Sample records for uranium dioxide uranium

  1. Production of uranium dioxide

    Microsoft Academic Search

    J. E. Hart; D. L. Shuck; W. L. Lyon

    1977-01-01

    A continuous, four stage fluidized bed process for converting uranium hexafluoride (UFâ) to ceramic-grade uranium dioxide (UOâ) powder suitable for use in the manufacture of fuel pellets for nuclear reactors is disclosed. The process comprises the steps of first reacting UFâ with steam in a first fluidized bed, preferably at about 550°C, to form solid intermediate reaction products UOâFâ, UâOâ

  2. URANIUM DIOXIDE FABRICATION

    Microsoft Academic Search

    D. W. Brite; R. J. Anicetti

    1960-01-01

    The techniques developed for fabricating (UOâ fuel element cores ; and swageable powders at HAPO are described. A simplified flow chart of some of ; the processes is presented. Types of fuel cores fabricated since the program ; began in 1956 are indicated. The experiences and observations are related both ; in fabricating the uranium dioxide fuel element cores for

  3. Thermodynamic properties of uranium dioxide

    NASA Astrophysics Data System (ADS)

    Fink, J. K.; Chasanov, M. G.; Leibowitz, L.

    1981-04-01

    In order to provide reliable and consistent data on the thermophysical properties of reactor materials for rector safety studies, revision was prepared for the thermodynamic properties of the uranium dioxide portion of the fuel property section of the report Properties for Liquid Metal Fast Breeder Reactors Safety Analysis. International agreement was reached on a vapor pressure equation for the total pressure over UO2, for the calculation of enthalpy and heat capacity, and a phase change at 2670 K. An electronic term is used in place of the Frenkel defect term in the enthalpy and heat capacity equation and the phase transition is accepted.

  4. Dry process fluorination of uranium dioxide using ammonium bifluoride

    E-print Network

    Yeamans, Charles Burnett, 1978-

    2003-01-01

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

  5. Conversion of Uranium Oxide into Nitrate with Nitrogen Dioxide

    Microsoft Academic Search

    Kayo Sawada; Daisuke Hirabayashi; Youichi Enokida; Ichiro Yamamoto

    2008-01-01

    In order to decrease the amount of aqueous liquid waste discharged from nuclear fuel reprocessing, the conversion of uranium dioxide into its nitrate using liquefied nitrogen dioxide was studied. Uranium dioxide powder was immersed in liquefied nitrogen dioxide at 313 K after a pretreatment by the oxidation of the uranium dioxide with nitrogen dioxide and air at 523 K. Seventy-nine

  6. Anisotropic thermal conductivity in uranium dioxide.

    PubMed

    Gofryk, K; Du, S; Stanek, C R; Lashley, J C; Liu, X-Y; Schulze, R K; Smith, J L; Safarik, D J; Byler, D D; McClellan, K J; Uberuaga, B P; Scott, B L; Andersson, D A

    2014-01-01

    The thermal conductivity of uranium dioxide has been studied for over half a century, as uranium dioxide is the fuel used in a majority of operating nuclear reactors and thermal conductivity controls the conversion of heat produced by fission events to electricity. Because uranium dioxide is a cubic compound and thermal conductivity is a second-rank tensor, it has always been assumed to be isotropic. We report thermal conductivity measurements on oriented uranium dioxide single crystals that show anisotropy from 4?K to above 300?K. Our results indicate that phonon-spin scattering is important for understanding the general thermal conductivity behaviour, and also explains the anisotropy by coupling to the applied temperature gradient and breaking cubic symmetry. PMID:25080878

  7. The growth of fission gas bubbles in irradiated uranium dioxide

    Microsoft Academic Search

    R. M. Cornell

    1969-01-01

    The growth of fission gas bubbles from supersaturated solution in irradiated uranium dioxide has been studied by electron microscopy under isothermal annealing conditions between 1300° and 1500°C. Measurements of the kinetics of bubble growth have enabled the diffusion coefficients of atomic xenon and krypton in irradiated uranium dioxide to be determined. The diffusion coefficients obtained may be expressed by the

  8. THERMAL EXPANSION OF URANIUM DIOXIDE. Final Report

    Microsoft Academic Search

    F. A. Halden; H. C. Wohlers; R. H. Reinhart

    1959-01-01

    The thermal expansions of commercial uranium dioxide specimens were ;\\u000a measured up to the melting point. The linear expansion of dense, normal grain ;\\u000a size UOâ follows closely the equationi L = Lâ(1 + 6.0 x 10⁻⁶t + ;\\u000a 2.0 x 10⁻⁹t\\/sup 1.7 x 10⁻¹²t³). An anomalous expansion was ;\\u000a noted in the temperature range 1000 to 1500 deg C.

  9. Exposure to subcutaneously implanted uranium dioxide impairs bone formation.

    PubMed

    Díaz Sylvester, Paula L; López, Ricardo; Ubios, Angela M; Cabrini, Rómulo L

    2002-01-01

    The introduction of uranium particles into subcutaneous tissue is a risk that affects workers engaged in the extraction, purification, and manufacture of uranium, as well as soldiers who are wounded with uranium shrapnel. The authors evaluated the effect of an internal source of an insoluble form of uranium on bone. Uranium dioxide powder (0.125 gm/kg body weight) was implanted subcutaneously in rats. After 30 days, animals exposed to uranium weighed less than controls. Bone formation activity in endochondral ossification and bone growth were also lower in the experimental animals, as evidenced by histomorphometric and morphometric methods. This is the first study to report bone damage resulting from continuous, nonlethal exposure to an insoluble compound of uranium dioxide over a period of 30 days. PMID:12530598

  10. Molten uranium dioxide structure and dynamics

    SciTech Connect

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

    2014-11-20

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

  11. Helium Migration Mechanisms in Polycrystalline Uranium Dioxide

    SciTech Connect

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

    2007-07-01

    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)

  12. Molten uranium dioxide structure and dynamics

    DOE PAGESBeta

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

    2014-11-20

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

  13. Molten uranium dioxide structure and dynamics.

    PubMed

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

    2014-11-21

    Uranium dioxide (UO2) is the major nuclear fuel component of fission power reactors. A key concern during severe accidents is the melting and leakage of radioactive UO2 as it corrodes through its zirconium cladding and steel containment. Yet, the very high temperatures (>3140 kelvin) and chemical reactivity of molten UO2 have prevented structural studies. In this work, we combine laser heating, sample levitation, and synchrotron x-rays to obtain pair distribution function measurements of hot solid and molten UO2. The hot solid shows a substantial increase in oxygen disorder around the lambda transition (2670 K) but negligible U-O coordination change. On melting, the average U-O coordination drops from 8 to 6.7 ± 0.5. Molecular dynamics models refined to this structure predict higher U-U mobility than 8-coordinated melts. PMID:25414311

  14. Molten uranium dioxide structure and dynamics

    DOE PAGESBeta

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

    2014-11-20

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

  15. Configurational analysis of uranium-doped thorium dioxide

    NASA Astrophysics Data System (ADS)

    Shields, A. E.; Ruiz-Hernandez, S. E.; de Leeuw, N. H.

    2015-04-01

    While thorium dioxide is already used industrially in high temperature applications, more insight is needed about the behaviour of the material as part of a mixed-oxide (MOX) nuclear fuel, incorporating uranium. We have developed a new interatomic potential model, commensurate with a prominent existing UO2 potential, to conduct configurational analyses of uranium-doped ThO2 supercells. Using the GULP and Site Occupancy Disorder (SOD) computational codes, we have analysed the distribution of low concentrations of uranium in the bulk material, but have not observed the formation of uranium clusters or a single dominant configuration.

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

    SciTech Connect

    MARUSICH, R.M.

    1998-10-21

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

  17. OXIDATION OF URANIUM ALLOYS IN CARBON DIOXIDE AND AIR

    Microsoft Academic Search

    J. E. Antill; K. A. Peakall

    1961-01-01

    Weight gain--time curves were obtained for alloys of uranium containing ; up to 7.3% silicon, 10% titanium, 5% vanadium, 10% zirconium, 15% molybdenum, 10% ; niobium, and 1% copper in carbon dioxide at 500--1000 deg C and in air at 500 deg ; C. Additions of titanium, molybdenum, niobium, and copper reduced the attack by ; carbon dioxide at 680--1000

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

    DOEpatents

    Stinton, David P. (Knoxville, TN)

    1983-01-01

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

  19. Modeling resistive heating of powdered uranium dioxide. [Fuel vaporization

    Microsoft Academic Search

    R. M. Train; S. Ishikawa; R. J. Keeth; M. P. Manning

    1974-01-01

    Equations for heat transfer with simultaneous electric power dissipation through five concentric cylindrical annuli were formulated for temperature variation in the radial direction only. The equations were developed to simulate an experimental apparatus for vaporization of powdered uranium dioxide in the center annulus. The effect of varying the power inputs, containment sleeve material, void fraction in the powder, and external

  20. Diffusion model of the non-stoichiometric uranium dioxide

    SciTech Connect

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

    2013-07-15

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

  1. X-ray powder diffraction study of the high pressure behaviour of uranium dioxide

    E-print Network

    Paris-Sud XI, Université de

    L-171 X-ray powder diffraction study of the high pressure behaviour of uranium dioxide U. Benedict du bioxyde d'uranium sous des pressions jusqu'à 40 GPa a été étudié par diffraction X sur poudre dans à une délocalisation d'électrons 5f. Abstract. 2014 Uranium dioxide was studied by X-ray powder

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

    E-print Network

    American Society for Testing and Materials. Philadelphia

    2001-01-01

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

  3. Diffusion Coefficient of Fission Gas in Uranium Dioxide Powder Formed by Carbon Dioxide Oxidation of Uranium

    Microsoft Academic Search

    Kiyoaki TAKETANI; Katsuichi IKAWA

    1965-01-01

    In connection with a program to study the behavior of punctured fuel elements for the Tokai Atomic Power Reactor, the diffusion coefficient of fission gas in uranium oxide powder formed by CO2 oxidation of U was determined by post-irradiation experiment, in which the fractional release of fission gas during isothermal heating of the powder was measured. The U was oxidized

  4. Alternative Anodes for the Electrolytic Reduction of Uranium Dioxide

    NASA Astrophysics Data System (ADS)

    Merwin, Augustus

    Reprocessing of spent nuclear fuel is an essential step in closing the nuclear fuel cycle. In order to consume current stockpiles, ceramic uranium dioxide spent nuclear fuel will be subjected to an electrolytic reduction process. The current reduction process employs a platinum anode and a stainless steel alloy 316 cathode in a molten salt bath consisting of LiCl-2wt% Li 2O and occurs at 700°C. A major shortcoming of the existing process is the degradation of the platinum anode under the severely oxidizing conditions encountered during electrolytic reduction. This work investigates alternative anode materials for the electrolytic reduction of uranium oxide. The high temperature and extreme oxidizing conditions encountered in these studies necessitated a unique set of design constraints on the system. Thus, a customized experimental apparatus was designed and constructed. The electrochemical experiments were performed in an electrochemical reactor placed inside a furnace. This entire setup was housed inside a glove box, in order to maintain an inert atmosphere. This study investigates alternative anode materials through accelerated corrosion testing. Surface morphology was studied using scanning electron microscopy. Surface chemistry was characterized using energy dispersive spectroscopy and Raman spectroscopy. Electrochemical behavior of candidate materials was evaluated using potentiodynamic polarization characteristics. After narrowing the number of candidate electrode materials, ferrous stainless steel alloy 316, nickel based Inconel 718 and elemental tungsten were chosen for further investigation. Of these materials only tungsten was found to be sufficiently stable at the anodic potential required for electrolysis of uranium dioxide in molten salt. The tungsten anode and stainless steel alloy 316 cathode electrode system was studied at the required reduction potential for UO2 with varying lithium oxide concentrations. Electrochemical impedance spectroscopy showed mixed (kinetic and diffusion) control and an overall low impedance due to extreme corrosion. It was observed that tungsten is sufficiently stable in LiCl - 2wt% Li 2O at 700°C at the required anodic potential for the reduction of uranium oxide. This study identifies tungsten to be a superior anode material to platinum for the electrolytic reduction of uranium oxide, both in terms of superior corrosion behavior and reduced cost, and thus recommends that tungsten be further investigated as an alternative anode for the electrolytic reduction of uranium dioxide.

  5. Dissolution of sludges containing uranium dioxide and metallic uranium in nitric acid

    SciTech Connect

    Flament, T.A.

    1998-08-25

    The dissolution in nitric acid of sludges containing uranium oxide and uranium has been modeled. That study has shown that it was necessary to continuously feed the dissolver to have an appropriate control of the reaction. If a unique procedure is deemed preferable, NH03 6M has been used.

  6. Molecular Dynamics Simulation of Thermodynamic Properties in Uranium Dioxide

    SciTech Connect

    Wang, Xiangyu; Wu, Bin; Gao, Fei; Li, Xin; Sun, Xin; Khaleel, Mohammad A.; Akinlalu, Ademola V.; Liu, L.

    2014-03-01

    In the present study, we investigated the thermodynamic properties of uranium dioxide (UO2) by molecular dynamics (MD) simulations. As for solid UO2, the lattice parameter, density, and enthalpy obtained by MD simulations were in good agreement with existing experimental data and previous theoretical predictions. The calculated thermal conductivities matched the experiment results at the midtemperature range but were underestimated at very low and very high temperatures. The calculation results of mean square displacement represented the stability of uranium at all temperatures and the high mobility of oxygen toward 3000 K. By fitting the diffusivity constant of oxygen with the Vogel-Fulcher-Tamman law, we noticed a secondary phase transition near 2006.4 K, which can be identified as a ‘‘strong’’ to ‘‘fragile’’ supercooled liquid or glass phase transition in UO2. By fitting the oxygen diffusion constant with the Arrhenius equation, activation energies of 2.0 and 2.7 eV that we obtained were fairly close to the recommended values of 2.3 to 2.6 eV. Xiangyu Wang, Bin Wu, Fei Gao, Xin Li, Xin Sun, Mohammed A. Khaleel, Ademola V. Akinlalu and Li Liu

  7. Strain fields and line energies of dislocations in uranium dioxide.

    PubMed

    Parfitt, David C; Bishop, Clare L; Wenman, Mark R; Grimes, Robin W

    2010-05-01

    Computer simulations are used to investigate the stability of typical dislocations in uranium dioxide. We explain in detail the methods used to produce the dislocation configurations and calculate the line energy and Peierls barrier for pure edge and screw dislocations with the shortest Burgers vector ½?110?. The easiest slip system is found to be the {100}?110? system for stoichiometric UO(2), in agreement with experimental observations. We also examine the different strain fields associated with these line defects and the close agreement between the strain field predicted by atomic scale models and the application of elastic theory. Molecular dynamics simulations are used to investigate the processes of slip that may occur for the three different edge dislocation geometries and nudged elastic band calculations are used to establish a value for the Peierls barrier, showing the possible utility of the method in investigating both thermodynamic average behaviour and dynamic processes such as creep and plastic deformation. PMID:21393662

  8. High temperature behavior of metallic inclusions in uranium dioxide

    SciTech Connect

    Yang, R.L.

    1980-08-01

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

  9. Raman spectroscopic investigation of thorium dioxide-uranium dioxide (ThO?-UO?) fuel materials.

    PubMed

    Rao, Rekha; Bhagat, R K; Salke, Nilesh P; Kumar, Arun

    2014-01-01

    Raman spectroscopic investigations were carried out on proposed nuclear fuel thorium dioxide-uranium dioxide (ThO2-UO2) solid solutions and simulated fuels based on ThO2-UO2. Raman spectra of ThO2-UO2 solid solutions exhibited two-mode behavior in the entire composition range. Variations in mode frequencies and relative intensities of Raman modes enabled estimation of composition, defects, and oxygen stoichiometry in these compounds that are essential for their application. The present study shows that Raman spectroscopy is a simple, promising analytical tool for nondestructive characterization of this important class of nuclear fuel materials. PMID:24405953

  10. Uranium Ore Uranium is extracted

    E-print Network

    Milling of Uranium Ore Uranium is extracted from ore with strong acids or bases. The uranium is concentrated in a solid substance called"yellowcake." Chemical Conversion Plants convert the uranium in yellowcake to uranium hexafluoride (UF6 ), a compound that can be made into nuclear fuel. Enrichment

  11. Surface properties of uranium dioxide from first principles

    NASA Astrophysics Data System (ADS)

    Hoover, Megan E.; Atta-Fynn, Raymond; Ray, Asok K.

    2014-09-01

    Computational modeling of the properties of clean uranium dioxide (UO2) surfaces is a necessary step to modeling and understanding UO2 surface mechanisms such as corrosion and the formation of complex species via environmental gas adsorption. In this work, all-electron hybrid density functional theory, including spin-orbit coupling effects, has been used to study the evolution of the work function, surface energy, incremental energy, and band gap of the clean (1 1 0) and (1 1 1) surfaces of UO2 with respect to the system size. At five layers of formula units and beyond the surface properties of UO2 converge. The estimated work function, surface energy, and band gap of the (1 1 1) surface were 3.5 eV, 0.97 J/m2, and 1.2 eV respectively; the corresponding values for the (1 1 0) surface were 2.2 eV, 1.76 J/m2, and 0.65 eV respectively. The localization of the 5f electron states is pronounced at the top surface layer while bulk-like behavior is exhibited at and below the subsurface layer. The Mott-Hubbard type insulating behavior in the bulk is retained in the surfaces, albeit with a smaller band gap.

  12. Impact of homogeneous strain on uranium vacancy diffusion in uranium dioxide

    NASA Astrophysics Data System (ADS)

    Goyal, Anuj; Phillpot, Simon R.; Subramanian, Gopinath; Andersson, David A.; Stanek, Chris R.; Uberuaga, Blas P.

    2015-03-01

    We present a detailed mechanism of, and the effect of homogeneous strains on, the migration of uranium vacancies in UO2. Vacancy migration pathways and barriers are identified using density functional theory and the effect of uniform strain fields are accounted for using the dipole tensor approach. We report complex migration pathways and noncubic symmetry associated with the uranium vacancy in UO2 and show that these complexities need to be carefully accounted for to predict the correct diffusion behavior of uranium vacancies. We show that under homogeneous strain fields, only the dipole tensor of the saddle with respect to the minimum is required to correctly predict the change in the energy barrier between the strained and the unstrained case. Diffusivities are computed using kinetic Monte Carlo simulations for both neutral and fully charged state of uranium single and divacancies. We calculate the effect of strain on migration barriers in the temperature range 800-1800 K for both vacancy types. Homogeneous strains as small as 2 % have a considerable effect on diffusivity of both single and divacancies of uranium, with the effect of strain being more pronounced for single vacancies than divacancies. In contrast, the response of a given defect to strain is less sensitive to changes in the charge state of the defect. Further, strain leads to anisotropies in the mobility of the vacancy and the degree of anisotropy is very sensitive to the nature of the applied strain field for strain of equal magnitude. Our results suggest that the influence of strain on vacancy diffusivity will be significantly greater when single vacancies dominate the defect structure, such as sintering, while the effects will be much less substantial under irradiation conditions where divacancies dominate.

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

    SciTech Connect

    Nelson, Andrew T. [Los Alamos National Laboratory

    2012-08-30

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

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

    E-print Network

    Igor Iosilevskiy; Victor Gryaznov

    2010-05-23

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

  15. Penetrate-leach dissolution of zirconium-clad uranium and uranium dioxide fuels

    Microsoft Academic Search

    1975-01-01

    A new decladding-dissolution process was developed for zirconium-clad uranium metal and UO fuels. The proposed penetrate-leach process consists of penetrating the zirconium cladding with Alniflex solution (2M HF--1M HNO--1M Al(NO)--0.1M KCrO) and of leaching the exposed core with 10M HNO. Undissolved cladding pieces are discarded as solid waste. Periodic HF and HNO additions, efficient agitation, and in-line zirconium analyses are

  16. Determination of oxygen to uranium ratio in irradiated uranium dioxide by controlled potential coulometry

    Microsoft Academic Search

    S. R. Sarkar; K. Une; Y. Tominaga

    1997-01-01

    This work reports the determination of oxygen to uranium (O\\/U) ratio in irradiated UO2+x\\u000a fuel pellet of burnup of ca. 34 GWd\\/t by controlled potential coulometry. The method is based on the dissolution of the nuclear fuel in strong phosphoric acid (SPA) at 180–190 °C under an inert atmosphere. After dissolution, 8% sulphuric acid is added in order to obtain

  17. Simulation of uranium dioxide polymorphs and their phase transitions

    NASA Astrophysics Data System (ADS)

    Fossati, Paul C. M.; Van Brutzel, Laurent; Chartier, Alain; Crocombette, Jean-Paul

    2013-12-01

    In this article first-principles DFT calculations and molecular dynamics simulations using empirical potentials have been used to study four different polymorphs of uranium dioxide that appear under high compressive and tensile deformations. It has been found, as expected, that the ground-state structure is the fluorite-type structure (space group Fm3¯m). Under high compressive deformation urania transforms into cotunnite-type structure (space group Pnma), as already known experimentally. The calculated transition pressure is 28 GPa in agreement with the experimental data. Under tensile deformation urania transforms into either scrutinyite-type structure (space group Pbcn) or rutile-type (space group P42/mnm) structure. These two phases are almost energetically degenerate; hence it is impossible to distinguish which phase is the most favorable. The transition pressure for both phases is found to be equal to -10 GPa. Subsequently, assessment of four of the most used empirical potentials for UO2—Morelon, Arima, Basak, and Yakub—have been carried out comparing the equations of state with those found with DFT calculations. The Morelon potential has been found to be the most accurate to describe the different urania polymorphs. Using this empirical potential and a dedicated minimization procedure, complete transition pathways between the ground state (Fm3¯m) and both tensile structures (Pbcn or P42/mnm) are described. Finally, uniaxial tensile load molecular dynamics simulations have been performed. It has been found that for load in the <100> direction urania transforms into the Pbcn structure while for load in the <110> direction it transits towards the P42/mnm structure.

  18. 332 Journal of The Anterican Ceranaic Society -Aksay et al. Vol. 62, NO.7-8 "H.Marchandise. "Thermal Conductivity of Uranium Dioxide." Commission of

    E-print Network

    Aksay, Ilhan A.

    .Marchandise. "Thermal Conductivity of Uranium Dioxide." Commission of loA. B.G. Washington, "Preferred Values forthe Kernenergetik der Universitaet Stuttgart Rept. No. IRS- "Thermodvnamic and Transwrt Prooenies of Uranium Dioxide Conducthy of UraniumDioxide on Density, Microstructure, Stoichiometry, and Thermal-Neutron Irradiation

  19. DEPLETED URANIUM DIOXIDE-STEEL CERMETS FOR SPENT-NUCLEAR-FUEL MULTIPURPOSE CASKS

    Microsoft Academic Search

    Charles W. Forsberg; M. Jonathan Haire

    An alternative spent nuclear fuel (SNF) management system is proposed for the U.S. Department of Energy and utility SNF that uses multipurpose casks made of a depleted uranium dioxide (DUO2)-steel cermet. The proposed Yucca Mountain repository is designed for SNF received in transport casks. The SNF assemblies or SNF in baskets are transferred to repository waste packages that, in turn,

  20. Spin-phonon interactions to control the thermal transport in uranium dioxide

    NASA Astrophysics Data System (ADS)

    Gofryk, K.; Du, S.; Stanek, C. R.; Lashley, J. C.; Liu, X.-Y.; Schulze, R. K.; Smith, J. L.; Safarik, D. J.; Byler, D. D.; McClellan, K. J.; Uberuaga, B. P.; Scott, B. L.; Andersson, D. A.

    2015-03-01

    Despite more than sixty years of intense research of uranium dioxide, a thorough understanding is lacking for the microscopic processes that control its transport and thermodynamic properties. In particular, it is not clear how different degrees of freedom and quasiparticle excitations interact and what is the relationship to the thermal behavior. We report our new experimental and theoretical studies on oriented and well characterized single crystals of uranium dioxide. Our results indicate that strong spin-phonon coupling and resonant scattering are important for understanding the general thermal behavior, and also explains the observed anisotropy in thermal conductivity by coupling to the applied temperature gradient and breaking cubic symmetry. We will discuss implications of these results.

  1. AN INTEGRATED ONCE-THROUGH FUEL CYCLE WITH DEPLETED-URANIUM-DIOXIDE SNF MULTIFUNCTION CASKS

    Microsoft Academic Search

    Charles W. Forsberg; Les R. Dole

    An advanced once-through nuclear fuel cycle is proposed that integrates (1) front- and back-end fuel cycle operations and (2) management of all long-lived radionuclides. The front-end of the fuel cycle remains unchanged except that the depleted uranium (DU) from the enrichment facilities (in the form of DU dioxide—DUO2) is used to produce multifunction shielded casks. Several years after discharge, spent

  2. Study of 5f electron states in Uranium Dioxide using Inelastic Neutron Spectroscopy

    NASA Astrophysics Data System (ADS)

    Rajaram, Ramya; Kern, Sanford; Lander, Gerry; McQueeney, Rob; Nakotte, Heinz

    2003-03-01

    Uranium dioxide, a nuclear fuel material is one of the commonly studied actinide compounds and the nature of their 5f electrons, their degree of localization and their high-temperature thermodynamic properties have been studied in detail. Knowledge of the crystal field potential is an important part of these studies. High-resolution, high-energy transfer inelastic neutron scattering has been used to study the crystal field excitations in Uranium Dioxide. These measurements were made on PHAROS at the Los Alamos Neutron Science Center, Los Alamos National Laboratory. Since all the dipole allowed transitions in the free ion ground manifold are known, the experiments allow a complete determination of the crystal field potential and 5f-electron eigenstates in Uranium Dioxide. The ground state is accurately given by intermediate-coupling approximation with little changes by J-mixing effects. Below the Neel temperature of 30.8 K, a splitting of the cubic crystal field levels is observed. The splittings are shown to be consistent with the triple-k model.

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

    SciTech Connect

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

    2014-01-01

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

  4. Contribution of ion emission to sputtering of uranium dioxide by highly charged ions

    Microsoft Academic Search

    S. Boudjadar; F. Haranger; T. Jalowy; A. Robin; B. Ban d’Etat; T. Been; Ph. Boduch; H. Lebius; B. Manil; L. Maunoury; H. Rothard

    2005-01-01

    Measurements of the cluster size (n) distribution of secondary \\u000a(UOx)+n ions from sputtering of uranium dioxide (UO2) by \\u000aNe8+, Ar8+ and Xeq+ ions (q=10, 23) at fixed kinetic energy \\u000a(81 keV) have been performed with a time-of-flight mass spectrometer. The \\u000acluster ion yields Y follow a power law Y(n)~nd with \\u000a-2.1

  5. Migration of defect clusters and xenon-vacancy clusters in uranium dioxide

    SciTech Connect

    Chen, Dong; Gao, Fei; Deng, Huiqiu; Hu, Wangyu; Sun, Xin

    2014-07-01

    The possible transition states, minimum energy paths and migration mechanisms of defect clusters and xenon-vacancy defect clusters in uranium dioxide have been investigated using the dimer and the nudged elastic-band methods. The nearby O atom can easily hop into the oxygen vacancy position by overcoming a small energy barrier, which is much lower than that for the migration of a uranium vacancy. A simulation for a vacancy cluster consisting of two oxygen vacancies reveals that the energy barrier of the divacancy migration tends to decrease with increasing the separation distance of divacancy. For an oxygen interstitial, the migration barrier for the hopping mechanism is almost three times larger than that for the exchange mechanism. Xe moving between two interstitial sites is unlikely a dominant migration mechanism considering the higher energy barrier. A net migration process of a Xe-vacancy pair containing an oxygen vacancy and a xenon interstitial is identified by the NEB method. We expect the oxygen vacancy-assisted migration mechanism to possibly lead to a long distance migration of the Xe interstitials in UO2. The migration of defect clusters involving Xe substitution indicates that Xe atom migrating away from the uranium vacancy site is difficult.

  6. Microbeam x-ray absorption spectroscopy study of chromium in large-grain uranium dioxide fuel

    NASA Astrophysics Data System (ADS)

    Mieszczynski, C.; Kuri, G.; Bertsch, J.; Martin, M.; Borca, C. N.; Delafoy, Ch; Simoni, E.

    2014-09-01

    Synchrotron-based microprobe x-ray absorption spectroscopy (XAS) has been used to study the local atomic structure of chromium in chromia-doped uranium dioxide (UO2) grains. The specimens investigated were a commercial grade chromia-doped UO2 fresh fuel pellet, and materials from a spent fuel pellet of the same batch, irradiated with an average burnup of ~40?MW d kg-1. Uranium L3-edge and chromium K-edge XAS have been measured, and the structural environments of central uranium and chromium atoms have been elucidated. The Fourier transform of uranium L3-edge extended x-ray absorption fine structure shows two well-defined peaks of U-O and U-U bonds at average distances of 2.36 and 3.83?Å. Their coordination numbers are determined as 8 and 11, respectively. The chromium Fourier transform extended x-ray absorption fine structure of the pristine UO2 matrix shows similar structural features with the corresponding spectrum of the irradiated spent fuel, indicative of analogous chromium environments in the two samples studied. From the chromium XAS experimental data, detectable next neighbor atoms are oxygen and uranium of the cation-substituted UO2 lattice, and two distinct subshells of chromium and oxygen neighbors, possibly because of undissolved chromia particles present in the doped fuels. Curve-fitting analyses using theoretical amplitude and phase-shift functions of the closest Cr-O shell and calculations with ab initio computer code FEFF and atomic clusters generated from the chromium-dissolved UO2 structure have been carried out. There is a prominent reduction in the length of the adjacent Cr-O bond of about 0.3?Å in chromia-doped UO2 compared with the ideal U-O bond length in standard UO2 that would be expected because of the change in effective Coulomb interactions resulting from replacing U4+ with Cr3+ and their ionic size differences. The contraction of shortest Cr-U bond is ~0.1?Å relative to the U-U bond length in bulk UO2. The difference in the local chromium environment between fresh and irradiated UO2 is discussed based on the comparison of quantitative structural information obtained from the two chromia-doped fuel samples analyzed.

  7. Measurement of fission gas release rates from a uranium dioxide fuel pin during irradiation in a fast reactor

    Microsoft Academic Search

    W. B. Bremner; A. B. G. Washington

    1973-01-01

    An experiment carried out in the Dounreay fast reactor to measure ; continuously the fission gases released from a long uranium dioxide fuel pin ; irradiated to a burn-up of 2% is described. The gases were swept by a helium ; purge from the pin to the reactor top where they were analyzed by bottle sampling ; and in line

  8. Carbonate effects on hexavalent uranium removal from water by nanocrystalline titanium dioxide.

    PubMed

    Wazne, Mahmoud; Meng, Xiaoguang; Korfiatis, George P; Christodoulatos, Christos

    2006-08-10

    A novel nanocrystalline titanium dioxide was used to treat depleted uranium (DU)-contaminated water under neutral and alkaline conditions. The novel material had a total surface area of 329 m(2)/g, total surface site density of 11.0 sites/nm(2), total pore volume of 0.415 cm(3)/g and crystallite size of 6.0 nm. It was used in batch tests to remove U(VI) from synthetic solutions and contaminated water. However, the capacity of the nanocrystalline titanium dioxide to remove U(VI) from water decreased in the presence of inorganic carbonate at pH > 6.0. Adsorption isotherms, Fourier transform infrared (FTIR) spectroscopy, and surface charge measurements were used to investigate the causes of the reduced capacity. The surface charge and the FTIR measurements suggested that the adsorbed U(VI) species was not complexed with carbonate at neutral pH values. The decreased capacity of titanium dioxide to remove U(VI) from water in the presence of carbonate at neutral to alkaline pH values was attributed to the aqueous complexation of U(VI) by inorganic carbonate. The nanocrystalline titanium dioxide had four times the capacity of commercially available titanium dixoide (Degussa P-25) to adsorb U(VI) from water at pH 6 and total inorganic carbonate concentration of 0.01 M. Consequently, the novel material was used to treat DU-contaminated water at a Department of Defense (DOD) site. PMID:16352391

  9. Characteristics of a Mixed Thorium-Uranium Dioxide High-Burnup Fuel

    SciTech Connect

    J. S. Herring; P. E. MacDonald

    1999-06-01

    Future nuclear fuels must satisfy three sets of requirements: longer times between refueling; concerns for weapons proliferation; and development of a spent fuel form more suitable for direct geologic disposal. This project has investigated a fuel consisting of mixed thorium and uranium dioxide to satisfy these requirements. Results using the SCALE 4.3 code system indicated that the mixed Th-U fuel could be burned to 72 MWD/kg or 100 MWD/kg using 25% of 35% UO2 respectively. The uranium remained below 20% total fissile fraction throughout the cycle, making it unusable for weapons. Total plutonium production per MWD was a factor of 4.5 less in the Th-U fuel than in the conventional fuel; Pu-239 production per MWD was a factor of 6.5 less; and the plutonium produced was high in Pu-238, leading to a decay heat 5 times greater than that from plutonium derived from conventional fuel and 40 times greater than weapons grade plutonium. High decay heat would require active cooling of any crude weapon, lest the components surrounding the plutonium be melted. Spontaneous neutron production for plutonium from Th-U fuel was 2.3 times greater than that from conventional fuel and 15 times greater than that from weapons grade plutonium. High spontaneous neutron production drastically limits the probable yield of a crude weapon. Because ThO2 is the highest oxide of thorium, while UO2 can be oxidized further to U3O8, ThO2-UO2 fuel may be a superior wasteform if the spent fuel is ever to be exposed to oxygenated water. Even if the cost of fabricating the mixed Th-U fuel is $100/kg greater, the cost of the Th-U fuel is 13% to 15% less than that of the fuels using uranium only.

  10. Characteristics of a Mixed Thorium - Uranium Dioxide High-Burnup Fuel

    SciTech Connect

    Herring, James Stephen; Mac Donald, Philip Elsworth

    1999-06-01

    Future nuclear fuel must satisfy three sets of requirements: longer times between refueling; concerns for weapons proliferation; and development of a spent fuel form more suitable for direct geologic disposal. This project has investigated a fuel consisting of mixed thorium and uranium dioxide to satisfy these requirements. Results using the SCALE 4.3 code system indicated that the mixed Th-U fuel could be burned to 72 MWD/kg or 100 MWD/kg using 25% and 35% UO2 respectively. The uranium remained below 20 % total fissile fraction throughout the cycle, making it unusable for weapons. Total plutonium production per MWD was a factor of 4.5 less in the Th-U fuel than in the conventional fuel; Pu-239 production per MWD was a factor of 6.5 less; and the plutonium produced was high in Pu-238, leading to a decay heat 5 times greater than that from plutonium derived from conventional fuel and 40 times greater than weapons grade plutonium. High decay heat would require active cooling of any crude weapon, lest the components surrounding the plutonium be melted. Spontaneous neutron production for plutonium from Th-U fuel was 2.3 times greater than that from conventional fuel and 15 times greater than that from weapons grade plutonium. High spontaneous neutron production drastically limits the probable yield of a crude weapon. Because ThO2 is the highest oxide of thorium, while UO2 can be oxidized further to U3O8, ThO2- UO2 fuel may be a superior wasteform if the spent fuel is ever to be exposed to oxygenated water. Even if the cost of fabricating the mixed Th-U fuel is $100/kg greater, the cost of the Th-U fuel is 13% to 25% less than that of the fuels using uranium only.

  11. Reactions of plutonium dioxide with water and oxygen-hydrogen mixtures: Mechanisms for corrosion of uranium and plutonium

    SciTech Connect

    Haschke, John M.; Allen, Thomas H.; Morales, Luis A.

    1999-06-18

    Investigation of the interactions of plutonium dioxide with water vapor and with an oxygen-hydrogen mixture show that the oxide is both chemically reactive and catalytically active. Correspondence of the chemical behavior with that for oxidation of uranium in moist air suggests that similar catalytic processes participate in the mechanism of moisture-enhanced corrosion of uranium and plutonium. Evaluation of chemical and kinetic data for corrosion of the metals leads to a comprehensive mechanism for corrosion in dry air, water vapor, and moist air. Results are applied in confirming that the corrosion rate of Pu in water vapor decreases sharply between 100 and 200 degrees C.

  12. Monte Carlo Criticality Analysis of Simple Geometrics COntaining Tungsten Rhenium Alloys Engrained with Uranium Dioxide and Uranium Mononitride

    SciTech Connect

    Jonathan A. Webb; Indrajit Charit

    2011-08-01

    The critical mass and dimensions of simple geometries containing highly enriched uraniumdioxide (UO2) and uraniummononitride (UN) encapsulated in tungsten-rhenium alloys are determined using MCNP5 criticality calculations. Spheres as well as cylinders with length to radius ratios of 1.82 are computationally built to consist of 60 vol.% fuel and 40 vol.% metal matrix. Within the geometries the uranium is enriched to 93 wt.% uranium-235 and the rhenium content within the metal alloy was modeled over a range of 0 to 30 at.%. The spheres containing UO2 were determined to have a critical radius of 18.29 cm to 19.11 cm and a critical mass ranging from 366 kg to 424 kg. The cylinders containing UO2 were found to have a critical radius ranging from 17.07 cm to 17.844 cm with a corresponding critical mass of 406 kg to 471 kg. Spheres engrained with UN were determined to have a critical radius ranging from 14.82 cm to 15.19 cm and a critical mass between 222 kg and 242 kg. Cylinders which were engrained with UN were determined to have a critical radius ranging from 13.811 cm to 14.155 cm with a corresponding critical mass of 245 kg to 267 kg. The critical geometries were also computationally submerged in a neutronaically infinite medium of fresh water to determine the effects of rhenium addition on criticality accidents due to water submersion. The monte carlo analysis demonstrated that rhenium addition of up to 30 at.% can reduce the excess reactivity due to water submersion by up to $5.07 for UO2 fueled cylinders, $3.87 for UO2 fueled spheres and approximately $3.00 for UN fueled spheres and cylinders.

  13. First principles computational modeling of the surface properties of uranium dioxide

    NASA Astrophysics Data System (ADS)

    Hoover, Megan

    The interaction of uranium dioxide (UO2) with environmental elements occurs at its exposed surface and a fundamental understanding of this interaction process begins at the atomic scale. In this regard, atomic scale modeling of the properties of clean and adsorbate-covered uranium dioxide (UO2) surfaces can be used to elucidate UO2 surface mechanisms such as corrosion and the formation of complex species via environmental gas adsorption. In this thesis, structural and electronic properties of clean and adsorbatecovered low index UO2 surfaces were modeled using regular and hybrid density functional theory. Specifically, the properties of the clean (111) and (110) surfaces were modeled with hybrid density functional theory. To gain some insight into the surface oxidation of UO2, we performed preliminary modeling studies on the interaction of atomic oxygen with the UO2 (111) surface using density functional theory and hybrid density functional theory. For the clean surface, the evolution of the work function, surface energy, incremental energy, and band gap with respect to the system size was studied. We observed that at five formula units and beyond the surface properties of UO2 converge. The estimated work function, surface energy, and band gap of the (111) surface were 3.5 eV, 0.97 J/m2, and 1.2 eV respectively; the corresponding values for the (110) surface were 2.2 eV, 1.76 J/m2, and 0.65 eV respectively. The localization of the 5f electron states is pronounced at the top surface layer while bulk-like behavior is exhibited at and below the subsurface layer. The Mott-Hubbard type insulating behavior in the bulk is retained in the surfaces, albeit with a smaller band gap. The adsorption of O in the UO2 (111) surface indicates that UO2 oxidation is a stable process. The top site is the preferred adsorption site with adsorption energy of 5.37 eV. The presence of the adsorbate results in the change of the electronic work function by 2.56 eV, implying charge transfer from U to O. The analysis of the electronic density of states indicates hybridization between the O adsorbate 2p electron states and the neighboring U 5f electron states. Furthermore, the presence of the adsorbate did not alter the Mott-Hubbard insulating behavior seen in the bulk crystal and clean surface.

  14. Percutaneous absorption of uranium compounds.

    PubMed

    de Rey, B M; Lanfranchi, H E; Cabrini, R L

    1983-04-01

    Percutaneous absorption of soluble and insoluble uranium compounds has been induced in order to obtain information on penetration routes and the tissue injury produced by uranium salts. The high electron density of uranium provided a reliable way to visualize, by electron microscopy, the precise localization of the heavy compounds within the tissues. Few minutes after topical application of uranyl nitrate, dense deposits of uranium were observed at the epidermal barrier level. A few hours later, dense deposits were seen filling the intercellular spaces and were also scattered in the cytoplasm and nucleus. Mortality and body weight measurements indicated the high toxicity of uranyl nitrate and ammonium uranyl tricarbonate; uranyl acetate and ammonium diuranate were less toxic. As no penetration was achieved after uranium dioxide, no variations were detected on these parameters. PMID:6832127

  15. Design of a uranium-dioxide powder spheroidization system by plasma processing

    NASA Astrophysics Data System (ADS)

    Cavender, Daniel

    The plasma spheroidization system (PSS) is the first process in the development of a tungsten-uranium dioxide (W-UO2) ceramic-metallic (cermet) fuel for nuclear thermal rocket (NTR) propulsion. For the purposes of fissile fuel retention, UO2 spheroids ranging in size from 50 - 100 micrometers (?m) in diameter will be encapsulated in a tungsten shell. The PSS produces spherical particles by melting angular stock particles in an argon-hydrogen plasma jet where they become spherical due to surface tension. Surrogate CeO 2 powder was used in place of UO2 for system and process parameter development. Stock and spheroidized powders were micrographed using optical and scanning electron microscopy and evaluated by statistical methods to characterize and compare the spherocity of pre and post process powders. Particle spherocity was determined by irregularity parameter. Processed powders showed a statistically significant improvement in spherocity, with greater that 60% of the examined particles having an irregularity parameter of equal to or lower than 1.2, compared to stock powder.

  16. A combined theoretical and experimental investigation of uranium dioxide under high static pressure

    NASA Astrophysics Data System (ADS)

    Crowhurst, J. C.; Jeffries, J. R.; Åberg, D.; Zaug, J. M.; Dai, Z. R.; Siekhaus, W. J.; Teslich, N. E.; Holliday, K. S.; Knight, K. B.; Nelson, A. J.; Hutcheon, I. D.

    2015-07-01

    We have investigated the behavior of uranium dioxide (UO2) under high static pressure using a combination of experimental and theoretical techniques. We have made Raman spectroscopic measurements up to 87 GPa, electrical transport measurements up to 50 GPa from 10 K to room temperature, and optical transmission measurements up to 28 GPa. We have also carried out theoretical calculations within the GGA + U framework. We find that Raman frequencies match to a large extent, theoretical predictions for the cotunnite (Pnma) structure above 30 GPa, but at higher pressures some behavior is not captured theoretically. The Raman measurements also imply that the low-pressure fluorite phase coexists with the cotunnite phase up to high pressures, consistent with earlier reports. Electrical transport measurements show that the resistivity decreases by more than six orders of magnitude with increasing pressure up to 50 GPa but that the material never adopts archetypal metallic behavior. Optical transmission spectra show that while UO2 becomes increasingly opaque with increasing pressure, a likely direct optical band gap of more than 1 eV exists up to at least 28 GPa. Together with the electrical transport measurements, we conclude that the high pressure electrical conductivity of UO2 is mediated by variable-range hopping.

  17. Computational modeling of the surface properties of uranium dioxide using hybrid DFT

    NASA Astrophysics Data System (ADS)

    Hoover, Megan; Atta-Fynn, Raymond

    2014-03-01

    Computational modeling of processes such as corrosion and the interaction of environmental impurities with the surfaces of actinide materials are important to the understanding of remediation processes for actinide-based nuclear waste from the biosphere. However, accurate modeling of bare surfaces of actinide materials is a necessary precursor to accurate modeling of surface interactions. This talk will be focused on atomistic modeling of uranium dioxide (UO2) surfaces. The theoretical formalism is all-electron hybrid Density Functional Theory (DFT) based on the full-potential linearized augmented plane wave plus local basis method. Specifically, we computed the surface energies, work functions, incremental energies, and electronic band gaps for periodic slab structures for the (110) and (111) surfaces of UO2. We observed that the anti-ferromagnetic semiconducting behavior in the bulk structure is retained in the surface structures. The convergence of surface properties with respect to slab thickness will be discussed. The trends in the surface electronic structures, particularly the localized behavior of the U 5 f electrons, in comparison with the bulk structure will also be elucidated.

  18. A combined theoretical and experimental investigation of uranium dioxide under high static pressure.

    PubMed

    Crowhurst, J C; Jeffries, J R; Åberg, D; Zaug, J M; Dai, Z R; Siekhaus, W J; Teslich, N E; Holliday, K S; Knight, K B; Nelson, A J; Hutcheon, I D

    2015-07-01

    We have investigated the behavior of uranium dioxide (UO2) under high static pressure using a combination of experimental and theoretical techniques. We have made Raman spectroscopic measurements up to 87 GPa, electrical transport measurements up to 50 GPa from 10 K to room temperature, and optical transmission measurements up to 28 GPa. We have also carried out theoretical calculations within the GGA + U framework. We find that Raman frequencies match to a large extent, theoretical predictions for the cotunnite (Pnma) structure above 30 GPa, but at higher pressures some behavior is not captured theoretically. The Raman measurements also imply that the low-pressure fluorite phase coexists with the cotunnite phase up to high pressures, consistent with earlier reports. Electrical transport measurements show that the resistivity decreases by more than six orders of magnitude with increasing pressure up to 50 GPa but that the material never adopts archetypal metallic behavior. Optical transmission spectra show that while UO2 becomes increasingly opaque with increasing pressure, a likely direct optical band gap of more than 1 eV exists up to at least 28 GPa. Together with the electrical transport measurements, we conclude that the high pressure electrical conductivity of UO2 is mediated by variable-range hopping. PMID:26053594

  19. Computer simulation of structural modifications induced by highly energetic ions in uranium dioxide

    NASA Astrophysics Data System (ADS)

    Sasajima, Y.; Osada, T.; Ishikawa, N.; Iwase, A.

    2013-11-01

    The structural modification caused by the high-energy-ion irradiation of single-crystalline uranium dioxide was simulated by the molecular dynamics method. As the initial condition, high kinetic energy was supplied to the individual atoms within a cylindrical region of nanometer-order radius located in the center of the specimen. The potential proposed by Basak et al. [C.B. Basak, A.K. Sengupta, H.S. Kamath, J. Alloys Compd. 360 (2003) 210-216] was utilized to calculate interaction between atoms. The supplied kinetic energy was first spent to change the crystal structure into an amorphous one within a short period of about 0.3 ps, then it dissipated in the specimen. The amorphous track radius Ra was determined as a function of the effective stopping power gSe, i.e., the kinetic energy of atoms per unit length created by ion irradiation (Se: electronic stopping power, g: energy transfer ratio from stopping power to lattice vibration energy). It was found that the relationship between Ra and gSe follows the relation Ra2=aln(gS)+b. Compared to the case of Si and ?-cristobalite single crystals, it was harder to produce amorphous track because of the long range interaction between U atoms.

  20. Oxygen transport in off-stoichiometric uranium dioxide mediated by defect clustering dynamics.

    PubMed

    Yu, Jianguo; Bai, Xian-Ming; El-Azab, Anter; Allen, Todd R

    2015-03-01

    Oxygen transport is central to many properties of oxides such as stoichiometric changes, phase transformation, and ionic conductivity. In this paper, we report a mechanism for oxygen transport in uranium dioxide (UO2) in which the kinetics is mediated by defect clustering dynamics. In particular, the kinetic Monte Carlo method has been used to investigate the kinetics of oxygen transport in UO2 under the condition of creation and annihilation of oxygen vacancies and interstitials as well as oxygen interstitial clustering, with variable off-stoichiometry and temperature conditions. It is found that in hypo-stoichiometric UO(2-x), oxygen transport is well described by the vacancy diffusion mechanism while in hyper-stoichiometric UO(2+x), oxygen interstitial cluster diffusion contributes significantly to oxygen transport kinetics, particularly at high temperatures and high off-stoichiometry levels. It is also found that di-interstitial clusters and single interstitials play dominant roles in oxygen diffusion while other larger clusters have negligible contributions. However, the formation, coalescence, and dissociation of these larger clusters indirectly affects the overall oxygen diffusion due to their interactions with mono and di-interstitials, thus providing an explanation of the experimental observation of saturation or even drop of oxygen diffusivity at high off-stoichiometry. PMID:25747097

  1. Atomistic study of porosity impact on phonon driven thermal conductivity: Application to uranium dioxide

    SciTech Connect

    Colbert, Mehdi; Ribeiro, Fabienne [Institut de Radioprotection et de Sûreté Nucléaire, IRSN, Bat. 702, CE Cadarache, BP3-13115 Saint Paul-Lez-Durance Cedex (France); Tréglia, Guy [Aix-Marseille Université, CNRS, CINaM UMR 7325, 13288 Marseille (France)

    2014-01-21

    We present here an analytical method, based on the kinetic theory, to determine the impact of defects such as cavities on the thermal conductivity of a solid. This approach, which explicitly takes into account the effects of internal pore surfaces, will be referred to as the Phonon Interface THermal cONductivity (PITHON) model. Once exposed in the general case, this method is then illustrated in the case of uranium dioxide. It appears that taking properly into account these interface effects significantly modifies the temperature and porosity dependence of thermal conductivity with respect to that issued from either micromechanical models or more recent approaches, in particular, for small cavity sizes. More precisely, it is found that if the mean free path appears to have a major effect in this system in the temperature and porosity distribution range of interest, the variation of the specific heat at the surface of the cavity is predicted to be essential at very low temperature and small sizes for sufficiently large porosity.

  2. Uranium industry annual 1998

    SciTech Connect

    NONE

    1999-04-22

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

  3. Interaction mechanisms between uranium(VI) and rutile titanium dioxide: from single crystal to powder.

    PubMed

    Vandenborre, Johan; Drot, Romuald; Simoni, Eric

    2007-02-19

    This paper is devoted to the study of the mechanisms of interaction between uranyl ion and rutile TiO2. Among the radionuclides of interest, U(VI) can be considered as a model of the radionuclides oxo-cations. The substrate under study here is the rutile titanium dioxide (TiO2) which is an interesting candidate as a methodological solid since it can be easily found as powder and as manufactured single crystals. This material presents also a wide domain of stability as a function of pH. Then, it allows the study of the retention processes on well-defined crystallographic planes, which can lead to a better understanding of the surface reaction mechanisms. Moreover, it is well-established that the (110) crystallographic orientation is dominating the surface chemistry of the rutile powder. Therefore, the spectroscopic results obtained for the U(VI)/rutile (110) system and other relevant crystallographic orientations were used to have some insight on the nature of the uranium surface complexes formed on rutile powder. This goal was achieved by using time-resolved laser-induced fluorescence spectroscopy (TRLFS) which allows the investigation, at a molecular scale, of the nature of the reactive surface sites as well as the surface species. For rutile surfaces, oxygen atoms can be 3-fold, 2-fold (bridging oxygens), or single-fold (top oxygens) coordinated to titanium atoms. However, among these three types of surface oxygen atoms, the 3-fold coordinated ones are not reactive toward water molecules or aqueous metallic cations. This study led to conclude on the presence of two uranium(VI) surface complexes: the first one corresponds to the sorption of aquo UO22+ ion sorbed on two bridging oxygen atoms, while the second one, which is favored at higher surface coverages, corresponds to the retention of UO22+ by one bridging and one top oxygen atom. Thus, the approach presented in this paper allows the establishment of experimental constraints that have to be taken into account in the modeling of the sorption mechanisms. PMID:17291119

  4. ECONOMICS OF UNIRRADIATED PROCESSING PHASES OF URANIUM FUEL CYCLES

    Microsoft Academic Search

    J. P. Murray; F. S. Patton; R. F. Hibbs; W. L. Griffith

    1958-01-01

    Expanding reactor programs prescnt industrial opportunities in their ; fuel processing phases. This . paper considers the manufacture of ; unirradiated uranium fuel materials, including the conversion of uranium ; hexafluoride to uranium metal, uranium dioxide, etc.; their subsequent ; fabrication into fuel elements; and the processing and recycle of accrued scrap. ; The intent is to offer potentinl processors

  5. Partition of soluble fission products between the grey phase, ZrO2 and uranium dioxide

    NASA Astrophysics Data System (ADS)

    Cooper, M. W. D.; Middleburgh, S. C.; Grimes, R. W.

    2013-07-01

    The energies to remove fission products from UO2 or UO2+x and incorporate them into BaZrO3, SrZrO3 (grey phase constituent phases) and ZrO2 have been calculated using atomistic scale simulation. These energies provide the thermodynamic drive for partition of soluble fission products between UO2 or UO2+x and these secondary oxide constituents of the fuel system. Tetravalent cation partition into BaZrO3, SrZrO3 and ZrO2 was only preferable for species with smaller radii than Zr4+, regardless of uranium dioxide stoichiometry. Under stoichiometric conditions both the larger and the smaller trivalent cations were found to segregate to BaZrO3 but only the smaller fuel additive elements Cr3+ and Fe3+ segregate to SrZrO3. Partition from UO2+x was always unfavourable for trivalent cations. Additions of excess Cr3+ (as a fuel additive) are predicted make the partition into BaZrO3 and SrZrO3 more favourable from UO2 for the larger trivalent cations. Trivalent fission products with radii smaller than or equal to that of Sm3+ were identified to segregate into ZrO2 only from UO2. No segregation to SrO or BaO is predicted. Conventional Kröger-Vink notation does not allow for distinction between oxygen sites in the UO2 and the secondary phases. As such, from now on we will distinguish all defects in the UO2 lattice with a line, e.g. MUׯ.

  6. Ex-Reactor Determination of Thermal Gap Conductance Between Uranium Dioxide and Zircaloy-4

    SciTech Connect

    Garnier, J.; Begej, S.

    1980-07-01

    An ex-reactor study of the thermal gap conductance between Uranium Dioxide (UO{sub 2}) and Zircaloy-4 (Zr4) was performed under varying conditions of gas pressure (0.1 to 7 MPa); temperature (283 to 673 K); gas composition (He (100); Ar (100); He:Ar (51.79:48.21); and He:Xe (89.4:10.6)); and, average mean-plane separation distance D{sub mp} = 5.9 {micro}m (light contact); and, D{sub mp} = 23.1 {micro}m). In this report a description of the high pressure autoclave, specimen holder and associated apparatus is given together with experimental results. In conjunction with the experimental apparatus an assessment of determinant and indeterminant errors is made. In this report the predicted gap conductance based on the "ideal" expression for the gap conductance, H{sub g} = K{sub gas}/(d + g{sub 1} + g{sub 2}) and assuming D{sub m}p = d and g{sub 1} = g{sub 2}, is compared to the H{sub g} results and found not to be in agreement. Use of the ideal gap conductance expression under these conditions is seen to under-estimate the value of H{sub g} results. A discussion of possible reasons for the differences between the observed and predicted behavior is made. In addition to experimental errors resulting from gaseous convection, a detailed examination of the ideal gap conductance expression reveals that the basic assumptions (upon which the ideal gap conductance expression is derived) are not valid for real surfaces in close proximity and/or contact.

  7. DEPLETED URANIUM TECHNICAL WORK

    EPA Science Inventory

    The Depleted Uranium Technical Work is designed to convey available information and knowledge about depleted uranium to EPA Remedial Project Managers, On-Scene Coordinators, contractors, and other Agency managers involved with the remediation of sites contaminated with this mater...

  8. Uranium industry annual 1995

    SciTech Connect

    NONE

    1996-05-01

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

  9. PROPERTIES OF URANIUM CARBIDES

    Microsoft Academic Search

    W. Chubb; R. F. Dickerson

    1962-01-01

    Properties of uranium carbides are reviewed and brought up to date. ; Photographs and photomicrographs of uranium carbides fabricated by melting and ; casting techniques and by powder metallurgy techniques are presented. Recent ; data confirm that uranium monocarbide has metallic conductivity (a thermal ; conductivity of approximately 0.055 cal\\/sec-cm- deg C and a resistivity of ; approximately 35 microhm-cm)

  10. Depleted Uranium Technical Brief

    E-print Network

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

  11. Screened Coulomb interaction calculations: cRPA implementation and applications to dynamical screening and self-consistency in uranium dioxide and cerium

    NASA Astrophysics Data System (ADS)

    Amadon, Bernard; Applencourt, Thomas; Bruneval, Fabien

    2014-03-01

    We report an implementation of the constrained random phase approximation (cRPA) method within the projector augmented-wave framework. It allows for the calculation of the screened interaction in the same Wannier orbitals as our recent DFT+U and DFT+DMFT implementations. We present calculations of the dynamical Coulomb screened interaction in uranium dioxide and ? and ? cerium on Wannier functions. We show that a self-consistent calculation of the static screened interaction in DFT+U together with a consistent Wannier basis is mandatory for ? cerium and uranium dioxide. We emphasize that a static approximation for the screened interaction in ? cerium is too drastic.

  12. Method for converting uranium oxides to uranium metal

    DOEpatents

    Duerksen, Walter K. (Norris, TN)

    1988-01-01

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

  13. Investigations of ion-irradiated uranium dioxide nuclear fuel with laser-assisted atom probe tomography

    NASA Astrophysics Data System (ADS)

    Valderrama, Billy

    Performance in commercial light water reactors is dictated by the ability of its fuel material, uranium dioxide (UO2), to transport heat generated during the fission process. It is widely known that the service lifetime is limited by irradiation-induced microstructural changes that degrade the thermal performance of UO2. Studying the role of complex, often interacting mechanisms that occur during the early stages of microstructural evolution presents a challenge. Phenomena of particular interest are the segregation of fission products to form bubbles and their resultant effect on grain boundary (GB) mobility, and the effect of irradiation on fuel stoichiometry. Each mechanism has a profound consequence on fuel thermal conductivity. Several advanced analytical techniques, such as transmission electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, etc. have been used to study these mechanisms. However, they each have limitations and cannot individually provide the necessary information for deeper understanding. One technique that has been under utilized is atom probe tomography (APT), which has a unique ability to spatially resolve small-scale chemical variations. APT uses the principle of field ionization to evaporate surface ions for chemical analysis. For low electrical conductivity systems, a pulsed laser is used to thermally assist in the evaporation process. One factor complicating the analysis is that laser-material interactions are poorly understood for oxide materials and literature using this technique with UO2 is lacking. Therefore, an initial systematic study to identify the optimal conditions for the analysis of UO2 using laser-assisted APT was conducted. A comparative study on the evaporation behavior between CeO2 and UO2 was followed. CeO2 was chosen due to its technological relevancy and availability of comparative studies with laser-assisted APT. Dissimilar evaporation behavior between these materials was identified and attributed to differences in laser absorption, oxide stability, and thermal conductivity between the two materials. After the conditions were identified, APT was utilized to study the role of temperature and GB structure on the segregation of Kr. Results indicate that high angle GBs contain more Kr relative to low angle GBs. The methodology presented can be applied to investigate small-scale chemical changes in other oxide materials.

  14. Welding of uranium and uranium alloys

    SciTech Connect

    Mara, G.L.; Murphy, J.L.

    1982-03-26

    The major reported work on joining uranium comes from the USA, Great Britain, France and the USSR. The driving force for producing this technology base stems from the uses of uranium as a nuclear fuel for energy production, compact structures requiring high density, projectiles, radiation shielding, and nuclear weapons. This review examines the state-of-the-art of this technology and presents current welding process and parameter information. The welding metallurgy of uranium and the influence of microstructure on mechanical properties is developed for a number of the more commonly used welding processes.

  15. Bioremediation of uranium contamination with enzymatic uranium reduction

    USGS Publications Warehouse

    Lovley, D.R.; Phillips, E.J.P.

    1992-01-01

    Enzymatic uranium reduction by Desulfovibrio desulfuricans readily removed uranium from solution in a batch system or when D. desulfuricans was separated from the bulk of the uranium-containing water by a semipermeable membrane. Uranium reduction continued at concentrations as high as 24 mM. Of a variety of potentially inhibiting anions and metals evaluated, only high concentrations of copper inhibited uranium reduction. Freeze-dried cells, stored aerobically, reduced uranium as fast as fresh cells. D. desulfuricans reduced uranium in pH 4 and pH 7.4 mine drainage waters and in uraniumcontaining groundwaters from a contaminated Department of Energy site. Enzymatic uranium reduction has several potential advantages over other bioprocessing techniques for uranium removal, the most important of which are as follows: the ability to precipitate uranium that is in the form of a uranyl carbonate complex; high capacity for uranium removal per cell; the formation of a compact, relatively pure, uranium precipitate.

  16. Preparation of uranium compounds

    DOEpatents

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

    2013-02-19

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

  17. Uranium industry annual 1993

    SciTech Connect

    Not Available

    1994-09-01

    Uranium production in the United States has declined dramatically from a peak of 43.7 million pounds U{sub 3}O{sub 8} (16.8 thousand metric tons uranium (U)) in 1980 to 3.1 million pounds U{sub 3}O{sub 8} (1.2 thousand metric tons U) in 1993. This decline is attributed to the world uranium market experiencing oversupply and intense competition. Large inventories of uranium accumulated when optimistic forecasts for growth in nuclear power generation were not realized. The other factor which is affecting U.S. uranium production is that some other countries, notably Australia and Canada, possess higher quality uranium reserves that can be mined at lower costs than those of the United States. Realizing its competitive advantage, Canada was the world`s largest producer in 1993 with an output of 23.9 million pounds U{sub 3}O{sub 8} (9.2 thousand metric tons U). The U.S. uranium industry, responding to over a decade of declining market prices, has downsized and adopted less costly and more efficient production methods. The main result has been a suspension of production from conventional mines and mills. Since mid-1992, only nonconventional production facilities, chiefly in situ leach (ISL) mining and byproduct recovery, have operated in the United States. In contrast, nonconventional sources provided only 13 percent of the uranium produced in 1980. ISL mining has developed into the most cost efficient and environmentally acceptable method for producing uranium in the United States. The process, also known as solution mining, differs from conventional mining in that solutions are used to recover uranium from the ground without excavating the ore and generating associated solid waste. This article describes the current ISL Yang technology and its regulatory approval process, and provides an analysis of the factors favoring ISL mining over conventional methods in a declining uranium market.

  18. Uranium extraction process

    SciTech Connect

    Rose, M.A.

    1983-05-03

    Uranium is extracted from wet process phosphoric acid by extraction with a mixture of a diorganophosphate and a neutral phosphorus compound, which is preferably a triorgano phosphine oxide, in the presence of nitrate to form an organic extract layer containing uranium and an aqueous acid layer, which are separated.

  19. World Uranium Reserves

    NSDL National Science Digital Library

    James Hopf

    This American Energy Independence website provides a brief overview of potential supplies of uranium for nuclear energy. The author, nuclear engineer James Hopf, believes that there are large reserves of uranium available, and that more will be discovered if needed. Links to literature cited and related resources are included.

  20. Uranium: A Dentist's perspective

    PubMed Central

    Toor, R. S. S.; Brar, G. S.

    2012-01-01

    Uranium is a naturally occurring radionuclide found in granite and other mineral deposits. In its natural state, it consists of three isotopes (U-234, U-235 and U-238). On an average, 1% – 2% of ingested uranium is absorbed in the gastrointestinal tract in adults. The absorbed uranium rapidly enters the bloodstream and forms a diffusible ionic uranyl hydrogen carbonate complex (UO2HCO3+) which is in equilibrium with a nondiffusible uranyl albumin complex. In the skeleton, the uranyl ion replaces calcium in the hydroxyapatite complex of the bone crystal. Although in North India, there is a risk of radiological toxicity from orally ingested natural uranium, the principal health effects are chemical toxicity. The skeleton and kidney are the primary sites of uranium accumulation. Acute high dose of uranyl nitrate delays tooth eruption, and mandibular growth and development, probably due to its effect on target cells. Based on all previous research and recommendations, the role of a dentist is to educate the masses about the adverse effects of uranium on the overall as well as the dental health. The authors recommended that apart from the discontinuation of the addition of uranium to porcelain, the Public community water supplies must also comply with the Environmental Protection Agency (EPA) standards of uranium levels being not more than 30 ppb (parts per billion). PMID:24478959

  1. Uranium in river water

    Microsoft Academic Search

    M. R. Palmer; J. M. Edmond

    1993-01-01

    The concentration of dissolved uranium has been determined in over 250 river waters from the Orinoco, Amazon, and Ganges basins. Uranium concentrations are largely determined by dissolution of limestones, although weathering of black shales represents an important additional source in some basins. In shield terrains the level of dissolved U is transport limited. Data from the Amazon indicate that floodplains

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

    SciTech Connect

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

    2007-07-01

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

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

    E-print Network

    Hart, Gus

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

  4. 16. VIEW OF THE ENRICHED URANIUM RECOVERY SYSTEM. ENRICHED URANIUM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. VIEW OF THE ENRICHED URANIUM RECOVERY SYSTEM. ENRICHED URANIUM RECOVERY PROCESSED RELATIVELY PURE MATERIALS AND SOLUTIONS AND SOLID RESIDUES WITH RELATIVELY LOW URANIUM CONTENT. URANIUM RECOVERY INVOLVED BOTH SLOW AND FAST PROCESSES. (4/4/66) - Rocky Flats Plant, General Manufacturing, Support, Records-Central Computing, Southern portion of Plant, Golden, Jefferson County, CO

  5. Uranium triamidoamine chemistry.

    PubMed

    Gardner, Benedict M; Liddle, Stephen T

    2015-07-01

    Triamidoamine (Tren) complexes of the p- and d-block elements have been well-studied, and they display a diverse array of chemistry of academic, industrial and biological significance. Such in-depth investigations are not as widespread for Tren complexes of uranium, despite the general drive to better understand the chemical behaviour of uranium by virtue of its fundamental position within the nuclear sector. However, the chemistry of Tren-uranium complexes is characterised by the ability to stabilise otherwise reactive, multiply bonded main group donor atom ligands, construct uranium-metal bonds, promote small molecule activation, and support single molecule magnetism, all of which exploit the steric, electronic, thermodynamic and kinetic features of the Tren ligand system. This Feature Article presents a current account of the chemistry of Tren-uranium complexes. PMID:26035690

  6. 2013 Domestic Uranium Production Report

    E-print Network

    2013 Domestic Uranium Production Report May 2014 Independent Statistics & Analysis www.eia.gov U Administration | 2013 Domestic Uranium Production Report ii Contacts This report was prepared by the staff of the Renewables and Uranium Statistics Team, Office of Electricity, Renewables, and Uranium Statistics. Questions

  7. India's Worsening Uranium Shortage

    SciTech Connect

    Curtis, Michael M.

    2007-01-15

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

  8. Hot Hydrogen Testing of Tungsten-Uranium Dioxide (W-UO2) CERMET Fuel Materials for Nuclear Thermal Propulsion

    NASA Technical Reports Server (NTRS)

    Hickman, Robert; Broadway, Jeramie

    2014-01-01

    CERMET fuel materials are being developed at the NASA Marshall Space Flight Center for a Nuclear Cryogenic Propulsion Stage. Recent work has resulted in the development and demonstration of a Compact Fuel Element Environmental Test (CFEET) System that is capable of subjecting depleted uranium fuel material samples to hot hydrogen. A critical obstacle to the development of an NCPS engine is the high-cost and safety concerns associated with developmental testing in nuclear environments. The purpose of this testing capability is to enable low-cost screening of candidate materials, fabrication processes, and further validation of concepts. The CERMET samples consist of depleted uranium dioxide (UO2) fuel particles in a tungsten metal matrix, which has been demonstrated on previous programs to provide improved performance and retention of fission products1. Numerous past programs have utilized hot hydrogen furnace testing to develop and evaluate fuel materials. The testing provides a reasonable simulation of temperature and thermal stress effects in a flowing hydrogen environment. Though no information is gained about radiation damage, the furnace testing is extremely valuable for development and verification of fuel element materials and processes. The current work includes testing of subscale W-UO2 slugs to evaluate fuel loss and stability. The materials are then fabricated into samples with seven cooling channels to test a more representative section of a fuel element. Several iterations of testing are being performed to evaluate fuel mass loss impacts from density, microstructure, fuel particle size and shape, chemistry, claddings, particle coatings, and stabilizers. The fuel materials and forms being evaluated on this effort have all been demonstrated to control fuel migration and loss. The objective is to verify performance improvements of the various materials and process options prior to expensive full scale fabrication and testing. Post test analysis will include weight percent fuel loss, microscopy, dimensional tolerance, and fuel stability.

  9. Depleted uranium management alternatives

    SciTech Connect

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

    1994-08-01

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

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

    DOEpatents

    Kreuzmann, Alvin B. (Cincinnati, OH)

    1983-01-01

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

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

    DOEpatents

    Kreuzmann, A.B.

    1982-10-27

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

  12. Uranium purchases report 1994

    SciTech Connect

    NONE

    1995-07-01

    US utilities are required to report to the Secretary of Energy annually the country of origin and the seller of any uranium or enriched uranium purchased or imported into the US, as well as the country of origin and seller of any enrichment services purchased by the utility. This report compiles these data and also contains a glossary of terms and additional purchase information covering average price and contract duration. 3 tabs.

  13. Reprocessed uranium exposure and lung cancer risk.

    PubMed

    Canu, Irina Guseva; Jacob, Sophie; Cardis, Elisabeth; Wild, Pascal; Caër-Lorho, Sylvaine; Auriol, Bernard; Laurier, Dominique; Tirmarche, Margot

    2010-09-01

    This study investigated the risk of lung cancer in regards to protracted occupational exposure to reprocessed uranium compounds. Two thousand seven hundred and nine male workers employed at the AREVA NC uranium processing plant between 1960 and 2005 in France were included in the cohort. Historical exposure to reprocessed uranium compounds classified by their solubility type was assessed on the basis of the plant's specific job-exposure matrix. Cox proportional hazard models adjusted for attained age, calendar period, and socioeconomic status were used to estimate relative risks in regards of each type of uranium compound. The relative risk of lung cancer tended to increase with decreasing solubility of reprocessed uranium compounds. The highest-though not statistically significant-relative risk was observed among workers exposed to slowly soluble reprocessed uranium dioxide. This study is the first suggesting an increasing risk of lung cancer associated with exposure to reprocessed uranium. Our results are consistent with data from experimental studies of biokinetics and the action mechanism of slowly soluble uranium compounds, but need to be confirmed in larger studies with more detailed dose-response analyses. PMID:20699691

  14. Uranium sorption on various forms of titanium dioxide--influence of surface area, surface charge, and impurities.

    PubMed

    Comarmond, M Josick; Payne, Timothy E; Harrison, Jennifer J; Thiruvoth, Sangeeth; Wong, Henri K; Aughterson, Robert D; Lumpkin, Gregory R; Müller, Katharina; Foerstendorf, Harald

    2011-07-01

    Titanium dioxide (TiO(2)) has often served as a model substrate for experimental sorption studies of environmental contaminants. However, various forms of Ti-oxide have been used, and the different sorption properties of these materials have not been thoroughly studied. We investigated uranium sorption on some thoroughly characterized TiO(2) surfaces with particular attention to the influence of surface area, surface charge, and impurities. The sorption of U(VI) differed significantly between samples. Aggressive pretreatment of one material to remove impurities significantly altered the isoelectric point, determined by an electroacoustic method, but did not significantly impact U sorption. Differences in sorption properties between the various TiO(2) materials were related to the crystallographic form, morphology, surface area, and grain size, rather than to surface impurities or surface charge. In-situ attenuated total reflection Fourier-transform infrared (ATR FT-IR) spectroscopic studies showed that the spectra of the surface species of the TiO(2) samples are not significantly different, suggesting the formation of similar surface complexes. The data provide insights into the effect of different source materials and surface properties on radionuclide sorption. PMID:21618967

  15. Application of Radio-Frequency Plasma Glow Discharge to Removal of Uranium Dioxide from Metal Surfaces

    SciTech Connect

    El-Genk, Mohamed S.; Saber, Hamed H. [University of New Mexico (United States)

    2000-11-15

    Recent experiments have shown that radio-frequency (rf) plasma glow discharge using NF{sub 3} gas is an effective technique for the removal of uranium oxide from metal surfaces. The results of these experiments are analyzed to explain the measured dependence of the UO{sub 2} removal or etch rate on the NF{sub 3} gas pressure and the absorbed power in the plasma. The NF{sub 3} gas pressure in the experiments was varied from 10.8 to 40 Pa, and the deposited power in the plasma was varied from 25 to 210 W. The UO{sub 2} etch rate was strongly dependent on the absorbed power and, to a lesser extent, on the NF{sub 3} pressure and decreased exponentially with immersion time. At 210 W and 17 Pa, all detectable UO{sub 2} in the samples ({approx}10.6 mg each) was removed at the endpoint, whereas the initial etch rate was {approx}3.11 {mu}m/min. When the absorbed power was {<=}50 W, however, the etch rate was initially {approx}0.5 {mu}g/min and almost zero at the endpoint, with UO{sub 2} only partially etched. This self-limiting etching of UO{sub 2} at low power is attributed to the formation of nonvolatile intermediates UF{sub 2}, UF{sub 3}, UF{sub 4}, UF{sub 5}, UO{sub 2}F, and UO{sub 2}F{sub 2} on the surface. Analysis indicated that the accumulation of UF{sub 6} and, to a lesser extent, O{sub 2} near the surface partially contributed to the exponential decrease in the UO{sub 2} etch rate with immersion time. Unlike fluorination with F{sub 2} gas, etching of UO{sub 2} using rf glow discharge is possible below 663 K. The average etch rates of the amorphous UO{sub 2} in the NF{sub 3} experiments are comparable to the peak values reported in other studies for crystalline UO{sub 2} using CF{sub 4}/O{sub 2} glow discharge performed at {approx}150 to 250 K higher sample temperatures.

  16. Uranium resource technology, seminar 3, 1980

    Microsoft Academic Search

    1980-01-01

    This conference proceedings contains 20 papers and 1 panel discussion on uranium mining and ore treatment, taking into account the environmental issues surrounding uranium supply. Topics discussed include the U.S. uranium resource base, the technology and economics of uranium recovery from phosphate resources, trends in preleach materials handling of sandstone uranium ores, groundwater restoration after in-situ uranium leaching, mitigation of

  17. Uranium resource technology, Seminar 3, 1980

    Microsoft Academic Search

    1980-01-01

    This conference proceedings contains 20 papers and 1 panel discussion on uranium mining and ore treatment, taking into account the environmental issues surrounding uranium supply. Topics discussed include: the US uranium resource base, the technology and economics of uranium recovery from phosphate resources, trends in preleash materials handling of sandstone uranium ores, groundwater restoration after in-situ uranium leaching, mitigation of

  18. Process for electrolytically preparing uranium metal

    DOEpatents

    Haas, Paul A. (Knoxville, TN)

    1989-01-01

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

  19. Acute chemical toxicity of uranium.

    PubMed

    Kathren, Ronald L; Burklin, Richard K

    2008-02-01

    Although human experience with uranium spans more than 200 years, the LD50 for acute intake in humans has not been well established. Large acute doses of uranium can produce death from chemical toxicity in rats, guinea pigs, and other small experimental animals, with variation in sensitivity among species. However, there has never been a death attributable to uranium poisoning in humans, and humans seem to be less sensitive to both acute and chronic toxic effects of uranium than other mammalian species studied. Highly relevant data on uranium toxicity in humans are available from the experience of persons administered large doses of uranium for therapy of diabetes and from acute accidental inhalation intakes. Although the data on which to establish oral and inhalation acute LD50 for uranium in humans are sparse, they are adequate to conclude that the LD50 for oral intake of soluble uranium compounds exceeds several grams of uranium and is at least 1.0 g for inhalation intakes. For intakes of uranium compounds of lesser solubility, acute LD50 values are likely to be significantly greater. It is suggested that 5 g be provisionally considered the acute oral LD50 for uranium in humans. For inhalation intakes of soluble compounds of uranium, 1.0 g of uranium is proposed as the provisional acute inhalation LD50. PMID:18188051

  20. DIMENSIONALLY STABLE URANIUM ALLOYS. III. URANIUM-CARBON ALLOYS

    Microsoft Academic Search

    I. Sheinhartz; J. L. Zambrow

    1959-01-01

    In an attempt to improve the strength at elevated temperatures of a 1.5% ; molybdenum in uranium alloy, a network of uranium carbide was incorporated within ; the structure of the alloy by use of powder-metallurgical techniques. ; Compositions containing up to 10% uranium carbide were evaluated by the use of ; hot hardness tests at temperatures up to 700

  1. Uranium-titanium-niobium alloy

    Microsoft Academic Search

    Ludtka

    1990-01-01

    This patent describes a uranium alloy having small additions of Ti and Nb. It shows improved strength and ductility in cross-section of greater than one inch over prior uranium alloy having only Ti as an alloy element.

  2. Evaluation of a titanium dioxide-based DGT technique for measuring inorganic uranium species in fresh and marine waters.

    PubMed

    Hutchins, Colin M; Panther, Jared G; Teasdale, Peter R; Wang, Feiyue; Stewart, Ryan R; Bennett, William W; Zhao, Huijun

    2012-08-15

    A new diffusive gradients in a thin film (DGT) technique for measuring dissolved uranium (U) in freshwater is reported. The new method utilises a previously described binding phase, Metsorb (a titanium dioxide based adsorbent). This binding phase was evaluated and compared to the well-established Chelex-DGT method. Batch experiments showed quantitative uptake (100±3%) of dissolved U by Metsorb and an elution efficiency of 95% was obtained using a mixed eluent of 1 mol L(-1) NaOH/1 mol L(-1) H(2)O(2). The mass of U accumulated by Metsorb was linear (R(2)?0.98) with time across the pH range 3.0-8.1, validating the DGT measurement. The measured effective diffusion coefficients were highly dependent on pH, ranging from 2.74-4.81×10(-6)cm(2)s(-1), which were in reasonable agreement with values from the literature. Ionic strength showed no effect on the uptake of U, and thereby on diffusion coefficients, at NaNO(3) concentrations ?0.01 mol L(-1), but caused the U concentration to be underestimated by 18% and 24% at 0.1 mol L(-1) NaNO(3) and 0.7 mol L(-1) NaNO(3), respectively. Deployment of Metsorb-DGT in synthetic freshwater resulted in reliable measurement of the dissolved U concentration (C(DGT)/C(Sol)=1.05), whereas Chelex-DGT significantly underestimated the dissolved U concentration (C(DGT)/C(Sol)=0.76). Metsorb-DGT was found to give reliable results after 8h deployments in synthetic seawater but experienced competition effects with longer deployments. The Chelex-DGT was unable to measure U at all in synthetic seawater. A field deployment in a freshwater stream (Coomera River) confirmed the utility of the Metsorb-DGT method for measuring U in natural freshwaters, but performance of field deployments may require further evaluation due to the possibility of major changes in uranium speciation with pH and water composition. We recommend a filtered sample, of any water in which DGT measurements are to be made, be used to determine the appropriate diffusion coefficient under controlled laboratory conditions. PMID:22841121

  3. Uranium deposits of Brazil

    SciTech Connect

    NONE

    1991-09-01

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

  4. Pyrophoricity of uranium

    SciTech Connect

    Peacock, H.B.

    1992-03-01

    Uranium metal is pyrophoric and is capable of self-ignition in air provided conditions are favorable. Based on the data in this report, spontaneous ignition of spherical particles larger than 1/16 inch in diameter would not be expected to occur in air at room temperature (25[degree]C). The rate at which the uranium surface oxidizes in air, balanced against the rate at which the heat of reaction is lost to the surroundings, determines whether spontaneous ignition can occur. Heat loss to the surrounding environment depends on the thermal conductivity of the uranium including the oxide coating, and on the temperature gradient. The ignition temperature for uranium metal particles is a function of particle geometry, size or specific surface area, heating rate gas composition as well as the quantity and distribution of powder within a storage container. The most important variable; however, affecting the ignition temperature for single samples was found by Schnizlein and Bingle to be the specific surface area (surface area per gram) of the uranium particles. The ignition temperatures calculated from ANL data for 1/16, 1/4, and 1/2 inch diameter spherical particles are 333, 375, and 399[degree]C, respectively. The accuracy is believed to be about [plus minus]l0%, which is based on theoretical and experimental results.

  5. Pyrophoricity of uranium

    SciTech Connect

    Peacock, H.B.

    1992-03-01

    Uranium metal is pyrophoric and is capable of self-ignition in air provided conditions are favorable. Based on the data in this report, spontaneous ignition of spherical particles larger than 1/16 inch in diameter would not be expected to occur in air at room temperature (25{degree}C). The rate at which the uranium surface oxidizes in air, balanced against the rate at which the heat of reaction is lost to the surroundings, determines whether spontaneous ignition can occur. Heat loss to the surrounding environment depends on the thermal conductivity of the uranium including the oxide coating, and on the temperature gradient. The ignition temperature for uranium metal particles is a function of particle geometry, size or specific surface area, heating rate gas composition as well as the quantity and distribution of powder within a storage container. The most important variable; however, affecting the ignition temperature for single samples was found by Schnizlein and Bingle to be the specific surface area (surface area per gram) of the uranium particles. The ignition temperatures calculated from ANL data for 1/16, 1/4, and 1/2 inch diameter spherical particles are 333, 375, and 399{degree}C, respectively. The accuracy is believed to be about {plus_minus}l0%, which is based on theoretical and experimental results.

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

    E-print Network

    Boyer, Edmond

    to the pressurization of the fuel rod. Regarding the fuel integrity, a first conservative assumption is to consider of Ronchi et al. [1] reports that a plutonium dioxide sample reduced into powder during normal handling

  7. Developments in uranium in 1987

    Microsoft Academic Search

    Chenoweth

    1988-01-01

    Legal and political factors, imports, and low prices continued to plague the domestic uranium industry. As a result, the Secretary of Energy in 1987 declared the domestic industry to be nonviable for the third straight year. Uranium exploration expenditures in the US declined for the ninth consecutive year. In 1987, an estimated $18 million was spent on uranium exploration, including

  8. Corrosion-resistant uranium

    DOEpatents

    Hovis, Jr., Victor M. (Kingston, TN); Pullen, William C. (Knoxville, TN); Kollie, Thomas G. (Oak Ridge, TN); Bell, Richard T. (Knoxville, TN)

    1983-01-01

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

  9. Synthesis of uranium metal using laser-initiated reduction of uranium tetrafluoride by calcium metal

    SciTech Connect

    West, M.H.; Martinez, M.M.; Nielsen, J.B.; Court, D.C.; Appert, Q.D.

    1995-09-01

    Uranium metal has numerous uses in conventional weapons (armor penetrators) and nuclear weapons. It also has application to nuclear reactor designs utilizing metallic fuels--for example, the former Integral Fast Reactor program at Argonne National Laboratory. Uranium metal also has promise as a material of construction for spent-nuclear-fuel storage casks. A new avenue for the production of uranium metal is presented that offers several advantages over existing technology. A carbon dioxide (CO{sub 2}) laser is used to initiate the reaction between uranium tetrafluoride (UF{sub 4}) and calcium metal. The new method does not require induction heating of a closed system (a pressure vessel) nor does it utilize iodine (I{sub 2}) as a chemical booster. The results of five reductions of UF{sub 4}, spanning 100 to 200 g of uranium, are evaluated, and suggestions are made for future work in this area.

  10. THE ALLOY SYSTEMS URANIUM-TITANIUM, URANIUM-ZIRCONIUM AND URANIUM-TITANIUM- ZIRCONIUM

    Microsoft Academic Search

    B. W. Howlett; A. G. Knapton

    1959-01-01

    Dilatometric, metallographic, x-ray, and hightemperature x-ray methods ; were employed in a study of the uranium --titanium, uranium --zirconium and ; uranium --titanium --zirconium alloy systems. The three metals are mutually ; soluble in one another in their high-temperature body-centered cubic forms, and ; about 900 deg C complete solid solubility exists. There is general agreement ; between published versions

  11. High loading uranium fuel plate

    DOEpatents

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

    1990-01-01

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

  12. Fluid-bed fluoride volatility process recovers uranium from spent uranium alloy fuels

    NASA Technical Reports Server (NTRS)

    Barghusen, J. J.; Chilenskas, A. A.; Gunderson, G. E.; Holmes, J. T.; Jonke, A. A.; Kincinas, J. E.; Levitz, N. M.; Potts, G. L.; Ramaswami, D.; Stethers, H.; Turner, K. S.

    1967-01-01

    Fluid-bed fluoride volatility process recovers uranium from uranium fuels containing either zirconium or aluminum. The uranium is recovered as uranium hexafluoride. The process requires few operations in simple, compact equipment, and eliminates aqueous radioactive wastes.

  13. Uranium from seawater

    SciTech Connect

    Gregg, D.; Folkendt, M.

    1982-09-21

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

  14. Volumetric determination of the U/O ratio in uranium oxides.

    PubMed

    Engelsman, J J; Knaape, J; Visser, J

    1968-02-01

    A method is given for determining the general formula UO(2+x), of sintered uranium dioxide pellets and uranium dioxide powders. Uranium(VI) is reduced by titration with iron(II) ammonium sulphate, after which the total amount of uranium is oxidized by titration with potassium dichromate. The end-points of both titrations are detected electrometrically. Determination of x in the range 0.0001-1.00 is possible. PMID:18960276

  15. Uranium resource technology, seminar 3, 1980

    SciTech Connect

    Morse, J.G. (ed.)

    1980-01-01

    This conference proceedings contains 20 papers and 1 panel discussion on uranium mining and ore treatment, taking into account the environmental issues surrounding uranium supply. Topics discussed include the U.S. uranium resource base, the technology and economics of uranium recovery from phosphate resources, trends in preleach materials handling of sandstone uranium ores, groundwater restoration after in-situ uranium leaching, mitigation of the environmental impacts of open pit and underground uranium mining, remedial actions at inactive uranium mill tailings sites, environmental laws governing in-situ solution mining of uranium, and the economics of in-situ solution mining.

  16. Uranium resource technology, Seminar 3, 1980

    SciTech Connect

    Morse, J.G. (ed.)

    1980-01-01

    This conference proceedings contains 20 papers and 1 panel discussion on uranium mining and ore treatment, taking into account the environmental issues surrounding uranium supply. Topics discussed include: the US uranium resource base, the technology and economics of uranium recovery from phosphate resources, trends in preleash materials handling of sandstone uranium ores, groundwater restoration after in-situ uranium leaching, mitigation of the environmental impacts of open pit and underground uranium mining, remedial actions at inactive uranium mill tailings sites, environmental laws governing in-situ solution mining of uranium, and the economics of in-situ solution mining. 16 papers are indexed separately.

  17. Controlling uranium reactivity March 18, 2008

    E-print Network

    Meyer, Karsten

    March 2008 Controlling uranium reactivity March 18, 2008 Uranium is an often misunderstood metal uranium research. In reality, uranium presents a wealth of possibilities for funda- mental chemistry. Many research groups have been involved in utilizing the large size and unique reactivity of the uranium atom

  18. Method of preparation of uranium nitride

    SciTech Connect

    Kiplinger, Jaqueline Loetsch; Thomson, Robert Kenneth James

    2013-07-09

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

  19. Inhibition of uranium(VI) sorption on titanium dioxide by surface iron(III) species in ferric oxide/titanium dioxide systems.

    PubMed

    Comarmond, M Josick; Payne, Timothy E; Collins, Richard N; Palmer, Gabriel; Lumpkin, Gregory R; Angove, Michael J

    2012-10-16

    Uranium (U(VI)) sorption in systems containing titanium dioxide (TiO(2)) and various Fe(III)-oxide phases was investigated in the acidic pH range (pH 2.5-6). Studies were conducted with physical mixtures of TiO(2) and ferrihydrite, TiO(2) with coprecipitated ferrihydrite, and with systems where Fe(III) was mostly present as crystalline Fe(III) oxides. The presence of ferrihydrite resulted in decreased U(VI) sorption relative to the pure TiO(2) systems, particularly below pH 4, an unexpected result given that the presence of another sorbent would be expected to increase U(VI) uptake. In mixtures of TiO(2) and crystalline Fe(III) oxide phases, U(VI) sorption was higher than for the analogous mixtures of TiO(2) with ferrihydrite, and was similar to U(VI) sorption on TiO(2) alone. X-ray absorption spectroscopy of the TiO(2) system with freshly precipitated Fe(III) oxides indicated the presence of an Fe(III) surface phase that inhibits U(VI) sorption-a reaction whereby Fe(III) precipitates as lepidocrocite and/or ferrihydrite effectively blocking surface sorption sites on the underlying TiO(2). Competition between dissolved Fe(III) and U(VI) for sorption sites may also contribute to the observed decrease in U(VI) sorption. The present study demonstrates the complexity of sorption in mixed systems, where the oxide phases do not necessarily behave in an additive manner, and has implications for U(VI) mobility in natural and impacted environments where Fe(III) (oxyhydr)oxides are usually assumed to increase the retention of U(VI). PMID:23013221

  20. Uranium diffusion in H-451 graphite

    SciTech Connect

    Tallent, O.K.; Towns, R.L.; Wichner, R.P.

    1985-03-01

    The transport or diffusion of uranium (as a standin for plutonium) was investigated under conditions approximating those of the primary coolant loop in a high-temperature gas-cooled reactor. Profiles were obtained for uranium penetration in H-451 graphite at temperatures ranging from 900 to 1400/sup 0/C. Profile data for given temperatures were considered in terms of the following expression: (erf/sup -1/(1-C/C /SUB o/ ))/sup 2/=X/sup 2//4Dt, where C is the concentration of uranium at time t, for distance x, into the pellet; C /SUB o/ is a constant representing the uranium concentration at x = 0 for all t, and D is the diffusion coefficient. Diffusion coefficients for uranium initially present as dicarbide at 1000 and 1400/sup 0/C were found to be defined by Duc/sub 2/ = 3.5 X 10/sup -3/ exp(-4.8 X 10/sup 4//RT) cm/sup 2//s. For uranium initially present as dioxide at 900, 1000, and 1400/sup 0/C, diffusion coefficients are defined by Duo/sub 2/ = 2.34 X 10/sup -6/ exp(-3.2 X 10/sup 4//RT) cm/sup 2//s, where R is the gas constant and T is the temperature in degrees Kelvin.

  1. Uranium transfer around volcanic-associated uranium deposit

    Microsoft Academic Search

    Vladislav A. Petrov; Antje Wittenberg; Ulrich Schwarz-Schampera; Jörg Hammer

    \\u000a Only about 60% of the annual consumption in the nuclear fuel cycle is provided by primary uranium production at present. Hence,\\u000a a strong demand for additional exploration of additional uranium resources is identified in many countries. Hence, a large\\u000a potential exists for unconventional uranium deposits such as mobilization areas in the surroundings of known deposits. Besides\\u000a environmental aspects a deep

  2. Control of uranium hazards - Portsmouth uranium enrichment plant

    SciTech Connect

    Wagner, E.R.

    1985-11-01

    This report summarizes the Environmental, Safety and Health programs to control uranium hazards at the Portsmouth Gaseous Diffusion Plant. A description of the physical plant, the facility processes and the attendant uranium flows and effluents are provided. The hazards of uranium are discussed and the control systems are outlined. Finally, the monitoring programs are described and summaries of recent data are provided. 11 figs., 20 tabs.

  3. Method for fabricating uranium foils and uranium alloy foils

    DOEpatents

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

    2006-09-05

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

  4. Uranium price forecasting methods

    SciTech Connect

    Fuller, D.M.

    1994-03-01

    This article reviews a number of forecasting methods that have been applied to uranium prices and compares their relative strengths and weaknesses. The methods reviewed are: (1) judgemental methods, (2) technical analysis, (3) time-series methods, (4) fundamental analysis, and (5) econometric methods. Historically, none of these methods has performed very well, but a well-thought-out model is still useful as a basis from which to adjust to new circumstances and try again.

  5. Uranium in prehistoric Indian pottery 

    E-print Network

    Filberth, Ernest William

    1976-01-01

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

  6. NEWS AND INFORMATION: Depleted uranium

    Microsoft Academic Search

    Richard Wakeford

    2001-01-01

    The potential health effects arising from exposure to depleted uranium have been much in the news of late. Naturally occurring uranium contains the radioisotopes 238U (which dominates, at a current molar proportion of 99.3%), 235U and a small amount of 234U. Depleted uranium has an isotopic concentration of 235U that is below the 0.7% found naturally. This is either because

  7. Uranium Critical Point Location Problem

    E-print Network

    Iosilevskiy, Igor

    2013-01-01

    Significant uncertainty of our present knowledge for uranium critical point parameters is under consideration. Present paper is devoted to comparative analysis of possible resolutions for the problem of uranium critical point location, as well as to discussion of plausible scheme of decisive experiment, which could resolve existing uncertainty. New calculations of gas-liquid coexistence in uranium by modern thermodynamic code are included in the analysis.

  8. Uranium geology of Bulgaria

    SciTech Connect

    Not Available

    1993-02-01

    Three major uranium districts containing several deposits, plus 32 additional deposits, have been identified in Bulgaria, all of which are detailed geologically in this article. Most of the deposits are located in the West Balkan mountains, the western Rhodope mountains, and the Thracian Basin. A few deposits occur in the East Balkan, eastern Rhodope and Sredna Gora mountains. The types of deposits are sandstone, vein, volcanic, and surficial. Sandstone deposits are hosted in Permian and Tertiary sediments. In early 1992, fifteen deposits were being exploited, of which roughly 70 percent of the uranium produced was being recovered using in-situ leaching (ISL) methods. The remainder was being recovered by conventional underground mining, except for one small deposit that utilized open-pit methods. Fifteen other Bulgarian deposits had been exhausted, while five deposits were still in the exploration stage. Uranium production began in Bulgaria in 1946, and cumulative production through 1991 exceeded 100 million pounds equivalent U3O8. Current annual production is on the order of one million pounds equivalent U3O8, about 750 thousand pounds of which are recovered by ISL operations.

  9. Sputtering of uranium

    NASA Technical Reports Server (NTRS)

    Gregg, R.; Tombrello, T. A.

    1978-01-01

    Results are presented for an experimental study of the sputtering of U-235 atoms from foil targets by hydrogen, helium, and argon ions, which was performed by observing tracks produced in mica by fission fragments following thermal-neutron-induced fission. The technique used allowed measurements of uranium sputtering yields of less than 0.0001 atom/ion as well as yields involving the removal of less than 0.01 monolayer of the uranium target surface. The results reported include measurements of the sputtering yields for 40-120-keV protons, 40-120-keV He-4(+) ions, and 40- and 80-keV Ar-40(+) ions, the mass distribution of chunks emitted during sputtering by the protons and 80-keV Ar-40(+) ions, the total chunk yield during He-4(+) sputtering, and some limited data on molecular sputtering by H2(+) and H3(+). The angular distribution of the sputtered uranium is discussed, and the yields obtained are compared with the predictions of collision cascade theory.

  10. The toxicity of depleted uranium.

    PubMed

    Briner, Wayne

    2010-01-01

    Depleted uranium (DU) is an emerging environmental pollutant that is introduced into the environment primarily by military activity. While depleted uranium is less radioactive than natural uranium, it still retains all the chemical toxicity associated with the original element. In large doses the kidney is the target organ for the acute chemical toxicity of this metal, producing potentially lethal tubular necrosis. In contrast, chronic low dose exposure to depleted uranium may not produce a clear and defined set of symptoms. Chronic low-dose, or subacute, exposure to depleted uranium alters the appearance of milestones in developing organisms. Adult animals that were exposed to depleted uranium during development display persistent alterations in behavior, even after cessation of depleted uranium exposure. Adult animals exposed to depleted uranium demonstrate altered behaviors and a variety of alterations to brain chemistry. Despite its reduced level of radioactivity evidence continues to accumulate that depleted uranium, if ingested, may pose a radiologic hazard. The current state of knowledge concerning DU is discussed. PMID:20195447

  11. Uranium droplet core nuclear rocket

    NASA Technical Reports Server (NTRS)

    Anghaie, Samim

    1991-01-01

    Uranium droplet nuclear rocket is conceptually designed to utilize the broad temperature range ofthe liquid phase of metallic uranium in droplet configuration which maximizes the energy transfer area per unit fuel volume. In a baseline system dissociated hydrogen at 100 bar is heated to 6000 K, providing 2000 second of Isp. Fission fragments and intense radian field enhance the dissociation of molecular hydrogen beyond the equilibrium thermodynamic level. Uranium droplets in the core are confined and separated by an axisymmetric vortex flow generated by high velocity tangential injection of hydrogen in the mid-core regions. Droplet uranium flow to the core is controlled and adjusted by a twin flow nozzle injection system.

  12. The Toxicity of Depleted Uranium

    PubMed Central

    Briner, Wayne

    2010-01-01

    Depleted uranium (DU) is an emerging environmental pollutant that is introduced into the environment primarily by military activity. While depleted uranium is less radioactive than natural uranium, it still retains all the chemical toxicity associated with the original element. In large doses the kidney is the target organ for the acute chemical toxicity of this metal, producing potentially lethal tubular necrosis. In contrast, chronic low dose exposure to depleted uranium may not produce a clear and defined set of symptoms. Chronic low-dose, or subacute, exposure to depleted uranium alters the appearance of milestones in developing organisms. Adult animals that were exposed to depleted uranium during development display persistent alterations in behavior, even after cessation of depleted uranium exposure. Adult animals exposed to depleted uranium demonstrate altered behaviors and a variety of alterations to brain chemistry. Despite its reduced level of radioactivity evidence continues to accumulate that depleted uranium, if ingested, may pose a radiologic hazard. The current state of knowledge concerning DU is discussed. PMID:20195447

  13. Oxidation states of uranium in depleted uranium particles from Kuwait

    Microsoft Academic Search

    B. Salbu; K. Janssens; O. C. Lind; K. Proost; L. Gijsels; P. R. Danesi

    2004-01-01

    The oxidation states of uranium in depleted uranium (DU) particles were determined by synchrotron radiation based ?-XANES, applied to individual particles isolated from selected samples collected at different sites in Kuwait. Based on scanning electron microscopy with X-ray microanalysis prior to ?-XANES, DU particles ranging from submicrons to several hundred micrometers were observed. The median particle size depended on sources

  14. 31 CFR 540.317 - Uranium feed; natural uranium feed.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    31 ? Money and Finance:Treasury ? 3 ? 2012-07-01 ? 2012-07-01 ? false ? Uranium feed; natural uranium feed. ? 540.317 ? Section 540.317 ? Money and Finance: Treasury ? Regulations Relating to Money and Finance (Continued) ? OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ?...

  15. 31 CFR 540.317 - Uranium feed; natural uranium feed.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    31 ? Money and Finance:Treasury ? 3 ? 2014-07-01 ? 2014-07-01 ? false ? Uranium feed; natural uranium feed. ? 540.317 ? Section 540.317 ? Money and Finance: Treasury ? Regulations Relating to Money and Finance (Continued) ? OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ?...

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

    DOEpatents

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

    2001-01-01

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

  17. 31 CFR 540.317 - Uranium feed; natural uranium feed.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    31 ? Money and Finance:Treasury ? 3 ? 2011-07-01 ? 2011-07-01 ? false ? Uranium feed; natural uranium feed. ? 540.317 ? Section 540.317 ? Money and Finance: Treasury ? Regulations Relating to Money and Finance (Continued) ? OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ?...

  18. 31 CFR 540.317 - Uranium feed; natural uranium feed.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    31 ? Money and Finance:Treasury ? 3 ? 2013-07-01 ? 2013-07-01 ? false ? Uranium feed; natural uranium feed. ? 540.317 ? Section 540.317 ? Money and Finance: Treasury ? Regulations Relating to Money and Finance (Continued) ? OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ?...

  19. 31 CFR 540.317 - Uranium feed; natural uranium feed.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    31 ? Money and Finance: Treasury ? 3 ? 2010-07-01 ? 2010-07-01 ? false ? Uranium feed; natural uranium feed. ? 540.317 ? Section 540.317 ? Money and Finance: Treasury ? Regulations Relating to Money and Finance (Continued) ? OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ?...

  20. Method for fluorination of uranium oxide

    DOEpatents

    Petit, George S. (Oak Ridge, TN)

    1987-01-01

    Highly pure uranium hexafluoride is made from uranium oxide and fluorine. The uranium oxide, which includes UO.sub.3, UO.sub.2, U.sub.3 O.sub.8 and mixtures thereof, is introduced together with a small amount of a fluorine-reactive substance, selected from alkali chlorides, silicon dioxide, silicic acid, ferric oxide, and bromine, into a constant volume reaction zone. Sufficient fluorine is charged into the zone at a temperature below approximately 0.degree. C. to provide an initial pressure of at least approximately 600 lbs/sq. in. at the ambient atmospheric temperature. The temperature is then allowed to rise in the reaction zone until reaction occurs.

  1. PLUTONIUM-URANIUM-TITANIUM ALLOYS

    Microsoft Academic Search

    Coffinberry

    1959-01-01

    A plutonium-uranium alloy suitable for use as the fuel element in a fast ; breeder reactor is described. The alloy contains from 15 to 60 at.% titanium ; with the remainder uranium and plutonium in a specific ratio, thereby limiting ; the undesirable zeta phase and rendering the alloy relatively resistant to ; corrosion and giving it the essential characteristic

  2. Developments in uranium in 1987

    SciTech Connect

    Chenoweth, W.L.

    1988-10-01

    Legal and political factors, imports, and low prices continued to plague the domestic uranium industry. As a result, the Secretary of Energy in 1987 declared the domestic industry to be nonviable for the third straight year. Uranium exploration expenditures in the US declined for the ninth consecutive year. In 1987, an estimated $18 million was spent on uranium exploration, including 1.9 million ft of surface drilling. This drilling was done mainly in production areas and in areas of recent discoveries. Production of uranium concentrate decreased slightly in 1987, when 12.5 million lb of uranium oxide (U/sub 3/O/sub 8/) were produced, a 7% decrease from 1986. Uranium produced from mine water, solution mining, and as the byproduct of phosphoric acid and copper production accounted for about 38% of the total production in the US. At the end of 1987, only 5 uranium mills were operating in the US. The large, high-grade reserves being discovered and developed in Saskatchewan will enable Canada to dominate the world market for many years. Development of the Olympic Dam deposit continued in Australia and will being production in 1988. US uranium production is expected to increase slightly in 1988, as a new open-pit mine begin production. 3 figs., 2 tabs.

  3. The ? Phase in Uranium Alloys

    Microsoft Academic Search

    R G Loasby

    1958-01-01

    Electrical resistivity and magnetic susceptibility properties of two alloys based on ?-uranium are described and interpreted in terms of a theoretical structure derived from X-ray work by P. C. L. Pfeil. The implication of the earlier work, that uranium in the ? form is characterized by only four electrons per atom (as opposed to six for the ? and ?

  4. Compensation of Navajo Uranium Miners

    NSDL National Science Digital Library

    World Information Service on Energy Uranium Project

    This site addresses policy issues of the compensation of Navajo uranium miners. The site provides an annotated index of current issues, legislation, papers and presentations, books, and links that lead to more information on uranium miners. Imbedded links throughout the text lead to related information.

  5. Uranium in foraminiferal calcite as a recorder of seawater uranium concentrations

    Microsoft Academic Search

    A. D. Russell; S. Emerson; B. K. Nelson; J. Erez; D. W. Lea

    1994-01-01

    The authors present results of an investigation of uranium\\/calcium ratios in cleaned foraminiferal calcite as a recorder of seawater uranium concentrations. For accurate reconstruction of past seawater uranium content, shell calcite must incorporate uranium in proportion to seawater concentration and must preserve its original uranium composition over time. Laboratory culture experiments with live benthic (Amphistegina lobifera) and live planktonic (Globigerinell

  6. EXAMINATION AND PROPERTIES OF URANIUM ALLOYS

    Microsoft Academic Search

    H. A. Saller; F. A. Rough

    1953-01-01

    The heat treatment, microstructure, hardness, and density data for a ; series of uranium alloys are described. These are alloys which were studied ; because of their potential interest for high-temperature water-corrosion ; resistance. The alloys studied include uranium--zirconium biiiary alloys, ; uranium-- zirconium-base ternary alloys, and uranium --molybdenum alloys. ; (auth);

  7. Uranium and plutonium isotopes in the atmosphere

    Microsoft Academic Search

    Y. Sakuragi; J. L. Meason; P. K. Kuroda

    1983-01-01

    Uranium 234 and 235 were found to be highly enriched relative to uranium 238 in several rain samples collected at Fayetteville, Arkansas, during the months of April and May 1980. The anomalous uranium appears to have originated from the Soviet satellite Cosmos-954, which fell over Canada on January 24, 1978. The uranium fallout occurred just about the time Mount St.

  8. Uranium accumulation by Pseudomonas sp. EPS5028

    Microsoft Academic Search

    Ana M. Marqués; Xavier Roca; M. Dolores Simon-Pujol; M. Carmen Fuste; Francisco Congregado

    1991-01-01

    Pseudomonas sp. EPS-5028 was examined for the ability to accumulate uranium from solutions. The uptake of uranium by this microorganism is very rapid and is affected by pH but not by temperature, metabolic inhibitors, culture time and the presence of various cations and anions. The amount of uranium absorbed by the cells increased as the uranium concentration of the solution

  9. APPENDIX J Partition Coefficients For Uranium

    E-print Network

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

  10. The End of Cheap Uranium

    E-print Network

    Michael Dittmar

    2011-06-21

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

  11. Determination of uranium in zircon

    USGS Publications Warehouse

    Cuttitta, F.; Daniels, G.J.

    1959-01-01

    A routine fluorimetric procedure is described for the determination of trace amounts of uranium in zircon. It employs the direct extraction of uranyl nitrate with ethyl acetate using phosphate as a retainer for zirconium. Submicrogram amounts or uranium are separated in the presence of 100,000 times the amount of zirconium. The modified procedure has been worked out using synthetic mixtures of known composition and zircon. Results of analyses have an accuracy of 97-98% of the contained uranium and a standard deviation of less than 2.5%. ?? 1959.

  12. Effects of uranium ore dust on cultured human lung cells.

    PubMed

    Ohshima, S; Xu, Y; Takahama, M

    1998-06-01

    Effects of uranium ore dust on cell proliferation, lipid peroxidation and micronuclei formation were compared with silica (DQ12) and titanium oxide in normal human distal airway epithelial cells (NHDE), human lung cancer cells (A549) and human lung fibroblast cells. Cell proliferation was significantly inhibited with uranium ore dust and silica but not with titanium oxide. Lipid peroxidation was significantly enhanced only with uranium ore dust. Micronuclei formation was significantly stimulated with uranium ore dust in A549 and NHDE cells, but not in fibroblast cells. Silica stimulated micronuclei formation only in A549 cells. The results showed the outstanding effect of uranium ore dust on lipid peroxidation and micronuclei formation in human lung cells compared to silica and titanium dioxide. PMID:21781873

  13. The Core: Uranium Institute

    NSDL National Science Digital Library

    The Uranium Institute (UI) is an international organization comprised of members who are involved in all "stages of the production of nuclear generated electricity" in the hopes of promoting the use of nuclear energy to supply energy demands, while minimizing environmental risks. The goals of the Institute are to monitor the outlook for the world's nuclear fuel markets, provide a forum between the nuclear fuel industry and the international organizations concerned with environmental issues as well as energy policy, and to make the public gain a general understanding of the nuclear fuel cycle. Sections are divided into three categories: Features, the UI, and the Industry. Although the site is somewhat news-oriented, it informs users about industries involved with nuclear-generated electricity and how they manage radioactive waste.

  14. ELECTROCHEMICAL STUDIES OF URANIUM METAL CORROSION MECHANISM AND KINETICS IN WATER

    SciTech Connect

    Boudanova, Natalya; Maslennikov, Alexander; Peretroukhine, Vladimir F.; Delegard, Calvin H.

    2006-10-01

    During long-term underwater storage of low burn-up uranium metal fuel, a corrosion product sludge forms containing uranium metal grains1, uranium dioxide1,2, uranates1 and, in some cases, uranium peroxide1,3. Literature data on the corrosion of non-irradiated uranium metal and its alloys2,4 do not allow unequivocal prediction of the paragenesis of irradiated uranium in water. The goal of the present work conducted under the program «CORROSION OF IRRADIATED URANIUM ALLOYS FUEL IN WATER» is to study the corrosion of uranium and uranium alloys and the paragenesis of the corrosion products during long-term underwater storage of uranium alloy fuel irradiated at the Hanford Site. The elucidation of the physico-chemical nature of the corrosion of irradiated uranium alloys in comparison with non-irradiated uranium metal and its alloys is one of the most important aspects of this work. Electrochemical methods are being used to study uranium metal corrosion mechanism and kinetics. The present part of work aims to examine and revise, where appropriate, the understanding of uranium metal corrosion mechanism and kinetics in water.

  15. Laser induced phosphorescence uranium analysis

    DOEpatents

    Bushaw, Bruce A. (Kennewick, WA)

    1986-01-01

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

  16. Laser induced phosphorescence uranium analysis

    DOEpatents

    Bushaw, B.A.

    1983-06-10

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

  17. Rescuing a Treasure Uranium-233

    SciTech Connect

    Krichinsky, Alan M [ORNL] [ORNL; Goldberg, Dr. Steven A. [DOE SC - Chicago Office] [DOE SC - Chicago Office; Hutcheon, Dr. Ian D. [Lawrence Livermore National Laboratory (LLNL)] [Lawrence Livermore National Laboratory (LLNL)

    2011-01-01

    Uranium-233 (233U) is a synthetic isotope of uranium formed under reactor conditions during neutron capture by natural thorium (232Th). At high purities, this synthetic isotope serves as a crucial reference for accurately quantifying and characterizing natural uranium isotopes for domestic and international safeguards. Separated 233U is stored in vaults at Oak Ridge National Laboratory. These materials represent a broad spectrum of 233U from the standpoint isotopic purity the purest being crucial for precise analyses in safeguarding uranium. All 233U at ORNL currently is scheduled to be down blended with depleted uranium beginning in 2015. Such down blending will permanently destroy the potential value of pure 233U samples as certified reference material for use in uranium analyses. Furthermore, no replacement 233U stocks are expected to be produced in the future due to a lack of operating production capability and the high cost of returning to operation this currently shut down capability. This paper will describe the efforts to rescue the purest of the 233U materials arguably national treasures from their destruction by down blending.

  18. Mortality among uranium enrichment workers

    SciTech Connect

    Brown, D.P.; Bloom, T.

    1987-01-01

    A retrospective cohort mortality study was conducted on workers at the Portsmouth Uranium Enrichment facility in Pike County, Ohio, in response to a request from the Oil, Chemical and Atomic Workers International Local 3-689 for information on long-term health effects. Primary hazards included inhalation exposure to uranyl fluoride containing uranium-235 and uranium-234, technetium-99 compounds, and hydrogen-fluoride. Uranium-238 presented a nephrotoxic hazard. Statistically significant mortality deficits based on U.S. death rates were found for all causes, accidents, violence, and diseases of nervous, circulatory, respiratory, and digestive systems. Standardized mortality rates were 85 and 54 for all malignant neoplasms and for other genitourinary diseases, respectively. Deaths from stomach cancer and lymphatic/hematopoietic cancers were insignificantly increased. A subcohort selected for greatest potential uranium exposure has reduced deaths from these malignancies. Insignificantly increased stomach cancer mortality was found after 15 years employment and after 15 years latency. Routine urinalysis data suggested low internal uranium exposures.

  19. Process for alloying uranium and niobium

    SciTech Connect

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

    1990-12-31

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

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

    E-print Network

    Helmreich, Grant

    2012-02-14

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

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

    E-print Network

    Helmreich, Grant

    2012-02-14

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

  2. The end of cheap uranium.

    PubMed

    Dittmar, Michael

    2013-09-01

    Historic data from many countries demonstrate that on average no more than 50-70% of the uranium in a deposit could be mined. An analysis of more recent data from Canada and Australia leads to a mining model with an average deposit extraction lifetime of 10±2 years. This simple model provides an accurate description of the extractable amount of uranium for the recent mining operations. Using this model for all larger existing and planned uranium mines up to 2030, a global uranium mining peak of at most 58±4 ktons around the year 2015 is obtained. Thereafter we predict that uranium mine production will decline to at most 54±5 ktons by 2025 and, with the decline steepening, to at most 41±5 ktons around 2030. This amount will not be sufficient to fuel the existing and planned nuclear power plants during the next 10-20 years. In fact, we find that it will be difficult to avoid supply shortages even under a slow 1%/year worldwide nuclear energy phase-out scenario up to 2025. We thus suggest that a worldwide nuclear energy phase-out is in order. If such a slow global phase-out is not voluntarily effected, the end of the present cheap uranium supply situation will be unavoidable. The result will be that some countries will simply be unable to afford sufficient uranium fuel at that point, which implies involuntary and perhaps chaotic nuclear phase-outs in those countries involving brownouts, blackouts, and worse. PMID:23683936

  3. Uranium Oxide Aerosol Transport in Porous Graphite

    SciTech Connect

    Blanchard, Jeremy; Gerlach, David C.; Scheele, Randall D.; Stewart, Mark L.; Reid, Bruce D.; Gauglitz, Phillip A.; Bagaasen, Larry M.; Brown, Charles C.; Iovin, Cristian; Delegard, Calvin H.; Zelenyuk, Alla; Buck, Edgar C.; Riley, Brian J.; Burns, Carolyn A.

    2012-01-23

    The objective of this paper is to investigate the transport of uranium oxide particles that may be present in carbon dioxide (CO2) gas coolant, into the graphite blocks of gas-cooled, graphite moderated reactors. The transport of uranium oxide in the coolant system, and subsequent deposition of this material in the graphite, of such reactors is of interest because it has the potential to influence the application of the Graphite Isotope Ratio Method (GIRM). The GIRM is a technology that has been developed to validate the declared operation of graphite moderated reactors. GIRM exploits isotopic ratio changes that occur in the impurity elements present in the graphite to infer cumulative exposure and hence the reactor’s lifetime cumulative plutonium production. Reference Gesh, et. al., for a more complete discussion on the GIRM technology.

  4. Uranium reference materials

    SciTech Connect

    Donivan, S.; Chessmore, R.

    1987-07-01

    The Technical Measurements Center has prepared uranium mill tailings reference materials for use by remedial action contractors and cognizant federal and state agencies. Four materials were prepared with varying concentrations of radionuclides, using three tailings materials and a river-bottom soil diluent. All materials were ground, dried, and blended thoroughly to ensure homogeneity. The analyses on which the recommended values for nuclides in the reference materials are based were performed, using independent methods, by the UNC Geotech (UNC) Chemistry Laboratory, Grand Junction, Colorado, and by C.W. Sill (Sill), Idaho National Engineering Laboratory, Idaho Falls, Idaho. Several statistical tests were performed on the analytical data to characterize the reference materials. Results of these tests reveal that the four reference materials are homogeneous and that no large systematic bias exists between the analytical methods used by Sill and those used by TMC. The average values for radionuclides of the two data sets, representing an unbiased estimate, were used as the recommended values for concentrations of nuclides in the reference materials. The recommended concentrations of radionuclides in the four reference materials are provided. Use of these reference materials will aid in providing uniform standardization among measurements made by remedial action contractors. 11 refs., 9 tabs.

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

    E-print Network

    Meyer, Karsten

    Uranium Tris-aryloxide Derivatives Supported by Triazacyclononane: Engendering a Reactive Uranium-mail: kmeyer@ucsd.edu Abstract: The synthesis and spectroscopic characterization of the mononuclear uranium complex [((ArO)3tacn)UIII (NCCH3)] is reported. The uranium(III) complex reacts with organic azides

  6. Evidence of uranium biomineralization in sandstone-hosted roll-front uranium deposits, northwestern China

    E-print Network

    Fayek, Mostafa

    Evidence of uranium biomineralization in sandstone-hosted roll-front uranium deposits, northwestern Available online 25 January 2005 Abstract We show evidence that the primary uranium minerals, uraninite-front uranium deposits, Xinjiang, northwestern China were biogenically precipitated and psuedomorphically

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

    E-print Network

    Boyer, Edmond

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

  8. POTENTIAL TOXICITY OF URANIUM IN WATER

    EPA Science Inventory

    The nephrotoxic responses of mammalian species, including humans, to injected, inhaled, ingested, and topically applied uranium compounds have been thoroughly investigated. Because there appears to be on unequivocal reports of uranium-induced radiation effects in humans, it is ne...

  9. Reducing emissions from uranium dissolving

    SciTech Connect

    Griffith, W.L.; Compere, A.L.; Huxtable, W.P.; Googin, J.M.

    1992-10-01

    This study was designed to assess the feasibility of decreasing NO{sub x} emissions from the current uranium alloy scrap tray dissolving facility. In the current process, uranium scrap is dissolved in boiling nitric acid in shallow stainless-steel trays. As scrap dissolves, more metal and more nitric acid are added to the tray by operating personnel. Safe geometry is assured by keeping liquid level at or below 5 cm, the depth of a safe infinite slab. The accountability batch control system provides additional protection against criticality. Both uranium and uranium alloys are dissolved. Nitric acid is recovered from the vapors for reuse. Metal nitrates are sent to uranium recovery. Brown NO{sub x} fumes evolved during dissolving have occasionally resulted in a visible plume from the trays. The fuming is most noticeable during startup and after addition of fresh acid to a tray. Present environmental regulations are expected to require control of brown NO{sub x} emissions. A detailed review of the literature, indicated the feasibility of slightly altering process chemistry to favor the production of NO{sub 2} which can be scrubbed and recycled as nitric acid. Methods for controlling the process to manage offgas product distribution and to minimize chemical reaction hazards were also considered.

  10. Reducing emissions from uranium dissolving

    SciTech Connect

    Griffith, W.L.; Compere, A.L.; Huxtable, W.P.; Googin, J.M.

    1992-10-01

    This study was designed to assess the feasibility of decreasing NO[sub x] emissions from the current uranium alloy scrap tray dissolving facility. In the current process, uranium scrap is dissolved in boiling nitric acid in shallow stainless-steel trays. As scrap dissolves, more metal and more nitric acid are added to the tray by operating personnel. Safe geometry is assured by keeping liquid level at or below 5 cm, the depth of a safe infinite slab. The accountability batch control system provides additional protection against criticality. Both uranium and uranium alloys are dissolved. Nitric acid is recovered from the vapors for reuse. Metal nitrates are sent to uranium recovery. Brown NO[sub x] fumes evolved during dissolving have occasionally resulted in a visible plume from the trays. The fuming is most noticeable during startup and after addition of fresh acid to a tray. Present environmental regulations are expected to require control of brown NO[sub x] emissions. A detailed review of the literature, indicated the feasibility of slightly altering process chemistry to favor the production of NO[sub 2] which can be scrubbed and recycled as nitric acid. Methods for controlling the process to manage offgas product distribution and to minimize chemical reaction hazards were also considered.

  11. Uranium in the Monterey Formation of California

    SciTech Connect

    Durham, D.L.

    1987-01-01

    Diagenesis that accompanied burial of the diatomaceous Monterey Formation produced diatomite, porcelanite, and chart containing uranium in amounts ranging from less than 2 to more than 1,850 parts per million. Most of the uranium is associated with organic material.The Monterey Formation is a potential large-volume, low-grade uranium source and is a potential source of secondary uranium for sandstone-type deposits.

  12. Dissolution of metallic uranium and its alloys

    Microsoft Academic Search

    C. A. Laue; D. Gates-Anderson; T. E. Fitch

    2004-01-01

    This review focuses on dissolution\\/reaction systems capable of treating uranium metal waste to remove its pyrophoric properties.\\u000a The primary emphasis is the review of literature describing analytical and production-scale dissolution methods applied to\\u000a either uranium metal or uranium alloys. A brief summary of uranium's corrosion behavior is included since the corrosion resistance\\u000a of metals and alloys affects their dissolution behavior.

  13. Geochemical coupling of uranium and phosphorous in soils overlying an unmined uranium deposit: Coles Hill, Virginia

    Microsoft Academic Search

    James L. Jerden; A. K. Sinha

    2006-01-01

    The mineralogy and geochemistry of soils developed over the unmined Coles Hill uranium deposit (Virginia) were studied to determine how phosphorous influences the speciation of uranium in oxidizing soil\\/saprolite systems typical of the eastern US. Results from this study have implications for both uranium remediation (e.g. in situ stabilization) and uranium resource exploration (e.g. near-surface geochemical sampling). The primary uranium

  14. Preserving Ultra-Pure Uranium233

    Microsoft Academic Search

    Alan M Krichinsky; Steven A. Goldberg; Ian D. Hutcheon

    2011-01-01

    Uranium-233 (²³³U) is a synthetic isotope of uranium formed under reactor conditions during neutron capture by natural thorium (²³²Th). At high purities, this synthetic isotope serves as a crucial reference material for accurately quantifying and characterizing uranium-bearing materials assays and isotopic distributions for domestic and international nuclear safeguards. Separated, high purity ²³³U is stored in vaults at Oak Ridge National

  15. Medical effects of internal contamination with uranium.

    PubMed

    Durakovi?, A

    1999-03-01

    The purpose of this work is to present an outline of the metabolic pathways of uranium isotopes and compounds, medical consequences of uranium poisoning, and an evaluation of the therapeutic alternatives in uranium internal contamination. The chemical toxicity of uranium has been recognized for more than two centuries. Animal experiments and human studies are conclusive about metabolic adverse affects and nephro- toxicity of uranium compounds. Radiation toxicity of uranium isotopes has been recognized since the beginning of the nuclear era, with well documented evidence of reproductive and developmental toxicity, as well as mutagenic and carcinogenic consequences of uranium internal contamination. Natural uranium (238U), an alpha emitter with a half-life of 4.5x10(9) years, is one of the primordial substances of the universe. It is found in the earth's crust, combined with 235U and 234U, alpha, beta, and gamma emitters with respective half-lives of 7.1x10(8) and 2.5x10(5) years. A special emphasis of this paper concerns depleted uranium. The legacy of radioactive waste, environmental and health hazards in the nuclear industry, and, more recently, the military use of depleted uranium in the tactical battlefield necessitates further insight into the toxicology of depleted uranium. The present controversy over the radiological and chemical toxicity of depleted uranium used in the Gulf War warrants further experimental and clinical investigations of its effects on the biosphere and human organisms. PMID:9933897

  16. Renal Effects of Uranium in Drinking Water

    Microsoft Academic Search

    Päivi Kurttio; Anssi Auvinen; Laina Salonen; Heikki Saha; Juha Pekkanen; Ilona Mäkeläinen; Sari B. Väisänen; Ilkka M. Penttilä; Hannu Komulainen

    2002-01-01

    statistically significantly associated with calcium fractional excretion, but not with phosphate or glucose excretion. Uranium exposure was not associated with creatinine clearance or urinary albu- min, which reflect glomerular function. In conclusion, uranium exposure is weakly associated with altered proximal tubulus function without a clear threshold, which suggests that even low uranium concentrations in drinking water can cause nephrotoxic effects.

  17. SHEEP MOUNTAIN URANIUM PROJECT CROOKS GAP, WYOMING

    E-print Network

    and Open Pit Mining ·Current Mine Permit (381C) ·Updating POO, Reclamation Plan & Bond ·Uranium Recovery;PROJECT OVERVIEW ·Site Location·Site Location ·Fremont , Wyoming ·Existing Uranium Mine Permit 381C·Existing Uranium Mine Permit 381C ·Historical Operation ·Western Nuclear Crooks Gap Project ·Mined 1956 ­ 1988

  18. VOLUMETRIC DETERMINATION OF THORIUM IN URANIUM ALLOYS

    Microsoft Academic Search

    H. H. Willard; A. W. Mosen; R. D. Gardner

    1958-01-01

    Thorium is determined in uranium- thoriura, uranium--tungsten-thorium, ; and uranium -- titanium-thorium alloys by precipitation as the fluoride, using ; lanthanum as a carrier, followed by titration with EDTA. Eriochrome Cyanine RC ; is used as the indicator in the titration. ln 161 determinations of known ; solutions simulating the alloys with a thorium content of 0.1 to 3.0%, an

  19. URANIUM MILL TAILINGS RADON FLUX CALCULATIONS

    E-print Network

    URANIUM MILL TAILINGS RADON FLUX CALCULATIONS PIÑON RIDGE PROJECT MONTROSE COUNTY, COLORADO (EFRC) proposes to license, construct, and operate a conventional acid leach uranium and vanadium mill storage pad, and access roads. The mill is designed to process ore containing uranium and vanadium

  20. High strength uranium-tungsten alloys

    DOEpatents

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

    1991-01-01

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

  1. Recovery of uranium by immobilized microorganisms

    Microsoft Academic Search

    Akira Nakajima; Takao Horikoshi; Takashi Sakaguchi

    1982-01-01

    Some attempts were made to recover uranium from sea and fresh water using immobilized Streptomyces viridochromogenes and Chlorella regularis cells. The cells immobilized in polyacrylamide gel have the most favorable features for uranium recovery; high adsorption ability, good mechanical properties, and applicability in a column system. The adsorption of uranium by the immobilized cells is not affected by the pH

  2. Uranium Watch REGULATORY CONFUSION: FEDERALAND STATE

    E-print Network

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

  3. Safe Operating Procedure SAFETY PROTOCOL: URANIUM

    E-print Network

    Farritor, Shane

    Safe Operating Procedure (5/09) SAFETY PROTOCOL: URANIUM be approved by the RSC. Physical Data Physical data for isotopes of uranium and primary decay products are provided in the following table. Table 1. Physical Properties of Uranium Isotopes. Isotope Half

  4. High strength uranium-tungsten alloy process

    DOEpatents

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

    1990-01-01

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

  5. D Riso-R-429 Automated Uranium

    E-print Network

    CM i D Riso-R-429 Automated Uranium Analysis by Delayed-Neutron Counting H. Kunzendorf, L. Løvborg AUTOMATED URANIUM ANALYSIS BY DELAYED-NEUTRON COUNTING H. Kunzendorf, L. Løvborg and E.M. Christiansen Electronics Department Abstract. Automated uranium analysis by fission-induced delayed- neutron counting

  6. Summary of an interlaboratory comparison program on the analysis of pyrocarbon- and silicon carbide-coated uranium--thorium carbide beads

    Microsoft Academic Search

    C. D. Bingham; J. Whichard

    1973-01-01

    Annual progress report for the period July 1972 through June NBL ; conducted an interlaboratory comparison program on the analysis of pyrocarbon- ; and silicon carbide-coated uranium-thorium carbide nuclear fuel beads. Samples ; of the beads from a single production lot, and synthetic uranium dioxide-- ; thorium dioxide mixtures were analyzed for uranium by 3 laboratories by ; nondestructive assay

  7. Interactions of Uranium with Polyphosphate

    SciTech Connect

    Vazquez,G.; Dodge, C.; Francis, A.

    2007-01-01

    Inorganic polyphosphates (PolyP) are simple linear phosphate (PO{sup 3-}{sub 4}) polymers which are produced by a variety of microorganisms. One of their functions is to complex metals resulting in their precipitation. We investigated the interaction of phosphate and low-molecular-weight PolyP (1400-1900 Da) with uranyl ion at various pHs. Potentiometric titration of uranyl ion in the presence of phosphate showed two sharp inflection points at pHs 4 and 8 due to uranium hydrolysis reaction and interaction with phosphate. Titration of uranyl ion and PolyP revealed a broad inflection point starting at pH 4 indicating that complexation of U-PolyP occurs over a wide range of pHs with no uranium hydrolysis. EXAFS analysis of the U-HPO4 complex revealed that an insoluble uranyl phosphate species was formed below pH 6; at higher pH (greater-or-equal, slanted8) uranium formed a precipitate consisting of hydroxophosphato species. In contrast, adding uranyl ion to PolyP resulted in formation of U-PolyP complex over the entire pH range studied. At low pH (less-than-or-equals, slant6) an insoluble U-PolyP complex having a monodentate coordination of phosphate with uranium was observed. Above pH 6 however, a soluble bidentate complex with phosphate and uranium was predominant. These results show that the complexation and solubility of uranium with PO4 and PolyP are dependent upon pH.

  8. Uranium phosphate biomineralization by fungi.

    PubMed

    Liang, Xinjin; Hillier, Stephen; Pendlowski, Helen; Gray, Nia; Ceci, Andrea; Gadd, Geoffrey Michael

    2015-06-01

    Geoactive soil fungi were investigated for phosphatase-mediated uranium precipitation during growth on an organic phosphorus source. Aspergillus niger and Paecilomyces javanicus were grown on modified Czapek-Dox medium amended with glycerol 2-phosphate (G2P) as sole P source and uranium nitrate. Both organisms showed reduced growth on uranium-containing media but were able to extensively precipitate uranium and phosphorus-containing minerals on hyphal surfaces, and these were identified by X-ray powder diffraction as uranyl phosphate species, including potassium uranyl phosphate hydrate (KPUO6 .3H2 O), meta-ankoleite [(K1.7 Ba0.2 )(UO2 )2 (PO4 )2 .6H2 O], uranyl phosphate hydrate [(UO2 )3 (PO4 )2 .4H2 O], meta-ankoleite (K(UO2 )(PO4 ).3H2 O), uramphite (NH4 UO2 PO4 .3H2 O) and chernikovite [(H3 O)2 (UO2 )2 (PO4 )2 .6H2 O]. Some minerals with a morphology similar to bacterial hydrogen uranyl phosphate were detected on A. niger biomass. Geochemical modelling confirmed the complexity of uranium speciation, and the presence of meta-ankoleite, uramphite and uranyl phosphate hydrate between pH 3 and 8 closely matched the experimental data, with potassium as the dominant cation. We have therefore demonstrated that fungi can precipitate U-containing phosphate biominerals when grown with an organic source of P, with the hyphal matrix serving to localize the resultant uranium minerals. The findings throw further light on potential fungal roles in U and P biogeochemistry as well as the application of these mechanisms for element recovery or bioremediation. PMID:25580878

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

    SciTech Connect

    Mac Donald, Philip Elsworth

    2002-09-01

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

  10. Distribution of uranium in rats implanted with depleted uranium pellets

    Microsoft Academic Search

    T. C. Pellmar; A. F. Fuciarelli; J. W. Ejnik; J. Hogan; S. Strocko; C. Emond; H. M. Mottaz; M. R. Landauer

    1999-01-01

    During the Persian Gulf War, soldiers were injured with de- pleted uranium (DU) fragments. To assess the potential health risks associated with chronic exposure to DU, Sprague Dawley rats were surgically implanted with DU pellets at 3 dose levels (low, medium and high). Biologically inert tantalum (Ta) pellets were used as controls. At 1 day and 6, 12, and 18

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

    SciTech Connect

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

    2012-07-25

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

  12. Process for alloying uranium and niobium

    DOEpatents

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

    1991-01-01

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

  13. Development of pulsed neutron uranium logging instrument.

    PubMed

    Wang, Xin-guang; Liu, Dan; Zhang, Feng

    2015-03-01

    This article introduces a development of pulsed neutron uranium logging instrument. By analyzing the temporal distribution of epithermal neutrons generated from the thermal fission of (235)U, we propose a new method with a uranium-bearing index to calculate the uranium content in the formation. An instrument employing a D-T neutron generator and two epithermal neutron detectors has been developed. The logging response is studied using Monte Carlo simulation and experiments in calibration wells. The simulation and experimental results show that the uranium-bearing index is linearly correlated with the uranium content, and the porosity and thermal neutron lifetime of the formation can be acquired simultaneously. PMID:25832251

  14. Development of pulsed neutron uranium logging instrument

    NASA Astrophysics Data System (ADS)

    Wang, Xin-guang; Liu, Dan; Zhang, Feng

    2015-03-01

    This article introduces a development of pulsed neutron uranium logging instrument. By analyzing the temporal distribution of epithermal neutrons generated from the thermal fission of 235U, we propose a new method with a uranium-bearing index to calculate the uranium content in the formation. An instrument employing a D-T neutron generator and two epithermal neutron detectors has been developed. The logging response is studied using Monte Carlo simulation and experiments in calibration wells. The simulation and experimental results show that the uranium-bearing index is linearly correlated with the uranium content, and the porosity and thermal neutron lifetime of the formation can be acquired simultaneously.

  15. Oxidation states of uranium in depleted uranium particles from Kuwait.

    PubMed

    Salbu, B; Janssens, K; Lind, O C; Proost, K; Gijsels, L; Danesi, P R

    2005-01-01

    The oxidation states of uranium in depleted uranium (DU) particles were determined by synchrotron radiation based mu-XANES, applied to individual particles isolated from selected samples collected at different sites in Kuwait. Based on scanning electron microscopy with X-ray microanalysis prior to mu-XANES, DU particles ranging from submicrons to several hundred micrometers were observed. The median particle size depended on sources and sampling sites; small-sized particles (median 13 microm) were identified in swipes taken from the inside of DU penetrators holes in tanks and in sandy soil collected below DU penetrators, while larger particles (median 44 microm) were associated with fire in a DU ammunition storage facility. Furthermore, the (236)U/(235)U ratios obtained from accelerator mass spectrometry demonstrated that uranium in the DU particles originated from reprocessed fuel (about 10(-2) in DU from the ammunition facility, about 10(-3) for DU in swipes). Compared to well-defined standards, all investigated DU particles were oxidized. Uranium particles collected from swipes were characterized as UO(2), U(3)O(8) or a mixture of these oxidized forms, similar to that observed in DU affected areas in Kosovo. Uranium particles formed during fire in the DU ammunition facility were, however, present as oxidation state +5 and +6, with XANES spectra similar to solid uranyl standards. Environmental or health impact assessments for areas affected by DU munitions should therefore take into account the presence of respiratory UO(2), U(3)O(8) and even UO(3) particles, their corresponding weathering rates and the subsequent mobilisation of U from oxidized DU particles. PMID:15511555

  16. Uranium 2014 resources, production and demand

    E-print Network

    Organisation for Economic Cooperation and Development. Paris

    2014-01-01

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

  17. Uranium 2005 resources, production and demand

    E-print Network

    Organisation for Economic Cooperation and Development. Paris

    2006-01-01

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

  18. Uranium 2011 resources, production and demand

    E-print Network

    Organisation for Economic Cooperation and Development. Paris

    2012-01-01

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

  19. The uranium enrichment enterprise controversy

    SciTech Connect

    Yates, M.

    1990-11-08

    This article addresses the controversy concerning the Uranium Enrichment Enterprise (UEE) of the US Department of Energy (US DOE). It discusses decontamination and decommissioning costs, competition by foreign competitors in a world market, the debate over the recovery of the governments costs in the program in a reasonable amount of time, various proposals to reorganize the UEE.

  20. Pulsed laser nitriding of uranium

    Microsoft Academic Search

    Yongbin Zhang; Daqiao Meng; Qinying Xu; Youshou Zhang

    2010-01-01

    Pulsed laser nitriding offers several advantages such as high nitrogen concentration, low matrix temperature, fast treatment, simple vacuum chamber and precise position control compare to ion implantation, which is favorable for radioactive material passivation. In this work, uranium metal was nitrided using an excimer laser for the first time. The nitrided layers are characterized by X-ray diffraction, X-ray photoelectron spectroscopy

  1. Civil use of depleted uranium

    Microsoft Academic Search

    Maria Betti

    2003-01-01

    In this paper the civilian exploitation of depleted uranium is briefly reviewed. Different scenarios relevant to its use are discussed in terms of radiation exposure for workers and the general public. The case of the aircraft accident which occurred in Amsterdam in 1992 involving a fire, is discussed in terms of the radiological exposure to bystanders.All information given has been

  2. Discordant Uranium-Lead Ages

    Microsoft Academic Search

    G. W. WETHERILL

    1963-01-01

    The solution to the equation for the diffusion of lead and uranium from a sphere, including the effect of a pulse of metamorphism, is applied to the problem of discordant U-Pb ages. It is found that a pulse of metamorphism can greatly disturb the straight-line pattern found by Tilton, and the implications of this with regard to the thermal history

  3. Uranium uptake by hydroponically cultivated crop plants.

    PubMed

    Soudek, Petr; Petrová, Sárka; Benešová, Dagmar; Dvo?áková, Marcela; Van?k, Tomáš

    2011-06-01

    Hydroponicaly cultivated plants were grown on medium containing uranium. The appropriate concentrations of uranium for the experiments were selected on the basis of a standard ecotoxicity test. The most sensitive plant species was determined to be Lactuca sativa with an EC(50) value about 0.1mM. Cucumis sativa represented the most resistant plant to uranium (EC(50)=0.71 mM). Therefore, we used the uranium in a concentration range from 0.1 to 1mM. Twenty different plant species were tested in hydroponic solution supplemented by 0.1mM or 0.5mM uranium concentration. The uranium accumulation of these plants varied from 0.16 mg/g DW to 0.011 mg/g DW. The highest uranium uptake was determined for Zea mays and the lowest for Arabidopsis thaliana. The amount of accumulated uranium was strongly influenced by uranium concentration in the cultivation medium. Autoradiography showed that uranium is mainly localized in the root system of the plants tested. Additional experiments demonstrated the possibility of influencing the uranium uptake from the cultivation medium by amendments. Tartaric acid was able to increase uranium uptake by Brassica oleracea and Sinapis alba up to 2.8 times or 1.9 times, respectively. Phosphate deficiency increased uranium uptake up to 4.5 times or 3.9 times, respectively, by Brassica oleracea and S. alba. In the case of deficiency of iron or presence of cadmium ions we did not find any increase in uranium accumulation. PMID:21486682

  4. Reactive transport modeling at uranium in situ recovery sites: uncertainties in uranium sorption on iron hydroxides

    USGS Publications Warehouse

    Johnson, Raymond H.; Tutu, Hlanganani

    2013-01-01

    Geochemical changes that can occur down gradient from uranium in situ recovery (ISR) sites are important for various stakeholders to understand when evaluating potential effects on surrounding groundwater quality. If down gradient solid-phase material consists of sandstone with iron hydroxide coatings (no pyrite or organic carbon), sorption of uranium on iron hydroxides can control uranium mobility. Using one-dimensional reactive transport models with PHREEQC, two different geochemical databases, and various geochemical parameters, the uncertainties in uranium sorption on iron hydroxides are evaluated, because these oxidized zones create a greater risk for future uranium transport than fully reduced zones where uranium generally precipitates.

  5. Magnesium bicarbonate as an in situ uranium lixiviant

    SciTech Connect

    Sibert, J.W.

    1984-09-25

    In the subsurface solution mining of mineral values, especially uranium, in situ, magnesium bicarbonate leaching solution is used instead of sodium, potassium and ammonium carbonate and bicarbonates. The magnesium bicarbonate solution is formed by combining carbon dioxide with magnesium oxide and water. The magnesium bicarbonate lixivant has four major advantages over prior art sodium, potassium and ammonium bicarbonates.

  6. National uranium resource evaluation, Montrose Quadrangle, Colorado

    SciTech Connect

    Goodknight, C.S.; Ludlam, J.R.

    1981-06-01

    The Montrose Quadrangle in west-central Colorado was evaluated to identify and delineate areas favorable for the occurrence of uranium deposits according to National Uranium Resource Evaluation program criteria. General surface reconnaissance and geochemical sampling were conducted in all geologic environments in the quadrangle. Preliminary data from aerial radiometric and hydrogeochemical and stream-sediment reconnaissance were analyzed and brief followup studies were performed. Twelve favorable areas were delineated in the quadrangle. Five favorable areas contain environments for magmatic-hydrothermal uranium deposits along fault zones in the Colorado mineral belt. Five areas in parts of the Harding and Entrada Sandstones and Wasatch and Ohio Creek Formations are favorable environments for sandstone-type uranium deposits. The area of late-stage rhyolite bodies related to the Lake City caldera is a favorable environment for hydroauthigenic uranium deposits. One small area is favorable for uranium deposits of uncertain genesis. All near-surface Phanerozoic sedimentary rocks are unfavorable for uranium deposits, except parts of four formations. All near-surface plutonic igneous rocks are unfavorable for uranium deposits, except five areas of vein-type deposits along Tertiary fault zones. All near-surface volcanic rocks, except one area of rhyolite bodies and several unevaluated areas, are unfavorable for uranium. All near-surface Precambrian metamorphic rocks are unfavorable for uranium deposits. Parts of two wilderness areas, two primitive areas, and most of the subsurface environment are unevaluated.

  7. REDUCTION DE L'OCTOOXYDE D'URANIUM EN DIOXYDE D'URANIUM PAR L'AMMONIAC

    E-print Network

    Paris-Sud XI, Université de

    REDUCTION DE L'OCTOOXYDE D'URANIUM EN DIOXYDE D'URANIUM PAR L'AMMONIAC P. Suhubiette1 , F'étude cinétique de la réduction de l'octooxyde d'uranium par l'ammoniac en dioxyde d'uranium. Cette réduction de l'octooxyde d'uranium par l'ammoniac, suivie par thermogravimétrie. L'équation stoechiométrique de

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

    E-print Network

    Matthews, Isaac A

    2010-01-01

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

  9. Uranium and plutonium isotopes in the atmosphere

    SciTech Connect

    Sakuragi, Y.; Meason, J.L.; Kuroda, P.K.

    1983-04-20

    Uranium 234 and 235 were found to be highly enriched relative to uranium 238 in several rain samples collected at Fayetteville, Arkansas, during the months of April and May 1980. The anomalous uranium appears to have originated from the Soviet satellite Cosmos-954, which fell over Canada on January 24, 1978. The uranium fallout occurred just about the time Mount St. Helens erupted on May 18, 1980. The concentration of /sup 238/U in rain increased markedly after the eruption of Mount St. Helens, and it appeared as if a large quantity of natural uranium was injected into the atmosphere by the volcanic eruption. The pattern of variation of the concentrations of uranium in rain after the eruption of Mount St. Helens was found to be similar to that of plutonium isotopes.

  10. Uranium 2009 resources, production and demand

    E-print Network

    Organisation for Economic Cooperation and Development. Paris

    2010-01-01

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

  11. Removal of uranium by biosorption

    SciTech Connect

    Faison, B.D.; Bonner, J.D. [Oak Ridge National Lab., TN (US); Munroe, N.D. [Florida International Univ., Miami, FL (US). Dept. of Mechanical Engineering; Bloomingburg, G.F. [Univ. of Tennessee, Knoxville, TN (US). Dept. of Chemical Engineering

    1993-06-01

    The technology developed here will exploit the ability of microorganisms to remove dissolved metals from aqueous solutions. Microbial sorbents for uranium will be immobilized biosorbents will be deployed ex situ within flow-through reactors for the continuous or semicontinuous treatment of recovered wastewaters. The proposed technology will primarily be applied within a pump-and-treat process using immobilized biosorbents for the large-scale, long-term remediation of uranium-laden surface water or groundwater impoundments (environmental restoration). The technology may be equally useful as an ``end-of-pipe`` treatment of process effluents (waste management). Successful operation of this process will achieve immobilization of the targeted waste and accompanying volume reduction.

  12. Modeling of geochemical processes related to uranium mobilization in the groundwater of a uranium mine

    Microsoft Academic Search

    P. Gómez; A. Garralón; B. Buil; Ma. J. Turrero; L. Sánchez; B. de la Cruz

    2006-01-01

    This paper describes the processes leading to uranium distribution in the groundwater of five boreholes near a restored uranium mine (dug in granite), and the environmental impact of restoration work in the discharge area. The groundwater uranium content varied from <1 ?g\\/L in reduced water far from the area of influence of the uranium ore-containing dyke, to 104 ?g\\/L in

  13. Influence of Uranium on Bacterial Communities: A Comparison of Natural Uranium-Rich Soils with Controls

    Microsoft Academic Search

    Laure Mondani; Karim Benzerara; Marie Carrière; Richard Christen; Yannick Mamindy-Pajany; Laureline Février; Nicolas Marmier; Wafa Achouak; Pascal Nardoux; Catherine Berthomieu; Virginie Chapon

    2011-01-01

    This study investigated the influence of uranium on the indigenous bacterial community structure in natural soils with high uranium content. Radioactive soil samples exhibiting 0.26% - 25.5% U in mass were analyzed and compared with nearby control soils containing trace uranium. EXAFS and XRD analyses of soils revealed the presence of U(VI) and uranium-phosphate mineral phases, identified as sabugalite and

  14. Description of the Canadian particulate-fill waste-package (WP) system for spent-nuclear fuel (SNF) and its applicability to light-water reactor SNF WPs with depleted uranium-dioxide fill

    SciTech Connect

    Forsberg, C.W.

    1997-10-20

    The US is beginning work on an advanced, light-water reactor (LWR), spent nuclear fuel (SNF), waste package (WP) that uses depleted uranium dioxide (UO{sub 2}) fill. The Canadian nuclear fuel waste management program has completed a 15-year development program of its repository concept for CANadian Deuterium Uranium (CANDU) reactor SNF. As one option, Canada has developed a WP that uses a glass-bead or silica-sand fill. The Canadian development work on fill materials inside WPs can provide a guide for the development of LWR SNF WPs using depleted uranium (DU) fill materials. This report summarizes the Canadian work, identifies similarities and differences between the Canadian design and the design being investigated in the US to use DU fill, and identifies what information is applicable to the development of a DU fill for LWR SNF WPs. In both concepts, empty WPs are loaded with SNF, the void space between the fuel pins and the outer void space between SNF assemblies and the inner WP wall would be filled with small particles, the WPs are then sealed, and the WPs are placed into the repository.

  15. Luminescence of powdered uranium glasses

    NASA Technical Reports Server (NTRS)

    Eubanks, A. G.; Mcgarrity, J. M.; Silverman, J.

    1974-01-01

    Measurement of cathodoluminescence and photoluminescence efficiencies in powdered borosilicate glasses having different particle size and different uranium content. Excitation with 100 to 350 keV electrons and with 253.7 nm light was found to produce identical absolute radiant exitance spectra in powdered samples. The most efficient glass was one containing 29.4 wt% B2O3, 58.8 wt% SiO2, 9.8 wt% Na2O and 2.0 wt% UO2.

  16. Assessment of rehabilitated uranium mine sites, Australia

    Microsoft Academic Search

    Bernd Lottermoser; Paul Ashley

    \\u000a Recent research on rehabilitated uranium mine sites located in wet climates has revealed the varied success of the applied\\u000a rehabilitation efforts. In comparison, there is little knowledge of the status and environmental impacts of rehabilitated\\u000a uranium mines in dry climates. Mary Kathleen and Radium Hill represent first generation Australian uranium mines, which are\\u000a located in semi-arid regions. The aim of

  17. 300 Area Uranium Leach and Adsorption Project

    Microsoft Academic Search

    R. Jeffrey Serne; Christopher F. Brown; Herbert T. Schaef; Eric M. Pierce; Michael J. Lindberg; Zheming Wang; Paul L. Gassman; J. G. Catalano

    2002-01-01

    The objective of this study was to measure the leaching and adsorption characteristics of uranium in six near-surface sediment samples collected from the 300 Area of the Hanford Site. Scanning electron micrographs of the samples showed that the uranium contamination in the sediments is most likely present as co-precipitates and\\/or discrete uranium particles. Molecular probe techniques also confirm the presence

  18. Welding of a powder metallurgy uranium alloy

    Microsoft Academic Search

    R. K. Holbert; M. W. Doughty; G. M. Alexander-Morrison

    1989-01-01

    The interest at the Oak Ridge Y-12 Plant in powder metallurgy (P\\/M) uranium parts is due to the potential cost savings in the fabrication of the material, to achieving a more homogeneous product, and to the reduction of uranium scrap. The joining of P\\/M uranium-6 wt-% niobium (U-6Nb) alloys by the electron beam (EB) welding process results in weld porosity.

  19. URANIUM RECOVERY AND PURIFICATION PROCESS AND PRODUCTION OF HIGH PURITY URANIUM TETRAFLUORIDE

    Microsoft Academic Search

    R. H. Bailes; R. S. Long; R. R. Grinstead

    1962-01-01

    A process is outlined for separating uranium from a large variety of ; impurities to give a purified solution from which pure UFâ can be obtained. ; The process comprises forming a solution containing >5 M chloride and the ; contaminated uranium, passing the solution through an anionic exchange resin to ; adsorb the anionic uranium chloride complexes and some

  20. Possible uranium sources for the largest uranium district associated with volcanism: the Streltsovka caldera (Transbaikalia, Russia)

    Microsoft Academic Search

    Aliouka Chabiron; Michel Cuney; Bernard Poty

    2003-01-01

    The uranium deposits of the Late Jurassic Streltsovka caldera (Transbaikalia, Russia) represent the largest uranium field associated with volcanics in the world (280,000 t U) and Russia's largest uranium resources. About one third of the caldera stratigraphic pile consists of rhyolites which are strongly altered. The rhyolitic magma preserved as melt inclusions in quartz phenocrysts corresponds to a mildly peralkaline

  1. Colorimetric detection of uranium in water

    DOEpatents

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

    2012-03-13

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

  2. In Vivo Nanodetoxication for Acute Uranium Exposure.

    PubMed

    Guzmán, Luis; Durán-Lara, Esteban F; Donoso, Wendy; Nachtigall, Fabiane M; Santos, Leonardo S

    2015-01-01

    Accidental exposure to uranium is a matter of concern, as U(VI) is nephrotoxic in both human and animal models, and its toxicity is associated to chemical toxicity instead of radioactivity. We synthesized different PAMAM G4 and G5 derivatives in order to prove their interaction with uranium and their effect on the viability of red blood cells in vitro. Furthermore, we prove the effectiveness of the selected dendrimers in an animal model of acute uranium intoxication. The dendrimer PAMAM G4-Lys-Fmoc-Cbz demonstrated the ability to chelate the uranyl ion in vivo, improving the biochemical and histopathologic features caused by acute intoxication with uranium. PMID:26083036

  3. Uranium by controlled-potential coulometry

    SciTech Connect

    Not Available

    1981-01-01

    The method covers the determination of milligram amounts of uranium by controlled-potential coulometry. The determination is based on the direct electrolytic reduction of uranium(VI) at a mercury cathode under conditions such that the electrolysis proceeds with virtually 100% current efficiency, that is, under conditions such that the amount of electricity required to accomplish complete reduction is a measure of the amount of uranium(VI) present. The method includes a discussion of interferences, apparatus, reagents and materials, calibration of the integrator, separation procedure, coulometric determination of uranium(VI), calculations, precision, and accuracy. (JMT)

  4. Chemistry of uranium in aluminophosphate glasses

    NASA Technical Reports Server (NTRS)

    Schreiber, H. D.; Balazs, G. B.; Williams, B. J.

    1982-01-01

    The U(VI)-U(V)-U(IV) redox equilibria are investigated in two sodium aluminophosphate base compositions at a variety of melt temperatures, imposed oxygen fugacities, and uranium contents. Results show that the higher redox states of uranium are quite soluble in the phosphate glasses, although U(IV) readily precipitates from the melts as UO2. In addition, comparisons of the uranium redox equilibria established in phosphate melts versus those in silicate melts shows that the coordination sites of the individual uranium species are generally the same in both solvent systems although they differ in detail.

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

    SciTech Connect

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

    1993-12-31

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

  6. High strength and density tungsten-uranium alloys

    DOEpatents

    Sheinberg, Haskell (Los Alamos, NM)

    1993-01-01

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

  7. Potential environmental impact resulting from inadequate remediation of uranium mining in the Karoo Uranium Province, South Africa

    Microsoft Academic Search

    Nico Scholtz; O. F. Scholtz; Gerhard P. Potgieter

    Inadequate remediation of uranium mining in the Karoo Uranium Province, South Africa led to a disused open pit and inclined shaft, uranium ore in stockpiles and barrels, as well as other mining related equipment.

  8. Synthesis and characterization of uranium (IV) phosphate-hydrogenphosphate hydrate and cerium (IV) phosphate-hydrogenphosphate hydrate

    Microsoft Academic Search

    V.. Brandel; N. Clavier; N.. Dacheux

    2005-01-01

    A new uranium (IV) phosphate of proposed formula U2(PO4)2HPO4·H2O, i.e. uranium phosphate-hydrogenphosphate hydrate (UPHPH), was synthesized in autoclave and\\/or in polytetrafluoroethylene closed containers at 150°C by three ways: from uranium (IV) hydrochloric solution and phosphoric acid, from uranium dioxide and phosphoric acid and by transformation of the uranium hydrogenphosphate hydrate U(HPO4)2·nH2O. The new product appears similar to the previously published

  9. Uranium and Aluminosilicate Surface Precipitation Tests

    SciTech Connect

    Hu, M.Z.

    2002-11-27

    The 2H evaporator at the Savannah River Site has been used to treat an aluminum-rich waste stream from canyon operations and a silicon-rich waste stream from the Defense Waste Processing Facility. The formation of aluminosilicate scale in the evaporator has caused significant operational problems. Because uranium has been found to accumulate in the aluminosilicate solids, the scale deposition has introduced criticality concerns as well. The objective of the tests described in this report is to determine possible causes of the uranium incorporation in the evaporator scale materials. The scope of this task is to perform laboratory experiments with simulant solutions to determine if (1) uranium can be deposited on the surfaces of various sodium aluminosilicate (NAS) forms and (2) aluminosilicates can form on the surfaces of uranium-containing solids. Batch experiments with simulant solutions of three types were conducted: (1) contact of uranium solutions/sols with NAS coatings on stainless steel surfaces, (2) contact of uranium solutions with NAS particles, and (3) contact of precipitated uranium-containing particles with solutions containing aluminum and silicon. The results show that uranium can be incorporated in NAS solids through encapsulation in bulk agglomerated NAS particles of different phases (amorphous, zeolite A, sodalite, and cancrinite) as well as through heterogeneous deposition on the surfaces of NAS coatings (amorphous and cancrinite) grown on stainless steel. The results also indicate that NAS particles can grow on the surfaces of precipitated uranium solids. Particularly notable for evaporator operations is the finding that uranium solids can form on existing NAS scale, including cancrinite solids. If NAS scale is present, and uranium is in sufficient concentration in solution to precipitate, a portion of the uranium can be expected to become associated with the scale. The data obtained to date on uranium-NAS affinity are qualitative. A necessary next step is to quantitatively determine the amounts of uranium that may be incorporated into NAS scale solids under differing conditions e.g., varying silicon/aluminum ratio, uranium concentration, temperature, and deposition time.

  10. An original precipitation route toward the preparation and the sintering of highly reactive uranium cerium dioxide powders

    NASA Astrophysics Data System (ADS)

    Martinez, J.; Clavier, N.; Mesbah, A.; Audubert, F.; Le Goff, X. F.; Vigier, N.; Dacheux, N.

    2015-07-01

    The preparation of dense U1-xCexO2 mixed dioxides pellets was achieved from the initial precipitation of highly reactive precursors. In a first step, a wet chemistry route, based on the mixture of U4+ and Ce4+ in acidic solution with large excess of NH4OH, was set up to reach the precipitation of the cations. The solid phase was then dried under vacuum to avoid aggregation phenomena. Further characterization of the powders by XRD, EDS and TEM revealed the formation of hydrated U1-xCexO2?nH2O that probably resulted from the aging of hydroxide compounds. Also, microscopy investigations evidenced the nanosized character of the powder which was associated to high values of specific surface area, typically in the 100-150 m2 g-1 range. The behavior of U1-xCexO2?nH2O versus temperature was investigated in a second part. If the increase of the heat temperature allowed one to observe an improvement of the crystallization state linked with the growth of crystallites, it was also accompanied by a strong decrease of the powders reactivity. On this basis, sintering tests were conducted in reducing atmosphere on the compounds as prepared. Dilatometry experiments indicated a low densification temperature compared to other ways of preparation reported in the literature. Also, the pellets prepared after firing at different temperatures (1350-1550 °C) showed that a wide range of microstructures was achievable. Particularly, bulk materials with densities of 90-95% of the calculated value could be prepared with average grain size ranging from around 100 nm to more than 5 ?m. This simple process of elaboration of dense materials from highly reactive hydrated oxide precursor thus appears as a very interesting way to prepare actinide oxides materials.

  11. Characterization of uranium and uranium-zirconium deposits produced in electrorefining of spent nuclear fuel

    SciTech Connect

    Totemeier, T.C.

    1997-09-01

    This paper describes the metallurgical characterization of deposits produced in molten salt electrorefining of uranium and uranium - 10.% zirconium alloy. The techniques of characterization are described with emphasis on considerations given to the radioactive and pyrophoric nature of the samples. The morphologies observed and their implications for deposit performance are also presented - samples from pure uranium deposits were comprised of chains of uranium crystals with a characteristic rhomboidal shape, while morphologies of samples from deposits containing zirconium showed more polycrystalline features. Zirconium was found to be present as a second, zirconium metal phase at or very near the uranium-zirconium dendrite surfaces. Higher collection efficiencies and total deposit weights were observed for the uranium-zirconium deposits; this performance increase is likely a result of better mechanical properties exhibited by the uranium-zirconium dendrite morphology. 18 refs., 10 figs., 1 tab.

  12. Modeled atmospheric radon concentrations from uranium mines

    Microsoft Academic Search

    Droppo

    1985-01-01

    Uranium mining and milling operations result in the release of radon from numerous sources of various types and strengths. The US Environmental Protection Agency (EPA) under the Clean Air Act, is assessing the health impact of air emissions of radon from underground uranium mines. In this case, the radon emissions may impact workers and residents in the mine vicinity. To

  13. PHYSICAL PROPERTIES OF URANIUM PROCESS SOLUTIONS

    Microsoft Academic Search

    Ondrejcin

    1961-01-01

    Integral diffusion coefficients, viscosities, densities, and surface ;\\u000a tensions were measured for the aqueous uranyl nitrate --nitric acid--aluminum ;\\u000a nitrate system. The variation of the uranium diffusion coefficient was ;\\u000a determined as as a function of uranium concentration, nitric acid concentration, ;\\u000a and temperature. (auth)

  14. National Uranium Resource Evaluation: Casper Quadrangle, Wyoming

    Microsoft Academic Search

    J. R. Griffin; E. J. Milton

    1982-01-01

    The Casper Quadrangle, Wyoming, was evaluated for areas favorable for the occurrence of uranium deposits. Examination of surface exposures of known uranium occurrences, reconnaissance geochemical sampling, and ground radiometric surveys were conducted. Anomalous areas recognized from airborne radiometric surveys were ground checked. Electric and gamma logs were used to determine subsurface structure, stratigraphy, lithology, and areas of anomalous radioactivity. Fourteen

  15. National Uranium Resource Evaluation, Leadville Quadrangle, Colorado

    Microsoft Academic Search

    D. B. Collins; D. C. Graham; A. L. Hornbaker

    1982-01-01

    The Leadville Quadrangle in northwestern Colorado was evaluated to identify and delineate areas favorable for the occurrence of uranium according to National Uranium Resource Evaluation criteria. General surface reconnaissance and geochemical sampling were carried out in all geologic environments within the quadrangle. Preliminary data from an aerial radiometric reconnaissance were analyzed, and brief ground checks were performed. Eight favorable areas

  16. UPTAKE OF URANIUM FROM DRINKING WATER

    EPA Science Inventory

    The gastrointestinal absorption (G.I.) of uranium in man from drinking water was determined by measuring urinary and fecal excretion of 234U and 238U in eight subjects. In order to establish their normal backgrounds of uranium intake and excretion, the subjects collected 24 hour ...

  17. Uzbekistan unveiled. [Uranium production to commence

    SciTech Connect

    Mazurkevich, A.P.

    1993-05-01

    Through centuries of revolution, war and strife, the people of Uzbekistan have built a reputation as skilled and tenacious merchants. Since antiquity, when the Silk Road from China turned toward Europe at Smarakand, they have been master traders of such valuable commodities as cotton, fruits, vegetables, spices and gold. Now, they're about to introduce another of their specialties to the world: Uranium. Uranium mining in the country is controlled by a new, independent company, the Kizilkumredmetzoloto, parent of the Navoi Mining Metallurgy Combine [NMMC]. Established in 1958 at the height of the Cold War, when uranium mining for military stockpiles got started in earnest, Navoi was wholly owned by the USSR's Ministry of Medium Machine Building. Up until 1991, virtually all of Navoi's uranium production, strictly in the form of uranium concentrates, was used for either military purposes or for nuclear power plants within the former Soviet Union. The republic exerted no control over the final destination of its uranium. All production and operating decisions for Navoi's mines were dictated by the Soviet Union's Ministry of Atomic Power Industry [MAPI], which developed annual quotas for uranium production in each republic of the country. Uranium from the republics was sold to Techsnabexport [Tenex], the distribution and marketing arm of MAPI. Exports to other countries were handled strictly by Tenex.

  18. Depleted uranium--the growing concern.

    PubMed

    Abu-Qare, Aqel W; Abou-Donia, Mohamed B

    2002-01-01

    Recently, several studies have reported on the health and environmental consequences of the use of depleted uranium. Depleted uranium is a heavy metal that is also radioactive. It is commonly used in missiles as a counterweight because of its very high density (1.6 times more than lead). Immediate health risks associated with exposure to depleted uranium include kidney and respiratory problems, with conditions such as kidney stones, chronic cough and severe dermatitis. Long-term risks include lung and bone cancer. Several published reports implicated exposure to depleted uranium in kidney damage, mutagenicity, cancer, inhibition of bone, neurological deficits, significant decrease in the pregnancy rate in mice and adverse effects on the reproductive and central nervous systems. Acute poisoning with depleted uranium elicited renal failure that could lead to death. The environmental consequences of its residue will be felt for thousands of years. It is inhaled and passed through the skin and eyes, transferred through the placenta into the fetus, distributed into tissues and eliminated in urine. The use of depleted uranium during the Gulf and Kosovo Wars and the crash of a Boeing airplane carrying depleted uranium in Amsterdam in 1992 were implicated in a health concern related to exposure to depleted uranium. PMID:12015793

  19. Bioremediation of uranium contaminated soils and wastes

    SciTech Connect

    Francis, A.J.

    1998-12-31

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

  20. The United States Uranium Industry, 1993

    Microsoft Academic Search

    1993-01-01

    Low prices and foreign competition continue to plague the United States uranium industry. For eight years (1984-1991) the Secretary of Energy has declared the industry to be nonviable. A similar declaration is expected late in 1993 for 1992. Surface drilling for uranium in 1993 is expected to be about 1 million ft., because deposits are developed prior to mining. Drilling

  1. Radiological aspects of in situ uranium recovery

    Microsoft Academic Search

    STEVEN H

    2007-01-01

    In the last few years, there has been a significant increase in the demand for Uranium as historical inventories have been consumed and new reactor orders are being placed. Numerous mineralized properties around the world are being evaluated for Uranium recovery and new mining \\/ milling projects are being evaluated and developed. Ore bodies which are considered uneconomical to mine

  2. Defining Conditions for Maximizing Bioreduction of Uranium

    Microsoft Academic Search

    David C. White; Aaron D. Peacock; Yun-Juan Chang; Roland Geyer; Philip E. Long; Jonathan D. Istok; Amanda N; Smithgall; R. Todd Anderson; Dora Ogles

    2004-01-01

    Correlations between modifying electron donor and acceptor accessibility, the in-situ microbial community, and bioreduction of Uranium at the FRC and UMTRA research sites indicated that significant modifications in the rate, amount and by inference the potential stability of immobilized Uranium are feasible in these environments. The in-situ microbial community at these sites was assessed with a combination of lipid and

  3. National Uranium Resource Evaluation: Pratt Quadrangle, Kansas

    Microsoft Academic Search

    C. L. Fair; D. E. Smit

    1982-01-01

    Surface reconnaissance and detailed subsurface studies were done within the Pratt Quadrangle, Kansas, to evaluate uranium favorability using National Uranium Resource Evaluation criteria. These studies were designed in part to follow up previous airborne radiometric, hydrogeochemical, and stream-sediment surveys. More than 8100 well records were examined in the subsurface phase of this study. Results of these investigations indicate no environments

  4. Hydrogen absorption properties of uranium alloys

    Microsoft Academic Search

    K. Asada; K. Ono; K. Yamaguchi; T. Yamamoto; A. Maekawa; S. Oe; M. Yamawaki

    1995-01-01

    Hydrogen absorption and desorption properties of U?Ti and U?Zr alloys were investigated at hydrogen pressures below 105 Pa and temperatures up to 873 K. Under such conditions, some uranium alloys showed as good characteristics as pure uranium and resulted in less degree of powderization after hydrogenation under an atmospheric pressure.

  5. 31 CFR 540.309 - Natural uranium.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    31 ? Money and Finance:Treasury ? 3 ? 2014-07-01 ? 2014-07-01 ? false ? Natural uranium. ? 540.309 ? Section 540.309 ? Money and Finance: Treasury ? Regulations Relating to Money and Finance (Continued) ? OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ? HIGHLY ENRICHED URANIUM...

  6. OPERATION OF SMALL SCALE URANIUM REMOVAL SYSTEMS

    EPA Science Inventory

    The design and Operation of a small full-scale ion exchange system used to remove uranium from well water in the foothills west of Denver, Colo., are described. onsistent removal of uranium was accomplished by anion exchange treatment at a reasonable cost. ecause of a lack of cle...

  7. 31 CFR 540.309 - Natural uranium.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    31 ? Money and Finance:Treasury ? 3 ? 2013-07-01 ? 2013-07-01 ? false ? Natural uranium. ? 540.309 ? Section 540.309 ? Money and Finance: Treasury ? Regulations Relating to Money and Finance (Continued) ? OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ? HIGHLY ENRICHED URANIUM...

  8. ENVIRONMENTAL OVERVIEW OF UNCONVENTIONAL EXTRACTION OF URANIUM

    EPA Science Inventory

    Uranium mining areas in the United States are identified and briefly described, and the geologic, geochemical, and hydrologic factors associated with the various types of ore deposits are discussed. Uranium deposits that are now being mined or have recently been mined by solution...

  9. 31 CFR 540.309 - Natural uranium.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    31 ? Money and Finance:Treasury ? 3 ? 2012-07-01 ? 2012-07-01 ? false ? Natural uranium. ? 540.309 ? Section 540.309 ? Money and Finance: Treasury ? Regulations Relating to Money and Finance (Continued) ? OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ? HIGHLY ENRICHED URANIUM...

  10. 31 CFR 540.309 - Natural uranium.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    31 ? Money and Finance:Treasury ? 3 ? 2011-07-01 ? 2011-07-01 ? false ? Natural uranium. ? 540.309 ? Section 540.309 ? Money and Finance: Treasury ? Regulations Relating to Money and Finance (Continued) ? OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ? HIGHLY ENRICHED URANIUM...

  11. 31 CFR 540.309 - Natural uranium.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    31 ? Money and Finance: Treasury ? 3 ? 2010-07-01 ? 2010-07-01 ? false ? Natural uranium. ? 540.309 ? Section 540.309 ? Money and Finance: Treasury ? Regulations Relating to Money and Finance (Continued) ? OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ? HIGHLY ENRICHED URANIUM...

  12. Scrap uranium recycling via electron beam melting

    SciTech Connect

    McKoon, R.

    1993-11-01

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

  13. Molten-Salt Depleted-Uranium Reactor

    E-print Network

    Dong, Bao-Guo; Gu, Ji-Yuan

    2015-01-01

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

  14. National Uranium Resource Evaluation, Tonopah quadrangle, Nevada

    SciTech Connect

    Hurley, B W; Parker, D P

    1982-04-01

    The Tonopah Quadrangle, Nevada, was evaluated using National Uranium Resource Evaluation criteria to identify and delineate areas favorable for uranium deposits. Investigations included reconnaissance and detailed surface geologic and radiometric studies, geochemical sampling and evaluation, analysis and ground-truth followup of aerial radiometric and hydrogeochemical and stream-sediment reconnaissance data, and subsurface data evaluation. The results of these investigations indicate environments favorable for hydroallogenic uranium deposits in Miocene lacustrine sediments of the Big Smoky Valley west of Tonopah. The northern portion of the Toquima granitic pluton is favorable for authigenic uranium deposits. Environments considered unfavorable for uranium deposits include Quaternary sediments; intermediate and mafic volcanic and metavolcanic rocks; Mesozoic, Paleozoic, and Precambrian sedimentary and metasedimentary rocks; those plutonic rocks not included within favorable areas; and those felsic volcanic rocks not within the Northumberland and Mount Jefferson calderas.

  15. Method for fabricating laminated uranium composites

    DOEpatents

    Chapman, L.R.

    1983-08-03

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

  16. Mica Surfaces Stabilize Pentavalent Uranium

    SciTech Connect

    Ilton, Eugene S.; Haiduc, Anca; Cahill, Christopher L.; Felmy, Andrew R.

    2005-05-02

    We used high-resolution x-ray photoelectron spectroscopy to demonstrate that reduction of aqueous U6+ at ferrous mica surfaces at 25oC preserves U5+ as the dominant sorbed species over a broad range of solution compositions. Polymerization of sorbed U5+ with sorbed U6+ and U4+ is identified as a possible mechanism for how mineral surfaces circumvent the rapid disproportionation of aqueous U5+. The general nature of this mechanism suggests that U5+ could play an important, but previously unidentified, role in the low–temperature chemistry of uranium in reducing, heterogeneous aqueous systems.

  17. Deep drawing of uranium metal

    SciTech Connect

    Jackson, R J; Lundberg, M R

    1987-01-19

    A procedure was developed to fabricate uranium forming blanks with high ''draw-ability'' so that cup shapes could be easily and uniformly deep drawn. The overall procedure involved a posttreatment to develop optimum mechanical and structural properties in the deep-drawn cups. The fabrication sequence is casting high-purity logs, pucking cast logs, cross-rolling pucks to forming blanks, annealing and outgassing forming blanks, cold deep drawing to hemispherical shapes, and stress relieving, outgassing, and annealing deep-drawn parts to restore ductility and impart dimensional stability. The fabrication development and the resulting fabrication procedure are discussed in detail. The mechanical properties and microstructural properties are discussed.

  18. Environmental problems relating to uranium mining and milling

    Microsoft Academic Search

    1979-01-01

    Regulation of the environmental impacts of uranium mining and milling is becoming increasingly more stringent. The major environmental legal issues relating to uranium mining and milling are discussed. Environmental problems associated with in situ mining are also considered. Areas examined are: federal jurisdiction over uranium mining and milling; state jurisdiction over uranium mining and milling; the impact of the Safe

  19. METHODS FOR REMOVING URANIUM FROM DRINKING WATER (JOURNAL VERSION)

    EPA Science Inventory

    The number of water supplies with high uranium levels and the possibility of a national uranium regulation has stimulated greater interest in uranium removal technology. The paper summarizes recent information on the effectiveness of various methods for uranium removal from drink...

  20. Surficial origin of North American pitchblende and related uranium deposits

    Microsoft Academic Search

    Langford

    1977-01-01

    The ubiquitous association of pitchblende uranium deposits with terrestrial sediments is believed to be the natural result of formation of the orebodies by surficial processes operating under continental conditions. The major uranium deposits of North America illustrate this. The quartz-pebble conglomerate uranium deposits of Elliot Lake, Ontario, have thorium-rich uranium minerals that indicate a detrital origin. With the development of

  1. DEPLETED AND NATURAL URANIUM: CHEMISTRY AND TOXICOLOGICAL EFFECTS

    Microsoft Academic Search

    Elena S. Craft; Aquel W. Abu-Qare; Meghan M. Flaherty; Melissa C. Garofolo; Heather L. Rincavage; Mohamed B. Abou-Donia

    2004-01-01

    Depleted uranium (DU) is a by-product from the chemical enrichment of naturally occurring uranium. Natural uranium is comprised of three radioactive isotopes: U, U, and U. This enrichment process reduces the radioactivity of DU to roughly 30% of that of natural uranium. Nonmilitary uses of DU include counterweights in airplanes, shields against radiation in medical radiotherapy units and transport of

  2. Carbon reduction in uranium alloys utilizing hafnium additions

    Microsoft Academic Search

    G. Mackiewicz-Ludtka; W. C. Pullen; C. A. Henderson; W. Chu; M. W. Wendel

    1990-01-01

    With increasing environmental concerns regarding the handling and storage of uranium waste, recycling previously used material is becoming exceedingly more important. Carbon is one of the primary trace impurities that builds up in uranium with repeated use. The goal of this study is to reduce carbon in recycled uranium during the casting process to carbon levels associated with virgin uranium

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

    E-print Network

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

  4. Uranium Pyrophoricity Phenomena and Prediction

    SciTech Connect

    DUNCAN, D.R.

    2000-04-20

    We have compiled a topical reference on the phenomena, experiences, experiments, and prediction of uranium pyrophoricity for the Hanford Spent Nuclear Fuel Project (SNFP) with specific applications to SNFP process and situations. The purpose of the compilation is to create a reference to integrate and preserve this knowledge. Decades ago, uranium and zirconium fires were commonplace at Atomic Energy Commission facilities, and good documentation of experiences is surprisingly sparse. Today, these phenomena are important to site remediation and analysis of packaging, transportation, and processing of unirradiated metal scrap and spent nuclear fuel. Our document, bearing the same title as this paper, will soon be available in the Hanford document system [Plys, et al., 2000]. This paper explains general content of our topical reference and provides examples useful throughout the DOE complex. Moreover, the methods described here can be applied to analysis of potentially pyrophoric plutonium, metal, or metal hydride compounds provided that kinetic data are available. A key feature of this paper is a set of straightforward equations and values that are immediately applicable to safety analysis.

  5. Pressure dependence of extraction behavior of plutonium(IV) and uranium(VI) from nitric acid solution to supercritical carbon dioxide containing tributylphosphate

    Microsoft Academic Search

    Shuichi Iso; Seiichiro Uno; Yoshihiro Meguro; Takayuki Sasaki; Zenko Yoshida

    2000-01-01

    Plutonium(IV) and uranium(VI) were extracted into supercritical CO2 fluid phase (SF-CO2) containing tributylphosphate (TBP) with equilibrium distribution ratios, D, e. g., DPu(IV) = 3.1 and DU(IV) = 2.0, for the extraction of 2 × 10?3 M Pu(IV) and U(VI) from 3 M HNO3 into SF-CO2 containing 0.3 M TBP at 60 °C and 15 MPa. A simple linear relation between

  6. Renal toxicity in uranium mill workers.

    PubMed

    Thun, M J; Baker, D B; Steenland, K; Smith, A B; Halperin, W; Berl, T

    1985-04-01

    Although the kidney is the critical organ limiting occupational exposure to soluble uranium compounds, there have been no adequate studies evaluating renal tubular dysfunction in chronically exposed workers. The present investigation evaluated kidney function among 39 uranium mill workers and 36 local cement plant workers of equivalent age, sex, and race. The uranium workers showed a significantly higher excretion of beta-2-microglobulin and five amino acids than the reference group. Although the levels of tubular proteinuria were mild, a dose-effect relation existed between the clearance of beta-2-microglobulin, relative to that of creatinine, and the length of time that the uranium workers had spent in the yellowcake drying and packaging area, the work area with the highest exposures to soluble uranium. Age did not account for this relationship. Glomerular function was significantly better among the uranium workers than among the referents, though this may have been the result of differences in the physical activity of the groups during the collection period. The data presented suggest reduced renal proximal tubular reabsorbtion of amino acids and of low molecular weight proteins, consistent with uranium nephrotoxicity. PMID:3890163

  7. Dynamic Response of High Temperature Uranium Phases

    NASA Astrophysics Data System (ADS)

    Zaretsky, E.; Herrmann, B.; Shvarts, D.

    2006-07-01

    Unalloyed uranium and uranium-0.78 wt%Ti alloy were studied in planar impact experiments with initial sample temperature ranging from 27 to 860°C. The velocity of the free surface of the samples was monitored by VISAR. It was found that the dynamic compressive strength of both the materials undergoes two-fold increase in the narrow temperature interval corresponding to the domain of beta-phase of uranium. The increase is followed by abrupt, factor of 3-4, strength drop when the initial state of the tested material is gamma-uranium. Such strength behavior explains the uranium susceptibility to adiabatic shear banding. The spall strength of both the alloys is characterized by similar temperature variations. The strength mechanism (phonon viscosity) acting in gamma-phase of pure uranium seems inherited from its alpha-structure while the strength of beta-uranium is controlled by high resistance to shearing characteristic for material having the structure of intermetallic sigma-phase.

  8. Dynamic Response of High Temperature Uranium Phases

    SciTech Connect

    Zaretsky, E. [Mechanical Engineering Dept., Ben Gurion University, P.O. Box 653, Beer-Sheva 84105 (Israel); Herrmann, B.; Shvarts, D. [Nuclear Research Center -- Negev, P.O.Box 9001, Beer-Sheva 84106 (Israel)

    2006-07-28

    Unalloyed uranium and uranium-0.78 wt%Ti alloy were studied in planar impact experiments with initial sample temperature ranging from 27 to 860 degree sign C. The velocity of the free surface of the samples was monitored by VISAR. It was found that the dynamic compressive strength of both the materials undergoes two-fold increase in the narrow temperature interval corresponding to the domain of beta-phase of uranium. The increase is followed by abrupt, factor of 3-4, strength drop when the initial state of the tested material is gamma-uranium. Such strength behavior explains the uranium susceptibility to adiabatic shear banding. The spall strength of both the alloys is characterized by similar temperature variations. The strength mechanism (phonon viscosity) acting in gamma-phase of pure uranium seems inherited from its alpha-structure while the strength of beta-uranium is controlled by high resistance to shearing characteristic for material having the structure of intermetallic sigma-phase.

  9. Estimates of uranium content and radon flux for uranium mine dumps based on borehole radioactivity logs. Topical report

    Microsoft Academic Search

    Riedel

    1980-01-01

    In exploratory drilling to locate uranium deposits, borehole logs of gamma radiation from naturally radioactive elements are used to indicate the presence of uranium and the concentrations in which it is found at various depths. This report describes a method of using borehole log data to estimate uranium concentrations in the rock surrounding or overlying uranium deposits and to predict

  10. Chemistry of actinide elements: some aspects of the solvent extraction of uranium(IV) and uranium(VI)

    Microsoft Academic Search

    Pai

    1970-01-01

    Thesis. Studies on some aspects of solvent extraction of uranium(IV) ; and uranium(VI) are reported. The investigation is described in two parts. The ; first part deals with the determination of stability constants of nitrate and ; sulfate complexes of uranium(IV) by solvent extraction. Uranium(IV) was ; extracted from nitric and sulfuric acid solutions by 20% benzene solution of ;

  11. Simplifying strong electronic correlations in uranium: Localized uranium heavy-fermion UM2Zn20 (M=Co,Rh) compounds

    E-print Network

    Lawrence, Jon

    into their underlying physics. Uranium-based heavy-fermion HF metals share charac- teristic behavior with rareSimplifying strong electronic correlations in uranium: Localized uranium heavy-fermion UM2Zn20 (M-field effects corroborate an ionic-like uranium electronic configura- tion in UM2Zn20. DOI: 10.1103/PhysRevB.78

  12. Ion exchange process using resins of high loading capacity, high chloride tolerance and rapid elution for uranium recovery

    Microsoft Academic Search

    Yan

    1983-01-01

    The present invention relates to a process for effectively recovering uranium from dilute solutions, particularly alkaline carbonate leachates from an in-situ leaching process. The uranium complexes are made unstable by adjusting the pH of the leachate to about 6.5 using mineral acids or carbon dioxide. The solution is then passed over ion exchanger resin which induces percipitation of uranium. This

  13. Deliberate overdose of uranium: toxicity and treatment.

    PubMed

    Pavlakis, N; Pollock, C A; McLean, G; Bartrop, R

    1996-01-01

    A case is described of deliberate ingestion of 15 g of uranium acetate which resulted in acute renal failure requiring dialytic therapy for 2 weeks, refractory anaemia, rhabdomyolysis, myocarditis, liver dysfunction with a disproportionate coagulopathy and paralytic ileus. Despite significant elevations in plasma uranium levels, treatment with both calcium EDTA and calcium DTPA were ineffective in promoting uranium excretion. Six months later the initial significant renal impairment exists with a persistent incomplete Fanconi syndrome. Future options for management of this unusual cause of acute renal failure are discussed. PMID:8684547

  14. Uranium nitride behavior at thermionic temperatures

    NASA Technical Reports Server (NTRS)

    Phillips, W. M.

    1973-01-01

    The feasibility of using uranium nitride for in-core thermionic applications was evaluated in electrically heated thermal gradient tests and in flat plate thermionic converters. These tests indicated that grain boundary penetration of uranium nitride into both tungsten and rhenium will occur under thermal gradient conditions. In the case of the tungsten thermionic converter, this led to grain boundary rupture of the emitter and almost total loss of electrical output from the converter. It appears that uranium nitride is unsuitable for thermionic applications at the 2000 K temperatures used in these tests.

  15. Controlled potential coulometric determination of uranium and neptunium in uranium-neptunium alloys.

    PubMed

    Plock, C E; Polkinghorne, W S

    1967-11-01

    A controlled potential coulometric titration method has been developed for the determination of neptunium and uranium in the presence of each other. The recovery of a neptunium standard in the presence of uranium was 100.02% with a relative standard deviation of 0.13%, and the recovery of a uranium standard in the presence of neptunium was 100.03% with a relative standard deviation of 0.13%. PMID:18960240

  16. Theoretical study on the alloying behavior of ?-uranium metal: ?-uranium alloy with 3d transition metals

    Microsoft Academic Search

    Masayoshi Kurihara; Masaru Hirata; Rika Sekine; Jun Onoe; Hirohide Nakamatsu

    2004-01-01

    We have investigated the alloying behavior of ?-uranium with 3d transition metals (TMs) using the relativistic discrete-variational Dirac–Fock–Slater (DV-DFS) method. The d-orbital energy (Md) as an alloying parameter well reproduces the alloying behavior of ?-uranium metal with TMs: (1) in the case of a large Md value (Ti, V, Cr), the solubility of these TM elements in ?-uranium becomes large;

  17. Assessing the renal toxicity of Capstone depleted uranium oxides and other uranium compounds.

    PubMed

    Roszell, Laurie E; Hahn, Fletcher F; Lee, Robyn B; Parkhurst, Mary Ann

    2009-03-01

    The primary target for uranium toxicity is the kidney. The most frequently used guideline for uranium kidney burdens is the International Commission on Radiological Protection value of 3 microg U g(-1) kidney, a value that is based largely upon chronic studies in animals. In the present effort, a risk model equation was developed to assess potential outcomes of acute uranium exposure. Twenty-seven previously published case studies in which workers were acutely exposed to soluble compounds of uranium (as a result of workplace accidents) were analyzed. Kidney burdens of uranium for these individuals were determined based on uranium in the urine, and correlated with health effects observed over a period of up to 38 years. Based upon the severity of health effects, each individual was assigned a score (- to +++) and then placed into a Renal Effects Group (REG). A discriminant analysis was used to build a model equation to predict the REG based on the amount of uranium in the kidneys. The model equation was able to predict the REG with 85% accuracy. The risk model was used to predict the REG for soldiers exposed to depleted uranium as a result of friendly fire incidents during the 1991 Gulf War. This model equation can also be used to predict the REG of new cases in which acute exposures to uranium have occurred. PMID:19204490

  18. Uranium plutonium oxide fuels. [LMFBR

    SciTech Connect

    Cox, C.M.; Leggett, R.D.; Weber, E.T.

    1981-01-01

    Uranium plutonium oxide is the principal fuel material for liquid metal fast breeder reactors (LMFBR's) throughout the world. Development of this material has been a reasonably straightforward evolution from the UO/sub 2/ used routinely in the light water reactor (LWR's); but, because of the lower neutron capture cross sections and much lower coolant pressures in the sodium cooled LMFBR's, the fuel is operated to much higher discharge exposures than that of a LWR. A typical LMFBR fuel assembly is shown. Depending on the required power output and the configuration of the reactor, some 70 to 400 such fuel assemblies are clustered to form the core. There is a wide variation in cross section and length of the assemblies where the increasing size reflects a chronological increase in plant size and power output as well as considerations of decreasing the net fuel cycle cost. Design and performance characteristics are described.

  19. Energy spectrum of sputtered uranium

    NASA Technical Reports Server (NTRS)

    Weller, R. A.; Tombrello, T. A.

    1977-01-01

    The fission track technique for detecting uranium 235 was used in conjunction with a mechanical time-of-flight spectrometer to measure the energy spectrum in the region 1 eV to 1 keV of material sputtered from a 93% enriched U-235 foil by 80 keV Ar-40(+) ions. The spectrum was found to exhibit a peak in the region 2-4 eV and to decrease approximately as E to the -1.77 power for E is approximately greater than 100 eV. The design, construction and resolution of the mechanical spectrometer are discussed and comparisons are made between the data and the predictions of the ramdom collision cascade model of sputtering.

  20. Investigation of Trace Uranium in Biological Matrices

    E-print Network

    Miller, James Christopher

    2013-05-31

    A system for the analysis of urine bioassay samples for the purpose of inversely investigating an unknown exposure to uranium has been developed. This technique involves the use of a thin flow electrochemical cell in conjunction with an anodized...

  1. Process for reducing beta activity in uranium

    DOEpatents

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

    1985-04-11

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

  2. Investigation of Trace Uranium in Biological Matrices 

    E-print Network

    Miller, James Christopher

    2013-05-31

    A system for the analysis of urine bioassay samples for the purpose of inversely investigating an unknown exposure to uranium has been developed. This technique involves the use of a thin flow electrochemical cell in conjunction with an anodized...

  3. Lung cancer among Navajo uranium miners

    SciTech Connect

    Gottlieb, L.S.; Husen, L.A.

    1982-04-01

    Lung cancer has been a rare disease among the Indians of the southwestern United States. However, the advent of uranium mining in the area has been associated with an increased incidence of lung cancer among Navajo uranium miners. This study centers on Navajo men with lung cancer who were admitted to the hospital from February 1965 to May 1979. Of a total of 17 patients with lung cancer, 16 were uranium miners, and one was a nonminer. The mean value of cumulative radon exposure for this group was 1139.5 working level months (WLMs). The predominant cancer type was the small cell undifferentiated category (62.5 percent). The low frequency of cigarette smoking in this group supports the view that radiation is the primary cause of lung cancer among uranium miners and that cigarette smoking acts as a promoting agent.

  4. The alloy system uranium-titanium-zirconium

    Microsoft Academic Search

    B. Howlett

    1959-01-01

    The uranium-titanium-zirconium system in the composition range to 40 ; at.% titanium, 70 at.% zirconium is reported in nine isothermal sections between ; 575 deg and 1000 deg C. The principal features of the alloys are discussed. ; (auth);

  5. Swelling of Uranium Alloys at High Exposures

    SciTech Connect

    McDonell, W.R.

    2001-03-26

    This reports summarizes the results of postirradiation examinations of a series of unrestrained dilute uranium alloy specimens irradiated to exposures up to 13,000 MWD/T in NaK-containing stainless steel capsules.

  6. Compatibility of buffered uranium carbides with tungsten.

    NASA Technical Reports Server (NTRS)

    Phillips, W. M.

    1971-01-01

    Results of compatibility tests between tungsten and hyperstoichiometric uranium carbide alloys run at 1800 C for 1000 and 2500 hours. These tests compared tungsten-buffered uranium carbide with tungsten-buffered uranium-zirconium carbide. The zirconium carbide addition appeared to widen the homogeneity range of the uranium carbide, making additional carbon available for reaction. Reaction layers could be formed by either of two diffusion paths, one producing UWC2, while the second resulted in the formation of W2C. UWC2 acts as a diffusion barrier for carbon and slows the growth of the reaction layer with time, while carbon diffusion is relatively rapid in W2C, allowing equilibrium to be reached in less than 2500 hours at a temperature of 1800 C.

  7. Biosorption of uranium by human black hair.

    PubMed

    Saini, Amardeep Singh; Melo, Jose Savio

    2015-04-01

    Naturally available low cost materials have gained importance as effective alternative to conventional sorbents for the removal of metal ions from water. The present study describes the use of black hair waste as a sorbent for the removal of uranium ions from an aqueous medium. Alkali treatment of the biomass resulted in a significant increase in its uptake capacity. The optimum pH and contact time for uranium removal were 4.5 and 2 h respectively. It was observed that the experimental data fits well in Ho's pseudo-second order kinetic model. Binding of uranium to the biomass was confirmed using FT-IR spectroscopy. Thus, the present study could demonstrate the utility of human black hair to remove uranium from aqueous medium. PMID:25626175

  8. Regularities of spatial association of major endogenous uranium deposits and kimberlitic dykes in the uranium ore regions of the Ukrainian Shield

    NASA Astrophysics Data System (ADS)

    Kalashnyk, Anna

    2015-04-01

    During exploration works we discovered the spatial association and proximity time formation of kimberlite dykes (ages are 1,815 and 1,900 Ga for phlogopite) and major industrial uranium deposits in carbonate-sodium metasomatites (age of the main uranium ore of an albititic formation is 1,85-1,70 Ga according to U-Pb method) in Kirovogradsky, Krivorozhsky and Alekseevsko-Lysogorskiy uranium ore regions of the Ukrainian Shield (UkrSh) [1]. In kimberlites of Kirovogradsky ore region uranium content reaches 18-20 g/t. Carbon dioxide is a major component in the formation of hydrothermal uranium deposits and the formation of the sodium in the process of generating the spectrum of alkaline ultrabasic magmas in the range from picritic to kimberlite and this is the connection between these disparate geochemical processes. For industrial uranium deposits in carbonate-sodium metasomatitics of the Kirovogradsky and Krivorozhsky uranium ore regions are characteristic of uranyl carbonate introduction of uranium, which causes correlation between CO2 content and U in range of "poor - ordinary - rich" uranium ore. In productive areas of uranium-ore fields of the Kirovogradsky ore region for phlogopite-carbonate veinlets of uranium ore albitites deep ?13C values (from -7.9 to -6.9o/oo) are characteristic. Isotope-geochemical investigation of albitites from Novokonstantynovskoe, Dokuchaevskoe, Partyzanskoe uranium deposits allowed obtaining direct evidence of the involvement of mantle material during formation of uranium albitites in Kirovogradsky ore region [2]. Petrological characteristics of kimberlites from uranium ore regions of the UkrSh (presence of nodules of dunite and harzburgite garnet in kimberlites, diamonds of peridotite paragenesis, chemical composition of indicator minerals of kimberlite, in particular Gruzskoy areas pyropes (Cr2O3 = 6,1-7,1%, MgO = 19,33-20,01%, CaO = 4,14-4,38 %, the content of knorringite component of most grains > 50mol%), chromites (Cr2O3 = 45,32-62,17%, MgO = 7,3-12,5%) allow us to estimate the depth of generation of kimberlite magmas more than 170-200 km. Ilmenites show two groups according to MgO, Cr2O3 and TiO2 content. Reconstructions of the mantle sections show also two intervals of pressures divided at 4.5 GPa, the upper part is highly metasomatized This high degree metasomatism is determined for almost all mantle columns. It is suggested that large-scale of uranium-bearing mantle fluids may be associated with the ancient degasation during the subduction which is highly enriched in U component . Analysis of the reasons for the marked association kimberlitic dykes and major industrial uranium deposits in carbonate-sodium metasomatic in the UkrSh led to the conclusion that hydrothermal uranium deposits are confined to the supply mantle fluid systems of mantle fault zones exercising brings sodium carbonate solutions enriched uranium from mantle sources. References: 1. Kalashnik A.A. New prognostic-evaluation criteria in technology prognosis of forming industrial endogenous uranium deposits of the Ukrainian Shield, 2014. Scientific proceedings of UkrSGRI, ? 2, p. 27-54 (in Russian) 2. Stepanjuk L.M., Bondarenko S.V., Somka V.O. and other, 2012. Source of uranium and uranium-bearing sodium albitites for example of Dokuchaievskogo field of the Ingulsky megablock of the UkrSh: Abstracts of scientific conference "Theoretical issues and research practice metasomatic rocks and ores" (Kyiv, 14-16 March 2012), IGMOF, p.78-80. (in Ukrainian)

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

    SciTech Connect

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

    2013-02-01

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

  10. Empirical modeling of uranium nitride fuels

    E-print Network

    Brozak, Daniel Edward

    1987-01-01

    EMPIRICAL MODELING OF URANIUM NITRIDE FUELS A Thesis by DANIEL EDWARD BROZAK Submitted to the Cn aduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE December 1987 Major... Subject: Nuclear Engineering EMPIRICAL MODELING OF URANIUM NITRIDE FUELS A Thesis by DANIEL EDWARD BROZAK Approved as to style and content by: K. L. Peddicord (Chair of Committee) K. L. Peddkcord (Head of the Department) . A. Hassan (Member...

  11. The ultimate disposition of depleted uranium

    SciTech Connect

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

    1991-12-31

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

  12. Simple Method for Depleted Uranium Determination

    Microsoft Academic Search

    Istvan Bikit; Jaroslav Slivka; Dusan Mrdja; Natasa Zikic-Todorovic; Sofija Curcic; Ester Varga; Miroslav Veskovic; Ljiljana Conkic

    2003-01-01

    When the issue of depleted uranium (DU) presence in the environment emerged, methods for analytical discrimination of DU against natural uranium should be developed. We present here a simple gamma-spectrometric method, based on the 238U-226Ra activity (non) equilibrium. The detection limit of the method for DU is of the order of magnitude of 10 Bq\\/kg (for about 50 ks counting),

  13. Removal of uranium from aqueous HF solutions

    Microsoft Academic Search

    Howard Pulley; Steven F. Seltzer

    1980-01-01

    This invention is a simple and effective method for removing uranium from aqueous HF solutions containing trace quantities of the same. The method comprises contacting the solution with particulate calcium fluoride to form uranium-bearing particulates, permitting the particulates to settle, and separting the solution from the settled particulates. The CaF.sub.2 is selected to have a nitrogen surface area in a

  14. Extraction of uranium values from phosphoric acid

    Microsoft Academic Search

    T. Largman; S. Sifniades; A. A. Tunick

    1982-01-01

    Aqueous phosphoric acid solutions containing uranium values are contacted with an organic solution of a mixture of organophosphorus compounds produced from a carboxylic acid and pcl3 in the presence of water or from corresponding acid halides or anhydrides and phosphorous acid to extract the uranium values. The organophorus compounds generally include an alkane-1,1,2triphosphonic acid or a 1-hydroxy-1,1-alkanediphosphonic acid or both,

  15. Removal of uranium from aqueous HF solutions

    Microsoft Academic Search

    H. Pulley; S. F. Seltzer

    1980-01-01

    This invention is a simple and effective method for removing uranium from aqueous HF solutions containing trace quantities of the same. The method comprises contacting the solution with particulate calcium fluoride to form uranium-bearing particulates, permitting the particulates to settle, and separating the solution from the settled particulates. The CaF2 is selected to have a nitrogen surface area in a

  16. Material property correlations for uranium mononitride 

    E-print Network

    Hayes, Steven Lowe

    1989-01-01

    MATERIAL PROPERTY CORRELATIONS FOR URANIUM MONONITRIDE A Thesis by STEVEN LOWE HAYES Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August... 1989 Major Subject: Nuclear Engineering MATERIAL PROPERTY CORRELATIONS FOR URANIUM MONONITRIDE A Thesis by STEVEN LOWE HAYES Approved as to style and content by: K. L. Peddicord (Chair of Committee) R. R. Hart (Member) C. P. Burger (Member...

  17. Uranium in saline lakes of Northwestern Mongolia

    Microsoft Academic Search

    V. P. Isupov; A. G. Vladimirov; N. Z. Lyakhov; S. L. Shvartsev; S. Ariunbileg; M. N. Kolpakova; S. S. Shatskaya; L. E. Chupakhina; L. V. Kuibida; E. N. Moroz

    2011-01-01

    Analysis of major- and trace-element compositions of water in hypersaline soda closed basin lakes of Northwestern Mongolia\\u000a and Chuya basin (Gorny Altai) shows high enrichment in 238U (up to 1 mg\\/l). Proceeding from new data, uranium accumulation in water has been attributed to (i) location of the lakes\\u000a and their watersheds in potential provinces of U-bearing rocks and (ii) uranium

  18. Blending UNH streams of different uranium enrichments

    Microsoft Academic Search

    1958-01-01

    The cost and feasibility of blending UNH streams of different uranium enrichments at HAPO was evaluated on a preliminary basis. Cases studied were blending 37.5% enriched UNH with depleted E metal UNH to yield a 0.947% enriched end product, and blending depleted E metal UNH with the depleted natural uranium to yield 0.7115% enriched end product. A reasonable degree of

  19. Depleted uranium: A DOE management guide

    SciTech Connect

    NONE

    1995-10-01

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

  20. BIOREMEDIATION OF URANIUM CONTAMINATED SOILS AND WASTES.

    SciTech Connect

    FRANCIS,A.J.

    1998-09-17

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

  1. Environmental regulation of uranium mining in Australia

    Microsoft Academic Search

    Peter Waggitt

    Uranium mining has been taking place in Australia more or less continuously since the late 1930s but it really only came to the fore after 1945. Environmental protection legislation did not become established until 1976. As a consequence the environmental management of many early uranium mines was virtually non-existent and a number of adverse environmental impacts were recorded. p]The development

  2. Remediation of the Former Uranium Mine Ranstad

    Microsoft Academic Search

    B. Sundblad

    \\u000a The open-pit uranium mine Ranstad in southwestern Sweden (see Figure 1) was developed as a part of the Swedish Nuclear Power\\u000a Programme. Uranium was extracted by percolation leaching with sulfuric acid from alum shale, which has a grade of about 300\\u000a g\\/t [1]. The plant was operated from 1965 to 1969. A total of 1.5 Mtons of alum shale was

  3. Uranium Exposures in a Community near a Uranium Processing Facility: Relationship with Hypertension and Hematologic Markers

    PubMed Central

    Wagner, Sara E.; Burch, James B.; Bottai, Matteo; Pinney, Susan M.; Puett, Robin; Porter, Dwayne; Vena, John E.; Hébert, James R.

    2010-01-01

    Background Environmental uranium exposure originating as a byproduct of uranium processing can impact human health. The Fernald Feed Materials Production Center functioned as a uranium processing facility from 1951 to 1989, and potential health effects among residents living near this plant were investigated via the Fernald Medical Monitoring Program (FMMP). Methods Data from 8,216 adult FMMP participants were used to test the hypothesis that elevated uranium exposure was associated with indicators of hypertension or changes in hematologic parameters at entry into the program. A cumulative uranium exposure estimate, developed by FMMP investigators, was used to classify exposure. Systolic and diastolic blood pressure and physician diagnoses were used to assess hypertension; and red blood cells, platelets, and white blood cell differential counts were used to characterize hematology. The relationship between uranium exposure and hypertension or hematologic parameters was evaluated using generalized linear models and quantile regression for continuous outcomes, and logistic regression or ordinal logistic regression for categorical outcomes, after adjustment for potential confounding factors. Results Of 8,216 adult FMMP participants 4,187 (51%) had low cumulative uranium exposure, 1,273 (15%) had moderate exposure, and 2,756 (34%) were in the high (>0.50 Sievert) cumulative lifetime uranium exposure category. Participants with elevated uranium exposure had decreased white blood cell and lymphocyte counts and increased eosinophil counts. Female participants with higher uranium exposures had elevated systolic blood pressure compared to women with lower exposures. However, no exposure-related changes were observed in diastolic blood pressure or hypertension diagnoses among female or male participants. Conclusions Results from this investigation suggest that residents in the vicinity of the Fernald plant with elevated exposure to uranium primarily via inhalation exhibited decreases in white blood cell counts, and small, though statistically significant, gender-specific alterations in systolic blood pressure at entry into the FMMP. PMID:20889151

  4. DURABILITY OF DEPLETED URANIUM AGGREGATES (DUAGG) IN DUCRETE SHIELDING APPLICATIONS

    SciTech Connect

    Mattus, Catherine H.; Dole, Leslie R.

    2003-02-27

    The depleted uranium (DU) inventory in the United States exceeds 500,000 metric tonnes. To evaluate the possibilities for reuse of this stockpile of DU, the U.S. Department of Energy (DOE) has created a research and development program to address the disposition of its DU(1). One potential use for this stockpile material is in the fabrication of nuclear shielding casks for the storage, transport, and disposal of spent nuclear fuels. The use of the DU-based shielding would reduce the size and weight of the casks while allowing a level of protection from neutrons and gamma rays comparable to that afforded by steel and concrete. DUAGG (depleted uranium aggregate) is formed of depleted uranium dioxide (DUO2) sintered with a synthetic-basalt-based binder. This study was designed to investigate possible deleterious reactions that could occur between the cement paste and the DUAGG. After 13 months of exposure to a cement pore solution, no deleterious expansive mineral phases were observed to form either with the DUO2 or with the simulated-basalt sintering phases. In the early stages of these exposure tests, Oak Ridge National Laboratory preliminary results confirm that the surface reactions of this aggregate proceed more slowly than expected. This finding may indicate that DUAGG/DUCRETE (depleted uranium concrete) casks could have service lives sufficient to meet the projected needs of DOE and the commercial nuclear power industry.

  5. Microbial transformation of uranium in wastes

    SciTech Connect

    Francis, A.J.; Dodge, C.J.; Gillow, J.B.; Cline, J.E. (Brookhaven National Lab., Upton, NY (USA); Oak Ridge Y-12 Plant, TN (USA))

    1989-01-01

    Contamination of soils, water, and sediments by radionuclides and toxic metals from the disposal of uranium processing wastes is a major national concern. Although much is known about the physico- chemical aspects of U, we have little information on the effects of aerobic and anaerobic microbial activities on the mobilization or immobilization of U and other toxic metals in mixed wastes. In order to understand the mechanisms of microbial transformations of uranium, we examined a contaminated pond sediment and a sludge sample from the uranium processing facility at Y-12 Plant, Oak Ridge, TN. The uranium concentration in the sediment and sludge samples was 923 and 3080 ug/g dry wt, respectively. In addition to U, the sediment and sludge samples contained high levels of toxic metals such as Cd, Cr, Cu, Hg, Pb, Ni, and Zn. The association of uranium with the various mineral fractions of the sediment and sludge was determined by selective chemical extraction techniques. Uranium was associated to varying degrees with the exchangeable carbonate, iron oxide, organic, and inert fractions in both samples. Initial results in samples amended with carbon and nitrogen indicate immobilization of U due to enhanced indigenous microbial activity under anaerobic conditions. 23 refs., 4 figs., 5 tabs.

  6. The United States Uranium Industry, 1993

    SciTech Connect

    Chenoweth, W.L.

    1993-08-01

    Low prices and foreign competition continue to plague the United States uranium industry. For eight years (1984-1991) the Secretary of Energy has declared the industry to be nonviable. A similar declaration is expected late in 1993 for 1992. Surface drilling for uranium in 1993 is expected to be about 1 million ft., because deposits are developed prior to mining. Drilling for claim assessment purposes has ceased due to changes in the mining law. All conventional mining and milling in the United States ceased in early 1992 when the last open-pit mine closed. Underground mining ceased in late 1990. Current uranium production is from solution mining (in-situ leaching) in Wyoming, Texas, and Nebraska. Uranium is recovered from Florida phosphate rock processed in Louisiana and from mine water in New Mexico. Uranium concentrate production in 1993 is expected to be about 5 million lbs U[sub 3]O[sub 8]. The United States has large reserves of uranium, but a significant price increase is needed for the industry to rebound.

  7. Permitting and licensing new uranium recovery facilities

    SciTech Connect

    Rehmann, M. [Tetra Tech EM, Inc., Breckenridge, Colorado (United States); Sweeney, K. [National Mining Association, Washington, DC (United States); Pugsley, C. [Thompson and Simmons, Washington DC (United States)

    2007-07-01

    With the nuclear renaissance, the uranium mining industry has undergone a dramatic renaissance, as well. This was evidenced with the 2006 National Mining Association (NMA)/Nuclear Regulatory Commission (NRC) workshop drawing its largest attendance ever, with more than 180 attendees representing both established, as well as many new junior firms. And the meeting focused, not on site closure - but on the growing industry and plans for permitting new uranium recovery facilities. With this, the program provided overviews of the programs for permitting and licensing new uranium mines, from both the State and Federal perspectives. A subsequent one-day licensing workshop presented in February 2007 by NRC at its headquarters in Rockville, Maryland drew a crowd of experienced and first-time license applicants. Modern uranium mining is both safer and more environmentally protective than past practices - due largely to the industry's maturing and continuous efforts to improve. This paper will look at the new generation of uranium mining and recovery facilities that are developing in the US, and focus primarily on US permitting and licensing requirements and trends. Understanding these trends is essential to ensuring a vibrant US uranium recovery industry; assured supplies of this important fuel for our energy and the US economy; and environmental protection. (authors)

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

    SciTech Connect

    NONE

    1995-07-05

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

  9. Uranium ores and depleted uranium in the environment, with a reference to uranium in the biosphere from the Erzgebirge\\/Sachsen, Germany

    Microsoft Academic Search

    A. Meinrath; P. Schneider; G. Meinrath

    2003-01-01

    The Erzgebirge (‘Ore Mountains’) area in the eastern part of Germany was a major source of uranium for Soviet nuclear programs between 1945 and 1989. During this time, the former German Democratic Republic became the third largest uranium producer in the world. The high abundance of uranium in the geological formations of the Erzgebirge are mirrored in the discovery of

  10. Effect of uranium (VI) on two sulphate-reducing bacteria cultures from a uranium mine site

    Microsoft Academic Search

    Mónica Martins; Maria Leonor Faleiro; Sandra Chaves; Rogério Tenreiro; Maria Clara Costa

    2010-01-01

    This work was conducted to assess the impact of uranium (VI) on sulphate-reducing bacteria (SRB) communities obtained from environmental samples collected on the Portuguese uranium mining area of Urgeiriça. Culture U was obtained from a sediment, while culture W was obtained from sludge from the wetland of that mine. Temperature gradient gel electrophoresis (TGGE) was used to monitor community changes

  11. Assessing the Renal Toxicity of Capstone Depleted Uranium Oxides and Other Uranium Compounds

    Microsoft Academic Search

    Laurie E. Roszell; Fletcher F. Hahn; Robyn B. Lee; MaryAnn Parkhurst

    2009-01-01

    The primary target for uranium toxicity is the kidney. The most frequently used guideline for uranium kidney burdens is the International Commission on Radiation Protection (ICRP) value of 3 µg U\\/g kidney, a value that is based largely upon chronic studies in animals. In the present effort, we have developed a risk model equation to assess potential outcomes of acute

  12. Uptake and mobility of uranium in black oaks: implications for biomonitoring depleted uranium-contaminated groundwater

    Microsoft Academic Search

    Jesse D Edmands; Daniel J Brabander; Drew S Coleman

    2001-01-01

    In a preliminary study, the uptake and the mobility of uranium (U) by black oak trees (Quercus velutina) were assessed by measuring the isotopic composition of tree rings in two mature oak trees in a heavy metal contaminated bog in Concord, MA. The bog is adjacent to a nuclear industrial facility that has been processing depleted uranium (DU) since 1959.

  13. Low-temperature conversion of uranium oxides to uranium hexafluoride using dioxygen difluoride

    SciTech Connect

    Asprey, L.B.; Kinkead, S.A.: Eller, P.G.

    1986-04-01

    The fluorination of uranium oxides to volatile uranium hexafluoride with elemental fluorine requires temperatures of 300 to 400/sup 0/C to achieve appreciable conversion rates. Until now no gaseous agent has been reported that will efficiently carry out this technologically important transformation at low temperature. In this paper, the authors report such a reaction using dioxygen difluoride at room temperature.

  14. Low-temperature conversion of uranium oxides to uranium hexafluoride using dioxygen difluoride

    Microsoft Academic Search

    L. B. Asprey; Kinkead

    1986-01-01

    The fluorination of uranium oxides to volatile uranium hexafluoride with elemental fluorine requires temperatures of 300 to 400°C to achieve appreciable conversion rates. Until now no gaseous agent has been reported that will efficiently carry out this technologically important transformation at low temperature. In this paper, the authors report such a reaction using dioxygen difluoride at room temperature.

  15. Mass spectrographic determination of hydrogen thermally evolved from uranium and uranium alloys

    Microsoft Academic Search

    G. L. Powell; J. B. Condon

    1973-01-01

    A hot-extraction, high-vacuum technique using mass-spectrographic ; detection has been used to determine the hydrogen content in uranium metal and ; uranium alloys. The time dependence of the evolution of hydrogen from the bulk ; metal and that from surface contamination was sufficiently different to resolve ; these two components. During the transient temperature portion of the analysis ; the

  16. Speciation of uranium in compartments of living cells.

    PubMed

    Geipel, Gerhard; Viehweger, Katrin

    2015-06-01

    Depleted uranium used as ammunition corrodes in the environment forming mineral phases and then dissolved uranium species like uranium carbonates (Schimmack et al., in Radiat Environ Biophys 46:221-227, 2007) and hydroxides. These hydroxide species were contacted with plant cells (canola). After 24 h contact time the cells were fractionated and the uranium speciation in the fraction was determined by time resolved laser-induced fluorescence spectroscopy at room temperature as well at 150 K. It could be shown that the uranium speciation in the fractions is different to that in the nutrient solution. Comparison of the emission bands with literature data allows assignment of the uranium binding forms. PMID:25724950

  17. Selected uranium and uranium-thorium occurrences in New Hampshire

    USGS Publications Warehouse

    Bothner, W.A.

    1978-01-01

    Secondary uranium mineralization occurs in a northwest-trending fracture zone in the Devonian Concord Granite in recent rock cuts along Interstate Highway 89 near New London, New Hampshire. A detailed plane table map of this occurrence was prepared. Traverses using total gamma ray scintillometers throughout the pluton of Concord Granite identified two additional areas in which very small amounts of secondary mineralization occurs in the marginal zones of the body. All three areas lie along the same northwest trend. A ground radiometry survey of a large part of the Jurassic White Mountain batholith was conducted. Emphasis was placed on those areas from which earlier sampling by Butler (1975) had been done. No unusual geological characteristics were apparent around sample localities from which anomalous U and Th had been reported.. The results of this survey confirm previous conclusions that the red, coarse-grained, biotite granite phase of the Conway Granite is more radioactive than other phases of the Conway Granite or other rock types of the White Mountain Plutonic-Volcanic Series. Aplites associated with the Conway Granite were found .generally to be as radioactive as the red Conway Granite.

  18. ZDC Effective Cross Section for Run 12 Uranium-Uranium Collisions in RHIC

    E-print Network

    Drees, Angelika

    2013-01-01

    An accurate calibration of the luminosity measurement of the 2012 Uranium-Uranium RHIC run at 96 GeV per beam is of the greatest importance in order to measure the total uranium-uranium cross section with a reasonably small error bar. During the run, which lasted from April 20th to May 15th 2012, three vernier scans per experiment were performed. Beam intensities of up to 3.4 10$^{10}$ Uranium ions in one ring were successfully accelerated to flattop at $\\gamma = 103.48$ corresponding to 96 GeV/beam. The desired model $\\beta^*$ value was 0.7 m in the two low beta Interaction Points IP6 and IP8. With these beam parameters interaction rates of up to 15 kHz were achieved. This note presents the data associated with the vernier scans, and discusses the results and systematic effects.

  19. An evaluation and revision of the gravimetric determination of uranium in uranium hexafluoride

    SciTech Connect

    Vita, O.A.; Trivisonno, C.F.; Shoaf, R.E.

    1982-01-26

    An evaluation of the indirect gravimetric determination of uranium in uranium hexafluoride has been made, and the accuracy has been established by comparison to a direct titration of uranium using potassium dichromate (SRM-136c). From this study the gravimetric method has been revised to increase accuracy. The revised method is biased less than 0.01 percent low as compared to 0.02 percent with the unrevised method. It was found that the gravimetric factor must be based on the stoichiometry of the U/sub 3/O/sub 8/ which varies with pyrohydrolysis conditions. The low bias was caused by volatilization loss of uranium as uranium hexafluoride during pyrohydrolysis and very small errors in the determination of the sample weight. Because of the volatilization loss the use of a bias correction factor with the revised method is justified. 5 refs., 7 tabs.

  20. Microbial Uranium Immobilization Independent of Nitrate Reduction

    SciTech Connect

    Madden, Andrew [ORNL; Smith, April [Florida State University; Balkwill, Dr. David [Florida State University; Fagan, Lisa Anne [ORNL; Phelps, Tommy Joe [ORNL

    2007-01-01

    At many uranium processing and handling facilities, including sites in the U.S. Department of Energy (DOE) complex, high levels of nitrate are present as co-contamination with uranium in groundwater. The daunting prospect of complete nitrate removal prior to the reduction of uranium provides a strong incentive to explore bioremediation strategies that allow for uranium bioreduction and stabilization in the presence of nitrate. Typical in-situ strategies involving the stimulation of metal-reducing bacteria are hindered by low pH environments at this study site and require that the persistent nitrate must first and continuously be removed or transformed prior to uranium being a preferred electron acceptor. This project investigates the possibility of stimulating nitrate-indifferent, pH-tolerant microorganisms to achieve bioreduction of U(VI) despite nitrate persistence. Successful enrichments from U-contaminated sediments demonstrated nearly complete reduction of uranium with very little loss of nitrate from pH 4.9-5.6 using methanol or glycerol as a carbon source. Higher pH enrichments also demonstrated similar U reduction capacity with 5-30% nitrate loss within one week. Bacterial 16S rRNA genes were amplified from uranium-reducing enrichments (pH 5.7-6.7) and sequenced. Phylogenetic analyses classified the clone sequences into four distinct clusters. Data from sequencing and T-RFLP profiles indicated that the majority of the microorganisms stimulated by these enrichment conditions consisted of low G+C Gram-positive bacteria most closely related to Clostridium and Clostridium-like organisms. This research demonstrates that the stimulation of a natural microbial community to immobilize U through bioreduction is possible without the removal of nitrate.

  1. The Renaissance of Non-Aqueous Uranium Chemistry.

    PubMed

    Liddle, Stephen T

    2015-07-20

    Prior to the year 2000, non-aqueous uranium chemistry mainly involved metallocene and classical alkyl, amide, or alkoxide compounds as well as established carbene, imido, and oxo derivatives. Since then, there has been a resurgence of the area, and dramatic developments of supporting ligands and multiply bonded ligand types, small-molecule activation, and magnetism have been reported. This Review 1)?introduces the reader to some of the specialist theories of the area, 2)?covers all-important starting materials, 3)?surveys contemporary ligand classes installed at uranium, including alkyl, aryl, arene, carbene, amide, imide, nitride, alkoxide, aryloxide, and oxo compounds, 4)?describes advances in the area of single-molecule magnetism, and 5)?summarizes the coordination and activation of small molecules, including carbon monoxide, carbon dioxide, nitric oxide, dinitrogen, white phosphorus, and alkanes. PMID:26079536

  2. Atomistic Properties of Y Uranium

    SciTech Connect

    Benjamin Beeler; Chaitanya Deo; Mmichael Baskes; Maria Okuniewski

    2012-02-01

    The properties of the body-centered cubic y phase of uranium (U) are calculated using atomistic simulations. First, a modified embedded-atom method interatomic potential is developed for the high temperature body-centered cubic (y) phase of U. This phase is stable only at high temperatures and is thus relatively inaccessible to first principles calculations and room temperature experiments. Using this potential, equilibrium volume and elastic constants are calculated at 0 K and found to be in close agreement with previous first principles calculations. Further, the melting point, heat capacity, enthalpy of fusion, thermal expansion and volume change upon melting are calculated and found to be in reasonable agreement with experiment. The low temperature mechanical instability of y U is correctly predicted and investigated as a function of pressure. The mechanical instability is suppressed at pressures greater than 17.2 GPa. The vacancy formation energy is analyzed as a function of pressure and shows a linear trend, allowing for the calculation of the extrapolated zero pressure vacancy formation energy. Finally, the self-defect formation energy is analyzed as a function of temperature. This is the first atomistic y calculation of U properties above 0 K with interatomic potentials.

  3. Uranium transformations in static microcosms.

    SciTech Connect

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

    2010-01-01

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

  4. Characterizing In Situ Uranium and Groundwater Flux

    NASA Astrophysics Data System (ADS)

    Cho, J.; Newman, M. A.; Stucker, V.; Peacock, A.; Ranville, J.; Cabaniss, S.; Hatfield, K.; Annable, M. D.; Klammler, H.; Perminova, I. V.

    2010-12-01

    The goal of this project is to develop a new sensor that incorporates the field-tested concepts of the passive flux meter to provide direct in situ measures of uranium and groundwater fluxes. The sensor uses two sorbents and resident tracers to measure uranium flux and specific discharge directly; but, sensor principles and design should also apply to fluxes of other radionuclides. Flux measurements will assist with obtaining field-scale quantification of subsurface processes affecting uranium transport (e.g., advection) and transformation (e.g., uranium attenuation) and further advance conceptual and computational models for field scale simulations. Project efforts will expand our current understanding of how field-scale spatial variations in uranium fluxes and those for salient electron donor/acceptors, and groundwater are coupled to spatial variations in measured microbial biomass/community composition, effective field-scale uranium mass balances, attenuation, and stability. The new sensor uses an anion exchange resin to measure uranium fluxes and activated carbon with resident tracers to measure water fluxes. Several anion-exchange resins including Dowex 21K and 21K XLT, Purolite A500, and Lewatit S6328 were tested as sorbents for capturing uranium on the sensor and Lewatit S6328 was determined to be the most effective over the widest pH range. Four branched alcohols proved useful as resident tracers for measuring groundwater flows using activated carbon for both laboratory and field conditions. The flux sensor was redesigned to prevent the discharge of tracers to the environment, and the new design was tested in laboratory box aquifers and the field. Geochemical modeling of equilibrium speciation using Visual Minteq and an up-to-date thermodynamic data base suggested Ca-tricarbonato-uranyl complexes predominate under field conditions, while calculated uranyl ion activities were sensitive to changes in pH, dissolved inorganic carbon (DIC) and alkaline earth metals. Initial field tests at the Rifle IFRC site were conducted to assess ambient groundwater and uranium fluxes, monitor microbial growth on the sensor during field deployment, and further resolve any unforeseen problems evolving from field deployment. Ten flux sensors were deployed in five wells for three weeks from mid-November to early December 2009. Observed water fluxes varied from 1.2 - 5.3 cm/d while uranium fluxes ranged from 0.01 - 2.2 ug/cm2d. Uranium and water flux variations corresponded closely with changes in lithology. Uranium fluxes were typically observed to increase with depth. Stochastic simulations were conducted to estimate the magnitude of uranium discharge over a 10.5 m2 transect. The mean discharge was approximately 52 mg/d with a narrow 90% confidence interval of ± 11%.

  5. REMOVAL OF URANIUM FROM DRINKING WATER BY CONVENTIONAL TREATMENT METHODS

    EPA Science Inventory

    The USEPA currently does not regulate uranium in drinking water but will be revising the radionuclide regulations during 1989 and will propose a maximum contaminant level for uranium. The paper presents treatment technology information on the effectiveness of conventional method...

  6. Prospects for the recovery of uranium from seawater

    E-print Network

    Best, F. R.

    1980-01-01

    A computer program entitled URPE (Uranium Recovery Performance and Economics) has been developed to simulate the engineering performance and provide an economic analysis O of a plant recovering uranium from seawater. The ...

  7. Reducing the environmental impact of uranium in-situ recovery

    Microsoft Academic Search

    Malcolm Dean Siegel; Ardyth Simmons

    2010-01-01

    This session will explore the current technical approaches to reducing the environmental effects of uranium ISR in comparison to the historical environmental impact of uranium mining to demonstrate advances in this controversial subject.

  8. Distribution of uranium in mice using the fission track technique

    NASA Astrophysics Data System (ADS)

    Yulin, Cheng; Junying, Lin; Jiong, Zhang; Guaofu, Liu; Liping, Zheng; Xiaoyu, Cheng; Xiuhong, Hao

    1992-09-01

    Four groups of mice were dissected at various time intervals from 0.5 to 144 hours after their intravenous injection of uranium. The uranium distribution and deposition in the tissues of kidney, lung, marrow, liver, heart, muscle and blood have been studied using the fission track technique (FTT). Our experimental results show that trace uranium is more likely to be deposited in kidneys and lungs than in marrow and liver. The presence of uranium in the blood is so transient that blood-uranium level cannot be used to estimate the degree of the storage of uranium in the body. However, the mice injected with high dose uranium die soon because the uranium poisons the heart severely.

  9. 10 CFR 39.49 - Uranium sinker bars.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    The licensee may use a uranium sinker bar in well logging applications only if it is legibly impressed with the words “CAUTION—RADIOACTIVE-DEPLETED URANIUM” and “NOTIFY CIVIL AUTHORITIES (or COMPANY NAME) IF FOUND.” [65 FR 20345, Apr. 17,...

  10. 10 CFR 39.49 - Uranium sinker bars.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    The licensee may use a uranium sinker bar in well logging applications only if it is legibly impressed with the words “CAUTION—RADIOACTIVE-DEPLETED URANIUM” and “NOTIFY CIVIL AUTHORITIES (or COMPANY NAME) IF FOUND.” [65 FR 20345, Apr. 17,...

  11. 10 CFR 39.49 - Uranium sinker bars.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    The licensee may use a uranium sinker bar in well logging applications only if it is legibly impressed with the words “CAUTION—RADIOACTIVE-DEPLETED URANIUM” and “NOTIFY CIVIL AUTHORITIES (or COMPANY NAME) IF FOUND.” [65 FR 20345, Apr. 17,...

  12. 10 CFR 39.49 - Uranium sinker bars.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    The licensee may use a uranium sinker bar in well logging applications only if it is legibly impressed with the words “CAUTION—RADIOACTIVE-DEPLETED URANIUM” and “NOTIFY CIVIL AUTHORITIES (or COMPANY NAME) IF FOUND.” [65 FR 20345, Apr. 17,...

  13. 10 CFR 39.49 - Uranium sinker bars.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    The licensee may use a uranium sinker bar in well logging applications only if it is legibly impressed with the words “CAUTION—RADIOACTIVE-DEPLETED URANIUM” and “NOTIFY CIVIL AUTHORITIES (or COMPANY NAME) IF FOUND.” [65 FR 20345, Apr. 17,...

  14. Calixarene cleansing formulation for uranium skin contamination.

    PubMed

    Phan, Guillaume; Semili, Naïma; Bouvier-Capely, Céline; Landon, Géraldine; Mekhloufi, Ghozlene; Huang, Nicolas; Rebière, François; Agarande, Michelle; Fattal, Elias

    2013-10-01

    An oil-in-water cleansing emulsion containing calixarene molecule, an actinide specific chelating agent, was formulated in order to improve the decontamination of uranium from the skin. Commonly commercialized cosmetic ingredients such as surfactants, mineral oil, or viscosifying agents were used in preparing the calixarene emulsion. The formulation was characterized in terms of size and apparent viscosity measurements and then was tested for its ability to limit uranyl ion permeation through excoriated pig-ear skin explants in 24-h penetration studies. Calixarene emulsion effectiveness was compared with two other reference treatments consisting of DTPA and EHBP solutions. Application of calixarene emulsion induced the highest decontamination effect with an 87% decrease in uranium diffusion flux. By contrast, EHBP and DTPA solutions only allowed a 50% and 55% reduction of uranium permeation, respectively, and had the same effect as a simple dilution of the contamination by pure water. Uranium diffusion decrease was attributed to uranyl ion-specific chelation by calixarene within the formulation, since no significant effect was obtained after application of the same emulsion without calixarene. Thus, calixarene cleansing emulsion could be considered as a promising treatment in case of accidental contamination of the skin by highly diffusible uranium compounds. PMID:23982616

  15. Removal of uranium from aqueous solutions by diatomite (Kieselguhr)

    Microsoft Academic Search

    S. Akyil; M. A. A. Aslani; U. Aytekin

    1999-01-01

    In this study, the removal of uranium from aqueous solutions by diatomite earth (Kieselguhr) fine particules has been investigated.\\u000a Diatomite earth is an important adsorbent material in chromatographic studies. Uranium adsorption capacity of four different\\u000a types of diatomite was determined. The adsorption of uranium on the chosen diatomite sample was examined as a function of\\u000a uranium concentration, solution pH, contact

  16. Uranium internal exposure evaluation based on urine assay data

    SciTech Connect

    Lawrence, J.N.P.

    1984-09-01

    The difficulties in assessing internal exposures to uranium from urine assay data are described. A simplified application of the ICRP-30 and ICRP Lung Model concepts to the estimation of uranium intake is presented. A discussion follows on the development of a computer code utilizing the ICRP-30-based uranium elimination model with the existing urine assay information. The calculated uranium exposures from 1949 through 1983 are discussed. 13 references, 1 table.

  17. Modeling Uranium-Proton Ion Exchange in Biosorption

    E-print Network

    Volesky, Bohumil

    Modeling Uranium-Proton Ion Exchange in Biosorption J I N B A I Y A N G A N D B O H U M I L V O L E, Quebec, Canada H3A 2B2 Biosorption of uranium metal ions by a nonliving protonated Sargassum fluitans seaweed biomass was used to remove the heavy metal uranium from the aqueous solution. Uranium biosorption

  18. Influence of uranium on bacterial communities: a comparison of natural uranium-rich soils with controls.

    PubMed

    Mondani, Laure; Benzerara, Karim; Carrière, Marie; Christen, Richard; Mamindy-Pajany, Yannick; Février, Laureline; Marmier, Nicolas; Achouak, Wafa; Nardoux, Pascal; Berthomieu, Catherine; Chapon, Virginie

    2011-01-01

    This study investigated the influence of uranium on the indigenous bacterial community structure in natural soils with high uranium content. Radioactive soil samples exhibiting 0.26% - 25.5% U in mass were analyzed and compared with nearby control soils containing trace uranium. EXAFS and XRD analyses of soils revealed the presence of U(VI) and uranium-phosphate mineral phases, identified as sabugalite and meta-autunite. A comparative analysis of bacterial community fingerprints using denaturing gradient gel electrophoresis (DGGE) revealed the presence of a complex population in both control and uranium-rich samples. However, bacterial communities inhabiting uraniferous soils exhibited specific fingerprints that were remarkably stable over time, in contrast to populations from nearby control samples. Representatives of Acidobacteria, Proteobacteria, and seven others phyla were detected in DGGE bands specific to uraniferous samples. In particular, sequences related to iron-reducing bacteria such as Geobacter and Geothrix were identified concomitantly with iron-oxidizing species such as Gallionella and Sideroxydans. All together, our results demonstrate that uranium exerts a permanent high pressure on soil bacterial communities and suggest the existence of a uranium redox cycle mediated by bacteria in the soil. PMID:21998695

  19. Influence of Uranium on Bacterial Communities: A Comparison of Natural Uranium-Rich Soils with Controls

    PubMed Central

    Mondani, Laure; Benzerara, Karim; Carrière, Marie; Christen, Richard; Mamindy-Pajany, Yannick; Février, Laureline; Marmier, Nicolas; Achouak, Wafa; Nardoux, Pascal; Berthomieu, Catherine; Chapon, Virginie

    2011-01-01

    This study investigated the influence of uranium on the indigenous bacterial community structure in natural soils with high uranium content. Radioactive soil samples exhibiting 0.26% - 25.5% U in mass were analyzed and compared with nearby control soils containing trace uranium. EXAFS and XRD analyses of soils revealed the presence of U(VI) and uranium-phosphate mineral phases, identified as sabugalite and meta-autunite. A comparative analysis of bacterial community fingerprints using denaturing gradient gel electrophoresis (DGGE) revealed the presence of a complex population in both control and uranium-rich samples. However, bacterial communities inhabiting uraniferous soils exhibited specific fingerprints that were remarkably stable over time, in contrast to populations from nearby control samples. Representatives of Acidobacteria, Proteobacteria, and seven others phyla were detected in DGGE bands specific to uraniferous samples. In particular, sequences related to iron-reducing bacteria such as Geobacter and Geothrix were identified concomitantly with iron-oxidizing species such as Gallionella and Sideroxydans. All together, our results demonstrate that uranium exerts a permanent high pressure on soil bacterial communities and suggest the existence of a uranium redox cycle mediated by bacteria in the soil. PMID:21998695

  20. Decontamination of uranium-contaminated steel surfaces by hydroxycarboxylic acid with uranium recovery.

    PubMed

    Francis, A J; Dodge, C J; McDonald, J A; Halada, G P

    2005-07-01

    We developed a simple, safe method to remove uranium from contaminated metallic surfaces so that the materials can be recycled or disposed of as low-level radioactive or nonradioactive waste. Surface analysis of rusted uranium-contaminated plain carbon-steel coupons by X-ray photoelectron spectroscopy and Rutherford backscattering spectroscopy showed that uranium was predominantly associated with ferrihydrite, lepidocrocite, and magnetite, or occluded in the matrix of the corrosion product as uranyl hydroxide and schoepite (UO3 x 2H2O). Citric acid formulations, consisting of oxalic acid-hydrogen peroxidecitric acid (OPC) or citric acid-hydrogen peroxidecitric acid (CPC), were used to remove uranium from the coupons. The efficiency of uranium removal varied from 68% to 94% depending on the extent of corrosion, the association of uranium with the iron oxide matrix, and the accessibility of the occluded contaminant. Decontaminated coupons clearly showed evidence of the extensive removal of rust and uranium. The waste solutions containing uranium and iron from decontamination by OPC and CPC were treated first by subjecting them to biodegradation followed by photodegradation. Biodegradation of a CPC solution by Pseudomonas fluorescens resulted in the degradation of the citric acid with concomitant precipitation of Fe (>96%), whereas U that remained in solution was recovered (>99%) by photodegradation as schoepite. In contrast, in an OPC solution citric acid was biodegraded but not oxalic acid, and both Fe and U remained in solution. Photodegradation of this OPC solution resulted in the precipitation of iron as ferrihydrite and uranium as uranyl hydroxide. PMID:16053105

  1. Environmental impact of uranium mining and milling: the Canadian experience

    Microsoft Academic Search

    Dory

    1982-01-01

    An outline of the basic regulatory approaches for minimization of environmental impacts from uranium mining and milling in Canada is presented. Requirements of the Atomic Energy Control Board (AECB) currently being enforced are much more rigorous for uranium mill tailings than for other tailings, even though the environmentl hazards of uranium mill tailings are generally the same order of magnitude

  2. Uranium mining in Australia: Environmental impact, radiation releases and rehabilitation

    Microsoft Academic Search

    G. M. Mudd

    The mining and export of uranium and the impacts (and risks) of the nuclear industry have long been a contentious issue in Australia. The ongoing debate primarily relates to the established and potential dangers of ionizing radiation released to the environment from nuclear facilities, such as uranium mines or research reactors. By 2002, three uranium milling projects are operating with

  3. Estimating terrestrial uranium and thorium by antineutrino flux measurements

    E-print Network

    Mcdonough, William F.

    Estimating terrestrial uranium and thorium by antineutrino flux measurements Stephen T. Dye, and approved November 16, 2007 (received for review July 11, 2007) Uranium and thorium within the Earth produce of uranium and thorium concentrations in geological reservoirs relies largely on geochemi- cal model

  4. Observation of the uranium 235 nuclear magnetic resonance signal (*)

    E-print Network

    Paris-Sud XI, Université de

    L-1017 Observation of the uranium 235 nuclear magnetic resonance signal (*) H. Le Bail, C. Chachaty signal de résonance magnétique nucléaire de l'isotope 235 de l'uranium est présentée. Elle a été effectuée sur l'hexafluorure d'uranium pur, à l'état liquide à 380 K. Le rapport gyromagnétique mesuré est

  5. Dossier Miss Terre Uranium. Un mot qui ne laisse pas

    E-print Network

    van Tiggelen, Bart

    Dossier Miss Terre Uranium. Un mot qui ne laisse pas indifférent. On pense centrale nucléaire, bombe atomique, radioactivité... Mais l'uranium, c'est aussi une substance précieuse qui permet de son message. En se désintégrant, l'uranium présent naturellement dans l'eau de mer produit d

  6. Tables des principaux minerais d'uranium et de thorium

    E-print Network

    Paris-Sud XI, Université de

    233 Tables des principaux minerais d'uranium et de thorium Par B. SZILARD [Faculté des Sciences de minerais d'uranium et de thorium avec leurs données les plus importantes, telles que la com- position, la teneur en uranium et en thorium, la provenance et quelques indications générales. La liste ne prétend pas

  7. Plutonium recovery from spent reactor fuel by uranium displacement

    DOEpatents

    Ackerman, J.P.

    1992-03-17

    A process is described for separating uranium values and transuranic values from fission products containing rare earth values when the values are contained together in a molten chloride salt electrolyte. A molten chloride salt electrolyte with a first ratio of plutonium chloride to uranium chloride is contacted with both a solid cathode and an anode having values of uranium and fission products including plutonium. A voltage is applied across the anode and cathode electrolytically to transfer uranium and plutonium from the anode to the electrolyte while uranium values in the electrolyte electrolytically deposit as uranium metal on the solid cathode in an amount equal to the uranium and plutonium transferred from the anode causing the electrolyte to have a second ratio of plutonium chloride to uranium chloride. Then the solid cathode with the uranium metal deposited thereon is removed and molten cadmium having uranium dissolved therein is brought into contact with the electrolyte resulting in chemical transfer of plutonium values from the electrolyte to the molten cadmium and transfer of uranium values from the molten cadmium to the electrolyte until the first ratio of plutonium chloride to uranium chloride is reestablished.

  8. Occurrence of Metastudtite (Uranium Peroxide Dihydrate) at a FUSRAP Site

    Microsoft Academic Search

    C. M. Young; K. A. Nelson; G. T. Stevens; V. J. Grassi

    2006-01-01

    Uranium concentrations in groundwater in a localized area of a site exceed the USEPA Maximum Contaminant Level (MCL) by a factor of one thousand. Although the groundwater seepage velocity ranges up to 0.7 meters per day (m\\/day), data indicate that the uranium is not migrating in groundwater. We believe that the uranium is not mobile because of local geochemical conditions

  9. Uranium Sequestration by Aluminum Phosphate Minerals in Unsaturated Soils

    Microsoft Academic Search

    Jerden; James L. Jr

    2007-01-01

    A mineralogical and geochemical study of soils developed from the unmined Coles Hill uranium deposit (Virginia) was undertaken to determine how phosphorous influences the speciation of uranium in an oxidizing soil\\/saprolite system typical of the eastern United States. This paper presents mineralogical and geochemical results that identify and quantify the processes by which uranium has been sequestered in these soils.

  10. Plutonium recovery from spent reactor fuel by uranium displacement

    DOEpatents

    Ackerman, John P. (Downers Grove, IL)

    1992-01-01

    A process for separating uranium values and transuranic values from fission products containing rare earth values when the values are contained together in a molten chloride salt electrolyte. A molten chloride salt electrolyte with a first ratio of plutonium chloride to uranium chloride is contacted with both a solid cathode and an anode having values of uranium and fission products including plutonium. A voltage is applied across the anode and cathode electrolytically to transfer uranium and plutonium from the anode to the electrolyte while uranium values in the electrolyte electrolytically deposit as uranium metal on the solid cathode in an amount equal to the uranium and plutonium transferred from the anode causing the electrolyte to have a second ratio of plutonium chloride to uranium chloride. Then the solid cathode with the uranium metal deposited thereon is removed and molten cadmium having uranium dissolved therein is brought into contact with the electrolyte resulting in chemical transfer of plutonium values from the electrolyte to the molten cadmium and transfer of uranium values from the molten cadmium to the electrolyte until the first ratio of plutonium chloride to uranium chloride is reestablished.

  11. National Uranium Resource Evaluation, Klamath Falls Quadrangle, Oregon and California

    SciTech Connect

    Castor, S.B.; Berry, M.R.; Robins, J.W.

    1982-07-01

    The Klamath Falls Quadrangle, Oregon, was evaluated to identify and delineate areas favorable for uranium deposits according to criteria developed for the National Uranium Resource Evaluation. Surface radiometric reconnaissance and geochemical sampling were used for overall evaluation of the quadrangle. Detailed rock sampling, geologic mapping, and examinations of uranium mines and occurrences were performed in suspected favorable areas. Results of the work indicate good potential for shallow hydrothermal volcanogenic uranium deposits in the Lakeview favorable area, which comprises a northwest-trending belt of rhyolite intrusions in the eastern half of the quadrangle. The young age, peraluminous chemistry, and low thorium-to-uranium ratios of the rhyolite intrusions, as well as low uranium content of groundwater samples, indicate that uranium has not been leached from the intrusions by ground water. Therefore, supergene uranium deposits are not likely in the area. Scattered occurrences of ash-flow tuff in the east half of the quadrangle that contain high uranium and (or) thorium contents, and four occurrences of secondary uranium minerals in ash-flow tuff, indicate possible uranium deposits in ash flows in a poorly defined area that is partially coextensive with the Lakeview favorable area. Small granitic plutons with associated quartz-tourmaline breccia veins and base-metal occurrences may also be favorable for uranium deposits but were not examined during this study.

  12. Calculating Capstone Depleted Uranium Aerosol Concentrations from Beta Activity Measurements

    Microsoft Academic Search

    Frances Szrom; Gerald A. Falo; MaryAnn Parkhurst; Jeffrey J. Whicker; David P. Alberth

    2009-01-01

    Beta activity measurements were used as surrogate measurements of uranium mass in aerosol samples collected during the field testing phase of the Capstone Depleted Uranium (DU) Aerosol Study. These aerosol samples generated by the perforation of armored combat vehicles were used to characterize the depleted uranium (DU) source term for the subsequent human health risk assessment (HHRA) of Capstone aerosols.

  13. Appendix IV. Risks Associated with Conventional Uranium Milling Introduction

    E-print Network

    ), "Final Generic Environmental Impact Statement on Uranium Milling Volume 1 and 2" by U.S. NRC (1980), "Final Environmental Impact Statement for Standards for the Control of Byproduct Materials from Uranium Impact Statement (GEIS) on uranium milling which would provide more detailed information and may include

  14. DETERMINATION OF MICROGRAM QUANTITIES OF URANIUM IN THORIUM

    Microsoft Academic Search

    V. T. Athavale; L. M. Mahajan; N. R. Thakoor; M. S. Varde

    1959-01-01

    Uranium present in ricro amounts in thorium is extracted with 5% ; tributyl phosphate in presence of EDTA at ph 2.5. balcium nitrate is used as ; salting agent. Uranium is back-extracted with ammonium carbonate and determined ; fluorimetrically. Thoria samples containing as little as 0.4 ppm of uranium were ; analyzed. (auth);

  15. Case Study/ Effects of Groundwater Development on Uranium

    E-print Network

    Case Study/ Effects of Groundwater Development on Uranium: Central Valley, California, USA Abstract Uranium (U) concentrations in groundwater in several parts of the eastern San Joaquin Valley. Uranium (U) concentrations above the California Maximum Contaminant Level (CA-MCL) of 20 pic- ocuries per

  16. Uranium Reduction in Sediments under Diffusion-Limited Transport of

    E-print Network

    Hazen, Terry

    Uranium Reduction in Sediments under Diffusion-Limited Transport of Organic Carbon T E T S U K, Chicago, Illinois 60637 Costly disposal of uranium (U) contaminated sediments is motivating research. Introduction Uranium (U) is an important subsurface contaminant at sites associated with its mining

  17. Effects of uranium on the metabolism of zebrafish, Danio rerio

    E-print Network

    Paris-Sud XI, Université de

    Effects of uranium on the metabolism of zebrafish, Danio rerio Starrlight Augustine1 , B for nuclear energy results in heightened levels of uranium (U) in aquatic systems which present a potential, growth, metabolism, reproduction, uranium, zebrafish 2 hal-00760075,version1-3Dec2012 #12;1 Introduction

  18. Standard Review Plan for In Situ Leach Uranium

    E-print Network

    NUREG-1569 Standard Review Plan for In Situ Leach Uranium Extraction License Applications Final Washington, DC 20555-0001 #12;NUREG-1569 Standard Review Plan for In Situ Leach Uranium Extraction License OF A STANDARD REVIEW PLAN (NUREG­1569) FOR STAFF REVIEWS FOR IN SITU LEACH URANIUM EXTRACTION LICENSE

  19. Soil to plant transfer of 238 Th on a uranium

    E-print Network

    Hu, Qinhong "Max"

    Soil to plant transfer of 238 U, 226 Ra and 232 Th on a uranium mining-impacted soil from species grown in soils from southeastern China contaminated with uranium mine tailings were analyzed. Keywords: Uranium; Thorium; Radium; Tailings-contaminated soil; Soileplant transfer 1. Introduction

  20. Recovery of uranium from biological adsorbents?desorption equilibrium

    Microsoft Academic Search

    M. Tsezos

    1984-01-01

    tively low cost. Furthermore, the available uranium up- take equilibrium data have suggested that hydrogen ions can compete very effectively with uranium for the active sites on the microbial biomass and result in reduced over- all uranium uptake by R. arrhi~us.~ A relatively concen- trated acid solution could, therefore, act as an elution agent. Experimental data that have been reported

  1. Interaction of uranium oxides with dinitrogen tetroxide

    NASA Astrophysics Data System (ADS)

    Kobets, L. V.; Klavsut', G. N.

    1990-08-01

    Data on the interaction of nitrogen oxides in different oxidation states with dinitrogen tetroxide in the temperature range 273-1073 K and in the pressure range 0.1-10 MPa are surveyed. The mechanisms of the interaction of the dissociating N2O4rightleftarrows2NO2rightleftarrows2NO + O2 system, liquid N2O4, and N2O4 -organic solvent mixtures with uranium oxides are discussed as a function of the oxidation state of uranium, the specific surface and structure of the oxides, the state of aggregation of N2O4, the presence of impurities in the latter, and the presence of organic solvents. The behaviour of uranium oxides in relation to that of the other metal oxides is subjected to a comparative analysis. The bibliography includes 91 references.

  2. TRACE ELEMENT ANALYSES OF URANIUM MATERIALS

    SciTech Connect

    Beals, D; Charles Shick, C

    2008-06-09

    The Savannah River National Laboratory (SRNL) has developed an analytical method to measure many trace elements in a variety of uranium materials at the high part-per-billion (ppb) to low part-per-million (ppm) levels using matrix removal and analysis by quadrapole ICP-MS. Over 35 elements were measured in uranium oxides, acetate, ore and metal. Replicate analyses of samples did provide precise results however none of the materials was certified for trace element content thus no measure of the accuracy could be made. The DOE New Brunswick Laboratory (NBL) does provide a Certified Reference Material (CRM) that has provisional values for a series of trace elements. The NBL CRM were purchased and analyzed to determine the accuracy of the method for the analysis of trace elements in uranium oxide. These results are presented and discussed in the following paper.

  3. Bone growth is impaired by uranium intoxication.

    PubMed

    Ubios, A M; Piloni, M J; Marzorati, M; Cabrini, R L

    Acute and chronic uranium intoxication leads to the inhibition of bone formation and impaired bone modeling and remodeling. As these are processes directly involved in bone growth the aim of this paper is to present a biometric study of bone growth--tibiae and mandibles of rats intoxicated with uranium. Wistar ratios weighing 60-80 g were used as follows, a) one intraperitoneal injection (IPI, 2 mg/Kg of body weight)) of uranyl nitrate; b) 30 daily applications on the dorsal skin of aliquots of a mixture of U308, concentrated at 2% and at 4%--percutaneous absorption(PA)-. Tibia and mandible length were smaller in both experimental groups than in their respective controls. Some of the mandibular parameters were lower in intoxicated animals than their controls which in turn results in the alteration of the mandibular shape. We conclude that impairment in bone growth can be achieved by uranium intoxication. PMID:11885227

  4. Health concerns in uranium mining and milling

    SciTech Connect

    Archer, V.E.

    1981-07-01

    Mortality of uranium miners from both lung cancer and other respiratory diseases is strongly dependent on exposure to radon daughters, cigarette smoking and height. Lung cancer among 15 different mining groups (uranium, iron, lead, zinc) was analyzed to determine what factors influence incidence and the induction-latent period. At low exposure or exposure rates, alpha radiation is more efficient in inducing lung cancer, producing an upward convex exposure-response curve. The induction-latent period is shortened by increased age at start of mining, by cigarette smoking and by high exposure rates. Instead of extrapolating downward from high exposures to estimate risk at low levels, it is suggested that it might be more appropriate to use cancer rates associated with background radiation as the lowest point on the exposure-response curve. Although health risks are much greater in uranium mines than mills, there is some health risk in the mills from long-lived radioactive materials.

  5. Cleaning of uranium vs machine coolant formulations

    SciTech Connect

    Cristy, S.S.; Byrd, V.R.; Simandl, R.F.

    1984-10-01

    This study compares methods for cleaning uranium chips and the residues left on chips from alternate machine coolants based on propylene glycol-water mixtures with either borax, ammonium tetraborate, or triethanolamine tetraborate added as a nuclear poison. Residues left on uranium surfaces machined with perchloroethylene-mineral oil coolant and on surfaces machined with the borax-containing alternate coolant were also compared. In comparing machined surfaces, greater chlorine contamination was found on the surface of the perchloroethylene-mineral oil machined surfaces, but slightly greater oxidation was found on the surfaces machined with the alternate borax-containing coolant. Overall, the differences were small and a change to the alternate coolant does not appear to constitute a significant threat to the integrity of machined uranium parts.

  6. Monitoring genotoxic exposure in uranium mines

    SciTech Connect

    Sram, R.J.; Vesela, D.; Vesely, D. [Institute of Experimental Medicine, Prague (Czech Republic)] [and others

    1993-10-01

    Recent data from deep uranium mines in Czechoslovakia indicated that miners are exposed to other mutagenic factors in addition to radon daughter products. Mycotoxins were identified as a possible source of mutagens in these mines. Mycotoxins were examined in 38 samples from mines and in throat swabs taken from 116 miners and 78 controls. The following mycotoxins were identified from mines samples: aflatoxins B{sub 1} and G1, citrinin, citreoviridin, mycophenolic acid, and sterigmatocystin. Some mold strains isolated from mines and throat swabs were investigated for mutagenic activity by the SOS chromotest and Salmonella assay with strains TA100 and TA98. Mutagenicity was observed, especially with metabolic activation in citro. These data suggest that mycotoxins produced by molds in uranium mines are a new genotoxic factor im uranium miners. 17 refs., 4 tabs.

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

    E-print Network

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

    2014-09-29

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

  8. The Characterisation of Uranium-Oxide Surfaces.

    NASA Astrophysics Data System (ADS)

    Holmes, Nigel Richard

    Available from UMI in association with The British Library. These studies show that x-ray photoelectron spectroscopy (X.p.s.) can be used to determine the overall oxidation state and the uranium valences present at the surface of a uranium oxide. By comparing the spectra recorded from an unknown oxide with those obtained from reference compounds it should be possible to predict the adopted structure type. X.p.s. cannot however distinguish between uranium oxides containing identical uranium oxidation states but different structures, such as the four UO_3 phases studied in this work. In the infra-red studies it was found that all of the uranium oxides studies had characteristic absorption spectra, and this can distinguish between samples with the same composition but different structures. In addition the layered structure oxides such as alpha-U_3O _6 and most of the UO_3 phases have strong vibrational absorptions which are absent in the spectra of the fluorite-type uranium oxides. This makes infra-red spectroscopy a useful technique for determining the types of oxides present in a partially oxidised sample. The X-ray diffraction (X.r.d.) studies in this work found that the initial oxidation product of UO_2 at temperatures between 125 ^circC and 135^ circC could be indexed on a cubic unit cell smaller than that of U_4O _9. From a comparison with previously reported data it was concluded that this oxide could be a low temperature alpha-U_3O _7 phase. By considering previously reported X.r.d. data for the uranium oxides it was also found that the structures could be divided into two general types, the fluorite structure typified by UO_2 and the layered structure typified by alpha-U_3O _6. From the close similarity of the hexagonally packed uranium planes present in both structure types a mechanism for the UO_2 to alpha-U_3O _6 phase transformation is proposed.

  9. Uranium in NIMROC standard igneous rock samples

    NASA Technical Reports Server (NTRS)

    Rowe, M. W.; Herndon, J. M.

    1976-01-01

    Results are reported for analysis of the uranium in multiple samples of each of six igneous-rock standards (dunite, granite, lujavrite, norite, pyroxenite, and syenite) prepared as geochemical reference standards for elemental and isotopic compositions. Powdered rock samples were examined by measuring delayed neutron emission after irradiation with a flux of the order of 10 to the 13th power neutrons/sq cm per sec in a nuclear reactor. The measurements are shown to compare quite favorably with previous uranium determinations for other standard rock samples.

  10. Evaporation of Enriched Uranium Solutions Containing Organophosphates

    SciTech Connect

    Pierce, R.A.

    1999-03-18

    The Savannah River Site has enriched uranium (EU) solution which has been stored for almost 10 years since being purified in the second uranium cycle of the H area solvent extraction process. The preliminary SRTC data, in conjunction with information in the literature, is promising. However, very few experiments have been run, and none of the results have been confirmed with repeat tests. As a result, it is believed that insufficient data exists at this time to warrant Separations making any process or program changes based on the information contained in this report. When this data is confirmed in future testing, recommendations will be presented.

  11. 10 CFR 760.1 - Uranium leases on lands controlled by DOE. (Domestic Uranium Program Circular No. 760.1, formerly...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...controlled by DOE. (Domestic Uranium Program Circular No. 760.1, formerly (AEC) Domestic Uranium Program Circular 8, 10 CFR 60.8). 760.1 Section 760.1 Energy DEPARTMENT OF ENERGY DOMESTIC URANIUM...

  12. Steady State Sputtering Yields and Surface Compositions of Depleted Uranium and Uranium Carbide bombarded by 30 keV Gallium or 16 keV Cesium Ions.

    SciTech Connect

    Siekhaus, W. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Teslich, N. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Weber, P. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-10-23

    Depleted uranium that included carbide inclusions was sputtered with 30keV gallium ions or 16kev cesium ions to depths much greater than the ions’ range, i.e. using steady state sputtering. The recession of both the uranium’s and uranium carbide’s surfaces and the ion corresponding fluences were used to determine the steady state target sputtering yields of both uranium and uranium carbide, i.e. 6.3 atoms of uranium and 2.4 units of uranium carbide eroded per gallium ion, and 9.9 uranium atoms and 3.65 units of uranium carbide eroded by cesium ions. The steady state surface composition resulting from the simultaneous gallium or cesium implantation and sputter-erosion of uranium and uranium carbide were calculated to be U??Ga??, (UC)??Ga?? and U??Cs?, (UC)??Cs??, respectively.

  13. Conversion and Blending Facility highly enriched uranium to low enriched uranium as metal. Revision 1

    SciTech Connect

    NONE

    1995-07-05

    The mission of this Conversion and Blending Facility (CBF) will be to blend surplus HEU metal and alloy with depleted uranium metal to produce an LEU product. The primary emphasis of this blending operation will be to destroy the weapons capability of large, surplus stockpiles of HEU. The blended LEU product can only be made weapons capable again by the uranium enrichment process. The blended LEU will be produced as a waste suitable for storage or disposal.

  14. Enhanced Uranium Immobilization and Reduction by Geobacter sulfurreducens Biofilms

    PubMed Central

    Cologgi, Dena L.; Speers, Allison M.; Bullard, Blair A.; Kelly, Shelly D.

    2014-01-01

    Biofilms formed by dissimilatory metal reducers are of interest to develop permeable biobarriers for the immobilization of soluble contaminants such as uranium. Here we show that biofilms of the model uranium-reducing bacterium Geobacter sulfurreducens immobilized substantially more U(VI) than planktonic cells and did so for longer periods of time, reductively precipitating it to a mononuclear U(IV) phase involving carbon ligands. The biofilms also tolerated high and otherwise toxic concentrations (up to 5 mM) of uranium, consistent with a respiratory strategy that also protected the cells from uranium toxicity. The enhanced ability of the biofilms to immobilize uranium correlated only partially with the biofilm biomass and thickness and depended greatly on the area of the biofilm exposed to the soluble contaminant. In contrast, uranium reduction depended on the expression of Geobacter conductive pili and, to a lesser extent, on the presence of the c cytochrome OmcZ in the biofilm matrix. The results support a model in which the electroactive biofilm matrix immobilizes and reduces the uranium in the top stratum. This mechanism prevents the permeation and mineralization of uranium in the cell envelope, thereby preserving essential cellular functions and enhancing the catalytic capacity of Geobacter cells to reduce uranium. Hence, the biofilms provide cells with a physically and chemically protected environment for the sustained immobilization and reduction of uranium that is of interest for the development of improved strategies for the in situ bioremediation of environments impacted by uranium contamination. PMID:25128347

  15. Extractive Electrospray Ionization Mass Spectrometry for Uranium Chemistry Studies

    PubMed Central

    Chen, Huanwen; Luo, Mingbiao; Xiao, Saijin; Ouyang, Yongzhong; Zhou, Yafei; Zhang, Xinglei

    2013-01-01

    Uranium chemistry is of sustainable interest. Breakthroughs in uranium studies make serious impacts in many fields including chemistry, physics, energy and biology, because uranium plays fundamentally important roles in these fields. Substantial progress in uranium studies normally requires development of novel analytical tools. Extractive electrospray ionization mass spectrometry (EESI-MS) is a sensitive technique for trace detection of various analytes in complex matrices without sample pretreatment. EESI-MS shows excellent performance for monitoring uranium species in various samples at trace levels since it tolerates extremely complex matrices. Therefore, EESI-MS is an alternative choice for studying uranium chemistry, especially when it combines ion trap mass spectrometry. In this presentation, three examples of EESI-MS for uranium chemistry studies will be given, illustrating the potential applications of EESI-MS in synthesis chemistry, physical chemistry, and analytical chemistry of uranium. More specifically, case studies on EESI-MS for synthesis and characterization of novel uranium species, and for rapid detection of uranium and its isotope ratios in various samples will be presented. Novel methods based on EESI-MS for screening uranium ores and radioactive iodine-129 will be presented. PMID:24349940

  16. Repository criticality control for {sup 233}U using depleted uranium

    SciTech Connect

    Forsberg, C.W.; Elam, K.R.; Hopper, C.M.

    1999-07-01

    The US is evaluating methods for the disposition of excess weapons-usable {sup 233}U, including disposal in a repository. Isotopic dilution studies were undertaken to determine how much depleted uranium (DU) would need to be added to the {sup 233}U to minimize the potential for nuclear criticality in a repository. Numerical evaluations were conducted to determine the nuclear equivalence of different {sup 235}U enrichments to {sup 233}U isotopically diluted with DU containing 0.2 wt% {sup 235}U. A homogeneous system of silicon dioxide, water, {sup 233}U, and DU, in which the ratio of each component was varied, was used to determine the conditions of maximum nuclear reactivity. In terms of preventing nuclear criticality in a repository, there are three important limits from these calculations. 1. Criticality safe in any nonnuclear system: The required isotopic dilution to ensure criticality under all conditions, except in the presence of man-made nuclear materials (beryllium, etc.), is {approximately}1.0% {sup 235}U in {sup 238}U. The equivalent {sup 233}U enrichment level is 0.53 wt% {sup 233}U in DU. 2. Critically safe in natural systems: The lowest {sup 235}U enrichment found in a natural reactor at shutdown was {approximately}1.3%. French studies, based on the characteristics of natural uranium ore bodies, indicate that a minimum enrichment of {approximately}1.28% {sup 235}U is required for criticality. These data suggest that nuclear criticality from migrating uranium is not realistic unless the {sup 235}U enrichments exceed {approximately}1.3%, which is a result that is equivalent to 0.72% {sup 233}U in DU. 3. Criticality safety equivalent to light water reactor (LWR) spent nuclear fuel (SNF): The {sup 233}U can be diluted with DU so that the uranium criticality characteristics match SNF uranium. Whatever repository criticality controls are used for SNF can then be used for {sup 233}U. The average LWR SNF assay (after decay of plutonium isotopes to uranium isotopes) is 1.5% {sup 235}U equivalent in {sup 238}U. This is equivalent to diluting {sup 233}U to 0.81% in DU.

  17. Pyrophoricity of uranium in long-term storage environments

    SciTech Connect

    Solbrig, C W; Krsul, J R; Olsen, D N

    1994-01-01

    A corrosion cycle for uranium is postulated which can be used to assess whether a given storage situation might produce fire hazards and/or continual uranium corrosion. A significant reaction rate of uranium and moisture occurs at room temperature which produces uranium oxide and hydrogen. If the hydrogen cannot escape, it will react slowly with uranium to form uranium hydride. The hydride is pyrophoric at room temperature when exposed to air. Either the hydrogen or the hydride can produce a dangerous situation as demonstrated by two different incidents described here. Long-term corrosion will occur even if the normal precautions are taken as is demonstrated by the long-term storage of stainless steel clad uranium fuel plates. The major initiator of these problems is attributed to any moisture condensed on the metal or any brought in by the cover gas. The postulated corrosion cycle is used to suggest ways to circumvent these problems.

  18. Battlefield use of depleted uranium and the health of veterans.

    PubMed

    Bolton, J P G; Foster, C R M

    2002-09-01

    Depleted uranium munitions have been used in recent military operations in both the Gulf and the Balkans and there have been concerns that exposure to depleted uranium may be a cause of 'Gulf War Syndrome' and cancer clusters. We recount the properties of depleted uranium, its military uses and the situations in which personnel may be exposed. Following a review of scientific literature, the health effects of depleted and natural uranium exposure are described and the major outcomes of research into Gulf Veterans' Illnesses are summarised. We conclude that, although there is the potential for uranium exposures to cause renal damage or lung cancer, the risk of harm following depleted uranium exposure in military settings seems to be low. We advise on the management of casualties exposed to depleted uranium and suggest control measures that may be appropriate to protect personnel who provide casualty care. PMID:12469421

  19. MEETING REPORTS: SRP Scientific Meeting: Depleted Uranium

    Microsoft Academic Search

    David Kestell

    2002-01-01

    London, January 2002 The meeting was organised by the SRP to review current research and discuss the use, dispersion into the environment and radiological impact of depleted uranium (DU) by the UK and US in recent military conflicts. Brian Spratt chaired the morning session of the meeting and stressed the need to gauge the actual risks involved in using DU

  20. URANIUM TRIOXIDE IN A FLUIDIZED BED REACTOR

    Microsoft Academic Search

    W. C. Philoon; E. F. Sanders; W. T. Trask

    1960-01-01

    A continuous method for the production of uranium trioxide from uranyl ; nitrate solution was developed, and its advantages over the batch process pointed ; out. Uranyl nitrate and fluidizing air are sprayed into the reactor, heat being ; supplied by molten heat transfer salt. The UOâ product overflows from the ; reactor into a packaging station. The best range

  1. THE CORROSION BEHAVIORS OF PLUTONIUM AND URANIUM

    Microsoft Academic Search

    Waber

    1958-01-01

    The many similarities in the chemical reactivity of plutonium and ; uranium were used to gain a deeper understanding of the mechanisms involved in ; the corrosion behavior of these metals and their alloys. It may be concluded ; that the reaction in aqueous environment is controlled by the rate of one or more ; reactions occurring at local anodes.

  2. Measurements of radon around closed uranium mines

    Microsoft Academic Search

    Sadaaki Furuta; Kimio Ito; Yuu Ishimori

    2002-01-01

    There are several waste rock yards at closed uranium mines around Ningyo-toge, in the Western Honshu Island of Japan, and measurements of radon were carried out by both the passive method and the sampling method around these yards. As comparatively high radon concentrations were observed in two districts through routine measurements, more detailed measurements were made by the passive method

  3. Semiconductor neutron detectors using depleted uranium oxide

    NASA Astrophysics Data System (ADS)

    Kruschwitz, Craig A.; Mukhopadhyay, Sanjoy; Schwellenbach, David; Meek, Thomas; Shaver, Brandon; Cunningham, Taylor; Auxier, Jerrad Philip

    2014-09-01

    This paper reports on recent attempts to develop and test a new type of solid-state neutron detector fabricated from uranium compounds. It has been known for many years that uranium oxide (UO2), triuranium octoxide (U3O8) and other uranium compounds exhibit semiconducting characteristics with a broad range of electrical properties. We seek to exploit these characteristics to make a direct-conversion semiconductor neutron detector. In such a device a neutron interacts with a uranium nucleus, inducing fission. The fission products deposit energy-producing, detectable electron-hole pairs. The high energy released in the fission reaction indicates that noise discrimination in such a device has the potential to be excellent. Schottky devices were fabricated using a chemical deposition coating technique to deposit UO2 layers a few microns thick on a sapphire substrate. Schottky devices have also been made using a single crystal from UO2 samples approximately 500 microns thick. Neutron sensitivity simulations have been performed using GEANT4. Neutron sensitivity for the Schottky devices was tested experimentally using a 252Cf source.

  4. Neutron Resonance Parameters for U-233 (Uranium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Volume 24 `Neutron Resonance Parameters' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms'. It provides the neutron resonance parameters for the isotope U-233 (Uranium). Also included are parameters of p-resonances from asymmetry in fission.

  5. The hazard posed by depleted uranium munitions

    Microsoft Academic Search

    Steve Fetter; Frank N. von Hippel

    2000-01-01

    This paper assesses the radiological and chemical hazards resulting from the use of depleted uranium (DU) munitions. Due to the low radioactivity of DU, radiological hazards to individuals would become significant in comparison to natural background radiation doses only in cases of prolonged contact—for example, when shards of a DU penetrator remain embedded in a soldier's body. Although the radiation

  6. Characterisation of projectiles composed of depleted uranium

    Microsoft Academic Search

    R. Pollanen; T. K. Ikaheimonen; S. Klemola; V.-P. Vartti; K. Vesterbacka; S. Ristonmaa; T. Honkamaa; P. Sipilaa; I. Jokelainen; A. Kosunen; R. Zilliacus; M. Kettunen; M. Hokkanen

    2003-01-01

    Projectiles suspected to be composed of depleted uranium (DU) were found in Kosovo. Their properties were analysed using alpha and gamma ray spectrometry, mass spectrometry and electron microscopy. They were found to be composed of DU with small amounts of other elements such as Ti. 236U was detected in the penetrators, reflecting the use of reprocessed fuel. No transuranium elements

  7. EVALUATION OF URANIUM-SILICON ALLOY

    Microsoft Academic Search

    Ryan

    1954-01-01

    A fuel element resistant to core failure at high HAPO irradiation ; exposure levels was desired and an alloy fuel element which might meet this ; requirement was studied. The uranium -1.5 at% silicon alloy was selected as it ; does not quench crack during heat treatment, can be fabricated under production ; conditions, and has a low reactivity loss.

  8. Uranium miner lung cancer study. Final report

    SciTech Connect

    Saccomanno, G.

    1986-06-01

    This study on uranium miners was started in 1957 and extended through June 30, 1986. It consisted of the routine screening of sputum from uranium miners of the Colorado Plateau, and collection of surgical and autopsy material from uranium miners who developed lung cancer. The projects resulted in: (1) Proof, for the first time, that cancer takes from 10 to 15 years to develop from the maximum accumulated carcinogenic insult and can be demonstrated through progressive cellular changes of the bronchial tree; (2) Development of a method for preserving, concentrating, and processing sputum samples. This is known as the Saccomanno Technique, and is used worldwide in diagnosing lung cancer; (3) Publication of the 1st and 2nd editions of a full-color textbook entitled ''Diagnostic Pulmonary Cytology;'' (4) Presentation of conclusive data on the effects of cigarette smoking and alpha progeny radiation on uranium miners, and information on safe radiation exposure levels; (5) Development of a brush-wash tube for collecting, concentrating, and preparing bronchial brushings and washings; (6) Development of cytological criteria which has improved sensitivity from 30% to about 60%; (7) Development of criteria for cytologic identification of carcinoma in situ, making it possible to diagnose lung cancer before it can be detected on chest x-ray.

  9. Statistical design of a uranium corrosion experiment

    SciTech Connect

    Wendelberger, Joanne R [Los Alamos National Laboratory; Moore, Leslie M [Los Alamos National Laboratory

    2009-01-01

    This work supports an experiment being conducted by Roland Schulze and Mary Ann Hill to study hydride formation, one of the most important forms of corrosion observed in uranium and uranium alloys. The study goals and objectives are described in Schulze and Hill (2008), and the work described here focuses on development of a statistical experiment plan being used for the study. The results of this study will contribute to the development of a uranium hydriding model for use in lifetime prediction models. A parametric study of the effect of hydrogen pressure, gap size and abrasion on hydride initiation and growth is being planned where results can be analyzed statistically to determine individual effects as well as multi-variable interactions. Input to ESC from this experiment will include expected hydride nucleation, size, distribution, and volume on various uranium surface situations (geometry) as a function of age. This study will also address the effect of hydrogen threshold pressure on corrosion nucleation and the effect of oxide abrasion/breach on hydriding processes. Statistical experiment plans provide for efficient collection of data that aids in understanding the impact of specific experiment factors on initiation and growth of corrosion. The experiment planning methods used here also allow for robust data collection accommodating other sources of variation such as the density of inclusions, assumed to vary linearly along the cast rods from which samples are obtained.

  10. DIFFUSION OF FISSION GAS IN URANIUM

    Microsoft Academic Search

    1963-01-01

    The diffusion coefficient and activation energy for diffusion of xenon-; 133 in uranium metal have been determined for a number of varying sample ; conditions, with metal of hlgh purity and commercial purity. Thin foil samples ; were neutron irradiated, in groups, under conditions such as to produce optimum ; uniformity of fission product concentration throughout the samples. The samples

  11. Chapter 2: uranium mines and mills

    Microsoft Academic Search

    OConnell

    1983-01-01

    This chapter will be included in a larger ASCE Committee Report. Uranium mining production is split between underground and open pit mines. Mills are sized to produce yellowcake concentrate from hundreds to thousands of tons of ore per day. Miner's health and safety, and environmental protection are key concerns in design. Standards are set by the US Mine Safety and

  12. Production of uranium ore in capitalist countries

    Microsoft Academic Search

    N. I. Chesnokov; V. G. Ivanov

    1973-01-01

    The uranium deposits of the USA are concentrated in the sedimentary rocks of the Colorado plateau [2, 12]. The ore bodies are adapted to arkosic sandstones, conglomerates, limestones, and argillites. The reserves are distributed into a rather small number of large deposits and a large number of small deposits. Large deposits, each with reserves of from 50 to 100 thousand

  13. Geodatabase of the South Texas Uranium District

    Microsoft Academic Search

    Mark Beaman; William Wade McGee

    Uranium and its associated trace elements and radionuclides are ubiquitous in the South Texas Tertiary environment. Surface mining of this resource from the 1960s through the early 1980s at over sixty locations has left an extensive anthropological footprint (Fig. 1) in the lower Nueces and San Antonio river basins. Reclamation of mining initiated after 1975 has been under the regulatory

  14. National Uranium Resource Evaluation: Marfa Quadrangle, Texas

    SciTech Connect

    Henry, C D; Duex, T W; Wilbert, W P

    1982-09-01

    The uranium favorability of the Marfa 1/sup 0/ by 2/sup 0/ Quadrangle, Texas, was evaluated in accordance with criteria established for the National Uranium Resource Evaluation. Surface and subsurface studies, to a 1500 m (5000 ft) depth, and chemical, petrologic, hydrogeochemical, and airborne radiometric data were employed. The entire quadrangle is in the Basin and Range Province and is characterized by Tertiary silicic volcanic rocks overlying mainly Cretaceous carbonate rocks and sandstones. Strand-plain sandstones of the Upper Cretaceous San Carlos Formation and El Picacho Formation possess many favorable characteristics and are tentatively judged as favorable for sandstone-type deposits. The Tertiary Buckshot Ignimbrite contains uranium mineralization at the Mammoth Mine. This deposit may be an example of the hydroauthigenic class; alternatively, it may have formed by reduction of uranium-bearing ground water produced during diagenesis of tuffaceous sediments of the Vieja Group. Although the presence of the deposit indicates favorability, the uncertainty in the process that formed the mineralization makes delineation of a favorable environment or area difficult. The Allen intrusions are favorable for authigenic deposits. Basin fill in several bolsons possesses characteristics that suggest favorability but which are classified as unevaluated because of insufficient data. All Precambrian, Paleozoic, other Mesozoic, and other Cenozoic environments are unfavorable.

  15. The multiphoton ionization of uranium hexafluoride

    SciTech Connect

    Armstrong, D.P. (Oak Ridge K-25 Site, TN (United States). UEO Enrichment Technical Operations Div.)

    1992-05-01

    Multiphoton ionization (MPI) time-of-flight mass spectroscopy and photoelectron spectroscopy studies of UF{sub 6} have been conducted using focused light from the Nd:YAG laser fundamental ({lambda}=1064 nm) and its harmonics ({lambda}=532, 355, or 266 nm), as well as other wavelengths provided by a tunable dye laser. The MPI mass spectra are dominated by the singly and multiply charged uranium ions rather than by the UF{sub x}{sup +} fragment ions even at the lowest laser power densities at which signal could be detected. The laser power dependence of U{sup n+} ions signals indicates that saturation can occur for many of the steps required for their ionization. In general, the doubly-charged uranium ion (U{sup 2+}) intensity is much greater than that of the singly-charged uranium ion (U{sup +}). For the case of the tunable dye laser experiments, the U{sup n+} (n = 1- 4) wavelength dependence is relatively unstructured and does not show observable resonance enhancement at known atomic uranium excitation wavelengths. The dominance of the U{sup 2+} ion and the absence or very small intensities of UF{sub x}{sup +} fragments, along with the unsaturated wavelength dependence, indicate that mechanisms may exist other than ionization of bare U atoms after the stepwise photodissociation of F atoms from the parent molecule.

  16. Thermophysical properties of gas phase uranium tetrafluoride

    NASA Technical Reports Server (NTRS)

    Watanabe, Yoichi; Anghaie, Samim

    1993-01-01

    Thermophysical data of gaseous uranium tetrafluoride (UF4) are theoretically obtained by taking into account dissociation of molecules at high temperatures (2000-6000 K). Determined quantities include specific heat, optical opacity, diffusion coefficient, viscosity, and thermal conductivity. A computer program is developed for the calculation.

  17. Uranium on the Checkerboard: Crisis at Crownpoint

    ERIC Educational Resources Information Center

    Barry, Tom; Wood, Beth

    1978-01-01

    Some 22 companies are currently exploring for uranium in the Crownpoint, New Mexico area. Due to complicated patterns of land and mineral ownership on the Navajo Reservation, the mining companies do not feel obligated to communicate, and the Navajo are, consequently, worried about their social and physical environment. (JC)

  18. Radiological aspects of in situ uranium recovery

    SciTech Connect

    BROWN, STEVEN H. [SHB INC., 7505 S. Xanthia Place, Centennial, Colorado (United States)

    2007-07-01

    In the last few years, there has been a significant increase in the demand for Uranium as historical inventories have been consumed and new reactor orders are being placed. Numerous mineralized properties around the world are being evaluated for Uranium recovery and new mining / milling projects are being evaluated and developed. Ore bodies which are considered uneconomical to mine by conventional methods such as tunneling or open pits, can be candidates for non-conventional recovery techniques, involving considerably less capital expenditure. Technologies such as Uranium in situ leaching in situ recovery (ISL / ISR), have enabled commercial scale mining and milling of relatively small ore pockets of lower grade, and may make a significant contribution to overall world wide uranium supplies over the next ten years. Commercial size solution mining production facilities have operated in the US since 1975. Solution mining involves the pumping of groundwater, fortified with oxidizing and complexing agents into an ore body, solubilizing the uranium in situ, and then pumping the solutions to the surface where they are fed to a processing plant. Processing involves ion exchange and may also include precipitation, drying or calcining and packaging operations depending on facility specifics. This paper presents an overview of the ISR process and the health physics monitoring programs developed at a number of commercial scale ISL / ISR Uranium recovery and production facilities as a result of the radiological character of these processes. Although many radiological aspects of the process are similar to that of conventional mills, conventional-type tailings as such are not generated. However, liquid and solid byproduct materials may be generated and impounded. The quantity and radiological character of these by products are related to facility specifics. Some special monitoring considerations are presented which are required due to the manner in which Radon gas is evolved in the process and the unique aspects of controlling solution flow patterns underground. An overview of the major aspects of the health physics and radiation protection programs that were developed at these facilities are discussed and contrasted to circumstances of the current generation and state of the art of Uranium ISR technologies and facilities. (authors)

  19. Uranium dynamics and developmental sensitivity in rat kidney.

    PubMed

    Homma-Takeda, Shino; Kokubo, Toshiaki; Terada, Yasuko; Suzuki, Kyoko; Ueno, Shunji; Hayao, Tatsuo; Inoue, Tatsuya; Kitahara, Keisuke; Blyth, Benjamin J; Nishimura, Mayumi; Shimada, Yoshiya

    2013-07-01

    Renal toxicity is the principal health concern after uranium exposure. Children are particularly vulnerable to uranium exposure; with contact with depleted uranium in war zones or groundwater contamination the most likely exposure scenarios. To investigate renal sensitivity to uranium exposure during development, we examined uranium distribution and uranium-induced apoptosis in the kidneys of neonate (7-day-old), prepubertal (25-day-old) and adult (70-day-old) male Wistar rats. Mean renal uranium concentrations increased with both age-at-exposure and exposure level after subcutaneous administration of uranium acetate (UA) (0.1-2 mg kg(-1) body weight). Although less of the injected uranium was deposited in the kidneys of the two younger rat groups, the proportion of the peak uranium content remaining in the kidneys after 2 weeks declined with age-at-exposure, suggesting reduced clearance in younger animals. In situ high-energy synchrotron radiation X-ray fluorescence analysis revealed site-specific accumulation of uranium in the S3 segment of the proximal tubules, distributed in the inner cortex and outer stripe of the outer medulla. Apoptosis and cell loss in the proximal tubules increased with age-at-exposure to 0.5 mg kg(-1) UA. Surprisingly, prepubertal rats were uniquely sensitive to uranium-induced lethality from the higher exposure levels. Observations of increased apoptosis in generating/re-generating tubules particularly in prepubertal rats could help to explain their high mortality rate. Together, our findings suggest that age-at-exposure and exposure level are important parameters for uranium toxicity; uranium tends to persist in developing kidneys after low-level exposures, although renal toxicity is more pronounced in adults. PMID:23619997

  20. Uranium Sequestration by Aluminum Phosphate Minerals in Unsaturated Soils

    SciTech Connect

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

    2007-07-01

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

  1. Chemical Equilibrium of the Dissolved Uranium in Groundwaters From a Spanish Uranium-Ore Deposit

    SciTech Connect

    Garralon, Antonio; Gomez, Paloma; Turrero, Maria Jesus; Buil, Belen; Sanchez, Lorenzo [Departamento de Medio Ambiente, CIEMAT, Avda. Complutense 22. Edificio 19, Madrid, 28040 (Spain)

    2007-07-01

    The main objectives of this work are to determine the hydrogeochemical evolution of an uranium ore and identify the main water/rock interaction processes that control the dissolved uranium content. The Mina Fe uranium-ore deposit is the most important and biggest mine worked in Spain. Sageras area is located at the north part of the Mina Fe, over the same ore deposit. The uranium deposit was not mined in Sageras and was only perturbed by the exploration activities performed 20 years ago. The studied area is located 10 Km northeast of Ciudad Rodrigo (Salamanca) at an altitude over 650 m.a.s.l. The uranium mineralization is related to faults affecting the metasediments of the Upper Proterozoic to Lower Cambrian schist-graywacke complex (CEG), located in the Centro-Iberian Zone of the Hesperian Massif . The primary uranium minerals are uraninite and coffinite but numerous secondary uranium minerals have been formed as a result of the weathering processes: yellow gummite, autunite, meta-autunite, torbernite, saleeite, uranotile, ianthinite and uranopilite. The water flow at regional scale is controlled by the topography. Recharge takes place mainly in the surrounding mountains (Sierra Pena de Francia) and discharge at fluvial courses, mainly Agueda and Yeltes rivers, boundaries S-NW and NE of the area, respectively. Deep flows (lower than 100 m depth) should be upwards due to the river vicinity, with flow directions towards the W, NW or N. In Sageras-Mina Fe there are more than 100 boreholes drilled to investigate the mineral resources of the deposit. 35 boreholes were selected in order to analyze the chemical composition of groundwaters based on their depth and situation around the uranium ore. Groundwater samples come from 50 to 150 m depth. The waters are classified as calcium-bicarbonate type waters, with a redox potential that indicates they are slightly reduced (values vary between 50 to -350 mV). The TOC varies between <0.1 and 4.0 mgC/L and the dissolved uranium has a maximum value of 7.7 mg/L. According the analytical data of dissolved uranium, the mineral closest to equilibrium seems to be UO{sub 2}(am). The tritium contents in the groundwaters vary between 1.5 and 7.3 T.U. Considering that the mean value of tritium in rainwater from the studied area has a value of 4 T.U., it can be concluded that the residence times of the groundwaters are relatively short, not longer than 50 years in the oldest case. (authors)

  2. US Transuranium and Uranium Registries case study on accidental exposure to uranium hexafluoride.

    PubMed

    Avtandilashvili, Maia; Puncher, Matthew; McComish, Stacey L; Tolmachev, Sergei Y

    2015-03-01

    The United States Transuranium and Uranium Registries' (USTUR) whole-body donor (Case 1031) was exposed to an acute inhalation of uranium hexafluoride (UF6) produced from an explosion at a uranium processing plant 65?years prior to his death. The USTUR measurements of tissue samples collected at the autopsy indicated long-term retention of inhaled slightly enriched uranium material (0.85% (235)U) in the deep lungs and thoracic lymph nodes. In the present study, the authors combined the tissue measurement results with historical bioassay data, and analysed them with International Commission on Radiological Protection (ICRP) respiratory tract models and the ICRP Publication 69 systemic model for uranium using maximum likelihood and Bayesian statistical methods. The purpose of the analysis was to estimate intakes and model parameter values that best describe the data, and evaluate their effect on dose assessment. The maximum likelihood analysis, which used the ICRP Publication 66 human respiratory tract model, resulted in a point estimate of 79?mg of uranium for the occupational intake composed of 86% soluble, type F material and 14% insoluble, type S material. For the Bayesian approach, the authors applied the Markov Chain Monte Carlo method, but this time used the revised human respiratory tract model, which is currently being used by ICRP to calculate new dose coefficients for workers. The Bayesian analysis estimated that the mean uranium intake was 160?mg, and calculated the case-specific lung dissolution parameters with their associated uncertainties. The parameters were consistent with the inhaled uranium material being predominantly soluble with a small but significant insoluble component. The 95% posterior range of the rapid dissolution fraction (the fraction of deposited material that is absorbed to blood rapidly) was 0.12 to 0.91 with a median of 0.37. The remaining fraction was absorbed slowly, with a 95% range of 0.000?22?d(-1) to 0.000?36?d(-1) and a median of 0.000?31?d(-1). The effective dose per unit intake calculated using the dissolution parameters derived from the maximum likelihood and the Bayesian analyses was higher than the current ICRP dose coefficient for type F uranium by a factor of 2 or 7, respectively; the higher value of the latter was due to use of the revised respiratory tract model. The dissolution parameter values obtained here may be more appropriate to use for radiation protection purposes when individuals are exposed to a UF6 mixture that contains an insoluble uranium component. PMID:25580579

  3. Throughput limitations and pressure relief of the OSUR (Onsite Uranium Recycle) semiworks off-gas system

    Microsoft Academic Search

    1986-01-01

    The Robotics and Fabrication Technology Division operates the Onsite Uranium Recycle (OSUR) semiworks to develop equipment for a uranium conversion process. The process converts uranyl nitrate solution to uranium oxide powder by loading the uranium on ion exchange resin and then burning the resin. With proper loading and burning conditions, the uranium oxide ash is suitable for blending with aluminum

  4. [Internal contamination with depleted uranium and health disorders].

    PubMed

    Pranji?, Nurka; Karamehi?, Jasenko; Ljuca, Farid; Zigi?, Zlata; Asceri?, Mensura

    2002-01-01

    In this review we used the published data on depleted uranium (experimental and epidemiological) from the current literature. Depleted uranium is a toxic heavy metal that in high dose may cause poisoning and health effects as those caused by lead, mercury, and chromium. It is slightly radioactive. The aim of this review was to select, to arrange, to present references of scientific papers, and to summarise the data in order to give a comprehensive image of the results of toxicological studies on depleted uranium that have been done on animals (including carcinogenic activity). We have also used epidemiological posted study results related to occupational and environmental exposure to depleted uranium. The toxicity of uranium has been studied extensively. The results of the studies indicated primarily its chemical toxicity, particularly renal effects, but depleted uranium is not radiological hazard. Uranium is not metal determined to be carcinogenic (the International Agency of Research on Cancer). The military use of depleted uranium will give additional insight into the toxicology of depleted uranium. The present controversy over the radiological and chemical toxicity of depleted uranium used in the Gulf War requests further experimental and clinical investigations of its effects on the biosphere and human beings. PMID:11917690

  5. Effectiveness of chelation therapy with time after acute uranium intoxication.

    PubMed

    Domingo, J L; Ortega, A; Llobet, J M; Corbella, J

    1990-01-01

    The effect of increasing the time interval between acute uranium exposure and chelation therapy was studied in male Swiss mice. Gallic acid, 4,5-dihydroxy-1,3- benzenedisulfonic acid (Tiron), diethylenetriaminepentaacetic acid (DTPA), and 5-aminosalicylic acid (5-AS) were administered ip at 0, 0.25, 1, 4, and 24 hr after sc injection of 10 mg/kg of uranyl acetate dihydrate. Chelating agents were given at doses equal to one-fourth of their respective LD50 values. Daily elimination of uranium into urine and feces was determined for 4 days after which time the mice were killed, and the concentration of uranium was measured in kidney, spleen, and bone. The excretion of uranium was especially rapid in the first 24 hr. Treatment with Tiron or gallic acid at 0, 0.25, or 1 hr after uranium exposure significantly increased the total excretion of the metal. In kidney and bone, only administration of Tiron at 0, 0.25, or 1 hr after uranium injection, or gallic acid at 1 hr after uranium exposure significantly reduced tissue uranium concentrations. Treatment at later times (4 to 24 hr) did not increase the total excretion of the metal and did not decrease the tissue uranium concentrations 4 days after uranyl acetate administration. The results show that the length of time before initiating chelation therapy for acute uranium intoxication greatly influences the effectiveness of this therapy. PMID:2307325

  6. Fermentation and Hydrogen Metabolism Affect Uranium Reduction by Clostridia

    DOE PAGESBeta

    Gao, Weimin; Francis, Arokiasamy J.

    2013-01-01

    Previously, it has been shown that not only is uranium reduction under fermentation condition common among clostridia species, but also the strains differed in the extent of their capability and the pH of the culture significantly affected uranium(VI) reduction. In this study, using HPLC and GC techniques, metabolic properties of those clostridial strains active in uranium reduction under fermentation conditions have been characterized and their effects on capability variance of uranium reduction discussed. Then, the relationship between hydrogen metabolism and uranium reduction has been further explored and the important role played by hydrogenase in uranium(VI) and iron(III) reduction by clostridiamore »demonstrated. When hydrogen was provided as the headspace gas, uranium(VI) reduction occurred in the presence of whole cells of clostridia. This is in contrast to that of nitrogen as the headspace gas. Without clostridia cells, hydrogen alone could not result in uranium(VI) reduction. In alignment with this observation, it was also found that either copper(II) addition or iron depletion in the medium could compromise uranium reduction by clostridia. In the end, a comprehensive model was proposed to explain uranium reduction by clostridia and its relationship to the overall metabolism especially hydrogen (H2) production.« less

  7. Neurological effects of acute uranium exposure with and without stress.

    PubMed

    Barber, D S; Hancock, S K; McNally, A M; Hinckley, J; Binder, E; Zimmerman, K; Ehrich, M F; Jortner, B S

    2007-11-01

    Circulating uranium rapidly enters the brain and may cause adverse effects on the nervous system that are potentially modulated by stress. In this study, the neurological effects of a single intramuscular injection of 0, 0.1, 0.3, or 1 mg uranium/kg (as uranyl acetate, UA) in rats were examined in the presence and absence of stress. Treatment with UA produced time and dose-dependent increases in serum and regional brain uranium levels. While serum levels returned to control levels by day 30, brain levels remained elevated. Application of stress did not affect the distribution or retention of uranium. Exposure to 1 mg U/kg significantly decreased ambulatory activity, weight gain, forelimb grip strength and transiently impaired working memory. Effects on grip strength and memory were prevented by application of stress prior to uranium exposure. Striatal dopamine content was reduced by 30% 3 days after treatment with 1mg/kg (59+/-6 nmol/mg tissue versus 41+/-5 nmol/mg tissue), but levels returned to control 7 days after uranium exposure. The effect on dopamine was ameliorated by prior application of stress. Exposure to UA did not alter 3,4 dihydroxyphenylacetic acid (DOPAC) levels or numbers of D2 receptors in the striatum. No effect of uranium or stress was observed on levels of GABA, serotonin, norepinephrine, or glutathione (GSH) in the striatum, hippocampus, cerebellum, or cortex. These results indicate that single intramuscular exposures to uranium produce sustained elevation of brain uranium levels and at doses above 0.3 mg/kg can have adverse neurological effects. Application of stress prior to uranium administration modulates neurological effects, but the mechanism is not due to effects on uranium distribution. Uranium exposure also produced renal toxicity which must be considered to accurately assess the effects of uranium on neurological function. PMID:17669499

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

    SciTech Connect

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

    1983-04-01

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

  9. Uranium provinces of North America; their definition, distribution, and models

    USGS Publications Warehouse

    Finch, Warren Irvin

    1996-01-01

    Uranium resources in North America are principally in unconformity-related, quartz-pebble conglomerate, sandstone, volcanic, and phosphorite types of uranium deposits. Most are concentrated in separate, well-defined metallogenic provinces. Proterozoic quartz-pebble conglomerate and unconformity-related deposits are, respectively, in the Blind River?Elliot Lake (BRELUP) and the Athabasca Basin (ABUP) Uranium Provinces in Canada. Sandstone uranium deposits are of two principal subtypes, tabular and roll-front. Tabular sandstone uranium deposits are mainly in upper Paleozoic and Mesozoic rocks in the Colorado Plateau Uranium Province (CPUP). Roll-front sandstone uranium deposits are in Tertiary rocks of the Rocky Mountain and Intermontane Basins Uranium Province (RMIBUP), and in a narrow belt of Tertiary rocks that form the Gulf Coastal Uranium Province (GCUP) in south Texas and adjacent Mexico. Volcanic uranium deposits are concentrated in the Basin and Range Uranium Province (BRUP) stretching from the McDermitt caldera at the Oregon-Nevada border through the Marysvale district of Utah and Date Creek Basin in Arizona and south into the Sierra de Pe?a Blanca District, Chihuahua, Mexico. Uraniferous phosphorite occurs in Tertiary sediments in Florida, Georgia, and North and South Carolina and in the Lower Permian Phosphoria Formation in Idaho and adjacent States, but only in Florida has economic recovery been successful. The Florida Phosphorite Uranium Province (FPUP) has yielded large quantities of uranium as a byproduct of the production of phosphoric acid fertilizer. Economically recoverable quantities of copper, gold, molybdenum, nickel, silver, thorium, and vanadium occur with the uranium deposits in some provinces. Many major epochs of uranium mineralization occurred in North America. In the BRELUP, uranium minerals were concentrated in placers during the Early Proterozoic (2,500?2,250 Ma). In the ABUP, the unconformity-related deposits were most likely formed initially by hot saline formational water related to diagenesis (?1,400 to 1,330 Ma) and later reconcentrated by hydrothermal events at ?1,280??1,000, ?575, and ?225 Ma. Subsequently in North America, only minor uranium mineralization occurred until after continental collision in Permian time (255 Ma). Three principal epochs of uranium mineralization occurred in the CPUP: (1) ??210?200 Ma, shortly after Late Triassic sedimentation; (2) ??155?150 Ma, in Late Jurassic time; and (3) ??135 Ma, after sedimentation of the Upper Jurassic Morrison Formation. The most likely source of the uranium was silicic volcaniclastics for the three epochs derived from a volcanic island arc at the west edge of the North American continent. Uranium mineralization occurred during Eocene, Miocene, and Pliocene times in the RMIBUP, GCUP, and BRUP. Volcanic activity took place near the west edge of the continent during and shortly after sedimentation of the host rocks in these three provinces. Some volcanic centers in the Sierra de Pe?a Blanca district within the BRUP may have provided uranium-rich ash to host rocks in the GCUP. Most of the uranium provinces in North America appear to have a common theme of close associations to volcanic activity related to the development of the western margin of the North American plate. The south and west margin of the Canadian Shield formed the leading edge of the progress of uranium source development and mineralization from the Proterozoic to the present. The development of favorable hosts and sources of uranium is related to various tectonic elements developed over time. Periods of major uranium mineralization in North America were Early Proterozoic, Middle Proterozoic, Late Triassic?Early Jurassic, Early Cretaceous, Oligocene, and Miocene. Tertiary mineralization was the most pervasive, covering most of Western and Southern North America.

  10. Uranium-Loaded Water Treatment Resins: 'Equivalent Feed' at NRC and Agreement State-Licensed Uranium Recovery Facilities - 12094

    SciTech Connect

    Camper, Larry W.; Michalak, Paul; Cohen, Stephen; Carter, Ted [Nuclear Regulatory Commission (United States)

    2012-07-01

    Community Water Systems (CWSs) are required to remove uranium from drinking water to meet EPA standards. Similarly, mining operations are required to remove uranium from their dewatering discharges to meet permitted surface water discharge limits. Ion exchange (IX) is the primary treatment strategy used by these operations, which loads uranium onto resin beads. Presently, uranium-loaded resin from CWSs and mining operations can be disposed as a waste product or processed by NRC- or Agreement State-licensed uranium recovery facilities if that licensed facility has applied for and received permission to process 'alternate feed'. The disposal of uranium-loaded resin is costly and the cost to amend a uranium recovery license to accept alternate feed can be a strong disincentive to commercial uranium recovery facilities. In response to this issue, the NRC issued a Regulatory Issue Summary (RIS) to clarify the agency's policy that uranium-loaded resin from CWSs and mining operations can be processed by NRC- or Agreement State-licensed uranium recovery facilities without the need for an alternate feed license amendment when these resins are essentially the same, chemically and physically, to resins that licensed uranium recovery facilities currently use (i.e., equivalent feed). NRC staff is clarifying its current alternate feed policy to declare IX resins as equivalent feed. This clarification is necessary to alleviate a regulatory and financial burden on facilities that filter uranium using IX resin, such as CWSs and mine dewatering operations. Disposing of those resins in a licensed facility could be 40 to 50 percent of the total operations and maintenance (O and M) cost for a CWS. Allowing uranium recovery facilities to treat these resins without requiring a license amendment lowers O and M costs and captures a valuable natural resource. (authors)

  11. Comparative extraction efficiencies of tri- n -butyl phosphate and N,N -dihexyloctanamide for uranium recovery using supercritical CO 2

    Microsoft Academic Search

    A. S. Kanekar; P. N. Pathak; P. K. Mohapatra; V. K. Manchanda

    2010-01-01

    Extraction of uranium from tissue paper, synthetic soil, and from its oxides (UO2, UO3 and U3O8) was carried out using supercritical carbon dioxide modified with methanol solutions of extractants such as tri-n-butyl phosphate (TBP) or N,N-dihexyl octanamide (DHOA). The effects of temperature, pressure, extractant\\/nitric acid (nitrate) concentration, and of hydrogen\\u000a peroxide on uranium extraction were investigated. The dissolution and extraction

  12. In-line assay monitor for uranium hexafluoride

    DOEpatents

    Wallace, S.A.

    1980-03-21

    An in-line assay monitor for determining the content of uranium-235 in a uranium hexafluoride gas isotopic separation system is provided which removes the necessity of complete access to the operating parameters of the system for determining the uranium-235 content. The method and monitor for carrying out the method involve cooling of a radiation pervious chamber connected in fluid communication with the selected point in the system to withdraw a specimen and solidify the specimen in the chamber. The specimen is irradiated by means of an ionizing radiation source of energy different from that of the 185 keV gamma emissions from uranium-235. The uranium-235 content of the specimen is determined from comparison of the accumulated 185 keV energy counts and reference energy counts. The latter is used to measure the total uranium isotopic content of the specimen.

  13. The uranium cylinder assay system for enrichment plant safeguards

    SciTech Connect

    Miller, Karen A [Los Alamos National Laboratory; Swinhoe, Martyn T [Los Alamos National Laboratory; Marlow, Johnna B [Los Alamos National Laboratory; Menlove, Howard O [Los Alamos National Laboratory; Rael, Carlos D [Los Alamos National Laboratory; Iwamoto, Tomonori [JNFL; Tamura, Takayuki [JNFL; Aiuchi, Syun [JNFL

    2010-01-01

    Safeguarding sensitive fuel cycle technology such as uranium enrichment is a critical component in preventing the spread of nuclear weapons. A useful tool for the nuclear materials accountancy of such a plant would be an instrument that measured the uranium content of UF{sub 6} cylinders. The Uranium Cylinder Assay System (UCAS) was designed for Japan Nuclear Fuel Limited (JNFL) for use in the Rokkasho Enrichment Plant in Japan for this purpose. It uses total neutron counting to determine uranium mass in UF{sub 6} cylinders given a known enrichment. This paper describes the design of UCAS, which includes features to allow for unattended operation. It can be used on 30B and 48Y cylinders to measure depleted, natural, and enriched uranium. It can also be used to assess the amount of uranium in decommissioned equipment and waste containers. Experimental measurements have been carried out in the laboratory and these are in good agreement with the Monte Carlo modeling results.

  14. Reductive dissolution approaches to removal of uranium from contaminated soils

    SciTech Connect

    Brainard, J.R.; Iams, H.D.; Strietelmeier, B.A.; Del-Rio Garcia, M.

    1994-06-01

    Traditional approaches to uranium recovery from ores have employed oxidation of U(IV) minerals to form the uranyl cation which is subsequently complexed by carbonate or maintained in solution by strong acids. Reductive approaches for uranium decontamination have been limited to removing soluble uranium from solutions by formation of U{sup 4+} which readily hydrolyses and precipitates. As part of the Uranium in Soils Integrated Demonstration, we have developed a reductive approach to solubilization of uranium from contaminated soils which employs reduction to destabilize U(VI) solid and sorbed species, and strong chelators for U(IV) to prevent hydrolysis and solubilize the reduced from. This strategy has particular application to sites where the uranium is present primarily as intractable U(VI) phases and where high fractions of the contamination must be removed to meet regulatory requirements.

  15. Measurements of uranium mass confined in high density plasmas

    NASA Technical Reports Server (NTRS)

    Stoeffler, R. C.

    1976-01-01

    An X-ray absorption method for measuring the amount of uranium confined in high density, rf-heated uranium plasmas is described. A comparison of measured absorption of 8 keV X-rays with absorption calculated using Beer Law indicated that the method could be used to measure uranium densities from 3 times 10 to the 16th power atoms/cu cm to 5 times 10 to the 18th power atoms/cu cm. Tests were conducted to measure the density of uranium in an rf-heated argon plasma with UF6 infection and with the power to maintain the discharge supplied by a 1.2 MW rf induction heater facility. The uranium density was measured as the flow rate through the test chamber was varied. A maximum uranium density of 3.85 times 10 to the 17th power atoms/cu cm was measured.

  16. National Uranium Resource Evaluation: Presido Quadrangle, Texas

    SciTech Connect

    Duex, T.W.; Henry, C.D.; Wilbert, W.P.

    1982-09-01

    The uranium potential of the Presidio 1/sup 0/ by 2/sup 0/ Quadrangle, Texas, was evaluated using criteria developed for the National Uranium Resource Evaluation program. Surface and subsurface studies (to 1500 m) were employed, as were chemical, petrologic, hydrogeochemical, and airborne radiometric data (8-km spacing). The entire quadrangle is in the Basin and Range Province and is characterized by Tertiary silicic volcanic rocks and tuffaceous sediments, which overlie chiefly Cretaceous carbonate rocks. Favorable environments include the Allen Intrusions, a group of rhyolite domes that contain authigenic deposits, and Cienega Mountain, a homogeneous riebeckite rhyolite intrusion that could contain subeconomic orthomagmatic deposits. Bolson fill exhibits several characteristics that suggest it could be favorable; however, insufficient information is available for complete evaluation. Well control is sparse; several subsurface environments are judged unfavorable, chiefly by analogy with adjacent quadrangles and by projection of unfavorable outcropping rocks.

  17. Uranium enrichment management review: summary of analysis

    SciTech Connect

    Not Available

    1981-01-01

    In May 1980, the Assistant Secretary for Resource Applications within the Department of Energy requested that a group of experienced business executives be assembled to review the operation, financing, and management of the uranium enrichment enterprise as a basis for advising the Secretary of Energy. After extensive investigation, analysis, and discussion, the review group presented its findings and recommendations in a report on December 2, 1980. The following pages contain background material on which that final report was based. This report is arranged in chapters that parallel those of the uranium enrichment management review final report - chapters that contain summaries of the review group's discussion and analyses in six areas: management of operations and construction; long-range planning; marketing of enrichment services; financial management; research and development; and general management. Further information, in-depth analysis, and discussion of suggested alternative management practices are provided in five appendices.

  18. Uranium settling rates in SRS waste supernate

    SciTech Connect

    Karraker, D.G.

    1994-01-26

    The evaporation of SRS High Level Waste supernate is accompanied by a decrease in the solubility of uranium, and thus uranium precipitates as the complex compound usually referred to as Na{sub 2}U{sub 2}O{sub 7}. The precipitated Na{sub 2}U{sub 2}O{sub 7} and other precipitated solids will settle through the concentrated evaporator product at a rate determined by Stokes` Law. The quantities which make up Stokes` Law can all be determined from physical measurements, and the settling rate thus determined for any particle size or, by extension, for a distribution of particle sizes. Reported here are the measurement of the variables in Stokes` Law for Na{sub 2}U{sub 2}O{sub 7}.

  19. Uranium series dating of Allan Hills ice

    NASA Technical Reports Server (NTRS)

    Fireman, E. L.

    1986-01-01

    Uranium-238 decay series nuclides dissolved in Antarctic ice samples were measured in areas of both high and low concentrations of volcanic glass shards. Ice from the Allan Hills site (high shard content) had high Ra-226, Th-230 and U-234 activities but similarly low U-238 activities in comparison with Antarctic ice samples without shards. The Ra-226, Th-230 and U-234 excesses were found to be proportional to the shard content, while the U-238 decay series results were consistent with the assumption that alpha decay products recoiled into the ice from the shards. Through this method of uranium series dating, it was learned that the Allen Hills Cul de Sac ice is approximately 325,000 years old.

  20. Plutonium Uranium Extraction Facility Documented Safety Analysis

    SciTech Connect

    DODD, E.N.

    2003-10-08

    This document provides the documented safety analysis (DSA) and Central Plateau Remediation Project (CP) requirements that apply to surveillance and maintenance (S&M) activities at the Plutonium-Uranium Extraction (PUREX) facility. This DSA was developed in accordance with DOE-STD-1120-98, ''Integration of Environment, Safety, and Health into Facility Disposition Activities''. Upon approval and implementation of this document, the current safety basis documents will be retired.

  1. The Frontiers of Uranium-series Research

    NASA Astrophysics Data System (ADS)

    Handley, Heather; Turner, Simon

    2014-05-01

    Scientists working on uranium (U)-series isotopes in igneous and sedimentary systems came together for a symposium in mid-February. The overall objectives of the symposium were to advance understanding of the timescales of magmatic and sedimentary processes and to identify key scientific and analytical future research directions. Twenty-nine participants from 16 institutions attended the symposium. The keynote speakers were Kari Cooper (University of California, Davis), Francois Chabaux (University of Strasbourg), and Ken Sims (University of Wyoming).

  2. Uranio impoverito: perché? (Depleted uranium: why?)

    E-print Network

    Germano D'Abramo

    2003-06-05

    In this paper we develop a simple model of the penetration process of a long rod through an uniform target. Applying the momentum and energy conservation laws, we derive an analytical relation which shows how the penetration depth depends upon the density of the rod, given a fixed kinetic energy. This work was sparked off by the necessity of understanding the effectiveness of high density penetrators (e.g. depleted uranium penetrators) as anti-tank weapons.

  3. The ultimate disposition of depleted uranium

    SciTech Connect

    Not Available

    1990-12-01

    Significant amounts of the depleted uranium (DU) created by past uranium enrichment activities have been sold, disposed of commercially, or utilized by defense programs. In recent years, however, the demand for DU has become quite small compared to quantities available, and within the US Department of Energy (DOE) there is concern for any risks and/or cost liabilities that might be associated with the ever-growing inventory of this material. As a result, Martin Marietta Energy Systems, Inc. (Energy Systems), was asked to review options and to develop a comprehensive plan for inventory management and the ultimate disposition of DU accumulated at the gaseous diffusion plants (GDPs). An Energy Systems task team, under the chairmanship of T. R. Lemons, was formed in late 1989 to provide advice and guidance for this task. This report reviews options and recommends actions and objectives in the management of working inventories of partially depleted feed (PDF) materials and for the ultimate disposition of fully depleted uranium (FDU). Actions that should be considered are as follows. (1) Inspect UF{sub 6} cylinders on a semiannual basis. (2) Upgrade cylinder maintenance and storage yards. (3) Convert FDU to U{sub 3}O{sub 8} for long-term storage or disposal. This will include provisions for partial recovery of costs to offset those associated with DU inventory management and the ultimate disposal of FDU. Another recommendation is to drop the term tails'' in favor of depleted uranium'' or DU'' because the tails'' label implies that it is waste.'' 13 refs.

  4. Magnetic relaxation in uranium ferromagnetic superconductors

    NASA Astrophysics Data System (ADS)

    Mineev, V. P.

    2013-12-01

    There is proposed a phenomenological description of quasielastic neutron scattering in the ferromagnetic metals UGe2 and UCoGe based on their property that magnetization supported by the moments located at uranium atoms is not a conserved quantity relaxing to equilibrium by the interaction with an itinerant electron subsystem. As a result the linewidth of quasielastic neutron scattering at q?0 acquires nonvanishing value at all temperatures but the Curie temperature.

  5. Biosorption of uranium on Sargassum biomass

    Microsoft Academic Search

    Jinbai Yang; Bohumil Volesky

    1999-01-01

    Protonated, non-living biomass of the brown alga Sargassum fluitans effectively sequestered uranyl ions from aqueous solution, with the maximum uranium sorption capacity exceeding 560mg\\/g, 330mg\\/g and 150mg\\/g at pH 4.0, 3.2 and 2.6, respectively. At various pH levels, batch sorption equilibrium was reached within 3h and the sorption isotherms were interpreted in terms of the Langmuir model. The sorption system

  6. 75 FR 7525 - Application for a License To Export High-Enriched Uranium

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-19

    ...Application for a License To Export High-Enriched Uranium Pursuant to 10 CFR 110.70(c) ``Public notice...France; Belgium. Security Complex, February 2, Uranium (93.35%). uranium (87.3 elements in 2010, February 2,...

  7. 40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...description of the uranium, radium and vanadium...CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium...a) mines either open-pit or underground, from which uranium, radium and...

  8. 40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...description of the uranium, radium and vanadium...CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium...a) mines either open-pit or underground, from which uranium, radium and...

  9. 40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...description of the uranium, radium and vanadium...AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium...a) mines either open-pit or underground, from which uranium, radium and...

  10. 40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...description of the uranium, radium and vanadium...CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium...a) mines either open-pit or underground, from which uranium, radium and...

  11. 40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...description of the uranium, radium and vanadium...AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium...a) mines either open-pit or underground, from which uranium, radium and...

  12. 76 FR 71082 - Strata Energy, Inc., Ross Uranium Recovery Project; New Source Material License Application...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-16

    ...for the Ross Uranium Recovery Project to be located in Crook County...for the Ross Uranium Recovery Project, as required by Title 10 of the Code of Federal Regulations...to the Ross Uranium Recovery Project application, please...

  13. Plasma–Hydrogen Reduction of Waste Uranium Hexafluoride

    Microsoft Academic Search

    Yu. N. Tumanov; N. M. Trotsenko; A. V. Zagnit'ko; A. F. Galkin

    2001-01-01

    A technological scheme for plasma–hydrogen reduction of 235U waste uranium hexafluoride, producing metallic uranium and water-free hydrogen fluoride, is proposed. The results of experimental investigations of the basic stages of this technological scheme are examined: production of U–F–H plasma flow and production and separation of uranium melt and water-free hydrogen fluoride. The level of plasma and high-frequency technology for implementing

  14. Uranium recovery from coal ash dumps of Mongolia

    Microsoft Academic Search

    O. D. Maslov; Sh. Tserenpil; N. Norov; M. V. Gustova; M. F. Filippov; A. G. Belov; M. Altangerel; N. Enhbat

    2010-01-01

    The concentration of natural radionuclides and the feasibility of recovery of uranium from browncoal ash of a Mongolian cogeneration\\u000a plant were investigated. The concentrations of the elements were determined by instrumental gamma-activation (IGAA) and X-ray\\u000a fluorescence (XRF) analysis. Uranium from brown-coal ash was leached with an 8 M HNO3 + HF (10%) mixture. The extraction of uranium from the solution

  15. Irradiation Stability of Uranium Alloys at High Exposures

    SciTech Connect

    McDonell, W.R.

    2001-03-26

    Postirradiation examinations were begun of a series of unrestrained dilute uranium alloy specimens irradiated to exposures up to 13,000 MWD/T in NaK-containing stainless steel capsules. This test, part of a program of development of uranium metal fuels for desalination and power reactors sponsored by the Division of Reactor Development and Technology, has the objective of defining the temperature and exposure limits of swelling resistance of the alloyed uranium. This paper discusses those test results.

  16. Uranium Measurement Improvements at the Savannah River Technology Center

    SciTech Connect

    Shick, C. Jr.

    2002-02-13

    Uranium isotope ratio and isotope dilution methods by mass spectrometry are used to achieve sensitivity, precision and accuracy for various applications. This report presents recent progress made at SRTC in the analysis of minor isotopes of uranium. Comparison of routine measurements of NBL certified uranium (U005a) using the SRTC Three Stage Mass Spectrometer (3SMS) and the SRTC Single Stage Mass Spectrometer (SSMS). As expected, the three stage mass spectrometer yielded superior sensitivity, precision, and accuracy for this application.

  17. Thermodynamic properties of uranium in Ga-In based alloys

    NASA Astrophysics Data System (ADS)

    Volkovich, V. A.; Maltsev, D. S.; Yamshchikov, L. F.; Melchakov, S. Yu; Shchetinskiy, A. V.; Osipenko, A. G.; Kormilitsyn, M. V.

    2013-07-01

    Activity of uranium was determined in gallium, indium and gallium-indium eutectic (21.8 wt.% In) based alloys between 573 and 1073 K employing the electromotive force method. In two-phase U-Ga-In alloys, uranium forms the intermetallic compound UGa3. Activity coefficients and solubility of uranium in Ga-In eutectic were also determined in the same temperature range. Partial thermodynamic functions of ?-U in saturated alloys with gallium, indium and Ga-In eutectic were calculated.

  18. The Magnetic Susceptibilities of Palladium-Uranium Alloys

    Microsoft Academic Search

    L. F. Bates; S. J. Leach

    1956-01-01

    Measurements are made of the paramagnetic susceptibilities of palladium-uranium alloys covering the range of solid solution, of an intermetallic compound Pd3U and of specimens of very pure palladium and uranium over the temperature range 77° to 293°K. Increasing amounts of uranium cause a rapid decrease of susceptibility up to a concentration of 9 atomic per cent. Further increase in the

  19. Uranium concentration monitor manual: 2300 system

    SciTech Connect

    Russo, P.A.; Sprinkle, J.K. Jr.; Stephens, M.M.

    1985-04-01

    This manual describes the design, operation, and procedures for measurement control for the automated uranium concentration monitor on the 2300 solvent extraction system at the Oak Ridge Y-12 Plant. The nonintrusive monitor provides a near-real time readout of uranium concentration at two locations simultaneously in the solvent extraction system for process monitoring and control. Detectors installed at the top of the extraction column and at the bottom of the backwash column acquire spectra of gamma rays from the solvent extraction solutions in the columns. Pulse-height analysis of these spectra gives the concentration of uranium in the organic product of the extraction column and in the aqueous product of the solvent extraction system. The visual readouts of concentrations for process monitoring are updated every 2 min for both detection systems. Simultaneously, the concentration results are shipped to a remote computer that has been installed by Y-12 to demonstrate automatic control of the solvent extraction system based on input of near-real time process operation information. 8 refs., 13 figs., 4 tabs.

  20. Determination of uranium in natural waters

    USGS Publications Warehouse

    Barker, Franklin Butt; Johnson, J.O.; Edwards, K.W.; Robinson, B.P.

    1965-01-01

    A method is described for the determination of very low concentrations of uranium in water. The method is based on the fluorescence of uranium in a pad prepared by fusion of the dried solids from the water sample with a flux of 10 percent NaF 45.5 percent Na2CO3 , and 45.5 percent K2CO3 . This flux permits use of a low fusion temperature and yields pads which are easily removed from the platinum fusion dishes for fluorescence measurements. Uranium concentrations of less than 1 microgram per liter can be determined on a sample of 10 milliliters, or less. The sensitivity and accuracy of the method are dependent primarily on the purity of reagents used, the stability and linearity of the fluorimeter, and the concentration of quenching elements in the water residue. A purification step is recommended when the fluorescence is quenched by more than 30 percent. Equations are given for the calculation of standard deviations of analyses by this method. Graphs of error functions and representative data are also included.

  1. Critical analysis of world uranium resources

    USGS Publications Warehouse

    Hall, Susan; Coleman, Margaret

    2013-01-01

    The U.S. Department of Energy, Energy Information Administration (EIA) joined with the U.S. Department of the Interior, U.S. Geological Survey (USGS) to analyze the world uranium supply and demand balance. To evaluate short-term primary supply (0–15 years), the analysis focused on Reasonably Assured Resources (RAR), which are resources projected with a high degree of geologic assurance and considered to be economically feasible to mine. Such resources include uranium resources from mines currently in production as well as resources that are in the stages of feasibility or of being permitted. Sources of secondary supply for uranium, such as stockpiles and reprocessed fuel, were also examined. To evaluate long-term primary supply, estimates of uranium from unconventional and from undiscovered resources were analyzed. At 2010 rates of consumption, uranium resources identified in operating or developing mines would fuel the world nuclear fleet for about 30 years. However, projections currently predict an increase in uranium requirements tied to expansion of nuclear energy worldwide. Under a low-demand scenario, requirements through the period ending in 2035 are about 2.1 million tU. In the low demand case, uranium identified in existing and developing mines is adequate to supply requirements. However, whether or not these identified resources will be developed rapidly enough to provide an uninterrupted fuel supply to expanded nuclear facilities could not be determined. On the basis of a scenario of high demand through 2035, 2.6 million tU is required and identified resources in operating or developing mines is inadequate. Beyond 2035, when requirements could exceed resources in these developing properties, other sources will need to be developed from less well-assured resources, deposits not yet at the prefeasibility stage, resources that are currently subeconomic, secondary sources, undiscovered conventional resources, and unconventional uranium supplies. This report’s analysis of 141 mines that are operating or are being actively developed identifies 2.7 million tU of in-situ uranium resources worldwide, approximately 2.1 million tU recoverable after mining and milling losses were deducted. Sixty-four operating mines report a total of 1.4 million tU of in-situ RAR (about 1 million tU recoverable). Seventy-seven developing mines/production centers report 1.3 million tU in-situ Reasonably Assured Resources (RAR) (about 1.1 million tU recoverable), which have a reasonable chance of producing uranium within 5 years. Most of the production is projected to come from conventional underground or open pit mines as opposed to in-situ leach mines. Production capacity in operating mines is about 76,000 tU/yr, and in developing mines is estimated at greater than 52,000 tU/yr. Production capacity in operating mines should be considered a maximum as mines seldom produce up to licensed capacity due to operational difficulties. In 2010, worldwide mines operated at 70 percent of licensed capacity, and production has never exceeded 89 percent of capacity. The capacity in developing mines is not always reported. In this study 35 percent of developing mines did not report a target licensed capacity, so estimates of future capacity may be too low. The Organisation for Economic Co-operation and Development’s Nuclear Energy Agency (NEA) and International Atomic Energy Agency (IAEA) estimate an additional 1.4 million tU economically recoverable resources, beyond that identified in operating or developing mines identified in this report. As well, 0.5 million tU in subeconomic resources, and 2.3 million tU in the geologically less certain inferred category are identified worldwide. These agencies estimate 2.2 million tU in secondary sources such as government and commercial stockpiles and re-enriched uranium tails. They also estimate that unconventional uranium supplies (uraniferous phosphate and black shale deposits) may contain up to 7.6 million tU. Although unconventional resources are currently subeconomic, the improvement of extraction te

  2. Health concerns in uranium mining and milling

    SciTech Connect

    Archer, V.E.

    1981-07-01

    Mortality of uranium miners form both lung cancer and other respiratory diseases is strongly dependent on exposure to radon daughters, cigarette smoking and height. Lung cancer among 15 different mining groups (uranium, iron, led, zinc) was analyzed to determine what factors influence incidence and the induction-latent period. At low exposure or exposure rates, alpha radiation is more efficient in inducing lung cancer, producing an upward convex exposure-response curve. The induction-latent period is shortened by increased age at start of mining, by cigarette smoking and by high exposure rates. For a follow-up period of 20 to 25 years, the incidence increases with age at start of mining, with magnitude of exposure and with amount of cigarette smoking. Instead of extrapolating downward from high exposures to estimate risk at low levels, it is suggested that it might be more appropriate to use cancer rates associated with background radiation as the lowest point on the exposure-response curve. Although health risks are much greater in uranium mines than mills, there is some health risk in the mills from long-lived radioactive materials.

  3. National uranium resource evaluation: Mesa quaddrangle, Arizona

    SciTech Connect

    Luning, R.H.; Thiede, D.S.; O'Neill, A.J.; Nystrom, R.J.; White, D.L.

    1982-06-01

    The Mesa Quadrangle (2/sup 0/), Arizona, was evaluated to a depth of 1500 meters to identify geologic environments and delineate surface and subsurface areas favorable for the occurrence of uranium deposits. The criteria used to define uranium favorability were developed during the National Uranium Resource Evaluation program. Surface and subsurface studies were augmented by aerial radiometric surveys and hydrogeochemical and stream-sediment reconnaisance studies. The results of the investigations identified three favorable areas: older Precambrian quartz monzonite near Horseshoe Dam; the gray unit of the Dripping Spring quartzite of Precambrian age in the Sierra Ancha, Salt River Canyon, and Mescal Mountain regions; and Tertiary lake beds near Cave Creek, Horseshoe Dam, and northeastern Tonto Basin. Unfavorable environments include nearly all older Precambrian crystalline and metamorphic rocks, most younger Precambrian igneous and sedimentary rocks, parts of the Paleozoic section, igneous intrusives of Laramide age. Tertiary volcanic rocks, and late Tertiary sedimentary rocks. The eastern third of the quadrangle remains unevaluated because access was prohibited or could not be obtained in time. Environments were unevaluated in older Precambrian volcanic, sedimentary, and metamorphic rocks; the Naco and Supai Formations; Cretaceous sedimentary rocks; and many Tertiary sedimentary rocks in intermontane basins and within the southwestern portion of the quadrangle because of time constraints, land access restrictions, and sparsity of subsurface data.

  4. Dynamic strength of uranium at high temperatures

    NASA Astrophysics Data System (ADS)

    Zaretsky, E.; Herrmann, B.; Shvarts, D.

    2006-08-01

    Unalloyed uranium (PU) and uranium-0.78 wt% Ti alloy (UT) were studied in VISAR-monitored planar impact experiments with initial sample temperatures ranged from 27circC to 860circC. The recorded waveforms was used for obtaining the stress-strain ? (\\varepsilon ) and deviator stress-strain s(\\varepsilon) diagrams, the conventional elastic limit Y0.2, and the spall strength of the alloys at different testing temperatures. The strengths Y0.2 of both the materials stay almost constant up to the temperature of ? -? transformation, increase strongly in the ?-phase domain, and abruptly drop above the temperature of ? -? transformation. The temperature dependences of the spall strength of alloys differ from those of the compressive strengths indicating the prevailing role of the void nucleation (over the void growth) in the spallation process. The most striking finding of the work is the existence of beta-uranium at pressures some 3 GPa higher than that permitted thermodynamically. The life time and the borders of existence of this non-equilibrium phase are unknown and should be determined in future.

  5. National Uranium Resource Evaluation: Escalante Quadrangle, Utah

    SciTech Connect

    Peterson, F.; Campbell, J.A.; Franczyk, K.J.; Lupe, R.D.

    1982-09-01

    Seven areas favorable for the occurrence of uranium deposits meet the minimum size and grade requirements of the National Uranium Resource Evaluation of the US Department of Energy in the Escalante 1/sup 0/ x 2/sup 0/ Quadrangle, South-Central Utah. Five areas identified in the Late Jurassic Salt Wash Member of the Morrison Formation are: the Henry Mountains mineral belt, and the Bitter Creek, Cat Pasture, Carcass Canyon, and Fiftymile Point areas. The evaluation of these areas was based on the presence of the following features: fluvial sandstones deposited by low-energy streams; actively subsiding synclines; paleostream transport directions approximately perpendicular to the trend of the paleofolds; presence of favorable gray lacustrine mudstone; and known uranium occurrences associated with the favorable gray mudstones. Four favorable areas identified in the Late Triassic Chinle Formation are the White Canyon-Elk Ridge, Dirty Devil-Orange Cliffs, Monument Valley, and the Greater Circle Cliffs subareas. These areas were identified as favorable on the basis of the sandstone-to-shale ratio for the Chinle Formation, and the geographic distribution of the Petrified Forest Member of the Chinle.

  6. Monitoring genotoxic exposure in uranium miners

    SciTech Connect

    Sram, R.J.; Binkova, B.; Dobias, L.; Roessner, P.T.; Topinka, J.; Vesela, D.; Vesely, D.; Stejskalova, J.; Bavorova, H.; Rericha, V. (Institute of Experimental Medicine, Prague (Czechoslovakia))

    1993-03-01

    Recent data from deep uranium mines in Czechoslovakia indicated that in addition to radon daughter products, miners are also exposed to chemical mutagens. Mycotoxins were identified as a possible source of mutagenicity present in the mines. Various methods of biomonitoring were used to examine three groups of miners from different uranium mines. Cytogenetic analysis of peripheral lymphocytes, unscheduled DNA synthesis (UDS) in lymphocytes, and lipid peroxidation (LPO) in both plasma and lymphocytes were studied on 66 exposed miners and 56 controls. Throat swabs were taken from 116 miners and 78 controls. Significantly increased numbers of aberrant cells were found in all groups of miners, as well as decreased UDS values in lymphocytes and increased LPO plasma levels in comparison to controls. Molds were detected in throat swabs from 27% of miners, and 58% of these molds were embryotoxic. Only 5% of the control samples contained molds and none of them was embryotoxic. The following mycotoxins were isolated from miners' throat swab samples: rugulosin, sterigmatocystin, mycophenolic acid, brevianamid A, citreoviridin, citrinin, penicilic acid, and secalonic acid. These data suggest that mycotoxins are a genotoxic factor affecting uranium miners.

  7. X-Ray Emission from "Uranium" Stars

    NASA Technical Reports Server (NTRS)

    Schlegel, Eric; Mushotzky, Richard (Technical Monitor)

    2005-01-01

    The project aims to secure XMM observations of two targets with extremely low abundances of the majority of heavy elements (e.g., log[Fe/H] $\\sim$-4), but that show absorption lines of uranium. The presence of an r-process element such as uranium requires a binary star system in which the companion underwent a supernova explosion. A binary star system raises the distinct possibility of the existence of a compact object, most likely a neutron star, in the binary, assuming it survived the supernova blast. The presence of a compact object then suggests X-ray emission if sufficient matter accretes to the compact object. The observations were completed less than one year ago following a series of reobservations to correct for significant flaring that occurred during the original observations. The ROSAT all-sky survey was used to report on the initial assessment of X-ray emission from these objects; only upper limits were reported. These upper limits were used to justify the XMM observing time, but with the expectation that upper limits would merely be pushed lower. The data analysis hinges critically on the quality and degree of precision with which the background is handled. During the past year, I have spent some time learning the ins and outs of XMM data analysis. In the coming year, I can apply that learning to the analysis of the 'uranium' stars.

  8. 10 CFR 760.1 - Uranium leases on lands controlled by DOE. (Domestic Uranium Program Circular No. 760.1, formerly...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    Uranium leases on lands controlled by DOE. (Domestic Uranium Program Circular No. 760.1, formerly (AEC) Domestic Uranium Program Circular 8, 10 CFR 60.8). 760.1 Section 760.1 Energy DEPARTMENT OF ENERGY DOMESTIC URANIUM PROGRAM §...

  9. 10 CFR 760.1 - Uranium leases on lands controlled by DOE. (Domestic Uranium Program Circular No. 760.1, formerly...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    Uranium leases on lands controlled by DOE. (Domestic Uranium Program Circular No. 760.1, formerly (AEC) Domestic Uranium Program Circular 8, 10 CFR 60.8). 760.1 Section 760.1 Energy DEPARTMENT OF ENERGY DOMESTIC URANIUM PROGRAM §...

  10. 10 CFR 760.1 - Uranium leases on lands controlled by DOE. (Domestic Uranium Program Circular No. 760.1, formerly...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    Uranium leases on lands controlled by DOE. (Domestic Uranium Program Circular No. 760.1, formerly (AEC) Domestic Uranium Program Circular 8, 10 CFR 60.8). 760.1 Section 760.1 Energy DEPARTMENT OF ENERGY DOMESTIC URANIUM PROGRAM §...

  11. 10 CFR 760.1 - Uranium leases on lands controlled by DOE. (Domestic Uranium Program Circular No. 760.1, formerly...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    Uranium leases on lands controlled by DOE. (Domestic Uranium Program Circular No. 760.1, formerly (AEC) Domestic Uranium Program Circular 8, 10 CFR 60.8). 760.1 Section 760.1 Energy DEPARTMENT OF ENERGY DOMESTIC URANIUM PROGRAM §...

  12. Oxidative ammonolysis of uranium(IV) fluorides to uranium(VI) nitride

    NASA Astrophysics Data System (ADS)

    Yeamans, Charles B.; Silva, G. W. Chinthaka; Cerefice, Gary S.; Czerwinski, Kenneth R.; Hartmann, Thomas; Burrell, Anthony K.; Sattelberger, Alfred P.

    2008-02-01

    Actinide nitrides, in particular UN, are being considered as fuel types for advanced reactor systems. Here, we demonstrate a low-temperature synthesis route on uranium that could be developed into a commercial fabrication process for UN and mixed actinide nitride fuels. UN was successfully synthesized from UO 2 by first reacting with NH 4HF 2 in a ball mill at 20 °C to form tetravalent ammonium uranium fluorides. Then, reaction with an ammonia atmosphere at 800 °C oxidized tetravalent uranium fluorides to hexavalent UN 2. The final product, UN, was obtained by decomposing UN 2 at 1100 °C under argon to produce UN through an intermediate phase of U 2N 3.

  13. Uranium from Seawater Program Review; Fuel Resources Uranium from Seawater Program DOE Office of Nuclear Energy

    SciTech Connect

    none,

    2013-07-01

    For nuclear energy to remain sustainable in the United States, economically viable sources of uranium beyond terrestrial ores must be developed. The goal of this program is to develop advanced adsorbents that can extract uranium from seawater at twice the capacity of the best adsorbent developed by researchers at the Japan Atomic Energy Agency (JAEA), 1.5 mg U/g adsorbent. A multidisciplinary team from Oak Ridge National Laboratory, Lawrence Berkeley National Laboratory, Pacific Northwest National Laboratory, and the University of Texas at Austin was assembled to address this challenging problem. Polymeric adsorbents, based on the radiation grafting of acrylonitrile and methacrylic acid onto high surface-area polyethylene fibers followed by conversion of the nitriles to amidoximes, have been developed. These poly(acrylamidoxime-co-methacrylic acid) fibers showed uranium adsorption capacities for the extraction of uranium from seawater that exceed 3 mg U/g adsorbent in testing at the Pacific Northwest National Laboratory Marine Sciences Laboratory. The essence of this novel technology lies in the unique high surface-area trunk material that considerably increases the grafting yield of functional groups without compromising its mechanical properties. This technology received an R&D100 Award in 2012. In addition, high surface area nanomaterial adsorbents are under development with the goal of increasing uranium adsorption capacity by taking advantage of the high surface areas and tunable porosity of carbon-based nanomaterials. Simultaneously, de novo structure-based computational design methods are being used to design more selective and stable ligands and the most promising candidates are being synthesized, tested and evaluated for incorporation onto a support matrix. Fundamental thermodynamic and kinetic studies are being carried out to improve the adsorption efficiency, the selectivity of uranium over other metals, and the stability of the adsorbents. Understanding the rate-limiting step of uranium uptake from seawater is also essential in designing an effective uranium recovery system. Finally, economic analyses have been used to guide these studies and highlight what parameters, such as capacity, recyclability, and stability, have the largest impact on the cost of extraction of uranium from seawater. Initially, the cost estimates by the JAEA for extraction of uranium from seawater with braided polymeric fibers functionalized with amidoxime ligands were evaluated and updated. The economic analyses were subsequently updated to reflect the results of this project while providing insight for cost reductions in the adsorbent development through “cradle-to-grave” case studies for the extraction process. This report highlights the progress made over the last three years on the design, synthesis, and testing of new materials to extract uranium for seawater. This report is organized into sections that highlight the major research activities in this project: (1) Chelate Design and Modeling, (2) Thermodynamics, Kinetics and Structure, (3) Advanced Polymeric Adsorbents by Radiation Induced Grafting, (4) Advanced Nanomaterial Adsorbents, (5) Adsorbent Screening and Modeling, (6) Marine Testing, and (7) Cost and Energy Assessment. At the end of each section, future research directions are briefly discussed to highlight the challenges that still remain to reduce the cost of extractions of uranium for seawater. Finally, contributions from the Nuclear Energy University Programs (NEUP), which complement this research program, are included at the end of this report.

  14. Basic characterization of highly enriched uranium by gamma spectrometry

    E-print Network

    Cong Tam Nguyen; Jozsef Zsigrai

    2005-08-25

    Gamma-spectrometric methods suitable for the characterization of highly enriched uranium samples encountered in illicit trafficking of nuclear materials are presented. In particular, procedures for determining the 234U, 235U, 238U, 232U and 236U contents and the age of highly enriched uranium are described. Consequently, the total uranium content and isotopic composition can be calculated. For determining the 238U and 232U contents a low background chamber was used. In addition, age dating of uranium was also performed using low-background spectrometry.

  15. Uranium quantification in semen by inductively coupled plasma mass spectrometry.

    PubMed

    Todorov, Todor I; Ejnik, John W; Guandalini, Gustavo; Xu, Hanna; Hoover, Dennis; Anderson, Larry; Squibb, Katherine; McDiarmid, Melissa A; Centeno, Jose A

    2013-01-01

    In this study we report uranium analysis for human semen samples. Uranium quantification was performed by inductively coupled plasma mass spectrometry. No additives, such as chymotrypsin or bovine serum albumin, were used for semen liquefaction, as they showed significant uranium content. For method validation we spiked 2g aliquots of pooled control semen at three different levels of uranium: low at 5 pg/g, medium at 50 pg/g, and high at 1000 pg/g. The detection limit was determined to be 0.8 pg/g uranium in human semen. The data reproduced within 1.4-7% RSD and spike recoveries were 97-100%. The uranium level of the unspiked, pooled control semen was 2.9 pg/g of semen (n=10). In addition six semen samples from a cohort of Veterans exposed to depleted uranium (DU) in the 1991 Gulf War were analyzed with no knowledge of their exposure history. Uranium levels in the Veterans' semen samples ranged from undetectable (<0.8 pg/g) to 3350 pg/g. This wide concentration range for uranium in semen is consistent with known differences in current DU body burdens in these individuals, some of whom have retained embedded DU fragments. PMID:22944582

  16. Plant-uptake of uranium: Hydroponic and soil system studies

    USGS Publications Warehouse

    Ramaswami, A.; Carr, P.; Burkhardt, M.

    2001-01-01

    Limited information is available on screening and selection of terrestrial plants for uptake and translocation of uranium from soil. This article evaluates the removal of uranium from water and soil by selected plants, comparing plant performance in hydroponic systems with that in two soil systems (a sandy-loam soil and an organic-rich soil). Plants selected for this study were Sunflower (Helianthus giganteus), Spring Vetch (Vicia sativa), Hairy Vetch (Vicia villosa), Juniper (Juniperus monosperma), Indian Mustard (Brassica juncea), and Bush Bean (Phaseolus nanus). Plant performance was evaluated both in terms of the percent uranium extracted from the three systems, as well as the biological absorption coefficient (BAC) that normalized uranium uptake to plant biomass. Study results indicate that uranium extraction efficiency decreased sharply across hydroponic, sandy and organic soil systems, indicating that soil organic matter sequestered uranium, rendering it largely unavailable for plant uptake. These results indicate that site-specific soils must be used to screen plants for uranium extraction capability; plant behavior in hydroponic systems does not correlate well with that in soil systems. One plant species, Juniper, exhibited consistent uranium extraction efficiencies and BACs in both sandy and organic soils, suggesting unique uranium extraction capabilities.

  17. Challenges dealing with depleted uranium in Germany - Reuse or disposal

    SciTech Connect

    Moeller, Kai D. [Federal Office for Radiation Protection, Bundesamt fuer Strahlenschutz - BFS, Postfach 10 01 49, D-38201 Salzgitter (Germany)

    2007-07-01

    During enrichment large amounts of depleted Uranium are produced. In Germany every year 2.800 tons of depleted uranium are generated. In Germany depleted uranium is not classified as radioactive waste but a resource for further enrichment. Therefore since 1996 depleted Uranium is sent to ROSATOM in Russia. However it still has to be dealt with the second generation of depleted Uranium. To evaluate the alternative actions in case a solution has to be found in Germany, several studies have been initiated by the Federal Ministry of the Environment. The work that has been carried out evaluated various possibilities to deal with depleted uranium. The international studies on this field and the situation in Germany have been analyzed. In case no further enrichment is planned the depleted uranium has to be stored. In the enrichment process UF{sub 6} is generated. It is an international consensus that for storage it should be converted to U{sub 3}O{sub 8}. The necessary technique is well established. If the depleted Uranium would have to be characterized as radioactive waste, a final disposal would become necessary. For the planned Konrad repository - a repository for non heat generating radioactive waste - the amount of Uranium is limited by the licensing authority. The existing license would not allow the final disposal of large amounts of depleted Uranium in the Konrad repository. The potential effect on the safety case has not been roughly analyzed. As a result it may be necessary to think about alternatives. Several possibilities for the use of depleted uranium in the industry have been identified. Studies indicate that the properties of Uranium would make it useful in some industrial fields. Nevertheless many practical and legal questions are open. One further option may be the use as shielding e.g. in casks for transport or disposal. Possible techniques for using depleted Uranium as shielding are the use of the metallic Uranium as well as the inclusion in concrete. Another possibility could be the use of depleted uranium for the blending of High enriched Uranium (HEU) or with Plutonium to MOX-elements. (authors)

  18. Uranium transport in the Walker River Basin, California and Nevada

    USGS Publications Warehouse

    Benson, L.V.; Leach, D.L.

    1979-01-01

    During the summer of 1976 waters from tributaries, rivers, springs and wells were sampled in the Walker River Basin. Snow and sediments from selected sites were also sampled. All samples were analyzed for uranium and other elements. The resulting data provide an understanding of the transport of uranium within a closed hydrologic basin as well as providing a basis for the design of geochemical reconnaissance studies for the Basin and Range Province of the Western United States. Spring and tributary data are useful in locating areas containing anomalous concentrations of uranium. However, agricultural practices obscure the presence of known uranium deposits and render impossible the detection of other known deposits. Uranium is extremely mobile in stream waters and does not appear to sorb or precipitate. Uranium has a long residence time (2500 years) in the open waters of Walker Lake; however, once it crosses the sediment-water interface, it is reduced to the U(IV) state and is lost from solution. Over the past two million years the amount of uranium transported to the terminal point of the Walker River system may have been on the order of 4 ?? 108 kg. This suggests that closed basin termini are sites for significant uranium accumulations and are, therefore, potential sites of uranium ore deposits. ?? 1979.

  19. Measurements of uranium in soils and small mammals

    SciTech Connect

    Miera, F.R. Jr.

    1980-12-01

    The objective of this study was to evaluate the bioavailability of uranium to a single species of small mammal, Peromyscus maniculatus rufinus (Merriam), white-footed deer mouse, from two different source terms: a Los Alamos National Laboratory dynamic weapons testing site in north central New Mexico, where an estimated 70,000 kg of uranium have been expended over a 31-y period; and an inactive uranium mill tailings pile located in west central New Mexico near Grants, which received wastes over a 5-y period from the milling of 2.7 x 10/sup 9/ kg of uranium ore.

  20. Partially ionized plasmas, including the Third Symposium on Uranium Plasmas

    NASA Technical Reports Server (NTRS)

    Krishnan, M.

    1976-01-01

    Fundamentals of both electrically and fission generated plasmas are discussed. Research in gaseous fuel reactors using uranium hexafluoride is described and other partially ionized plasma applications are discussed.

  1. Degradation problems with the solvent extraction organic at Roessing uranium

    SciTech Connect

    Munyungano, Brodrick [Roessing Uranium Ltd, Private Bag 5005, Swakopmund (Namibia); Feather, Angus [Cognis, P. O. Box 361, Honeydew, 2040 (South Africa); Virnig, Michael [Cognis Corporation, 2430 N. Huachuca Dr, Tucson, Az (United States)

    2008-07-01

    Roessing Uranium Ltd recovers uranium from a low-grade ore in Namibia. Uranium is recovered and purified from an ion-exchange eluate in a solvent-extraction plant. The solvent-extraction plant uses Alamine 336 as the extractant for uranium, with isodecanol used as a phase modifier in Sasol SSX 210, an aliphatic hydrocarbon diluent. Since the plant started in the mid 1970's, there have been a few episodes where the tertiary amine has been quickly and severely degraded when the plant was operated outside certain operating parameters. The Rossing experience is discussed in more detail in this paper. (authors)

  2. Method of fabricating a uranium-bearing foil

    DOEpatents

    Gooch, Jackie G. (Seymour, TN); DeMint, Amy L. (Kingston, TN)

    2012-04-24

    Methods of fabricating a uranium-bearing foil are described. The foil may be substantially pure uranium, or may be a uranium alloy such as a uranium-molybdenum alloy. The method typically includes a series of hot rolling operations on a cast plate material to form a thin sheet. These hot rolling operations are typically performed using a process where each pass reduces the thickness of the plate by a substantially constant percentage. The sheet is typically then annealed and then cooled. The process typically concludes with a series of cold rolling passes where each pass reduces the thickness of the plate by a substantially constant thickness amount to form the foil.

  3. Fissioning uranium plasmas and nuclear-pumped lasers

    NASA Technical Reports Server (NTRS)

    Schneider, R. T.; Thom, K.

    1975-01-01

    Current research into uranium plasmas, gaseous-core (cavity) reactors, and nuclear-pumped lasers is discussed. Basic properties of fissioning uranium plasmas are summarized together with potential space and terrestrial applications of gaseous-core reactors and nuclear-pumped lasers. Conditions for criticality of a uranium plasma are outlined, and it is shown that the nonequilibrium state and the optical thinness of a fissioning plasma can be exploited for the direct conversion of fission fragment energy into coherent light (i.e., for nuclear-pumped lasers). Successful demonstrations of nuclear-pumped lasers are described together with gaseous-fuel reactor experiments using uranium hexafluoride.

  4. Selective leaching of uranium from uranium-contaminated soils: Progress report 1

    SciTech Connect

    Francis, C.W.; Mattus, A.J.; Farr, L.L.; Elless, M.P.; Lee, S.Y.

    1993-02-01

    Three soils and a sediment contaminated with uranium were used to determine the effectiveness of sodium carbonate and citric acid leaching to decontaminated or remove uranium to acceptable regulatory levels. Two of the soils were surface soils from the DOE facility formerly called the Feed Materials Production Center (FMPC) at Fernald, Ohio. This facility is presently called the Femald Environmental Management Project (FEMP). Carbonate extractions generally removed from 70 to 90% of the uranium from the Fernald storage pad soil. Uranium was slightly more difficult to extract from the Fernald incinerator and the Y-12 landfarm soils. Very small amounts of uranium could be extracted from the storm sewer sediment. Extraction with carbonate at high solution-to-soil ratios were as effective as extractions at low solution-to-soil ratios, indicating attrition by the paddle mixer was not significantly different than that provided in a rotary extractor. Also, pretreatments such as milling or pulverizing the soil sample did not appear to increase extraction efficiency when carbonate extractions were carried out at elevated temperatures (60[degree]C) or long extraction times (23 h). Adding KMnO[sub 4] in the carbonate extraction appeared to increase extraction efficiency from the Fernald incinerator soil but not the Fernald storage pad soil. The most effective leaching rates (> 90 % from both Fernald soils) were obtained using a citrate/dithionite extraction procedure designed to remove amorphous (noncrystalline) iron/aluminum sesquioxides from surfaces of clay minerals. Citric acid also proved to be a very good extractant for uranium.

  5. Selective leaching of uranium from uranium-contaminated soils: Progress report 1

    SciTech Connect

    Francis, C.W.; Mattus, A.J.; Farr, L.L.; Elless, M.P.; Lee, S.Y.

    1993-02-01

    Three soils and a sediment contaminated with uranium were used to determine the effectiveness of sodium carbonate and citric acid leaching to decontaminated or remove uranium to acceptable regulatory levels. Two of the soils were surface soils from the DOE facility formerly called the Feed Materials Production Center (FMPC) at Fernald, Ohio. This facility is presently called the Femald Environmental Management Project (FEMP). Carbonate extractions generally removed from 70 to 90% of the uranium from the Fernald storage pad soil. Uranium was slightly more difficult to extract from the Fernald incinerator and the Y-12 landfarm soils. Very small amounts of uranium could be extracted from the storm sewer sediment. Extraction with carbonate at high solution-to-soil ratios were as effective as extractions at low solution-to-soil ratios, indicating attrition by the paddle mixer was not significantly different than that provided in a rotary extractor. Also, pretreatments such as milling or pulverizing the soil sample did not appear to increase extraction efficiency when carbonate extractions were carried out at elevated temperatures (60{degree}C) or long extraction times (23 h). Adding KMnO{sub 4} in the carbonate extraction appeared to increase extraction efficiency from the Fernald incinerator soil but not the Fernald storage pad soil. The most effective leaching rates (> 90 % from both Fernald soils) were obtained using a citrate/dithionite extraction procedure designed to remove amorphous (noncrystalline) iron/aluminum sesquioxides from surfaces of clay minerals. Citric acid also proved to be a very good extractant for uranium.

  6. A review of the effects of uranium and depleted uranium exposure on reproduction and fetal development.

    PubMed

    Arfsten, D P; Still, K R; Ritchie, G D

    2001-06-01

    Depleted uranium (DU) is used in armor-penetrating munitions, military vehicle armor, and aircraft, ship and missile counterweighting/ballasting, as well as in a number of other military and commercial applications. Recent combat applications of DU alloy [i.e., Persian Gulf War (PGW) and Kosovo peacekeeping objective] resulted in human acute exposure to DU dust, vapor or aerosol, as well as chronic exposure from tissue embedding of DU shrapnel fragments. DU alloy is 99.8% 238Uranium, and emits approximately 60% of the alpha, beta, and gamma radiation found in natural uranium (4.05 x 10(-7) Ci/g DU alloy). DU is a heavy metal that is 160% more dense than lead and can remain within the body for many years and slowly solubilize. High levels of urinary uranium have been measured in PGW veterans 10 years after exposure to DU fragments and vapors. In rats, there is strong evidence of DU accumulation in tissues including testes, bone, kidneys, and brain. In vitro tests indicate that DU alloy may be both genotoxic and mutagenic, whereas a recent in vivo study suggests that tissue-embedded DU alloy may be carcinogenic in rats. There is limited available data for reproductive and teratological deficits from exposure to uranium per se, typically from oral, respiratory, or dermal exposure routes. Alternatively, there is no data available on the reproductive effects of DU embedded. This paper reviews published studies of reproductive toxicity in humans and animals from uranium or DU exposure, and discusses ongoing animal research to evaluate reproductive effects in male and female rats embedded with DU fragments, and possible consequences in F1 and F2 generations. PMID:12539863

  7. Examination of long-stored uranium metal

    SciTech Connect

    Gate, A.M.; Hambley, D.I. [National Nuclear Laboratory, Sellafield, Seascale, Cumbria, CA20 1PG (United Kingdom)

    2013-07-01

    A small quantity of unirradiated uranium from Magnox fuel elements is currently held in archive storage. Some of these samples date back to the late fifties. This material has been stored, untreated, in unsealed containers in air at ambient temperature, humidity and pressure conditions. Such conditions are relevant to those that may exist in a passive storage facility. A sample of this material has been subject to optical, electron-optical and Raman spectroscopic examination to determine the extent of corrosion and the composition of corrosion product arising from long-term, low-temperature oxidation of uranium metal in air. The examinations have established that, even after a period in excess of 40 years, there was no observable spalling of uranium oxide from the sample during storage. The extent of oxidation of the metal, derived by SEM analysis, was slight and insignificant in relation to overall structural stability of the material. Raman spectroscopy data showed that the bulk of the oxide layer was comprised of hyper-stoichiometric UO{sub 2}, with U{sub 4}O{sub 9} being the dominant component. The oxygen/uranium ratio was observed to be decreased at the metal/oxide interface, with a very thin layer that consisted of mainly UO{sub 2} at the metal surface. At the oxide/air interface, a very thin U{sub 3}O{sub 8} layer was detected. U{sub 4}O{sub 9} is relatively mechanically stable, due to a significantly higher density than UO{sub 2} and U{sub 3}O{sub 8}. It is likely that the lower internal stresses in the thick U{sub 4}O{sub 9} layer have resulted in less oxide film cracking than would be expected from UO{sub 2} or U{sub 3}O{sub 8} and hence the low oxidation rate observed. These results suggest that storage of uranium metal in air over decades is a safe and credible option. (authors)

  8. Evaluation and application of anion exchange resins to measure groundwater uranium flux at a former uranium mill site.

    PubMed

    Stucker, Valerie; Ranville, James; Newman, Mark; Peacock, Aaron; Cho, Jaehyun; Hatfield, Kirk

    2011-10-15

    Laboratory tests and a field validation experiment were performed to evaluate anion exchange resins for uranium sorption and desorption in order to develop a uranium passive flux meter (PFM). The mass of uranium sorbed to the resin and corresponding masses of alcohol tracers eluted over the duration of groundwater installation are then used to determine the groundwater and uranium contaminant fluxes. Laboratory based batch experiments were performed using Purolite A500, Dowex 21K and 21K XLT, Lewatit S6328 A resins and silver impregnated activated carbon to examine uranium sorption and extraction for each material. The Dowex resins had the highest uranium sorption, followed by Lewatit, Purolite and the activated carbon. Recoveries from all ion exchange resins were in the range of 94-99% for aqueous uranium in the environmentally relevant concentration range studied (0.01-200 ppb). Due to the lower price and well-characterized tracer capacity, Lewatit S6328 A was used for field-testing of PFMs at the DOE UMTRA site in Rifle, CO. The effect on the flux measurements of extractant (nitric acid)/resin ratio, and uranium loading were investigated. Higher cumulative uranium fluxes (as seen with concentrations>1 ug U/gram resin) yielded more homogeneous resin samples versus lower cumulative fluxes (<1 ug U/gram resin), which caused the PFM to have areas of localized concentration of uranium. Resin homogenization and larger volume extractions yield reproducible results for all levels of uranium fluxes. Although PFM design can be improved to measure flux and groundwater flow direction, the current methodology can be applied to uranium transport studies. PMID:21798572

  9. Lichens as biomonitors of uranium and other trace elements in an area of Kosovo heavily shelled with depleted uranium rounds

    Microsoft Academic Search

    Luigi A. Di Lella; Luisa Frati; Stefano Loppi; Giuseppe Protano; Francesco Riccobono

    2003-01-01

    This paper reports the results of a study using lichens as biomonitors to investigate the small-scale environmental distribution of uranium and other trace elements in an area of Kosovo (Djakovica) heavily shelled with depleted uranium (DU) anti-tank ammunition. The results of total uranium concentrations showed great variability and species-specific differences, mainly due to differences in the exposed surface area of

  10. Evolution of uranium and thorium minerals

    NASA Astrophysics Data System (ADS)

    Hazen, R. M.; Ewing, R. C.; Sverjensky, D. A.

    2009-12-01

    The origins and near-surface distributions of the approximately 250 known uranium and/or thorium minerals elucidate principles of mineral evolution. This history can be divided into four phases. The first, from ~4.5 to 3.5 Ga, involved successive concentrations of uranium and thorium from their initial uniform trace distribution into magmatic-related fluids from which the first U4+ and Th4+ minerals, uraninite (UO2), thorianite (ThO2) and coffinite (USiO4), precipitated in the crust. The second period, from ~3.5 to 2.2 Ga, saw the formation of large low-grade concentrations of detrital uraninite (containing several weight percent Th) in the Witwatersrand-type quartz-pebble conglomerates deposited in a highly anoxic fluvial environment. Abiotic alteration of uraninite and coffinite, including radiolysis and auto-oxidation caused by radioactive decay and the formation of helium from alpha particles, may have resulted in the formation of a limited suite of uranyl oxide-hydroxides. Earth’s third phase of uranium mineral evolution, during which most known U minerals first precipitated from reactions of soluble uranyl (U6+O2)2+ complexes, followed the Great Oxidation Event (GOE) at ~2.2 Ga and thus was mediated indirectly by biologic activity. Most uraninite deposited during this phase was low in Th and precipitated from saline and oxidizing hydrothermal solutions (100 to 300°C) transporting (UO2)2+-chloride complexes. Examples include the unconformity- and vein-type U deposits (Australia and Canada) and the unique Oklo natural nuclear reactors in Gabon. The onset of hydrothermal transport of (UO2)2+ complexes in the upper crust may reflect the availability of CaSO4-bearing evaporites after the GOE. During this phase, most uranyl minerals would have been able to form in the O2-bearing near-surface environment for the first time through weathering processes. The fourth phase of uranium mineralization began approximately 400 million years ago, as the rise of land plants led to non-marine organic-rich sediments that promoted new sandstone-type ore deposits. The modes of accumulation and even the compositions of uraninite, as well as the multiple oxidation states of U (4+, 5+, and 6+), are a sensitive indicator of global redox conditions. In contrast, the behavior of thorium, which has only a single oxidation state (4+) that has a very low solubility in the absence of aqueous F-complexes, cannot reflect changing redox conditions. Geochemical concentration of Th relative to U at high temperatures is therefore limited to special magmatic-related environments, where U4+ is preferentially removed by chloride or carbonate complexes, and at low temperatures by mineral surface reactions. The near-surface mineralogy of uranium and thorium provide a measure of a planet’s geotectonic and geobiological history. In the absence of extensive magmatic-related fluid reworking of the crust and upper mantle, uranium and thorium will not become sufficiently concentrated to form their own minerals or ore deposits. Furthermore, in the absence of surface oxidation, all but a handful of the known uranium minerals are unlikely to form.

  11. Cost estimate report for the long-term management of depleted uranium hexafluoride : storage of depleted uranium metal.

    SciTech Connect

    Folga, S.M.; Kier, P.H.; Thimmapuram, P.R.

    2001-01-24

    This report contains a cost analysis of the long-term storage of depleted uranium in the form of uranium metal. Three options are considered for storage of the depleted uranium. These options are aboveground buildings, partly underground vaults, and mined cavities. Three cases are presented. In the first case, all the depleted uranium metal that would be produced from the conversion of depleted uranium hexafluoride (UF{sub 6}) generated by the US Department of Energy (DOE) prior to July 1993 would be stored at the storage facility (100% Case). In the second case, half the depleted uranium metal would be stored at this storage facility (50% Case). In the third case, one-quarter of the depleted uranium metal would be stored at the storage facility (25% Case). The technical basis for the cost analysis presented in this report is principally found in the companion report, ANL/EAD/TM-100, ''Engineering Analysis Report for the Long-Term Management of Depleted Uranium Hexafluoride: Storage of Depleted Uranium Metal'', prepared by Argonne National Laboratory.

  12. Process for recovering uranium from waste hydrocarbon oils containing the same. [Uranium contaminated lubricating oils from gaseous diffusion compressors

    DOEpatents

    Conrad, M.C.; Getz, P.A.; Hickman, J.E.; Payne, L.D.

    1982-06-29

    The invention is a process for the recovery of uranium from uranium-bearing hydrocarbon oils containing carboxylic acid as a degradation product. In one aspect, the invention comprises providing an emulsion of water and the oil, heating the same to a temperature effecting conversion of the emulsion to an organic phase and to an acidic aqueous phase containing uranium carboxylate, and recovering the uranium from the aqueous phase. The process is effective, simple and comparatively inexpensive. It avoids the use of toxic reagents and the formation of undesirable intermediates.

  13. DOE's Stewardship of Government-Owned Uranium Materials

    SciTech Connect

    Jackson, J. Dale [U.S. Department of Energy, 1000 Independence Ave., SW Washington, DC 20585 (United States); Donaldson, Dale E. [AIMS Inc. (United States)

    2002-07-01

    Beginning in the 1980's, a significant number of Department of Energy facilities have been shut down and are in the decommissioning process. The shutdown of additional facilities is planned. In addition, during the past several decades, the Department of Energy has loaned nuclear material to a wide variety of private and governmental institutions for research and educational purposes. Subsequent changes in the Department's priorities have reduced the need for nuclear materials to support the Department's programs. Similarly, there has been a reduction in the need for borrowed nuclear materials by organizations and institutions using nuclear materials 'on loan' from the Department. As a result, inventories of uranium material from the Department's facilities and 'on loan' must be removed and returned to the Department. This material is in the form of low enriched uranium (LEU), normal uranium (NU), and depleted uranium (DU) in various forms. This uranium material is located at over one hundred sites within the United States and overseas, including universities and laboratories. Much of this uranium is not needed to support national priorities and programs. The Department of Energy has assumed a stewardship role in managing nuclear materials throughout their life cycle, from acquisition to storage. Surplus uranium has created challenges for DOE in managing and storing the material as well as identifying opportunities for its further use. On behalf of the Department, the Oak Ridge Operations Office has been given the responsibility to implement the Department responsibilities in meeting these challenges and managing the Department's uranium materials. To support this effort, the Office of Nuclear Fuel Security and Uranium Technology within the ORO complex coordinates uranium management functions across the Department of Energy. This coordination provides DOE with a number of important benefits, among which are: consolidated management and storage of uranium; improved security; a reduction of operating costs; effective use and reuse of DOT certified shipping containers; and accelerated site closure. (authors)

  14. Uranium isotopes in ground water as a prospecting technique

    SciTech Connect

    Cowart, J.B.; Osmond, J.K.

    1980-02-01

    The isotopic concentrations of dissolved uranium were determined for 300 ground water samples near eight known uranium accumulations to see if new approaches to prospecting could be developed. It is concluded that a plot of /sup 234/U//sup 238/U activity ratio (A.R.) versus uranium concentration (C) can be used to identify redox fronts, to locate uranium accumulations, and to determine whether such accumulations are being augmented or depleted by contemporary aquifer/ground water conditions. In aquifers exhibiting flow-through hydrologic systems, up-dip ground water samples are characterized by high uranium concentration values (> 1 to 4 ppB) and down-dip samples by low uranium concentration values (less than 1 ppB). The boundary between these two regimes can usually be identified as a redox front on the basis of regional water chemistry and known uranium accumulations. Close proximity to uranium accumulations is usually indicated either by very high uranium concentrations in the ground water or by a combination of high concentration and high activity ratio values. Ground waters down-dip from such accumulations often exhibit low uranium concentration values but retain their high A.R. values. This serves as a regional indicator of possible uranium accumulations where conditions favor the continued augmentation of the deposit by precipitation from ground water. Where the accumulation is being dispersed and depleted by the ground water system, low A.R. values are observed. Results from the Gulf Coast District of Texas and the Wyoming districts are presented.

  15. Understanding aerosols in uranium mines in order to compute the lung dose for uranium miners

    Microsoft Academic Search

    Alfred J. Cavallo

    1997-01-01

    The radon risk coefficient is determined from long term epidemiology studies of lung cancer incidence among uranium miners. The current estimate of 350 lung cancer deaths per million person Working Level Month was proposed by the Committee on the Biological Effects of Ionizing Radiation (BEIR IV, 1988), based on these studies.The unit of working level month is a measure of

  16. Phytoremediation of uranium-contaminated soils: Role of organic acids in triggering uranium hyperaccumulation in plants

    Microsoft Academic Search

    Jianwei W. Huang; Michael J. Blaylock; Yoram Kapulnik; Burt D. Ensley

    1998-01-01

    Uranium phytoextraction, the use of plants to extract U from contaminated soils, is an emerging technology. The authors report on the development of this technology for the cleanup of U-contaminated soils. In this research, they investigated the effects of various soil amendments on U desorption from soil to soil solution, studied the physiological characteristics of U uptake and accumulation in

  17. Environmental Problems Relating to Uranium Mining and Milling

    Microsoft Academic Search

    FRANK B. FRIEDMAN

    1978-01-01

    The author outlines some legal and jurisdictional complexities associated with changes in the uranium market as demand growth and environmental policy changes affect the environmental impacts of mining and milling. He describes the interrelated jurisdictions within the Nuclear Regulatory Commission, state legislatures, and the Environmental Protection Agency. In situ uranium leach mining will be affected by the Safe Drinking Water

  18. URANIUM ORES AND THE ENVIRONMENTAL IMPACT ON HUMAN HEALTH RISKS

    Microsoft Academic Search

    Hanaa Mahmoud Salem

    This paper analyses the importance of the potential human health risks related to radionuclides and metals released from uranium mining and milling activities as well as the health effects of depleted uranium in the environment. Breathing or ingestion of abnormal levels of the radioactive gas radon, derived from natural sources such as rocks, has been considered as carcinogenic and kidney-related

  19. Environmental hydrogeology of in situ leach uranium mining in Australia

    Microsoft Academic Search

    Gavin M. Mudd

    The use of the 'in situ leach' technique of uranium mining is a new de- velopment in Australia's expanding uranium industry. To date there have been three sites of pilot leach mines at Beverley (1998) and Honeymoon (1982, 1998- 2000) in South Australia and at Manyingee (1985) in Western Australia. The Bev- erley and Honeymoon projects gained regulatory approvals in

  20. Acid In Situ Leach Uranium Mining : 1 - USA and Australia

    Microsoft Academic Search

    Gavin M. Mudd

    The technique of In Situ Leach (ISL) uranium mining is well established in the USA, as well as being used extensively in Eastern Europe and the former Soviet Union. The method is being proposed and tested on uranium deposits in Australia, with sulphuric acid chemistry and no restoration of groundwater following mining. The history and problems of acid ISL sites

  1. Radiation impact assessment on wildlife from an uranium mine area

    Microsoft Academic Search

    Marko ?erne; Borut Smodiš; Marko Štrok; Ljudimila Benedik

    Uranium mining and milling activities are one of the major causes of radioactive contamination of the environment. Radionuclides, especially uranium decay-chain products, are released from plant wastes into the soil and water and consequently into vegetation where they may accumulate. Transfer of radionuclides thus represents a radiological risk to humans and non-human organisms due to accumulation of radionuclides in target

  2. Depleted uranium: properties, military use and health risks

    Microsoft Academic Search

    Ian Fairlie

    2009-01-01

    This article describes uranium and depleted uranium (DU), their similar isotopic compositions, how DU arises, its use in munitions and armour-proofing, and its pathways for human exposures. Particular attention is paid to the evidence of DU's health effects from cell and animal experiments and from epidemiology studies. It is concluded that a precautionary approach should be adopted to DU and

  3. Electron Microbeam Investigation of Uranium-Contaminated Soils from

    E-print Network

    Zhu, Chen

    Research Electron Microbeam Investigation of Uranium-Contaminated Soils from Oak Ridge, TN, USA J O Street, Bloomington, Indiana 47405 Two samples of uranium-contaminated soil from the Department of Energy and transmission electron microscopy. The objectives of this research were to identify and characterize soil

  4. Uranium and cesium diffusion in fuel cladding of electrogenerating channel

    SciTech Connect

    Vasil’ev, I. V., E-mail: fnti@mail.ru; Ivanov, A. S.; Churin, V. A. [National Research Center Kurchatov Institute (Russian Federation)

    2014-12-15

    The results of reactor tests of a carbonitride fuel in a single-crystal cladding from a molybdenum-based alloy can be used in substantiating the operational reliability of fuels in developing a project of a megawatt space nuclear power plant. The results of experimental studies of uranium and cesium penetration into the single-crystal cladding of fuel elements with a carbonitride fuel are interpreted. Those fuel elements passed nuclear power tests in the Ya-82 pilot plant for 8300 h at a temperature of about 1500°C. It is shown that the diffusion coefficients for uranium diffusion into the cladding are virtually coincident with the diffusion coefficients measured earlier for uranium diffusion into polycrystalline molybdenum. It is found that the penetration of uranium into the cladding is likely to occur only in the case of a direct contact between the cladding and fuel. The experimentally observed nonmonotonic uranium-concentration profiles are explained in terms of predominant uranium diffusion along grain boundaries. It is shown that a substantially nonmonotonic behavior observed in our experiment for the uranium-concentration profile may be explained by the presence of a polycrystalline structure of the cladding in the surface region from its inner side. The diffusion coefficient is estimated for the grain-boundary diffusion of uranium. The diffusion coefficients for cesium are estimated on the basis of experimental data obtained in the present study.

  5. Process for recovering niobium from uranium-niobium alloys

    DOEpatents

    Wallace, Steven A. (Knoxville, TN); Creech, Edward T. (Oak Ridge, TN); Northcutt, Walter G. (Oak Ridge, TN)

    1983-01-01

    Niobium is recovered from scrap uranium-niobium alloy by melting the scrap with tin, solidifying the billet thus formed, heating the billet to combine niobium with tin therein, placing the billet in hydrochloric acid to dissolve the uranium and leave an insoluble residue of niobium stannide, then separating the niobium stannide from the acid.

  6. Process for recovering niobium from uranium-niobium alloys

    DOEpatents

    Wallace, S.A.; Creech, E.T.; Northcutt, W.G.

    1982-09-27

    Niobium is recovered from scrap uranium-niobium alloy by melting the scrap with tin, solidifying the billet thus formed, heating the billet to combine niobium with tin therein, placing the billet in hydrochloric acid to dissolve the uranium and form a precipitate of niobium stannide, then separating the precipitate from the acid.

  7. DETERMINATION OF RARE EARTH ELEMENTS IN URANIUM COMPOUNDS

    Microsoft Academic Search

    T. Nakazima; M. Takahashi; H. Kawaguchi

    1958-01-01

    A method has been developed for the determination of rare earth elements ; including yttrium in uranium and its compounds. The greater portion of the ; uranium is separated from the rare earths by ether extraction. The rare earths ; are then precipitated as fluorides and subsequently purified as hydroxides. ; Lanthanum was used as the carrier. The efficiency of

  8. Acute toxicity of uranium hexafluoride, uranyl fluoride and hydrogen fluoride

    Microsoft Academic Search

    Just

    1988-01-01

    Uranium hexafluoride (UFâ) released into the atmosphere will react rapidly with moisture in the air to form the hydrolysis products uranyl fluoride (UOâFâ) and hydrogen fluoride (HF). Uranium compounds such as UFâ and UOâFâ exhibit both chemical toxicity and radiological effects, while HF exhibits only chemical toxicity. This paper describes the development of a methodology for assessing the human health

  9. Removal of uranium from aqueous HF solutions. [DOE patent application

    Microsoft Academic Search

    H. Pulley; S. F. Seltzer

    1978-01-01

    This invention is a simple and effective method for removing uranium from aqueous HF solutions containing trace quantities of the same. The method comprises contacting the solution with particulate calcium fluoride to form uranium-bearing particulates, permitting the particulates to settle, and separating the solution from the settled particulates. The CaFâ is selected to have a nitrogen surface area in a

  10. A RAPID PROCEDURE FOR THE SPECTROPHOTOMETRIC DETERMINATION OF URANIUM

    Microsoft Academic Search

    Vogliotti

    1960-01-01

    A rapid method for uranium determination is described. Minerals are ; decomposed by fuming with HF, HNOâ, and HâSOâ. Uranium is then ; extracted by TBP as thiocyanate complex. Part of the interfering ions are first ; masked by EDTA, the extracted ones are washed out from TBP by a proposed solution ; containing KSCN, CHâCOOH, CHâCOONa, EDTA and thioglycolic

  11. Fabrication and Characterization of Uranium-Molybdenum-Zirconium Alloys 

    E-print Network

    Woolum, Connor

    2014-12-12

    As part of a global effort to convert reactors that require highly enriched uranium to instead operate with low enriched uranium, monolithic fuel plates consisting of a U-Mo fuel meat with a zirconium foil barrier layer and clad in aluminum...

  12. Uranium in US surface, ground, and domestic waters. Volume 2

    SciTech Connect

    Drury, J.S.; Reynolds, S.; Owen, P.T.; Ross, R.H.; Ensminger, J.T.

    1981-04-01

    The report Uranium in US Surface, Ground, and Domestic Waters comprises four volumes. Volumes 2, 3, and 4 contain data characterizing the location, sampling date, type, use, and uranium conentrations of 89,994 individual samples presented in tabular form. The tabular data in volumes 2, 3, and 4 are summarized in volume 1 in narrative form and with maps and histograms.

  13. Laser fluorometric analysis of plants for uranium exploration

    USGS Publications Warehouse

    Harms, T.F.; Ward, F.N.; Erdman, J.A.

    1981-01-01

    A preliminary test of biogeochemical exploration for locating uranium occurrences in the Marfa Basin, Texas, was conducted in 1978. Only 6 of 74 plant samples (mostly catclaw mimosa, Mimosa biuncifera) contained uranium in amounts above the detection limit (0.4 ppm in the ash) of the conventional fluorometric method. The samples were then analyzed using a Scintrex UA-3 uranium analyzer* * Use of trade names in this paper is for descriptive purposes only and does not constitute endorsement by the U.S. Geological Survey. - an instrument designed for direct analysis of uranium in water, and which can be conveniently used in a mobile field laboratory. The detection limit for uranium in plant ash (0.05 ppm) by this method is almost an order of magnitude lower than with the fluorometric conventional method. Only 1 of the 74 samples contained uranium below the detection limit of the new method. Accuracy and precision were determined to be satisfactory. Samples of plants growing on mineralized soils and nonmineralized soils show a 15-fold difference in uranium content; whereas the soils themselves (analyzed by delayed neutron activation analysis) show only a 4-fold difference. The method involves acid digestion of ashed tissue, extraction of uranium into ethyl acetate, destruction of the ethyl acetate, dissolution of the residue in 0.005% nitric acid, and measurement. ?? 1981.

  14. Nuclear power fleets and uranium resources recovered from phosphates

    SciTech Connect

    Gabriel, S.; Baschwitz, A.; Mathonniere, G. [CEA, DEN/DANS/I-tese, F-91191 Gif-sur-Yvette (France)

    2013-07-01

    Current light water reactors (LWR) burn fissile uranium, whereas some future reactors, as Sodium fast reactors (SFR) will be capable of recycling their own plutonium and already-extracted depleted uranium. This makes them a feasible solution for the sustainable development of nuclear energy. Nonetheless, a sufficient quantity of plutonium is needed to start up an SFR, with the plutonium already being produced in light water reactors. The availability of natural uranium therefore has a direct impact on the capacity of the reactors (both LWR and SFR) that we can build. It is therefore important to have an accurate estimate of the available uranium resources in order to plan for the world's future nuclear reactor fleet. This paper discusses the correspondence between the resources (uranium and plutonium) and the nuclear power demand. Sodium fast reactors will be built in line with the availability of plutonium, including fast breeders when necessary. Different assumptions on the global uranium resources are taken into consideration. The largely quoted estimate of 22 Mt of uranium recovered for phosphate rocks can be seriously downscaled. Based on our current knowledge of phosphate resources, 4 Mt of recoverable uranium already seems to be an upper bound value. The impact of the downscaled estimate on the deployment of a nuclear fleet is assessed accordingly. (authors)

  15. Fuel element recovery and its relationship to uranium scrap

    Microsoft Academic Search

    1958-01-01

    At the request of the manager of Process Engineering, a study was made of the fuel element recovery operation and its relationship to the HAPO uranium scrap losses. Three fundamental questions formed the basis for this study. They are: What is the amount of the yearly uranium scrap loss at HAPO? What contribution does the existing fuel element recovery process

  16. Aquifer restoration at uranium in situ leach sites

    Microsoft Academic Search

    Frank S. Anastasi; Roy E. Williams

    1984-01-01

    In situ mining of uranium involves injection of a leaching solution (lixiviant) into an ore-bearing aquifer. Frequently, the ground water in the mined aquifer is a domestic or livestock water supply. As the lixiviant migrates through the ore body, uranium and various associated elements such as arsenic, selenium, molybdenum, vanadium and radium-226 are mobilized in the ground water. Aquifer restoration

  17. Mortality from lung cancer in Ontario uranium miners

    Microsoft Academic Search

    R A Kusiak; A C Ritchie; J Muller; J Springer

    1993-01-01

    Mortality from lung cancer was greater in Ontario uranium miners than in the general male population of Ontario (observed = 152, expected = 67.6, standardised mortality ratio 225, 95% confidence interval 191-264). Part of the excess of lung cancer may be because the proportion of men who are smokers or have smoked is greater in uranium miners than in Ontario

  18. Adsorption study for uranium in Rocky Flats groundwater

    SciTech Connect

    Laul, J.C.; Rupert, M.C. [EG and G Rocky Flats, Inc., Golden, CO (United States); Harris, M.J. [Science Applications International Corp., Golden, CO (United States); Duran, A. [Environmental Protection Agency, Denver, CO (United States)

    1995-01-01

    Six adsorbents were studied to determine their effectiveness in removing uranium in Rocky Flats groundwater. The bench column and batch (Kd) tests showed that uranium can be removed (>99.9%) by four adsorbents. Bone Charcoal (R1O22); F-1 Alumina (granular activated alumina); BIOFIX (immobilized biological agent); SOPBPLUS (mixed metal oxide); Filtrasorb 300 (granular activated carbon); and Zeolite (clinoptilolite).

  19. Re-examining uranium supply and demand: New insights

    Microsoft Academic Search

    Sondès Kahouli

    2011-01-01

    In this paper, we derive a simultaneous system of equations which aims at analysing the uranium supply and demand. In addition to reviewing and updating previous studies dealing with the uranium market analysis, in particular Amavilah (1995), the contribution of the paper lies in putting attention to some questions which are still either controversial or unanswered. They are especially related

  20. Radioactive wastes from uranium mining enterprises and their environmental effects

    Microsoft Academic Search

    V. N. Mosinets

    1991-01-01

    content in the ore and the activity of the geochemical processes occurring in the deposit prior to mining, particularly natural leaching resulting from the shift in the equilibrium of uranium with regard to its decay products [i]. The level of radioactivity of the wastes from the exploitation of known uranium deposits is usually low, especially if it is compared with