a cost-effective manner. One of the greatest challenges is to find a comparable alternative for multiplicity counters, since they require high efficiency and short collection or die-away times. Work has been progressing on investigating three commercially available alternatives for high efficiency multiplicity counters: boron trifluoride (BF3) filled proportional tubes, boron-lined proportional tubes, and lithium fluoride with zinc sulfide coated light guides. The baseline multiplicity counter used for the investigation is the Epithermal Neutron Multiplicity Counter with 121 helium-3 filled tubes at 10 atmosphere pressure, which is a significant capability to match. The primary tool for the investigation has been modeling and simulation using the Monte Carlo N-Particle eXtended (MCNPX) radiation transport program, with experiments to validate the models. To directly calculate the coincidence rates in boron-lined (and possibly other) detectors, the MCNPX code has been enhanced to allow the existing coincidence tally to be used with energy deposition rather than neutron capture reactions. This allows boron-lined detectors to be modeled more accurately. Variations of tube number and diameter along with variations in the amount of inter-tube moderator have been conducted for the BF3 and boron-lined cases. Tube pressure was investigated for BF3, up to two atmospheres, as well as optimal boron thickness in the boron-lined tubes. The lithium fluoride was modeled as sheets of material with light guides in between, and the number and thickness of the sheets investigated. The amount of light guide, which in this case doubles as a moderator, was also optimized. The results of these modeling and simulation optimization investigations are described

  12. Helium transport and ash control studies

    SciTech Connect (OSTI)

    Miley, G.H.

    1992-01-01

    The Primary goal of this research is to develop a helium (ash) transport scaling law based on experimental data from devices such as TFTR and JET. To illustrate the importance of this, we have studied ash accumulation effects on ignition requirements using a O-D transport model. Ash accumulation is characterized in the model by the ratio of the helium particle confinement time to the energy confinement time t{sub {alpha}}/t{sub E}. Results show that the ignition window'' shrinks rapidly as t{sub {alpha}}/t{sub E} increases, closing for high t{sub {alpha}}/t{sub E} increases, closing for high t{sub {alpha}}/t{sub E}. A best'' value for t{sub {alpha}}/t{sub E} will ultimately be determined from our scaling law studies. A helium transport scaling law is being sought that expresses the transport coefficients (D{sub {alpha}}, V{sub {alpha}}) as a function of the local plasma parameters. This is necessary for use in transport code calculations, e.g. for BALDUR. Based on experimental data from L-mode plasma operation in TFTR, a scaling law to a power law expression has been obtained using a least-square fit method. It is found that the transport coefficients are strongly affected by the local magnetic field and safety factor q. A preliminary conclusion from this work is that active control of ash buildup must be developed. To study control, we have developed a O-D plasma model which employs a simple pole-placement control model. Some preliminary calculations with this model are presented.

  13. Helium-3 and Helium-4 acceleration by high power laser pulses for hadron therapy

    SciTech Connect (OSTI)

    Bulanov, S. S.; Esarey, E.; Schroeder, C. B.; Leemans, W. P.; Bulanov, S. V.; Margarone, D.; Korn, G.; Haberer, T.

    2015-06-24

    The laser driven acceleration of ions is considered a promising candidate for an ion source for hadron therapy of oncological diseases. Though proton and carbon ion sources are conventionally used for therapy, other light ions can also be utilized. Whereas carbon ions require 400 MeV per nucleon to reach the same penetration depth as 250 MeV protons, helium ions require only 250 MeV per nucleon, which is the lowest energy per nucleon among the light ions. This fact along with the larger biological damage to cancer cells achieved by helium ions, than that by protons, makes this species an interesting candidate for the laser driven ion source. Two mechanisms (Magnetic Vortex Acceleration and hole-boring Radiation Pressure Acceleration) of PW-class laser driven ion acceleration from liquid and gaseous helium targets are studied with the goal of producing 250 MeV per nucleon helium ion beams that meet the hadron therapy requirements. We show that He3 ions, having almost the same penetration depth as He4 with the same energy per nucleon, require less laser power to be accelerated to the required energy for the hadron therapy.

  14. Production of thorium-229 using helium nuclei

    DOE Patents [OSTI]

    Mirzadeh, Saed (Knoxville, TN) [Knoxville, TN; Garland, Marc Alan (Knoxville, TN) [Knoxville, TN

    2010-12-14

    A method for producing .sup.229Th includes the steps of providing .sup.226Ra as a target material, and bombarding the target material with alpha particles, helium-3, or neutrons to form .sup.229Th. When neutrons are used, the neutrons preferably include an epithermal neutron flux of at least 1.times.10.sup.13 n s.sup.-1cm.sup.-2. .sup.228Ra can also be bombarded with thermal and/or energetic neutrons to result in a neutron capture reaction to form .sup.229Th. Using .sup.230Th as a target material, .sup.229Th can be formed using neutron, gamma ray, proton or deuteron bombardment.

  15. Manus Water Isotope Investigation

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

    9 Manus Water Isotope Investigation Field Campaign Report JL Conroy D Noone KM Cobb March ... DOESC-ARM-15-079 Manus Water Isotope Investigation Field Campaign Report JL Conroy, ...

  16. Manus Water Isotope Investigation

    Office of Scientific and Technical Information (OSTI)

    ENERGY Office of Science DOESC-ARM-15-079 Manus Water Isotope Investigation Field ... DOESC-ARM-15-079 Manus Water Isotope Investigation Field Campaign Report JL Conroy, ...

  17. Liquid uranium alloy-helium fission reactor

    DOE Patents [OSTI]

    Minkov, V.

    1984-06-13

    This invention describes a nuclear fission reactor which has a core vessel and at least one tandem heat exchanger vessel coupled therewith across upper and lower passages to define a closed flow loop. Nuclear fuel such as a uranium alloy in its liquid phase fills these vessels and flow passages. Solid control elements in the reactor core vessel are adapted to be adjusted relative to one another to control fission reaction of the liquid fuel therein. Moderator elements in the other vessel and flow passages preclude fission reaction therein. An inert gas such as helium is bubbled upwardly through the heat exchanger vessel operable to move the liquid fuel upwardly therein and unidirectionally around the closed loop and downwardly through the core vessel. This helium gas is further directed to heat conversion means outside of the reactor vessels to utilize the heat from the fission reaction to generate useful output. The nuclear fuel operates in the 1200 to 1800/sup 0/C range, and even higher to 2500/sup 0/C.

  18. Liquid uranium alloy-helium fission reactor

    DOE Patents [OSTI]

    Minkov, Vladimir (Skokie, IL)

    1986-01-01

    This invention teaches a nuclear fission reactor having a core vessel and at least one tandem heat exchanger vessel coupled therewith across upper and lower passages to define a closed flow loop. Nuclear fuel such as a uranium alloy in its liquid phase fills these vessels and flow passages. Solid control elements in the reactor core vessel are adapted to be adjusted relative to one another to control fission reaction of the liquid fuel therein. Moderator elements in the other vessel and flow passages preclude fission reaction therein. An inert gas such as helium is bubbled upwardly through the heat exchanger vessel operable to move the liquid fuel upwardly therein and unidirectionally around the closed loop and downwardly through the core vessel. This helium gas is further directed to heat conversion means outside of the reactor vessels to utilize the heat from the fission reaction to generate useful output. The nuclear fuel operates in the 1200.degree.-1800.degree. C. range, and even higher to 2500.degree. C., limited only by the thermal effectiveness of the structural materials, increasing the efficiency of power generation from the normal 30-35% with 300.degree.-500.degree. C. upper limit temperature to 50-65%. Irradiation of the circulating liquid fuel, as contrasted to only localized irradiation of a solid fuel, provides improved fuel utilization.

  19. The primordial helium abundance from updated emissivities

    SciTech Connect (OSTI)

    Aver, Erik; Olive, Keith A.; Skillman, Evan D.; Porter, R.L. E-mail: olive@umn.edu E-mail: skillman@astro.umn.edu

    2013-11-01

    Observations of metal-poor extragalactic H II regions allow the determination of the primordial helium abundance, Y{sub p}. The He I emissivities are the foundation of the model of the H II region's emission. Porter, Ferland, Storey, and Detisch (2012) have recently published updated He I emissivities based on improved photoionization cross-sections. We incorporate these new atomic data and update our recent Markov Chain Monte Carlo analysis of the dataset published by Izotov, Thuan, and Stasi'nska (2007). As before, cuts are made to promote quality and reliability, and only solutions which fit the data within 95% confidence level are used to determine the primordial He abundance. The previously qualifying dataset is almost entirely retained and with strong concordance between the physical parameters. Overall, an upward bias from the new emissivities leads to a decrease in Y{sub p}. In addition, we find a general trend to larger uncertainties in individual objects (due to changes in the emissivities) and an increased variance (due to additional objects included). From a regression to zero metallicity, we determine Y{sub p} = 0.2465 ± 0.0097, in good agreement with the BBN result, Y{sub p} = 0.2485 ± 0.0002, based on the Planck determination of the baryon density. In the future, a better understanding of why a large fraction of spectra are not well fit by the model will be crucial to achieving an increase in the precision of the primordial helium abundance determination.

  20. Double photoionization of helium with synchrotron x-rays: Proceedings

    SciTech Connect (OSTI)

    Not Available

    1994-01-01

    This report contains papers on the following topics: Overview and comparison of photoionization with charged particle impact; The ratio of double to single ionization of helium: the relationship of photon and bare charged particle impact ionization; Double photoionization of helium at high energies; Compton scattering of photons from electrons bound in light elements; Electron ionization and the Compton effect in double ionization of helium; Elimination of two atomic electrons by a single energy photon; Double photoionization of helium at intermediate energies; Double Photoionization: Gauge Dependence, Coulomb Explosion; Single and Double Ionization by high energy photon impact; The effect of Compton Scattering on the double to single ionization ratio in helium; and Double ionization of He by photoionization and Compton scattering. These papers have been cataloged separately for the database.

  1. Detailed and simplified nonequilibrium helium ionization in the solar atmosphere

    SciTech Connect (OSTI)

    Golding, Thomas Peter; Carlsson, Mats; Leenaarts, Jorrit E-mail: mats.carlsson@astro.uio.no

    2014-03-20

    Helium ionization plays an important role in the energy balance of the upper chromosphere and transition region. Helium spectral lines are also often used as diagnostics of these regions. We carry out one-dimensional radiation-hydrodynamics simulations of the solar atmosphere and find that the helium ionization is set mostly by photoionization and direct collisional ionization, counteracted by radiative recombination cascades. By introducing an additional recombination rate mimicking the recombination cascades, we construct a simplified three-level helium model atom consisting of only the ground states. This model atom is suitable for modeling nonequilibrium helium ionization in three-dimensional numerical models. We perform a brief investigation of the formation of the He I 10830 and He II 304 spectral lines. Both lines show nonequilibrium features that are not recovered with statistical equilibrium models, and caution should therefore be exercised when such models are used as a basis for interpretating observations.

  2. Generation of Radixenon Isotopes

    SciTech Connect (OSTI)

    McIntyre, Justin I.; Bowyer, Ted W.; Hayes, James C.; Heimbigner, Tom R.; Morris, Scott J.; Panisko, Mark E.; Pitts, W. K.; Pratt, Sharon L.; Reeder, Paul L.; Thomas, Charles W.

    2003-06-30

    Pacific Northwest National Laboratory has developed an automated system for separating Xe from air and can detect the following radioxenon isotopes, 131mXe, 133mXe, 133Xe, and 135Xe. This report details the techniques used to generate the various radioxenon isotopes that are used for the calibration of the detector as well as other isotopes that have the potential to interfere with the fission produced radioxenon isotopes. Fission production is covered first using highly enriched uranium followed by a description and results from an experiment to produce radioxenon isotopes from neutron activation of ambient xenon.

  3. ISOTOPE CONVERSION DEVICE

    DOE Patents [OSTI]

    Wigner, E.P.; Young, G.J.; Ohlinger, L.A.

    1957-12-01

    This patent relates to nuclear reactors of tbe type utilizing a liquid fuel and designed to convert a non-thermally fissionable isotope to a thermally fissionable isotope by neutron absorption. A tank containing a reactive composition of a thermally fissionable isotope dispersed in a liquid moderator is disposed within an outer tank containing a slurry of a non-thermally fissionable isotope convertible to a thermally fissionable isotope by neutron absorption. A control rod is used to control the chain reaction in the reactive composition and means are provided for circulating and cooling the reactive composition and slurry in separate circuits.

  4. Large-scale atomistic simulations of helium-3 bubble growth in complex palladium alloys

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

    Hale, Lucas M.; Zimmerman, Jonathan A.; Wong, Bryan M.

    2016-05-18

    Palladium is an attractive material for hydrogen and hydrogen-isotope storage applications due to its properties of large storage density and high diffusion of lattice hydrogen. When considering tritium storage, the material’s structural and mechanical integrity is threatened by both the embrittlement effect of hydrogen and the creation and evolution of additional crystal defects (e.g., dislocations, stacking faults) caused by the formation and growth of helium-3 bubbles. Using recently developed inter-atomic potentials for the palladium-silver-hydrogen system, we perform large-scale atomistic simulations to examine the defect-mediated mechanisms that govern helium bubble growth. Our simulations show the evolution of a distribution of materialmore » defects, and we compare the material behavior displayed with expectations from experiment and theory. In conclusion, we also present density functional theory calculations to characterize ideal tensile and shear strengths for these materials, which enable the understanding of how and why our developed potentials either meet or confound these expectations.« less

  5. Superconducting cable cooling system by helium gas and a mixture of gas and liquid helium

    DOE Patents [OSTI]

    Dean, John W.

    1977-01-01

    Thermally contacting, oppositely streaming cryogenic fluid streams in the same enclosure in a closed cycle that changes from a cool high pressure helium gas to a cooler reduced pressure helium fluid comprised of a mixture of gas and boiling liquid so as to be near the same temperature but at different pressures respectively in go and return legs that are in thermal contact with each other and in thermal contact with a longitudinally extending superconducting transmission line enclosed in the same cable enclosure that insulates the line from the ambient at a temperature T.sub.1. By first circulating the fluid in a go leg from a refrigerator at one end of the line as a high pressure helium gas near the normal boiling temperature of helium; then circulating the gas through an expander at the other end of the line where the gas becomes a mixture of reduced pressure gas and boiling liquid at its boiling temperature; then by circulating the mixture in a return leg that is separated from but in thermal contact with the gas in the go leg and in the same enclosure therewith; and finally returning the resulting low pressure gas to the refrigerator for compression into a high pressure gas at T.sub.2 is a closed cycle, where T.sub.1 >T.sub.2, the temperature distribution is such that the line temperature is nearly constant along its length from the refrigerator to the expander due to the boiling of the liquid in the mixture. A heat exchanger between the go and return lines removes the gas from the liquid in the return leg while cooling the go leg.

  6. HYDROGEN ISOTOPE TARGETS

    DOE Patents [OSTI]

    Ashley, R.W.

    1958-08-12

    The design of targets for use in the investigation of nuclear reactions of hydrogen isotopes by bombardment with accelerated particles is described. The target con struction eomprises a backing disc of a metal selected from the group consisting of molybdenunn and tungsten, a eoating of condensed titaniunn on the dise, and a hydrogen isotope selected from the group consisting of deuterium and tritium absorbed in the coatiag. The proeess for preparing these hydrogen isotope targets is described.

  7. Uranium Isotopic Assay Instrument

    SciTech Connect (OSTI)

    Anheier, Norman C.; Wojcik, Michael D.; Bushaw, Bruce A.

    2006-12-01

    The isotopic assay instrument under development at Pacific Northwest National Laboratory (PNNL) is capable of rapid prescreening to detect small and rare particles containing high concentrations of uranium in a heterogeneous sample. The isotopic measurement concept is based on laser vaporization of solid samples followed with sensitive isotope specific detection using either uranium atomic fluorescence emission or uranium atomic absorbance. Both isotopes are measured concurrently, following a single ablation laser pulse, using two external-cavity violet diode lasers. The simultaneous measurement of both isotopes enables the correlation of the fluorescence and absorbance signals on a shot-to-shot basis. This measurement approach demonstrated negligible channel crosstalk between isotopes. Rapid sample scanning provides high spatial resolution isotopic fluorescence and absorbance sample imagery of heterogeneous samples. Laser ablation combined with measurements of laser-induced fluorescence (LALIF) and through-plume laser absorbance (LAPLA) was applied to measure gadolinium isotope ratios in solid samples. Gadolinium has excitation wavelengths very close to the transitions of interest in uranium. Gadolinium has seven stable isotopes, and the natural 152Gd:160Gd ratio of 0.009 is in the range of what will be encountered for 235U:238U isotopic ratios. LAPLA measurements were demonstrated clearly using 152Gd (0.2% isotopic abundance) with a good signal-to-noise ratio. The ability to measure gadolinium abundances at this level indicates that measurements of 235U/238U isotopic ratios for natural (0.72%), depleted (0.25%), and low enriched uranium samples will be feasible.

  8. ARM - Measurement - Isotope ratio

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

    govMeasurementsIsotope ratio ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Isotope ratio Ratio of stable isotope concentrations. Categories Atmospheric State, Atmospheric Carbon Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those

  9. Hybrid isotope separation scheme

    DOE Patents [OSTI]

    Maya, J.

    1991-06-18

    A method is described for yielding selectively a desired enrichment in a specific isotope including the steps of inputting into a spinning chamber a gas from which a scavenger, radiating the gas with a wave length or frequency characteristic of the absorption of a particular isotope of the atomic or molecular gas, thereby inducing a photochemical reaction between the scavenger, and collecting the specific isotope-containing chemical by using a recombination surface or by a scooping apparatus. 2 figures.

  10. Hybrid isotope separation scheme

    DOE Patents [OSTI]

    Maya, Jakob

    1991-01-01

    A method of yielding selectively a desired enrichment in a specific isotope including the steps of inputting into a spinning chamber a gas from which a scavenger, radiating the gas with a wave length or frequency characteristic of the absorption of a particular isotope of the atomic or molecular gas, thereby inducing a photochemical reaction between the scavenger, and collecting the specific isotope-containing chemical by using a recombination surface or by a scooping apparatus.

  11. Stable isotope enrichment

    ScienceCinema (OSTI)

    Egle, Brian

    2014-07-15

    Brian Egle is working to increase the nation's capacity to produce stable isotopes for use including medicine, industry and national security.

  12. Stable isotope enrichment

    SciTech Connect (OSTI)

    Egle, Brian

    2014-07-14

    Brian Egle is working to increase the nation's capacity to produce stable isotopes for use including medicine, industry and national security.

  13. PRINCIPAL ISOTOPE SELECTION REPORT

    SciTech Connect (OSTI)

    K. D. Wright

    1998-08-28

    Utilizing nuclear fuel to produce power in commercial reactors results in the production of hundreds of fission product and transuranic isotopes in the spent nuclear fuel (SNF). When the SNF is disposed of in a repository, the criticality analyses could consider all of the isotopes, some principal isotopes affecting criticality, or none of the isotopes, other than the initial loading. The selected set of principal isotopes will be the ones used in criticality analyses of the SNF to evaluate the reactivity of the fuel/waste package composition and configuration. This technical document discusses the process used to select the principal isotopes and the possible affect that these isotopes could have on criticality in the SNF. The objective of this technical document is to discuss the process used to select the principal isotopes for disposal criticality evaluations with commercial SNF. The principal isotopes will be used as supporting information in the ''Disposal Criticality Analysis Methodology Topical Report'' which will be presented to the United States Nuclear Regulatory Commission (NRC) when approved by the United States Department of Energy (DOE) Office of Civilian Radioactive Waste Management (OCRWM).

  14. How to make Raman-inactive helium visible in Raman spectra of tritium-helium gas mixtures

    SciTech Connect (OSTI)

    Schloesser, M.; Pakari, O.; Rupp, S.; Mirz, S.; Fischer, S.

    2015-03-15

    Raman spectroscopy, a powerful method for the quantitative compositional analysis of molecular gases, e.g. mixtures of hydrogen isotopologues, is not able to detect monoatomic species like helium. This deficit can be overcome by using radioluminescence emission from helium atoms induced by β-electrons from tritium decay. We present theoretical considerations and combined Raman/radioluminescence spectra. Furthermore, we discuss the linearity of the method together with validation measurements for determining the pressure dependence. Finally, we conclude how this technique can be used for samples of helium with traces of tritium, and vice versa. (authors)

  15. Helium bubble distributions in reactor tank repair specimens. Part 1

    SciTech Connect (OSTI)

    Tosten, M.H.; Kestin, P.A.

    1992-03-01

    This report discusses the Reactor Tank Repair (RTR) program was initiated to develop an in-tank repair process capable of repairing stress corrosion cracks within the SRS reactor tank walls, in the event that such a repair is needed. Previous attempts to repair C-reactor tank with a gas tungsten arc (GTA) welding process were unsuccessful due to significant cracking that occurred in the heat-affected-zones adjacent to the repair welds. It was determined that this additional cracking was a result of helium embrittlement caused by the combined effects of helium (existing within the tank walls), the high heat input associated with the GTA process, and weld shrinkage stresses. Based on the results of earlier studies it was suggested that the effects of helium embrittlement could be minimized by using a low heat input GMA process. Metallographic analysis played an important role throughout the investigation of alternative welding methods for the repair of helium-containing materials.

  16. Technique to eliminate helium induced weld cracking in stainless steels

    SciTech Connect (OSTI)

    Chin-An Wang; Chin, B.A.; Grossbeck, M.L.

    1992-12-31

    Experiments have shown that Type 316 stainless steel is susceptible to heat-affected-zone (HAZ) cracking upon cooling when welded using the gas tungsten arc (GTA) process under lateral constraint. The cracking has been hypothesized to be caused by stress-assisted helium bubble growth and rupture at grain boundaries. This study utilized an experimental welding setup which enabled different compressive stresses to be applied to the plates during welding. Autogenous GTA welds were produced in Type 316 stainless steel doped with 256 appm helium. The application of a compressive stress, 55 Mpa, during welding suppressed the previously observed catastrophic cracking. Detailed examinations conducted after welding showed a dramatic change in helium bubble morphology. Grain boundary bubble growth along directions parallel to the weld was suppressed. Results suggest that stress-modified welding techniques may be used to suppress or eliminate helium-induced cracking during joining of irradiated materials.

  17. Helium bubble distributions in reactor tank repair specimens

    SciTech Connect (OSTI)

    Tosten, M.H.; Kestin, P.A.

    1992-03-01

    This report discusses the Reactor Tank Repair (RTR) program was initiated to develop an in-tank repair process capable of repairing stress corrosion cracks within the SRS reactor tank walls, in the event that such a repair is needed. Previous attempts to repair C-reactor tank with a gas tungsten arc (GTA) welding process were unsuccessful due to significant cracking that occurred in the heat-affected-zones adjacent to the repair welds. It was determined that this additional cracking was a result of helium embrittlement caused by the combined effects of helium (existing within the tank walls), the high heat input associated with the GTA process, and weld shrinkage stresses. Based on the results of earlier studies it was suggested that the effects of helium embrittlement could be minimized by using a low heat input GMA process. Metallographic analysis played an important role throughout the investigation of alternative welding methods for the repair of helium-containing materials.

  18. Ab initio study of helium behavior in titanium tritides

    SciTech Connect (OSTI)

    Liang, J. H.; Dai, Yunya; Yang, Li; Peng, SM; Fan, K. M.; Long, XG; Zhou, X. S.; Zu, Xiaotao; Gao, Fei

    2013-03-01

    Ab initio calculations based on density functional theory have been performed to investigate the relative stability of titanium tritides and the helium behavior in stable titanium tritides. The results show that the β-phase TiT1.5 without two tritium along the [100] direction (TiT1.5[100]) is more stable than other possible structures. The stability of titanium tritides decrease with the increased generation of helium in TiT1.5[100]. In addition, helium generated by tritium decay prefers locating at a tetrahedral site, and favorably migrates between two neighbor vacant tetrahedral sites through an intermediate octahedral site in titanium tritides, with a migration energy of 0.23 eV. Furthermore, helium is easily accumulated on a (100) plane in β-phase TiT1.5[100].

  19. Demonstrating Strong Electric Fields in Liquid Helium for Tests...

    Office of Science (SC) Website

    Image courtesy of Los Alamos National Laboratory The Medium Scale High Voltage Test apparatus in TA-53 Building 10 allowed scientists to test electric fields in liquid helium, a ...

  20. Underground helium travels to the Earth's surface via aquifers...

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

    Tweet EmailPrint Before it can put the party in party balloons, helium is carried from deep within the Earth's crust to the surface via aquifers, according to new research...

  1. The Hall D solenoid helium refrigeration system at JLab

    SciTech Connect (OSTI)

    Laverdure, Nathaniel A.; Creel, Jonathan D.; Dixon, Kelly d.; Ganni, Venkatarao; Martin, Floyd D.; Norton, Robert O.; Radovic, Sasa

    2014-01-01

    Hall D, the new Jefferson Lab experimental facility built for the 12GeV upgrade, features a LASS 1.85 m bore solenoid magnet supported by a 4.5 K helium refrigerator system. This system consists of a CTI 2800 4.5 K refrigerator cold box, three 150 hp screw compressors, helium gas management and storage, and liquid helium and nitrogen storage for stand-alone operation. The magnet interfaces with the cryo refrigeration system through an LN2-shielded distribution box and transfer line system, both designed and fabricated by JLab. The distribution box uses a thermo siphon design to respectively cool four magnet coils and shields with liquid helium and nitrogen. We describe the salient design features of the cryo system and discuss our recent commissioning experience.

  2. Price Quotes and Isotope Ordering

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

    Ordering Price Quotes and Isotope Ordering Isotopes produced at Los Alamos National Laboratory are saving lives, advancing cutting-edge research and keeping the U.S. safe. Isotope...

  3. Helium segregation on surfaces of plasma-exposed tungsten

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

    Maroudas, Dimitrios; Blondel, Sophie; Hu, Lin; Hammond, Karl D.; Wirth, Brian D.

    2016-01-21

    Here we report a hierarchical multi-scale modeling study of implanted helium segregation on surfaces of tungsten, considered as a plasma facing component in nuclear fusion reactors. We employ a hierarchy of atomic-scale simulations based on a reliable interatomic interaction potential, including molecular-statics simulations to understand the origin of helium surface segregation, targeted molecular-dynamics (MD) simulations of near-surface cluster reactions, and large-scale MD simulations of implanted helium evolution in plasma-exposed tungsten. We find that small, mobile He-n (1 <= n <= 7) clusters in the near-surface region are attracted to the surface due to an elastic interaction force that provides themore » thermodynamic driving force for surface segregation. Elastic interaction force induces drift fluxes of these mobile Hen clusters, which increase substantially as the migrating clusters approach the surface, facilitating helium segregation on the surface. Moreover, the clusters' drift toward the surface enables cluster reactions, most importantly trap mutation, in the near-surface region at rates much higher than in the bulk material. Moreover, these near-surface cluster dynamics have significant effects on the surface morphology, near-surface defect structures, and the amount of helium retained in the material upon plasma exposure. We integrate the findings of such atomic-scale simulations into a properly parameterized and validated spatially dependent, continuum-scale reaction-diffusion cluster dynamics model, capable of predicting implanted helium evolution, surface segregation, and its near-surface effects in tungsten. This cluster-dynamics model sets the stage for development of fully atomistically informed coarse-grained models for computationally efficient simulation predictions of helium surface segregation, as well as helium retention and surface morphological evolution, toward optimal design of plasma facing components.« less

  4. Helium Pumping Wall for a Liquid Lithium Tokamak Richard Majeski |

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

    Princeton Plasma Physics Lab Helium Pumping Wall for a Liquid Lithium Tokamak Richard Majeski This invention is designed to be a subsystem of a device, a tokamak with walls or plasma facing components of liquid lithium. This approach to constructing the lithium-bearing walls of the tokamak allows the wall to fulfill a necessary function -- helium pumping - for which a complex structure was formerly required. The primary novel feature of the invention is that a permeable wall is used to

  5. Recovery of purified helium or hydrogen from gas mixtures

    DOE Patents [OSTI]

    Merriman, J.R.; Pashley, J.H.; Stephenson, M.J.; Dunthorn, D.I.

    1974-01-15

    A process is described for the removal of helium or hydrogen from gaseous mixtures also containing contaminants. The gaseous mixture is contacted with a liquid fluorocarbon in an absorption zone maintained at superatomspheric pressure to preferentially absorb the contaminants in the fluorocarbon. Unabsorbed gas enriched in hydrogen or helium is withdrawn from the absorption zone as product. Liquid fluorocarbon enriched in contaminants is withdrawn separately from the absorption zone. (10 claims)

  6. Process Options for Nominal 2-K Helium Refrigeration System Designs

    SciTech Connect (OSTI)

    Peter Knudsen, Venkatarao Ganni

    2012-07-01

    Nominal 2-K helium refrigeration systems are frequently used for superconducting radio frequency and magnet string technologies used in accelerators. This paper examines the trade-offs and approximate performance of four basic types of processes used for the refrigeration of these technologies; direct vacuum pumping on a helium bath, direct vacuum pumping using full or partial refrigeration recovery, cold compression, and hybrid compression (i.e., a blend of cold and warm sub-atmospheric compression).

  7. Helium Release Behavior of Aged Titanium Tritides

    SciTech Connect (OSTI)

    SHANAHAN, KIRKL.

    2004-07-27

    One sample of bulk Ti has been loaded with a 50 per cent / 50 per cent deuterium/tritium mixture and statically aged for 6.5 years. Thermal desorption of the sample shows an initial release of hydrogen isotopes followed by 3He release. Subsequent D2 loading/desorption was used to quantify the trapped tritium heel. The sample shows an excess hydrogen capacity as a second thermal desorption peak that partially disappears and shifts with annealing at 923-973K. The main hydrogen desorption peak also shifts to higher temperature, indicating a partial reversal of the tritium-decay induced damage by annealing.

  8. Helium Loop Cooling Channel Hydraulic Characterization

    SciTech Connect (OSTI)

    Olivas, Eric Richard; Morgan, Robert Vaughn; Woloshun, Keith Albert

    2015-07-02

    New methods for generating ⁹⁹Mo are being explored in an effort to eliminate proliferation issues and provide a domestic supply of ⁹⁹mTc for medical imaging. Electron accelerating technology is used by sending an electron beam through a series of ¹⁰⁰Mo targets. During this process a large amount of heat is created, which directly affects the operating temperature set for the system. In order to maintain the required temperature range, helium gas is used to serve as a cooling agent that flows through narrow channels between the target disks. Currently we are tailoring the cooling channel entrance and exits to decrease the pressure drop through the targets. Currently all hardware has be procured and manufactured to conduct flow measurements and visualization via solid particle seeder. Pressure drop will be studied as a function of mass flow and diffuser angle. The results from these experiments will help in determining target cooling geometry and validate CFD code results.

  9. Photochemical isotope separation

    DOE Patents [OSTI]

    Robinson, C.P.; Jensen, R.J.; Cotter, T.P.; Greiner, N.R.; Boyer, K.

    1987-04-28

    A process is described for separating isotopes by selective excitation of isotopic species of a volatile compound by tuned laser light. A highly cooled gas of the volatile compound is produced in which the isotopic shift is sharpened and defined. Before substantial condensation occurs, the cooled gas is irradiated with laser light precisely tuned to a desired wavelength to selectively excite a particular isotopic species in the cooled gas. The laser light may impart sufficient energy to the excited species to cause it to undergo photochemical reaction or even to photoionize. Alternatively, a two-photon irradiation may be applied to the cooled gas to induce photochemical reaction or photoionization. The process is particularly applicable to the separation of isotopes of uranium and plutonium. 8 figs.

  10. Laser isotope separation

    DOE Patents [OSTI]

    Robinson, C. Paul; Jensen, Reed J.; Cotter, Theodore P.; Boyer, Keith; Greiner, Norman R.

    1988-01-01

    A process and apparatus for separating isotopes by selective excitation of isotopic species of a volatile compound by tuned laser light. A highly cooled gas of the volatile compound is produced in which the isotopic shift is sharpened and defined. Before substantial condensation occurs, the cooled gas is irradiated with laser light precisely tuned to a desired wavelength to selectively excite a particular isotopic species in the cooled gas. The laser light may impart sufficient energy to the excited species to cause it to undergo photolysis, photochemical reaction or even to photoionize. Alternatively, a two-photon irradiation may be applied to the cooled gas to induce photolysis, photochemical reaction or photoionization. The process is particularly applicable to the separation of isotopes of uranium.

  11. Photochemical isotope separation

    DOE Patents [OSTI]

    Robinson, C. Paul; Jensen, Reed J.; Cotter, Theodore P.; Greiner, Norman R.; Boyer, Keith

    1987-01-01

    A process for separating isotopes by selective excitation of isotopic species of a volatile compound by tuned laser light. A highly cooled gas of the volatile compound is produced in which the isotopic shift is sharpened and defined. Before substantial condensation occurs, the cooled gas is irradiated with laser light precisely tuned to a desired wavelength to selectively excite a particular isotopic species in the cooled gas. The laser light may impart sufficient energy to the excited species to cause it to undergo photochemical reaction or even to photoionize. Alternatively, a two-photon irradiation may be applied to the cooled gas to induce photochemical reaction or photoionization. The process is particularly applicable to the separation of isotopes of uranium and plutonium.

  12. Laser isotope separation

    DOE Patents [OSTI]

    Robinson, C.P.; Reed, J.J.; Cotter, T.P.; Boyer, K.; Greiner, N.R.

    1975-11-26

    A process and apparatus for separating isotopes by selective excitation of isotopic species of a volatile compound by tuned laser light is described. A highly cooled gas of the volatile compound is produced in which the isotopic shift is sharpened and defined. Before substantial condensation occurs, the cooled gas is irradiated with laser light precisely tuned to a desired wavelength to selectively excite a particular isotopic species in the cooled gas. The laser light may impart sufficient energy to the excited species to cause it to undergo photolysis, photochemical reaction or even to photoionize. Alternatively, a two-photon irradiation may be applied to the cooled gas to induce photolysis, photochemical reaction or photoionization. The process is particularly applicable to the separation of isotopes of uranium.

  13. Science on Tap - Isotopes

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

    Science on Tap - Isotopes Science on Tap - Isotopes WHEN: Jun 16, 2016 5:30 PM - 7:00 PM WHERE: UnQuarked Wine Room 145 Central Park Square, Los Alamos, New Mexico 87544 USA CONTACT: Linda Anderman (505) 665-9196 CATEGORY: Bradbury INTERNAL: Calendar Login Event Description Short presentation followed by lively interaction on the topic at hand. While isotopes are chemical elements (think periodic table), their varying numbers of neutrons mean they can be used in lots of different way. Join us

  14. Industry Perspective

    Broader source: Energy.gov [DOE]

    Fuel cell and biogas industries perspectives. Presented by Mike Hicks, Fuel Cell and Hydrogen Energy Association, at the NREL/DOE Biogas and Fuel Cells Workshop held June 11-13, 2012, in Golden, Colorado.

  15. Measurement of the Helium Factors at Jlab

    SciTech Connect (OSTI)

    Elena Khrosinkova

    2007-06-11

    An experiment to measure elastic electron scattering off 3He and 4He at large momentum transfers is presented. The experiment was carried out in the Hall A Facility of Jefferson Lab. Elastic electron scattering off 3He was measured at forward and backward electron scattering angles to extract the isotope's charge and magnetic form factors. The charge form factor of 4He will be extracted from forward-angle electron scattering angle measurements. The data are expected to significantly extend and improve the existing measurements of the three-and four-body form factors. The results will be crucial for the establishment of a canonical standard model for the few- body nuclear systems and for testing predictions of quark dimensional scaling and hybrid nucleon- quark models.

  16. Atomic vapor laser isotope separation

    SciTech Connect (OSTI)

    Stern, R.C.; Paisner, J.A.

    1986-08-15

    The atomic vapor laser isotope separation (AVLIS) process for the enrichment of uranium is evaluated. (AIP)

  17. Plasma isotope separation methods

    SciTech Connect (OSTI)

    Grossman, M.W. ); Shepp, T.A. )

    1991-12-01

    Isotope separation has many important industrial, medical, and research applications. Large-scale processes have typically utilized complex cascade systems; for example, the gas centrifuge. Alternatively, high single-stage enrichment processes (as in the case of the calutron) are very energy intensive. Plasma-based methods being developed for the past 15 to 20 years have attempted to overcome these two drawbacks. In this review, six major types of isotope separation methods which involve plasma phenomena are discussed. These methods are: plasma centrifuge, AVLIS (atomic vapor laser isotope separation), ion wave, ICR (ion-cyclotron resonance), calutron, and gas discharge. The emphasis of this paper is to describe the plasma phenomena in these major categories. An attempt was made to include enough references so that more detailed study or evaluation of a particular method could readily be pursued. A brief discussion of isotope separation using mass balance concepts is also carried out.

  18. Helium gas bubble trapped in liquid helium in high magnetic field

    SciTech Connect (OSTI)

    Bai, H. Hannahs, S. T.; Markiewicz, W. D.; Weijers, H. W.

    2014-03-31

    High magnetic field magnets are used widely in the area of the condensed matter physics, material science, chemistry, geochemistry, and biology at the National High Magnetic Field Laboratory. New high field magnets of state-of-the-art are being pursued and developed at the lab, such as the current developing 32 T, 32 mm bore fully superconducting magnet. Liquid Helium (LHe) is used as the coolant for superconducting magnets or samples tested in a high magnetic field. When the magnetic field reaches a relatively high value the boil-off helium gas bubble generated by heat losses in the cryostat can be trapped in the LHe bath in the region where BzdBz/dz is less than negative 2100 T{sup 2}/m, instead of floating up to the top of LHe. Then the magnet or sample in the trapped bubble region may lose efficient cooling. In the development of the 32 T magnet, a prototype Yttrium Barium Copper Oxide coil of 6 double pancakes with an inner diameter of 40 mm and an outer diameter of 140 mm was fabricated and tested in a resistive magnet providing a background field of 15 T. The trapped gas bubble was observed in the tests when the prototype coil was ramped up to 7.5 T at a current of 200 A. This letter reports the test results on the trapped gas bubble and the comparison with the analytical results which shows they are in a good agreement.

  19. Controlled Chemistry Helium High Temperature Materials Test Loop

    SciTech Connect (OSTI)

    Richard N. WRight

    2005-08-01

    A system to test aging and environmental effects in flowing helium with impurity content representative of the Next Generation Nuclear Plant (NGNP) has been designed and assembled. The system will be used to expose microstructure analysis coupons and mechanical test specimens for up to 5,000 hours in helium containing potentially oxidizing or carburizing impurities controlled to parts per million levels. Impurity levels in the flowing helium are controlled through a feedback mechanism based on gas chromatography measurements of the gas chemistry at the inlet and exit from a high temperature retort containing the test materials. Initial testing will focus on determining the nature and extent of combined aging and environmental effects on microstructure and elevated temperature mechanical properties of alloys proposed for structural applications in the NGNP, including Inconel 617 and Haynes 230.

  20. Operation of drift chambers with helium based mixtures

    SciTech Connect (OSTI)

    Sharma, A. ); Sauli, F. )

    1994-08-01

    Helium based gas mixtures have been investigated for lowering multiple scattering contributions to the momentum resolution for intermediate energy particles. The relevant transport parameters, namely drift velocity and diffusion have been calculated for several mixtures and compared to standard argon based mixtures. Some fast, low diffusion mixtures have been identified. The small Lorentz angle computed make them promising candidates for drift chamber operation in magnetic fields. Measurements on high accuracy drift chambers in a test beam with a helium-DME (dimethyl ether) (70-30) mixture have resulted in a spatial resolution ranging from 70[mu]m to 100[mu]m.

  1. Status of the helium afterglow injector for MAMI

    SciTech Connect (OSTI)

    Arianer, J.; Cohen, S.; Essabaa, S.; Frascaria, R.; Zerhouni, O.; Szeremeta, F.; Wurzinger, R.; Aulenbacher, K.

    1998-01-20

    For the parity-violation experiment at the Mami cw electron accelerator facility at the University of Mainz, we need a stable polarized electron source able to deliver a current >150 {mu}A with polarization >60%. We develop the Orsay polarized electron source SELPO as an injector for MAMI. SELPO source based on a flowing helium afterglow is now operating in a high voltage platform. The terminal will be tested completely at Orsay and is foreseen to be installed at MAMI before the end of this year. Recent results obtained with an array of capillaries to generate the helium flow and a longitudinal spin direction are described.

  2. Statistical properties of inter-series mixing in helium: From integrability to chaos

    SciTech Connect (OSTI)

    Puttner, R; Gremaud, B.; Delande, D.; Domke, M.; Martins, M.; Schlachter, A.S.; Kaindl, G.

    2001-04-23

    The photoionization spectrum of helium near the double-ionization threshold shows structure which indicated a transition towards quantum chaos.

  3. Laser induced fluorescence spectroscopy of the Ca dimer deposited on helium and mixed helium/xenon clusters

    SciTech Connect (OSTI)

    Gaveau, Marc-André; Pothier, Christophe; Briant, Marc; Mestdagh, Jean-Michel

    2014-12-09

    We study how the laser induced fluorescence spectroscopy of the calcium dimer deposited on pure helium clusters is modified by the addition of xenon atoms. In the wavelength range between 365 and 385 nm, the Ca dimer is excited from its ground state up to two excited electronic states leading to its photodissociation in Ca({sup 1}P)+Ca({sup 1}S): this process is monitored by recording the Ca({sup 1}P) fluorescence at 422.7nm. One of these electronic states of Ca{sub 2} is a diexcited one correlating to the Ca(4s4p{sup 3}P(+Ca(4s3d{sup 3}D), the other one is a repulsive state correlating to the Ca(4s4p1P)+Ca(4s21S) asymptote, accounting for the dissociation of Ca{sub 2} and the observation of the subsequent Ca({sup 1}P) emission. On pure helium clusters, the fluorescence exhibits the calcium atomic resonance line Ca({sup 1}S←{sup 1}P) at 422.7 nm (23652 cm{sup −1}) assigned to ejected calcium, and a narrow red sided band corresponding to calcium that remains solvated on the helium cluster. When adding xenon atoms to the helium clusters, the intensity of these two features decreases and a new spectral band appears on the red side of calcium resonance line; the intensity and the red shift of this component increase along with the xenon quantity deposited on the helium cluster: it is assigned to the emission of Ca({sup 1}P) associated with the small xenon aggregate embedded inside the helium cluster.

  4. Metal hydride differential scanning calorimetry as an approach to compositional determination of mixtures of hydrogen isotopologues and helium

    SciTech Connect (OSTI)

    Robinson, David B.; Luo, Weifang; Cai, Trevor Y.; Stewart, Kenneth D.

    2015-09-26

    Gaseous mixtures of diatomic hydrogen isotopologues and helium are often encountered in the nuclear energy industry and in analytical chemistry. Compositions of stored mixtures can vary due to interactions with storage and handling materials. When tritium is present, it decays to form ions and helium-3, both of which can lead to further compositional variation. Monitoring of composition is typically achieved by mass spectrometry, a method that is bulky and energy-intensive. Mass spectrometers disperse sample material through vacuum pumps, which is especially troublesome if tritium is present. Moreover, our ultimate goal is to create a compact, fast, low-power sensor that can determine composition with minimal gas consumption and waste generation, as a complement to mass spectrometry that can be instantiated more widely. We propose calorimetry of metal hydrides as an approach to this, due to the strong isotope effect on gas absorption, and demonstrate the sensitivity of measured heat flow to atomic composition of the gas. Peak shifts are discernible when mole fractions change by at least 1%. A mass flow restriction results in a unique dependence of the measurement on helium concentration. We present a mathematical model as a first step toward prediction of the peak shapes and positions. The model includes a useful method to compute estimates of phase diagrams for palladium in the presence of arbitrary mixtures of hydrogen isotopologues. As a result, we expect that this approach can be used to deduce unknown atomic compositions from measured calorimetric data over a useful range of partial pressures of each component.

  5. Metal hydride differential scanning calorimetry as an approach to compositional determination of mixtures of hydrogen isotopologues and helium

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

    Robinson, David B.; Luo, Weifang; Cai, Trevor Y.; Stewart, Kenneth D.

    2015-09-26

    Gaseous mixtures of diatomic hydrogen isotopologues and helium are often encountered in the nuclear energy industry and in analytical chemistry. Compositions of stored mixtures can vary due to interactions with storage and handling materials. When tritium is present, it decays to form ions and helium-3, both of which can lead to further compositional variation. Monitoring of composition is typically achieved by mass spectrometry, a method that is bulky and energy-intensive. Mass spectrometers disperse sample material through vacuum pumps, which is especially troublesome if tritium is present. Moreover, our ultimate goal is to create a compact, fast, low-power sensor that canmore » determine composition with minimal gas consumption and waste generation, as a complement to mass spectrometry that can be instantiated more widely. We propose calorimetry of metal hydrides as an approach to this, due to the strong isotope effect on gas absorption, and demonstrate the sensitivity of measured heat flow to atomic composition of the gas. Peak shifts are discernible when mole fractions change by at least 1%. A mass flow restriction results in a unique dependence of the measurement on helium concentration. We present a mathematical model as a first step toward prediction of the peak shapes and positions. The model includes a useful method to compute estimates of phase diagrams for palladium in the presence of arbitrary mixtures of hydrogen isotopologues. As a result, we expect that this approach can be used to deduce unknown atomic compositions from measured calorimetric data over a useful range of partial pressures of each component.« less

  6. Transportation of medical isotopes

    SciTech Connect (OSTI)

    Nielsen, D.L.

    1997-11-19

    A Draft Technical Information Document (HNF-1855) is being prepared to evaluate proposed interim tritium and medical isotope production at the Fast Flux Test Facility (FFTF). This assessment examines the potential health and safety impacts of transportation operations associated with the production of medical isotopes. Incident-free and accidental impacts are assessed using bounding source terms for the shipment of nonradiological target materials to the Hanford Site, the shipment of irradiated targets from the FFTF to the 325 Building, and the shipment of medical isotope products from the 325 Building to medical distributors. The health and safety consequences to workers and the public from the incident-free transportation of targets and isotope products would be within acceptable levels. For transportation accidents, risks to works and the public also would be within acceptable levels. This assessment is based on best information available at this time. As the medical isotope program matures, this analysis will be revised, if necessary, to support development of a final revision to the Technical Information Document.

  7. Separation of sulfur isotopes

    DOE Patents [OSTI]

    DeWitt, Robert; Jepson, Bernhart E.; Schwind, Roger A.

    1976-06-22

    Sulfur isotopes are continuously separated and enriched using a closed loop reflux system wherein sulfur dioxide (SO.sub.2) is reacted with sodium hydroxide (NaOH) or the like to form sodium hydrogen sulfite (NaHSO.sub.3). Heavier sulfur isotopes are preferentially attracted to the NaHSO.sub.3, and subsequently reacted with sulfuric acid (H.sub.2 SO.sub.4) forming sodium hydrogen sulfate (NaHSO.sub.4) and SO.sub.2 gas which contains increased concentrations of the heavier sulfur isotopes. This heavy isotope enriched SO.sub.2 gas is subsequently separated and the NaHSO.sub.4 is reacted with NaOH to form sodium sulfate (Na.sub.2 SO.sub.4) which is subsequently decomposed in an electrodialysis unit to form the NaOH and H.sub.2 SO.sub.4 components which are used in the aforesaid reactions thereby effecting sulfur isotope separation and enrichment without objectionable loss of feed materials.

  8. An investigation of thermally driven acoustical oscillations in helium systems

    SciTech Connect (OSTI)

    Fuerst, J.D.

    1990-08-01

    The phenomenon of thermal-acoustic oscillation is seen to arise spontaneously in gas columns subjected to steep temperature gradients, particularly in tubes connecting liquid helium reservoirs with the ambient environment. This if often the arrangement for installed cryogenic instrumentation and is accompanied by undesirably large heat transfer rates to the cold region. Experimental data are collected and matched to theoretical predictions of oscillatory behavior; these results are in good agreement with the analytical model and with previously collected data. The present experiment places the open ends of oscillating tubes of the various lengths and cross sections in communication with flowing helium in the subcooled, 2-phase, or superheated state while the other ends are maintained at some controlled, elevated temperature. Assorted cold end conditions are achieved through adjustments to the Fermilab Tevatron satellite test refrigerator to which the test cryostat is connected. The warm, closed ends of the tubes are maintained by isothermal baths of liquid nitrogen, ice water, and boiling water. The method is contrasted to previous arrangements whereby tubes are run from room temperature into or adjacent to a stagnant pool of liquid helium. Additionally, the effect of pulsations in the flowing helium stream is explored through operation of the refrigerator's wet and dry expanders during data collection. These data confirm the theory to which try were compared and support its use in the design of cryogenic sensing lines for avoidance of thermoacoustic oscillation.

  9. TRANSMISSION ELECTRON MICROSCOPY STUDY OF HELIUM BEARING FUSION WELDS

    SciTech Connect (OSTI)

    Tosten, M; Michael Morgan, M

    2008-12-12

    A transmission electron microscopy (TEM) study was conducted to characterize the helium bubble distributions in tritium-charged-and-aged 304L and 21Cr-6Ni-9Mn stainless steel fusion welds containing approximately 150 appm helium-3. TEM foils were prepared from C-shaped fracture toughness test specimens containing {delta} ferrite levels ranging from 4 to 33 volume percent. The weld microstructures in the low ferrite welds consisted mostly of austenite and discontinuous, skeletal {delta} ferrite. In welds with higher levels of {delta} ferrite, the ferrite was more continuous and, in some areas of the 33 volume percent sample, was the matrix/majority phase. The helium bubble microstructures observed were similar in all samples. Bubbles were found in the austenite but not in the {delta} ferrite. In the austenite, bubbles had nucleated homogeneously in the grain interiors and heterogeneously on dislocations. Bubbles were not found on any austenite/austenite grain boundaries or at the austenite/{delta} ferrite interphase interfaces. Bubbles were not observed in the {delta} ferrite because of the combined effects of the low solubility and rapid diffusion of tritium through the {delta} ferrite which limited the amount of helium present to form visible bubbles.

  10. Isotope separation apparatus

    DOE Patents [OSTI]

    Arnush, Donald; MacKenzie, Kenneth R.; Wuerker, Ralph F.

    1980-01-01

    Isotope separation apparatus consisting of a plurality of cells disposed adjacent to each other in an evacuated container. A common magnetic field is established extending through all of the cells. A source of energetic electrons at one end of the container generates electrons which pass through the cells along the magnetic field lines. Each cell includes an array of collector plates arranged in parallel or in tandem within a common magnetic field. Sets of collector plates are disposed adjacent to each other in each cell. Means are provided for differentially energizing ions of a desired isotope by applying energy at the cyclotron resonant frequency of the desired isotope. As a result, the energized desired ions are preferentially collected by the collector plates.

  11. DEEP WATER ISOTOPIC CURRENT ANALYZER

    DOE Patents [OSTI]

    Johnston, W.H.

    1964-04-21

    A deepwater isotopic current analyzer, which employs radioactive isotopes for measurement of ocean currents at various levels beneath the sea, is described. The apparatus, which can determine the direction and velocity of liquid currents, comprises a shaft having a plurality of radiation detectors extending equidistant radially therefrom, means for releasing radioactive isotopes from the shaft, and means for determining the time required for the isotope to reach a particular detector. (AEC)

  12. Method for separating boron isotopes

    DOE Patents [OSTI]

    Rockwood, Stephen D.

    1978-01-01

    A method of separating boron isotopes .sup.10 B and .sup.11 B by laser-induced selective excitation and photodissociation of BCl.sub.3 molecules containing a particular boron isotope. The photodissociation products react with an appropriate chemical scavenger and the reaction products may readily be separated from undissociated BCl.sub.3, thus effecting the desired separation of the boron isotopes.

  13. Source localization of brain activity using helium-free interferometer

    SciTech Connect (OSTI)

    Dammers, Jürgen Chocholacs, Harald; Eich, Eberhard; Boers, Frank; Faley, Michael; Dunin-Borkowski, Rafal E.; Jon Shah, N.

    2014-05-26

    To detect extremely small magnetic fields generated by the human brain, currently all commercial magnetoencephalography (MEG) systems are equipped with low-temperature (low-T{sub c}) superconducting quantum interference device (SQUID) sensors that use liquid helium for cooling. The limited and increasingly expensive supply of helium, which has seen dramatic price increases recently, has become a real problem for such systems and the situation shows no signs of abating. MEG research in the long run is now endangered. In this study, we report a MEG source localization utilizing a single, highly sensitive SQUID cooled with liquid nitrogen only. Our findings confirm that localization of neuromagnetic activity is indeed possible using high-T{sub c} SQUIDs. We believe that our findings secure the future of this exquisitely sensitive technique and have major implications for brain research and the developments of cost-effective multi-channel, high-T{sub c} SQUID-based MEG systems.

  14. Quantum entanglement for helium atom in the Debye plasmas

    SciTech Connect (OSTI)

    Lin, Yen-Chang; Fang, Te-Kuei; Ho, Yew Kam

    2015-03-15

    In the present work, we present an investigation on quantum entanglement of the two-electron helium atom immersed in weakly coupled Debye plasmas, modeled by the Debye-Hckel, or screened Coulomb, potential to mimic the interaction between two charged particles inside the plasma. Quantum entanglement is related to correlation effects in a multi-particle system. In a bipartite system, a measurement made on one of the two entangled particles affects the outcome of the other particle, even if such two particles are far apart. Employing wave functions constructed with configuration interaction B-spline basis, we have quantified von Neumann entropy and linear entropy for a series of He {sup 1,3}S{sup e} and {sup 1,3}P{sup o} states in plasma-embedded helium atom.

  15. Effect of Helium Accumulation on the Spent Fuel Microstructure

    SciTech Connect (OSTI)

    Ferry, Cecile; Piron, Jean-Paul; Stout, Ray

    2007-07-01

    In a nuclear spent fuel repository, the aqueous rapid release of radio-activity from exposed spent fuel surfaces will depend on the pellet microstructure at the arrival time of water into the disposal container. Research performed on spent fuel evolution in a closed system has shown that the evolution of microstructure under disposal conditions should be governed by the cumulated {alpha}-decay damage and the subsequent helium behavior. The evolution of fission gas bubble characteristics under repository conditions has to be assessed. In UO{sub 2} fuels with a burnup of 47.5 GWd/t, the pressure in fission gas bubbles, including the pressure increase from {alpha}-decay helium atoms, is not expected to reach the critical bubble pressure that will cause failure, thus micro-cracking in UO{sub 2} spent fuel grains is not expected. (authors)

  16. Elastic Electron Scattering from Tritium and Helium-3

    DOE R&D Accomplishments [OSTI]

    Collard, H.; Hofstadter, R.; Hughes, E. B.; Johansson, A.; Yearian, M. R.; Day, R. B.; Wagner, R. T.

    1964-10-01

    The mirror nuclei of tritium and helium-3 have been studied by the method of elastic electron scattering. Absolute cross sections have been measured for incident electron energies in the range 110 - 690 MeV at scattering angles lying between 40 degrees and 135 degrees in this energy range. The data have been interpreted in a straightforward manner and form factors are given for the distributions of charge and magnetic moment in the two nuclei over a range of four-momentum transfer squared 1.0 - 8.0 F{sup -2}. Model-independent radii of the charge and magnetic moment distributions are given and an attempt is made to deduce form factors describing the spatial distribution of the protons in tritium and helium-3.

  17. Investigation of Cellular Interactions of Nanoparticles by Helium Ion Microscopy

    SciTech Connect (OSTI)

    Arey, Bruce W.; Shutthanandan, V.; Xie, Yumei; Tolic, Ana; Williams, Nolann G.; Orr, Galya

    2011-06-01

    The helium ion mircroscope (HIM) probes light elements (e.g. C, N, O, P) with high contrast due to the large variation in secondary electron yield, which minimizes the necessity of specimen staining. A defining characteristic of HIM is its remarkable capability to neutralize charge by the implementation of an electron flood gun, which eliminates the need for coating non-conductive specimens for imaging at high resolution. In addition, the small convergence angle in HeIM offers a large depth of field (~5x FE-SEM), enabling tall structures to be viewed in focus within a single image. Taking advantage of these capabilities, we investigate the interactions of engineered nanoparticles (NPs) at the surface of alveolar type II epithelial cells grown at the air-liquid interface (ALI). The increasing use of nanomaterials in a wide range of commercial applications has the potential to increase human exposure to these materials, but the impact of such exposure on human health is still unclear. One of the main routs of exposure is the respiratory tract, where alveolar epithelial cells present a vulnerable target at the interface with ambient air. Since the cellular interactions of NPs govern the cellular response and ultimately determine the impact on human health, our studies will help delineating relationships between particle properties and cellular interactions and response to better evaluate NP toxicity or biocompatibility. The Rutherford backscattered ion (RBI) is a helium ions imaging mode, which backscatters helium ions from every element except hydrogen, with a backscatter yield that depends on the atomic number of the target. Energy-sensitive backscatter analysis is being developed, which when combined with RBI image information, supports elemental identification at helium ion nanometer resolution. This capability will enable distinguishing NPs from cell surface structures with nanometer resolution.

  18. Mathematical modeling of a Fermilab helium liquefier coldbox

    SciTech Connect (OSTI)

    Geynisman, M.G.; Walker, R.J.

    1995-12-01

    Fermilab Central Helium Liquefier (CHL) facility is operated 24 hours-a-day to supply 4.6{degrees}K for the Fermilab Tevatron superconducting proton-antiproton collider Ring and to recover warm return gases. The centerpieces of the CHL are two independent cold boxes rated at 4000 and 5400 liters/hour with LN{sub 2} precool. These coldboxes are Claude cycle and have identical heat exchangers trains, but different turbo-expanders. The Tevatron cryogenics demand for higher helium supply from CHL was the driving force to investigate an installation of an expansion engine in place of the Joule-Thompson valve. A mathematical model was developed to describe the thermo- and gas-dynamic processes for the equipment included in the helium coldbox. The model is based on a finite element approach, opposite to a global variables approach, thus providing for higher accuracy and conversion stability. Though the coefficients used in thermo- and gas-dynamic equations are unique for a given coldbox, the general approach, the equations, the methods of computations, and most of the subroutines written in FORTRAN can be readily applied to different coldboxes. The simulation results are compared against actual operating data to demonstrate applicability of the model.

  19. Multiple reheat helium Brayton cycles for sodium fast reactors

    SciTech Connect (OSTI)

    Haihua Zhao; Per F. Peterson

    2008-07-01

    Sodium fast reactors (SFR) traditionally adopt the steam Rankine cycle for power conversion. The resulting potential for water-sodium reaction remains a continuing concern which at least partly delays the SFR technology commercialization and is a contributor to higher capital cost. Supercritical CO2 provides an alternative, but is also capable of sustaining energetic chemical reactions with sodium. Recent development on advanced inert-gas Brayton cycles could potentially solve this compatibility issue, increase thermal efficiency, and bring down the capital cost close to light water reactors. In this paper, helium Brayton cycles with multiple reheat and intercooling states are presented for SFRs with reactor outlet temperatures in the range of 510°C to 650°C. The resulting thermal efficiencies range from 39% and 47%, which is comparable with supercritical recompression CO2 cycles (SCO2 cycle). A systematic comparison between multiple reheat helium Brayton cycle and the SCO2 cycle is given, considering compatibility issues, plant site cooling temperature effect on plant efficiency, full plant cost optimization, and other important factors. The study indicates that the multiple reheat helium cycle is the preferred choice over SCO2 cycle for sodium fast reactors.

  20. ISOTOPE SEPARATING APPARATUS CONTROL

    DOE Patents [OSTI]

    Barnes, S.W.

    1959-08-25

    An improved isotope separating apparatus of the electromagnetic type, commonly referred to as a calutron, is described. Improvements in detecting and maintaining optimum position and focus of the ion beam are given. The calutron collector is provided with an additional electrode insulated from and positioned between the collecting pockets. The ion beams are properly positioned and focused until the deionizing current which flows from ground to this additional electrode ts a minimum.

  1. Helium-Based Soundwave Chiller: Trillium: A Helium-Based Sonic Chiller- Tons of Freezing with 0 GWP Refrigerants

    SciTech Connect (OSTI)

    2010-09-01

    BEETIT Project: Penn State is designing a freezer that substitutes the use of sound waves and environmentally benign refrigerant for synthetic refrigerants found in conventional freezers. Called a thermoacoustic chiller, the technology is based on the fact that the pressure oscillations in a sound wave result in temperature changes. Areas of higher pressure raise temperatures and areas of low pressure decrease temperatures. By carefully arranging a series of heat exchangers in a sound field, the chiller is able to isolate the hot and cold regions of the sound waves. Penn State’s chiller uses helium gas to replace synthetic refrigerants. Because helium does not burn, explode or combine with other chemicals, it is an environmentally-friendly alternative to other polluting refrigerants. Penn State is working to apply this technology on a large scale.

  2. Industry Perspective

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

    idatech.com info@idatech.com 63065 NE 18 th Street Bend, OR 97701 541.383.3390 Industry Perspective Biogas and Fuel Cell Workshop National Renewable Energy Laboratory June 11 - 13, 2012 Mike Hicks Chairman of the Board of Directors, FCHEA Treasurer of the Board of Directors, FCS&E Engineering Manager, Technology Development & Integration, IdaTech Outline 1. Critical Factors * Fuel Purity * Fuel Cost 2. Natural Gas - The Wild Card & Competition 3. IdaTech's Experience Implementing

  3. Laser isotope separation of erbium and other isotopes

    DOE Patents [OSTI]

    Haynam, Christopher A.; Worden, Earl F.

    1995-01-01

    Laser isotope separation is accomplished using at least two photoionization pathways of an isotope simultaneously, where each pathway comprises two or more transition steps. This separation method has been applied to the selective photoionization of erbium isotopes, particularly for the enrichment of .sup.167 Er. The hyperfine structure of .sup.167 Er was used to find two three-step photoionization pathways having a common upper energy level.

  4. Laser isotope separation of erbium and other isotopes

    DOE Patents [OSTI]

    Haynam, C.A.; Worden, E.F.

    1995-08-22

    Laser isotope separation is accomplished using at least two photoionization pathways of an isotope simultaneously, where each pathway comprises two or more transition steps. This separation method has been applied to the selective photoionization of erbium isotopes, particularly for the enrichment of {sup 167}Er. The hyperfine structure of {sup 167}Er was used to find two three-step photoionization pathways having a common upper energy level. 3 figs.

  5. Helium-cooled solid breeder blanket design for a tokamak fusion reactor

    SciTech Connect (OSTI)

    Huggenberger, M.; Schultz, K.R.

    1983-11-01

    A preliminary design for a helium-cooled solid breeder blanket for a tokamak fusion reactor has been developed, and its performance looks quite good. The design is capable of bearing a 4 MW/m/sup 2/ neutron wall load, and the ideal pumping power required for the whole primary helium loop including the steam generators is only 2.5% of the total thermal power. The maximum blanket thickness including the helium duct work is only 860 mm, the minimum thickness is only 730 mm. The design work was focused on the thermalhydraulic aspects, which represent the key problems associated with using helium as a coolant. The present work demonstrates that the potential disadvantages helium has, due to its limited heat transfer capabilities, can be avoided or minimized by an appropriate thermal-hydraulic design. As a result, helium with its many advantages remains a promising fusion blanket coolant.

  6. Asteroseismic estimate of helium abundance of a solar analog binary system

    SciTech Connect (OSTI)

    Verma, Kuldeep; Antia, H. M.; Faria, Joo P.; Monteiro, Mrio J. P. F. G.; Basu, Sarbani; Mazumdar, Anwesh; Appourchaux, Thierry; Chaplin, William J.; Garca, Rafael A.

    2014-08-01

    16 Cyg A and B are among the brightest stars observed by Kepler. What makes these stars more interesting is that they are solar analogs. 16 Cyg A and B exhibit solar-like oscillations. In this work we use oscillation frequencies obtained using 2.5 yr of Kepler data to determine the current helium abundance of these stars. For this we use the fact that the helium ionization zone leaves a signature on the oscillation frequencies and that this signature can be calibrated to determine the helium abundance of that layer. By calibrating the signature of the helium ionization zone against models of known helium abundance, the helium abundance in the envelope of 16 Cyg A is found to lie in the range of 0.231 to 0.251 and that of 16 Cyg B lies in the range of 0.218 to 0.266.

  7. Production of carbon monoxide-free hydrogen and helium from a high-purity source

    DOE Patents [OSTI]

    Golden, Timothy Christopher; Farris, Thomas Stephen

    2008-11-18

    The invention provides vacuum swing adsorption processes that produce an essentially carbon monoxide-free hydrogen or helium gas stream from, respectively, a high-purity (e.g., pipeline grade) hydrogen or helium gas stream using one or two adsorber beds. By using physical adsorbents with high heats of nitrogen adsorption, intermediate heats of carbon monoxide adsorption, and low heats of hydrogen and helium adsorption, and by using vacuum purging and high feed stream pressures (e.g., pressures of as high as around 1,000 bar), pipeline grade hydrogen or helium can purified to produce essentially carbon monoxide -free hydrogen and helium, or carbon monoxide, nitrogen, and methane-free hydrogen and helium.

  8. Stable isotope research pool inventory

    SciTech Connect (OSTI)

    Not Available

    1988-02-01

    This report contains a listing of electromagnetically separated stable isotopes which are available at the Oak Ridge National Laboratory for distribution for nondestructive research use on a loan basis. This inventory includes all samples of stable isotopes in the Research Materials Collection and does not designate whether a sample is out on loan or is in reprocessing. For some of the high-abundance, naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56.

  9. Stable isotope research pool inventory

    SciTech Connect (OSTI)

    Not Available

    1982-01-01

    This report contains a listing of electromagnetically separated stable isotopes which are available for distribution within the United States for nondestructive research use from the Oak Ridge National Laboratory on a loan basis. This inventory includes all samples of stable isotopes in the Material Research Collection and does not designate whether a sample is out on loan or in reprocessing. For some of the high abundance naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56.

  10. Stable isotope research pool inventory

    SciTech Connect (OSTI)

    Not Available

    1984-03-01

    This report contains a listing of electromagnetically separated stable isotopes which are available at the Oak Ridge National Laboratory for distribution for nondestructive research use on a loan basis. This inventory includes all samples of stable isotopes in the Research Materials Collection and does not designate whether a sample is out on loan or is in reprocessing. For some of the high abundance naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56.

  11. Isotopically labeled compositions and method

    DOE Patents [OSTI]

    Schmidt, Jurgen G.; Kimball, David B.; Alvarez, Marc A.; Williams, Robert F.; Martinez, Rudolfo A.

    2011-07-12

    Compounds having stable isotopes .sup.13C and/or .sup.2H were synthesized from precursor compositions having solid phase supports or affinity tags.

  12. Development of a high-density gas-jet target for nuclear astrophysics and reaction studies with rare isotope beams. Final Report

    SciTech Connect (OSTI)

    Uwe, Greife

    2014-08-12

    The purpose of this project was to develop a high-density gas jet target that will enable a new program of transfer reaction studies with rare isotope beams and targets of hydrogen and helium that is not currently possible and will have an important impact on our understanding of stellar explosions and of the evolution of nuclear shell structure away from stability. This is the final closeout report for the project.

  13. Interim Report on the Optimization and Feasibility Studies for the Neutron Detection without Helium-3 Project

    SciTech Connect (OSTI)

    Ely, James H.

    2012-03-19

    This report provides the status and results of the first year's effort in modeling and simulation to investigate alternatives to helium-3 for neutron detection in safeguards applications.

  14. Ultra high vacuum pumping system and high sensitivity helium leak detector

    DOE Patents [OSTI]

    Myneni, G.R.

    1997-12-30

    An improved helium leak detection method and apparatus are disclosed which increase the leak detection sensitivity to 10{sup {minus}13} atm cc/s. The leak detection sensitivity is improved over conventional leak detectors by completely eliminating the use of o-rings, equipping the system with oil-free pumping systems, and by introducing measured flows of nitrogen at the entrances of both the turbo pump and backing pump to keep the system free of helium background. The addition of dry nitrogen flows to the system reduces back streaming of atmospheric helium through the pumping system as a result of the limited compression ratios of the pumps for helium. 2 figs.

  15. Energy-related applications of helium: a revision of the ERDA-13 data base

    SciTech Connect (OSTI)

    Hammel, E.F.; Krupka, M.C.

    1980-08-01

    A re-examination, revision, and re-evaluation of the data base contained within the 1975 document, ERDA-13, The Energy-Related Applications of Helium, were completed and results are presented in this report. New technical and resource data, current legislative proposals, updated supply-and-demand relationships, latest legal developments, programmatic changes affectng the future demand for helium, socio-economic aspects, and the effects of the latest energy-consumption projections were considered and are discussed. In contrast to ERDA-13, however, explicit recommendations with respect to the formulation of Federal helium policy, as it pertains to the energy-related applications of helium, are not given.

  16. Ultra high vacuum pumping system and high sensitivity helium leak detector

    DOE Patents [OSTI]

    Myneni, Ganapati Rao

    1997-01-01

    An improved helium leak detection method and apparatus are disclosed which increase the leak detection sensitivity to 10.sup.-13 atm cc s.sup.-1. The leak detection sensitivity is improved over conventional leak detectors by completely eliminating the use of o-rings, equipping the system with oil-free pumping systems, and by introducing measured flows of nitrogen at the entrances of both the turbo pump and backing pump to keep the system free of helium background. The addition of dry nitrogen flows to the system reduces backstreaming of atmospheric helium through the pumping system as a result of the limited compression ratios of the pumps for helium.

  17. Theory of Positron Annihilation in Helium-Filled Bubbles in Plutonium...

    Office of Scientific and Technical Information (OSTI)

    Theory of Positron Annihilation in Helium-Filled Bubbles in Plutonium Citation Details ... This method is capable of treating system cell sizes of several thousand atoms, allowing ...

  18. Advanced isotope separation

    SciTech Connect (OSTI)

    Not Available

    1982-05-04

    The Study Group briefly reviewed the technical status of the three Advanced Isotope Separation (AIS) processes. It also reviewed the evaluation work that has been carried out by DOE's Process Evaluation Board (PEB) and the Union Carbide Corporation-Nuclear Division (UCCND). The Study Group briefly reviewed a recent draft assessment made for DOE staff of the nonproliferation implications of the AIS technologies. The staff also very briefly summarized the status of GCEP and Advanced Centrifuge development. The Study Group concluded that: (1) there has not been sufficient progress to provide a firm scientific, technical or economic basis on which to select one of the three competing AIS processes for full-scale engineering development at this time; and (2) however, should budgetary restraints or other factors force such a selection, we believe that the evaluation process that is being carried out by the PEB provides the best basis available for making a decision. The Study Group recommended that: (1) any decisions on AIS processes should include a comparison with gas centrifuge processes, and should not be made independently from the plutonium isotope program; (2) in evaluating the various enrichment processes, all applicable costs (including R and D and sales overhead) and an appropriate discounting approach should be included in order to make comparisons on a private industry basis; (3) if the three AIS programs continue with limited resources, the work should be reoriented to focus only on the most pressing technical problems; and (4) if a decision is made to develop the Atomic Vapor Laser Isotope Separation process, the solid collector option should be pursued in parallel to alleviate the potential program impact of liquid collector thermal control problems.

  19. Chromatographic hydrogen isotope separation

    DOE Patents [OSTI]

    Aldridge, F.T.

    Intermetallic compounds with the CaCu/sub 5/ type of crystal structure, particularly LaNiCo/sub 4/ and CaNi/sub 5/, exhibit high separation factors and fast equilibrium times and therefore are useful for packing a chromatographic hydrogen isotope separation column. The addition of an inert metal to dilute the hydride improves performance of the column. A large scale multi-stage chromatographic separation process run as a secondary process off a hydrogen feedstream from an industrial plant which uses large volumes of hydrogen cn produce large quantities of heavy water at an effective cost for use in heavy water reactors.

  20. ISOTOPE FRACTIONATION PROCESS

    DOE Patents [OSTI]

    Clewett, G.H.; Lee, DeW.A.

    1958-05-20

    A new method is described for isotopic enrichment of uranium. It has been found that when an aqueous acidic solution of ionic tetravalent uraniunn is contacted with chelate complexed tetravalent uranium, the U/sup 238/ preferentially concentrates in the complexed phase while U/sup 235/ concentrates in the ionic phase. The effect is enhanced when the chelate compound is water insoluble and is dissolved in a water-immiscible organic solvent. Cupferron is one of a number of sultable complexing agents, and chloroform is a suitable organic solvent.

  1. Chromatographic hydrogen isotope separation

    DOE Patents [OSTI]

    Aldridge, Frederick T.

    1981-01-01

    Intermetallic compounds with the CaCu.sub.5 type of crystal structure, particularly LaNiCo.sub.4 and CaNi.sub.5, exhibit high separation factors and fast equilibrium times and therefore are useful for packing a chromatographic hydrogen isotope separation colum. The addition of an inert metal to dilute the hydride improves performance of the column. A large scale mutli-stage chromatographic separation process run as a secondary process off a hydrogen feedstream from an industrial plant which uses large volumes of hydrogen can produce large quantities of heavy water at an effective cost for use in heavy water reactors.

  2. Isotope Program Transportation | Department of Energy

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

    Isotope Program Transportation Isotope Program Transportation Isotope Program Transportation (894.11 KB) More Documents & Publications Nuclear Fuel Storage and Transportation Planning Project Overview Section 180(c) Ad Hoc Working Group DOE Office of Nuclear Energy

  3. Active helium target: Neutron scalar polarizability extraction via Compton scattering

    SciTech Connect (OSTI)

    Morris, Meg Hornidge, David; Annand, John; Strandberg, Bruno

    2015-12-31

    Precise measurement of the neutron scalar polarizabilities has been a lasting challenge because of the lack of a free-neutron target. Led by the University of Glasgow and the Mount Allison University groups of the A2 collaboration in Mainz, Germany, preparations have begun to test a recent theoretical model with an active helium target with the hope of determining these elusive quantities with small statistical, systematic, and model-dependent errors. Apparatus testing and background-event simulations have been carried out, with the full experiment projected to run in 2015. Once determined, these values can be applied to help understand quantum chromodynamics in the nonperturbative region.

  4. Dual-frequency glow discharges in atmospheric helium

    SciTech Connect (OSTI)

    Huang, Xiaojiang; Guo, Ying; Dai, Lu; Zhang, Jing; Shi, J. J.

    2015-10-15

    In this paper, the dual-frequency (DF) glow discharges in atmospheric helium were experimented by electrical and optical measurements in terms of current voltage characteristics and optical emission intensity. It is shown that the waveforms of applied voltages or discharge currents are the results of low frequency (LF) waveforms added to high frequency (HF) waveforms. The HF mainly influences discharge currents, and the LF mainly influences applied voltages. The gas temperatures of DF discharges are mainly affected by HF power rather than LF power.

  5. Helium nano-bubble evolution in aging metal tritides.

    SciTech Connect (OSTI)

    Cowgill, Donald F.

    2004-05-01

    A continuum-scale, evolutionary model of helium (He) nano-bubble nucleation, growth and He release for aging bulk metal tritides is presented which accounts for major features of the experimental database. Bubble nucleation, modeled as self-trapping of interstitially diffusing He atoms, is found to occur during the first few days following tritium introduction into the metal and is sensitive to the He diffusivity and pairing energy. An effective helium diffusivity of 0.3 x 10{sup -16} cm{sup 2}/s at 300 K is required to generate the average bubble density of 5x 1017 bubbles/cm3 observed by transmission electron microscopy (TEM). Early bubble growth by dislocation loop punching with a l/radius bubble pressure dependence produces good agreement with He atomic volumes and bubble pressures determined from swelling data, nuclear magnetic resonance (NMR) measurements, and hydride pressure-composition-temperature (PCT) shifts. The model predicts that later in life neighboring bubble interactions may first lower the loop punching pressure through cooperative stress effects, then raise the pressure by partial blocking of loops. It also accounts for the shape of the bubble spacing distribution obtained from NMR data. This distribution is found to remain fixed with age, justifying the separation of nucleation and growth phases, providing a sensitive test of the growth formulation, and indicating that further significant bubble nucleation does not occur throughout life. Helium generated within the escape depth of surfaces and surface-connected porosity produces the low-level early helium release. Accelerated or rapid release is modeled as inter-bubble fracture using an average ligament stress criterion. Good agreement is found between the predicted onset of fracture and the observed He-metal ratio (HeM) for rapid He release from bulk palladium tritide. An examination of how inter-bubble fracture varies over the bubble spacing distribution shows that the critical Hem will be

  6. Phonon coherence in isotopic silicon superlattices

    SciTech Connect (OSTI)

    Frieling, R.; Radek, M.; Eon, S.; Bracht, H.; Wolf, D. E.

    2014-09-29

    Recent experimental and theoretical investigations have confirmed that a reduction in thermal conductivity of silicon is achieved by isotopic silicon superlattices. In the present study, non-equilibrium molecular dynamics simulations are performed to identify the isotope doping and isotope layer ordering with minimum thermal conductivity. Furthermore, the impact of isotopic intermixing at the superlattice interfaces on phonon transport is investigated. Our results reveal that the coherence of phonons in isotopic Si superlattices is prevented if interfacial mixing of isotopes is considered.

  7. Method of separating boron isotopes

    DOE Patents [OSTI]

    Jensen, Reed J.; Thorne, James M.; Cluff, Coran L.; Hayes, John K.

    1984-01-01

    A method of boron isotope enrichment involving the isotope preferential photolysis of (2-chloroethenyl)dichloroborane as the feed material. The photolysis can readily be achieved with CO.sub.2 laser radiation and using fluences significantly below those required to dissociate BCl.sub.3.

  8. Method of separating boron isotopes

    DOE Patents [OSTI]

    Jensen, R.J.; Thorne, J.M.; Cluff, C.L.

    1981-01-23

    A method of boron isotope enrichment involving the isotope preferential photolysis of (2-chloroethenyl)-dichloroborane as the feed material. The photolysis can readily by achieved with CO/sub 2/ laser radiation and using fluences significantly below those required to dissociate BCl/sub 3/.

  9. Stable isotope research pool inventory

    SciTech Connect (OSTI)

    Not Available

    1980-12-01

    This report contains a listing of electromagnetically separated stable isotopes which are available for distribution within the United States for non-destructive research use from the Oak Ridge National Laboratory on a loan basis. This inventory includes all samples of stable isotopes in the Materials Research Collection and does not designate whether a sample is out on loan or in reprocessing.

  10. Heavy Isotopes Lead Materials Management Organization (LMMO)...

    Office of Scientific and Technical Information (OSTI)

    Heavy Isotopes Lead Materials Management Organization (LMMO) Update Citation Details In-Document Search Title: Heavy Isotopes Lead Materials Management Organization (LMMO) Update ...

  11. Isotopic Trends in Production of Superheavies

    SciTech Connect (OSTI)

    Antonenko, N.V.; Adamian, G.G.; Zubov, A.S.; Scheid, W.

    2005-11-21

    The isotopic trends are discussed for cold and hot fusion reactions leading to superheavies. The possibilities of production of new isotopes in incomplete fusion reactions are treated.

  12. Isotope separation by laser means

    DOE Patents [OSTI]

    Robinson, C. Paul; Jensen, Reed J.; Cotter, Theodore P.; Greiner, Norman R.; Boyer, Keith

    1982-06-15

    A process for separating isotopes by selective excitation of isotopic species of a volatile compound by tuned laser light. A highly cooled gas of the volatile compound is produced in which the isotopic shift is sharpened and defined. Before substantial condensation occurs, the cooled gas is irradiated with laser light precisely tuned to a desired wavelength to selectively excite a particular isotopic species in the cooled gas. The laser light may impart sufficient energy to the excited species to cause it to undergo photochemical reaction or even to photoionize. Alternatively, a two-photon irradiation may be applied to the cooled gas to induce photochemical reaction or photoionization. The process is particularly applicable to the separation of isotopes of uranium and plutonium.

  13. Ignition and extinction phenomena in helium micro hollow cathode discharges

    SciTech Connect (OSTI)

    Kulsreshath, M. K.; Schwaederle, L.; Dufour, T.; Lefaucheux, P.; Dussart, R.; Overzet, L. J.

    2013-12-28

    Micro hollow cathode discharges (MHCD) were produced using 250??m thick dielectric layer of alumina sandwiched between two nickel electrodes of 8??m thickness. A through cavity at the center of the chip was formed by laser drilling technique. MHCD with a diameter of few hundreds of micrometers allowed us to generate direct current discharges in helium at up to atmospheric pressure. A slowly varying ramped voltage generator was used to study the ignition and the extinction periods of the microdischarges. The analysis was performed by using electrical characterisation of the V-I behaviour and the measurement of He*({sup 3}S{sub 1}) metastable atoms density by tunable diode laser spectroscopy. At the ignition of the microdischarges, 2??s long current peak as high as 24?mA was observed, sometimes followed by low amplitude damped oscillations. At helium pressure above 400?Torr, an oscillatory behaviour of the discharge current was observed just before the extinction of the microdischarges. The same type of instability in the extinction period at high pressure also appeared on the density of He*({sup 3}S{sub 1}) metastable atoms, but delayed by a few ?s relative to the current oscillations. Metastable atoms thus cannot be at the origin of the generation of the observed instabilities.

  14. Gettering of Hydrogen and Methane from a Helium Gas Mixture

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

    Cardenas, Rosa E.; Stewart, Kenneth D.; Cowgill, Donald F.

    2014-10-21

    In our study, the authors developed an approach for accurately quantifying the helium content in a gas mixture also containing hydrogen and methane using commercially available getters. The authors performed a systematic study to examine how both H2 and CH4 can be removed simultaneously from the mixture using two SAES St 172® getters operating at different temperatures. The remaining He within the gas mixture can then be measured directly using a capacitance manometer. Moreover, the optimum combination involved operating one getter at 650°C to decompose the methane, and the second at 110°C to remove the hydrogen. Finally, this approach eliminatedmore » the need to reactivate the getters between measurements, thereby enabling multiple measurements to be made within a short time interval, with accuracy better than 1%. The authors anticipate that such an approach will be particularly useful for quantifying the He-3 in mixtures that include tritium, tritiated methane, and helium-3. The presence of tritiated methane, generated by tritium activity, often complicates such measurements.« less

  15. Gettering of Hydrogen and Methane from a Helium Gas Mixture

    SciTech Connect (OSTI)

    Cardenas, Rosa E.; Stewart, Kenneth D.; Cowgill, Donald F.

    2014-10-21

    In our study, the authors developed an approach for accurately quantifying the helium content in a gas mixture also containing hydrogen and methane using commercially available getters. The authors performed a systematic study to examine how both H2 and CH4 can be removed simultaneously from the mixture using two SAES St 172® getters operating at different temperatures. The remaining He within the gas mixture can then be measured directly using a capacitance manometer. Moreover, the optimum combination involved operating one getter at 650°C to decompose the methane, and the second at 110°C to remove the hydrogen. Finally, this approach eliminated the need to reactivate the getters between measurements, thereby enabling multiple measurements to be made within a short time interval, with accuracy better than 1%. The authors anticipate that such an approach will be particularly useful for quantifying the He-3 in mixtures that include tritium, tritiated methane, and helium-3. The presence of tritiated methane, generated by tritium activity, often complicates such measurements.

  16. Gettering of hydrogen and methane from a helium gas mixture

    SciTech Connect (OSTI)

    Crdenas, Rosa Elia; Stewart, Kenneth D.; Cowgill, Donald F.

    2014-11-01

    In this study, the authors developed an approach for accurately quantifying the helium content in a gas mixture also containing hydrogen and methane using commercially available getters. The authors performed a systematic study to examine how both H{sub 2} and CH{sub 4} can be removed simultaneously from the mixture using two SAES St 172{sup } getters operating at different temperatures. The remaining He within the gas mixture can then be measured directly using a capacitance manometer. The optimum combination involved operating one getter at 650?C to decompose the methane, and the second at 110?C to remove the hydrogen. This approach eliminated the need to reactivate the getters between measurements, thereby enabling multiple measurements to be made within a short time interval, with accuracy better than 1%. The authors anticipate that such an approach will be particularly useful for quantifying the He-3 in mixtures that include tritium, tritiated methane, and helium-3. The presence of tritiated methane, generated by tritium activity, often complicates such measurements.

  17. Helium Nano-Bubble Evolution in Aging Metal Tritides

    SciTech Connect (OSTI)

    Cowgill, Donald F.

    2005-07-15

    A continuum-scale, evolutionary model of bubble nucleation, growth and He release for aging metal tritides is described which accounts for major features of the tritide database. Bubble nucleation, modeled as self-trapping of interstitially diffusing He atoms, occurs during the first few days following tritium introduction into the metal. Bubble growth by dislocation loop punching yields good agreement between He atomic volumes and bubble pressures determined from bulk swelling and {sup 3}He NMR data. The bubble spacing distribution determined from NMR is shown to remain fixed with age, justifying the separation of nucleation and growth phases and providing a sensitive test of the growth formulation. Late in life, bubble interactions are proposed to produce cooperative stress effects, which lower the bubble pressure. Helium generated near surfaces and surface-connected porosity accounts for the low-level early helium release. Use of an average ligament stress criterion predicts an onset of inter-bubble fracture in good agreement with the He/Metal ratio observed for rapid He release. From the model, it is concluded that He retention can be controlled through control of bubble nucleation.

  18. Partial cross sections of helium satellites at medium photon energies

    SciTech Connect (OSTI)

    Wehlitz, R.; Sellin, I.A.; Hemmers, O.

    1997-04-01

    Still of current interest is the important role of single ionization with excitation compared to single ionization alone. The coupling between the electrons and the incoming photon is a single-particle operator. Thus, an excitation in addition to an ionization, leading to a so-called satellite line in a photoelectron spectrum, is entirely due to electron-electron interaction and probes the electron correlation in the ground and final state. Therefore the authors have undertaken the study of the intensity of helium satellites He{sup +}nl (n = 2 - 6) relative to the main photoline (n = 1) as a function of photon energy at photon energies well above threshold up to 900 eV. From these results they could calculate the partial cross-sections of the helium satellites. In order to test the consistency of their satellite-to-1s ratios with published double-to-single photoionization ratios, the authors calculated the double-to-single photoionization ratio from their measured ratios using the theoretical energy-distribution curves of Chang and Poe and Le Rouzo and Dal Cappello which proved to be valid for photon energies below 120 eV. These calculated double-to-single ionization ratios agree fairly well with recent ion measurements. In the lower photon energy range the authors ratios agree better with the ratios of Doerner et al. while for higher photon energies the agreement is better with the values of Levin et al.

  19. Container for hydrogen isotopes

    DOE Patents [OSTI]

    Solomon, David E.

    1977-01-01

    A container for the storage, shipping and dispensing of hydrogen isotopes such as hydrogen, deuterium, tritium, or mixtures of the same which has compactness, which is safe against fracture or accident, and which is reusable. The container consists of an outer housing with suitable inlet and outlet openings and electrical feed elements, the housing containing an activated sorber material in the form, for example, of titanium sponge or an activated zirconium aluminate cartridge. The gas to be stored is introduced into the chamber under conditions of heat and vacuum and will be retained in the sorber material. Subsequently, it may be released by heating the unit to drive off the stored gas at desired rates.

  20. Fundamental and applied studies of helium ingrowth and aging in plutonium

    SciTech Connect (OSTI)

    Stevens, M.F.; Zocco, T.; Albers, R.; Becker, J.D.; Walter, K.; Cort, B.; Paisley, D.; Nastasi, M.

    1998-12-31

    This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The purpose of this project was to develop new capabilities to assess the nucleation and growth of helium-associated defects in aged plutonium metal. This effort involved both fundamental and applied models to assist in predicting the transport and kinetics of helium in the metal lattice as well as ab initio calculations of the disposition of gallium in the fcc plutonium lattice and its resulting effects on phase stability. Experimentally this project aimed to establish experimental capabilities crucial to the prediction of helium effects in metals, such as transmission electron microscopy, thermal helium effusion, and the development of a laser-driven mini-flyer for understanding the role of helium and associated defects on shock response of plutonium surrogates.

  1. Laser separation of medical isotopes

    SciTech Connect (OSTI)

    Eerkens, J.W.; Puglishi, D.A.; Miller, W.H.

    1996-12-31

    There is an increasing demand for different separated isotopes as feed material for reactor and cyclotron-produced radioisotopes used by a fast-growing radiopharmaceutical industry. One new technology that may meet future demands for medical isotopes is molecular laser isotope separation (MLIS). This method was investigated for the enrichment of uranium in the 1970`s and 1980s by Los Alamos National Laboratory, Isotope Technologies, and others around the world. While South Africa and Japan have continued the development of MLIS for uranium and are testing pilot units, around 1985 the United States dropped the LANL MLIS program in favor of AVLIS (atomic vapor LIS), which uses electron-beam-heated uranium metal vapor. AVLIS appears difficult and expensive to apply to most isotopes of medical interest, however, whereas MLIS technology, which is based on cooled hexafluorides or other gaseous molecules, can be adapted more readily. The attraction of MLIS for radiopharmaceutical firms is that it allows them to operate their own dedicated separators for small-quantity productions of critical medical isotopes, rather than having to depend on large enrichment complexes run by governments, which are only optimal for large-quantity productions. At the University of Missouri, the authors are investigating LIS of molybdenum isotopes using MoF{sub 6}, which behaves in a way similar to UF{sub 6}, studied in the past.

  2. Stable isotope research pool inventory

    SciTech Connect (OSTI)

    Not Available

    1981-01-01

    This report contains a listing of electromagnetically separated stable isotopes which are available for distribution within the United States for non-destructive research use from the Oak Ridge National Laboratory on a loan basis. This inventory includes all samples of stable isotopes in the Materials Research Collection and does not designate whether a sample is out on loan or in reprocessing. For some of the high abundance naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56.

  3. Stable isotope research pool inventory

    SciTech Connect (OSTI)

    Not Available

    1983-03-01

    This report contains a listing of electromagnetically separated stable isotopes which are available for distribution within the United States for non-destructive research use from the Oak Ridge National Laboratory on a loan basis. This inventory includes all samples of stable isotopes in the Materials Research Collection and does not designate whether a sample is out on loan or in reprocessing. For some of the high abundance naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56.

  4. Compelling Research Opportunities using Isotopes

    SciTech Connect (OSTI)

    2009-04-23

    Isotopes are vital to the science and technology base of the US economy. Isotopes, both stable and radioactive, are essential tools in the growing science, technology, engineering, and health enterprises of the 21st century. The scientific discoveries and associated advances made as a result of the availability of isotopes today span widely from medicine to biology, physics, chemistry, and a broad range of applications in environmental and material sciences. Isotope issues have become crucial aspects of homeland security. Isotopes are utilized in new resource development, in energy from bio-fuels, petrochemical and nuclear fuels, in drug discovery, health care therapies and diagnostics, in nutrition, in agriculture, and in many other areas. The development and production of isotope products unavailable or difficult to get commercially have been most recently the responsibility of the Department of Energy's Nuclear Energy program. The President's FY09 Budget request proposed the transfer of the Isotope Production program to the Department of Energy's Office of Science in Nuclear Physics and to rename it the National Isotope Production and Application program (NIPA). The transfer has now taken place with the signing of the 2009 appropriations bill. In preparation for this, the Nuclear Science Advisory Committee (NSAC) was requested to establish a standing subcommittee, the NSAC Isotope Subcommittee (NSACI), to advise the DOE Office of Nuclear Physics. The request came in the form of two charges: one, on setting research priorities in the short term for the most compelling opportunities from the vast array of disciplines that develop and use isotopes and two, on making a long term strategic plan for the NIPA program. This is the final report to address charge 1. NSACI membership is comprised of experts from the diverse research communities, industry, production, and homeland security. NSACI discussed research opportunities divided into three areas: (1) medicine

  5. Apparatus and process for separating hydrogen isotopes

    DOE Patents [OSTI]

    Heung, Leung K; Sessions, Henry T; Xiao, Xin

    2013-06-25

    The apparatus and process for separating hydrogen isotopes is provided using dual columns, each column having an opposite hydrogen isotopic effect such that when a hydrogen isotope mixture feedstock is cycled between the two respective columns, two different hydrogen isotopes are separated from the feedstock.

  6. Method for laser induced isotope enrichment

    DOE Patents [OSTI]

    Pronko, Peter P.; Vanrompay, Paul A.; Zhang, Zhiyu

    2004-09-07

    Methods for separating isotopes or chemical species of an element and causing enrichment of a desired isotope or chemical species of an element utilizing laser ablation plasmas to modify or fabricate a material containing such isotopes or chemical species are provided. This invention may be used for a wide variety of materials which contain elements having different isotopes or chemical species.

  7. Raman scattering method and apparatus for measuring isotope ratios and isotopic abundances

    DOE Patents [OSTI]

    Harney, Robert C.; Bloom, Stewart D.

    1978-01-01

    Raman scattering is used to measure isotope ratios and/or isotopic abundances. A beam of quasi-monochromatic photons is directed onto the sample to be analyzed, and the resulting Raman-scattered photons are detected and counted for each isotopic species of interest. These photon counts are treated mathematically to yield the desired isotope ratios or isotopic abundances.

  8. Physics with isotopically controlled semiconductors

    SciTech Connect (OSTI)

    Haller, E. E.

    2010-07-15

    This paper is based on a tutorial presentation at the International Conference on Defects in Semiconductors (ICDS-25) held in Saint Petersburg, Russia in July 2009. The tutorial focused on a review of recent research involving isotopically controlled semiconductors. Studies with isotopically enriched semiconductor structures experienced a dramatic expansion at the end of the Cold War when significant quantities of enriched isotopes of elements forming semiconductors became available for worldwide collaborations. Isotopes of an element differ in nuclear mass, may have different nuclear spins and undergo different nuclear reactions. Among the latter, the capture of thermal neutrons which can lead to neutron transmutation doping, is the most prominent effect for semiconductors. Experimental and theoretical research exploiting the differences in all the properties has been conducted and will be illustrated with selected examples.

  9. Stable isotope research pool inventory

    SciTech Connect (OSTI)

    Not Available

    1985-02-01

    This report contains a listing of electromagnetically separated stable isotopes which are available at the Oak Ridge National Laboratory for distribution for non-destructive research use on a loan basis. This inventory includes all samples of stable isotopes in the Research Materials Collection and does not designate whether a sample is out on loan or is in reprocessing. For some of the high abundance naturally occurring isotopes, larger amounts can be made available; for example, /sup 40/Ca and /sup 56/Fe. All request for the loan of samples should be submitted with a summary of the purpose of the loan to: Isotope Distribution Office, Oak Ridge National Laboratory, P.O. Box X, Oak Ridge, Tennessee 37831. Requests from non-DOE contractors and from foreign institutions require DOE approval.

  10. Friction-Induced Fluid Heating in Nanoscale Helium Flows

    SciTech Connect (OSTI)

    Li Zhigang [Department of Mechanical Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)

    2010-05-21

    We investigate the mechanism of friction-induced fluid heating in nanoconfinements. Molecular dynamics simulations are used to study the temperature variations of liquid helium in nanoscale Poiseuille flows. It is found that the fluid heating is dominated by different sources of friction as the external driving force is changed. For small external force, the fluid heating is mainly caused by the internal viscous friction in the fluid. When the external force is large and causes fluid slip at the surfaces of channel walls, the friction at the fluid-solid interface dominates over the internal friction in the fluid and is the major contribution to fluid heating. An asymmetric temperature gradient in the fluid is developed in the case of nonidentical walls and the general temperature gradient may change sign as the dominant heating factor changes from internal to interfacial friction with increasing external force.

  11. Effect of helium on the electronic structure of palladium tritide

    SciTech Connect (OSTI)

    Gupta, R.P.; Gupta, M.

    1998-12-31

    Tritium is usually stored in the form of a metal tritide since it is safe to handle in this form, easily recoverable, and further large quantities of tritium can be stored. However, since tritium is radioactive it decays into {sup 3}He and an electron. Helium recoil energy in this reaction is very small, and not enough to create defects. The authors have performed ab-initio electronic structure calculations that show that in PdT, a considerable amount of {sup 3}He can be accommodated at the octahedral interstitial sites where it is produced. Their calculations also show that the presence of {sup 3}He results in an overall enhancement in the strength of the metal-tritium bonding that leads to the lowering of the plateau pressure. They also find that there is a weakening of the metal-metal bonds due to the repulsive interaction with {sup 3}He.

  12. Options for Cryogenic Load Cooling with Forced Flow Helium Circulation

    SciTech Connect (OSTI)

    Peter Knudsen, Venkatarao Ganni, Roberto Than

    2012-06-01

    Cryogenic pumps designed to circulate super-critical helium are commonly deemed necessary in many super-conducting magnet and other cooling applications. Acknowledging that these pumps are often located at the coldest temperature levels, their use introduces risks associated with the reliability of additional rotating machinery and an additional load on the refrigeration system. However, as it has been successfully demonstrated, this objective can be accomplished without using these pumps by the refrigeration system, resulting in lower system input power and improved reliability to the overall cryogenic system operations. In this paper we examine some trade-offs between using these pumps vs. using the refrigeration system directly with examples of processes that have used these concepts successfully and eliminated using such pumps

  13. Symmetric And Non-Symmetric Muonic Helium Atoms Studies

    SciTech Connect (OSTI)

    Mohammadi, S.

    2011-10-28

    The ground state hyperfine structure and other properties are calculated for muonic helium atoms ({sup 3}He{sup +2}{mu}{sup -}e{sup -} or {sup 4}He{sup +2}{mu}{sup -}e{sup -}) with the use of some local properties of the wave functions in the domains where two particles are close to each other or far away. Simple wave functions incorporating these properties with one variational parameter is developed. The calculated values for hyperfine structure, energy and average interparticle distances in ground state are compared with the correlation function hyper-spherical harmonic method and multibox variational approach. The obtained results are very close to the values calculated by mentioned methods, giving strong indications that the proposed wave functions provide relatively accurate values.

  14. Evaluation of the Gas Turbine Modular Helium Reactor

    SciTech Connect (OSTI)

    Not Available

    1994-02-01

    Recent advances in gas-turbine and heat exchanger technology have enhanced the potential for a Modular Helium Reactor (MHR) incorporating a direct gas turbine (Brayton) cycle for power conversion. The resulting Gas Turbine Modular Helium Reactor (GT-MHR) power plant combines the high temperature capabilities of the MHR with the efficiency and reliability of modern gas turbines. While the passive safety features of the steam cycle MHR (SC-MHR) are retained, generation efficiencies are projected to be in the range of 48% and steam power conversion systems, with their attendant complexities, are eliminated. Power costs are projected to be reduced by about 20%, relative to the SC-MHR or coal. This report documents the second, and final, phase of a two-part evaluation that concluded with a unanimous recommendation that the direct cycle (DC) variant of the GT-MHR be established as the commercial objective of the US Gas-Cooled Reactor Program. This recommendation has been endorsed by industrial and utility participants and accepted by the US Department of Energy (DOE). The Phase II effort, documented herein, concluded that the DC GT-MHR offers substantial technical and economic advantages over both the IDC and SC systems. Both the DC and IDC were found to offer safety advantages, relative to the SC, due to elimination of the potential for water ingress during power operations. This is the dominant consequence event for the SC. The IDC was judged to require somewhat less development than the direct cycle, while the SC, which has the greatest technology base, incurs the least development cost and risk. While the technical and licensing requirements for the DC were more demanding, they were judged to be incremental and feasible. Moreover, the DC offers significant performance and cost improvements over the other two concepts. Overall, the latter were found to justify the additional development needs.

  15. Superconducting cable cooling system by helium gas at two pressures

    DOE Patents [OSTI]

    Dean, John W.

    1977-01-01

    Thermally contacting, oppositely streaming, cryogenic fluid streams in the same enclosure in a closed cycle that changes the fluid from a cool high pressure helium gas to a cooler reduced pressure helium gas in an expander so as to be at different temperature ranges and pressures respectively in go and return legs that are in thermal contact with each other and in thermal contact with a longitudinally extending superconducting transmission line enclosed in the same cable enclosure that insulates the line from the ambient at a temperature T.sub.1. By first circulating the fluid from a refrigerator at one end of the line as a cool gas at a temperature range T.sub.2 to T.sub.3 in the go leg, then circulating the gas through an expander at the other end of the line where the gas becomes a cooler gas at a reduced pressure and at a reduced temperature T.sub.4 and finally by circulating the cooler gas back again to the refrigerator in a return leg at a temperature range T.sub.4 to T.sub.5, while in thermal contact with the gas in the go leg, and in the same enclosure therewith for compression into a higher pressure gas at T.sub.2 in a closed cycle, where T.sub.2 >T.sub.3 and T.sub.5 >T.sub.4, the fluid leaves the enclosure in the go leg as a gas at its coldest point in the go leg, and the temperature distribution is such that the line temperature decreases along its length from the refrigerator due to the cooling from the gas in the return leg.

  16. Novel hybrid isotope separation scheme and apparatus

    DOE Patents [OSTI]

    Maya, Jakob

    1991-01-01

    A method of yielding selectively a desired enrichment in a specific isotope including the steps of inputting into a spinning chamber a gas from which the specific isotope is to be isolated, radiating the gas with frequencies characteristic of the absorption of a particular isotope of the atomic or molecular gas, thereby inducing a photoionization reaction of the desired isotope, and collecting the specific isotope ion by suitable ion collection means.

  17. Novel hybrid isotope separation scheme and apparatus

    DOE Patents [OSTI]

    Maya, J.

    1991-06-18

    A method is described for yielding selectively a desired enrichment in a specific isotope including the steps of inputting into a spinning chamber a gas from which the specific isotope is to be isolated, radiating the gas with frequencies characteristic of the absorption of a particular isotope of the atomic or molecular gas, thereby inducing a photoionization reaction of the desired isotope, and collecting the specific isotope ion by suitable ion collection means. 3 figures.

  18. Isotope separation apparatus and method

    DOE Patents [OSTI]

    Feldman, Barry J.

    1985-01-01

    The invention relates to an improved method and apparatus for laser isotope separation by photodeflection. A molecular beam comprising at least two isotopes to be separated intersects, preferably substantially perpendicular to one broad side of the molecular beam, with a laser beam traveling in a first direction. The laser beam is reflected back through the molecular beam, preferably in a second direction essentially opposite to the first direction. Because the molecules in the beam occupy various degenerate energy levels, if the laser beam comprises chirped pulses comprising selected wavelengths, the laser beam will very efficiently excite substantially all unexcited molecules and will cause stimulated emission of substantially all excited molecules of a selected one of the isotopes in the beam which such pulses encounter. Excitation caused by first direction chirped pulses moves molecules of the isotope excited thereby in the first direction. Stimulated emission of excited molecules of the isotope is brought about by returning chirped pulses traveling in the second direction. Stimulated emission moves emitting molecules in a direction opposite to the photon emitted. Because emitted photons travel in the second direction, emitting molecules move in the first direction. Substantial molecular movement of essentially all the molecules containing the one isotope is accomplished by a large number of chirped pulse-molecule interactions. A beam corer collects the molecules in the resulting enriched divergent portions of the beam.

  19. Facile time-of-flight methods for characterizing pulsed superfluid helium droplet beams

    SciTech Connect (OSTI)

    He, Yunteng; Zhang, Jie; Li, Yang; Freund, William M.; Kong, Wei

    2015-08-15

    We present two facile time-of-flight (TOF) methods of detecting superfluid helium droplets and droplets with neutral dopants. Without an electron gun and with only a heated filament and pulsed electrodes, the electron impact ionization TOF mass spectrometer can resolve ionized helium clusters such as He{sub 2}{sup +} and He{sub 4}{sup +}, which are signatures of superfluid helium droplets. Without ionizing any helium atoms, multiphoton non-resonant laser ionization of CCl{sub 4} doped in superfluid helium droplets at 266 nm generates complex cluster ions of dopant fragments with helium atoms, including (He){sub n}C{sup +}, (He){sub n}Cl{sup +}, and (He){sub n}CCl{sup +}. Using both methods, we have characterized our cryogenic pulsed valve—the Even-Lavie valve. We have observed a primary pulse with larger helium droplets traveling at a slower speed and a rebound pulse with smaller droplets at a faster speed. In addition, the pickup efficiency of dopant is higher for the primary pulse when the nozzle temperature is higher than 13 K, and the total time duration of the doped droplet pulse is only on the order of 20 μs. These results stress the importance of fast and easy characterization of the droplet beam for sensitive measurements such as electron diffraction of doped droplets.

  20. Preparation and thermal desorption properties of dc sputtered zirconium-hydrogen-helium thin films

    SciTech Connect (OSTI)

    Wei, Y. C.; Shi, L. Q.; Zhang, L.; He, Z. J.; Zhang, B.; Wang, L. B.

    2008-11-15

    We developed a new approach for preparing hydrogen and helium co-containing zirconium films (Zr-H-He) to simulate aging metal tritides. We also studied the effect of hydrogen on helium behavior, in which we applied direct current magnetron sputtering in a mixture of working gases (helium, argon, and hydrogen). The amount and depth profile of helium and hydrogen trapped in the films were determined using the elastic recoil detection analysis. The microstructure and surface morphology of the Zr-H-He films were studied by x-ray diffraction, transmission electron microscopy, and atomic force microscopy. To investigate the effect of hydrogen on the thermal release behavior of helium in the Zr film, thermal desorption spectrometry (TDS) was used, which revealed a similar desorption behavior to aged tritides. TDS experiments showed that the spectra were constituted by low-temperature peaks around 300 deg. C and high temperature peaks above 750 deg. C. Furthermore, the solid-phase {alpha} to {delta} transformation changed the shapes of the high-temperature peaks related to microstates of helium bubbles and caused the peak with a massive helium release shift toward lower temperature obviously.

  1. Cavity morphology in a Ni based superalloy under heavy ion irradiation with hot pre-injected helium. II

    SciTech Connect (OSTI)

    Zhang, He; Yao, Zhongwen, E-mail: yaoz@me.queensu.ca; Daymond, Mark R. [Department of Mechanical and Materials Engineering, Queen's University Kingston, Ontario K7L 3N6 (Canada); Kirk, Marquis A. [Material Science Division, Argonne National Laboratory Argonne, Illinois 60439 (United States)

    2014-03-14

    In the current investigation, TEM in-situ heavy ion (1?MeV Kr{sup 2+}) irradiation with helium pre-injected at elevated temperature (400?C) was conducted to simulate in-reactor neutron irradiation induced damage in CANDU spacer material Inconel X-750, in an effort to understand the effects of helium on irradiation induced cavity microstructures. Three different quantities of helium, 400 appm, 1000 appm, and 5000 appm, were pre-injected directly into TEM foils at 400?C. The samples containing helium were then irradiated in-situ with 1?MeV Kr{sup 2+} at 400?C to a final dose of 5.4 dpa (displacement per atom). Cavities were formed from the helium injection solely and the cavity density and size increased with increasing helium dosage. In contrast to previous heavy ion irradiations with cold pre-injected helium, heterogeneous nucleation of cavities was observed. During the ensuing heavy ion irradiation, dynamical observation showed noticeable size increase in cavities which nucleated close to the grain boundaries. A bubble-void transformation was observed after Kr{sup 2+} irradiation to high dose (5.4?dpa) in samples containing 1000 appm and 5000 appm helium. Cavity distribution was found to be consistent with in-reactor neutron irradiation induced cavity microstructures. This implies that the distribution of helium is greatly dependent on the injection temperature, and helium pre-injection at high temperature is preferred for simulating the migration of the transmutation produced helium.

  2. Remote reactor repair: GTA (gas tungsten Arc) weld cracking caused by entrapped helium

    SciTech Connect (OSTI)

    Kanne, W.R. Jr.

    1988-01-01

    A repair patch was welded to the wall of a nuclear reactor tank using remotely controlled thirty-foot long robot arms. Further repair was halted when gas tungsten arc (GTA) welds joining type 304L stainless steel patches to the 304 stainless steel wall developed toe cracks in the heat-affected zone (HAZ). The role of helium in cracking was investigated using material with entrapped helium from tritium decay. As a result of this investigation, and of an extensive array of diagnostic tests performed on reactor tank wall material, helium embrittlement was shown to be the cause of the toe cracks.

  3. Effects of helium content of microstructural development in Type 316 stainless steel under neutron irradiation

    SciTech Connect (OSTI)

    Maziasz, P.J.

    1985-11-01

    This work investigated the sensitivity of microstructural evolution, particularly precipitate development, to increased helium content during thermal aging and during neutron irradiation. Helium (110 at. ppM) was cold preinjected into solution annealed (SA) DO-heat type 316 stainess steel (316) via cyclotron irradiation. These specimens were then exposed side by side with uninjected samples. Continuous helium generation was increased considerably relative to EBR-II irradiation by irradiation in HFIR. Data were obtained from quantitative analytical electron microscopy (AEM) in thin foils and on extraction replicas. 480 refs., 86 figs., 19 tabs.

  4. Helium bubble evolution in a Zr–Sn–Nb–Fe–Cr alloy during post-annealing: An in-situ investigation

    SciTech Connect (OSTI)

    Shen, H.H.; Peng, S.M.; Chen, B.; Naab, F.N.; Sun, G.A.; Zhou, W.; Xiang, X.; Sun, K.; Zu, X.T.

    2015-09-15

    The formation of helium bubbles is considered to be detrimental to the mechanical performance of the nuclear materials. The growth behaviors of helium bubbles in a helium ion implanted Zr–Sn–Nb–Fe–Cr alloy with respect to the helium fluence and subsequently annealing procedure were investigated by in-situ transmission electron microscopy. In the as-implanted sample, the measured size distributions of the helium bubbles are consistent with the simulated helium concentrations. Moreover, the mean size of the helium bubbles increases with the increase of the irradiation temperatures and the helium fluence. The in-situ heating study performed in a transmission electron microscope indicates that the mean size of the helium bubbles increase slowly below 923 K and dramatically above 923 K. The coarsening mechanism of the helium bubbles in the alloy is suggested based on the study. - Highlights: • Helium bubble growth in zirconium with annealing was in-situ investigated in TEM. • The mean helium bubble size increase with helium fluence and annealing temperature. • Helium bubble size distribution is same as that of helium concentration by SRIM. • Mean bubble size increases slowly and quickly with temperature below and above 923 K. • The growth mechanism of the helium bubbles in Zr alloy has been discussed.

  5. Atomic line emission analyzer for hydrogen isotopes (Patent)...

    Office of Scientific and Technical Information (OSTI)

    Atomic line emission analyzer for hydrogen isotopes Title: Atomic line emission analyzer for hydrogen isotopes Apparatus for isotopic analysis of hydrogen comprises a low pressure ...

  6. Department of Energy's Isotope Development and Production for...

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

    ... The Isotope Program prices isotopes sold for medical and industrial applications to recover full cost. Isotopes sold for research and development are priced to recover direct costs ...

  7. Isotope production facility produces cancer-fighting actinium

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

    Cancer therapy gets a boost from new isotope Isotope production facility produces cancer-fighting actinium A new medical isotope project shows promise for rapidly producing major ...

  8. Isotope separation by photochromatography (Patent) | SciTech...

    Office of Scientific and Technical Information (OSTI)

    Patent: Isotope separation by photochromatography Citation Details In-Document Search Title: Isotope separation by photochromatography An isotope separation method which comprises ...

  9. Isotope separation apparatus and method

    DOE Patents [OSTI]

    Cotter, Theodore P.

    1982-12-28

    The invention relates to a method and apparatus for laser isotope separation by photodeflection. A molecular beam comprising at least two isotopes to be separated intersects, preferable substantially perpendicular to one broad side of the molecular beam, with a laser beam traveling in a first direction. The laser beam is reflected back through the molecular beam, preferably in a second direction essentially opposite to the first direction. The laser beam comprises .pi.-pulses of a selected wavelength which excite unexcited molecules, or cause stimulated emission of excited molecules of one of the isotopes. Excitation caused by first direction .pi.-pulses moves molecules of the isotope excited thereby in the first direction. Stimulated emission of excited molecules of the isotope is brought about by returning .pi.-pulses traveling in the second direction. Stimulated emission moves emitting molecules in a direction opposite to the photon emitted. Because emitted photons travel in the second direction, emitting molecules move in the first direction. Substantial molecular movement is accomplished by a large number of .pi.-pulse-molecule interactions. A beam corer collects the molecules in the resulting enriched divergent portions of the beam.

  10. Note: Control of liquid helium supply to cryopanels of Kolkata superconducting cyclotron

    SciTech Connect (OSTI)

    Bhattacharyya, T. K. Pal, G.

    2015-02-15

    The Kolkata superconducting cyclotron utilises liquid helium to cool the main magnet niobium-titanium (NbTi) coil and the cryopanels. Three liquid helium cooled cryopanels, placed inside the dees of the radio-frequency system, maintain the high vacuum in the acceleration region of the superconducting cyclotron. The small cryostat placed inside the cryogenic distribution manifold located at the basement of the superconducting cyclotron building supplies liquid helium in parallel branches to three cold heads, used for cooling their associated cryopanels. The level in the cryostat has to be maintained at an optimum value to ensure uninterrupted flow of liquid helium to these three cold heads. This paper describes the transfer function of the overall system, its tuning parameters, and discusses the actual control of cryostat level by using these parameters.

  11. Research and development of a helium-4 based solar neutrino detector

    SciTech Connect (OSTI)

    Lanou, R.E.; Maris, H.J.; Seidel, G.M.

    1990-12-01

    We report on work accomplished in the first 30 months of a research and development program to investigate the feasibility of a new technique to detect solar neutrinos in superfluid helium. Accomplishments include the successful completion of design, construction and operation of the entire cryogenic, mechanical and electronic apparatus. During the last several months we have begun a series of experiments in superfluid helium to test the method. Experimental results include the first observation of the combined physical processes essential to the detection technique: ballistic roton generation by energetic charged particles, quantum evaporation of helium at a free surface and bolometric detection of the evaporated helium by physisorption on a cold silicon wafer. Additional results are also presented.

  12. Helium release rates and ODH calculations from RHIC magnet cooling line failure

    SciTech Connect (OSTI)

    Liaw, C.J.; Than, Y.; Tuozzolo, J.

    2011-03-28

    A catastrophic failure of the magnet cooling lines, similar to the LHC superconducting bus failure incident, could discharge cold helium into the RHIC tunnel and cause an Oxygen Deficiency Hazard (ODH) problem. A SINDA/FLUINT{reg_sign} model, which simulated the 4.5K/4 atm helium flowing through the magnet cooling system distribution lines, then through a line break into the insulating vacuum volumes and discharging via the reliefs into the RHIC tunnel, had been developed. Arc flash energy deposition and heat load from the ambient temperature cryostat surfaces are included in the simulations. Three typical areas: the sextant arc, the Triplet/DX/D0 magnets, and the injection area, had been analyzed. Results, including helium discharge rates, helium inventory loss, and the resulting oxygen concentration in the RHIC tunnel area, are reported. Good agreement had been achieved when comparing the simulation results, a RHIC sector depressurization test measurement, and some simple analytical calculations.

  13. Evaluation of helium impurity impacts on Spent Nuclear Fuel project processes (OCRWM)

    SciTech Connect (OSTI)

    SHERRELL, D.L.

    1999-09-21

    This document identifies the types and quantities of impurities that may be present within helium that is introduced into multi-canister overpacks (MCO)s by various SNF Project facilities, including, but not limited to the Cold Vacuum Drying (CVD) Facility (CVDF). It then evaluates possible impacts of worst case impurity inventories on MCO drying, transportation, and storage processes. Based on the evaluation results, this document: (1) concludes that the SNF Project helium procurement specification can be a factor-of-ten less restrictive than a typical vendor's standard offering (99.96% pure versus the vendor's 99.997% pure standard offering); (2) concludes that the CVDF's current 99.5% purity requirement is adequate to control the quality of the helium that is delivered to the MCO by the plant's helium distribution system; and (3) recommends specific impurity limits for both of the above cases.

  14. Radon and helium in soil gases in the Phlegraean Fields, central Italy

    SciTech Connect (OSTI)

    Lombardi, S. ); Reimer, G.M. )

    1990-05-01

    The distribution and migration of radon and helium soil-gas concentrations in the Phlegraean Fields, Italy, are controlled by the tectonic features of the area. Radon is supplied from surficial sources and helium has both surficial and deep origins. There is no direct correlation between the two noble gases on a point-to-point basis but the areal distribution of both gases is similar, suggesting that the distribution is controlled primarily by fractures and movement of geothermal fluids.

  15. Isotope specific arbitrary material sorter

    DOE Patents [OSTI]

    Barty, Christopher P.J.

    2015-12-08

    A laser-based mono-energetic gamma-ray source is used to provide a rapid and unique, isotope specific method for sorting materials. The objects to be sorted are passed on a conveyor in front of a MEGa-ray beam which has been tuned to the nuclear resonance fluorescence transition of the desired material. As the material containing the desired isotope traverses the beam, a reduction in the transmitted MEGa-ray beam occurs. Alternately, the laser-based mono-energetic gamma-ray source is used to provide non-destructive and non-intrusive, quantitative determination of the absolute amount of a specific isotope contained within pipe as part of a moving fluid or quasi-fluid material stream.

  16. Stable isotope research pool inventory

    SciTech Connect (OSTI)

    Not Available

    1986-08-01

    This report contains a listing of electromagnetically separated stable isotopes which are available at the Oak Ridge National Laboratory for distribution for nondestructive research use on a loan basis. This inventory includes all samples of stable isotopes in the Research Materials Collection and does not designate whether a sample is out on loan or is in reprocessing. For some of the high-abundance, naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56. All requests for the loan of samples should be submitted with a summary of the purpose of the loan to: Iotope Distribution Office, Oak Ridge National Laboratory, P.O. Box X, Oak Ridge, Tennessee 37831. Requests from non-DOE contractors and from foreign institutions require DOE approval.

  17. Design, fabrication, and testing of a getter-based atmosphere purification and waste treatment system for a nitrogen-hydrogen-helium glovebox

    SciTech Connect (OSTI)

    Bibeault, M. L.; Paglieri, S. N.; Tuggle, D. G.; Wermer, J. R.; Nobile Jr, A.

    2008-07-15

    A system containing a combination of getters (Zr-Mn-Fe, SAES St909; and Zr{sub 2}Fe, SAES St198) was used to process the nitrogen-hydrogen-helium atmosphere in a glovebox used for handling metal tritide samples. During routine operations, the glovebox atmosphere is recirculated and hydrogenous impurities (i.e. CQ{sub 4}, Q{sub 2}O, and NQ{sub 3}, where Q =H, D, T) are decomposed (cracked) and removed by Zr-Mn-Fe without absorbing elemental hydrogen isotopes. If the tritium content of the glovebox atmosphere becomes unacceptably high, the getter system can rapidly strip the glovebox atmosphere of all hydrogen isotopes by absorption on the Zr{sub 2}Fe, thus lessening the burden on the facility waste gas treatment system. The getter system was designed for high flowrate ( > 100 1/min), which is achieved by using a honeycomb support for the getter pellets and 1.27-cm diameter tubing throughout the system for reduced pressure drop. The novel getter bed design also includes an integral preheater and copper liner to accommodate swelling of the getter pellets, which occurs during loading with oxygen and carbon impurities. Non-tritium functional tests were conducted to determine the gettering efficiencies at different getter bed temperatures and flowrates by recirculating gas through the system from, a 6-m{sup 3} glovebox containing known concentrations of impurities. (authors)

  18. Performance Testing of Jefferson Lab 12 GeV Helium Screw Compressors

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

    Knudsen, P.; Ganni, V.; Dixon, K.; Norton, R.; Creel, J.

    2015-08-10

    Oil injected screw compressors have essentially superseded all other types of compressors in modern helium refrigeration systems due to their large displacement capacity, reliability, minimal vibration, and capability of handling helium's high heat of compression. At the present state of compressor system designs for helium refrigeration systems, typically two-thirds of the lost input power is due to the compression system. It is important to understand the isothermal and volumetric efficiencies of these machines to help properly design the compression system to match the refrigeration process. It is also important to identify those primary compressor skid exergetic loss mechanisms which maymore » be reduced, thereby offering the possibility of significantly reducing the input power to helium refrigeration processes which are extremely energy intensive. This paper summarizes the results collected during the commissioning of the new compressor system for Jefferson Lab's (JLab's) 12 GeV upgrade. The compressor skid packages were designed by JLab and built to print by industry. They incorporate a number of modifications not typical of helium screw compressor packages and most importantly allow a very wide range of operation so that JLab's patented Floating Pressure Process can be fully utilized. This paper also summarizes key features of the skid design that allow this process and facilitate the maintenance and reliability of these helium compressor systems.« less

  19. The initiation and propagation of helium detonations in white dwarf envelopes

    SciTech Connect (OSTI)

    Shen, Ken J. [Department of Astronomy and Theoretical Astrophysics Center, University of California, Berkeley, CA 94720 (United States); Moore, Kevin, E-mail: kenshen@astro.berkeley.edu [Department of Applied Mathematics and Statistics, University of California, Santa Cruz, CA 95064 (United States)

    2014-12-10

    Detonations in helium-rich envelopes surrounding white dwarfs have garnered attention as triggers of faint thermonuclear '.Ia' supernovae and double detonation Type Ia supernovae. However, recent studies have found that the minimum size of a hotspot that can lead to a helium detonation is comparable to, or even larger than, the white dwarf's pressure scale height, casting doubt on the successful ignition of helium detonations in these systems. In this paper, we examine the previously neglected effects of C/O pollution and a full nuclear reaction network, and we consider hotspots with spatially constant pressure in addition to constant density hotspots. We find that the inclusion of these effects significantly decreases the minimum hotspot size for helium-rich detonation ignition, making detonations far more plausible during turbulent shell convection or during double white dwarf mergers. The increase in burning rate also decreases the minimum shell mass in which a helium detonation can successfully propagate and alters the composition of the shell's burning products. The ashes of these low-mass shells consist primarily of silicon, calcium, and unburned helium and metals and may explain the high-velocity spectral features observed in most Type Ia supernovae.

  20. Performance Testing of Jefferson Lab 12 GeV Helium Screw Compressors

    SciTech Connect (OSTI)

    Knudsen, P.; Ganni, V.; Dixon, K.; Norton, R.; Creel, J.

    2015-08-10

    Oil injected screw compressors have essentially superseded all other types of compressors in modern helium refrigeration systems due to their large displacement capacity, reliability, minimal vibration, and capability of handling helium's high heat of compression. At the present state of compressor system designs for helium refrigeration systems, typically two-thirds of the lost input power is due to the compression system. It is important to understand the isothermal and volumetric efficiencies of these machines to help properly design the compression system to match the refrigeration process. It is also important to identify those primary compressor skid exergetic loss mechanisms which may be reduced, thereby offering the possibility of significantly reducing the input power to helium refrigeration processes which are extremely energy intensive. This paper summarizes the results collected during the commissioning of the new compressor system for Jefferson Lab's (JLab's) 12 GeV upgrade. The compressor skid packages were designed by JLab and built to print by industry. They incorporate a number of modifications not typical of helium screw compressor packages and most importantly allow a very wide range of operation so that JLab's patented Floating Pressure Process can be fully utilized. This paper also summarizes key features of the skid design that allow this process and facilitate the maintenance and reliability of these helium compressor systems.

  1. AVLIS enrichment of medical isotopes

    SciTech Connect (OSTI)

    Haynam, C.A.; Scheibner, K.F.; Stern, R.C.; Worden, E.F.

    1996-12-31

    Under the Sponsorship of the United states Enrichment Corporation (USEC), we are currently investigating the large scale separation of several isotopes of medical interest using atomic vapor isotope separation (AVLIS). This work includes analysis and experiments in the enrichment of thallium 203 as a precursor to the production of thallium 201 used in cardiac imaging following heart attacks, on the stripping of strontium 84 from natural strontium as precursor to the production of strontium 89, and on the stripping of lead 210 from lead used in integrated circuits to reduce the number of alpha particle induced logic errors.

  2. Isotope geochronology of metamorphic processes

    SciTech Connect (OSTI)

    Ovchinnikov, L.N.; Voronovskiy, S.N.; Ovchinnikova, L.V.

    1986-05-01

    The long history of the earth and its crust is a history of uninterrupted and continuing transformation, making metamorphism the most common and most extensive geological process on this planet. Metamorphism has occurred in all epochs and is a factor in all endogenic processes: geodynamics, magmatism, and the action of intratelluric fluids. But it varies in scale, type, and mechanism, and is always combined with metasomatism - the chemical and mineral transformation of material. This paper discusses methodological principles of isotope dating, laws characterizing changes in indicator minerals, internal stability of isotopic systems, and interesting geological problems. 13 references.

  3. Atomic-scale mechanisms of helium bubble hardening in iron

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

    Osetskiy, Yury N.; Stoller, Roger E.

    2015-06-03

    Generation of helium due to (n,α) transmutation reactions changes the response of structural materials to neutron irradiation. The whole process of radiation damage evolution is affected by He accumulation and leads to significant changes in the material s properties. A population of nanometric He-filled bubbles affects mechanical properties and the impact can be quite significant because of their high density. Understanding how these basic mechanisms affect mechanical properties is necessary for predicting radiation effects. In this paper we present an extensive study of the interactions between a moving edge dislocation and bubbles using atomic-scale modeling. We focus on the effectmore » of He bubble size and He concentration inside bubbles. Thus, we found that ability of bubbles to act as an obstacle to dislocation motion is close to that of voids when the He-to-vacancy ratio is in the range from 0 to 1. A few simulations made at higher He contents demonstrated that the interaction mechanism is changed for over-pressurized bubbles and they become weaker obstacles. The results are discussed in light of post-irradiation materials testing.« less

  4. Atomic-scale mechanisms of helium bubble hardening in iron

    SciTech Connect (OSTI)

    Osetskiy, Yury N.; Stoller, Roger E.

    2015-06-03

    Generation of helium due to (n,α) transmutation reactions changes the response of structural materials to neutron irradiation. The whole process of radiation damage evolution is affected by He accumulation and leads to significant changes in the material s properties. A population of nanometric He-filled bubbles affects mechanical properties and the impact can be quite significant because of their high density. Understanding how these basic mechanisms affect mechanical properties is necessary for predicting radiation effects. In this paper we present an extensive study of the interactions between a moving edge dislocation and bubbles using atomic-scale modeling. We focus on the effect of He bubble size and He concentration inside bubbles. Thus, we found that ability of bubbles to act as an obstacle to dislocation motion is close to that of voids when the He-to-vacancy ratio is in the range from 0 to 1. A few simulations made at higher He contents demonstrated that the interaction mechanism is changed for over-pressurized bubbles and they become weaker obstacles. The results are discussed in light of post-irradiation materials testing.

  5. Performance Characterization of the Production Facility Prototype Helium Flow System

    SciTech Connect (OSTI)

    Woloshun, Keith Albert; Dale, Gregory E.; Dalmas, Dale Allen; Romero, Frank Patrick

    2015-12-16

    The roots blower in use at ANL for in-beam experiments and also at LANL for flow tests was sized for 12 mm diameter disks and significantly less beam heating. Currently, the disks are 29 mm in diameter, with a 12 mm FWHM Gaussian beam spot at 42 MeV and 2.86 μA on each side of the target, 5.72 μA total. The target design itself is reported elsewhere. With the increased beam heating, the helium flow requirement increased so that a larger blower was need for a mass flow rate of 400 g/s at 2.76 MPa (400 psig). An Aerzen GM 12.4 blower was selected, and is currently being installed at the LANL facility for target and component flow testing. This report describes this blower/motor/pressure vessel package and the status of the facility preparations. Blower performance (mass flow rate as a function of loop pressure drop) was measured at 4 blower speeds. Results are reported below.

  6. Sustainable Nanomaterials Industry Perspective

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

    Industry Perspective U.S. Department of Energy Advanced Manufacturing Office Sustainable ... Uses renewable resources grown with sustainable forestry practices Encourages ...

  7. Online Catalog of Isotope Products from DOE's National Isotope Development Center

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

    The National Isotope Development Center (NIDC) interfaces with the User Community and manages the coordination of isotope production across the facilities and business operations involved in the production, sale, and distribution of isotopes. A virtual center, the NIDC is funded by the Isotope Development and Production for Research and Applications (IDPRA) subprogram of the Office of Nuclear Physics in the U.S. Department of Energy Office of Science. The Isotope subprogram supports the production, and the development of production techniques of radioactive and stable isotopes that are in short supply for research and applications. Isotopes are high-priority commodities of strategic importance for the Nation and are essential for energy, medical, and national security applications and for basic research; a goal of the program is to make critical isotopes more readily available to meet domestic U.S. needs. This subprogram is steward of the Isotope Production Facility (IPF) at Los Alamos National Laboratory (LANL), the Brookhaven Linear Isotope Producer (BLIP) facility at BNL, and hot cell facilities for processing isotopes at ORNL, BNL and LANL. The subprogram also coordinates and supports isotope production at a suite of university, national laboratory, and commercial accelerator and reactor facilities throughout the Nation to promote a reliable supply of domestic isotopes. The National Isotope Development Center (NIDC) at ORNL coordinates isotope production across the many facilities and manages the business operations of the sale and distribution of isotopes.

  8. Science with Beams of Radioactive Isotopes

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

    Pacifichem 2015 Pacifichem 2015 The International Chemical Congress of Pacific Basin Societies Science with Beams of Radioactive Isotopes (# 340) Honolulu, Hawaii, USA December 15-20, 2015 Science with Beams of Radioactive Isotopes (# 340) All of the elements that make up the periodic chart have been created from nuclear reactions. Many of the stable nuclei in the universe are daughters of unstable isotopes, and their true origin lies in the stellar reactions of these radioactive isotopes. Thus

  9. Isotopes for cancer and cardiac care

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

    Isotopes for cancer Isotopes for cancer and cardiac care Eva Birnbaum is interviewed on KSFR radio on the Lab's Isotope Program February 4, 2016 hot cell facility A worker uses remote manipulator arms to handle a highly radioactive target inside the Lab's radiochemistry hot cell facility. Isotopes from Los Alamos are used for the diagnosis of cardiac disease, for the calibration of PET scanners which in turn diagnose cancer, neurological disease, inflammatory diseases, trauma, and other

  10. Isotope Production in Light of Increasing Demand

    SciTech Connect (OSTI)

    Patton, B.

    2004-10-05

    This presentation is a part of the panel discussion on isotope production in light of increasing demand.

  11. Isotope Cancer Treatment Research at LANL

    ScienceCinema (OSTI)

    Weidner, John; Nortier, Meiring

    2014-06-02

    Los Alamos National Laboratory has produced medical isotopes for diagnostic and imaging purposes for more than 30 years. Now LANL researchers have branched out into isotope cancer treatment studies. New results show that an accelerator-based approach can produce clinical trial quantities of actinium-225, an isotope that has promise as a way to kill tumors without damaging surrounding healthy cells.

  12. Isotope Cancer Treatment Research at LANL

    SciTech Connect (OSTI)

    Weidner, John; Nortier, Meiring

    2012-04-11

    Los Alamos National Laboratory has produced medical isotopes for diagnostic and imaging purposes for more than 30 years. Now LANL researchers have branched out into isotope cancer treatment studies. New results show that an accelerator-based approach can produce clinical trial quantities of actinium-225, an isotope that has promise as a way to kill tumors without damaging surrounding healthy cells.

  13. Dry phase reactor for generating medical isotopes

    DOE Patents [OSTI]

    Mackie, Thomas Rockwell; Heltemes, Thad Alexander

    2016-05-03

    An apparatus for generating medical isotopes provides for the irradiation of dry-phase, granular uranium compounds which are then dissolved in a solvent for separation of the medical isotope from the irradiated compound. Once the medical isotope is removed, the dissolved compound may be reconstituted in dry granular form for repeated irradiation.

  14. ALTERNATIVES TO HELIUM-3 FOR NEUTRON MULTIPLICITY DETECTORS

    SciTech Connect (OSTI)

    Ely, James H.; Siciliano, Edward R.; Swinhoe, Martyn T.

    2012-02-07

    Collaboration between the Pacific Northwest National Laboratory (PNNL) and the Los Alamos National Laboratory (LANL) is underway to evaluate neutron detection technologies that might replace the high-pressure helium (3He) tubes currently used in neutron multiplicity counter for safeguards applications. The current stockpile of 3He is diminishing and alternatives are needed for a variety of neutron detection applications including multiplicity counters. The first phase of this investigation uses a series of Monte Carlo calculations to simulate the performance of an existing neutron multiplicity counter configuration by replacing the 3He tubes in a model for that counter with candidate alternative technologies. These alternative technologies are initially placed in approximately the same configuration as the 3He tubes to establish a reference level of performance against the 3He-based system. After these reference-level results are established, the configurations of the alternative models will be further modified for performance optimization. The 3He model for these simulations is the one used by LANL to develop and benchmark the Epithermal Neutron Multiplicity Counter (ENMC) detector, as documented by H.O. Menlove, et al. in the 2004 LANL report LA-14088. The alternative technologies being evaluated are the boron-tri-fluoride-filled proportional tubes, boron-lined tubes, and lithium coated materials previously tested as possible replacements in portal monitor screening applications, as documented by R.T. Kouzes, et al. in the 2010 PNNL report PNNL-72544 and NIM A 623 (2010) 1035–1045. The models and methods used for these comparative calculations will be described and preliminary results shown

  15. Isotope hydrology of catchment basins: lithogenic and cosmogenic isotopic systems

    SciTech Connect (OSTI)

    Nimz, G. J., LLNL

    1998-06-01

    A variety of physical processes affect solute concentrations within catchment waters. The isotopic compositions of the solutes can indicate which processes have determined the observed concentrations. These processes together constitute the physical history of the water. Many solutes in natural waters are derived from the interaction between the water and the rock and/or soil within the system - these are termed `lithogenic` solutes. The isotopic compositions of these solutes provide information regarding rock-water interactions. Many other solutes have their isotopic compositions determined both within and outside of the catchment - i.e., in addition to being derived from catchment rock and soil, they are solutes that are also transported into the catchment. Important members of this group include solutes that have isotopic compositions produced by atomic particle interactions with other nuclides. The source of the atomic particles can be cosmic radiation (producing `cosmogenic` nuclides in the atmosphere and land surface), anthropogenic nuclear reactions (producing `thermonuclear` nuclides), or radioactive and fission decay of naturally-occurring elements, principally {sup 238}U (producing `in-situ` lithogenic nuclides in the deep subsurface). Current language usage often combines all of the atomic particle-produced nuclides under the heading `cosmogenic nuclides`, and for simplicity we will often follow that usage here, although always indicating which variety is being discussed. This paper addresses the processes that affect the lithogenic and cosmogenic solute concentrations in catchment waters, and how the isotopic compositions of the solutes can be used in integrative ways to identify these processes, thereby revealing the physical history of the water within a catchment system. The concept of a `system` is important in catchment hydrology. A catchment is the smallest landscape unit that can both participate in all of the aspects of the hydrologic cycle and

  16. Measurements of the Helium Form Factors at JLab

    SciTech Connect (OSTI)

    Khrosinkova, Elena

    2007-10-26

    An experiment to measure elastic electron scattering off {sup 3}He and {sup 4}He at large momentum transfers is presented. The experiment was carried out in the Hall A Facility of Jefferson Lab. Elastic electron scattering off {sup 3}He was measured at forward and backward electron scattering angles to extract the isotope's charge and magnetic form factors. The charge form factor of {sup 4}He will be extracted from forward-angle electron scattering angle measurements. The data are expected to significantly extend and improve the existing measurements of the three- and four-body form factors. The results will be crucial for the establishment of a canonical standard model for the few-body nuclear systems and for testing predictions of quark dimensional scaling and hybrid nucleon-quark models.

  17. Measuring SNM Isotopic Distributions using FRAM

    SciTech Connect (OSTI)

    Geist, William H.

    2015-12-02

    The first group of slides provides background information on the isotopic composition of plutonium. It is shown that 240Pu is the critical isotope in neutron coincidence/multiplicity counting. Next, response function analysis to determine isotopic composition is discussed. The isotopic composition can be determined by measuring the net peak counts from each isotope and then taking the ratio of the counts for each isotope relative to the total counts for the element. Then FRAM (Fixed energy Response function Analysis with Multiple efficiencies) is explained. FRAM can control data acquisition, automatically analyze newly acquired data, analyze previously acquired data, provide information on the quality of the analysis, and facilitate analysis in unusual situations (non-standard energy calibrations, gamma rays from non-SNM isotopes, poor spectra (within limits)).

  18. Assessment of Embrittlement of VHTR Structural Alloys in Impure Helium Environments

    SciTech Connect (OSTI)

    Crone, Wendy; Cao, Guoping; Sridhara, Kumar

    2013-05-31

    The helium coolant in high-temperature reactors inevitably contains low levels of impurities during steady-state operation, primarily consisting of small amounts of H{sub 2}, H{sub 2}O, CH{sub 4}, CO, CO{sub 2}, and N{sub 2} from a variety of sources in the reactor circuit. These impurities are problematic because they can cause significant long-term corrosion in the structural alloys used in the heat exchangers at elevated temperatures. Currently, the primary candidate materials for intermediate heat exchangers are Alloy 617, Haynes 230, Alloy 800H, and Hastelloy X. This project will evaluate the role of impurities in helium coolant on the stress-assisted grain boundary oxidation and creep crack growth in candidate alloys at elevated temperatures. The project team will: • Evaluate stress-assisted grain boundary oxidation and creep crack initiation and crack growth in the temperature range of 500-850°C in a prototypical helium environment. • Evaluate the effects of oxygen partial pressure on stress-assisted grain boundary oxidation and creep crack growth in impure helium at 500°C, 700°C, and 850°C respectively. • Characterize the microstructure of candidate alloys after long-term exposure to an impure helium environment in order to understand the correlation between stress-assisted grain boundary oxidation, creep crack growth, material composition, and impurities in the helium coolant. • Evaluate grain boundary engineering as a method to mitigate stress-assisted grain boundary oxidation and creep crack growth of candidate alloys in impure helium. The maximum primary helium coolant temperature in the high-temperature reactor is expected to be 850-1,000°C.Corrosion may involve oxidation, carburization, or decarburization mechanisms depending on the temperature, oxygen partial pressure, carbon activity, and alloy composition. These corrosion reactions can substantially affect long-term mechanical properties such as crack- growth rate and fracture

  19. Laser ablation molecular isotopic spectrometry of carbon isotopes

    SciTech Connect (OSTI)

    Bol'shakov, Alexander A.; Jain, Jinesh; Russo, Richard E.; McIntyre, Dustin; Mao, Xianglei

    2015-08-28

    Quantitative determination of carbon isotopes using Laser Ablation Molecular Isotopic Spectrometry (LAMIS) is described. Optical emission of diatomic molecules CN and C2 is used in these measurements. Two quantification approaches are presented:empirical calibration of spectra using a set of reference standards and numerical fitting of a simulated spectrum to the experimental one. Formation mechanisms of C2 and CN in laser ablation plasma are briefly reviewed to provide insights for implementation of LAMIS measurements. A simulated spectrum of the 12C2 Swan system was synthesized using four constituents within 473.5–476.5 nm. Simulation included three branches of 12C2 (1-0), branches R(0-0) and R(1-1), and branch P(9-8) of 12C2. Spectral positions of the tail lines in R(0-0) and R(1-1) were experimentally measured, since they were not accurately known before. The Swan band (1-0) of the isotopologue 13C12C was also simulated. Fitting to the experimental spectrumyielded the ratio 13C/12C = 1.08% in a good agreement with measurements by isotope ratio mass spectrometry. LAMIS promises to be useful in coal, oil and shale exploration, carbon sequestration monitoring, and agronomy studies

  20. Forced Two-Phase Helium Cooling Scheme for the Mu2e Transport Solenoid

    SciTech Connect (OSTI)

    Tatkowski, G.; Cheban, S.; Dhanaraj, N.; Evbota, D.; Lopes, M.; Nicol, T.; Sanders, R.; Schmitt, R.; Voirin, E.

    2015-01-01

    The Mu2e Transport Solenoid (TS) is an S-shaped magnet formed by two separate but similar magnets, TS-u and TS-d. Each magnet is quarter-toroid shaped with a centerline radius of approximately 3 m utilizing a helium cooling loop consisting of 25 to 27 horizontal-axis rings connected in series. This cooling loop configuration has been deemed adequate for cooling via forced single phase liquid helium; however it presents major challenges to forced two-phase flow such as “garden hose” pressure drop, concerns of flow separation from tube walls, difficulty of calculation, etc. Even with these disadvantages, forced two-phase flow has certain inherent advantages which make it a more attractive option than forced single phase flow. It is for this reason that the use of forced two-phase flow was studied for the TS magnets. This paper will describe the analysis using helium-specific pressure drop correlations, conservative engineering approach, helium properties calculated and updated at over fifty points, and how the results compared with those in literature. Based on the findings, the use of forced-two phase helium is determined to be feasible for steady-state cooling of the TS solenoids

  1. Helium embrittlement model and program plan for weldability of ITER materials

    SciTech Connect (OSTI)

    Louthan, M.R. Jr.; Kanne, W.R. Jr.; Tosten, M.H.; Rankin, D.T.; Cross, B.J.

    1997-02-01

    This report presents a refined model of how helium embrittles irradiated stainless steel during welding. The model was developed based on experimental observations drawn from experience at the Savannah River Site and from an extensive literature search. The model shows how helium content, stress, and temperature interact to produce embrittlement. The model takes into account defect structure, time, and gradients in stress, temperature and composition. The report also proposes an experimental program based on the refined helium embrittlement model. A parametric study of the effect of initial defect density on the resulting helium bubble distribution and weldability of tritium aged material is proposed to demonstrate the roll that defects play in embrittlement. This study should include samples charged using vastly different aging times to obtain equivalent helium contents. Additionally, studies to establish the minimal sample thickness and size are needed for extrapolation to real structural materials. The results of these studies should provide a technical basis for the use of tritium aged materials to predict the weldability of irradiated structures. Use of tritium charged and aged material would provide a cost effective approach to developing weld repair techniques for ITER components.

  2. Elucidation of fundamental properties of helium in metals by nuclear magnetic resonance techniques

    SciTech Connect (OSTI)

    Abell, G.C.

    1990-01-01

    The nuclear magnetic resonance (NMR) properties of very high density {sup 3}He in metals are discussed in the context of the corresponding properties in relatively high density bulk {sup 3}He. In particular, the effects of the {sup 3}He diffusion on the contribution of the {sup 3}He-{sup 3}He dipolar interaction to the lineshape and to the spin-lattice relaxation parameter (T{sub 1}) are described. It is shown that the temperature dependence of the lineshape and of T{sub 1} are independent sources of information about helium density and also about helium diffusivity. Moreover, T{sub 1} is shown to be a sensitive indicator of melting transitions in bulk {sup 3}He. Palladium tritide is presented as a model system for NMR studies of {sup 3}He in metals. Experimental NMR studies of this system reveal behavior analogous to what has been observed for bulk helium. Evidence for a {sup 3}He phase transition near 250 K is provided by the temperature dependence of T{sub 1}. Assuming this to be a melting transition, a density is obtained from the bulk helium EOS that is in good agreement with theory and with swelling measurements on related metal tritides. {sup 3}He NMR measurements have also provided information about the density distribution, helium diffusivity, and mean bubble size in palladium tritide. 22 refs., 8 figs.

  3. Helium release and microstructural changes in Er(D,T)2-x3Hex films).

    SciTech Connect (OSTI)

    Gelles, D. S.; Browning, James Frederick; Snow, Clark Sheldon; Banks, James Clifford; Mangan, Michael A.; Rodriguez, Mark Andrew; Brewer, Luke N.; Kotula, Paul Gabriel

    2007-12-01

    Er(D,T){sub 2-x} {sup 3}He{sub x}, erbium di-tritide, films of thicknesses 500 nm, 400 nm, 300 nm, 200 nm, and 100 nm were grown and analyzed by Transmission Electron Microscopy, X-Ray Diffraction, and Ion Beam Analysis to determine variations in film microstructure as a function of film thickness and age, due to the time-dependent build-up of {sup 3}He in the film from the radioactive decay of tritium. Several interesting features were observed: One, the amount of helium released as a function of film thickness is relatively constant. This suggests that the helium is being released only from the near surface region and that the helium is not diffusing to the surface from the bulk of the film. Two, lenticular helium bubbles are observed as a result of the radioactive decay of tritium into {sup 3}He. These bubbles grow along the [111] crystallographic direction. Three, a helium bubble free zone, or 'denuded zone' is observed near the surface. The size of this region is independent of film thickness. Four, an analysis of secondary diffraction spots in the Transmission Electron Microscopy study indicate that small erbium oxide precipitates, 5-10 nm in size, exist throughout the film. Further, all of the films had large erbium oxide inclusions, in many cases these inclusions span the depth of the film.

  4. Analysis of hydrogen isotope mixtures

    DOE Patents [OSTI]

    Villa-Aleman, Eliel

    1994-01-01

    An apparatus and method for determining the concentrations of hydrogen isotopes in a sample. Hydrogen in the sample is separated from other elements using a filter selectively permeable to hydrogen. Then the hydrogen is condensed onto a cold finger or cryopump. The cold finger is rotated as pulsed laser energy vaporizes a portion of the condensed hydrogen, forming a packet of molecular hydrogen. The desorbed hydrogen is ionized and admitted into a mass spectrometer for analysis.

  5. Commissioning of helium compression system for the 12 GeV refrigerator

    SciTech Connect (OSTI)

    Knudsen, Peter N.; Ganni, Venkatarao; Dixon, Kelly D.; Norton, Robert O.; Creel, Jonathan D.; Arenius, Dana M.

    2014-01-01

    The compressor system used for the Jefferson Lab (JLab) 12 GeV upgrade, also known as the CHL-2 compressor system, incorporates many design changes to the typical compressor skid design to improve the efficiency, reliability and maintainability from previous systems. These include a considerably smaller bulk oil separator design that does not use coalescing elements/media, automated control of cooling oil injection based on the helium discharge temperature, a helium after-cooler design that is designed for and promotes coalescing of residual oil and a variable speed bearing oil pump to reduce oil bypass. The CHL-2 helium compression system has five compressors configured with four pressure levels that supports the three pressure levels in the cold box. This paper will briefly review several of these improvements and discuss some of the recent commissioning results.

  6. Ab initio study of formation, migration and binding properties of helium-vacancy clusters in aluminum

    SciTech Connect (OSTI)

    Yang, Li; Zu, Xiaotao T.; Gao, Fei

    2008-08-01

    Ab initio calculations based on density functional theory have been performed to study the dissolution and migration of helium, and the stability of small helium-vacancy clusters HenVm (n, m=0 to 4) in aluminum. The results indicate that the octahedral configuration is more stable than the tetrahedral. Interstitial helium atoms are predicted to have attractive interactions and jump between two octahedral sites via an intermediate tetrahedral site with low migration energy of 0.10 eV. The binding energies of an interstitial He atom and an isolated vacancy to a HenVm cluster are also obtained from the calculated formation energies of the clusters. We find that the divacancy and tri--vacancy clusters are not stable, but He atoms can increase the stability of vacancy clusters. The interactions of He atoms with a vacancy are found to be in good agreement with the experimental results.

  7. Molecular-dynamics analysis of mobile helium cluster reactions near surfaces of plasma-exposed tungsten

    SciTech Connect (OSTI)

    Hu, Lin; Maroudas, Dimitrios; Hammond, Karl D.; Wirth, Brian D.

    2015-10-28

    We report the results of a systematic atomic-scale analysis of the reactions of small mobile helium clusters (He{sub n}, 4 ≤ n ≤ 7) near low-Miller-index tungsten (W) surfaces, aiming at a fundamental understanding of the near-surface dynamics of helium-carrying species in plasma-exposed tungsten. These small mobile helium clusters are attracted to the surface and migrate to the surface by Fickian diffusion and drift due to the thermodynamic driving force for surface segregation. As the clusters migrate toward the surface, trap mutation (TM) and cluster dissociation reactions are activated at rates higher than in the bulk. TM produces W adatoms and immobile complexes of helium clusters surrounding W vacancies located within the lattice planes at a short distance from the surface. These reactions are identified and characterized in detail based on the analysis of a large number of molecular-dynamics trajectories for each such mobile cluster near W(100), W(110), and W(111) surfaces. TM is found to be the dominant cluster reaction for all cluster and surface combinations, except for the He{sub 4} and He{sub 5} clusters near W(100) where cluster partial dissociation following TM dominates. We find that there exists a critical cluster size, n = 4 near W(100) and W(111) and n = 5 near W(110), beyond which the formation of multiple W adatoms and vacancies in the TM reactions is observed. The identified cluster reactions are responsible for important structural, morphological, and compositional features in the plasma-exposed tungsten, including surface adatom populations, near-surface immobile helium-vacancy complexes, and retained helium content, which are expected to influence the amount of hydrogen re-cycling and tritium retention in fusion tokamaks.

  8. Cryogenic system with GM cryocooler for krypton, xenon separation from hydrogen-helium purge gas

    SciTech Connect (OSTI)

    Chu, X. X.; Zhang, D. X.; Qian, Y.; Liu, W.; Zhang, M. M.; Xu, D.

    2014-01-29

    In the thorium molten salt reactor (TMSR), fission products such as krypton, xenon and tritium will be produced continuously in the process of nuclear fission reaction. A cryogenic system with a two stage GM cryocooler was designed to separate Kr, Xe, and H{sub 2} from helium purge gas. The temperatures of two stage heat exchanger condensation tanks were maintained at about 38 K and 4.5 K, respectively. The main fluid parameters of heat transfer were confirmed, and the structural heat exchanger equipment and cold box were designed. Designed concentrations after cryogenic separation of Kr, Xe and H{sub 2} in helium recycle gas are less than 1 ppb.

  9. Effect of helium growth and carbon impurities on the properties of aged metal tritides

    SciTech Connect (OSTI)

    McConville, G.T.; Menke, D.A.; West, D.; Woods, C.M.

    1995-10-01

    The interaction of tritium with metals is made complex by two phenomena. The beta decay in the metal produces {sup 3}He. The helium moves to form bubbles. We shall show that the growth of the bubbles produces a two stage swelling of the metal coming first from the appearance of the helium and second from the relaxation of the lattice disorder caused by the bubble growth. The second phenomenon is the steady state ion and free radical concentration in the tritium over gas which interacts with impurities on the metal surface. We shall show that the reaction rates are much faster than for normal hydrogen cleaning. 12 refs., 7 figs., 3 tabs.

  10. SPHERICALLY SYMMETRIC NLTE MODEL ATMOSPHERES OF HOT HYDROGEN-HELIUM FIRST STARS

    SciTech Connect (OSTI)

    Kubat, Jiri

    2012-12-15

    We present results of our calculations of NLTE model stellar atmospheres for hot Population III stars composed of hydrogen and helium. We use our own computer code for the calculation of spherically symmetric NLTE model atmospheres in hydrostatic and radiative equilibrium. The model atmospheres are then used for the calculation of emergent fluxes. These fluxes serve to evaluate the flow of high-energy photons for energies higher than ionization energies of hydrogen and helium, the so-called ionizing photon fluxes. We also present the time evolution of the ionizing photon fluxes.

  11. Application of JLab 12GeV helium refrigeration system for the FRIB accelerator at MSU

    SciTech Connect (OSTI)

    Ganni, Venkatarao; Knudsen, Peter N.; Arenius, Dana M.; Casagrande, Fabio

    2014-01-01

    The planned approach to have a turnkey helium refrigeration system for the MSU-FRIB accelerator system, encompassing the design, fabrication, installation and commissioning of the 4.5-K refrigerator cold box(es), cold compression system, warm compression system, gas management, oil removal and utility/ancillary systems, was found to be cost prohibitive. Following JLab’s suggestion, MSU-FRIB accelerator management made a formal request to evaluate the applicability of the recently designed 12GeV JLab cryogenic system for this application. The following paper will outline the findings and the planned approach for the FRIB helium refrigeration system.

  12. Application of JLab 12GeV helium refrigeration system for the FRIB accelerator at MSU

    SciTech Connect (OSTI)

    Ganni, V.; Knudsen, P.; Arenius, D.; Casagrande, F.

    2014-01-29

    The planned approach to have a turnkey helium refrigeration system for the MSU-FRIB accelerator system, encompassing the design, fabrication, installation and commissioning of the 4.5-K refrigerator cold box(es), cold compression system, warm compression system, gas management, oil removal and utility/ancillary systems, was found to be cost prohibitive. Following JLab’s suggestion, MSU-FRIB accelerator management made a formal request to evaluate the applicability of the recently designed 12GeV JLab cryogenic system for this application. The following paper will outline the findings and the planned approach for the FRIB helium refrigeration system.

  13. Stable Isotope Enrichment Capabilities at ORNL

    SciTech Connect (OSTI)

    Egle, Brian; Aaron, W Scott; Hart, Kevin J

    2013-01-01

    The Oak Ridge National Laboratory (ORNL) and the US Department of Energy Nuclear Physics Program have built a high-resolution Electromagnetic Isotope Separator (EMIS) as a prototype for reestablishing a US based enrichment capability for stable isotopes. ORNL has over 60 years of experience providing enriched stable isotopes and related technical services to the international accelerator target community, as well as medical, research, industrial, national security, and other communities. ORNL is investigating the combined use of electromagnetic and gas centrifuge isotope separation technologies to provide research quantities (milligram to several kilograms) of enriched stable isotopes. In preparation for implementing a larger scale production facility, a 10 mA high-resolution EMIS prototype has been built and tested. Initial testing of the device has simultaneously collected greater than 98% enriched samples of all the molybdenum isotopes from natural abundance feedstock.

  14. Effects of helium implantation on the tensile properties and microstructure of Ni??P?? metallic glass nanostructures

    SciTech Connect (OSTI)

    Liontas, Rachel; Gu, X. Wendy; Fu, Engang; Wang, Yongqiang; Li, Nan; Mara, Nathan; Greer, Julia R.

    2014-09-10

    We report fabrication and nanomechanical tension experiments on as-fabricated and helium-implanted ~130 nm diameter Ni??P?? metallic glass nano-cylinders. The nano-cylinders were fabricated by a templated electroplating process and implanted with He? at energies of 50, 100, 150, and 200 keV to create a uniform helium concentration of ~3 at. % throughout the nano-cylinders. Transmission electron microscopy (TEM) imaging and through-focus analysis reveal that the specimens contained ~2 nm helium bubbles distributed uniformly throughout the nano-cylinder volume. In-situ tensile experiments indicate that helium-implanted specimens exhibit enhanced ductility as evidenced by a 2-fold increase in plastic strain over as-fabricated specimens, with no sacrifice in yield and ultimate tensile strengths. This improvement in mechanical properties suggests that metallic glasses may actually exhibit a favorable response to high levels of helium implantation.

  15. Effects of helium implantation on the tensile properties and microstructure of Ni₇₃P₂₇ metallic glass nanostructures

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

    Liontas, Rachel; Gu, X. Wendy; Fu, Engang; Wang, Yongqiang; Li, Nan; Mara, Nathan; Greer, Julia R.

    2014-09-10

    We report fabrication and nanomechanical tension experiments on as-fabricated and helium-implanted ~130 nm diameter Ni₇₃P₂₇ metallic glass nano-cylinders. The nano-cylinders were fabricated by a templated electroplating process and implanted with He⁺ at energies of 50, 100, 150, and 200 keV to create a uniform helium concentration of ~3 at. % throughout the nano-cylinders. Transmission electron microscopy (TEM) imaging and through-focus analysis reveal that the specimens contained ~2 nm helium bubbles distributed uniformly throughout the nano-cylinder volume. In-situ tensile experiments indicate that helium-implanted specimens exhibit enhanced ductility as evidenced by a 2-fold increase in plastic strain over as-fabricated specimens, with nomore » sacrifice in yield and ultimate tensile strengths. This improvement in mechanical properties suggests that metallic glasses may actually exhibit a favorable response to high levels of helium implantation.« less

  16. METHOD AND APPARATUS FOR COLLECTING ISOTOPES

    DOE Patents [OSTI]

    Leyshon, W.E.

    1957-08-01

    A method and apparatus for collecting isotopes having a high vapor pressure, such as isotopes of mercury, in a calutron are described. Heretofore, the collected material would vaporize and escape from the ion receiver as fast as it was received. By making the receiver of pure silver, the mercury isotopes form a nonvolatile amalgam with the silver at the water cooled temperature of the receiver, and the mercury is thus retained.

  17. FIRST_Research Perspective_Li

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

    1. Structure factor obtained from MD (a) and SAXS (b) at different temperatures: comparison of spatial heterogeneity from snapshots (c) of DILs (top) and MILs (bottom) FIRST Center Research Perspective: Nanoscale Heterogeneity and Dynamics of Room Temperature Ionic Liquids Song Li Vanderbilt University Jianchang Guo, Kee Sung Han, Jose L. Bañuelos, Edward W. Hagaman, Robert W. Shaw Oak Ridge National Laboratory Research Summary: An increase of the alkyl chain length of the cation of room

  18. Categorical Exclusion 4577: Lithium Isotope Separation & Enrichment...

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

    Lithium Isotope Separation & Enrichment Technologies (4577) Program or Field Office: Y-12 Site Office Location(s) (CityCountyState): Oak Ridge, Anderson County, Tennessee...

  19. Atomic vapor laser isotope separation process

    DOE Patents [OSTI]

    Wyeth, Richard W.; Paisner, Jeffrey A.; Story, Thomas

    1990-01-01

    A laser spectroscopy system is utilized in an atomic vapor laser isotope separation process. The system determines spectral components of an atomic vapor utilizing a laser heterodyne technique.

  20. Isotope production agreement benefits medical patients | National...

    National Nuclear Security Administration (NNSA)

    LLC (NSTec), and Henderson, Nevada-based Global Medical Isotope Systems, LLC (GMIS). ... Known primarily as the management and operations contractor for the Nevada National ...

  1. Method for isotope enrichment by photoinduced chemiionization

    DOE Patents [OSTI]

    Dubrin, James W.

    1985-01-01

    Isotope enrichment, particularly .sup.235 U enrichment, is achieved by irradiating an isotopically mixed vapor feed with radiant energy at a wavelength or wavelengths chosen to selectively excite the species containing a desired isotope to a predetermined energy level. The vapor feed if simultaneously reacted with an atomic or molecular reactant species capable of preferentially transforming the excited species into an ionic product by a chemiionization reaction. The ionic product, enriched in the desired isotope, is electrostatically or electromagnetically extracted from the reaction system.

  2. EIS-0249: Medical Isotopes Production Project

    Broader source: Energy.gov [DOE]

    This EIS evaluates the potential environmental impacts of a proposal to establish a production capability for molybdenum-99 (Mo-99) and related medical isotopes.

  3. Deep-Burn Modular Helium Reactor Fuel Development Plan

    SciTech Connect (OSTI)

    McEachern, D

    2002-12-02

    This document contains the workscope, schedule and cost for the technology development tasks needed to satisfy the fuel and fission product transport Design Data Needs (DDNs) for the Gas Turbine-Modular Helium Reactor (GT-MHR), operating in its role of transmuting transuranic (TRU) nuclides in spent fuel discharged from commercial light-water reactors (LWRs). In its application for transmutation, the GT-MHR is referred to as the Deep-Burn MHR (DB-MHR). This Fuel Development Plan (FDP) describes part of the overall program being undertaken by the U.S. Department of Energy (DOE), utilities, and industry to evaluate the use of the GT-MHR to transmute transuranic nuclides from spent nuclear fuel. The Fuel Development Plan (FDP) includes the work on fuel necessary to support the design and licensing of the DB-MHR. The FDP is organized into ten sections. Section 1 provides a summary of the most important features of the plan, including cost and schedule information. Section 2 describes the DB-MHR concept, the features of its fuel and the plan to develop coated particle fuel for transmutation. Section 3 describes the knowledge base for fabrication of coated particles, the experience with irradiation performance of coated particle fuels, the database for fission product transport in HTGR cores, and describes test data and calculations for the performance of coated particle fuel while in a repository. Section 4 presents the fuel performance requirements in terms of as-manufactured quality and performance of the fuel coatings under irradiation and accident conditions. These requirements are provisional because the design of the DB-MHR is in an early stage. However, the requirements are presented in this preliminary form to guide the initial work on the fuel development. Section 4 also presents limits on the irradiation conditions to which the coated particle fuel can be subjected for the core design. These limits are based on past irradiation experience. Section 5 describes

  4. Uranium isotopes fingerprint biotic reduction

    SciTech Connect (OSTI)

    Stylo, Malgorzata; Neubert, Nadja; Wang, Yuheng; Monga, Nikhil; Romaniello, Stephen J.; Weyer, Stefan; Bernier-Latmani, Rizlan

    2015-04-20

    Knowledge of paleo-redox conditions in the Earth’s history provides a window into events that shaped the evolution of life on our planet. The role of microbial activity in paleo-redox processes remains unexplored due to the inability to discriminate biotic from abiotic redox transformations in the rock record. The ability to deconvolute these two processes would provide a means to identify environmental niches in which microbial activity was prevalent at a specific time in paleo-history and to correlate specific biogeochemical events with the corresponding microbial metabolism. Here, we demonstrate that the isotopic signature associated with microbial reduction of hexavalent uranium (U), i.e., the accumulation of the heavy isotope in the U(IV) phase, is readily distinguishable from that generated by abiotic uranium reduction in laboratory experiments. Thus, isotope signatures preserved in the geologic record through the reductive precipitation of uranium may provide the sought-after tool to probe for biotic processes. Because uranium is a common element in the Earth’s crust and a wide variety of metabolic groups of microorganisms catalyze the biological reduction of U(VI), this tool is applicable to a multiplicity of geological epochs and terrestrial environments. The findings of this study indicate that biological activity contributed to the formation of many authigenic U deposits, including sandstone U deposits of various ages, as well as modern, Cretaceous, and Archean black shales. In addition, engineered bioremediation activities also exhibit a biotic signature, suggesting that, although multiple pathways may be involved in the reduction, direct enzymatic reduction contributes substantially to the immobilization of uranium.

  5. Uranium isotopes fingerprint biotic reduction

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

    Stylo, Malgorzata; Neubert, Nadja; Wang, Yuheng; Monga, Nikhil; Romaniello, Stephen J.; Weyer, Stefan; Bernier-Latmani, Rizlan

    2015-04-20

    Knowledge of paleo-redox conditions in the Earth’s history provides a window into events that shaped the evolution of life on our planet. The role of microbial activity in paleo-redox processes remains unexplored due to the inability to discriminate biotic from abiotic redox transformations in the rock record. The ability to deconvolute these two processes would provide a means to identify environmental niches in which microbial activity was prevalent at a specific time in paleo-history and to correlate specific biogeochemical events with the corresponding microbial metabolism. Here, we demonstrate that the isotopic signature associated with microbial reduction of hexavalent uranium (U),more » i.e., the accumulation of the heavy isotope in the U(IV) phase, is readily distinguishable from that generated by abiotic uranium reduction in laboratory experiments. Thus, isotope signatures preserved in the geologic record through the reductive precipitation of uranium may provide the sought-after tool to probe for biotic processes. Because uranium is a common element in the Earth’s crust and a wide variety of metabolic groups of microorganisms catalyze the biological reduction of U(VI), this tool is applicable to a multiplicity of geological epochs and terrestrial environments. The findings of this study indicate that biological activity contributed to the formation of many authigenic U deposits, including sandstone U deposits of various ages, as well as modern, Cretaceous, and Archean black shales. In addition, engineered bioremediation activities also exhibit a biotic signature, suggesting that, although multiple pathways may be involved in the reduction, direct enzymatic reduction contributes substantially to the immobilization of uranium.« less

  6. Uranium molecular laser isotope separation

    SciTech Connect (OSTI)

    Jensen, R.J.; Sullivan, A.

    1982-01-01

    The Molecular Laser Isotope Separation program is moving into the engineering phase, and it is possible to determine in some detail the plant cost terms involved in the process economics. A brief description of the MLIS process physics is given as a motivation to the engineering and economics discussion. Much of the plant cost arises from lasers and the overall optical system. In the paper, the authors discuss lasers as operating units and systems, along with temporal multiplexing and Raman shifting. Estimates of plant laser costs are given.

  7. Hydrogen-isotope permeation barrier

    DOE Patents [OSTI]

    Maroni, Victor A.; Van Deventer, Erven H.

    1977-01-01

    A composite including a plurality of metal layers has a Cu-Al-Fe bronze layer and at least one outer layer of a heat and corrosion resistant metal alloy. The bronze layer is ordinarily intermediate two outer layers of metal such as austenitic stainless steel, nickel alloys or alloys of the refractory metals. The composite provides a barrier to hydrogen isotopes, particularly tritium that can reduce permeation by at least about 30 fold and possibly more below permeation through equal thicknesses of the outer layer material.

  8. Spatial periphery of lithium isotopes

    SciTech Connect (OSTI)

    Galanina, L. I. Zelenskaja, N. S.

    2013-12-15

    The spatial structure of lithium isotopes is studied with the aid of the charge-exchange and (t, p) reactions on lithium nuclei. It is shown that an excited isobaric-analog state of {sup 6}Li (0{sup +}, 3.56MeV) has a halo structure formed by a proton and a neutron, that, in the {sup 9}Li nucleus, there is virtually no neutron halo, and that {sup 11}Li is a Borromean nucleus formed by a {sup 9}Li core and a two-neutron halo manifesting itself in cigar-like and dineutron configurations.

  9. Ordinary SQUID interferometers and superfluid helium matter wave interferometers: The role of quantum fluctuations

    SciTech Connect (OSTI)

    Golovashkin, A. I.; Zherikhina, L. N. Tskhovrebov, A. M.; Izmailov, G. N.; Ozolin, V. V.

    2010-08-15

    When comparing the operation of a superfluid helium matter wave quantum interferometer (He SQUID) with that of an ordinary direct-current quantum interferometer (dc SQUID), we estimate their resolution limitation that correspond to quantum fluctuations. An alternative mode of operation of the interferometer as a unified macroquantum system is considered.

  10. Simulation of streamers propagating along helium jets in ambient air: Polarity-induced effects

    SciTech Connect (OSTI)

    Naidis, G. V.

    2011-04-04

    Results of modeling of streamer propagation along helium jets for both positive and negative polarities of applied voltage are presented. Obtained patterns of streamer dynamics and structure in these two cases are similar to those observed in experiments with plasma jets.

  11. RECONCILING THE GALACTIC BULGE TURNOFF AGE DISCREPANCY WITH ENHANCED HELIUM ENRICHMENT

    SciTech Connect (OSTI)

    Nataf, David M.; Gould, Andrew P.

    2012-06-01

    We show that the factor {approx}2 discrepancy between spectroscopic and photometric age determinations of the Galactic bulge main-sequence turnoff can be naturally explained by positing an elevated helium enrichment for the bulge relative to that assumed by standard isochrones. Helium enhancement relative to standard isochrones is confirmed at the 2.3{sigma} level. We obtain an upper bound on the helium enrichment for the metal-rich ([Fe/H] Almost-Equal-To +0.30) stars of {Delta}Y Almost-Equal-To +0.11 relative to canonical expectations, given the requirement that the spectroscopic and photometric ages be consistent and the limiting condition of instantaneous star formation. We discuss phenomenological evidence that the bulge may have had a chemical evolution that is distinct from the solar neighborhood in this manner, and we make several testable predictions. Should this emerging picture of the bulge as helium-enhanced hold, it will require the development of new isochrones, new model atmospheres, and modified analysis and cosmological interpretation of the integrated light of other bulges and elliptical galaxies.

  12. Helium, Iron and Electron Particle Transport and Energy Transport Studies on the TFTR Tokamak

    DOE R&D Accomplishments [OSTI]

    Synakowski, E. J.; Efthimion, P. C.; Rewoldt, G.; Stratton, B. C.; Tang, W. M.; Grek, B.; Hill, K. W.; Hulse, R. A.; Johnson, D .W.; Mansfield, D. K.; McCune, D.; Mikkelsen, D. R.; Park, H. K.; Ramsey, A. T.; Redi, M. H.; Scott, S. D.; Taylor, G.; Timberlake, J.; Zarnstorff, M. C. (Princeton Univ., NJ (United States). Plasma Physics Lab.); Kissick, M. W. (Wisconsin Univ., Madison, WI (United States))

    1993-03-01

    Results from helium, iron, and electron transport on TFTR in L-mode and Supershot deuterium plasmas with the same toroidal field, plasma current, and neutral beam heating power are presented. They are compared to results from thermal transport analysis based on power balance. Particle diffusivities and thermal conductivities are radially hollow and larger than neoclassical values, except possibly near the magnetic axis. The ion channel dominates over the electron channel in both particle and thermal diffusion. A peaked helium profile, supported by inward convection that is stronger than predicted by neoclassical theory, is measured in the Supershot The helium profile shape is consistent with predictions from quasilinear electrostatic drift-wave theory. While the perturbative particle diffusion coefficients of all three species are similar in the Supershot, differences are found in the L-Mode. Quasilinear theory calculations of the ratios of impurity diffusivities are in good accord with measurements. Theory estimates indicate that the ion heat flux should be larger than the electron heat flux, consistent with power balance analysis. However, theoretical values of the ratio of the ion to electron heat flux can be more than a factor of three larger than experimental values. A correlation between helium diffusion and ion thermal transport is observed and has favorable implications for sustained ignition of a tokamak fusion reactor.

  13. Non-local thermodynamic equilibrium effects on isentropic coefficient in argon and helium thermal plasmas

    SciTech Connect (OSTI)

    Sharma, Rohit; Singh, Kuldip

    2014-03-15

    In the present work, two cases of thermal plasma have been considered; the ground state plasma in which all the atoms and ions are assumed to be in the ground state and the excited state plasma in which atoms and ions are distributed over various possible excited states. The variation of Z?, frozen isentropic coefficient and the isentropic coefficient with degree of ionization and non-equilibrium parameter ?(= T{sub e}/T{sub h}) has been investigated for the ground and excited state helium and argon plasmas at pressures 1?atm, 10?atm, and 100?atm in the temperature range from 6000?K to 60?000?K. For a given value of non-equilibrium parameter, the relationship of Z? with degree of ionization does not show any dependence on electronically excited states in helium plasma whereas in case of argon plasma this dependence is not appreciable till degree of ionization approaches 2. The minima of frozen isentropic coefficient shifts toward lower temperature with increase of non-equilibrium parameter for both the helium and argon plasmas. The lowering of non-equilibrium parameter decreases the frozen isentropic coefficient more emphatically in helium plasma at high pressures in comparison to argon plasma. The increase of pressure slightly reduces the ionization range over which isentropic coefficient almost remains constant and it does not affect appreciably the dependence of isentropic coefficient on non-equilibrium parameter.

  14. Helium bubble formation in ultrafine and nanocrystalline tungsten under different extreme conditions

    SciTech Connect (OSTI)

    El-atwani, O.; Hattar, Khalid Mikhiel; Hinks, J. A.; Greaves, G.; Harilal, S. S.; Hassanein, A.

    2014-12-25

    We investigated the effects of helium ion irradiation energy and sample temperature on the performance of grain boundaries as helium sinks in ultrafine grained and nanocrystalline tungsten. Irradiations were performed at displacement and non-displacement energies and at temperatures above and below that required for vacancy migration. Microstructural investigations were performed using Transmission Electron Microscopy (TEM) combined with either in-situ or ex-situ ion irradiation. Under helium irradiation at an energy which does not cause atomic displacements in tungsten (70 eV), regardless of temperature and thus vacancy migration conditions, bubbles were uniformly distributed with no preferential bubble formation on grain boundaries. Moreover, at energies that can cause displacements, bubbles were observed to be preferentially formed on the grain boundaries only at high temperatures where vacancy migration occurs. Under these conditions, the decoration of grain boundaries with large facetted bubbles occurred on nanocrystalline grains with dimensions less than 60 nm. Finally, we discuss the importance of vacancy supply and the formation and migration of radiation-induced defects on the performance of grain boundaries as helium sinks and the resulting irradiation tolerance of ultrafine grained and nanocrystalline tungsten to bubble formation.

  15. Helium bubble formation in ultrafine and nanocrystalline tungsten under different extreme conditions

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

    El-atwani, O.; Hattar, Khalid Mikhiel; Hinks, J. A.; Greaves, G.; Harilal, S. S.; Hassanein, A.

    2014-12-25

    We investigated the effects of helium ion irradiation energy and sample temperature on the performance of grain boundaries as helium sinks in ultrafine grained and nanocrystalline tungsten. Irradiations were performed at displacement and non-displacement energies and at temperatures above and below that required for vacancy migration. Microstructural investigations were performed using Transmission Electron Microscopy (TEM) combined with either in-situ or ex-situ ion irradiation. Under helium irradiation at an energy which does not cause atomic displacements in tungsten (70 eV), regardless of temperature and thus vacancy migration conditions, bubbles were uniformly distributed with no preferential bubble formation on grain boundaries. Moreover,more » at energies that can cause displacements, bubbles were observed to be preferentially formed on the grain boundaries only at high temperatures where vacancy migration occurs. Under these conditions, the decoration of grain boundaries with large facetted bubbles occurred on nanocrystalline grains with dimensions less than 60 nm. Finally, we discuss the importance of vacancy supply and the formation and migration of radiation-induced defects on the performance of grain boundaries as helium sinks and the resulting irradiation tolerance of ultrafine grained and nanocrystalline tungsten to bubble formation.« less

  16. Statistical Properties of Inter-Series Mixing in Helium: From Integrability to Chaos

    SciTech Connect (OSTI)

    Pu''ttner, R.; Gremaud, B.; Delande, D.; Domke, M.; Martins, M.; Schlachter, A. S.; Kaindl, G.

    2001-04-23

    The photoionization spectrum of helium shows considerable complexity close to the double-ionization threshold. By analyzing the results from both our recent experiments and ab initio three- and one-dimensional calculations, we show that the statistical properties of the spacings between neighboring energy levels clearly display a transition towards quantum chaos.

  17. Maximum Reasonable Radioxenon Releases from Medical Isotope Production Facilities and Their Effect on Monitoring Nuclear Explosions

    SciTech Connect (OSTI)

    Bowyer, Ted W.; Kephart, Rosara F.; Eslinger, Paul W.; Friese, Judah I.; Miley, Harry S.; Saey, Paul R.

    2013-01-01

    Fission gases such as 133Xe are used extensively for monitoring the world for signs of nuclear testing in systems such as the International Monitoring System (IMS). These gases are also produced by nuclear reactors and by fission production of 99Mo for medical use. Recently, medical isotope production facilities have been identified as the major contributor to the background of radioactive xenon isotopes (radioxenon) in the atmosphere (Saey, et al., 2009). These releases pose a potential future problem for monitoring nuclear explosions if not addressed. As a starting point, a maximum acceptable daily xenon emission rate was calculated, that is both scientifically defendable as not adversely affecting the IMS, but also consistent with what is possible to achieve in an operational environment. This study concludes that an emission of 5×109 Bq/day from a medical isotope production facility would be both an acceptable upper limit from the perspective of minimal impact to monitoring stations, but also appears to be an achievable limit for large isotope producers.

  18. Sustainable Nanomaterials from Forest Products: Umaine Perspective...

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

    Sustainable Nanomaterials from Forest Products: Umaine Perspective Sustainable Nanomaterials from Forest Products: Umaine Perspective Sustainable Nanomaterials from Forest Products ...

  19. NNSA Procurement Projects Perspective - Bob Raines, Associate...

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

    Projects Perspective - Bob Raines, Associate Administrator for Acquisition and Project Management, NNSA NNSA Procurement Projects Perspective - Bob Raines, Associate Administrator ...

  20. Efficient palladium isotope chromatograph for hydrogen (EPIC)

    SciTech Connect (OSTI)

    Embury, M.C.; Ellefson, R.E.; Melke, H.B. )

    1992-03-01

    The Efficient Palladium Isotope Chromatograph (EPIC) is a rapid cycling, computer-operated displacement chromatograph for the separation of hydrogen isotopes. EPIC incorporates several features that optimize product throughput and purity. This paper describes this palladium displacement chromatograph, the operations with protium and deuterium, and the design modifications for operation with tritium.

  1. Isotope separation by selective photodissociation of glyoxal

    DOE Patents [OSTI]

    Marling, John B.

    1976-01-01

    Dissociation products, mainly formaldehyde and carbon monoxide, enriched in a desired isotope of carbon, oxygen, or hydrogen are obtained by the selective photodissociation of glyoxal wherein glyoxal is subjected to electromagnetic radiation of a predetermined wavelength such that photon absorption excites and induces dissociation of only those molecules of glyoxal containing the desired isotope.

  2. Isotope mass spectrometry from 1968 to 1989

    SciTech Connect (OSTI)

    DeBievre, P. )

    1989-11-01

    The principal developments in isotope mass spectrometry are described with respect to instrument construction, detector technology, measurement precision, measurement accuracy, and reference materials. The increase in the application of isotope mass spectrometry is summarized, with special emphasis on its use in safeguards of nuclear materials. The future potential versus the present achievements of the field are discussed.

  3. Advanced Mass Spectrometers for Hydrogen Isotope Analyses

    SciTech Connect (OSTI)

    Chastagner, P.

    2001-08-01

    This report is a summary of the results of a joint Savannah River Laboratory (SRL) - Savannah River Plant (SRP) ''Hydrogen Isotope Mass Spectrometer Evaluation Program''. The program was undertaken to evaluate two prototype hydrogen isotope mass spectrometers and obtain sufficient data to permit SRP personnel to specify the mass spectrometers to replace obsolete instruments.

  4. Thermal analysis of a coaxial helium panel of a cryogenic vacuum pump for advanced divertor of DIII-D tokamak

    SciTech Connect (OSTI)

    Baxi, C.B.; Langhorn, A.; Schaubel, K.; Smith, J.

    1991-08-01

    It is planned to install a 50,000 1/s cryogenic pump for particle removal in the D3-D tokamak. A critical component of this cryogenic pump will be a helium panel which has to be maintained at a liquid helium temperature. The outer surface area of the helium panel has an area of 1 m{sup 2} and consists of a 2.5 cm diameter, 10 m long tube. From design considerations, a coaxial geometry is preferable since it requires a minimum number of welds. However, the coaxial geometry also results in a counter flow heat exchanger arrangement, where the outgoing warm fluid will exchange heat with incoming cold fluid. This is of concern since the helium panel must be cooled from liquid nitrogen temperature to liquid helium temperature in less than 5 minutes for successful operation of the cryogenic pump. In order to analyze the thermal performance of the coaxial helium panel, a finite difference computer model of the geometry was prepared. The governing equations took into account axial as well as radial conduction through the tube walls. The variation of thermal properties was modeled. The results of the analysis showed that although the coaxial geometry behaves like a counter flow heat exchanger, within the operating range of the cryogenic pump a rapid cooldown of the helium panel from liquid nitrogen temperature to the operating temperature is feasible. A prototypical experiment was also performed at General Atomics (GA) which verified the concept and the analysis. 4 refs., 8 figs.

  5. Plutonium Isotopes in the Terrestrial Environment at the Savannah...

    Office of Scientific and Technical Information (OSTI)

    Plutonium Isotopes in the Terrestrial Environment at the Savannah River Site, USA. A Long-Term Study Citation Details In-Document Search Title: Plutonium Isotopes in the ...

  6. Advances in Hydrogen Isotope Separation Using Thermal Cycling...

    Office of Environmental Management (EM)

    Hydrogen Isotope Separation Using Thermal Cycling Absorption Process (TCAP) Advances in Hydrogen Isotope Separation Using Thermal Cycling Absorption Process (TCAP) Presentation ...

  7. Manus Water Isotope Investigation Field Campaign Report (Program...

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Search Results Program Document: Manus Water Isotope Investigation Field Campaign Report Citation Details In-Document Search Title: Manus Water Isotope ...

  8. Review of hydrogen isotope permeability through materials (Technical...

    Office of Scientific and Technical Information (OSTI)

    Review of hydrogen isotope permeability through materials Citation Details In-Document Search Title: Review of hydrogen isotope permeability through materials You are accessing ...

  9. Expert Panel: Forecast Future Demand for Medical Isotopes | Department...

    Office of Environmental Management (EM)

    Though the cost of providing a reliable and diverse supply of isotopes for medical use may ... More Documents & Publications Final Report, NEAC Subcommittee for Isotope Research & ...

  10. Isotopic Analysis At Fenton Hill Hdr Geothermal Area (Goff, Et...

    Open Energy Info (EERE)

    Isotopic Analysis At Fenton Hill Hdr Geothermal Area (Goff, Et Al., 1981) Redirect page Jump to: navigation, search REDIRECT Isotopic Analysis- Fluid At Fenton Hill Hdr Geothermal...

  11. Device and method for separating oxygen isotopes

    DOE Patents [OSTI]

    Rockwood, Stephen D.; Sander, Robert K.

    1984-01-01

    A device and method for separating oxygen isotopes with an ArF laser which produces coherent radiation at approximately 193 nm. The output of the ArF laser is filtered in natural air and applied to an irradiation cell where it preferentially photodissociates molecules of oxygen gas containing .sup.17 O or .sup.18 O oxygen nuclides. A scavenger such as O.sub.2, CO or ethylene is used to collect the preferentially dissociated oxygen atoms and recycled to produce isotopically enriched molecular oxygen gas. Other embodiments utilize an ArF laser which is narrowly tuned with a prism or diffraction grating to preferentially photodissociate desired isotopes. Similarly, desired mixtures of isotopic gas can be used as a filter to photodissociate enriched preselected isotopes of oxygen.

  12. Selected Isotopes for Optimized Fuel Assembly Tags

    SciTech Connect (OSTI)

    Gerlach, David C.; Mitchell, Mark R.; Reid, Bruce D.; Gesh, Christopher J.; Hurley, David E.

    2008-10-01

    In support of our ongoing signatures project we present information on 3 isotopes selected for possible application in optimized tags that could be applied to fuel assemblies to provide an objective measure of burnup. 1. Important factors for an optimized tag are compatibility with the reactor environment (corrosion resistance), low radioactive activation, at least 2 stable isotopes, moderate neutron absorption cross-section, which gives significant changes in isotope ratios over typical fuel assembly irradiation levels, and ease of measurement in the SIMS machine 2. From the candidate isotopes presented in the 3rd FY 08 Quarterly Report, the most promising appear to be Titanium, Hafnium, and Platinum. The other candidate isotopes (Iron, Tungsten, exhibited inadequate corrosion resistance and/or had neutron capture cross-sections either too high or too low for the burnup range of interest.

  13. Atomic vapor laser isotope separation of lead-210 isotope

    DOE Patents [OSTI]

    Scheibner, Karl F.; Haynam, Christopher A.; Johnson, Michael A.; Worden, Earl F.

    1999-01-01

    An isotopically selective laser process and apparatus for removal of Pb-210 from natural lead that involves a one-photon near-resonant, two-photon resonant excitation of one or more Rydberg levels, followed by field ionization and then electrostatic extraction. The wavelength to the near-resonant intermediate state is counter propagated with respect to the second wavelength required to populate the final Rydberg state. This scheme takes advantage of the large first excited state cross section, and only modest laser fluences are required. The non-resonant process helps to avoid two problems: first, stimulated Raman Gain due to the nearby F=3/2 hyperfine component of Pb-207 and, second, direct absorption of the first transition process light by Pb-207.

  14. Atomic vapor laser isotope separation of lead-210 isotope

    DOE Patents [OSTI]

    Scheibner, K.F.; Haynam, C.A.; Johnson, M.A.; Worden, E.F.

    1999-08-31

    An isotopically selective laser process and apparatus for removal of Pb-210 from natural lead that involves a one-photon near-resonant, two-photon resonant excitation of one or more Rydberg levels, followed by field ionization and then electrostatic extraction. The wavelength to the near-resonant intermediate state is counter propagated with respect to the second wavelength required to populate the final Rydberg state. This scheme takes advantage of the large first excited state cross section, and only modest laser fluences are required. The non-resonant process helps to avoid two problems: first, stimulated Raman Gain due to the nearby F=3/2 hyperfine component of Pb-207 and, second, direct absorption of the first transition process light by Pb-207. 5 figs.

  15. Atomic vapor laser isotope separation

    SciTech Connect (OSTI)

    Stern, R.C.; Paisner, J.A.

    1985-11-08

    Atomic vapor laser isotope separation (AVLIS) is a general and powerful technique. A major present application to the enrichment of uranium for light-water power reactor fuel has been under development for over 10 years. In June 1985 the Department of Energy announced the selection of AVLIS as the technology to meet the nation's future need for the internationally competitive production of uranium separative work. The economic basis for this decision is considered, with an indicated of the constraints placed on the process figures of merit and the process laser system. We then trace an atom through a generic AVLIS separator and give examples of the physical steps encountered, the models used to describe the process physics, the fundamental parameters involved, and the role of diagnostic laser measurements.

  16. Apparatus for storing hydrogen isotopes

    DOE Patents [OSTI]

    McMullen, John W.; Wheeler, Michael G.; Cullingford, Hatice S.; Sherman, Robert H.

    1985-01-01

    An improved method and apparatus for storing isotopes of hydrogen (especially tritium) are provided. The hydrogen gas(es) is (are) stored as hydrides of material (for example uranium) within boreholes in a block of copper. The mass of the block is critically important to the operation, as is the selection of copper, because no cooling pipes are used. Because no cooling pipes are used, there can be no failure due to cooling pipes. And because copper is used instead of stainless steel, a significantly higher temperature can be reached before the eutectic formation of uranium with copper occurs, (the eutectic of uranium with the iron in stainless steel forming at a significantly lower temperature).

  17. WARM BREEZE FROM THE STARBOARD BOW: A NEW POPULATION OF NEUTRAL HELIUM IN THE HELIOSPHERE

    SciTech Connect (OSTI)

    Kubiak, M. A.; Bzowski, M.; Sokół, J. M.; Swaczyna, P.; Grzedzielski, S.; Alexashov, D. B.; Izmodenov, V. V.; Möbius, E.; Leonard, T.; Fuselier, S. A.; McComas, D. J.; Wurz, P.

    2014-08-01

    We investigate the signals from neutral helium atoms observed in situ from Earth orbit in 2010 by the Interstellar Boundary Explorer (IBEX). The full helium signal observed during the 2010 observation season can be explained as a superposition of pristine neutral interstellar He gas and an additional population of neutral helium that we call the Warm Breeze. The Warm Breeze is approximately 2 times slower and 2.5 times warmer than the primary interstellar He population, and its density in front of the heliosphere is ∼7% that of the neutral interstellar helium. The inflow direction of the Warm Breeze differs by ∼19° from the inflow direction of interstellar gas. The Warm Breeze seems to be a long-term, perhaps permanent feature of the heliospheric environment. It has not been detected earlier because it is strongly ionized inside the heliosphere. This effect brings it below the threshold of detection via pickup ion and heliospheric backscatter glow observations, as well as by the direct sampling of GAS/Ulysses. We discuss possible sources for the Warm Breeze, including (1) the secondary population of interstellar helium, created via charge exchange and perhaps elastic scattering of neutral interstellar He atoms on interstellar He{sup +} ions in the outer heliosheath, or (2) a gust of interstellar He originating from a hypothetic wave train in the Local Interstellar Cloud. A secondary population is expected from models, but the characteristics of the Warm Breeze do not fully conform to modeling results. If, nevertheless, this is the explanation, IBEX-Lo observations of the Warm Breeze provide key insights into the physical state of plasma in the outer heliosheath. If the second hypothesis is true, the source is likely to be located within a few thousand AU from the Sun, which is the propagation range of possible gusts of interstellar neutral helium with the Warm Breeze characteristics against dissipation via elastic scattering in the Local Cloud. Whatever the

  18. Isotope separation by photoselective dissociative electron capture

    DOE Patents [OSTI]

    Stevens, C.G.

    1978-08-29

    Disclosed is a method of separating isotopes based on photoselective electron capture dissociation of molecules having an electron capture cross section dependence on the vibrational state of the molecule. A molecular isotope source material is irradiated to selectively excite those molecules containing a desired isotope to a predetermined vibrational state having associated therewith an electron capture energy region substantially non-overlapping with the electron capture energy ranges associated with the lowest vibration states of the molecules. The isotope source is also subjected to electrons having an energy corresponding to the non-overlapping electron capture region whereby the selectively excited molecules preferentially capture electrons and dissociate into negative ions and neutrals. The desired isotope may be in the negative ion product or in the neutral product depending upon the mechanism of dissociation of the particular isotope source used. The dissociation product enriched in the desired isotope is then separated from the reaction system by conventional means. Specifically, [sup 235]UF[sub 6] is separated from a UF[sub 6] mixture by selective excitation followed by dissociative electron capture into [sup 235]UF[sub 5]- and F. 2 figs.

  19. Isotope separation by photoselective dissociative electron capture

    DOE Patents [OSTI]

    Stevens, Charles G. [Pleasanton, CA

    1978-08-29

    A method of separating isotopes based on photoselective electron capture dissociation of molecules having an electron capture cross section dependence on the vibrational state of the molecule. A molecular isotope source material is irradiated to selectively excite those molecules containing a desired isotope to a predetermined vibrational state having associated therewith an electron capture energy region substantially non-overlapping with the electron capture energy ranges associated with the lowest vibration states of the molecules. The isotope source is also subjected to electrons having an energy corresponding to the non-overlapping electron capture region whereby the selectively excited molecules preferentially capture electrons and dissociate into negative ions and neutrals. The desired isotope may be in the negative ion product or in the neutral product depending upon the mechanism of dissociation of the particular isotope source used. The dissociation product enriched in the desired isotope is then separated from the reaction system by conventional means. Specifically, .sup.235 UF.sub.6 is separated from a UF.sub.6 mixture by selective excitation followed by dissociative electron capture into .sup.235 UF.sub.5 - and F.

  20. The effect of helium from tritium decay on the gas-solid equilibrium constant for La-Ni-Al tritides

    SciTech Connect (OSTI)

    Walters, R.T.

    1988-01-01

    Change in the equilibrium vapor pressure over LaNi/sub 4.25/ Al/sub 0.75/ tritide with helium in-growth has been observed for helium concentrations up to 10,000 appm. The change is a decrease in pressure from about 500 torr to 90 torr at 80/degree/C. This decrease is believed to be associated with a crystal lattice expansion due to helium, and is similar to the plateau pressure decrease as function of aluminum concentration for the family of LaNi/sub 5-x/Al/sub x/ alloys with O < x < 1. Subsequent tritium cycling recovers the plateau pressure. These data suggest that helium has very short range diffusion for the time of these observations. 18 refs., 4 figs., 2 tabs.

  1. Isotope effects on desorption kinetics of hydrogen isotopes implanted into stainless steel by glow discharge

    SciTech Connect (OSTI)

    Matsuyama, M.; Kondo, M.; Noda, N.; Tanaka, M.; Nishimura, K.

    2015-03-15

    In a fusion device the control of fuel particles implies to know the desorption rate of hydrogen isotopes by the plasma-facing materials. In this paper desorption kinetics of hydrogen isotopes implanted into type 316L stainless steel by glow discharge have been studied by experiment and numerical calculation. The temperature of a maximum desorption rate depends on glow discharge time and heating rate. Desorption spectra observed under various experimental conditions have been successfully reproduced by numerical simulations that are based on a diffusion-limited process. It is suggested, therefore, that desorption rate of a hydrogen isotope implanted into the stainless steel is limited by a diffusion process of hydrogen isotope atoms in bulk. Furthermore, small isotope effects were observed for the diffusion process of hydrogen isotope atoms. (authors)

  2. The role of correlation in the ground state energy of confined helium atom

    SciTech Connect (OSTI)

    Aquino, N.

    2014-01-14

    We analyze the ground state energy of helium atom confined by spherical impenetrable walls, and the role of the correlation energy in the total energy. The confinement of an atom in a cavity is one way in which we can model the effect of the external pressure on an atom. The calculations of energy of the system are carried out by the variational method. We find that the correlation energy remains almost constant for a range values of size of the boxes analyzed.

  3. Final Technical Report for the Neutron Detection without Helium-3 Project

    SciTech Connect (OSTI)

    Ely, James H.; Bliss, Mary; Kouzes, Richard T.; Lintereur, Azaree T.; Robinson, Sean M.; Siciliano, Edward R.; Swinhoe, Martyn T.; Woodring, Mitchell L.

    2013-11-01

    This report details the results of the research and development work accomplished for the ‘Neutron Detection without Helium-3’ project conducted during the 2011-2013 fiscal years. The primary focus of the project was to investigate commercially available technologies that might be used in safeguards applications in the relatively near term. Other technologies that are being developed may be more applicable in the future, but were outside the scope of this study.

  4. Modeling and Simulation Optimization and Feasibility Studies for the Neutron Detection without Helium-3 Project

    SciTech Connect (OSTI)

    Ely, James H.; Siciliano, Edward R.; Swinhoe, Martyn T.; Lintereur, Azaree T.

    2013-01-01

    This report details the results of the modeling and simulation work accomplished for the ‘Neutron Detection without Helium-3’ project during the 2011 and 2012 fiscal years. The primary focus of the project is to investigate commercially available technologies that might be used in safeguards applications in the relatively near term. Other technologies that are being developed may be more applicable in the future, but are outside the scope of this study.

  5. Double, Double Toil and Trouble: Tungsten Burns and Helium Bubbles | U.S.

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

    DOE Office of Science (SC) Double, Double Toil and Trouble: Tungsten Burns and Helium Bubbles Advanced Scientific Computing Research (ASCR) ASCR Home About Research Facilities Science Highlights Benefits of ASCR Funding Opportunities Advanced Scientific Computing Advisory Committee (ASCAC) Community Resources Contact Information Advanced Scientific Computing Research U.S. Department of Energy SC-21/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-7486 F: (301)

  6. Radiation and gas conduction heat transport across a helium dewer multilayer insulation system

    SciTech Connect (OSTI)

    Green, M.A.

    1995-02-01

    This report describes a method for calculating mixed heat transfer through the multilayer insulation used to insulated a 4K liquid helium cryostat. The method described permits one to estimate the insulation potential for a multilayer insulation system from first principles. The heat transfer regimes included are: radiation, conduction by free molecule gas conduction, and conduction through continuum gas conduction. Heat transfer in the transition region between the two gas conduction regimes is also included.

  7. Measurements of the volt-ampere characteristics and the breakdown voltages of direct-current helium and hydrogen discharges in microgaps

    SciTech Connect (OSTI)

    Klas, M.; Matej?ik, .; Radjenovi?, B.; Radmilovi?-Radjenovi?, M.

    2014-10-15

    The discharge phenomena for micro meter gap sizes include many interesting problems from engineering and physical perspectives. In this paper, the authors deal with the experimental and theoretical results of the breakdown voltage and current-voltage characteristics of the direct-current helium and hydrogen discharges. The measurements were performed at a constant pressure of around one atmosphere, while varying the gap size between two parallel plane tungsten electrodes between 1??m and 100??m. From the measured breakdown voltage curves, the effective yields and the ionization coefficients were derived for both gases. Present data for the ionization coefficients correlate with the data obtained for the breakdown voltage curves measured for fixed 100??m interelectrode separation. The current-voltage characteristics were plotted for the various gap sizes illustrating the role of the field emission effects in the microgaps. Based on the Fowler-Nordheim theory, the enhancement factors were determined. The gap spacing dependence of the field emission current can be explained by the introduction of two ideas, the first being a space charge effect by emitted electrons, and the second a change in the breakdown mechanism. Experimental results, presented here, demonstrate that Townsend phenomenology breaks down when field emission becomes the key mechanism affecting the breakdown and deforming the left hand side of the breakdown voltage curves.

  8. Investigation of helium ion production in constricted direct current plasma ion source with layered-glows

    SciTech Connect (OSTI)

    Lee, Yuna; Chung, Kyoung-Jae; Park, Yeong-Shin; Hwang, Y. S.; Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744

    2014-02-15

    Generation of helium ions is experimentally investigated with a constricted direct current (DC) plasma ion source operated at layered-glow mode, in which electrons could be accelerated through multiple potential structures so as to generate helium ions including He{sup 2+} by successive ionization collisions in front of an extraction aperture. The helium discharge is sustained with the formation of a couple of stable layers and the plasma ball with high density is created near the extraction aperture at the operational pressure down to 0.6 Torr with concave cathodes. The ion beam current extracted with an extraction voltage of 5 kV is observed to be proportional to the discharge current and inversely proportional to the operating pressure, showing high current density of 130 mA/cm{sup 2} and power density of 0.52 mA/cm{sup 2}/W. He{sup 2+} ions, which were predicted to be able to exist due to multiple-layer potential structure, are not observed. Simple calculation on production of He{sup 2+} ions inside the plasma ball reveals that reduced operating pressure and increased cathode area will help to generate He{sup 2+} ions with the layered-glow DC discharge.

  9. Improvements of fuel failure detection in boiling water reactors using helium measurements

    SciTech Connect (OSTI)

    Larsson, I.; Sihver, L.; Grundin, A.; Helmersson, J. O.

    2012-07-01

    To certify a continuous and safe operation of a boiling water reactor, careful surveillance of fuel integrity is of high importance. The detection of fuel failures can be performed by off-line gamma spectroscopy of off-gas samples and/or by on-line nuclide specific monitoring of gamma emitting noble gases. To establish the location of a leaking fuel rod, power suppression testing can be used. The accuracy of power suppression testing is dependent on the information of the delay time and the spreading of the released fission gases through the systems before reaching the sampling point. This paper presents a method to improve the accuracy of power suppression testing by determining the delay time and gas spreading profile. To estimate the delay time and examine the spreading of the gas in case of a fuel failure, helium was injected in the feed water system at Forsmark 3 nuclear power plant. The measurements were performed by using a helium detector system based on a mass spectrometer installed in the off-gas system. The helium detection system and the results of the experiment are presented in this paper. (authors)

  10. Benchmarking density functionals for hydrogen-helium mixtures with quantum Monte Carlo: Energetics, pressures, and forces

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

    Clay, Raymond C.; Holzmann, Markus; Ceperley, David M.; Morales, Maguel A.

    2016-01-19

    An accurate understanding of the phase diagram of dense hydrogen and helium mixtures is a crucial component in the construction of accurate models of Jupiter, Saturn, and Jovian extrasolar planets. Though DFT based rst principles methods have the potential to provide the accuracy and computational e ciency required for this task, recent benchmarking in hydrogen has shown that achieving this accuracy requires a judicious choice of functional, and a quanti cation of the errors introduced. In this work, we present a quantum Monte Carlo based benchmarking study of a wide range of density functionals for use in hydrogen-helium mixtures atmore » thermodynamic conditions relevant for Jovian planets. Not only do we continue our program of benchmarking energetics and pressures, but we deploy QMC based force estimators and use them to gain insights into how well the local liquid structure is captured by di erent density functionals. We nd that TPSS, BLYP and vdW-DF are the most accurate functionals by most metrics, and that the enthalpy, energy, and pressure errors are very well behaved as a function of helium concentration. Beyond this, we highlight and analyze the major error trends and relative di erences exhibited by the major classes of functionals, and estimate the magnitudes of these e ects when possible.« less

  11. Coupling a Supercritical Carbon Dioxide Brayton Cycle to a Helium-Cooled Reactor.

    SciTech Connect (OSTI)

    Middleton, Bobby; Pasch, James Jay; Kruizenga, Alan Michael; Walker, Matthew

    2016-01-01

    This report outlines the thermodynamics of a supercritical carbon dioxide (sCO2) recompression closed Brayton cycle (RCBC) coupled to a Helium-cooled nuclear reactor. The baseline reactor design for the study is the AREVA High Temperature Gas-Cooled Reactor (HTGR). Using the AREVA HTGR nominal operating parameters, an initial thermodynamic study was performed using Sandia's deterministic RCBC analysis program. Utilizing the output of the RCBC thermodynamic analysis, preliminary values of reactor power and of Helium flow rate through the reactor were calculated in Sandia's HelCO2 code. Some research regarding materials requirements was then conducted to determine aspects of corrosion related to both Helium and to sCO2 , as well as some mechanical considerations for pressures and temperatures that will be seen by the piping and other components. This analysis resulted in a list of materials-related research items that need to be conducted in the future. A short assessment of dry heat rejection advantages of sCO2> Brayton cycles was also included. This assessment lists some items that should be investigated in the future to better understand how sCO2 Brayton cycles and nuclear can maximally contribute to optimizing the water efficiency of carbon free power generation

  12. Design guidelines for avoiding thermo-acoustic oscillations in helium piping systems

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

    Gupta, Prabhat Kumar; Rabehl, Roger

    2015-04-02

    Thermo-acoustic oscillations are a commonly observed phenomenon in helium cryogenic systems, especially in tubes connecting hot and cold areas. The open ends of these tubes are connected to the lower temperature (typically at 4.5 K), and the closed ends of these tubes are connected to the high temperature (300 K). Cryogenic instrumentation installations provide ideal conditions for these oscillations to occur due to the steep temperature gradient along the tubing. These oscillations create errors in measurements as well as an undesirable heat load to the system. The work presented here develops engineering guidelines to design oscillation-free helium piping. This workmore » also studies the effect of different piping inserts and shows how the proper geometrical combinations have to be chosen to avoid thermo-acoustic oscillations. The effect of an 80 K intercept is also studied and shows that thermo-oscillations can be dampened by placing the intercept at an appropriate location. As a result, the design of helium piping based on the present work is also verified with the experimental results available in open literature.« less

  13. Comparison between a propane-air combustion front and a helium-air simulated combustion front

    SciTech Connect (OSTI)

    Barraclough, S.

    1983-12-01

    Turbulent combustion experiments were performed in a right cylindrical combustion bomb using a premixed propane-air gaseous fuel. The initial conditions inside the combustion chamber were three psig and room temperature. Prior to spark firing, the turbulence intensity inside the combustion chamber was measured and could be varied over a ten fold range. The effect of initial turbulence intensity on turbulent flame propagation was investigated. Two regimes of turbulent combustion were identified, which is in agreement with a previous investigator's results. One of them, a ''transition regime'' occurs when the turbulence intensity is approximately twice the laminar flame speed. Within the transition regime, the turbulent burning speed is linearly proportional to initial turbulence intensity and independent of laminar flame speed and turbulence length scale. A high pressure helium front was injected into the combustion chamber to simulate the combustion front. Since the helium front is isothermal, hot-wire anemometry can be used to quantify the change in turbulence intensity ahead of the propagating front. The helium front was found to have different characteristics than the combustion front.

  14. Design guidelines for avoiding thermo-acoustic oscillations in helium piping systems

    SciTech Connect (OSTI)

    Gupta, Prabhat Kumar; Rabehl, Roger

    2015-04-02

    Thermo-acoustic oscillations are a commonly observed phenomenon in helium cryogenic systems, especially in tubes connecting hot and cold areas. The open ends of these tubes are connected to the lower temperature (typically at 4.5 K), and the closed ends of these tubes are connected to the high temperature (300 K). Cryogenic instrumentation installations provide ideal conditions for these oscillations to occur due to the steep temperature gradient along the tubing. These oscillations create errors in measurements as well as an undesirable heat load to the system. The work presented here develops engineering guidelines to design oscillation-free helium piping. This work also studies the effect of different piping inserts and shows how the proper geometrical combinations have to be chosen to avoid thermo-acoustic oscillations. The effect of an 80 K intercept is also studied and shows that thermo-oscillations can be dampened by placing the intercept at an appropriate location. As a result, the design of helium piping based on the present work is also verified with the experimental results available in open literature.

  15. Design guidelines for avoiding thermo-acoustic oscillations in helium piping systems

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

    Gupta, Prabhat Kumar; Rabehl, Roger

    2015-04-02

    Thermo-acoustic oscillations are a commonly observed phenomenon in helium cryogenic systems, especially in tubes connecting hot and cold areas. The open ends of these tubes are connected to the lower temperature (typically at 4.5 K), and the closed ends of these tubes are connected to the high temperature (300 K). Cryogenic instrumentation installations provide ideal conditions for these oscillations to occur due to the steep temperature gradient along the tubing. These oscillations create errors in measurements as well as an undesirable heat load to the system. The work presented here develops engineering guidelines to design oscillation-free helium piping. This workmorealso studies the effect of different piping inserts and shows how the proper geometrical combinations have to be chosen to avoid thermo-acoustic oscillations. The effect of an 80 K intercept is also studied and shows that thermo-oscillations can be dampened by placing the intercept at an appropriate location. As a result, the design of helium piping based on the present work is also verified with the experimental results available in open literature.less

  16. A MEASUREMENT OF THE ADIABATIC COOLING INDEX FOR INTERSTELLAR HELIUM PICKUP IONS IN THE INNER HELIOSPHERE

    SciTech Connect (OSTI)

    Saul, Lukas; Wurz, Peter; Kallenbach, Reinald

    2009-09-20

    Interstellar neutral gas enters the inner heliosphere where it is ionized and becomes the pickup ion population of the solar wind. It is often assumed that this population will subsequently cool adiabatically, like an expanding ideal gas due, to the divergent flow of the solar wind. Here, we report the first independent measure of the effective adiabatic cooling index in the inner heliosphere from SOHO CELIAS measurements of singly charged helium taken during times of perpendicular interplanetary magnetic field. We use a simple adiabatic transport model of interstellar pickup helium ions, valid for the upwind region of the inner heliosphere. The time averaged velocity spectrum of helium pickup ions measured by CELIAS/CTOF is fit to this model with a single free parameter which indicates an effective cooling rate with a power-law index of gamma = 1.35 +- 0.2. While this average is consistent with the 'ideal-gas' assumption of gamma = 1.5, the analysis indicates that such an assumption will not apply in general, and that due to observational constraints further measurements are necessary to constrain the cooling process. Implications are discussed for understanding the transport processes in the inner heliosphere and improving this measurement technique.

  17. A novel scheme to handle highly pulsed loads with a standard helium refrigerator

    SciTech Connect (OSTI)

    Slack, D.S.

    1993-06-30

    Helium refrigerator performance degrades rapidly when it has to handle a varying or pulsed heat load. A novel scheme is presented to handle highly pulsed 4.5 K cryogenic loads with a standard helium refrigerator by isolating it from these pulses. The scheme uses a relatively simple arrangement of control valves, heat exchangers, and a storage dewar. Applications include pulsed tokamak machines such as TPX (Tokamak Physics Experiment) and ITER (International Thermonuclear Experimental Reactor). For example, the TPX (currently in the conceptual design phase in a DoE contract) requires an average 4.5 K refrigerator capacity of about 10 kW; however, pulsed loads caused by eddy current and nuclear heating will exceed 100 kW. The scheme presented here provides a method for handling these pulsed loads. Because of the simple and proven nature of the components involved and the thermodynamic properties of the helium, the system could be implemented for projects such as TPX or ITER with little or no development.

  18. Helium in chirped laser fields as a time-asymmetric atomic switch

    SciTech Connect (OSTI)

    Kaprlov-?nsk, Petra Ruth; Moiseyev, Nimrod

    2014-07-07

    Tuning the laser parameters exceptional points in the spectrum of the dressed laser helium atom are obtained. The weak linearly polarized laser couples the ground state and the doubly excited P-states of helium. We show here that for specific chirped laser pulses that encircle an exceptional point one can get the time-asymmetric phenomenon, where for a negative chirped laser pulse the ground state is transformed into the doubly excited auto-ionization state, while for a positive chirped laser pulse the resonance state is not populated and the neutral helium atoms remains in the ground state as the laser pulse is turned off. Moreover, we show that the results are very sensitive to the closed contour we choose. This time-asymmetric state exchange phenomenon can be considered as a time-asymmetric atomic switch. The optimal time-asymmetric switch is obtained when the closed loop that encircles the exceptional point is large, while for the smallest loops, the time-asymmetric phenomenon does not take place. A systematic way for studying the effect of the chosen closed contour that encircles the exceptional point on the time-asymmetric phenomenon is proposed.

  19. Y-12 begins to separate lithium isotopes

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

    begins to separate lithium isotopes During the years from 1946 through the early 1950s, Y-12 continued to expand as needed to meet the demand for a growing primary mission of...

  20. Atomic vapor laser isotope separation process

    DOE Patents [OSTI]

    Wyeth, R.W.; Paisner, J.A.; Story, T.

    1990-08-21

    A laser spectroscopy system is utilized in an atomic vapor laser isotope separation process. The system determines spectral components of an atomic vapor utilizing a laser heterodyne technique. 23 figs.

  1. Environmental assessment: special isotope separation process selection

    SciTech Connect (OSTI)

    Not Available

    1986-04-01

    This Environmental Assessment (EA) evaluates the differences in potential environmental impacts between two plutonium Special Isotope Separation (SIS) technologies: Atomic Vapor Laser Isotope Separation (AVLIS) and Molecular Laser Isotope Separation (MLIS). Both SIS technologies use PuO/sub 2/ as feed; AVLIS converts feed to plutonium metal and MLIS converts feed to PuF/sub 6/. The AVLIS process uses laser energy to selectively photoionize and electrostatically separate plutonium isotopes from an atomic vapor stream. The MLIS process uses laser energy to selectively disassociate specific isotopes of plutonium in the form of PuF/sub 6/ molecules to create PuF/sub 5/ for collection and further processing. Both processes produce plutonium metal as their product. An evaluation of differences in potential environmental impacts attributed to the construction of an SIS facility, based on either technology, included a comparison of construction materials, land areas required, and the size of the design and construction workforce. The differences in potential environmental impacts from operating an SIS facility were also compared. No large differences in potential environmental impacts would be expected from the use of process chemicals. An AVLIS or an MLIS facility would produce operating effluents that would meet all applicable radiation, chemical, and hazardous waste standards and would be constructed to protect workers, the public and the environment. This EA has not revealed any significant differences in the potential environmental impacts that could occur as a result of deploying either the AVLIS or the MLIS Special Isotope Separation technology.

  2. Investigation of Countercurrent Helium-Air Flows in Air-ingress Accidents for VHTRs

    SciTech Connect (OSTI)

    Sun, Xiaodong; Christensen, Richard; Oh, Chang

    2013-10-03

    The primary objective of this research is to develop an extensive experimental database for the air- ingress phenomenon for the validation of computational fluid dynamics (CFD) analyses. This research is intended to be a separate-effects experimental study. However, the project team will perform a careful scaling analysis prior to designing a scaled-down test facility in order to closely tie this research with the real application. As a reference design in this study, the team will use the 600 MWth gas turbine modular helium reactor (GT-MHR) developed by General Atomic. In the test matrix of the experiments, researchers will vary the temperature and pressure of the helium— along with break size, location, shape, and orientation—to simulate deferent scenarios and to identify potential mitigation strategies. Under support of the Department of Energy, a high-temperature helium test facility has been designed and is currently being constructed at Ohio State University, primarily for high- temperature compact heat exchanger testing for the VHTR program. Once the facility is in operation (expected April 2009), this study will utilize high-temperature helium up to 900°C and 3 MPa for loss-of-coolant accident (LOCA) depressurization and air-ingress experiments. The project team will first conduct a scaling study and then design an air-ingress test facility. The major parameter to be measured in the experiments is oxygen (or nitrogen) concentration history at various locations following a LOCA scenario. The team will use two measurement techniques: 1) oxygen (or similar type) sensors employed in the flow field, which will introduce some undesirable intrusiveness, disturbing the flow, and 2) a planar laser-induced fluorescence (PLIF) imaging technique, which has no physical intrusiveness to the flow but requires a transparent window or test section that the laser beam can penetrate. The team will construct two test facilities, one for high-temperature helium tests with

  3. Strategic Perspectives on Biofuels

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

    Perspectives on Biofuels Bioenergy 2015: Opportunities in a Changing Energy Landscape Washington, DC June 24, 2015 Lee Rybeck Lynd Thayer School of Engineering, Dartmouth College Global Sustainable Bioenergy Project Bioenergy Science Center Enchi Corp. Thayer School of Engineering, Dartmouth GSB Global Sustainable Bioenergy The two biggest energy supply challenges to get to a low-carbon world Second half of low-carbon electricity - in light of intermittency of other renewables Second half of

  4. Manufacturing Perspective | Department of Energy

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

    Perspective Manufacturing Perspective Presented at the R&D Strategies for Compressed, Cryo-Compressed and Cryo-Sorbent Hydrogen Storage Technologies Workshops on February 14 and 15, 2011. compressed_hydrogen2011_5_nelson.pdf (1.68 MB) More Documents & Publications BCA Perspective on Fuel Cell APUs Energy Storage Systems 2006 Peer Review - Day 1 morning presentations 2015 SSL R&D WORKSHOP PRESENTATIONS - DAY 3

  5. Renewable Natural Gas- Developer Perspective

    Broader source: Energy.gov [DOE]

    Breakout Session 3-C: Renewable Gaseous FuelsRenewable Natural Gas - Developer PerspectiveDavid Ross, Managing Director, MultiGen International, LLC

  6. TRIFID (TRansuranic Isotopic Fraction Interrogation Device): A second generation plutonium isotopic analysis system

    SciTech Connect (OSTI)

    Fleissner, J G; Coressel, T W; Freier, D A; Macklin, L L

    1989-01-01

    The TRIFID (Transuranic Isotopic Fraction Interrogation Device) system is a second generation plutonium isotopic analysis system which incorporates many new and unique features in the area of isotopic data acquisition and isotopic analysis instrument consisting of a Canberra Series 95-MCA interfaced to a Compaq 386 computer. The entire TRIFID software package, including MCA communications and isotopic analysis routines, was developed using the C programming language. Extensive use has been made of user friendly screens and menus for ease of operation and training and to facilitate use by technical level operators. Automated TRIFID features provide for MCA/ADC setup and acquisition, spectral storage, isotopic analysis, and report generation. One unique feature of the TRIFID system design allows it to be pre-programed for an entire day's counting. The isotopic analysis module (EPICS) contains an expert system formalism which is used to detect and assay for spectral interferences, and to automatically adjust peak fitting constraints based on spectral intensity variations. A TRIFID system has been in operation in a production laboratory at the Rocky Flats Plant since September 1988. Marked decreases in training and hands-on operation time have been achieved in comparison to the older, preceding isotopic systems. 2 refs., 3 figs.

  7. Nucleosynthesis in helium-enriched asymptotic giant branch models: Implications for heavy element enrichment in ω Centauri

    SciTech Connect (OSTI)

    Karakas, Amanda I.; Marino, Anna F.; Nataf, David M.

    2014-03-20

    We investigate the effect of helium enrichment on the evolution and nucleosynthesis of low-mass asymptotic giant branch (AGB) stars of 1.7 M {sub ☉} and 2.36 M {sub ☉} with a metallicity of Z = 0.0006 ([Fe/H] ≈–1.4). We calculate evolutionary sequences with the primordial helium abundance (Y = 0.24) and with helium-enriched compositions (Y = 0.30, 0.35, 0.40). For comparison, we calculate models of the same mass but at a lower metallicity Z = 0.0003 ([Fe/H] ≈–1.8) with Y = 0.24. Post-processing nucleosynthesis calculations are performed on each of the evolutionary sequences to determine the production of elements from hydrogen to bismuth. Elemental surface abundance predictions and stellar yields are presented for each model. The models with enriched helium have shorter main sequence and AGB lifetimes, and they enter the AGB with a more massive hydrogen-exhausted core than the primordial helium model. The main consequences are as follows: (1) low-mass AGB models with enhanced helium will evolve more than twice as fast, giving them the chance to contribute sooner to the chemical evolution of the forming globular clusters, and (2) the stellar yields will be strongly reduced relative to their primordial helium counterparts. An increase of ΔY = 0.10 at a given mass decreases the yields of carbon by up to ≈60% and of fluorine by up to 80%; it also decreases the yields of the s-process elements barium and lanthanum by ≈45%. While the yields of first s-process peak elements strontium, yttrium, and zirconium decrease by up to 50%, the yields of rubidium either do not change or increase.

  8. DNA Origami: A History and Current Perspective

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

    Origami: A History and Current Perspective Authors: Nangreave, J., Han, D., Liu, Y., and Yan, H. Title: DNA Origami: A History and Current Perspective Source: Current Opinion in ...

  9. Perspective & Acquisition Fellows Program - David Klaus, Deputy...

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

    Perspective & Acquisition Fellows Program - David Klaus, Deputy Under Secretary for Management and Performance Perspective & Acquisition Fellows Program - David Klaus, Deputy Under ...

  10. Climate Perspectives: Change in the Terrestrial Arctic

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

    Perspectives: Change in the Terrestrial Arctic Climate Perspectives An interactive exploration of Arctic climate science through prisms of the visual arts, literary arts, info-vis, ...

  11. Fuel Cells at Supermarkets: NYSERDA's Perspective | Department...

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

    at Supermarkets: NYSERDA's Perspective Fuel Cells at Supermarkets: NYSERDA's Perspective Presented at the Clean Energy States Alliance and U.S. Department of Energy Webinar: Fuel ...

  12. Project Management Perspective - Paul Bosco, Director, Office...

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

    Project Management Perspective - Paul Bosco, Director, Office of Acquisition and Project Management Project Management Perspective - Paul Bosco, Director, Office of Acquisition and ...

  13. Laser Isotope Separation Employing Condensation Repression

    SciTech Connect (OSTI)

    Eerkens, Jeff W.; Miller, William H.

    2004-09-15

    Molecular laser isotope separation (MLIS) techniques using condensation repression (CR) harvesting are reviewed and compared with atomic vapor laser isotope separation (AVLIS), gaseous diffusion (DIF), ultracentrifuges (UCF), and electromagnetic separations (EMS). Two different CR-MLIS or CRISLA (Condensation Repression Isotope Separation by Laser Activation) approaches have been under investigation at the University of Missouri (MU), one involving supersonic super-cooled free jets and dimer formation, and the other subsonic cold-wall condensation. Both employ mixtures of an isotopomer (e.g. {sup i}QF{sub 6}) and a carrier gas, operated at low temperatures and pressures. Present theories of VT relaxation, dimerization, and condensation are found to be unsatisfactory to explain/predict experimental CRISLA results. They were replaced by fundamentally new models that allow ab-initio calculation of isotope enrichments and predictions of condensation parameters for laser-excited and non-excited vapors which are in good agreement with experiment. Because of supersonic speeds, throughputs for free-jet CRISLA are a thousand times higher than cold-wall CRISLA schemes, and thus preferred for large-quantity Uranium enrichments. For small-quantity separations of (radioactive) medical isotopes, the simpler coldwall CRISLA method may be adequate.

  14. General Motors Perspective

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

    Motors Perspective Dr.-Ing. Wolfgang Oelerich Adam Opel AG GM Alternative Propulsion Center Europe Compressed & Cryo- Compressed Hydrogen Storage Workshop 14 th / 15 th February 2011 Washington DC Chevrolet Equinox as Part of GM's Global "Project Driveway" Power: 73 kW Acceleration (0-100 km/h): 12 s Top speed: 160 km/h Fuel: 4.2 kg Compressed Hydrogen Gas (70 MPa) in three Type 4 filament wound carbon fiber composite vessels Range: 320 km Over 2.5 million km (1.5 million miles)

  15. Perspectives on reactor safety

    SciTech Connect (OSTI)

    Haskin, F.E.; Camp, A.L.

    1994-03-01

    The US Nuclear Regulatory Commission (NRC) maintains a technical training center at Chattanooga, Tennessee to provide appropriate training to both new and experienced NRC employees. This document describes a one-week course in reactor, safety concepts. The course consists of five modules: (1) historical perspective; (2) accident sequences; (3) accident progression in the reactor vessel; (4) containment characteristics and design bases; and (5) source terms and offsite consequences. The course text is accompanied by slides and videos during the actual presentation of the course.

  16. Dose dependence of helium bubble formation in nano-engineered SiC at 700 °C

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

    Chen, Chien -Hung; Zhang, Yanwen; Wang, Yongqiang; Crespillo, Miguel L.; Fontana, Cristiano L.; Graham, Joseph T.; Duscher, Gerd; Shannon, Steven C.; Weber, William J.

    2016-02-03

    Knowledge of radiation-induced helium bubble nucleation and growth in SiC is essential for applications in fusion and fission environments. Here we report the evolution of microstructure in nano-engineered (NE) 3C SiC, pre-implanted with helium, under heavy ion irradiation at 700 °C up to doses of 30 displacements per atom (dpa). Elastic recoil detection analysis confirms that the as-implanted helium depth profile does not change under irradiation to 30 dpa at 700 °C. While the helium bubble size distribution becomes narrower with increasing dose, the average size of bubbles remains unchanged and the density of bubbles increases somewhat with dose. Thesemore » results are consistent with a long helium bubble incubation process under continued irradiation at 700 °C up to 30 dpa, similar to that reported under dual and triple beam irradiation at much higher temperatures. The formation of bubbles at this low temperature is enhanced by the nano-layered stacking fault structure in the NE SiC, which enhances point defect mobility parallel to the stacking faults. Here, this stacking fault structure is stable at 700 °C up to 30 dpa and suppresses the formation of dislocation loops normally observed under these irradiation conditions.« less

  17. Use of Multiple Reheat Helium Brayton Cycles to Eliminate the Intermediate Heat Transfer Loop for Advanced Loop Type SFRs

    SciTech Connect (OSTI)

    Haihua Zhao; Hongbin Zhang; Samuel E. Bays

    2009-05-01

    The sodium intermediate heat transfer loop is used in existing sodium cooled fast reactor (SFR) plant design as a necessary safety measure to separate the radioactive primary loop sodium from the water of the steam Rankine power cycle. However, the intermediate heat transfer loop significantly increases the SFR plant cost and decreases the plant reliability due to the relatively high possibility of sodium leakage. A previous study shows that helium Brayton cycles with multiple reheat and intercooling for SFRs with reactor outlet temperature in the range of 510°C to 650°C can achieve thermal efficiencies comparable to or higher than steam cycles or recently proposed supercritical CO2 cycles. Use of inert helium as the power conversion working fluid provides major advantages over steam or CO2 by removing the requirement for safety systems to prevent and mitigate the sodium-water or sodium-CO2 reactions. A helium Brayton cycle power conversion system therefore makes the elimination of the intermediate heat transfer loop possible. This paper presents a pre-conceptual design of multiple reheat helium Brayton cycle for an advanced loop type SFR. This design widely refers the new horizontal shaft distributed PBMR helium power conversion design features. For a loop type SFR with reactor outlet temperature 550°C, the design achieves 42.4% thermal efficiency with favorable power density comparing with high temperature gas cooled reactors.

  18. Diffusion in silicon isotope heterostructures

    SciTech Connect (OSTI)

    Silvestri, Hughes Howland

    2004-05-14

    The simultaneous diffusion of Si and the dopants B, P, and As has been studied by the use of a multilayer structure of isotopically enriched Si. This structure, consisting of 5 pairs of 120 nm thick natural Si and {sup 28}Si enriched layers, enables the observation of {sup 30}Si self-diffusion from the natural layers into the {sup 28}Si enriched layers, as well as dopant diffusion from an implanted source in an amorphous Si cap layer, via Secondary Ion Mass Spectrometry (SIMS). The dopant diffusion created regions of the multilayer structure that were extrinsic at the diffusion temperatures. In these regions, the Fermi level shift due to the extrinsic condition altered the concentration and charge state of the native defects involved in the diffusion process, which affected the dopant and self-diffusion. The simultaneously recorded diffusion profiles enabled the modeling of the coupled dopant and self-diffusion. From the modeling of the simultaneous diffusion, the dopant diffusion mechanisms, the native defect charge states, and the self- and dopant diffusion coefficients can be determined. This information is necessary to enhance the physical modeling of dopant diffusion in Si. It is of particular interest to the modeling of future electronic Si devices, where the nanometer-scale features have created the need for precise physical models of atomic diffusion in Si. The modeling of the experimental profiles of simultaneous diffusion of B and Si under p-type extrinsic conditions revealed that both species are mediated by neutral and singly, positively charged Si self-interstitials. The diffusion of As and Si under extrinsic n-type conditions yielded a model consisting of the interstitialcy and vacancy mechanisms of diffusion via singly negatively charged self-interstitials and neutral vacancies. The simultaneous diffusion of P and Si has been modeled on the basis of neutral and singly negatively charged self-interstitials and neutral and singly positively charged P

  19. A passively-safe fusion reactor blanket with helium coolant and steel structure

    SciTech Connect (OSTI)

    Crosswait, K.M.

    1994-04-01

    Helium is attractive for use as a fusion blanket coolant for a number of reasons. It is neutronically and chemically inert, nonmagnetic, and will not change phase during any off-normal or accident condition. A significant disadvantage of helium, however, is its low density and volumetric heat capacity. This disadvantage manifests itself most clearly during undercooling accident conditions such as a loss of coolant accident (LOCA) or a loss of flow accident (LOFA). This thesis describes a new helium-cooled tritium breeding blanket concept which performs significantly better during such accidents than current designs. The proposed blanket uses reduced-activation ferritic steel as a structural material and is designed for neutron wall loads exceeding 4 MW/m{sup 2}. The proposed geometry is based on the nested-shell concept developed by Wong, but some novel features are used to reduce the severity of the first wall temperature excursion. These features include the following: (1) A ``beryllium-joint`` concept is introduced, which allows solid beryllium slabs to be used as a thermal conduction path from the first wall to the cooler portions of the blanket. The joint concept allows for significant swelling of the beryllium (10 percent or more) without developing large stresses in the blanket structure. (2) Natural circulation of the coolant in the water-cooled shield is used to maintain shield temperatures below 100 degrees C, thus maintaining a heat sink close to the blanket during the accident. This ensures the long-term passive safety of the blanket.

  20. Helium transport and ash control studies. Annual progress report, 1 June 1991--31 March 1992

    SciTech Connect (OSTI)

    Miley, G.H.

    1992-06-01

    The Primary goal of this research is to develop a helium (ash) transport scaling law based on experimental data from devices such as TFTR and JET. To illustrate the importance of this, we have studied ash accumulation effects on ignition requirements using a O-D transport model. Ash accumulation is characterized in the model by the ratio of the helium particle confinement time to the energy confinement time t{sub {alpha}}/t{sub E}. Results show that the ignition ``window`` shrinks rapidly as t{sub {alpha}}/t{sub E} increases, closing for high t{sub {alpha}}/t{sub E} increases, closing for high t{sub {alpha}}/t{sub E}. A ``best`` value for t{sub {alpha}}/t{sub E} will ultimately be determined from our scaling law studies. A helium transport scaling law is being sought that expresses the transport coefficients (D{sub {alpha}}, V{sub {alpha}}) as a function of the local plasma parameters. This is necessary for use in transport code calculations, e.g. for BALDUR. Based on experimental data from L-mode plasma operation in TFTR, a scaling law to a power law expression has been obtained using a least-square fit method. It is found that the transport coefficients are strongly affected by the local magnetic field and safety factor q. A preliminary conclusion from this work is that active control of ash buildup must be developed. To study control, we have developed a O-D plasma model which employs a simple pole-placement control model. Some preliminary calculations with this model are presented.

  1. Probing Electron Correlation via Attosecond xuv Pulses in the Two-Photon Double Ionization of Helium

    SciTech Connect (OSTI)

    Feist, J.; Nagele, S.; Pazourek, R.; Persson, E.; Burgdoerfer, J.; Schneider, B. I.; Collins, L. A.

    2009-08-07

    Recent experimental developments of high-intensity, short-pulse extreme ultraviolet light sources are enhancing our ability to study electron-electron correlations. We perform time-dependent calculations to investigate the so-called 'sequential' regime ((Planck constant/2pi)omega>54.4 eV) in the two-photon double ionization of helium. We show that attosecond pulses allow us not only to probe but also to induce angular and energy correlations of the emitted electrons. The final momentum distribution reveals regions dominated by the Wannier ridge breakup scenario and by postcollision interaction.

  2. Deep Burn Develpment of Transuranic Fuel for High-Temperature Helium-Cooled Reactors - July 2010

    SciTech Connect (OSTI)

    Snead, Lance Lewis; Besmann, Theodore M; Collins, Emory D; Bell, Gary L

    2010-08-01

    The DB Program Quarterly Progress Report for April - June 2010, ORNL/TM/2010/140, was distributed to program participants on August 4. This report discusses the following: (1) TRU (transuranic elements) HTR (high temperature helium-cooled reactor) Fuel Modeling - (a) Thermochemical Modeling, (b) 5.3 Radiation Damage and Properties; (2) TRU HTR Fuel Qualification - (a) TRU Kernel Development, (b) Coating Development, (c) ZrC Properties and Handbook; and (3) HTR Fuel Recycle - (a) Recycle Processes, (b) Graphite Recycle, (c) Pyrochemical Reprocessing - METROX (metal recovery from oxide fuel) Process Development.

  3. Fabrication of carbon nanotube nanogap electrodes by helium ion sputtering for molecular contacts

    SciTech Connect (OSTI)

    Thiele, Cornelius; Vieker, Henning; Beyer, André; Gölzhäuser, Armin; Flavel, Benjamin S.; Hennrich, Frank; Muñoz Torres, David; Eaton, Thomas R.; Mayor, Marcel; Kappes, Manfred M.; Löhneysen, Hilbert v.; and others

    2014-03-10

    Carbon nanotube nanogaps have been used to contact individual organic molecules. However, the reliable fabrication of a truly nanometer-sized gap remains a challenge. We use helium ion beam lithography to sputter nanogaps of only (2.8 ± 0.6) nm size into single metallic carbon nanotubes embedded in a device geometry. The high reproducibility of the gap size formation provides a reliable nanogap electrode testbed for contacting small organic molecules. To demonstrate the functionality of these nanogap electrodes, we integrate oligo(phenylene ethynylene) molecular rods, and measure resistance before and after gap formation and with and without contacted molecules.

  4. Numerical simulation of alumina spraying in argon-helium plasma jet

    SciTech Connect (OSTI)

    Chang, C.H.

    1992-01-01

    A new numerical model is described for simulating thermal plasmas containing entrained particles, with emphasis on plasma spraying applications. The plasma is represented as a continuum multicomponent chemically reacting ideal gas, while the particles are tracked as discrete Lagrangian entities coupled to the plasma. Computational results are presented from a transient simulation of alumina spraying in a turbulent argon-helium plasma jet in air environment, including torch geometry, substrate, and multiple species with chemical reactions. Particle-plasma interactions including turbulent dispersion have been modeled in a fully self-consistent manner. Interactions between the plasma and the torch and substrate walls are modeled using wall functions. (15 refs.)

  5. Numerical simulation of alumina spraying in argon-helium plasma jet

    SciTech Connect (OSTI)

    Chang, C.H.

    1992-08-01

    A new numerical model is described for simulating thermal plasmas containing entrained particles, with emphasis on plasma spraying applications. The plasma is represented as a continuum multicomponent chemically reacting ideal gas, while the particles are tracked as discrete Lagrangian entities coupled to the plasma. Computational results are presented from a transient simulation of alumina spraying in a turbulent argon-helium plasma jet in air environment, including torch geometry, substrate, and multiple species with chemical reactions. Particle-plasma interactions including turbulent dispersion have been modeled in a fully self-consistent manner. Interactions between the plasma and the torch and substrate walls are modeled using wall functions. (15 refs.)

  6. Atomic line emission analyzer for hydrogen isotopes

    DOE Patents [OSTI]

    Kronberg, J.W.

    1993-03-30

    Apparatus for isotopic analysis of hydrogen comprises a low pressure chamber into which a sample of hydrogen is introduced and then exposed to an electrical discharge to excite the electrons of the hydrogen atoms to higher energy states and thereby cause the emission of light on the return to lower energy states, a Fresnel prism made at least in part of a material anomalously dispersive to the wavelengths of interest for dispersing the emitted light, and a photodiode array for receiving the dispersed light. The light emitted by the sample is filtered to pass only the desired wavelengths, such as one of the lines of the Balmer series for hydrogen, the wavelengths of which differ slightly from one isotope to another. The output of the photodiode array is processed to determine the relative amounts of each isotope present in the sample. Additionally, the sample itself may be recovered using a metal hydride.

  7. Atomic line emission analyzer for hydrogen isotopes

    DOE Patents [OSTI]

    Kronberg, James W.

    1993-01-01

    Apparatus for isotopic analysis of hydrogen comprises a low pressure chamber into which a sample of hydrogen is introduced and then exposed to an electrical discharge to excite the electrons of the hydrogen atoms to higher energy states and thereby cause the emission of light on the return to lower energy states, a Fresnel prism made at least in part of a material anomalously dispersive to the wavelengths of interest for dispersing the emitted light, and a photodiode array for receiving the dispersed light. The light emitted by the sample is filtered to pass only the desired wavelengths, such as one of the lines of the Balmer series for hydrogen, the wavelengths of which differ slightly from one isotope to another. The output of the photodiode array is processed to determine the relative amounts of each isotope present in the sample. Additionally, the sample itself may be recovered using a metal hydride.

  8. Atomic line emission analyzer for hydrogen isotopes

    DOE Patents [OSTI]

    Kronberg, J.W.

    1991-05-08

    Apparatus for isotopic analysis of hydrogen comprises a low pressure chamber into which a sample of hydrogen is introduced and then exposed to an electrical discharge to excite the electrons of the hydrogen atoms to higher energy states and thereby cause the emission of light on the return to lower energy states, a Fresnel prism made at least in part of a material anomalously dispersive to the wavelengths of interest for dispersing the emitted light, and a photodiode array for receiving the dispersed light. The light emitted by the sample is filtered to pass only the desired wavelengths, such as one of the lines of the Balmer series for hydrogen, the wavelengths of which differ slightly from one isotope to another. The output of the photodiode array is processed to determine the relative amounts of each isotope present in the sample. Additionally, the sample itself may be recovered using, a metal hydride.

  9. Apparatus for separating and recovering hydrogen isotopes

    DOE Patents [OSTI]

    Heung, Leung K.

    1994-01-01

    An apparatus for recovering hydrogen and separating its isotopes. The apparatus includes a housing bearing at least a fluid inlet and a fluid outlet. A baffle is disposed within the housing, attached thereto by a bracket. A hollow conduit is coiled about the baffle, in spaced relation to the baffle and the housing. The coiled conduit is at least partially filled with a hydride. The hydride can be heated to a high temperature and cooled to a low temperature quickly by circulating a heat transfer fluid in the housing. The spacing between the baffle and the housing maximizes the heat exchange rate between the fluid in the housing and the hydride in the conduit. The apparatus can be used to recover hydrogen isotopes (protium, deuterium and tritium) from gaseous mixtures, or to separate hydrogen isotopes from each other.

  10. Isotopic abundance in atom trap trace analysis

    DOE Patents [OSTI]

    Lu, Zheng-Tian; Hu, Shiu-Ming; Jiang, Wei; Mueller, Peter

    2014-03-18

    A method and system for detecting ratios and amounts of isotopes of noble gases. The method and system is constructed to be able to measure noble gas isotopes in water and ice, which helps reveal the geological age of the samples and understand their movements. The method and system uses a combination of a cooled discharge source, a beam collimator, a beam slower and magneto-optic trap with a laser to apply resonance frequency energy to the noble gas to be quenched and detected.

  11. Laser isotope separation by multiple photon absorption

    DOE Patents [OSTI]

    Robinson, C. Paul; Rockwood, Stephen D.; Jensen, Reed J.; Lyman, John L.; Aldridge, III, Jack P.

    1987-01-01

    Multiple photon absorption from an intense beam of infrared laser light may be used to induce selective chemical reactions in molecular species which result in isotope separation or enrichment. The molecular species must have a sufficient density of vibrational states in its vibrational manifold that, is the presence of sufficiently intense infrared laser light tuned to selectively excite only those molecules containing a particular isotope, multiple photon absorption can occur. By this technique, for example, intense CO.sub.2 laser light may be used to highly enrich .sup.34 S in natural SF.sub.6 and .sup.11 B in natural BCl.sub.3.

  12. Laser isotope separation by multiple photon absorption

    DOE Patents [OSTI]

    Robinson, C. Paul; Rockwood, Stephen D.; Jensen, Reed J.; Lyman, John L.; Aldridge, III, Jack P.

    1977-01-01

    Multiple photon absorption from an intense beam of infrared laser light may be used to induce selective chemical reactions in molecular species which result in isotope separation or enrichment. The molecular species must have a sufficient density of vibrational states in its vibrational manifold that, in the presence of sufficiently intense infrared laser light tuned to selectively excite only those molecules containing a particular isotope, multiple photon absorption can occur. By this technique, for example, intense CO.sub.2 laser light may be used to highly enrich .sup.34 S in natural SF.sub.6 and .sup.11 B in natural BCl.sub.3.

  13. Laser isotope separation by multiple photon absorption

    DOE Patents [OSTI]

    Robinson, C.P.; Rockwood, S.D.; Jensen, R.J.; Lyman, J.L.; Aldridge, J.P. III.

    1987-04-07

    Multiple photon absorption from an intense beam of infrared laser light may be used to induce selective chemical reactions in molecular species which result in isotope separation or enrichment. The molecular species must have a sufficient density of vibrational states in its vibrational manifold that, is the presence of sufficiently intense infrared laser light tuned to selectively excite only those molecules containing a particular isotope, multiple photon absorption can occur. By this technique, for example, intense CO[sub 2] laser light may be used to highly enrich [sup 34]S in natural SF[sub 6] and [sup 11]B in natural BCl[sub 3]. 8 figs.

  14. Principles of isotope geology. Second edition

    SciTech Connect (OSTI)

    Faure, G.

    1986-01-01

    This is a text in isotope geology/geoscience that integrates material taught in various courses into a unified picture of the earth sciences. It presents an exposition of the principles used in the interpretation of isotopic data and shows how such interpretations apply to the solution of geological problems. References up to 1985 are included with chapters in this edition. New chapters on Sm-Nd, Lu-Hf Re-Os, and K-Ca decay schemes and cosmogenic radionuclides have been added. Data summaries and references have been expanded.

  15. Overview of the U.S. Department of Energy's Isotope Programs

    SciTech Connect (OSTI)

    Carty, J.

    2004-10-05

    This presentation provides an overview of the U.S. Department of Energy's Isotopes Program. The charter of the Isotope Programs covers the production and sale of radioactive and stable isotopes, associated byproducts, surplus materials, and related isotope services.

  16. Method for production of an isotopically enriched compound

    DOE Patents [OSTI]

    Watrous, Matthew G.

    2012-12-11

    A method is presented for producing and isolating an isotopically enriched compound of a desired isotope from a parent radionuclide. The method includes forming, or placing, a precipitate containing a parent radionuclide of the desired daughter isotope in a first reaction zone and allowing sufficient time for the parent to decay into the desired gaseous daughter radioisotope. The method further contemplates collecting the desired daughter isotope as a solid in a second reaction zone through the application of temperatures below the freezing point of the desired isotope to a second reaction zone that is connected to the first reaction zone. Specifically, a method is presented for producing isotopically enriched compounds of xenon, including the radioactive isotope Xe-131m and the stable isotope Xe-131.

  17. Motivation for New Measurements on 241, 242, 243Am Isotopes ...

    Office of Scientific and Technical Information (OSTI)

    Motivation for New Measurements on 241, 242, 243Am Isotopes Citation Details In-Document Search Title: Motivation for New Measurements on 241, 242, 243Am Isotopes The initial ...

  18. Ion laser isotope enrichment by photo-predissociation of formaldehyde

    DOE Patents [OSTI]

    Marling, John B.

    1977-06-17

    Enrichment of carbon, hydrogen and/or oxygen isotopes by means of isotopically selective photo-predissociation of formaldehyde is achieved by irradiation with a fixed frequency ion laser, specifically, a neon, cadmium, or xenon ion laser.

  19. Report of Survey of Oak Ridge Isotope Enrichment (Calutron) Facility...

    Office of Environmental Management (EM)

    Report of Survey of Oak Ridge Isotope Enrichment (Calutron) Facility Building 9204-3 Report of Survey of Oak Ridge Isotope Enrichment (Calutron) Facility Building 9204-3 The ...

  20. OSTIblog Articles in the High Flux Isotope Reactor Topic | OSTI...

    Office of Scientific and Technical Information (OSTI)

    High Flux Isotope Reactor Topic The NXS Class of 2014 by Kathy Chambers 19 Nov, 2014 in ... National Laboratory, High Flux Isotope Reactor, National School on Neutron and X-ray ...

  1. Physicist wins early-career award for isotope work

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

    Physicist wins early-career award for isotope work Physicist wins early-career award for ... of Los Alamos research in isotopes with important new medical advances," said Alan Bishop. ...

  2. Cavity morphology in a Ni based superalloy under heavy ion irradiation with cold pre-injected helium. I

    SciTech Connect (OSTI)

    Zhang, He; Yao, Zhongwen Daymond, Mark R.; Kirk, Marquis A.

    2014-03-14

    In order to understand radiation damage in the nickel based superalloy Inconel X-750 in thermal reactors, where (n, ?) transmutation reaction also occurred in addition to fast neutron induced atomic displacement, heavy ion (1?MeV Kr{sup 2+}) irradiation with pre-injected helium was performed under in-situ observations of an intermediate voltage electron microscope at Argonne National Laboratory. By comparing to our previous studies using 1?MeV Kr{sup 2+} irradiation solely, the pre-injected helium was found to be essential in cavity nucleation. Cavities started to be visible after Kr{sup 2+} irradiation to 2.7 dpa at ?200?C in samples containing 200 appm, 1000 appm, and 5000 appm helium, respectively, but not at lower temperatures. The cavity growth was observed during the continuous irradiation. Cavity formation appeared along with a reduced number density of stacking fault tetrahedra, vacancy type defects. With higher pre-injected helium amount, a higher density of smaller cavities was observed. This is considered to be the result of local trapping effect of helium which disperses vacancies. The average cavity size increases with increasing irradiation temperatures; the density reduced; and the distribution of cavities became heterogeneous at elevated temperatures. In contrast to previous characterization of in-reactor neutron irradiated Inconel X-750, no obvious cavity sink to grain boundaries and phase boundaries was found even at high doses and elevated temperatures. MC-type carbides were observed as strong sources for agglomeration of cavities due to their enhanced trapping strength of helium and vacancies.

  3. Isotopic Analysis- Rock At Coso Geothermal Area (1984) | Open...

    Open Energy Info (EERE)

    Home Exploration Activity: Isotopic Analysis- Rock At Coso Geothermal Area (1984) Exploration Activity Details Location Coso Geothermal Area Exploration Technique...

  4. Cancer-fighting treatment gets boost from Isotope Production Facility

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

    Cancer-fighting treatment gets boost from Isotope Production Facility Cancer-fighting treatment gets boost from Isotope Production Facility New capability expands existing program, creates treatment product in quantity. April 13, 2012 Medical Isotope Work Moves Cancer Treatment Agent Forward Medical Isotope Work Moves Cancer Treatment Agent Forward - Los Alamos scientist Meiring Nortier holds a thorium foil test target for the proof-of-concept production experiments. Research indicates that it

  5. Influence of helium puff on divertor asymmetry in Experimental Advanced Superconducting Tokamak

    SciTech Connect (OSTI)

    Liu, S. C., E-mail: lshch@ipp.ac.cn; Xu, G. S.; Wang, H. Q.; Ding, R.; Duan, Y. M.; Gan, K. F.; Shao, L. M.; Chen, L.; Zhang, W.; Chen, R.; Xiong, H.; Ding, S.; Hu, G. H.; Liu, Y. L.; Zhao, N.; Li, Y. L.; Gao, X. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)] [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Guo, H. Y. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China) [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Tri Alpha Energy, Inc., Post Office Box 7010, Rancho Santa Margarita, California 92688 (United States); Wang, L. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China) [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); School of Physics and Optoelectronic Technology, Dalian university of Technology, Dalian 116024 (China); Yan, N. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China) [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Association Euratom-Ris DTU, DK-4000 Roskilde (Denmark)

    2014-02-15

    Divertor asymmetries with helium puffing are investigated in various divertor configurations on Experimental Advanced Superconducting Tokamak (EAST). The outer divertor electron temperature decreases significantly during the gas injection at the outer midplane. As soon as the gas is injected into the edge plasma, the power deposition drops sharply at the lower outer target while increases gradually at the lower inner target in LSN configuration; the power deposition increases quickly at the upper outer target while remains unchanged at the upper inner target in upper single null configuration; the power deposition increases slightly at the outer targets while shows no obvious variation at the inner targets in double null configuration. The radiated power measured by the extreme ultraviolet arrays increases significantly due to helium gas injection, especially in the outer divertor. The edge parameters are measured by reciprocating probes at the outer midplane, showing that the electron temperature and density increase but the parallel Mach number decreases significantly due to the gas injection. Effects of poloidal E??B drifts and parallel SOL flows on the divertor asymmetry observed in EAST are also discussed.

  6. Constraints on helium enhancement in the globular cluster M4 (NGC 6121): The horizontal branch test

    SciTech Connect (OSTI)

    Valcarce, A. A. R.; De Medeiros, J. R.; Catelan, M.; Alonso-Garca, J.; Corts, C.

    2014-02-20

    Recent pieces of evidence have revealed that most, and possibly all, globular star clusters are composed of groups of stars that formed in multiple episodes with different chemical compositions. In this sense, it has also been argued that variations in the initial helium abundance (Y) from one population to the next are also the rule, rather than the exception. In the case of the metal-intermediate globular cluster M4 (NGC 6121), recent high-resolution spectroscopic observations of blue horizontal branch (HB) stars (i.e., HB stars hotter than the RR Lyrae instability strip) suggest that a large fraction of blue HB stars are second-generation stars formed with high helium abundances. In this paper, we test this scenario by using recent photometric and spectroscopic data together with theoretical evolutionary computations for different Y values. Comparing the photometric data with the theoretically derived color-magnitude diagrams, we find that the bulk of the blue HB stars in M4 have ?Y ? 0.01 with respect to the cluster's red HB stars (i.e., HB stars cooler than the RR Lyrae strip)a result which is corroborated by comparison with spectroscopically derived gravities and temperatures, which also favor little He enhancement. However, the possible existence of a minority population on the blue HB of the cluster with a significant He enhancement level is also discussed.

  7. Unusual behavior in magnesium-copper cluster matter produced by helium droplet mediated deposition

    SciTech Connect (OSTI)

    Emery, S. B. Little, B. K.; Xin, Y.; Ridge, C. J.; Lindsay, C. M.; Buszek, R. J.; Boatz, J. A.; Boyle, J. M.

    2015-02-28

    We demonstrate the ability to produce core-shell nanoclusters of materials that typically undergo intermetallic reactions using helium droplet mediated deposition. Composite structures of magnesium and copper were produced by sequential condensation of metal vapors inside the 0.4 K helium droplet baths and then gently deposited onto a substrate for analysis. Upon deposition, the individual clusters, with diameters ∼5 nm, form a cluster material which was subsequently characterized using scanning and transmission electron microscopies. Results of this analysis reveal the following about the deposited cluster material: it is in the un-alloyed chemical state, it maintains a stable core-shell 5 nm structure at sub-monolayer quantities, and it aggregates into unreacted structures of ∼75 nm during further deposition. Surprisingly, high angle annular dark field scanning transmission electron microscopy images revealed that the copper appears to displace the magnesium at the core of the composite cluster despite magnesium being the initially condensed species within the droplet. This phenomenon was studied further using preliminary density functional theory which revealed that copper atoms, when added sequentially to magnesium clusters, penetrate into the magnesium cores.

  8. THE VALUE OF HELIUM-COOLED REACTOR TECHNOLOGIES OF NUCLEAR WASTE

    SciTech Connect (OSTI)

    C. RODRIGUEZ; A. BAXTER

    2001-03-01

    Helium-cooled reactor technologies offer significant advantages in accomplishing the waste transmutation process. They are ideally suited for use with thermal, epithermal, or fast neutron energy spectra. They can provide a relatively hard thermal neutron spectrum for transmutation of fissionable materials such as Pu-239 using ceramic-coated transmutation fuel particles, a graphite moderator, and a non-fertile burnable poison. These features (1) allow deep levels of transmutation with minimal or no intermediate reprocessing, (2) enhance passive decay heat removal via heat conduction and radiation, (3) allow operation at relatively high temperatures for a highly efficient generation of electricity, and (4) discharge the transmuted waste in a form that is highly resistant to corrosion for long times. They also offer the possibility for the use of epithermal neutrons that can interact with transmutable materials more effectively because of the large atomic cross sections in this energy domain. A fast spectrum may be useful for deep burnup of certain minor actinides. For this application, helium is essentially transparent to neutrons, does not degrade neutron energies, and offers the hardest possible neutron energy environment. In this paper, we report results from recent work on materials transmutation balances, safety, value to a geological repository, and economic considerations.

  9. Helium bubble linkage and the transition to rapid He release in aging Pd tritide.

    SciTech Connect (OSTI)

    Cowgill, Donald F.

    2006-02-01

    A model is presented for the linking of helium bubbles growing in aging metal tritides. Stresses created by neighboring bubbles are found to produce bubble growth toward coalescence. This process is interrupted by the fracture of ligaments between bubble arrays. The condition for ligament fracture percolates through the material to reach external surfaces, leading to material micro-cracking and the release of helium within the linked-bubble cluster. A comparison of pure coalescence and pure fracture mechanisms shows the critical HeM concentration for bubble linkage is not strongly dependent on details of the linkage process. The combined stress-directed growth and fracture process produces predictions for the onset of rapid He release and the He emission rate. Transition to this rapid release state is determined from the physical size of the linked-bubble clusters, which is calculated from dimensional invariants in classical percolation theory. The result is a transition that depends on material dimensions. The onset of bubble linkage and rapid He release are found to be quite sensitive to the bubble spacing distribution, which is log-normal for bubbles nucleated by self-trapping.

  10. Flow instabilities in non-uniformly heated helium jet arrays used for divertor PFCs

    SciTech Connect (OSTI)

    Youchison, Dennis L.

    2015-07-30

    In this study, due to a lack of prototypical experimental data, little is known about the off-normal behavior of recently proposed divertor jet cooling concepts. This article describes a computational fluid dynamics (CFD) study on two jet array designs to investigate their susceptibility to parallel flow instabilities induced by non-uniform heating and large increases in the helium outlet temperature. The study compared a single 25-jet helium-cooled modular divertor (HEMJ) thimble and a micro-jet array with 116 jets. Both have pure tungsten armor and a total mass flow rate of 10 g/s at a 600 C inlet temperature. We investigated flow perturbations caused by a 30 MW/m2 off-normal heat flux applied over a 25 mm2 area in addition to the nominal 5 MW/m2 applied over a 75 mm2 portion of the face. The micro-jet array exhibited lower temperatures and a more uniform surface temperature distribution than the HEMJ thimble. We also investigated the response of a manifolded nine-finger HEMJ assembly using the nominal heat flux and a 274 mm2 heated area.

  11. Determination of effective axion masses in the helium-3 buffer of CAST

    SciTech Connect (OSTI)

    Ruz, J

    2011-11-18

    The CERN Axion Solar Telescope (CAST) is a ground based experiment located in Geneva (Switzerland) searching for axions coming from the Sun. Axions, hypothetical particles that not only could solve the strong CP problem but also be one of the favored candidates for dark matter, can be produced in the core of the Sun via the Primakoff effect. They can be reconverted into X-ray photons on Earth in the presence of strong electromagnetic fields. In order to look for axions, CAST points a decommissioned LHC prototype dipole magnet with different X-ray detectors installed in both ends of the magnet towards the Sun. The analysis of the data acquired during the first phase of the experiment yielded the most restrictive experimental upper limit on the axion-to-photon coupling constant for axion masses up to about 0.02 eV/c{sup 2}. During the second phase, CAST extends its mass sensitivity by tuning the electron density present in the magnetic field region. Injecting precise amounts of helium gas has enabled CAST to look for axion masses up to 1.2 eV/c{sup 2}. This paper studies the determination of the effective axion masses scanned at CAST during its second phase. The use of a helium gas buffer at temperatures of 1.8 K has required a detailed knowledge of the gas density distribution. Complete sets of computational fluid dynamic simulations validated with experimental data have been crucial to obtain accurate results.

  12. Commissioning of helium refrigeration system at JLab for 12 GeV upgrade

    SciTech Connect (OSTI)

    Ganni, Venkatarao; Dixon, Kelly D.; Knudsen, Peter N.; Norton, Robert O.; Creel, Jonathan D.

    2014-01-01

    The new 4.5 K refrigerator system added to the Jefferson Lab (JLab) Central Helium Liquefier (CHL) for the 12 GeV upgrade will double its previous capacity. It includes a 4.5 K cold box system and compressor system with associated oil removal and gas management systems. At its maximum capacity condition, this new system supports an additional 238 g/s 30 K 1.16 bar cold compressor return flow, a 15 g/s 4.5 K liquefaction load and a 12.6 kW 35–55 K shield load. Five more design conditions, ranging from liquefaction to refrigeration and a stand-by/reduced load state, were specified for the sizing and selection of its components. The cold box system is comprised of a 300–60 K vertical cold box that incorporates a liquid nitrogen pre-cooler and a 60–4.5 K horizontal cold box housing seven turbines that are configured in four expansion stages including one Joule-Thompson expander. The helium compression system has five compressors to support three pressure levels in the cold box. This paper will briefly review the salient 4.5 K system design features and discuss the recent commissioning results.

  13. OPTIMAL DESIGN AND OPERATION OF HELIUM REFRIGERATION SYSTEMS USING THE GANNI CYCLE

    SciTech Connect (OSTI)

    Venkatarao Ganni, Peter Knudsen

    2010-04-01

    The constant pressure ratio process, as implemented in the floating pressure - Ganni cycle, is a new variation to prior cryogenic refrigeration and liquefaction cycle designs that allows for optimal operation and design of helium refrigeration systems. This cycle is based upon the traditional equipment used for helium refrigeration system designs, i.e., constant volume displacement compression and critical flow expansion devices. It takes advantage of the fact that for a given load, the expander sets the compressor discharge pressure and the compressor sets its own suction pressure. This cycle not only provides an essentially constant system Carnot efficiency over a wide load range, but invalidates the traditional philosophy that the (‘TS’) design condition is the optimal operating condition for a given load using the as-built hardware. As such, the Floating Pressure- Ganni Cycle is a solution to reduce the energy consumption while increasing the reliability, flexibility and stability of these systems over a wide operating range and different operating modes and is applicable to most of the existing plants. This paper explains the basic theory behind this cycle operation and contrasts it to the traditional operational philosophies presently used.

  14. Production of stable, non-thermal atmospheric pressure rf capacitive plasmas using gases other than helium or neon

    DOE Patents [OSTI]

    Park, Jaeyoung; Henins, Ivars

    2005-06-21

    The present invention enables the production of stable, steady state, non-thermal atmospheric pressure rf capacitive .alpha.-mode plasmas using gases other than helium and neon. In particular, the current invention generates and maintains stable, steady-state, non-thermal atmospheric pressure rf .alpha.-mode plasmas using pure argon or argon with reactive gas mixtures, pure oxygen or air. By replacing rare and expensive helium with more readily available gases, this invention makes it more economical to use atmospheric pressure rf .alpha.-mode plasmas for various materials processing applications.

  15. Discovery of palladium, antimony, tellurium, iodine, and xenon isotopes

    SciTech Connect (OSTI)

    Kathawa, J.; Fry, C.; Thoennessen, M., E-mail: thoennessen@nscl.msu.edu

    2013-01-15

    Currently, thirty-eight palladium, thirty-eight antimony, thirty-nine tellurium, thirty-eight iodine, and forty xenon isotopes have been observed and the discovery of these isotopes is described here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.

  16. Spent Nuclear Fuel (SNF) Project Cask and MCO Helium Purge System Design Review Completion Report Project A.5 and A.6

    SciTech Connect (OSTI)

    ARD, K.E.

    2000-04-19

    This report documents the results of the design verification performed on the Cask and Multiple Canister Over-pack (MCO) Helium Purge System. The helium purge system is part of the Spent Nuclear Fuel (SNF) Project Cask Loadout System (CLS) at 100K area. The design verification employed the ''Independent Review Method'' in accordance with Administrative Procedure (AP) EN-6-027-01.

  17. Isotope shifts and nuclear charge radii of krypton isotopes across the N =50 shell closure

    SciTech Connect (OSTI)

    Schuessler, H.A.; Alousi, A.; Evans, R.M.; Brieger, M.; Buchinger, F.; Li, Y.F. Foster Radiation Laboratory, McGill University, Montreal, Quebec )

    1990-09-10

    Optical isotope shifts have been measured in the 5{ital s}(3/2){sub 2}{sup 0}--5{ital p}(3/2){sub 2} transition in atomic krypton ({lambda}=760 nm) using collinear-fast-beam laser spectroscopy. Isotope shifts were determined for the short-lived neutron-rich isotopes {sup 88}Kr and {sup 90}Kr, as well as for all the stable isotopes between {ital A}=78 and 86, thus extending the data in this element, for the first time, beyond the {ital N}=50 shell closure. The deduced changes in the nuclear charge radii show a decrease of the charge radius with increasing neutron number below {ital N}=50, and a much more rapid increase above it. A preliminary interpretation of the results is given in terms of the droplet model.

  18. Laser Isotope Enrichment for Medical and Industrial Applications

    SciTech Connect (OSTI)

    Leonard Bond

    2006-07-01

    Laser Isotope Enrichment for Medical and Industrial Applications by Jeff Eerkens (University of Missouri), Jay Kunze (Idaho State University), and Leonard Bond (Idaho National Laboratory) The principal isotope enrichment business in the world is the enrichment of uranium for commercial power reactor fuels. However, there are a number of other needs for separated isotopes. Some examples are: 1) Pure isotopic targets for irradiation to produce medical radioisotopes. 2) Pure isotopes for semiconductors. 3) Low neutron capture isotopes for various uses in nuclear reactors. 4) Isotopes for industrial tracer/identification applications. Examples of interest to medicine are targets to produce radio-isotopes such as S-33, Mo-98, Mo-100, W-186, Sn-112; while for MRI diagnostics, the non-radioactive Xe-129 isotope is wanted. For super-semiconductor applications some desired industrial isotopes are Si-28, Ga-69, Ge-74, Se-80, Te-128, etc. An example of a low cross section isotope for use in reactors is Zn-68 as a corrosion inhibitor material in nuclear reactor primary systems. Neutron activation of Ar isotopes is of interest in industrial tracer and diagnostic applications (e.g. oil-logging). . In the past few years there has been a sufficient supply of isotopes in common demand, because of huge Russian stockpiles produced with old electromagnetic and centrifuge separators previously used for uranium enrichment. Production of specialized isotopes in the USA has been largely accomplished using old ”calutrons” (electromagnetic separators) at Oak Ridge National Laboratory. These methods of separating isotopes are rather energy inefficient. Use of lasers for isotope separation has been considered for many decades. None of the proposed methods have attained sufficient proof of principal status to be economically attractive to pursue commercially. Some of the authors have succeeded in separating sulfur isotopes using a rather new and different method, known as condensation

  19. Overview of recent studies and modifications being made to RHIC to mitigate the effects of a potential failure to the helium distribution system

    SciTech Connect (OSTI)

    Tuozzolo, J.; Bruno, D.; DiLieto, A.; Heppner, G.; Karol, R.; Lessard,E.; Liaw, C-J; McIntyre, G; Mi, C.; Reich, J.; Sandberg, J.; Seberg, S.; Smart, L.; Tallerico, T.; Theisen, C.; Todd, R.; Zapasek R.

    2011-03-28

    In order to cool the superconducting magnets in RHIC, its helium refrigerator distributes 4.5 K helium throughout the tunnel along with helium distribution for the magnet line recoolers, the heat shield, and the associated return lines. The worse case for failure would be a release from the magnet distribution line which operates at 3.5 to 4.5 atmospheres and contains the energized magnet but with a potential energy of 70 MJoules should the insulation system fail or an electrical connection opens. Studies were done to determine release rate of the helium and the resultant reduction in O{sub 2} concentration in the RHIC tunnel and service buildings. Equipment and components were also reviewed for design and reliability and modifications were made to reduce the likelihood of failure and to reduce the volume of helium that could be released.

  20. Strontium-isotope stratigraphy of Enewetak Atoll

    SciTech Connect (OSTI)

    Ludwig, K.R.; Halley, R.B.; Simmons, K.R.; Peterman, Z.E.

    1988-02-01

    /sup 87/Sr//sup 86/Sr ratios determined for samples from a 350 m core of Neogene lagoonal, shallow-water limestones from Enewetak Atoll display a remarkably informative trend. Like the recently published data for Deep Sea Drilling Project (DSDP) carbonates, /sup 87/Sr//sup 86/Sr at Enewetak increases monotonically but not smoothly from the early Miocene to the Pleistocene. The data show intervals of little or no change in /sup 87/Sr//sup 86/Sr, punctuated by sharp transitions to lower values toward greater core depths. The sharp transitions correlate with observed solution disconformities caused by periods of subaerial erosion, whereas the intervals of little or no change in /sup 87/Sr//sup 86/Sr correspond to intervals of rapid accumulation of shallow-water carbonate sediments. When converted to numerical ages using the published DSDP 590B trend, the best-resolved time breaks are at 282 m (12.3 to 18.2 Ma missing) and 121.6 m (3.0 to 5.3 Ma missing) below the lagoon floor. At Enewetak, Sr isotopes offer a stratigraphic resolution for these shallow-marine Neogene carbonates comparable to that of nannofossil zonation in deep-sea carbonates (0.3-3 m.y.). In addition, the correlation of times of Sr-isotope breaks at Enewetak with times of rapid Sr-isotope change in the DSDP 590B samples confirms the importance of sea-level changes in the evolution of global-marine Sr isotopes and shows that the Sr-isotope response to sea-level falls is rapid.

  1. Method of enhancing selective isotope desorption from metals

    DOE Patents [OSTI]

    Knize, Randall J. (Plainsboro, NJ); Cecchi, Joseph L. (Lawrenceville, NJ)

    1984-01-01

    A method of enhancing the thermal desorption of a first isotope of a diatomic gas from a metal comprises the steps of (a) establishing a partial pressure of a second isotope of the diatomic gas in vicinity of the metal; heating the metal to a temperature such that the first isotope is desorbed from the metal; and reducing the partial pressure of the desorbed first isotope while maintaining the partial pressure of the second isotope substantially constant. The method is especially useful for enhancing the desorption of tritium from the Zr-Al getter in a plasma confinement device.

  2. Enriching stable isotopes: Alternative use for Urenco technology

    SciTech Connect (OSTI)

    Rakhorst, H.; de Jong, P.G.T.; Dawson, P.D.

    1996-12-31

    The International Urenco Group utilizes a technologically advanced centrifuge process to enrich uranium in the fissionable isotope {sup 235}U. The group operates plants in the United Kingdom, the Netherlands, and Germany and currently holds a 10% share of the multibillion dollar world enrichment market. In the early 1990s, Urenco embarked on a strategy of building on the company`s uniquely advanced centrifuge process and laser isotope separation (LIS) experience to enrich nonradioactive isotopes colloquially known as stable isotopes. This paper summarizes the present status of Urenco`s stable isotopes business.

  3. Energy Perspectives: Trends and Milestones

    Reports and Publications (EIA)

    2011-01-01

    Energy Perspectives is a graphical overview of energy history in the United States. The 43 graphs shown here reveal sweeping trends related to the nation's production, consumption, and trade of energy from 1949 through 2011.

  4. Astrobiology: An astronomer's perspective

    SciTech Connect (OSTI)

    Bergin, Edwin A.

    2014-12-08

    In this review we explore aspects of the field of astrobiology from an astronomical viewpoint. We therefore focus on the origin of life in the context of planetary formation, with additional emphasis on tracing the most abundant volatile elements, C, H, O, and N that are used by life on Earth. We first explore the history of life on our planet and outline the current state of our knowledge regarding the delivery of the C, H, O, N elements to the Earth. We then discuss how astronomers track the gaseous and solid molecular carriers of these volatiles throughout the process of star and planet formation. It is now clear that the early stages of star formation fosters the creation of water and simple organic molecules with enrichments of heavy isotopes. These molecules are found as ice coatings on the solid materials that represent microscopic beginnings of terrestrial worlds. Based on the meteoritic and cometary record, the process of planet formation, and the local environment, lead to additional increases in organic complexity. The astronomical connections towards this stage are only now being directly made. Although the exact details are uncertain, it is likely that the birth process of star and planets likely leads to terrestrial worlds being born with abundant water and organics on the surface.

  5. Renewable Hydrogen: The Environmental Perspective

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

    Hydrogen: The Environmental Perspective Tyson Eckerle Energy Independence Now Delivering Renewable Hydrogen Workshop November 16 th , 2009. Energy Independence Now Why are we here? California Hydrogen Highway SB 1505 co-authors (w/ UCS) Hydrogen Advocates A consistent pro-hydrogen voice Renewable Hydrogen Environmental Perspective SB 1505 Opportunity Government role Harnessing the environmental community The Environmental Community Who are we talking about? NGOs, academics, customers, concerned

  6. THE ATOMIC WEIGHTS COMMISSION AND ISOTOPIC ABUNDANCE RATIO DETERMINATIONS.

    SciTech Connect (OSTI)

    HOLDEN, N.E.

    2005-08-07

    Following Thomson's discovery of stable isotopes in non-radioactive chemical elements, the derivation of atomic weight values from mass spectrometric measurements of isotopic abundance ratios moved very slowly. Forty years later, only 3 1/2 % of the recommended values were based on mass spectrometric measurements and only 38% in the first half century. It might be noted that two chemical elements (tellurium and mercury) are still based on chemical measurements, where the atomic weight value calculated from the relative isotopic abundance measurement either agrees with the value from the chemical measurement or the atomic weight value calculated from the relative isotopic abundance measurement falls within the uncertainty of the chemical measurement of the atomic weight. Of the 19 chemical elements, whose atomic weight is based on non-corrected relative isotopic abundance measurements, five of these are two isotope systems (indium, iridium, lanthanum, lutetium and tantalum) and one is a three-isotope system (oxygen).

  7. Method of preparing mercury with an arbitrary isotopic distribution

    DOE Patents [OSTI]

    Grossman, Mark W.; George, William A.

    1986-01-01

    This invention provides for a process for preparing mercury with a predetermined, arbitrary, isotopic distribution. In one embodiment, different isotopic types of Hg.sub.2 Cl.sub.2, corresponding to the predetermined isotopic distribution of Hg desired, are placed in an electrolyte solution of HCl and H.sub.2 O. The resulting mercurous ions are then electrolytically plated onto a cathode wire producing mercury containing the predetermined isotopic distribution. In a similar fashion, Hg with a predetermined isotopic distribution is obtained from different isotopic types of HgO. In this embodiment, the HgO is dissolved in an electrolytic solution of glacial acetic acid and H.sub.2 O. The isotopic specific Hg is then electrolytically plated onto a cathode and then recovered.

  8. Method of preparing mercury with an arbitrary isotopic distribution

    DOE Patents [OSTI]

    Grossman, M.W.; George, W.A.

    1986-12-16

    This invention provides for a process for preparing mercury with a predetermined, arbitrary, isotopic distribution. In one embodiment, different isotopic types of Hg[sub 2]Cl[sub 2], corresponding to the predetermined isotopic distribution of Hg desired, are placed in an electrolyte solution of HCl and H[sub 2]O. The resulting mercurous ions are then electrolytically plated onto a cathode wire producing mercury containing the predetermined isotopic distribution. In a similar fashion, Hg with a predetermined isotopic distribution is obtained from different isotopic types of HgO. In this embodiment, the HgO is dissolved in an electrolytic solution of glacial acetic acid and H[sub 2]O. The isotopic specific Hg is then electrolytically plated onto a cathode and then recovered. 1 fig.

  9. Flow instabilities in non-uniformly heated helium jet arrays used for divertor PFCs

    SciTech Connect (OSTI)

    Youchison, Dennis L.

    2015-07-30

    In this study, due to a lack of prototypical experimental data, little is known about the off-normal behavior of recently proposed divertor jet cooling concepts. This article describes a computational fluid dynamics (CFD) study on two jet array designs to investigate their susceptibility to parallel flow instabilities induced by non-uniform heating and large increases in the helium outlet temperature. The study compared a single 25-jet helium-cooled modular divertor (HEMJ) thimble and a micro-jet array with 116 jets. Both have pure tungsten armor and a total mass flow rate of 10 g/s at a 600 °C inlet temperature. We investigated flow perturbations caused by a 30 MW/m2 off-normal heat flux applied over a 25 mm2 area in addition to the nominal 5 MW/m2 applied over a 75 mm2 portion of the face. The micro-jet array exhibited lower temperatures and a more uniform surface temperature distribution than the HEMJ thimble. We also investigated the response of a manifolded nine-finger HEMJ assembly using the nominal heat flux and a 274 mm2 heated area. For the 30 MW/m2 case, the micro-jet array absorbed 750 W in the helium with a maximum armor surface temperature of 1280 °C and a fluid/solid interface temperature of 801 °C. The HEMJ absorbed 750 W with a maximum armor surface temperature of 1411 °C and a fluid/solid interface temperature of 844 °C. For comparison, both the single HEMJ finger and the micro-jet array used 5-mm-thick tungsten armor. The ratio of maximum to average temperature and variations in the local heat transfer coefficient were lower for the micro-jet array compared to the HEMJ device. Although high heat flux testing is required to validate the results obtained in these simulations, the results provide important guidance in jet design and manifolding to increase heat removal while providing more even temperature distribution and minimizing non-uniformity in the gas flow and thermal stresses at the

  10. Flow instabilities in non-uniformly heated helium jet arrays used for divertor PFCs

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

    Youchison, Dennis L.

    2015-07-30

    In this study, due to a lack of prototypical experimental data, little is known about the off-normal behavior of recently proposed divertor jet cooling concepts. This article describes a computational fluid dynamics (CFD) study on two jet array designs to investigate their susceptibility to parallel flow instabilities induced by non-uniform heating and large increases in the helium outlet temperature. The study compared a single 25-jet helium-cooled modular divertor (HEMJ) thimble and a micro-jet array with 116 jets. Both have pure tungsten armor and a total mass flow rate of 10 g/s at a 600 °C inlet temperature. We investigated flowmore » perturbations caused by a 30 MW/m2 off-normal heat flux applied over a 25 mm2 area in addition to the nominal 5 MW/m2 applied over a 75 mm2 portion of the face. The micro-jet array exhibited lower temperatures and a more uniform surface temperature distribution than the HEMJ thimble. We also investigated the response of a manifolded nine-finger HEMJ assembly using the nominal heat flux and a 274 mm2 heated area. For the 30 MW/m2 case, the micro-jet array absorbed 750 W in the helium with a maximum armor surface temperature of 1280 °C and a fluid/solid interface temperature of 801 °C. The HEMJ absorbed 750 W with a maximum armor surface temperature of 1411 °C and a fluid/solid interface temperature of 844 °C. For comparison, both the single HEMJ finger and the micro-jet array used 5-mm-thick tungsten armor. The ratio of maximum to average temperature and variations in the local heat transfer coefficient were lower for the micro-jet array compared to the HEMJ device. Although high heat flux testing is required to validate the results obtained in these simulations, the results provide important guidance in jet design and manifolding to increase heat removal while providing more even temperature distribution and minimizing non-uniformity in the gas flow and thermal stresses at the armor joint.« less

  11. The Helium Cooling System and Cold Mass Support System for theMICE Coupling Solenoid

    SciTech Connect (OSTI)

    Wang, L.; Wu, H.; Li, L.K.; Green, M.A.; Liu, C.S.; Li, L.Y.; Jia, L.X.; Virostek, S.P.

    2007-08-27

    The MICE cooling channel consists of alternating threeabsorber focus coil module (AFC) and two RF coupling coil module (RFCC)where the process of muon cooling and reacceleration occurs. The RFCCmodule comprises a superconducting coupling solenoid mounted around fourconventional conducting 201.25 MHz closed RF cavities and producing up to2.2T magnetic field on the centerline. The coupling coil magnetic fieldis to produce a low muon beam beta function in order to keep the beamwithin the RF cavities. The magnet is to be built using commercialniobium titanium MRI conductors and cooled by pulse tube coolers thatproduce 1.5 W of cooling capacity at 4.2 K each. A self-centering supportsystem is applied for the coupling magnet cold mass support, which isdesigned to carry a longitudinal force up to 500 kN. This report willdescribe the updated design for the MICE coupling magnet. The cold masssupport system and helium cooling system are discussed indetail.

  12. A modified heat leak test facility employing a closed-cycle helium refrigerator

    SciTech Connect (OSTI)

    Boroski, W.N.

    1996-01-01

    A Heat Leak Test Facility (HLTF) has been in use at Fermilab for many years. The apparatus has successfully measured the thermal performance of a variety of cryostat components under simulated operating conditions. While an effective tool in the cryostat design process, the HLTF has several limitations. Temperatures are normally fixed at cryogen boiling points and run times are limited to cryogen inventory. Moreover, close personnel attention is required to maintain system inventories and sustain system equilibrium. To provide longer measurement periods without perturbation and to minimize personnel interaction, a new heat leak measurement facility (HLTF-2) has been designed that incorporates a closed-cycle helium refrigerator. The two-stage refrigerator provides cooling to the various temperature stations of the HLTF while eliminating the need for cryogens. Eliminating cryogen inventories has resulted in a reduction of the amount of direct personnel attention required.

  13. Comparison of classical and quantal calculations of helium three-body recombination

    SciTech Connect (OSTI)

    Prez-Ros, Jess Greene, Chris H.; Ragole, Steve; Wang, Jia

    2014-01-28

    A general method to study classical scattering in n-dimension is developed. Through classical trajectory calculations, the three-body recombination is computed as a function of the collision energy for helium atoms, as an example. Quantum calculations are also performed for the J{sup ?} = 0{sup +} symmetry of the three-body recombination rate in order to compare with the classical results, yielding good agreement for E ? 1 K. The classical threshold law is derived and numerically confirmed for the Newtonian three-body recombination rate. Finally, a relationship is found between the quantum and classical three-body hard hypersphere elastic cross sections which is analogous to the well-known shadow scattering in two-body collisions.

  14. Numerical investigation of pulse-modulated atmospheric radio frequency discharges in helium under different duty cycles

    SciTech Connect (OSTI)

    Sun Jizhong; Ding Zhengfen; Li Xuechun; Wang Dezhen [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023 (China); Wang Qi [Dalian Institute of Semiconductor Technology, School of Electronics Science and Technology, Dalian University of Technology, Dalian 116023 (China)

    2011-12-15

    Experiments observed that the pulse duty cycle has effects on the plasma homogeneity in pulse-modulated radio frequency (rf) discharges. In this paper, pulse-modulated rf (13.56 MHz) helium discharges are theoretically investigated using a two dimensional fluid model. With the pulse period being fixed to 15 {mu}s, it is found that when the pulse-on duration is over 4 {mu}s, i.e., the duty cycle is larger than approximately 27%, the discharge transits from an inhomogeneous to a homogeneous mode in every specific part of each pulse cycle under currently-used simulation parameters. More quantitative analysis shows that the discharge becomes more homogeneous as the duty cycle is increased but does not reach complete homogeneity. Possible reasons for the homogeneity improvement are discussed.

  15. Commissioning and operational results of the 12 GeV helium compression system at Jlab

    SciTech Connect (OSTI)

    Knudsen, Peter N.; Ganni, Venkatarao; Dixon, Kelly D.; Norton, Robert O.; Creel, Jonathan D.

    2015-12-01

    The new compressor system at Jefferson Lab (JLab) for the 12 GeV upgrade was commissioned in the spring of 2013 and incorporates many design changes, discussed in previous publications, to improve the operational range, efficiency, reliability and maintainability as compared to previous compressor skids used for this application. The 12 GeV helium compression system has five compressors configured with four pressure levels supporting three pressure levels in the new cold box. During compressor commissioning the compressors were operated independent of the cold box over a wide range of process conditions to verify proper performance including adequate cooling and oil removal. Isothermal and volumetric efficiencies over these process conditions for several built-involume ratios were obtained. This paper will discuss the operational envelope results and the modifications/improvements incorporated into the skids.

  16. Fast Thermal Helium Beam diagnostic for measurements of edge electron profiles and fluctuations

    SciTech Connect (OSTI)

    Agostini, M. Scarin, P.; Cavazzana, R.; Carraro, L.; Grando, L.; Taliercio, C.; Franchin, L.; Tiso, A.

    2015-12-15

    The edge of fusion experiments is a region where strong gradients develop, together with the presence of strong fluctuations due to turbulence. The thermal helium beam diagnostic developed for the RFX-mod experiment allows the measurements with a single diagnostic of both low frequency time evolution of the edge radial profiles of electron density and temperature (tens of hertz), and the high frequency fluctuations (hundreds of kHz). To maximize the collected light, the three HeI lines necessary to be measured for the evaluation of n{sub e} and T{sub e} are separated with a spectrograph, and multianode photomultipliers are used as light detectors. The paper describes the diagnostic setup, with the interface hardware with the machine and the optical layout, and the characterization of its performances.

  17. First Principles Calculations of Helium Solution Energies in BCC Transition Metals

    SciTech Connect (OSTI)

    Willaime, Francois; Fu, Chu Chun

    2008-07-01

    Density functional theory calculations of the solution energies of helium in substitutional, tetrahedral and octahedral sites have been performed for all BCC transition metals: V, Nb, Ta, Cr, Mo, W and Fe. The effects of exchange correlation functional and of pseudopotential have been investigated in Fe; they are relatively small. The solution energies are found to be weakly dependent on the element for the substitutional site whereas for the interstitial sites they are much smaller in group V than in group VI and they decrease from 3d to 4d and 5d metals. As a result an inversion is observed from V, Nb and Ta - which tend to favor the interstitial site - to Mo and W, which favor the substitutional one, with an intermediate behavior for Cr and Fe. Finally, the results indicate that the tetrahedral site is always energetically more favorable than the octahedral one by 0.2 to 0.3 eV. (authors)

  18. Corrosion and Creep of Candidate Alloys in High Temperature Helium and Steam Environments for the NGNP

    SciTech Connect (OSTI)

    Was, Gary; Jones, J. W.

    2013-06-21

    This project aims to understand the processes by which candidate materials degrade in He and supercritical water/steam environments characteristic of the current NGNP design. We will focus on understanding the roles of temperature, and carbon and oxygen potential in the 750-850 degree C range on both uniform oxidation and selective internal oxidation along grain boundaries in alloys 617 and 800H in supercritical water in the temperature range 500-600 degree C; and examining the application of static and cyclic stresses in combination with impure He environments in the temperature rang 750-850 degree C; and examining the application of static and cyclic stresses in combination with impure He environments in the temperature range 750-850 degree C over a range of oxygen and carbon potentials in helium. Combined, these studies wil elucidate the potential high damage rate processes in environments and alloys relevant to the NGNP.

  19. High-voltage electrical apparatus utilizing an insulating gas of sulfur hexafluoride and helium

    DOE Patents [OSTI]

    Wootton, Roy E.

    1980-01-01

    High-voltage electrical apparatus includes an outer housing at low potential, an inner electrode disposed within the outer housing at high potential with respect thereto, and support means for insulatably supporting the inner electrode within the outer housing. Conducting particles contaminate the interior of the outer housing, and an insulating gas electrically insulates the inner electrode from the outer housing even in the presence of the conducting particles. The insulating gas is comprised of sulfur hexafluoride at a partial pressure of from about 2.9 to about 3.4 atmospheres absolute, and helium at a partial pressure from about 1.1 to about 11.4 atmospheres absolute. The sulfur hexafluoride comprises between 20 and 65 volume percent of the insulating gas.

  20. Impurity gettering in silicon using cavities formed by helium implantation and annealing

    DOE Patents [OSTI]

    Myers, S.M. Jr.; Bishop, D.M.; Follstaedt, D.M.

    1998-11-24

    Impurity gettering in silicon wafers is achieved by a new process consisting of helium ion implantation followed by annealing. This treatment creates cavities whose internal surfaces are highly chemically reactive due to the presence of numerous silicon dangling bonds. For two representative transition-metal impurities, copper and nickel, the binding energies at cavities were demonstrated to be larger than the binding energies in precipitates of metal silicide, which constitutes the basis of most current impurity gettering. As a result the residual concentration of such impurities after cavity gettering is smaller by several orders of magnitude than after precipitation gettering. Additionally, cavity gettering is effective regardless of the starting impurity concentration in the wafer, whereas precipitation gettering ceases when the impurity concentration reaches a characteristic solubility determined by the equilibrium phase diagram of the silicon-metal system. The strong cavity gettering was shown to induce dissolution of metal-silicide particles from the opposite side of a wafer. 4 figs.

  1. Impurity gettering in silicon using cavities formed by helium implantation and annealing

    DOE Patents [OSTI]

    Myers, Jr., Samuel M.; Bishop, Dawn M.; Follstaedt, David M.

    1998-01-01

    Impurity gettering in silicon wafers is achieved by a new process consisting of helium ion implantation followed by annealing. This treatment creates cavities whose internal surfaces are highly chemically reactive due to the presence of numerous silicon dangling bonds. For two representative transition-metal impurities, copper and nickel, the binding energies at cavities were demonstrated to be larger than the binding energies in precipitates of metal silicide, which constitutes the basis of most current impurity gettering. As a result the residual concentration of such impurities after cavity gettering is smaller by several orders of magnitude than after precipitation gettering. Additionally, cavity gettering is effective regardless of the starting impurity concentration in the wafer, whereas precipitation gettering ceases when the impurity concentration reaches a characteristic solubility determined by the equilibrium phase diagram of the silicon-metal system. The strong cavity gettering was shown to induce dissolution of metal-silicide particles from the opposite side of a wafer.

  2. Electron dynamics and plasma jet formation in a helium atmospheric pressure dielectric barrier discharge jet

    SciTech Connect (OSTI)

    Algwari, Q. Th.; O'Connell, D.

    2011-09-19

    The excitation dynamics within the main plasma production region and the plasma jets of a kHz atmospheric pressure dielectric barrier discharge (DBD) jet operated in helium was investigated. Within the dielectric tube, the plasma ignites as a streamer-type discharge. Plasma jets are emitted from both the powered and grounded electrode end; their dynamics are compared and contrasted. Ignition of these jets are quite different; the jet emitted from the powered electrode is ignited with a slight time delay to plasma ignition inside the dielectric tube, while breakdown of the jet at the grounded electrode end is from charging of the dielectric and is therefore dependent on plasma production and transport within the dielectric tube. Present streamer theories can explain these dynamics.

  3. Patterned Exfoliation of GaAs Based on Masked Helium Implantation and Subsequent Rapid Thermal Annealing

    SciTech Connect (OSTI)

    Woo, H. J.; Choi, H. W.; Kim, G. D.; Hong, W.; Kim, J. K.

    2009-03-10

    A method of patterning single crystal GaAs based on ion implantation induced selective area exfoliation is suggested. Samples were implanted with 200-500 keV helium ions to a fluence range of 2-4x10{sup 16} He{sup +}/cm{sup 2} at room temperature through masks of Ni mesh (40 {mu}m opening) or stainless steel wire (50 {mu}m in diameter), and subsequent rapid thermal annealing at 350-500{open_square} resulted in expulsion of ion beam exposed material. The influences of ion energy, ion fluence, implantation temperature, subsequent annealing conditions (temperature and ramp rate), and mask pattern and its orientation with GaAs lattice on the patterned exfoliation were examined.

  4. Transient analysis of an FHR coupled to a helium Brayton power cycle

    SciTech Connect (OSTI)

    Chen, Minghui; Kim, In Hun; Sun, Xiaodong; Christensen, Richard; Utgikar, Vivek; Sabharwall, Piyush

    2015-08-01

    The Fluoride salt-cooled High-temperature Reactor (FHR) features a passive decay heat removal system and a high-efficiency Brayton cycle for electricity generation. It typically employs an intermediate loop, consisting of an intermediate heat exchanger (IHX) and a secondary heat exchanger (SHX), to couple the primary system with the power conversion unit (PCU). In this study, a preliminary dynamic system model is developed to simulate transient characteristics of a prototypic 20-MWth Fluoride salt-cooled High-temperature Test Reactor (FHTR). The model consists of a series of differential conservation equations that are numerically solved using the MATLAB platform. For the reactor, a point neutron kinetics model is adopted. For the IHX and SHX, a fluted tube heat exchanger and an offset strip-fin heat exchanger are selected, respectively. Detailed geometric parameters of each component in the FHTR are determined based on the FHTR nominal steady-state operating conditions. Three initiating events are simulated in this study, including a positive reactivity insertion, a step increase in the mass flow rate of the PCU helium flow, and a step increase in the PCU helium inlet temperature to the SHX. The simulation results show that the reactor has inherent safety features for those three simulated scenarios. It is observed that the increase in the temperatures of the fuel pebbles and primary coolant is mitigated by the decrease in the reactor power due to negative temperature feedbacks. The results also indicate that the intermediate loop with the two heat exchangers plays a significant role in the transient progression of the integral reactor system.

  5. Solvation of molecules in superfluid helium enhances the interaction induced localization effect

    SciTech Connect (OSTI)

    Walewski, ?ukasz Forbert, Harald; Marx, Dominik

    2014-04-14

    Atomic nuclei become delocalized at low temperatures as a result of quantum effects, whereas they are point-like in the high temperature (classical) limit. For non-interacting nuclei, the delocalization upon lowering the temperature is quantitatively described in terms of the thermal de Broglie wavelength of free particles. Clearly, light non-interacting nuclei the proton being a prominent one are much more delocalized at low temperatures compared to heavy nuclei, such as non-interacting oxygen having water in mind. However, strong interactions due to chemical bonding in conjunction with ultra-low temperatures characteristic to superfluid helium nanodroplets change this common picture substantially for nuclei in molecules or clusters. It turns out that protons shared in hydrogen bonds undergo an extreme interaction induced localization at temperatures on the order of 1 K, which compresses the protonic spatial distributions to the size of the much heavier donor or acceptor atoms, such as O or Cl nuclei, corresponding to about 0.1% of the volume occupied by a non-interacting proton at the same temperature. Moreover, applying our recently developed hybrid ab initio path integral molecular dynamics/bosonic path integral Monte Carlo quantum simulation technique to a HCl/water cluster, HCl(H{sub 2}O){sub 4}, we find that helium solvation has a significant additional localizing effect of up to about 30% in volume. In particular, the solvent-induced excess localization is the stronger the lesser the given nucleus is already localized in the gas phase reference situation.

  6. Investigating the dynamics of laser induced sparks in atmospheric helium using Rayleigh and Thomson scattering

    SciTech Connect (OSTI)

    Nedanovska, E.; Nersisyan, G.; Lewis, C. L. S.; Riley, D.; Graham, W. G.; Morgan, T. J.; Hüwel, L.; Murakami, T.

    2015-01-07

    We have used optical Rayleigh and Thomson scattering to investigate the expansion dynamics of laser induced plasma in atmospheric helium and to map its electron parameters both in time and space. The plasma is created using 9 ns duration, 140 mJ pulses from a Nd:YAG laser operating at 1064 nm, focused with a 10 cm focal length lens, and probed with 7 ns, 80 mJ, and 532 nm Nd:YAG laser pulses. Between 0.4 μs and 22.5 μs after breakdown, the electron density decreases from 3.3 × 10{sup 17 }cm{sup −3} to 9 × 10{sup 13 }cm{sup −3}, while the temperature drops from 3.2 eV to 0.1 eV. Spatially resolved Thomson scattering data recorded up to 17.5 μs reveal that during this time the laser induced plasma expands at a rate given by R ∼ t{sup 0.4} consistent with a non-radiative spherical blast wave. This data also indicate the development of a toroidal structure in the lateral profile of both electron temperature and density. Rayleigh scattering data show that the gas density decreases in the center of the expanding plasma with a central scattering peak reemerging after about 12 μs. We have utilized a zero dimensional kinetic global model to identify the dominant particle species versus delay time and this indicates that metastable helium and the He{sub 2}{sup +} molecular ion play an important role.

  7. Hydrogen isotopic exchange over palladium metal

    SciTech Connect (OSTI)

    Carstens, D.H.W.; Encinias, P.D.

    1990-01-01

    We have recently developed the laser-Raman technique as a means of unambiguously measuring the partial pressures of all possible hydrogen isotopes in the gas phase. Using this technique we have investigated the hydrogen-deuterium exchange in a number of metals. This report presents detailed data for isotopic exchange in the palladium hydride system over the temperature range 26{degree}C to -100{degree}C at a pressure of 7 atm. First order kinetic rate constants and activation energies are summarized for the forward (hydride to deuteride) and reverse (deuteride to hydride) exchange processes. In addition, we have found that small amounts (100 ppm) of impurities in the exchange gases considerably slow the exchange kinetics with the effect increasing down the series CH{sub 4}, CO{sub 2}, H{sub 2}O, and CO. 9 refs., 4 figs., 1 tab.

  8. Regioselective synthesis using the deuterium isotope effect

    SciTech Connect (OSTI)

    Miyano, M.

    1981-04-24

    Dehydration of 1a by various procedures invariably produced more exo olefin 2a than endo olefin 3a. This could be reversed by introduction of deuterium in the Me-21 group of the starting material. Thus, dehydration of 1b could afford more endo olefin 3b than exo olefin 2b due to the deuterium isotope effect. A regioselective synthesis of 18-oxoprogesterone (15a) from 3..beta..-hydroxypregn-5-en-20-one (5a) was carried out taking advantage of the deuterium isotope effect as depicted in Scheme I. The key steps were dehydration of 7b to predominantly endo olefin 9b and removal of the deuteriums from 18-oxoprogesterone-17..cap alpha..,21,21,21-d/sub 4/ (15b) to give 15a.

  9. Quantifying uncertainty in stable isotope mixing models

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

    Davis, Paul; Syme, James; Heikoop, Jeffrey; Fessenden-Rahn, Julianna; Perkins, George; Newman, Brent; Chrystal, Abbey E.; Hagerty, Shannon B.

    2015-05-19

    Mixing models are powerful tools for identifying biogeochemical sources and determining mixing fractions in a sample. However, identification of actual source contributors is often not simple, and source compositions typically vary or even overlap, significantly increasing model uncertainty in calculated mixing fractions. This study compares three probabilistic methods, SIAR [Parnell et al., 2010] a pure Monte Carlo technique (PMC), and Stable Isotope Reference Source (SIRS) mixing model, a new technique that estimates mixing in systems with more than three sources and/or uncertain source compositions. In this paper, we use nitrate stable isotope examples (δ15N and δ18O) but all methods testedmore » are applicable to other tracers. In Phase I of a three-phase blind test, we compared methods for a set of six-source nitrate problems. PMC was unable to find solutions for two of the target water samples. The Bayesian method, SIAR, experienced anchoring problems, and SIRS calculated mixing fractions that most closely approximated the known mixing fractions. For that reason, SIRS was the only approach used in the next phase of testing. In Phase II, the problem was broadened where any subset of the six sources could be a possible solution to the mixing problem. Results showed a high rate of Type I errors where solutions included sources that were not contributing to the sample. In Phase III some sources were eliminated based on assumed site knowledge and assumed nitrate concentrations, substantially reduced mixing fraction uncertainties and lowered the Type I error rate. These results demonstrate that valuable insights into stable isotope mixing problems result from probabilistic mixing model approaches like SIRS. The results also emphasize the importance of identifying a minimal set of potential sources and quantifying uncertainties in source isotopic composition as well as demonstrating the value of additional information in reducing the uncertainty in calculated

  10. Optically pumped isotopic ammonia laser system

    DOE Patents [OSTI]

    Buchwald, Melvin I.; Jones, Claude R.; Nelson, Leonard Y.

    1982-01-01

    An optically pumped isotopic ammonia laser system which is capable of producing a plurality of frequencies in the middle infrared spectral region. Two optical pumping mechanisms are disclosed, i.e., pumping on R(J) and lasing on P(J) in response to enhancement of rotational cascade lasing including stimulated Raman effects, and, pumping on R(J) and lasing on P(J+2). The disclosed apparatus for optical pumping include a hole coupled cavity and a grating coupled cavity.

  11. Stable isotopic analyses in paleoclimatic reconstruction

    SciTech Connect (OSTI)

    Wigand, P.E.

    1995-09-01

    Most traditional paleoclimatic proxy data have inherent time lags between climatic input and system response that constrain their use in accurate reconstruction of paleoclimate chronology, scaling of its variability, and the elucidation of the processes that determine its impact on the biotic and abiotic environment. With the exception of dendroclimatology, and studies of short-lived organisms and pollen recovered from annually varved lacustrine sediments, significant periods of time ranging from years, to centuries, to millennia may intervene between climate change and its first manifestation in paleoclimatic proxy data records. Reconstruction of past climate through changes in plant community composition derived from pollen sequences and plant remains from ancient woodrat middens, wet environments and dry caves all suffer from these lags. However, stable isotopic analyses can provide more immediate indication of biotic response to climate change. Evidence of past physiological response of organisms to changes in effective precipitation as climate varies can be provided by analyses of the stable isotopic content of plant macrofossils from various contexts. These analyses consider variation in the stable isotopic (hydrogen, oxygen and carbon) content of plant tissues as it reflects (1) past global or local temperature through changes in meteoric (rainfall) water chemistry in the case of the first two isotopes, and (2) plant stress through changes in plant respiration/transpiration processes under differing water availability, and varying atmospheric CO, composition (which itself may actually be a net result of biotic response to climate change). Studies currently being conducted in the Intermountain West indicate both long- and short-term responses that when calibrated with modem analogue studies have the potential of revealing not only the timing of climate events, but their direction, magnitude and rapidity.

  12. Separation of uranium isotopes by chemical exchange

    DOE Patents [OSTI]

    Ogle, P.R. Jr.

    1974-02-26

    A chemical exchange method is provided for separating /sup 235/U from / sup 238/U comprising contacting a first phase containing UF/sub 6/ with a second phase containing a compound selected from the group consisting of NOUF/sub 6/, NOUF/sub 7/, and NO/sub 2/UF/sub 7/ until the U Fsub 6/ in the first phase becomes enriched in the /sup 235/U isotope. (Official Gazette)

  13. Quantifying uncertainty in stable isotope mixing models

    SciTech Connect (OSTI)

    Davis, Paul; Syme, James; Heikoop, Jeffrey; Fessenden-Rahn, Julianna; Perkins, George; Newman, Brent; Chrystal, Abbey E.; Hagerty, Shannon B.

    2015-05-19

    Mixing models are powerful tools for identifying biogeochemical sources and determining mixing fractions in a sample. However, identification of actual source contributors is often not simple, and source compositions typically vary or even overlap, significantly increasing model uncertainty in calculated mixing fractions. This study compares three probabilistic methods, SIAR [Parnell et al., 2010] a pure Monte Carlo technique (PMC), and Stable Isotope Reference Source (SIRS) mixing model, a new technique that estimates mixing in systems with more than three sources and/or uncertain source compositions. In this paper, we use nitrate stable isotope examples (?15N and ?18O) but all methods tested are applicable to other tracers. In Phase I of a three-phase blind test, we compared methods for a set of six-source nitrate problems. PMC was unable to find solutions for two of the target water samples. The Bayesian method, SIAR, experienced anchoring problems, and SIRS calculated mixing fractions that most closely approximated the known mixing fractions. For that reason, SIRS was the only approach used in the next phase of testing. In Phase II, the problem was broadened where any subset of the six sources could be a possible solution to the mixing problem. Results showed a high rate of Type I errors where solutions included sources that were not contributing to the sample. In Phase III some sources were eliminated based on assumed site knowledge and assumed nitrate concentrations, substantially reduced mixing fraction uncertainties and lowered the Type I error rate. These results demonstrate that valuable insights into stable isotope mixing problems result from probabilistic mixing model approaches like SIRS. The results also emphasize the importance of identifying a minimal set of potential sources and quantifying uncertainties in source isotopic composition as well as demonstrating the value of additional information in reducing the

  14. Quantifying uncertainty in stable isotope mixing models

    SciTech Connect (OSTI)

    Davis, Paul; Syme, James; Heikoop, Jeffrey; Fessenden-Rahn, Julianna; Perkins, George; Newman, Brent; Chrystal, Abbey E.; Hagerty, Shannon B.

    2015-05-19

    Mixing models are powerful tools for identifying biogeochemical sources and determining mixing fractions in a sample. However, identification of actual source contributors is often not simple, and source compositions typically vary or even overlap, significantly increasing model uncertainty in calculated mixing fractions. This study compares three probabilistic methods, SIAR [Parnell et al., 2010] a pure Monte Carlo technique (PMC), and Stable Isotope Reference Source (SIRS) mixing model, a new technique that estimates mixing in systems with more than three sources and/or uncertain source compositions. In this paper, we use nitrate stable isotope examples (δ15N and δ18O) but all methods tested are applicable to other tracers. In Phase I of a three-phase blind test, we compared methods for a set of six-source nitrate problems. PMC was unable to find solutions for two of the target water samples. The Bayesian method, SIAR, experienced anchoring problems, and SIRS calculated mixing fractions that most closely approximated the known mixing fractions. For that reason, SIRS was the only approach used in the next phase of testing. In Phase II, the problem was broadened where any subset of the six sources could be a possible solution to the mixing problem. Results showed a high rate of Type I errors where solutions included sources that were not contributing to the sample. In Phase III some sources were eliminated based on assumed site knowledge and assumed nitrate concentrations, substantially reduced mixing fraction uncertainties and lowered the Type I error rate. These results demonstrate that valuable insights into stable isotope mixing problems result from probabilistic mixing model approaches like SIRS. The results also emphasize the importance of identifying a minimal set of potential sources and quantifying uncertainties in source isotopic composition as well as demonstrating the value of additional information in reducing the

  15. Concerning the Facility for Rare Isotope Beams

    ScienceCinema (OSTI)

    Symons, James

    2013-05-29

    James Symons, Nuclear Science Division Director at Lawrence Berkeley Lab, and Daniela Leitner, head of operations at Berkeley Lab's 88-Inch Cyclotron, discuss major contributions to the new Facility for Rare Isotope Beams (FRIB) at Michigan State University, including ion source, which will based on the VENUS source built for the 88-Inch Cyclotron, and the GRETA gamma-ray detector now under construction there.

  16. Trapping helium in Y{sub 2}Ti{sub 2}O{sub 7} compared to in matrix iron: A first principles study

    SciTech Connect (OSTI)

    Yang, Litong; Jiang, Yong E-mail: odette@engineering.ucsb.edu; Robert Odette, G. E-mail: odette@engineering.ucsb.edu; Yamamoto, Takuya; Liu, Zuming; Liu, Yong

    2014-04-14

    Pyrochlore Y{sub 2}Ti{sub 2}O{sub 7} is a primary precipitate phase in nano-structured ferritic alloys (NFAs) for fission and fusion energy applications. We report a theoretical study for assessing the relative stability of trapping helium in Y{sub 2}Ti{sub 2}O{sub 7} versus in matrix iron. Various defect structures and the associated energies are examined and compared. Results reveal that helium can be deeply trapped in Y{sub 2}Ti{sub 2}O{sub 7} and that the corresponding self-interaction is essentially repulsive. Transmutant helium in NFAs prefers to occupy individual octa-interstitial sites in Y{sub 2}Ti{sub 2}O{sub 7}, before forming small clusters in Y{sub 2}Ti{sub 2}O{sub 7}. Helium partitioning in NFAs depends on the number and dispersion of Y{sub 2}Ti{sub 2}O{sub 7}; and thus initially, bubble formation and growth in iron matrix can be largely suppressed. Charge transfer occurs from helium to neighboring oxygen anions, but not to neighboring metal cations, suggesting a general effectiveness of trapping helium in oxides. Reasons for the ultimate fate of helium to form small nm-scale interface bubbles are also discussed.

  17. Isotopic noble gas signatures released from medical isotope production facilities - Simulations and measurements

    SciTech Connect (OSTI)

    Saey, Paul R.; Bowyer, Ted W.; Ringbom, Anders

    2010-09-09

    Journal article on the role that radioxenon isotopes play in confirming whether or not an underground explosion was nuclear in nature. Radioxenon isotopes play a major role in confirming whether or not an underground explosion was nuclear in nature. It is then of key importance to understand the sources of environmental radioxenon to be able to distinguish civil sources from those of a nuclear explosion. Based on several years of measurements, combined with advanced atmospheric transport model results, it was recently shown that the main source of radioxenon observations are strong and regular batch releases from a very limited number of medical isotope production facilities. This paper reviews production processes in different medical isotope facilities during which radioxenon is produced. Radioxenon activity concentrations and isotopic compositions are calculated for six large facilities. The results are compared with calculated signals from nuclear explosions. Further, the outcome is compared and found to be consistent with radioxenon measurements recently performed in and around three of these facilities. Some anomalies in measurements in which {sup 131m}Xe was detected were found and a possible explanation is proposed. It was also calculated that the dose rate of the releases is well below regulatory values. Based on these results, it should be possible to better understand, interpret and verify signals measured in the noble gas measurement systems in the International Monitoring of the Comprehensive Nuclear-Test-Ban Treaty.

  18. First AID (Atom counting for Isotopic Determination).

    SciTech Connect (OSTI)

    Roach, J. L.; Israel, K. M.; Steiner, R. E.; Duffy, C. J.; Roench, F. R.

    2002-01-01

    Los Alamos National Laboratory (LANL) has established an in vitro bioassay monitoring program in compliance with the requirements in the Code of Federal Regulations, 10 CFR 835, Occupational Radiation Protection. One aspect of this program involves monitoring plutonium levels in at-risk workers. High-risk workers are monitored using the ultra-sensitive Therrnal Ionization Mass Spectrometry (TIMS) technique to ensure compliance with DOE standards. TIMS is used to measure atom ratios of 239Pua nd 240Puw ith respect to a tracer isotope ('Pu). These ratios are then used to calculate the amount of 239Pu and 240Pup resent. This low-level atom counting technique allows the calculation of the concentration levels of 239Pu and 240Pu in urine for at risk workers. From these concentration levels, dose assessments can be made and worker exposure levels can be monitored. Detection limits for TIMS analysis are on the order of millions of atoms, which translates to activity levels of 150 aCi 239Pua nd 500 aCi for 240Pu. pCi for Our poster presentation will discuss the ultra-sensitive, low-level analytical technique used to measure plutonium isotopes and the data verification methods used for validating isotopic measurements.

  19. Hydrogen isotope separation utilizing bulk getters

    DOE Patents [OSTI]

    Knize, Randall J. (Los Angeles, CA); Cecchi, Joseph L. (Lawrenceville, NJ)

    1990-01-01

    Tritium and deuterium are separated from a gaseous mixture thereof, derived from a nuclear fusion reactor or some other source, by providing a casing with a bulk getter therein for absorbing the gaseous mixture to produce an initial loading of the getter, partially desorbing the getter to produce a desorbed mixture which is tritium-enriched, pumping the desorbed mixture into a separate container, the remaining gaseous loading in the getter being deuterium-enriched, desorbing the getter to a substantially greater extent to produce a deuterium-enriched gaseous mixture, and removing the deuterium-enriched mixture into another container. The bulk getter may comprise a zirconium-aluminum alloy, or a zirconium-vanadium-iron alloy. The partial desorption may reduce the loading by approximately fifty percent. The basic procedure may be extended to produce a multistage isotope separator, including at least one additional bulk getter into which the tritium-enriched mixture is absorbed. The second getter is then partially desorbed to produce a desorbed mixture which is further tritium-enriched. The last-mentioned mixture is then removed from the container for the second getter, which is then desorbed to a substantially greater extent to produce a desorbed mixture which is deuterium-enriched. The last-mentioned mixture is then removed so that the cycle can be continued and repeated. The method of isotope separation is also applicable to other hydrogen isotopes, in that the method can be employed for separating either deuterium or tritium from normal hydrogen.

  20. Hydrogen isotope separation utilizing bulk getters

    DOE Patents [OSTI]

    Knize, Randall J. (Los Angeles, CA); Cecchi, Joseph L. (Lawrenceville, NJ)

    1991-01-01

    Tritium and deuterium are separated from a gaseous mixture thereof, derived from a nuclear fusion reactor or some other source, by providing a casing with a bulk getter therein for absorbing the gaseous mixture to produce an initial loading of the getter, partially desorbing the getter to produce a desorbed mixture which is tritium-enriched, pumping the desorbed mixture into a separate container, the remaining gaseous loading in the getter being deuterium-enriched, desorbing the getter to a substantially greater extent to produce a deuterium-enriched gaseous mixture, and removing the deuterium-enriched mixture into another container. The bulk getter may comprise a zirconium-aluminum alloy, or a zirconium-vanadium-iron alloy. The partial desorption may reduce the loading by approximately fifty percent. The basic procedure may be extended to produce a multistage isotope separator, including at least one additional bulk getter into which the tritium-enriched mixture is absorbed. The second getter is then partially desorbed to produce a desorbed mixture which is further tritium-enriched. The last-mentioned mixture is then removed from the container for the second getter, which is then desorbed to a substantially greater extent to produce a desorbed mixture which is deuterium-enriched. The last-mentioned mixture is then removed so that the cycle can be continued and repeated. The method of isotope separation is also applicable to other hydrogen isotopes, in that the method can be employed for separating either deuterium or tritium from normal hydrogen.

  1. FILTR: Flash Isotope Library and Training Resource

    SciTech Connect (OSTI)

    Campbell, D; Trombino, D

    2007-07-26

    The subject of radiation detection is replete with complex concepts and challenging nomenclature. Furthermore, a daunting variety of radioactive isotopes may be encountered during the routine operation of a radiation detector. Individuals tasked with searching for illicit sources of radiation must remain vigilant while navigating through more frequently encountered mundane and legitimate radioactive sources. The Flash Isotope Library and Training Resource (FILTR) is being developed as an easily accessible and intuitive reference tool to manage the high volume of complex information required for this task. FILTR is an extended version of the Primary Utility for Nuclear Terminology (PUNT) software developed by the Counter Measures Test Beds group at Lawrence Livermore National Laboratory for the United States Secret Service. Authored in the Flash multimedia development environment, FILTR contains detailed information on potentially encountered isotopes as well as training on radiation and operational procedures. Reference material is organized to present critical information quickly while facilitating more in-depth investigation through an intuitive interface and engaging content. FILTR is being developed for a diverse audience of law enforcement organizations and government agencies and a wide range of skill sets from expert analysts to officers whose primary role is not radiation detection. Additionally, the wide compatibility of Flash content will allow FILTR to be readily accessible through the growing number of multi-media enabled electronic devices, including PDAs and cellular phones.

  2. Hydrogen isotope separation utilizing bulk getters

    DOE Patents [OSTI]

    Knize, R.J.; Cecchi, J.L.

    1991-08-20

    Tritium and deuterium are separated from a gaseous mixture thereof, derived from a nuclear fusion reactor or some other source, by providing a casing with a bulk getter therein for absorbing the gaseous mixture to produce an initial loading of the getter, partially desorbing the getter to produce a desorbed mixture which is tritium-enriched, pumping the desorbed mixture into a separate container, the remaining gaseous loading in the getter being deuterium-enriched, desorbing the getter to a substantially greater extent to produce a deuterium-enriched gaseous mixture, and removing the deuterium-enriched mixture into another container. The bulk getter may comprise a zirconium-aluminum alloy, or a zirconium-vanadium-iron alloy. The partial desorption may reduce the loading by approximately fifty percent. The basic procedure may be extended to produce a multistage isotope separator, including at least one additional bulk getter into which the tritium-enriched mixture is absorbed. The second getter is then partially desorbed to produce a desorbed mixture which is further tritium-enriched. The last-mentioned mixture is then removed from the container for the second getter, which is then desorbed to a substantially greater extent to produce a desorbed mixture which is deuterium-enriched. The last-mentioned mixture is then removed so that the cycle can be continued and repeated. The method of isotope separation is also applicable to other hydrogen isotopes, in that the method can be employed for separating either deuterium or tritium from normal hydrogen. 4 figures.

  3. U.S. Department of Energy Isotope Program

    SciTech Connect (OSTI)

    2015-06-23

    The National Isotope Development Center (NIDC) interfaces with the User Community and manages the coordination of isotope production across the facilities and business operations involved in the production, sale, and distribution of isotopes. A virtual center, the NIDC is funded by the Isotope Development and Production for Research and Applications (IDPRA) subprogram of the Office of Nuclear Physics in the U.S. Department of Energy Office of Science. PNNL’s Isotope Program operates in a multi-program category-2 nuclear facility, the Radiochemical Processing Laboratory (RPL), that contains 16 hot cells and 20 gloveboxes. As part of the DOE Isotope Program, the Pacific Northwest National Laboratory dispenses strontium-90, neptunium-237, radium-223, and thorium-227. PNNL’s Isotope Program uses a dedicated hot-cell for strontium-90 dispensing and a dedicated glovebox for radium-223 and thorium-227 dispensing. PNNL’s Isotope Program has access to state of the art analytical equipment in the RPL to support their research and production activities. DOE Isotope Program funded research at PNNL has advanced the application of automated radiochemistry for isotope such as zirconium-89 and astatine-211 in partnership with the University of Washington.

  4. Diffusional exchange of isotopes in a metal hydride sphere.

    SciTech Connect (OSTI)

    Wolfer, Wilhelm G.; Hamilton, John C.; James, Scott Carlton

    2011-04-01

    This report describes the Spherical Particle Exchange Model (SPEM), which simulates exchange of one hydrogen isotope by another hydrogen isotope in a spherical metal hydride particle. This is one of the fundamental physical processes during isotope exchange in a bed of spherical metal particles and is thus one of the key components in any comprehensive physics-based model of exchange. There are two important physical processes in the model. One is the entropy of mixing between the two isotopes; the entropy of mixing is increased by having both isotopes randomly placed at interstitial sites on the lattice and thus impedes the exchange process. The other physical process is the elastic interaction between isotope atoms on the lattice. The elastic interaction is the cause for {beta}-phase formation and is independent of the isotope species. In this report the coupled diffusion equations for two isotopes in the {beta}-phase hydride are solved. A key concept is that the diffusion of one isotope depends not only on its concentration gradient, but also on the concentration gradient of the other isotope. Diffusion rate constants and the chemical potentials for deuterium and hydrogen in the {beta}-phase hydride are reviewed because these quantities are essential for an accurate model of the diffusion process. Finally, a summary of some of the predictions from the SPEM model are provided.

  5. Isotope shifts in francium isotopes Fr 206 - 213 and Fr 221

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

    Collister, R.; Gwinner, G.; Tandecki, M.; Behr, J. A.; Pearson, M. R.; Zhang, J.; Orozco, L. A.; Aubin, S.; Gomez, E.; FrPNC Collaboration

    2014-11-07

    We present the isotope shifts of the 7s1/2 to 7p1/2 transition for francium isotopes ²⁰⁶⁻²¹³Fr with reference to ²²¹Fr collected from two experimental periods. The shifts are measured on a sample of atoms prepared within a magneto-optical trap by a fast sweep of radio-frequency sidebands applied to a carrier laser. King plot analysis, which includes literature values for 7s1/2 to 7p3/2 isotope shifts, provides a field shift constant ratio of 1.0520(10) and a difference between the specific mass shift constants of 170(100) GHz amu between the D₁ and D₂ transitions, of sufficient precision to differentiate between ab initio calculations.

  6. 2013 Wall Street Perspective on SMRs | Department of Energy

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

    Wall Street Perspective on SMRs 2013 Wall Street Perspective on SMRs Summary of results of a 2013 survey on Wall Street attitudes toward small modular reactors. 2013 Wall Street Perspective on SMRs (597.12 KB) More Documents & Publications 2014 Wall Street Perspectives on SMRs - Report 2014 Wall Street Perspective on SMRs 2015 Wall Street Perspectives on SMRs Update

  7. Perspectives GmbH | Open Energy Information

    Open Energy Info (EERE)

    Perspectives GmbH Jump to: navigation, search Name: Perspectives GmbH Place: Hamburg, Germany Zip: 22045 Product: Germany-based consultancy focusing on CDMJI projects as well as...

  8. Advances in Hydrogen Isotope Separation Using Thermal Cycling Absorption

    Office of Environmental Management (EM)

    Process (TCAP) | Department of Energy Hydrogen Isotope Separation Using Thermal Cycling Absorption Process (TCAP) Advances in Hydrogen Isotope Separation Using Thermal Cycling Absorption Process (TCAP) Presentation from the 32nd Tritium Focus Group Meeting held in Germantown, Maryland on April 23-25, 2013. Advances in Hydrogen Isotope Separation Using Thermal Cycling Absorption Process (TCAP) (1.74 MB) More Documents & Publications A New Hydrogen Processing Demonstration System Initial

  9. System and method for high precision isotope ratio destructive analysis

    DOE Patents [OSTI]

    Bushaw, Bruce A; Anheier, Norman C; Phillips, Jon R

    2013-07-02

    A system and process are disclosed that provide high accuracy and high precision destructive analysis measurements for isotope ratio determination of relative isotope abundance distributions in liquids, solids, and particulate samples. The invention utilizes a collinear probe beam to interrogate a laser ablated plume. This invention provides enhanced single-shot detection sensitivity approaching the femtogram range, and isotope ratios that can be determined at approximately 1% or better precision and accuracy (relative standard deviation).

  10. Isotope production facility produces cancer-fighting actinium

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

    Cancer therapy gets a boost from new isotope Isotope production facility produces cancer-fighting actinium A new medical isotope project shows promise for rapidly producing major quantities of a new cancer-treatment agent, actinium 225 (Ac-225). April 11, 2012 Los Alamos scientist Meiring Nortier holds a thorium foil test target for the proof-of-concept production experiments. Los Alamos scientist Meiring Nortier holds a thorium foil test target for the proof-of-concept production experiments.

  11. Picture of the Week: Hot cells for medical isotopes

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

    2 Hot cells for medical isotopes Isotopes from Los Alamos are used for the diagnosis of cardiac disease, calibration of PET scanners which in turn diagnose cancer, neurological disease, inflammatory diseases, trauma, and other circulatory diseases, and are increasingly being investigated for their potential to treat a variety of localized pathologies. June 7, 2015 Hot cells for medical isotopes x View extra-large image on Flickr » Every year, over 1,000,000 cardiac, cancer and other patients

  12. COLLOQUIUM: Facility for Rare Isotope Beams - Scientific Opportunities and

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

    Technical Challenges | Princeton Plasma Physics Lab February 4, 2015, 4:00pm to 5:30pm Colloquia MBG Auditorium COLLOQUIUM: Facility for Rare Isotope Beams - Scientific Opportunities and Technical Challenges Dr. Georg Bollen Michigan State University - The Facility for Rare Isotope Beams Wednesday Colloquium, February 4, 2015, "Facility for Rare Isotope Beams - Scientific Opportunities and Technial Chanllenges", Dr. Georg Bollen Colloquium Committee: The Princeton Plasma Physics

  13. Oxygen And Carbon Isotope Ratios Of Hydrothermal Minerals From...

    Open Energy Info (EERE)

    Oxygen And Carbon Isotope Ratios Of Hydrothermal Minerals From Yellowstone Drill Cores Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Oxygen...

  14. Isotopic Analysis- Gas At Long Valley Caldera Geothermal Area...

    Open Energy Info (EERE)

    Through 30 September Activity T. Winnett, Cathy J. Janik (1986) Isotopic Composition of Carbon in Fluids from the Long Valley Geothermal System, California, In- Proceedings of...

  15. Isotopic Analysis At Newberry Caldera Area (Goles & Lambert,...

    Open Energy Info (EERE)

    Rock Activity Date Usefulness not indicated DOE-funding Unknown References Gordon G. Goles, Richard St J. Lambert (1990) A Strontium Isotopic Study Of Newberry Volcano,...

  16. Isotopic Analysis At Northern Basin & Range Region (Cole, 1983...

    Open Energy Info (EERE)

    Cole, 1983) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis At Northern Basin & Range Region (Cole, 1983) Exploration Activity...

  17. Isotopic Analysis- Fluid At Salt Wells Area (Shevenell & Garside...

    Open Energy Info (EERE)

    At Salt Wells Area (Shevenell & Garside, 2003) Exploration Activity Details Location Salt Wells Geothermal Area Exploration Technique Isotopic Analysis- Fluid Activity Date 2002 -...

  18. Establishment of the Heavy Isotopes Lead Materials Management...

    Office of Scientific and Technical Information (OSTI)

    Materials Management Organization (LMMO) Citation Details In-Document Search Title: Establishment of the Heavy Isotopes Lead Materials Management Organization (LMMO) Authors: ...

  19. Isotopic Analysis- Fluid At Rose Valley Geothermal Area (1990...

    Open Energy Info (EERE)

    Rose Valley Geothermal Area (1990) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Fluid At Rose Valley Geothermal Area (1990)...

  20. Isotopic Analysis-Fluid At Long Valley Caldera Geothermal Area...

    Open Energy Info (EERE)

    Estimate deep reservoir temperature Notes The oxygen isotope compositions of dissolved sulfate and water from hot springs and shallow drillholes have been tested. Methods are...

  1. Isotopic Analysis-Fluid At Yellowstone Caldera Geothermal Region...

    Open Energy Info (EERE)

    Estimate deep reservoir temperature Notes The oxygen isotope compositions of dissolved sulfate and water from hot springs and shallow drillholes have been tested. Methods are...

  2. Isotopic Analysis At Valles Caldera - Redondo Geothermal Area...

    Open Energy Info (EERE)

    Exploration Activity: Isotopic Analysis At Valles Caldera - Redondo Geothermal Area (Phillips, 2004) Exploration Activity Details Location Valles Caldera - Redondo Geothermal Area...

  3. Isotopic Analysis- Rock At Valles Caldera - Sulphur Springs Geothermal...

    Open Energy Info (EERE)

    Phillips, 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Rock At Valles Caldera - Sulphur Springs Geothermal Area...

  4. Isotopic Analysis At Walker-Lane Transitional Zone Region (Laney...

    Open Energy Info (EERE)

    Zone Region (Laney, 2005) Exploration Activity Details Location Walker-Lane Transition Zone Geothermal Region Exploration Technique Isotopic Analysis- Fluid Activity Date...

  5. Temperature effects on the behavior of liquid hydrogen isotopes...

    Office of Scientific and Technical Information (OSTI)

    liquid hydrogen isotopes inside a spherical-shell directly driven inertial confinement fusion target Kim, K.; Mok, L.S. 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; LASER TARGETS;...

  6. Isotopic Analysis At Yellowstone Region (Sturchio, Et Al., 1990...

    Open Energy Info (EERE)

    Yellowstone Caldera Geothermal Region Exploration Technique Isotopic Analysis- Fluid Activity Date Usefulness could be useful with more improvements DOE-funding Unknown Notes...

  7. Isotopic Analysis- Fluid At Coso Geothermal Area (1982) | Open...

    Open Energy Info (EERE)

    Details Location Coso Geothermal Area Exploration Technique Isotopic Analysis- Fluid Activity Date 1982 Usefulness not indicated DOE-funding Unknown Exploration Basis...

  8. Strontium Isotopes Test Long-Term Zonal Isolation of Injected...

    Office of Scientific and Technical Information (OSTI)

    Water after Hydraulic Fracturing Citation Details In-Document Search Title: Strontium Isotopes Test Long-Term Zonal Isolation of Injected and Marcellus Formation Water after ...

  9. Isotopic Analysis At Long Valley Caldera Geothermal Area (Smith...

    Open Energy Info (EERE)

    Smith & Suemnicht, 1991) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis At Long Valley Caldera Geothermal Area (Smith &...

  10. Atomic weight and isotopic abundance data analysis 1993

    SciTech Connect (OSTI)

    Holden, N.E.

    1993-08-01

    Literature on isotopic abundance measurements and their variation in nature have been reviewed for impact on standard atomic weight values and associated uncertainties for recent measurements.

  11. Isotopic Analysis- Fluid At Roosevelt Hot Springs Geothermal...

    Open Energy Info (EERE)

    Unknown Exploration Basis Faulder 1991 Conceptual Geological Model compilation and literature review of the Roosevelt Hot Springs Geothermal Area. Notes Stable isotope analysis...

  12. Hydrogeological And Isotopic Survey Of Geothermal Fields In The...

    Open Energy Info (EERE)

    Hydrogeological And Isotopic Survey Of Geothermal Fields In The Buyuk Menderes Graben, Turkey Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article:...

  13. John De Laeter Centre For Isotope Research | Open Energy Information

    Open Energy Info (EERE)

    2013 DOI Not Provided Check for DOI availability: http:crossref.org Online Internet link for John De Laeter Centre For Isotope Research Citation Curtin University. John...

  14. Isotopic Analysis At Lassen Volcanic National Park Area (Janik...

    Open Energy Info (EERE)

    Park Area (Janik & Mclaren, 2010) Exploration Activity Details Location Lassen Volcanic National Park Area Exploration Technique Isotopic Analysis- Fluid Activity Date Usefulness...

  15. Method of isotope separation by chemi-ionization

    DOE Patents [OSTI]

    Wexler, Sol; Young, Charles E.

    1977-05-17

    A method for separating specific isotopes present in an isotopic mixture by aerodynamically accelerating a gaseous compound to form a jet of molecules, and passing the jet through a stream of electron donor atoms whereby an electron transfer takes place, thus forming negative ions of the molecules. The molecular ions are then passed through a radiofrequency quadrupole mass filter to separate the specific isotopes. This method may be used for any compounds having a sufficiently high electron affinity to permit negative ion formation, and is especially useful for the separation of plutonium and uranium isotopes.

  16. Integrated Approach to Use Natural Chemical and Isotopic Tracers...

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

    Fracture Spacing and Surface Area in EGS Systems Integrated Approach to Use Natural Chemical and Isotopic Tracers to Estimate Fracture Spacing and Surface Area in EGS Systems DOE ...

  17. Small-Scale Reactor for the Production of Medical Isotopes -...

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

    Small-Scale Reactor for the Production of Medical Isotopes Sandia National Laboratories ... Out LEU reactor is ready to construct -US government is looking for investors. We have ...

  18. Final Report, NEAC Subcommittee for Isotope Research & Production...

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

    has been especially successful in both medical diagnostic and therapeutic arenas, it is ... This report assesses the current status of radioactive and stable isotope availability for ...

  19. High Flux Isotope Reactor | Neutron Science at ORNL

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

    HFIR is also used for medical, industrial, and research isotope production; research on severe neutron damage to materials; and neutron activation analysis to examine trace ...

  20. 2008 Workshop on The Nation's Needs for Isotopes: Present and...

    Office of Science (SC) Website

    ... energy, medical and national security applications and outcomes. During this transition period, the Department will continue production of its current portfolio of isotope products ...

  1. Isotopic Analysis- Gas At Chena Geothermal Area (Kolker, Et Al...

    Open Energy Info (EERE)

    Date 2007 - 2007 Usefulness useful DOE-funding Unknown Exploration Basis Lawrence Berkeley National Laboratory sampling and analysis of He isotopes from Chena Hot Springs....

  2. Isotopic Analysis- Fluid At Long Valley Caldera Geothermal Area...

    Open Energy Info (EERE)

    Long Valley Caldera Geothermal Area (Taylor & Gerlach, 1983) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Fluid At Long...

  3. Isotopic Analysis-Fluid At Raft River Geothermal Area (1982)...

    Open Energy Info (EERE)

    GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis-Fluid At Raft River Geothermal Area (1982) Exploration Activity Details Location Raft River...

  4. Isotopic Analysis-Fluid At Raft River Geothermal Area (1977)...

    Open Energy Info (EERE)

    GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis-Fluid At Raft River Geothermal Area (1977) Exploration Activity Details Location Raft River...

  5. Efficient and selective isotopic labeling of hemes to facilitate...

    Office of Scientific and Technical Information (OSTI)

    This method achieves, in a single step, efficient expression and incorporation of hemes isotopically labeled in specific atom positions adequate for spectroscopic characterization ...

  6. Isotopic Analysis At Long Valley Caldera Geothermal Area (Evans...

    Open Energy Info (EERE)

    search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis At Long Valley Caldera Geothermal Area (Evans, Et Al., 2002) Exploration Activity Details...

  7. Geothermal Reservoir Temperatures Estimated from the Oxygen Isotope...

    Open Energy Info (EERE)

    western United States. Limited analyses of spring and borehole fluids and existing experimental rate studies suggest that dissolved sulfate and water are probably in isotopic...

  8. Isotopic Analysis At San Juan Volcanic Field Area (Larson & Jr...

    Open Energy Info (EERE)

    San Juan Volcanic Field Area (Larson & Jr, 1986) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis At San Juan Volcanic Field...

  9. Isotopic Analysis At Nw Basin & Range Region (Laney, 2005) |...

    Open Energy Info (EERE)

    Location Northwest Basin and Range Geothermal Region Exploration Technique Isotopic Analysis- Fluid Activity Date Usefulness not indicated DOE-funding Unknown Notes...

  10. Isotopic Analysis At Central Nevada Seismic Zone Region (Laney...

    Open Energy Info (EERE)

    Location Central Nevada Seismic Zone Geothermal Region Exploration Technique Isotopic Analysis- Fluid Activity Date Usefulness not indicated DOE-funding Unknown Notes...

  11. Isotopic Analysis- Fluid At Coso Geothermal Area (1990) | Open...

    Open Energy Info (EERE)

    Exploration Activity Details Location Coso Geothermal Area Exploration Technique Isotopic Analysis- Fluid Activity Date 1990 Usefulness not indicated DOE-funding Unknown...

  12. Isotopic Analysis At Clear Lake Area (Thompson, Et Al., 1992...

    Open Energy Info (EERE)

    Exploration Activity Details Location Clear Lake Area Exploration Technique Isotopic Analysis- Fluid Activity Date Usefulness useful DOE-funding Unknown Notes Deuterium and...

  13. Isotopic Analysis- Fluid At Indian Valley Hot Springs Geothermal...

    Open Energy Info (EERE)

    Details Location Indian Valley Hot Springs Geothermal Area Exploration Technique Isotopic Analysis- Fluid Activity Date 1990 Usefulness not indicated DOE-funding Unknown...

  14. Isotopic Analysis- Rock At Valles Caldera - Sulphur Springs Area...

    Open Energy Info (EERE)

    Details Location Valles Caldera - Sulphur Springs Area Exploration Technique Isotopic Analysis- Rock Activity Date Usefulness not indicated DOE-funding Unknown References...

  15. Isotopic Analysis At Northern Basin & Range Region (Laney, 2005...

    Open Energy Info (EERE)

    Location Northern Basin and Range Geothermal Region Exploration Technique Isotopic Analysis- Fluid Activity Date Usefulness not indicated DOE-funding Unknown Notes...

  16. Isotopic Analysis- Fluid At Sierra Valley Geothermal Area (1990...

    Open Energy Info (EERE)

    Activity Details Location Sierra Valley Geothermal Area Exploration Technique Isotopic Analysis- Fluid Activity Date 1990 Usefulness not indicated DOE-funding Unknown...

  17. Isotopic Analysis At Buffalo Valley Hot Springs Area (Laney,...

    Open Energy Info (EERE)

    Activity Details Location Buffalo Valley Hot Springs Area Exploration Technique Isotopic Analysis- Fluid Activity Date Usefulness not indicated DOE-funding Unknown Notes...

  18. Isotopic Analysis At Mt St Helens Area (Shevenell & Goff, 2000...

    Open Energy Info (EERE)

    Home Exploration Activity: Isotopic Analysis At Mt St Helens Area (Shevenell & Goff, 2000) Exploration Activity Details Location Mt St Helens Area Exploration Technique...

  19. Isotopic Analysis At Valles Caldera - Redondo Geothermal Area...

    Open Energy Info (EERE)

    Goff, Et Al., 1982) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis At Valles Caldera - Redondo Geothermal Area (Goff, Et Al.,...

  20. Isotopic Analysis- Rock At Valles Caldera - Sulphur Springs Geothermal...

    Open Energy Info (EERE)

    WoldeGabriel & Goff, 1992) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Rock At Valles Caldera - Sulphur Springs Geothermal...

  1. Isotopic Analysis- Fluid At Valles Caldera - Redondo Area (Rao...

    Open Energy Info (EERE)

    analyzed for their hydrogen and oxygen isotope contents as a part of previous studies (Goff & Grigsby, 1982; Vuataz & Goff, 1986). The present study focuses on the interpretation...

  2. Isotopic Analysis At Yellowstone Region (Goff & Janik, 2002)...

    Open Energy Info (EERE)

    Goff & Janik, 2002) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis At Yellowstone Region (Goff & Janik, 2002) Exploration...

  3. Isotopic Analysis At Jemez Springs Area (Rao, Et Al., 1996) ...

    Open Energy Info (EERE)

    analyzed for their hydrogen and oxygen isotope contents as a part of previous studies (Goff & Grigsby, 1982; Vuataz & Goff, 1986). The present study focuses on the interpretation...

  4. Isotopic Analysis- Fluid At Valles Caldera - Sulphur Springs...

    Open Energy Info (EERE)

    analyzed for their hydrogen and oxygen isotope contents as a part of previous studies (Goff & Grigsby, 1982; Vuataz & Goff, 1986). The present study focuses on the interpretation...

  5. Isotopic Analysis- Fluid At Fenton Hill HDR Geothermal Area ...

    Open Energy Info (EERE)

    analyzed for their hydrogen and oxygen isotope contents as a part of previous studies (Goff & Grigsby, 1982; Vuataz & Goff, 1986). The present study focuses on the interpretation...

  6. Isotopic Analysis At Mt St Helens Area (Shevenell & Goff, 1995...

    Open Energy Info (EERE)

    Home Exploration Activity: Isotopic Analysis At Mt St Helens Area (Shevenell & Goff, 1995) Exploration Activity Details Location Mt St Helens Area Exploration Technique...

  7. Isotopic Analysis- Fluid At Valles Caldera - Sulphur Springs...

    Open Energy Info (EERE)

    Activity: Isotopic Analysis- Fluid At Valles Caldera - Sulphur Springs Geothermal Area (Goff, Et Al., 1982) Exploration Activity Details Location Valles Caldera - Sulphur Springs...

  8. Isotopic Analysis- Fluid At Valles Caldera - Sulphur Springs...

    Open Energy Info (EERE)

    Activity: Isotopic Analysis- Fluid At Valles Caldera - Sulphur Springs Geothermal Area (Goff, Et Al., 1985) Exploration Activity Details Location Valles Caldera - Sulphur Springs...

  9. Isotopic Analysis At Jemez Springs Area (Goff & Janik, 2002)...

    Open Energy Info (EERE)

    Goff & Janik, 2002) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis At Jemez Springs Area (Goff & Janik, 2002) Exploration...

  10. Perspectives on Project Finance | Department of Energy

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

    Perspectives on Project Finance Perspectives on Project Finance Plenary III: Project Finance and Investment Perspectives on Project Finance John May, Managing Partner, Stern Brothers & Co. may_biomass_2014.pdf (476.25 KB) More Documents & Publications Opportunities in Bond Financing Tribal Renewable Energy Advanced Course: Community Scale Project Development Tribal Renewable Energy Advanced Course: Commercial Scale Project Development

  11. Single and double resonance spectroscopy of methanol embedded in superfluid helium nanodroplets

    SciTech Connect (OSTI)

    Raston, Paul L.; Douberly, Gary E.; Jger, Wolfgang

    2014-07-28

    Methanol is one of the simplest molecules that undergo torsional oscillations, and so it has been extensively studied in the gas phase by various spectroscopic techniques. At 300 K, a large number of rotational, torsional, and vibrational energy levels is populated, and this makes for a rather complicated spectrum, which is still not fully understood. It is expected that in going from 300 K to 0.4 K (the temperature of helium nanodroplets) the population distribution of methanol will mainly collapse into two states; the J{sub K} = 0{sub 0} state for the A{sub 1} nuclear spin symmetry species (with I{sub CH{sub 3}} = 3/2), and the J{sub K} = 1{sub ?1} state for the E species (I{sub CH{sub 3}} = 1/2). This results in a simplified spectrum that consists of narrow a-type (?K = 0) lines and broader b- and c-type (?K = 1) lines. We have recorded the rotovibrational spectrum of CH{sub 3}OH in the OH stretching, CH{sub 3} stretching and bending, CH{sub 3} rocking, and CO stretching regions, and have firmly assigned five bands (v{sub 1}, v{sub 2}, v{sub 3}, v{sub 7}, and v{sub 8}), and tentatively assigned five others (v{sub 9}, 2v{sub 4}, v{sub 4} + v{sub 10}, 2v{sub 10}, and v{sub 4} + v{sub 5}). To our knowledge, the transitions we have assigned within the v{sub 4} + v{sub 10}, 2v{sub 10}, and v{sub 4} + v{sub 5} bands have not yet been assigned in the gas phase, and we hope that considering the very small matrix shift in helium nanodroplets (<1 cm{sup ?1} for most subband origins of CH{sub 3}OH), those made here can aid in their gas phase identification. Microwave-infrared double resonance spectroscopy was used to confirm the initially tentative a-type infrared assignments in the OH stretching (v{sub 1}) band of A{sub 1} species methanol, in addition to revealing warm b-type lines. From a rotovibrational analysis, the B rotational constant is found to be reduced quite significantly (56%) with respect to the gas phase, and the torsional tunneling splittings are

  12. Sensitivity of helium beam-modulator design to uncertainties in biological data

    SciTech Connect (OSTI)

    Petti, P.L.; Lyman, J.T.; Castro, J.R. )

    1991-05-01

    The goal in designing beam-modulating devices for heavy charged-particle therapy is to achieve uniform biological effects across the spread-peak region of the beam. To accomplish this, the linear-quadratic model for cell survival has been used to describe the biological response of the target cells to charged-particle radiation. In this paper, the sensitivity of the beam-modulator design in the high-dose region to the values of the linear-quadratic variables {alpha} and {beta} has been investigated for a 215-MeV/u helium beam, and implications for higher LET beams are discussed. The major conclusions of this work are that, for helium over the LET range of 2 to 16 keV/{mu}, uncertainties in measuring {alpha} and {beta} for a given cell type which are of the order 20% or less have a negligible effect on the beam-modulator design (i.e., on the slope of the spread Bragg peak); uncertainties less than or equal to 10% in the dose-averaged LET at each depth are unimportant; and, if the linear-quadratic variables for the tumor differ from those used in the beam-modulator design by a constant factor between about 0.5 and 3, then the resultant nonuniformity in the photon-equivalent dose delivered to the tumor is within {plus minus}2.5%. It is also shown that for any ion, if the nominal values of {alpha} or {beta} used by the beam-modulator design program differ from their actual values by a constant factor, then the maximum errors possible in the beam-modulator design may be characterized by two limiting depth-dose curves such that the ratio of the dose at the proximal end of the spread Bragg curve to the dose at the distal end of the spread peak is given by {alpha}{sub distal}/{alpha}{sub prox} for the steepest curve, and ({beta}{sub distal}/{beta}{sub prox}){sup 1/2} for the flattest curve.

  13. Apparatus for isotopic alteration of mercury vapor

    DOE Patents [OSTI]

    Grossman, Mark W.; George, William A.; Marcucci, Rudolph V.

    1988-01-01

    An apparatus for enriching the isotopic Hg content of mercury is provided. The apparatus includes a reactor, a low pressure electric discharge lamp containing a fill including mercury and an inert gas. A filter is arranged concentrically around the lamp. In a preferred embodiment, constant mercury pressure is maintained in the filter by means of a water-cooled tube that depends from it, the tube having a drop of mercury disposed in it. The reactor is arranged around the filter, whereby radiation from said lamp passes through the filter and into said reactor. The lamp, the filter and the reactor are formed of a material which is transparent to ultraviolet light.

  14. Measurement of Plutonium Isotopic Composition - MGA

    SciTech Connect (OSTI)

    Vo, Duc Ta

    2015-08-21

    In this module, we will use the Canberra InSpector-2000 Multichannel Analyzer with a high-purity germanium detector (HPGe) and the MGA isotopic anlysis software to assay a variety of plutonium samples. The module provides an understanding of the MGA method, its attributes and limitations. You will assess the system performance by measuring a range of materials similar to those you may assay in your work. During the final verification exercise, the results from MGA will be combined with the 240Pueff results from neutron coincidence or multiplicity counters so that measurements of the plutonium mass can be compared with the operator-declared (certified) values.

  15. Laser-assisted isotope separation of tritium

    DOE Patents [OSTI]

    Herman, Irving P. (Castro Valley, CA); Marling, Jack B. (Livermore, CA)

    1983-01-01

    Methods for laser-assisted isotope separation of tritium, using infrared multiple photon dissociation of tritium-bearing products in the gas phase. One such process involves the steps of (1) catalytic exchange of a deuterium-bearing molecule XYD with tritiated water DTO from sources such as a heavy water fission reactor, to produce the tritium-bearing working molecules XYT and (2) photoselective dissociation of XYT to form a tritium-rich product. By an analogous procedure, tritium is separated from tritium-bearing materials that contain predominately hydrogen such as a light water coolant from fission or fusion reactors.

  16. CONTROL SYSTEM FOR ISOTOPE SEPARATING APPARATUS

    DOE Patents [OSTI]

    Barnes, S.W.

    1960-01-26

    A method is described for controlling the position of the ion beams in a calutron used for isotope separation. The U/sup 238/ beams is centered over the U/sup 235/ receiving pocket, the operator monitoring the beam until a maximum reading is achieved on the meter connected to that pocket. Then both beams are simultaneously shifted by a preselected amount to move the U/sup 235/ beam over the U/sup 235/ pocket. A slotted door is placed over the entrance to that pocket during the U/sup 238/ beam centering to reduce the contamination to the pocket, while allowing enough beam to pass for monitoring purposes.

  17. The design, fabrication, operation and maintenance of (41) 400 H. P. -600 SCFM helium screw compressor systems (Five-year operation report)

    SciTech Connect (OSTI)

    Pallaver, C.

    1988-12-01

    Fermi National Accelerator Laboratory (Fermilab) uses thirty-four (34) identical compressor systems connected to a common header to supply clean high pressure helium gas feeding 26 refrigerators supplying liquid helium to 777 super conducting magnets. There are seven (7) similar compressor packages in other locations. The purpose of this paper is (after five years of operation) to present all the problems, modifications and experiences associated with the design and operation of these compressor systems.

  18. Initial assessment of environmental effects on SiC/SiC composites in helium-cooled nuclear systems

    SciTech Connect (OSTI)

    Contescu, Cristian I

    2013-09-01

    This report summarized the information available in the literature on the chemical reactivity of SiC/SiC composites and of their components in contact with the helium coolant used in HTGR, VHTR and GFR designs. In normal operation conditions, ultra-high purity helium will have chemically controlled impurities (water, oxygen, carbon dioxide, carbon monoxide, methane, hydrogen) that will create a slightly oxidizing gas environment. Little is known from direct experiments on the reactivity of third generation (nuclear grade) SiC/SiC composites in contact with low concentrations of water or oxygen in inert gas, at high temperature. However, there is ample information about the oxidation in dry and moist air of SiC/SiC composites at high temperatures. This information is reviewed first in the next chapters. The emphasis is places on the improvement in material oxidation, thermal, and mechanical properties during three stages of development of SiC fibers and at least two stages of development of the fiber/matrix interphase. The chemical stability of SiC/SiC composites in contact with oxygen or steam at temperatures that may develop in off-normal reactor conditions supports the conclusion that most advanced composites (also known as nuclear grade SiC/SiC composites) have the chemical resistance that would allow them maintain mechanical properties at temperatures up to 1200 1300 oC in the extreme conditions of an air or water ingress accident scenario. Further research is needed to assess the long-term stability of advanced SiC/SiC composites in inert gas (helium) in presence of very low concentrations (traces) of water and oxygen at the temperatures of normal operation of helium-cooled reactors. Another aspect that needs to be investigated is the effect of fast neutron irradiation on the oxidation stability of advanced SiC/SiC composites in normal operation conditions.

  19. EVOLUTION OF POST-IMPACT REMNANT HELIUM STARS IN TYPE Ia SUPERNOVA REMNANTS WITHIN THE SINGLE-DEGENERATE SCENARIO

    SciTech Connect (OSTI)

    Pan, Kuo-Chuan; Ricker, Paul M.; Taam, Ronald E. E-mail: pmricker@illinois.edu

    2013-08-10

    The progenitor systems of Type Ia supernovae (SNe Ia) are still under debate. Based on recent hydrodynamics simulations, non-degenerate companions in the single-degenerate scenario (SDS) should survive the supernova (SN) impact. One way to distinguish between the SDS and the double-degenerate scenario is to search for the post-impact remnant stars (PIRSs) in SN Ia remnants. Using a technique that combines multi-dimensional hydrodynamics simulations with one-dimensional stellar evolution simulations, we have examined the post-impact evolution of helium-rich binary companions in the SDS. It is found that these helium-rich PIRSs (He PIRSs) dramatically expand and evolve to a luminous phase (L {approx} 10{sup 4} L{sub Sun }) about 10 yr after an SN explosion. Subsequently, they contract and evolve to become hot blue-subdwarf-like (sdO-like) stars by releasing gravitational energy, persisting as sdO-like stars for several million years before evolving to the helium red-giant phase. We therefore predict that a luminous OB-like star should be detectable within {approx}30 yr after the SN explosion. Thereafter, it will shrink and become an sdO-like star in the central regions of SN Ia remnants within star-forming regions for SN Ia progenitors evolved via the helium-star channel in the SDS. These He PIRSs are predicted to be rapidly rotating (v{sub rot} {approx}> 50 km s{sup -1}) and to have high spatial velocities (v{sub linear} {approx}> 500 km s{sup -1}). Furthermore, if SN remnants have diffused away and are not recognizable at a later stage, He PIRSs could be an additional source of single sdO stars and/or hypervelocity stars.

  20. First principles assessment of helium trapping in Y{sub 2}TiO{sub 5} in nano-featured ferritic alloys

    SciTech Connect (OSTI)

    Jin, Yanan; Jiang, Yong E-mail: odette@engineering.ucsb.edu; Yang, Litong; Lan, Guoqiang; Robert Odette, G. E-mail: odette@engineering.ucsb.edu; Yamamoto, Takuya; Shang, Jiacheng; Dang, Ying

    2014-10-14

    Nano-scale Y{sub 2}Ti{sub 2}O{sub 7} and Y{sub 2}TiO{sub 5} oxides are the major features that provide high strength and irradiation tolerance in nano-structured ferritic alloys. Here, we employ density functional theory to study helium trapping in Y{sub 2}TiO{sub 5}. The results suggest that helium is more deeply trapped in Y{sub 2}TiO{sub 5} compared to Y{sub 2}Ti{sub 2}O{sub 7}. Helium occupies open channels in Y{sub 2}TiO{sub 5}, where it weakly chemically interacts with neighboring oxygen anions, and results in less volume expansion compared to Y{sub 2}Ti{sub 2}O{sub 7}, reducing strains in the iron matrix. The corresponding helium mobility in these channels is very high. While its ultimate fate is to form oxide/matrix interface bubbles, transient deep trapping of helium in oxides plays a major role in the ability of NFA to manage helium distribution.