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1

Uranium dioxide electrolysis  

DOEpatents

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

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

2009-12-29

2

Dry process fluorination of uranium dioxide using ammonium bifluoride  

E-print Network

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 ...

Yeamans, Charles Burnett, 1978-

2003-01-01

3

Thermodynamic properties of uranium dioxide  

SciTech Connect

In order to provide reliable and consistent data on the thermophysical properties of reactor materials for reactor safety studies, this revision is prepared for the thermodynamic properties of the uranium dioxide portion of the fuel property section of the report Properties for LMFBR Safety Analysis. Since the original report was issued in 1976, there has been international agreement on a vapor pressure equation for the total pressure over UO/sub 2/, new methods have been suggested for the calculation of enthalpy and heat capacity, and a phase change at 2670 K has been proposed. In this report, 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.

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

1981-04-01

4

Anisotropic thermal conductivity in uranium dioxide.  

PubMed

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

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

5

Conversion of Uranium Oxide into Nitrate with Nitrogen Dioxide  

NASA Astrophysics Data System (ADS)

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 % of the uranium dioxide, whose initial feed amount was 0.3 g, was converted into a water soluble compound. Based on an XRD analysis of the compound, uranyl nitrate trihydrate (UO2(NO3)2·3H2O) was confirmed.

Sawada, Kayo; Hirabayashi, Daisuke; Enokida, Youichi; Yamamoto, Ichiro

6

Uranium dioxide dissolution under acidic aqueous conditions  

SciTech Connect

Understanding of the long-term dissolution of waste forms in groundwater is required for the safe disposal of high level nuclear waste in a geologic repository, because waste-form radionuclides could be released by dissolution and transported in groundwater. The dissolution of the uranium dioxide (UO{sub 2}) matrix in spent nuclear fuel is considered the rate-limiting step for release of radioactive fission products. The intrinsic UO{sub 2} dissolution rate sets an upper limit on the aqueous radionuclide release rate. Unsaturated spent fuel tests have shown that pH`s of leachates have decreased to a range of 4 to 6, presumably due to air radiolysis that oxidizes nitrogen, producing nitric acid. Dissolution rates under such acidic conditions may be different than those previously reported for alkaline groundwater conditions. No dissolution rate measurements of UO{sub 2} or spent fuel have been reported for acidic conditions possibly relevant to a geologic repository. The purpose of our work has been to measure the intrinsic dissolution rates of uranium dioxide under acidic conditions that are relevant to a repository and allow for modeling. Experiments have been completed at room-temperature and 75 C, pH`s of 4 and 6, and air and oxygen saturated aqueous solutions. These are compared with earlier work on spent fuel and UO{sub 2} using alkaline solutions.

Steward, S.A.; Mones, E.T.

1995-11-20

7

Design of a Uranium Dioxide Spheroidization System  

NASA Technical Reports Server (NTRS)

The plasma spheroidization system (PSS) is the first process in the development of tungsten-uranium dioxide (W-UO2) fuel cermets. The PSS process improves particle spherocity and surface morphology for coating by chemical vapor deposition (CVD) process. Angular fully dense particles melt in an argon-hydrogen plasma jet at between 32-36 kW, and become spherical due to surface tension. Surrogate CeO2 powder was used in place of UO2 for system and process parameter development. Particles range in size from 100 - 50 microns in diameter. Student s t-test and hypothesis testing of two proportions statistical methods were applied to characterize and compare the spherocity of pre and post process powders. Particle spherocity was determined by irregularity parameter. Processed powders show great than 800% increase in the number of spherical particles over the stock powder with the mean spherocity only mildly improved. It is recommended that powders be processed two-three times in order to reach the desired spherocity, and that process parameters be optimized for a more narrow particles size range. Keywords: spherocity, spheroidization, plasma, uranium-dioxide, cermet, nuclear, propulsion

Cavender, Daniel P.; Mireles, Omar R.; Frendi, Abdelkader

2013-01-01

8

Helium Migration Mechanisms in Polycrystalline Uranium Dioxide  

SciTech Connect

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)

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

9

Irradiation of TZM: uranium dioxide fuel pin at 1700 K  

Microsoft Academic Search

A fuel pin clad with TZM and containing solid pellets of uranium dioxide ; was fission-heated in a static helium-cooled capsule at a maximum surface ; temperature of 1700 deg K for 1000 h and to a total burnup of 2.0% of the uranium-; 235. The results of the postirradiation examination indicated: (1) A transverse, ; intergranular failure of the

1973-01-01

10

Fission gas bubble behaviour in uranium dioxide  

NASA Astrophysics Data System (ADS)

A theoretical model developed to study the gas bubble evolution in nuclear materials has been used to analyze experiments on uranium dioxide irradiated to low burnups (0.1 and 0.4 at%), in which fission gas bubble size distributions were measured following out-of-pile isothermal anneals. Following irradiation, the UO 2 was annealed for 1 or 6 h each at temperatures between 1303 and 1973 K and then thinned for transmission electron microscopy observation of the bubble size distributions. The model is based on the assumption, that the coalescence of the moving bubbles is the main mechanism defining gas porosity development under these conditions. The gas bubbles are assumed to be in equilibrium and their motion is assumed to be caused by random migration. The calculations show that the observed bubble size distributions may be reproduced on the base of the bubble growth mechanisms considered. The joint action of bubble surface and volume diffusion mechanisms can explain both the general nature of the experimental distributions and their perculiarities, in particularly the bimodal bubble size distribution observed after annealing at 1673 K. The choice of appropriate values as input parameters into the model is discussed.

Chkuaseli, V. F.; Matzke, Hj.

11

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

DOEpatents

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.

Stinton, David P. (Knoxville, TN)

1983-01-01

12

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

E-print Network

uranium dioxide Abdul-Majeed Azad * Department of Chemical and Environmental Engineering, The University, reliable data on the sound prop- agation velocity in molten uranium dioxide have been obtained. An equation 61:98 ffiffiffiffi T p : ð1� For stoichiometric uranium oxide (O/U = 2.00) values of 3070 K [6], 3115

Azad, Abdul-Majeed

13

Standard specification for sintered (Uranium-Plutonium) dioxide pellets  

E-print Network

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...

American Society for Testing and Materials. Philadelphia

2001-01-01

14

Interaction of uranium dioxide with molten zircaloy  

SciTech Connect

Laboratory experiments in which gram quantities of molten Zircaloy were held in contact with UO/sub 2/ for known times (20 to 600 s) and temperatures (1900 - 2200/sup 0/C) were conducted. Sections were examined by optical microscopy, electron microprobe, scanning Auger microscopy, and X-ray fluorescence spectroscopy. In the first experiment, the molten metal was contained in a UO/sub 2/ crucible. The dissolution rate in this system was found to be dominated by natural convention in the melt driven by density gradients established by the dissolving uranium. The mechanism of the interaction also was observed to involve penetration and detachment of the grains of the oxide by the molten metal. Similar tests with single-crystal UO/sub 2/ specimens showed similar dissolution behavior. Less severe attach occurred because of the absence of grain boundaries, although subgrain boundaries or dislocations provided high-diffusivity pathways for preferential oxygen removal. In the third type of test, a disk of UO/sub 2/ was placed at the bottom of a ThO/sub 2/ crucible. This arrangement prevented establishment of unstable density gradients in the liquid phase, resulting in a purely diffusion-controlled interaction. A remarkable seven-region structure was observed in the quenched specimens. This structure could be explained by analysis of the quenching of the high-temperature interaction zone with the aid of the available ternary phase diagrams of the U-Zr-O system. The layers grew parabolically in time. The relevance of the data obtained to the melting on fuel pellets in a severe fuel damage accident was assessed.

Kim, Kyu Tae

1987-04-01

15

Alternative Anodes for the Electrolytic Reduction of Uranium Dioxide  

NASA Astrophysics Data System (ADS)

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.

Merwin, Augustus

16

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

E-print Network

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

Paris-Sud XI, Université de

17

Uranium dioxide reaction in CF 4/O 2 RF plasma  

NASA Astrophysics Data System (ADS)

Research on the fluorination reaction of UO 2 in CF 4/O 2 RF plasma is carried out at temperatures of up to 370°C under total pressure of 0.3 Torr. The reaction rates are investigated as functions of CF 4/O 2 ratio, plasma power, substrate temperature, and exposure time to the plasma. It is found that there exists an optimum CF 4/O 2 ratio of around four for the efficient etching, regardless of RF power and substrate temperature. According to the mass spectrometry it is revealed that the major reaction product is uranium hexa-fluoride UF 6. Some minor species such as UF 4 and UF 5 are probably generated parasitically. The highest etching reaction rate at 370°C under 150 W exceeds 1000 monolayers/min, which is equivalent to 0.4 ?m/min. Based on the experimental findings, dominant overall reaction of uranium dioxide in CF 4/O 2 plasma is determined: UO2+3/2 CF4+3/8 O2= UF6+3/2 CO2-x, where CO 2- x represents the undetermined mix of CO 2 and CO. The overall reaction follows a linear kinetics and is thus rate-determined by the surface reaction between the uranium atom in UO 2F 2 intermediates on the surface and incoming fluorine atoms or fluorine containing radicals. The activation energy of this reaction is derived as 12.1 kJ/mol.

Kim, Yong-soo; Min, Jin-young; Bae, Ki-kwang; Yang, Myung-seung

18

Chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade uranium dioxide powders and pellets  

SciTech Connect

Uranium dioxide is used as a nuclear-reactor fuel. In order to be suitable for this purpose, the material must meet certain criteria for uranium content, stoichiometry, isotopic composition, impurity content. The following analytical procedures, which are described in detail, are designed to show whether or not a given material meets specifications: uranium by ferrous sulfate reduction in phosphoric acid and dichromate titration method; uranium and oxygen uranium atomic ratio by the ignition (gravimetric) impurity correction method; oxygen to uranium atomic ratios by the polarographic method; carbon (total) by direct combustion-thermal conductivity method; total chlorine and fluorine by pyrohydrolysis ion-selective electrode method; moisture by the coulometric, electrolytic moisture analyzer method; nitrogen by the Kjeldahl method; total sulfur by distillation-spectrophotometric method; isotopic uranium composition by multiple-filament surface-ionization mass spectrometric method; spectrochemical determination of trace elements in high-purity uranium dioxide; volatile fluoride impurities by spectrochemical method using the rotating-disk spark technique; spectrochemical determination of silver by gallium oxide carrier D-C arc technique; rare earths by copper spark-spectrochemical method; impurity elements by a spark-source mass spectrographic method; surface area by nitrogen absorption method; total gas in reactor-grade uranium dioxide pellets; thorium and rare earth elements by spectroscopy; hydrogen by inert gas fusion; and uranium isotopic analysis by mass spectrometry. (JMT)

Not Available

1981-01-01

19

Irradiation of TZM: Uranium dioxide fuel pin at 1700 K  

NASA Technical Reports Server (NTRS)

A fuel pin clad with TZM and containing solid pellets of uranium dioxide was fission heated in a static helium-cooled capsule at a maximum surface temperature of 1700 K for approximately 1000 hr and to a total burnup of 2.0 percent of the uranium-235. The results of the postirradiation examination indicated: (1) A transverse, intergranular failure of the fuel pin occurred when the fuel pin reached 2.0-percent burnup. This corresponds to 1330 kW-hr/cu cm, where the volume is the sum of the fuel, clad, and void volumes in the fuel region. (2) The maximum swelling of the fuel pin was less than 1.5 percent on the fuel-pin diameter. (3) There was no visible interaction between the TZM clad and the UO2. (4) Irradiation at 1700 K produced a course-grained structure, with an average grain diameter of 0.02 centimeter and with some of the grains extending one-half of the thickness of the clad. (5) Below approximately 1500 K, the irradiation of the clad produced a moderately fine-grained structure, with an average grain diameter of 0.004 centimeter.

Mcdonald, G. E.

1973-01-01

20

Pathway and energetics of xenon migration in uranium dioxide  

NASA Astrophysics Data System (ADS)

Using a combination of density functional theory (DFT), classical potentials, molecular dynamics, and nudged elastic band (NEB) calculations, we explore the diffusion of xenon in uranium dioxide (UO2). We compare migration barriers of empirical potentials with DFT by performing NEB calculations and subsequently we use the DFT-validated empirical potentials to calculate vacancy clusters, with and without xenon, to determine the migration path and barrier of xenon in bulk UO2. We find the following: (i) Two empirical potentials out of four tested agree qualitatively with DFT derived energetics for Schottky defect migration; (ii) through the use of molecular dynamics with empirical potentials, we have found a path for the diffusion of xenon-tetravacancy clusters (Xe+2VU+2VO); (iii) this path has an energy barrier significantly lower than previously reported paths by nearly 1 eV; (iv) we examine the physical contributions to the migration pathway and find the barrier is largely electrostatic and that xenon contributes very little to the barrier height; (v) once a uranium vacancy attaches to a xenon-Schottky defect, the resulting xenon-tetravacancy cluster is strongly bound; and (vi) as xenon in a tetravacancy, a xenon-double Schottky defect can diffuse in a concerted manor with a comparable barrier to xenon in a tetravacancy, but two of the oxygen vacancies are only weakly bound to the defect.

Thompson, Alexander E.; Wolverton, C.

2013-03-01

21

Molecular Dynamics Simulation of Thermodynamic Properties in Uranium Dioxide  

SciTech Connect

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

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

2014-03-01

22

Elementary excitations in uranium dioxide: Unravelling the tangle  

NASA Astrophysics Data System (ADS)

In solids with d- and f-electrons, under certain conditions the orbitals align to form an ordered structure. Collective excitations breaking this arrangement can take the form of oscillations of electric quadrupoles, the so-called quadrupolar waves. These represent a propagating pattern of charge densities implying a modulation of quadrupolar moments. Quadrupolar waves constitute a major component of the dynamics of uranium dioxide in its magneto-quadrupolar ordered phase. Together with spin-waves and phonons, these produce a very complex spectrum of elementary excitations having hybrid character over most of the Brillouin zone. Although neutron scattering spectra only reveal the tip of the iceberg of this spectrum, its complete and detailed modelling is needed to understand such experiments. Distinct roles of Jahn-Teller and superexchange mechanisms as sources of quadrupolar interactions can be clearly identified by such modelling. xml:lang="fr"

Santini, Paolo

2014-08-01

23

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

PubMed

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

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

2014-01-01

24

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

25

Spectrophotometric determination of nonstoichiometry in hyperstoichiometric uranium dioxide  

SciTech Connect

Uranium dioxide is widely used as a nuclear fuel and usually exists as hyperstoichiometric UO/sub 2+x/. In the described method UO/sub 2+x/ is dissolved in warm concentrated phosphoric acid saturated with sodium sulfate at room temperature to prevent the air oxidation of U(IV). The concentrations of U(VI) and U(IV) are directly determined by means of the absorbance of the two species at two specific wavelengths 420 and 665 nm, respectively. The results obtained are precise to +/- 0.002 O/U units and have been compared with those obtained from gravimetric titrimetry employing potentiometric end point detection. The O/U ratio determined by the two procedures agrees within 0.004 O/U units. The method has been employed to determine O/U ratio in near stoichiometric UO/sub 2/ (2.039) as well as in U/sub 3/O/sub 8/ (2.670). The developed spectrophotometric method is simple and fast and does not require inert atmosphere.

Ahmed, M.K.; Sreenivasan, N.L.

1986-10-01

26

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

SciTech Connect

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.

Nelson, Andrew T. [Los Alamos National Laboratory

2012-08-30

27

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

E-print Network

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.

Igor Iosilevskiy; Victor Gryaznov

2010-05-23

28

Process for continuous production of metallic uranium and uranium alloys  

DOEpatents

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

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

1995-06-06

29

Process for continuous production of metallic uranium and uranium alloys  

DOEpatents

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

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

1995-01-01

30

Effects of different parameters on the densities of uranium dioxide and uranium dioxide-gadolinium oxide fuels produced by the sol-gel technique  

Microsoft Academic Search

Uranium dioxide-gadolinium oxide fuel was produced by the sol-gel technique. The effects of different parameters such as calcination and reduction temperature, compaction pressure, particle size of powder, type of binder, sintering temperature, sintering atmosphere, and duration of sintering on pore size distribution were investigated. The experiments were carried out on three different fuels, (a) pure urania, (b) urania-gadolinia (10%), and

G. Guenduez; I. Uslu; I. Oenal; H. H. Durmazucar; T. Oeztuerk; A. A. Aksit; B. Kopuz; S. Can; R. Uzmen

1995-01-01

31

THE OXIDATION AND RELEASE OF IODINE131 FROM URANIUM SLUGS OXIDIZING IN AIR AND CARBON DIOXIDE  

Microsoft Academic Search

Experiments to determine the oxidation rate, particle size distribution ; of oxide, and release of I¹³¹ from one kilogram, trace irradiated uranium ; slugs oxidizing at temperatures up to 1000 deg C in air and carbon dioxide are ; described. The release of iodine as a result of rapid melting of uranlum ls also ; investigated. lt is concluded that

W. J. Megaw; R. C. Chadwick; A. C. Wells; J. E. Bridges

1961-01-01

32

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

Microsoft Academic Search

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,

Charles W. Forsberg; M. Jonathan Haire

33

Enriched Uranium  

NSDL National Science Digital Library

This Wikipedia website provides information about the various concentrations of uranium used for different applications. Topics include a brief description of the grades of uranium and methods of isotope separation. There are also links to other aspects of uranium enrichment and related information. This information lays the foundation for informed discussion about the potential of nuclear energy and the risks of nuclear proliferation.

Wikipedia

34

Particle-size distribution in capacitor discharge vaporization of uranium dioxide  

Microsoft Academic Search

A homogeneous nucleation-condensation growth model was developed for calculating particle-size distributions measured in capacitor discharge vaporization (CDV) experiments conducted at the Oak Ridge National Laboratory. Uranium dioxide pellets were partially vaporized in an argon environment by rapid energy deposition through capacitor discharge. This was followed by rapid expansion and subsequent condensation of the UOâ vapor. Measured primary particle-size distributions of

K. Chen; C. A. Erdman; M. F. Kennedy; A. B. Reynolds

1983-01-01

35

Multipolar, magnetic, and vibrational lattice dynamics in the low-temperature phase of uranium dioxide  

Microsoft Academic Search

We report the results of inelastic neutron scattering experiments performed with triple-axis spectrometers to investigate the low-temperature collective dynamics in the ordered phase of uranium dioxide. The results are in very good agreement with the predictions of mean-field random phase approximation calculations, emphasizing the importance of multipolar superexchange interactions. By comparing neutron scattering intensities in different polarization channels and at

R. Caciuffo; P. Santini; S. Carretta; G. Amoretti; A. Hiess; N. Magnani; L.-P. Regnault; G. H. Lander

2011-01-01

36

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

Microsoft Academic Search

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

Charles W. Forsberg; Les R. Dole

37

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

NASA Astrophysics Data System (ADS)

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.

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

2003-03-01

38

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

SciTech Connect

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

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

2013-10-01

39

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

SciTech Connect

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

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

2013-07-01

40

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

SciTech Connect

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.

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

41

Electron energy loss spectroscopy investigation through a nano ablated uranium dioxide sample.  

PubMed

A lamella of uranium dioxide (?10 × ?10 × ?0.02-0.20 ?m) was produced by focused ion beam for transmission electron and electron energy loss spectroscopy (EELS) examinations. This sample allows quantitative analysis of the EEL spectra recorded for UO? as a function of the thickness. The M, N, O and P edges were recorded over zero loss to 4000 eV loss. The edges allow reconstruction of the electronic transitions, the lowest energy loss edges for P transitions corresponds to P3 electron transition (17.2 eV) from U6p3/2 level. The edge analysis allows also better interpretation of the loss spectrum with identification of the plasmon peak of the core electron transition edges. In addition, the energy lost was studied through a range of thicknesses going from ?20 to ?200 nm to derive the electron mean free path and cross section for inelastic scattering in the plasmon part of the spectrum. The mean free path of inelastic electron for uranium dioxide is compared with that reported earlier for other oxides from Be to Bi and for 200 keV incidents electrons. The present study emphasises the potential of combining FIB and EELS for the analysis of actinide compounds. PMID:23598145

Degueldre, Claude; Schaeublin, Robin; Krbanjevic, Julijana; Minikus, Eugenia

2013-03-15

42

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

PubMed

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 U(4+) with Cr(3+) 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. PMID:25109302

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

2014-09-01

43

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

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

44

Uranium Phosphates  

NASA Astrophysics Data System (ADS)

The methods of preparation, stability in solution and in the solid state, and composition of the crystalline hydrates of uranyl and uranium(IV) orthophosphates and condensed phosphates have been reviewed. The structures of these compounds have been discussed; they are three-dimensional polymers with a uranyl-phosphate framework. The polymerisation of the phosphate anion on thermal decomposition has been discussed. Condensed uranyl polyphosphates are unstable when kept, and are capable of undergoing dehydration, the extent of which increases with increase in the length of the phosphate chain and increase in the uranium concentration. The bibliography contains 199 references.

Kobets, L. V.; Umreiko, D. S.

1983-06-01

45

The critical point data of refractory metals, aluminum oxide and uranium dioxide using the hoch-arpshofen method  

NASA Astrophysics Data System (ADS)

The Hoch-Arpshofen method was used to determine the critical constants of titanium, molybdenum, aluminum oxide and uranium dioxide. In this method the density of the liquid as a function of the temperature (but not necessarily close to the critical temperature) is required to obtain the critical temperature T c and the critical density D c. The values obtained are:

Hoch, Michael

1988-05-01

46

Machining of uranium and uranium alloys  

SciTech Connect

Uranium and uranium alloys can be readily machined by conventional methods in the standard machine shop when proper safety and operating techniques are used. Material properties that affect machining processes and recommended machining parameters are discussed. Safety procedures and precautions necessary in machining uranium and uranium alloys are also covered. 30 figures.

Morris, T.O.

1981-12-14

47

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

SciTech Connect

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.

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

1999-06-18

48

First principles computational modeling of the surface properties of uranium dioxide  

NASA Astrophysics Data System (ADS)

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.

Hoover, Megan

49

Etching of uranium dioxide in nitrogen trifluoride RF plasma glow discharge  

NASA Astrophysics Data System (ADS)

A series of room temperature, low pressure (10.8 to 40 Pa), low power (25 to 210 W) RF plasma glow discharge experiments with UO2 were conducted to demonstrate that plasma treatment is a viable method for decontaminating UO2 from stainless steel substrates. Experiments were conducted using NF3 gas to decontaminate depleted uranium dioxide from stainless-steel substrates. Results demonstrated that UO2 can be completely removed from stainless-steel substrates after several minutes processing at under 200 W. At 180 W and 32.7 Pa gas pressure, over 99% of all UO2 in the samples was removed in just 17 minutes. The initial etch rate in the experiments ranged from 0.2 to 7.4 mum/min. Etching increased with the plasma absorbed power and feed gas pressure in the range of 10.8 to 40 Pa. A different pressure effect on UO2 etching was also noted below 50 W in which etching increased up to a maximum pressure, ˜23 Pa, then decreased with further increases in pressure. A computer simulation, CHEMKIN, was applied to predict the NF3 plasma species in the experiments. The code was validated first by comparing its predictions of the NF3 plasma species with mass spectroscopy etching experiments of silicon. The code predictions were within +/-5% of the measured species concentrations. The F atom radicals were identified as the primary etchant species, diffusing from the bulk plasma to the UO2 surface and reacting to form a volatile UF6, which desorbed into the gas phase to be pumped away. Ions created in the plasma were too low in concentration to have a major effect on etching, but can enhance the etch rate by removing non-volatile reaction products blocking the reaction of F with UO2. The composition of these non-volatile products were determined based on thermodynamic analysis and the electronic structure of uranium. Analysis identified possible non-volatile products as the uranium fluorides, UF2-5, and certain uranium oxyfluorides UO2F, UO2F2, UOF3, and UOF 4 which form over the UO2 surface. Successive reactions between these products and F atoms lead to the formation of UF6. The UF 6 has a vapor pressure of 24 kPa, well above the operating pressure at the gas temperature (˜300 K) of the plasma, and, as a consequence, desorbs into the gas phase. The other Intermediate fluorides and oxyfluorides are solids and remain on the surface, eventually slowing or blocking the etch reaction as they accumulate. These results explain why when power was too low, the etch reactions completely stopped before all detectable UO2 could be fully etched. Comparison of UO2 with previously measured PuO2 etch rates showed that the removal of UO2 and PuO2were comparable and differences could be accounted for by differences in experimental conditions. The chemistry and reaction thermodynamics of UO2 have many parallels to those of PuO2, such as similar vapor pressures at room temperature (24 vs. 14 kPa) and favorable Gibbs free energy of formation of many species. (Abstract shortened by UMI.)

Veilleux, John Mark

1999-10-01

50

Uranium: a basic evaluation  

Microsoft Academic Search

All energy sources and technologies, including uranium and the nuclear industry, are needed to provide power. Public misunderstanding of the nature of uranium and how it works as a fuel may jeopardize nuclear energy as a major option. Basic chemical facts about uranium ore and uranium fuel technology are presented. Some of the major policy decisions that must be made

Crull

2009-01-01

51

Separation and mass spectrometry of nanogram quantities of uranium and thorium from thorium-uranium dioxide fuels  

SciTech Connect

A microchemical procedure was developed for the separation and isotopic analysis of U and Th from irradiated (Th,U)O/sub 2/ fuel. The separation procedure consisted of two stages; in the first a tributyl phosphate impregnated resin bead was equilibrated with the dissolved fuel in 0.08 M HF/6 M HNO/sub 3/ solution. The bead sorbed approximately 1.7 ..mu..g of U and 4.8..mu..g of Th and provided good separation of these from the fission products. In the second stage, the U and Th were back-extracted into 0.025 M HF/8 M HNO/sub 3/ solution, which contained a small anion-exchange membrane disk. The disk adsorbed approximately 14 ng of U and 45 ng of Th, and subsequently was transferred to the ionizing filament of a thermal-ionization mass spectrometer and covered with a starch deposit. Sensitivities were sufficiently high for sequential analysis of these quantities of Th and U from a single disk. Isotopic data obtained for a combined U and Th standard showed excellent agreement with certified values: overall bias and precision were < 0.03% and 0.2% relative standard deviation, respectively, for both elements. The applicability of the procedure to uranium fuels was also demonstrated. 6 figures, 2 tables.

Green, L.W.; Elliot, N.L.; Longhurst, T.H.

1983-12-01

52

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

NASA Astrophysics Data System (ADS)

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.

Cavender, Daniel

53

Results of Uranium Dioxide-Tungsten Irradiation Test and Post-Test Examination  

NASA Technical Reports Server (NTRS)

A uranium dioxide (UO2) fueled capsule was fabricated and irradiated in the NASA Plum Brook Reactor Facility. The capsule consisted of two bulk UO2 specimens clad with chemically vapor deposited tungsten (CVD W) 0.762 and 0.1016 cm (0.030-and 0.040-in.) thick, respectively. The second specimen with 0.1016-cm (0.040-in.) thick cladding was irradiated at temperature for 2607 hours, corresponding to an average burnup of 1.516 x 10 to the 20th power fissions/cu cm. Postirradiation examination showed distortion in the bottom end cap, failure of the weld joint, and fracture of the central vent tube. Diametral growth was 1.3 percent. No evidence of gross interaction between CVD tungsten or arc-cast tungsten cladding and the UO2 fuel was observed. Some of the fission gases passed from the fuel cavity to the gas surrounding the fuel specimen via the vent tube and possibly the end-cap weld failure. Whether the UO2 loss rates through the vent tube were within acceptable limits could not be determined in view of the end-cap weld failure.

Collins, J. F.; Debogdan, C. E.; Diianni, D. C.

1973-01-01

54

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

SciTech Connect

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.

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

55

Ab initio construction of interatomic potentials for uranium dioxide across all interatomic distances  

NASA Astrophysics Data System (ADS)

We provide a methodology for generating interatomic potentials for use in classical molecular-dynamics simulations of atomistic phenomena occurring at energy scales ranging from lattice vibrations to crystal defects to high-energy collisions. A rigorous method to objectively determine the shape of an interatomic potential over all length scales is introduced by building upon a charged-ion generalization of the well-known Ziegler-Biersack-Littmark universal potential that provides the short- and long-range limiting behavior of the potential. At intermediate ranges the potential is smoothly adjusted by fitting to ab initio data. Our formalism provides a complete description of the interatomic potentials that can be used at any energy scale, and thus, eliminates the inherent ambiguity of splining different potentials generated to study different kinds of atomic-materials behavior. We exemplify the method by developing rigid-ion potentials for uranium dioxide interactions under conditions ranging from thermodynamic equilibrium to very high atomic-energy collisions relevant for fission events.

Tiwary, P.; van de Walle, A.; Grønbech-Jensen, N.

2009-11-01

56

Extraction of uranium from uranium oxides (UO(x)) using beta-diketones and alkyl phosphates dissolved in supercritical carbon dioxide  

NASA Astrophysics Data System (ADS)

In this dissertation, the development of a supercritical fluid extraction (SFE) process for the removal of uranium directly from a solid, crystalline lattice is described. Uranium was chosen as the metal of interest due to its importance to the nuclear industry. While this work was conducted in an attempt to further develop metals extraction using SFE, it has as its main goal the reduction of waste associated with nuclear fuel reprocessing. In this study it was discovered that the beta-diketonate ligand thenoyltrifluoroacetyl-acetone (TTA) was most effective in complexing uranium directly from UOsb3. Approximately 70% of the UOsb3 is converted to uranyl-TTA complex in a typical extraction. Increased solubility of the uranyl-TTA complex (UOsb2(TTA)sb2{*}Hsb2Orbrack was achieved through the formation of adducts with the organophosphorous reagents TBP, TOPO, TPPO and TBPO. In competitive extraction experiments, uranium was efficiently extracted from a mixture of six metal oxides through the formation of UOsb2(TTA)sb2{*}TBP in 2% TBP modified COsb2. Crystal structures of UOsb2(TTA)sb2{*}Hsb2O,\\ UOsb2(TTA)sb2{*}EtOH and UOsb2(TTA)sb2{*}TBP were obtained. The TTA complexes of iron (Fe(TTA)sb3rbrack and thorium (Th(TTA)sb4rbrack were effectively separated from the uranyl complex in SF COsb2 by changing fluid density. It was also shown that the uranyl and thorium complexes could be separated from each other using the same technique. A method for the synthesis of UOsb2(TTA)sb2{*}Hsb2O starting with UOsb3 in hexane is described. A view cell was used to obtain the solubility of acetylacetone (ACAC), trifluoroacetylacetone (TFA), hexafluoroacetylacetone (HFA) and TTA in supercritical fluid (SF) carbon dioxide under varying conditions. Volatility and increased fluorination influence the degree to which each ligand is soluble in SF COsb2. In addition, the equilibrium between the keto and enol tautomers of ACAC, TFA and HFA dissolved in SF COsb2 was determined using sp1H NMR. The observed trends for all ligands studied correlate well with extraction results for this class of compounds.

Phelps, Cindy Lou

57

Uranium industry annual 1998  

SciTech Connect

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.

NONE

1999-04-22

58

Uranium industry annual 1994  

SciTech Connect

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

NONE

1995-07-05

59

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

NASA Astrophysics Data System (ADS)

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.

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

2013-07-01

60

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...

61

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

62

Fabrication of uranium dioxide ceramic pellets with controlled porosity from oxide microspheres  

NASA Astrophysics Data System (ADS)

This study concerns the fabrication of uranium oxide pellets using the powder-free process called Calcined Resin Microsphere Pelletization (CRMP). Details are given about oxide microsphere synthesis and particularly about loading operation and heat treatments. The fabrication of ceramic pellets is also described and discussed. Results showed that this process allows the preparation of either dense or porous pellets by mixing U3O8 and UO2-like microspheres before pressing and sintering.

Remy, E.; Picart, S.; Delahaye, T.; Jobelin, I.; Dugne, O.; Bisel, I.; Blanchart, P.; Ayral, A.

2014-05-01

63

Method for converting uranium oxides to uranium metal  

DOEpatents

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.

Duerksen, Walter K. (Norris, TN)

1988-01-01

64

Probing Surface Oxidation of Reduced Uranium Dioxide Thin Film Using Synchrotron Radiation  

SciTech Connect

The work presents a study of the formation of defects created by argon ion sputtering of UO{sub 2} thin film surfaces using high-resolution X-ray photoelectron spectroscopy with photon energy of 625 eV. Stable-defected surfaces of UO{sub 2-x} were monitored by the uranium core level lines found at the low-binding energy side of the U{sup +4} features. The lower end of these states gave binding energies at 377.1 and 387.7 eV attributed to U4f{sub 7/2} and U4f{sub 5/2} core levels peaks, respectively, for metallic uranium (U{sup {circ}}). In between both states (U{sup {circ}} and U{sup +4}), the clear presence of other electronic states is observed. These lines are attributed to intermediate, metastable states of uranium ions between U{sup {circ}} and U{sup +4}. Temperature-programmed X-ray photoelectron spectroscopy is performed to observe the oxidation process of these reduced states with increasing temperature. The increase in the U{sup +4} intensity is not correlated with the decrease of U ions signal with lower oxidation states indicating that the limitation is the photoelectron escape depth. In other words, sputtering has created reduced clusters or ridges on the surface of average dimensions larger than the escape depth of the 4f photoelectron with kinetic energy of 225 eV. The activation energy for surface oxidation to U{sup +4} is {approx}20 kJ mol{sup -1}. This value is close to other values reported for vacancy-type diffusion mechanism in the fluorite structure.

Senanayake,S.; Waterhouse, G.; Chan, A.; Madey , T.; Mullins, D.; Idriss, H.

2007-01-01

65

Uranium hexafluoride public risk  

SciTech Connect

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

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

1994-08-01

66

31 CFR 540.317 - Uranium feed; natural uranium feed.  

Code of Federal Regulations, 2013 CFR

... 3 2013-07-01 2013-07-01 false Uranium feed; natural uranium feed. 540.317 Section 540.317 Money...CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS...

2013-07-01

67

31 CFR 540.317 - Uranium feed; natural uranium feed.  

Code of Federal Regulations, 2012 CFR

... 3 2012-07-01 2012-07-01 false Uranium feed; natural uranium feed. 540.317 Section 540.317 Money...CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS...

2012-07-01

68

31 CFR 540.317 - Uranium feed; natural uranium feed.  

... 3 2014-07-01 2014-07-01 false Uranium feed; natural uranium feed. 540.317 Section 540.317 Money...CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS...

2014-07-01

69

31 CFR 540.317 - Uranium feed; natural uranium feed.  

Code of Federal Regulations, 2011 CFR

... 3 2011-07-01 2011-07-01 false Uranium feed; natural uranium feed. 540.317 Section 540.317 Money...CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS...

2011-07-01

70

31 CFR 540.317 - Uranium feed; natural uranium feed.  

Code of Federal Regulations, 2010 CFR

... 3 2010-07-01 2010-07-01 false Uranium feed; natural uranium feed. 540.317 Section 540.317 Money...CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS...

2010-07-01

71

Nonmilitary applications of uranium  

SciTech Connect

Uranium and its alloys should be considered for any application where weight and/or strength is required, or where weight to volume is important. There is considerable literature on uranium and its alloys. The fear of handling metallic uranium should not be a factor. It is the least hazardous of all long-lived isotopes. Sound industrial hygiene practices will provide adequate protection. In general, safety controls are similar to those required for other heavy metals.

Polson, C.E.; Blasch, E.B.

1981-01-01

72

Preparation of uranium compounds  

SciTech Connect

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.

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

2013-02-19

73

Extraction of uranium from simulated ore by the supercritical carbon dioxide fluid extraction method with nitric acid-TBP complex.  

PubMed

The supercritical fluid extraction (SFE) method using CO(2) as a medium with an extractant of HNO(3)-tri-n-butyl phosphate (TBP) complex was applied to extract uranium from several uranyl phosphate compounds and simulated uranium ores. An extraction method consisting of a static extraction process and a dynamic one was established, and the effects of the experimental conditions, such as pressure, temperature, and extraction time, on the extraction of uranium were ascertained. It was found that uranium could be efficiently extracted from both the uranyl phosphates and simulated ores by the SFE method using CO(2). It was thus demonstrated that the SFE method using CO(2) is useful as a pretreatment method for the analysis of uranium in ores. PMID:17099273

Dung, Le Thi Kim; Imai, Tomoki; Tomioka, Osamu; Nakashima, Mikio; Takahashi, Kuniaki; Meguro, Yoshihiro

2006-11-01

74

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

SciTech Connect

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)

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

75

Uranium: A Dentist's perspective  

PubMed Central

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

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

2012-01-01

76

Uranium: A Dentist's perspective.  

PubMed

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

Toor, R S S; Brar, G S

2012-01-01

77

Uranium in river water  

Microsoft Academic Search

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

M. R. Palmer; J. M. Edmond

1993-01-01

78

World Uranium Reserves  

NSDL National Science Digital Library

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.

James Hopf

79

Uranium and Thorium  

ERIC Educational Resources Information Center

The results of President Carter's policy on non-proliferation of nuclear weapons are expected to slow the growth rate in energy consumption, put the development of the breeder reactor in question, halt plans to reprocess and recycle uranium and plutonium, and expand facilities to supply enriched uranium. (Author/MA)

Finch, Warren I.

1978-01-01

80

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

81

CHARACTERIZATION OF URANIUM, URANIUM OXIDE AND SILICON MULTILAYER THIN FILMS  

E-print Network

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

Hart, Gus

82

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

83

EPA Update: NESHAP Uranium Activities  

E-print Network

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

84

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

NASA Technical Reports Server (NTRS)

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.

Hickman, Robert; Broadway, Jeramie

2014-01-01

85

Spectrophotometric measurement of uranium(VI)-tributylphosphate complex in supercritical carbon dioxide.  

PubMed

UV-visible absorption spectra of uranium(VI)-tributylphosphate (U(VI)-TBP) complex dissolved in supercritical CO(2) at 40-60 degrees C and 100-250 kg cm(-2) were recorded. Wavelengths and molar extinction coefficients for the absorption peaks of U(VI)-TBP were determined and confirmed to be in good agreement with those of UO(2)(NO(3))(2)(TBP)(2) complex dissolved in organic solvents such as n-hexane. The absorbance at a given wavelength was proportional to the concentration of U(VI) species in supercritical CO(2), indicating a feasibility of in-situ determination of U(VI) concentration in CO(2) phase. A lower detection limit of U(VI)-TBP complex was estimated to be ca. 1x10(-3)M. The molar extinction coefficient of U(VI)-TBP in supercritical CO(2) decreased slightly with an increase of the density of CO(2) medium, suggesting that the solute-solvent interaction of U(VI)-TBP complex with CO(2) was affected by the density. On the basis of the spectra obtained, phase behavior and solubility of UO(2)(NO(3))(2)(TBP)(2)+H(NO(3))(TBP)+TBP in supercritical CO(2) were elucidated. PMID:18967193

Sasaki, T; Meguro, Y; Yoshida, Z

1998-08-01

86

India's Worsening Uranium Shortage  

SciTech Connect

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.

Curtis, Michael M.

2007-01-15

87

Method for the recovery of uranium values from uranium tetrafluoride  

DOEpatents

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.

Kreuzmann, A.B.

1982-10-27

88

Method for the recovery of uranium values from uranium tetrafluoride  

DOEpatents

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.

Kreuzmann, Alvin B. (Cincinnati, OH)

1983-01-01

89

31 CFR 540.316 - Uranium enrichment.  

...2014-07-01 2014-07-01 false Uranium enrichment. 540.316 Section 540...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.316 Uranium enrichment. The term uranium...

2014-07-01

90

31 CFR 540.316 - Uranium enrichment.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Uranium enrichment. 540.316 Section 540...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.316 Uranium enrichment. The term uranium...

2011-07-01

91

31 CFR 540.316 - Uranium enrichment.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Uranium enrichment. 540.316 Section 540...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.316 Uranium enrichment. The term uranium...

2013-07-01

92

31 CFR 540.316 - Uranium enrichment.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Uranium enrichment. 540.316 Section 540...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.316 Uranium enrichment. The term uranium...

2012-07-01

93

31 CFR 540.316 - Uranium enrichment.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Uranium enrichment. 540.316 Section 540...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.316 Uranium enrichment. The term uranium...

2010-07-01

94

Evaluation of refractory-metal-clad uranium nitride and uranium dioxide fuel pins after irradiation for times up to 10 450 hours at 990 C  

NASA Technical Reports Server (NTRS)

The effects of some materials variables on the irradiation performance of fuel pins for a lithium-cooled space power reactor design concept were examined. The variables studied were UN fuel density, fuel composition, and cladding alloy. All pins were irradiated at about 990 C in a thermal neutron environment to the design fuel burnup. An 85-percent dense UN fuel gave the best overall results in meeting the operational goals. The T-111 cladding on all specimens was embrittled, possibly by hydrogen in the case of the UN fuel and by uranium and oxygen in the case of the UO2 fuel. Tests with Cb-1Zr cladding indicate potential use of this cladding material. The UO2 fueled specimens met the operational goals of less than 1 percent cladding strain, but other factors make UO2 less attractive than low-density UN for the contemplated space power reactor use.

Bowles, K. J.; Gluyas, R. E.

1975-01-01

95

Process for electrolytically preparing uranium metal  

DOEpatents

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.

Haas, Paul A. (Knoxville, TN)

1989-01-01

96

Influence of uranium hydride oxidation on uranium metal behaviour  

SciTech Connect

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

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

2013-07-01

97

Preparation of High Density Uranium Nitride and Uranium Carbonitride Fuel Pellets  

Microsoft Academic Search

Uranium nitride and uranium carbonitride fuel pellets were prepared for irradiation in the Japan Material Testing Reactor. The pellets are 6.9 mm in diameter and 7 mm long, and are of natural and 5% enriched uranium. Uranium nitride powder was prepared from uranium metal via hydride and higher nitride. Uranium carbide powder was prepared from uranium metal by hydriding and

Noboru Ol; Satoru HIRAYAMA; Isami TANABE; Akikazu MURAMATSU; Toshiyuki KAWADA

1972-01-01

98

Corrosion-resistant uranium  

DOEpatents

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.

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

1981-10-21

99

Uranium Transport Modeling  

SciTech Connect

Uranium contamination is prevalent at many of the U.S. DOE facilities and at several civilian sites that have supported the nuclear fuel cycle. The potential off-site mobility of uranium depends on the partitioning of uranium between aqueous and solid (soil and sediment) phases. Hexavalent U (as uranyl, UO{sub 2}{sup 2+}) is relatively mobile, forming strong complexes with ubiquitous carbonate ion which renders it appreciably soluble even under mild reducing conditions. In the presence of carbonate, partition of uranyl to ferri-hydrate and select other mineral phases is usually maximum in the near-neutral pH range {approx} 5-8. The surface complexation reaction of uranyl with iron-containing minerals has been used as one means to model subsurface migration, used in conjunction with information on the site water chemistry and hydrology. Partitioning of uranium is often studied by short-term batch 'equilibrium' or long-term soil column testing ; MCLinc has performed both of these methodologies, with selection of method depending upon the requirements of the client or regulatory authority. Speciation of uranium in soil may be determined directly by instrumental techniques (e.g., x-ray photoelectron spectroscopy, XPS; x-ray diffraction, XRD; etc.) or by inference drawn from operational estimates. Often, the technique of choice for evaluating low-level radionuclide partitioning in soils and sediments is the sequential extraction approach. This methodology applies operationally-defined chemical treatments to selectively dissolve specific classes of macro-scale soil or sediment components. These methods recognize that total soil metal inventory is of limited use in understanding bioavailability or metal mobility, and that it is useful to estimate the amount of metal present in different solid-phase forms. Despite some drawbacks, the sequential extraction method can provide a valuable tool to distinguish among trace element fractions of different solubility related to mineral phases. Four case studies are presented: Water and Soil Characterization, Subsurface Stabilization of Uranium and other Toxic Metals, Reductive Precipitation (in situ bioremediation) of Uranium, and Physical Transport of Particle-bound Uranium by Erosion.

Bostick, William D. [Materials and Chemistry Laboratory, Inc. (MCLinc), East Tennessee Technology Park, Building K-1006, 2010 Highway 58, Suite 1000, Oak Ridge, Tennessee 37830-1702 (United States)

2008-01-15

100

Corrosion-resistant uranium  

DOEpatents

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.

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

101

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

SciTech Connect

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.

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

1995-09-01

102

High loading uranium fuel plate  

DOEpatents

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.

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

1990-01-01

103

Uranium from seawater  

SciTech Connect

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.

Gregg, D.; Folkendt, M.

1982-09-21

104

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

NASA Technical Reports Server (NTRS)

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.

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

105

Chemical separation method for uranium isotopes  

Microsoft Academic Search

This patent describes a process for isotopic enrichment of uranium. The steps of this process are: (A) preparing a solution of a uranium compound and solvent characterized in that the uranium compound involves a mixture of uranium isotopes. The isotopic mixture is to be enriched and the uranium compound is further characterized in that it possesses at least one excited

S. H. Peterson; D. C. Phillips

1986-01-01

106

Method of preparation of uranium nitride  

DOEpatents

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.

Kiplinger, Jaqueline Loetsch; Thomson, Robert Kenneth James

2013-07-09

107

Controlling uranium reactivity March 18, 2008  

E-print Network

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

Meyer, Karsten

108

Method for fabricating uranium foils and uranium alloy foils  

DOEpatents

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.

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

109

Uranium prospecting method  

SciTech Connect

A technique of applying the thermoluminescence phenomenon to uranium prospecting. The thermoluminescence of specimens of quartz isolated from field samples is measured. The samples are then irradiated at several levels, and the thermoluminescence of the samples is measured at the various levels. This enables a determination of the natural radiation received by the samples the current radiation from the samples is measured with a dosimeter, and by using both shielded and unshielded dosimeters the type of radiation from the samples can be determined. Knowledge of the total natural radiation received by a sample and the current rate of radioactivity allows the determination of the present position of uranium or other radioactive source and its geological ''migration'' path.

Cabbiness, D.K.; Carel, A.B.; Leslie, W.D.

1981-05-12

110

Treatment of effluents from uranium oxide production.  

PubMed

The nuclear fuel cycle comprises a series of industrial processes which involve the production of electricity from uranium in nuclear power reactors. In Brazil the conversion of uranium hexafluoride (UF6) into uranium dioxide (UO2) takes place in Resende (RJ) at the Nuclear Fuel Factory (FCN). The process generates liquid effluents with significant concentrations of uranium, which might be treated before being discharged into the environment. This study investigates the recovery of uranium from three distinct liquid effluents: one with a high carbonate content and the other with an elevated fluoride concentration. This paper also presents a study on carbonate removal from an effluent that consists of a water-methanol solution generated during the filtration of the yellow cake (ammonium uranyl tricarbonate). The results showed that: (1) the uranium from the carbonated solution can be recovered through the ion exchange technique using the strong base anionic resin IRA 910-U, as the carbonate has been removed as CO2 after heating; (2) the most suitable technique to recover uranium from the fluoride solution is its precipitation as (NH4)2UO4F2 (ammonium fluorouranate peroxide), (3) the solution free of carbonate can be added to the fluoride solution and the uranium from the final solution can be recovered by precipitation as ammonium fluorouranate peroxide as well; (4) the carbonate from the water-methanol solution can be recovered as calcium carbonate through the addition of calcium chloride, or it can be recovered as ammonium sulphate through the addition of sulphuric acid. The ammonium sulphate product can be used as a fertilizer. PMID:21473275

Ladeira, A C Q; Gonçalves, J S; Morais, C A

2011-01-01

111

Recovery of uranium from lignites  

SciTech Connect

Uranium in raw lignite is associated with the organic matter and is readily soluble in acid (and carbonate) solutions. However, beneficiation techniques were not successful for concentrating the uranium or removing part of the reagent-consuming materials. Once the lignite was heated, the uranium became much less soluble in both acid and carbonate solutions, and complete removal of carbon was required to convert it back to a soluble form. Proper burning improves acid-leaching efficiency; that is, it reduces the reagent consumption and concentrates the uranium, thereby reducing plant size for comparable uranium throughput, and it eliminates organic fouling of leach liquors. Restrictions are necessary during burning to prevent the uranium from becoming refractory. The most encouraging results were obtained by flash-burning lignite at 1200 to 1300/sup 0/C and utilizing the released SO/sub 2/ to supplement the acid requirement. The major acid consumers were aluminum and iron.

Hurst, F.J.

1980-01-01

112

Depleted Uranium in Repositories  

SciTech Connect

For uranium to be useful in most fission nuclear reactors, it must be enriched (i.e. the concentration of the fissile isotope 235U must be increased). Therefore, depleted uranium (DU)-uranium which has less than naturally occurring concentrations of 235U-is a co-product of the enrichment process. Four to six tons of DU exist for every ton of fresh light water reactor fuel. There were 407,006 MgU 407,000 metric tons (t) of DU stored on U.S. Department of Energy (DOE) sites as of July 1993. If this DU were to be declared surplus, converted to a stable oxide form, and emplaced in a near surface disposal facility, the costs are estimated to be several billion dollars. However, the U.S. Nuclear Regulatory Commission has stated that near surface disposal of large quantities of DU tails is not appropriate. Thus, there is the possibility that disposition via disposal will be in a deep geological repository. One alternative that may significantly reduce the cost of DU disposition is to use it beneficially. In fact, DOE has begun the Beneficial Uses of DU Project to identify large scale uses of DU and to encourage its reuse. Several beneficial uses, many of which involve applications in the repository per se or in managing the wastes to go into the repository, are discussed in this report.

Haire, M.J.; Croff, A.G.

1997-12-31

113

Uranium geology of Bulgaria  

SciTech Connect

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.

Not Available

1993-02-01

114

Sputtering of uranium  

NASA Technical Reports Server (NTRS)

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.

Gregg, R.; Tombrello, T. A.

1978-01-01

115

NEWS AND INFORMATION: Depleted uranium  

Microsoft Academic Search

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

Richard Wakeford

2001-01-01

116

Uranium Critical Point Location Problem  

E-print Network

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.

Iosilevskiy, Igor

2013-01-01

117

77 FR 12880 - Uranium From Russia  

Federal Register 2010, 2011, 2012, 2013

...731-TA-539-C (Third Review)] Uranium From Russia Determination On the basis...termination of the suspended investigation on uranium from Russia would be likely to lead to...Publication 4307 (February 2012), entitled Uranium from Russia: Investigation No....

2012-03-02

118

77 FR 14837 - Bioassay at Uranium Mills  

Federal Register 2010, 2011, 2012, 2013

...COMMISSION [NRC-2012-0057] Bioassay at Uranium Mills AGENCY: Nuclear Regulatory Commission...guide (DG), DG-8051, ``Bioassay at Uranium Mills.'' This guide describes a bioassay program acceptable to the NRC staff for uranium mills and applicable portions of...

2012-03-13

119

Fungal transformations of uranium oxides.  

PubMed

The biogeochemical activities of free-living and symbiotic fungi must be acknowledged in attempts to understand uranium cycling and dispersal in the environment. Although the near-surface geochemistry of uranium is very complex and a wide variety of mineral phases is known, uranium trioxide (UO3) and triuranium octaoxide (U(3)O(8)) can be used as well characterized models in the study of biotransformations. We have used a complex methodological approach involving advanced solid state speciation and scanning electron microscopy to study the ability of saprotrophic, ericoid and ectomycorrhizal fungi to transform these model oxides. This study has revealed that fungi exhibit a high uranium oxide tolerance, and possess the ability to solubilize UO3 and U(3)O(8) and to accumulate uranium within the mycelium to over 80 mg (g dry weight)(-1) biomass. X-ray absorption spectroscopy of uranium speciation within the biomass showed that in most of the fungi the uranyl ion was coordinated to phosphate ligands, but in ectomycorrhizal fungi mixed phosphate/carboxylate coordination was observed. Abundant uranium precipitates associated with phosphorus were found in the mycelium and encrusted the hyphae. Some of the fungi caused the biomineralization of well-crystallized uranyl phosphate minerals of the meta-autunite group. This is the first experimental evidence for fungal transformations of uranium solids and the production of secondary mycogenic uranium minerals. PMID:17564604

Fomina, M; Charnock, J M; Hillier, S; Alvarez, R; Gadd, G M

2007-07-01

120

Uranium droplet core nuclear rocket  

NASA Technical Reports Server (NTRS)

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.

Anghaie, Samim

1991-01-01

121

Oxidation states of uranium in depleted uranium particles from Kuwait  

Microsoft Academic Search

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

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

2004-01-01

122

12. VIEW OF DEPLETED URANIUM INGOT AND MOLDS. DEPLETED URANIUM ...  

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

12. VIEW OF DEPLETED URANIUM INGOT AND MOLDS. DEPLETED URANIUM CASTING OPERATIONS CEASED IN 1988. (11/14/57) - Rocky Flats Plant, Non-Nuclear Production Facility, South of Cottonwood Avenue, west of Seventh Avenue & east of Building 460, Golden, Jefferson County, CO

123

Conversion of depleted uranium hexafluoride to a solid uranium compound  

DOEpatents

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.

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

2001-01-01

124

The terrestrial uranium isotope cycle  

NASA Astrophysics Data System (ADS)

Changing conditions on the Earth's surface can have a remarkable influence on the composition of its overwhelmingly more massive interior. The global distribution of uranium is a notable example. In early Earth history, the continental crust was enriched in uranium. Yet after the initial rise in atmospheric oxygen, about 2.4 billion years ago, the aqueous mobility of oxidized uranium resulted in its significant transport to the oceans and, ultimately, by means of subduction, back to the mantle. Here we explore the isotopic characteristics of this global uranium cycle. We show that the subducted flux of uranium is isotopically distinct, with high 238U/235U ratios, as a result of alteration processes at the bottom of an oxic ocean. We also find that mid-ocean-ridge basalts (MORBs) have 238U/235U ratios higher than does the bulk Earth, confirming the widespread pollution of the upper mantle with this recycled uranium. Although many ocean island basalts (OIBs) are argued to contain a recycled component, their uranium isotopic compositions do not differ from those of the bulk Earth. Because subducted uranium was probably isotopically unfractionated before full oceanic oxidation, about 600 million years ago, this observation reflects the greater antiquity of OIB sources. Elemental and isotope systematics of uranium in OIBs are strikingly consistent with previous OIB lead model ages, indicating that these mantle reservoirs formed between 2.4 and 1.8 billion years ago. In contrast, the uranium isotopic composition of MORB requires the convective stirring of recycled uranium throughout the upper mantle within the past 600 million years.

Andersen, Morten B.; Elliott, Tim; Freymuth, Heye; Sims, Kenneth W. W.; Niu, Yaoling; Kelley, Katherine A.

2015-01-01

125

The terrestrial uranium isotope cycle.  

PubMed

Changing conditions on the Earth's surface can have a remarkable influence on the composition of its overwhelmingly more massive interior. The global distribution of uranium is a notable example. In early Earth history, the continental crust was enriched in uranium. Yet after the initial rise in atmospheric oxygen, about 2.4 billion years ago, the aqueous mobility of oxidized uranium resulted in its significant transport to the oceans and, ultimately, by means of subduction, back to the mantle. Here we explore the isotopic characteristics of this global uranium cycle. We show that the subducted flux of uranium is isotopically distinct, with high (238)U/(235)U ratios, as a result of alteration processes at the bottom of an oxic ocean. We also find that mid-ocean-ridge basalts (MORBs) have (238)U/(235)U ratios higher than does the bulk Earth, confirming the widespread pollution of the upper mantle with this recycled uranium. Although many ocean island basalts (OIBs) are argued to contain a recycled component, their uranium isotopic compositions do not differ from those of the bulk Earth. Because subducted uranium was probably isotopically unfractionated before full oceanic oxidation, about 600 million years ago, this observation reflects the greater antiquity of OIB sources. Elemental and isotope systematics of uranium in OIBs are strikingly consistent with previous OIB lead model ages, indicating that these mantle reservoirs formed between 2.4 and 1.8 billion years ago. In contrast, the uranium isotopic composition of MORB requires the convective stirring of recycled uranium throughout the upper mantle within the past 600 million years. PMID:25592542

Andersen, Morten B; Elliott, Tim; Freymuth, Heye; Sims, Kenneth W W; Niu, Yaoling; Kelley, Katherine A

2015-01-15

126

Method for fluorination of uranium oxide  

DOEpatents

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.

Petit, George S. (Oak Ridge, TN)

1987-01-01

127

Solubility measurement of uranium in uranium-contaminated soils  

SciTech Connect

A short-term equilibration study involving two uranium-contaminated soils at the Fernald site was conducted as part of the In Situ Remediation Integrated Program. The goal of this study is to predict the behavior of uranium during on-site remediation of these soils. Geochemical modeling was performed on the aqueous species dissolved from these soils following the equilibration study to predict the on-site uranium leaching and transport processes. The soluble levels of total uranium, calcium, magnesium, and carbonate increased continually for the first four weeks. After the first four weeks, these components either reached a steady-state equilibrium or continued linearity throughout the study. Aluminum, potassium, and iron, reached a steady-state concentration within three days. Silica levels approximated the predicted solubility of quartz throughout the study. A much higher level of dissolved uranium was observed in the soil contaminated from spillage of uranium-laden solvents and process effluents than in the soil contaminated from settling of airborne uranium particles ejected from the nearby incinerator. The high levels observed for soluble calcium, magnesium, and bicarbonate are probably the result of magnesium and/or calcium carbonate minerals dissolving in these soils. Geochemical modeling confirms that the uranyl-carbonate complexes are the most stable and dominant in these solutions. The use of carbonate minerals on these soils for erosion control and road construction activities contributes to the leaching of uranium from contaminated soil particles. Dissolved carbonates promote uranium solubility, forming highly mobile anionic species. Mobile uranium species are contaminating the groundwater underlying these soils. The development of a site-specific remediation technology is urgently needed for the FEMP site.

Lee, S.Y.; Elless, M.; Hoffman, F.

1993-08-01

128

Microbiological control in uranium processing  

Microsoft Academic Search

A method is described of improving the recovery of UâOâ from circulating aqueous leach fluids used to extract uranium from its ores in underground uranium fields. The fields are made up of a series of injection and producing wells. The aqueous fluids are contaminated by suspended and dissolved inorganic iron compounds caused by the presence of anerobic and anerobic bacteria.

Stuebner

1987-01-01

129

URANIUM PYROPHORICITY PHENOMENA AND PREDICTION  

Microsoft Academic Search

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

Martin G. Plys; Michael Epstein; Boro Malinovic

130

Emission of Neutrons by Uranium  

Microsoft Academic Search

Fast neutrons emitted by uranium under the action of thermal neutrons were studied by using a radium-beryllium photoneutron source. The background due to the primary neutrons can be neglected since only a few of the photoneutrons are sufficiently fast to be counted. Data are obtained concerning the energy spectrum of the uranium fission neutrons by recording photographically by means of

W. H. Zinn; Leo Szilard

1939-01-01

131

Compensation of Navajo Uranium Miners  

NSDL National Science Digital Library

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.

World Information Service on Energy Uranium Project

132

Uranium in foraminiferal calcite as a recorder of seawater uranium concentrations  

Microsoft Academic Search

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

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

1994-01-01

133

Uranium in river water  

SciTech Connect

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 do not represent a significant source of U in river waters. In addition, the authors have determined dissolved U levels in forty rivers from around the world and coupled these data with previous measurements to obtain an estimate for the global flux of dissolved U to the oceans. The average concentration of U in river waters is 1.3 nmol/kg, but this value is biased by very high levels observed in the Ganges-Brahmaputra and Yellow rivers. When these river systems are excluded from the budget, the global average falls to 0.78 nmol/kg. The global riverine U flux lies in the range of 3-6 [times] 10[sup 7] mol/yr. The major uncertainty that restricts the accuracy of this estimate (and that of all other dissolved riverine fluxes) is the difficulty in obtaining representative samples from rivers which show large seasonal and annual variations in runoff and dissolved load.

Palmer, M.R. (Univ. of Bristol (United Kingdom)); Edmond, J.M. (Massachusetts Inst. of Technology, Cambridge, MA (United States))

1993-10-01

134

Variations in the uranium isotopic compositions of uranium ores from different types of uranium deposits  

NASA Astrophysics Data System (ADS)

Variations in 238U/235U and 234U/238U ratios were measured in uranium minerals from a spectrum of uranium deposit types, as well as diagenetic phosphates in uranium-rich basins and peraluminous rhyolites and associated autunite mineralisation from Macusani Meseta, Peru. Mean ?238U values of uranium minerals relative to NBL CRM 112-A are 0.02‰ for metasomatic deposits, 0.16‰ for intrusive, 0.18‰ for calcrete, 0.18‰ for volcanic, 0.29‰ for quartz-pebble conglomerate, 0.29‰ for sandstone-hosted, 0.44‰ for unconformity-type, and 0.56‰ for vein, with a total range in ?238U values from -0.30‰ to 1.52‰. Uranium mineralisation associated with igneous systems, including low-temperature calcretes that are sourced from U-rich minerals in igneous systems, have low ?238U values of ca. 0.1‰, near those of their igneous sources, whereas uranium minerals in basin-hosted deposits have higher and more variable values. High-grade unconformity-related deposits have ?238U values around 0.2‰, whereas lower grade unconformity-type deposits in the Athabasca, Kombolgie and Otish basins have higher ?238U values. The ?234U values for most samples are around 0‰, in secular equilibrium, but some samples have ?234U values much lower or higher than 0‰ associated with addition or removal of 234U during the past 2.5 Ma. These ?238U and ?234U values suggest that there are at least two different mechanisms responsible for 238U/235U and 234U/238U variations. The 234U/238U disequilibria ratios indicate recent fluid interaction with the uranium minerals and preferential migration of 234U. Fractionation between 235U and 238U is a result of nuclear-field effects with enrichment of 238U in the reduced insoluble species (mostly UO2) and 235U in oxidised mobile species as uranyl ion, UO22+, and its complexes. Therefore, isotopic fractionation effects should be reflected in 238U/235U ratios in uranium ore minerals formed either by reduction of uranium to UO2 or chemical precipitation in the form of U6+ minerals. The ?238U values of uranium ore minerals from a variety of deposits are controlled by the isotopic signature of the uranium source, the efficiency of uranium reduction in the case of UO2 systems, and the degree to which uranium was previously removed from the fluid, with less influence from temperature of ore formation and later alteration of the ore. Uranium isotopes are potentially superb tracers of redox in natural systems.

Uvarova, Yulia A.; Kyser, T. Kurt; Geagea, Majdi Lahd; Chipley, Don

2014-12-01

135

Uranium and plutonium isotopes in the atmosphere  

Microsoft Academic Search

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.

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

1983-01-01

136

Uranium Management - Preservation of a National Asset  

Microsoft Academic Search

The Uranium Management Group (UMG) was established at the Department of Energy's (DOE's) Oak Ridge Operations in 1999 as a mechanism to expedite the de-inventory of surplus uranium from the Fernald Environmental Management Project site. This successful initial venture has broadened into providing uranium material de-inventory and consolidation support to the Hanford site as well as retrieving uranium materials that

J. D. Jackson; J. C. Stroud

2002-01-01

137

31 CFR 540.309 - Natural uranium.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Natural uranium. 540.309 Section 540.309 Money...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS...General Definitions § 540.309 Natural uranium. The term natural uranium means...

2011-07-01

138

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

139

31 CFR 540.309 - Natural uranium.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Natural uranium. 540.309 Section 540.309 Money...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS...General Definitions § 540.309 Natural uranium. The term natural uranium means...

2012-07-01

140

31 CFR 540.309 - Natural uranium.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Natural uranium. 540.309 Section 540.309 Money...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS...General Definitions § 540.309 Natural uranium. The term natural uranium means...

2013-07-01

141

Uranium accumulation by Pseudomonas sp. EPS5028  

Microsoft Academic Search

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

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

1991-01-01

142

31 CFR 540.309 - Natural uranium.  

...2014-07-01 2014-07-01 false Natural uranium. 540.309 Section 540.309 Money...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS...General Definitions § 540.309 Natural uranium. The term natural uranium means...

2014-07-01

143

The Uranium Institute 24th Annual Symposium  

E-print Network

The Uranium Institute 24th Annual Symposium 8-10 September 1999: London © Uranium Institute 1999 1 the rare (0.7%) isotope of uranium, U-235, was fissionable by slow neutrons and would be burnt up in a reactor. Uranium appeared to be a scarce mineral with only three known suppliers: the Joachimstal mine

Laughlin, Robert B.

144

SHEEP MOUNTAIN URANIUM PROJECT CROOKS GAP, WYOMING  

E-print Network

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

145

31 CFR 540.309 - Natural uranium.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Natural uranium. 540.309 Section 540.309 Money...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS...General Definitions § 540.309 Natural uranium. The term natural uranium means...

2010-07-01

146

PURIFICATION OF URANIUM FROM URANIUM/MOLYBDENUM ALLOY  

SciTech Connect

The Savannah River Site will recycle a nuclear fuel comprised of 90% uranium-10% molybdenum by weight. The process flowsheet calls for dissolution of the material in nitric acid to a uranium concentration of 15-20 g/L without the formation of precipitates. The dissolution will be followed by separation of uranium from molybdenum using solvent extraction with 7.5% tributylphosphate in n-paraffin. Testing with the fuel validated dissolution and solubility data reported in the literature. Batch distribution coefficient measurements were performed for the extraction, strip and wash stages with particular focus on the distribution of molybdenum.

Pierce, R; Ann Visser, A; James Laurinat, J

2007-10-15

147

The End of Cheap Uranium  

E-print Network

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.

Michael Dittmar

2011-06-21

148

Determination of uranium in zircon  

USGS Publications Warehouse

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.

Cuttitta, F.; Daniels, G.J.

1959-01-01

149

Measurement of uranium enrichment for gaseous uranium at low pressure  

NASA Astrophysics Data System (ADS)

X-ray fluorescence determines the amount of total uranium present in gaseous UF6 inside cascade header pipes of a uranium centrifuge enrichment facility. A highly collimated source, highly collimated detctor, and a very rigid, reproducible geometry are required. Two measurements of the 185.7 keV gamma ray from U-235 using two collimators determine the amount of U-235 present only in the gas phase. The ratio of the gas only U235 signal to the total uranium gas only signal is directly proportional to the enrichment of the process UF6 gas. This measurement technique is independent of the deposit that forms on a surface in contact with UF6. This measurement technique is independent of the pressure of the gaseous UF6. This technique has the required sensitivity to determine whether the process gas is of uranium enrichment less than or equal to 20% or 20%.

Close, D. A.; Pratt, J. C.; Atwater, H. F.; Malanify, J. J.; Nixon, K. V.; Speir, L. G.

150

Measurement of uranium enrichment for gaseous uranium at low pressure  

Microsoft Academic Search

X-ray fluorescence determines the amount of total uranium present in gaseous UF6 inside cascade header pipes of a uranium centrifuge enrichment facility. A highly collimated source, highly collimated detctor, and a very rigid, reproducible geometry are required. Two measurements of the 185.7 keV gamma ray from U-235 using two collimators determine the amount of U-235 present only in the gas

D. A. Close; J. C. Pratt; H. F. Atwater; J. J. Malanify; K. V. Nixon; L. G. Speir

1985-01-01

151

Uranium hexafluoride bibliography  

SciTech Connect

This bibliography is a compilation of reports written about the transportation, handling, safety, and processing of uranium hexafluoride. An on-line literature search was executed using the DOE Energy files and the Nuclear Science Abstracts file to identify pertinent reports. The DOE Energy files contain unclassified information that is processed at the Office of Scientific and Technical Information of the US Department of Energy. The reports selected from these files were published between 1974 and 1983. Nuclear Science Abstracts contains unclassified international nuclear science and technology literature published from 1948 to 1976. In addition, scientific and technical reports published by the US Atomic Energy Commission and the US Energy Research and Development Administration, as well as those published by other agencies, universities, and industrial and research organizations, are included in the Nuclear Science Abstracts file. An alphabetical listing of the acronyms used to denote the corporate sponsors follows the bibliography.

Burnham, S.L.

1988-01-01

152

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.

153

Laser induced phosphorescence uranium analysis  

DOEpatents

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.

Bushaw, B.A.

1983-06-10

154

Laser induced phosphorescence uranium analysis  

DOEpatents

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.

Bushaw, Bruce A. (Kennewick, WA)

1986-01-01

155

Uranium and Radiation Education Outreach  

NSDL National Science Digital Library

This is an educational and public program designed to increase awareness of uranium health effects and environmental issues for students and community members that are impacted by uranium mining on the Navajo Nation. The site contains lesson plans, teaching resources and information about problem-based learning. There is also a paper on bridging indigenous and traditional scientific approaches as well as many useful links to additional resources.

Northern Arizona Institute - Institute for Tribal Environmental Professionals

156

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

SciTech Connect

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

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

2007-07-01

157

Rescuing a Treasure Uranium-233  

SciTech Connect

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.

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

158

Beneficial Uses of Depleted Uranium  

SciTech Connect

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

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

1997-08-01

159

Microbial accumulation of uranium, radium, and cesium  

SciTech Connect

Diverse microbial species varied considerably in their ability to accumulate uranium, cesium, and radium. Mechanistic differences in uranium uptake by Saccharomyces cerevisiae and Pseudomonas aeruginosa were indicated. S. serevisiae exhibited a slow (hours) surface accumulation of uranium which was subject to environmental factors, while P. aeruginosa accumulated uranium rapidly (minutes) as dense intracellular deposits and did not appear to be affected by environmental parameters. Metabolism was not required for uranium uptake by either organism. Cesium and radium were concentrated to a considerably lesser extent than uranium by the several species tested.

Strandberg, G.W.; Shumate, S.E. II; Parrott, J.R. Jr.; North, S.E.

1981-05-01

160

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

E-print Network

/dehydriding process. The size distribution and morphology of the uranium powder produced by this method were determined by digital optical microscopy. Once the characteristics of the source uranium powder were known, uranium and uranium-zirconium pellets were pressed...

Helmreich, Grant

2012-02-14

161

Atomistic properties of ? uranium.  

PubMed

The properties of the body-centered cubic ? 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 (?) 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 ? 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 calculation of ? U properties above 0 K with interatomic potentials. PMID:22293061

Beeler, Benjamin; Deo, Chaitanya; Baskes, Michael; Okuniewski, Maria

2012-02-22

162

Uranium reference materials  

SciTech Connect

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.

Donivan, S.; Chessmore, R.

1987-07-01

163

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

E-print Network

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

Fayek, Mostafa

164

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

E-print Network

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

Meyer, Karsten

165

Reducing emissions from uranium dissolving  

SciTech Connect

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.

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

1992-10-01

166

Reducing emissions from uranium dissolving  

SciTech Connect

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.

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

1992-10-01

167

Inherently safe in situ uranium recovery  

DOEpatents

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

Krumhansl, James L; Brady, Patrick V

2014-04-29

168

Innovative Elution Processes for Recovering Uranium from Seawater  

SciTech Connect

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

Wai, Chien; Tian, Guoxin; Janke, Christopher

2014-05-29

169

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

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.

Mac Donald, Philip Elsworth

2002-09-01

170

Statistical data of the uranium industry  

SciTech Connect

Data are presented on US uranium reserves, potential resources, exploration, mining, drilling, milling, and other activities of the uranium industry through 1980. The compendium reflects the basic programs of the Grand Junction Office. Statistics are based primarily on information provided by the uranium exploration, mining, and milling companies. Data on commercial U/sub 3/O/sub 8/ sales and purchases are included. Data on non-US uranium production and resources are presented in the appendix. (DMC)

none,

1981-01-01

171

Y-12 Uranium Exposure Study  

SciTech Connect

Following the recent restart of operations at the Y-12 Plant, the Radiological Control Organization (RCO) observed that the enriched uranium exposures appeared to involve insoluble rather than soluble uranium that presumably characterized most earlier Y-12 operations. These observations necessitated changes in the bioassay program, particularly the need for routine fecal sampling. In addition, it was not reasonable to interpret the bioassay data using metabolic parameter values established during earlier Y-12 operations. Thus, the recent urinary and fecal bioassay data were interpreted using the default guidance in Publication 54 of the International Commission on Radiological Protection (ICRP); that is, inhalation of Class Y uranium with an activity median aerodynamic diameter (AMAD) of 1 {micro}m. Faced with apparently new workplace conditions, these actions were appropriate and ensured a cautionary approach to worker protection. As additional bioassay data were accumulated, it became apparent that the data were not consistent with Publication 54. Therefore, this study was undertaken to examine the situation.

Eckerman, K.F.; Kerr, G.D.

1999-08-05

172

Scrap uranium recycling via electron beam melting  

Microsoft Academic Search

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

McKoon

1993-01-01

173

Spectrophotometric determination of uranium using dibenzoylmethane  

Microsoft Academic Search

A procedure for the spectrophotometric determination of uranium has been developed in support of minerals research being conducted by the Bureau of Mines. Uranium is separated from the sample by tributylphosphate extraction from acid solution containing added aluminum nitrate and (ethylene dinitrilo)-tetraacetic acid solutions. The colored uranium-dibenzoylmethane complex is developed in the organic phase by adding an ethanol solution of

M. M. Jones; J. S. MacDuff; A. B. Whitehead

1980-01-01

174

Renal Effects of Uranium in Drinking Water  

Microsoft Academic Search

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.

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

2002-01-01

175

Medical effects of internal contamination with uranium.  

PubMed

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

Durakovi?, A

1999-03-01

176

Phosphate Bariers for Immobilization of Uranium Plumes  

SciTech Connect

Uranium contamination of the subsurface has remained a persistent problem plaguing remedial design at sites across the U.S. that were involved with production, handling, storage, milling, and reprocessing of uranium for both civilian and defense related purposes. Remediation efforts to date have relied upon excavation, pump-and-treat, or passive remediation barriers (PRB's) to remove or attenuate uranium mobility.

Peter C. Burns

2007-01-26

177

Ion exchange enrichment of uranium isotopes  

Microsoft Academic Search

A process for the enrichment of one isotope in a mixture of uranium isotopes by passing a solution of the mixture in a solvent through an anion exchanger thereby forming on the anion exchanger a boundary (A) between a uranium adsorption zone and an adjacent reducing agent zone and\\/or a boundary (B) between a uranium adsorption zone and an adjacent

T. Miyake; H. Onitsuka; K. Takeda

1983-01-01

178

Safe Operating Procedure SAFETY PROTOCOL: URANIUM  

E-print Network

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

Farritor, Shane

179

Recovery of uranium by immobilized microorganisms  

Microsoft Academic Search

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

Akira Nakajima; Takao Horikoshi; Takashi Sakaguchi

1982-01-01

180

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

181

URANIUM MILL TAILINGS RADON FLUX CALCULATIONS  

E-print Network

URANIUM MILL TAILINGS RADON FLUX CALCULATIONS PIÃ?ON 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

182

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

183

Interactions of uranium with polyphosphate.  

PubMed

Inorganic polyphosphates (PolyP) are simple linear phosphate (PO(4)(3-)) 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 (1400-1900Da) 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-HPO(4) complex revealed that an insoluble uranyl phosphate species was formed below pH 6; at higher pH (> or = 8) 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 (< or = 6) 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 PO(4) and PolyP are dependent upon pH. PMID:17673274

Vazquez, Gustavo J; Dodge, Cleveland J; Francis, Arokiasamy J

2007-12-01

184

Microbiological control in uranium processing  

SciTech Connect

A method is described of improving the recovery of U/sub 3/O/sub 8/ from circulating aqueous leach fluids used to extract uranium from its ores in underground uranium fields. The fields are made up of a series of injection and producing wells. The aqueous fluids are contaminated by suspended and dissolved inorganic iron compounds caused by the presence of anerobic and anerobic bacteria. The method comprises treating such aqueous leach fluids with at least 0.1 ppm of a mixture of 75% of 5-chloro-2-methyl-4-isothiazolin-3-one and 25% 2-methyl-4-isothiazolin-3-one.

Stuebner, T.L.

1987-04-07

185

Uranium mill tailings and radon  

SciTech Connect

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

Hanchey, L A

1981-01-01

186

Distribution of uranium in rats implanted with depleted uranium pellets  

Microsoft Academic Search

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

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

1999-01-01

187

NUSIMEP-7: uranium isotope amount ratios in uranium particles.  

PubMed

The Institute for Reference Materials and Measurements (IRMM) has extensive experience in the development of isotopic reference materials and the organization of interlaboratory comparisons (ILC) for nuclear measurements in compliance with the respective international guidelines (ISO Guide 34:2009 and ISO/IEC 17043:2010). The IRMM Nuclear Signatures Interlaboratory Measurement Evaluation Program (NUSIMEP) is an external quality control program with the objective of providing materials for measurements of trace amounts of nuclear materials in environmental matrices. Measurements of the isotopic ratios of the elements uranium and plutonium in small amounts, typical of those found in environmental samples, are required for nuclear safeguards and security, for the control of environmental contamination and for the detection of nuclear proliferation. The measurement results of participants in NUSIMEP are evaluated according to international guidelines in comparison to independent external certified reference values with demonstrated metrological traceability and uncertainty. NUSIMEP-7 focused on measurements of uranium isotope amount ratios in uranium particles aiming to support European Safeguards Directorate General for Energy (DG ENER), the International Atomic Energy Agency's (IAEA) network of analytical laboratories for environmental sampling (NWAL) and laboratories in the field of particle analysis. Each participant was provided two certified test samples: one with single and one with double isotopic enrichment. These NUSIMEP test samples were prepared by controlled hydrolysis of certified uranium hexafluoride in a specially designed aerosol deposition chamber at IRMM. Laboratories participating in NUSIMEP-7 received the test samples of uranium particles on two graphite disks with undisclosed isotopic ratio values n((234)U)/n((238)U), n((235)U)/n((238)U) and n((236)U)/n((238)U). The uranium isotope ratios had to be measured using their routine analytical procedures. Measurement of the major ratio n((235)U)/n((238)U) was obligatory; measurement of the minor ratios n((234)U)/n((238)U) and n((236)U)/n((238)U) was optional. Of the twenty-four institutes that registered for NUSIMEP-7, 17 have reported their results achieved by different analytical methods. The results of NUSIMEP-7 confirm the capability of laboratories in measuring n((234)U)/n((238)U), n((235)U)/n((238)U) and n((236)U)/n((238)U) in uranium particles of the size below 1 ?m diameter. Furthermore, they underpin the recent advances in instrumental techniques in the field of particle analysis. In addition, feedback from the measurement communities from nuclear safeguards, nuclear security and earth sciences was collected in view of identifying future needs for NUSIMEP interlaboratory comparisons. PMID:23548475

Truyens, J; Stefaniak, E A; Aregbe, Y

2013-11-01

188

Interactions of uranium atom with tetraketone complexes  

NASA Astrophysics Data System (ADS)

Using first principles theory based on density functional formulation we have studied the interactions of uranium atom with tetraketone complexes used for all-uranium redox flow battery. The geometry and electronic structures are studied in detail. We found that uranium atom interacts strongly with tetraketone complexes, the interaction energy is more than 7.0 eV, and uranium atom acts as an electron acceptor with about 0.6 electrons transferred from tetraketone complexes, while uranium atom carries the magnetic moment of 2 ?B.

Sun, Q.; Wang, Q.; Shiokawa, Y.; Kawazoe, Y.

2005-11-01

189

Removal of uranium from aqueous HF solutions  

DOEpatents

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

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

1980-01-01

190

Process for alloying uranium and niobium  

DOEpatents

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.

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

191

Oxidation states of uranium in depleted uranium particles from Kuwait.  

PubMed

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

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

2005-01-01

192

Aqueous dissolution rates of uranium oxides  

SciTech Connect

An understanding of the long-term dissolution of waste forms in groundwater is required for the safe disposal of high level nuclear waste in an underground repository. The main routes by which radionuclides could be released from a geological repository are the dissolution and transport processes in groundwater flow. Because uranium dioxide is the primary constituent of spent nuclear fuel, the dissolution of its matrix in spent fuel is considered the rate-limiting step for release of radioactive fission products. The purpose of our work has been to measure the intrinsic dissolution rates of uranium oxides under a variety of well-controlled conditions that are relevant to a repository and allow for modeling. The intermediate oxide phase U{sub 3}O{sub 8}, triuranium octaoxide, is quite stable and known to be present in oxidized spent fuel. The trioxide, UO{sub 3}, has been shown to exist in drip tests on spent fuel. Here we compare the results of essentially identical dissolution experiments performed on depleted U{sub 3}O{sub 8} and dehyrated schoepite or uranium trioxide monohydrate (UO{sub 3}{center_dot}H{sub 2}O). These are compared with earlier work on spent fuel and UO{sub 2} under similar conditions.

Steward, S. A.; Mones, E. T.

1994-10-01

193

Uranium 2005 resources, production and demand  

E-print Network

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...

Organisation for Economic Cooperation and Development. Paris

2006-01-01

194

Soil Sampling Near Uranium Mine  

USGS Multimedia Gallery

USGS Scientists Sarah Davis, Taylor Mills, and David Naftz collect soil samples near the Pinenut uranium mine. Mine features visible in the background include the gray ore stockpile at the far left, the head frame used to access the underground mine workings at mid left, and the detention pond conta...

195

Civil use of depleted uranium  

Microsoft Academic Search

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

Maria Betti

2003-01-01

196

Enriched uranium recovery flowsheet improvements  

SciTech Connect

Savannah River uses 7.5% TBP to recover and purify enriched uranium. Adequate decontamination from fission products is necessary to reduce personnel exposure and to ensure that the enriched uranium product meets specifications. Initial decontamination of the enriched uranium from the fission products is carried out in the 1A bank, 16 stages of mixer-settlers. Separation of the enriched uranium from the fission product, /sup 95/Zr, has been adequate, but excessive solvent degradation caused by the long phase contact times in the mixer-settlers has limited the /sup 95/Zr decontamination factor (DF). An experimental program is investigating the replacement of the current 1A bank with either centrifugal contactors or a combination of centrifugal contactors and mixer-settlers. Experimental work completed has compared laboratory-scale centrifugal contactors and mixer-settlers for /sup 95/Zr removal efficiencies. Feed solutions spiked with actual plant solutions were used. The /sup 95/Zr DF was significantly better in the mixer-settlers than in the centrifugal contactors. As a result of this experimental study, a hybrid equipment flowsheet has been proposed for plant use. The hybrid equipment flowsheet combines the advantages of both types of solvent extraction equipment. Centrifugal contactors would be utilized in the extraction and initial scrub sections, followed by additional scrub stages of mixer-settlers.

Holt, D L

1986-01-01

197

Discordant Uranium-Lead Ages  

Microsoft Academic Search

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

G. W. WETHERILL

1963-01-01

198

Magnesium bicarbonate as an in situ uranium lixiviant  

SciTech Connect

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.

Sibert, J.W.

1984-09-25

199

DEVELOPMENT OF CERAMIC COATINGS FOR URANIUM AND THORIUM  

Microsoft Academic Search

Full-size Hanford uranium slugs have been successfully coated with ; vitreous porcelain enamels with consistently good results. Uranium-1.5 at. % ; silicon alloy and uranium-0.5 at. % chromium alloy disks and slugs were amenable ; to coating by the same techniques used with unalloyed uranium. Glasses of ; beryllium fluoride base were developed as low-temperature uranium coatings, but ; these

G. L. Ploetz; C. W. Krystyniak

1956-01-01

200

Inherently safe in situ uranium recovery.  

SciTech Connect

Expansion of uranium mining in the United States is a concern to some environmental groups and sovereign Native American Nations. An approach which may alleviate some problems is to develop inherently safe in situ uranium recovery ('ISR') technologies. Current ISR technology relies on chemical extraction of trace levels of uranium from aquifers that, once mined, can still contain dissolved uranium and other trace metals that are a health concern. Existing ISR operations are few in number; however, high uranium prices are driving the industry to consider expanding operations nation-wide. Environmental concerns and enforcement of the new 30 ppb uranium drinking water standard may make opening new mining operations more difficult and costly. Here we propose a technological fix: the development of inherently safe in situ recovery (ISISR) methods. The four central features of an ISISR approach are: (1) New 'green' leachants that break down predictably in the subsurface, leaving uranium, and associated trace metals, in an immobile form; (2) Post-leachant uranium/metals-immobilizing washes that provide a backup decontamination process; (3) An optimized well-field design that increases uranium recovery efficiency and minimizes excursions of contaminated water; and (4) A combined hydrologic/geochemical protocol for designing low-cost post-extraction long-term monitoring. ISISR would bring larger amounts of uranium to the surface, leave fewer toxic metals in the aquifer, and cost less to monitor safely - thus providing a 'win-win-win' solution to all stakeholders.

Krumhansl, James Lee; Beauheim, Richard Louis; Brady, Patrick Vane; Arnold, Bill Walter; Kanney, Joseph F.; McKenna, Sean Andrew

2009-05-01

201

Reports on investigations of uranium anomalies. National Uranium Resource Evaluation  

SciTech Connect

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

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

1982-10-01

202

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

E-print Network

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. ...

Matthews, Isaac A

2010-01-01

203

Measurement of Trace Uranium Isotopes  

SciTech Connect

The extent to which thermal ionization mass spectrometry (TIMS) can measure trace quantities of 233U and 236U in the presence of a huge excess of natural uranium is evaluated. This is an important nuclear non-proliferation measurement. Four ion production methods were evaluated with three mass spectrometer combinations. The most favorable combinations are not limited by abundance sensitivity; rather, the limitations are the ability to generate a uranium ion beam of sufficient intensity to obtain the required number of counts on the minor isotopes in relationship to detector background. The most favorable situations can measure isotope ratios in the range of E10 if sufficient sample intensity is available. These are the triple sector mass spectrometer with porous ion emitters (PIE) and the single sector mass spectrometer with energy filtering.

Matthew G. Watrous; James E. Delmore

2011-05-01

204

Uranium Metal Analysis via Selective Dissolution  

SciTech Connect

Uranium metal, which is present in sludge held in the Hanford Site K West Basin, can create hazardous hydrogen atmospheres during sludge handling, immobilization, or subsequent transport and storage operations by its oxidation/corrosion in water. A thorough knowledge of the uranium metal concentration in sludge therefore is essential to successful sludge management and waste process design. The goal of this work was to establish a rapid routine analytical method to determine uranium metal concentrations as low as 0.03 wt% in sludge even in the presence of up to 1000-fold higher total uranium concentrations (i.e., up to 30 wt% and more uranium) for samples to be taken during the upcoming sludge characterization campaign and in future analyses for sludge handling and processing. This report describes the experiments and results obtained in developing the selective dissolution technique to determine uranium metal concentration in K Basin sludge.

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

2008-09-10

205

Uranium 2009 resources, production and demand  

E-print Network

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...

Organisation for Economic Cooperation and Development. Paris

2010-01-01

206

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

E-print Network

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

Boyer, Edmond

207

Luminescence of powdered uranium glasses  

NASA Technical Reports Server (NTRS)

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.

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

1974-01-01

208

Review of uranium bioassay techniques  

SciTech Connect

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

Bogard, J.S.

1996-04-01

209

Material property correlations for uranium mononitride  

E-print Network

CHAPTER I INTRODUCTION Objectives Uranium nitride (VN) is currently under consideration for application as a nuclear fuel for both the SP-100 and Multimegawatt space reactor programs. The attractiveness of UN as a space nuclear fuel lies in its high... conductivity, high uranium density, stable irradiation behavior and compatibility with liquid metal coolants and refractory metal structural materials all combine to make uranium mononitride (UN) a very attractive nuclear fuel for use in high temperature...

Hayes, Steven Lowe

1989-01-01

210

Determination of uranium in natural waters  

USGS Publications Warehouse

The fluorophotometric determination of uranium was studied to develop a procedure applicable to the routine analysis of waters. Three grams of the high carbonate flux are used in a dilution procedure with spiking. Because of the comparatively high reflectivity of this large disk and the low uranium concentration, a correction for nonquenched light is required. A formula is developed to compensate for the effect, an electrical fusion device is described, and the problem of fixing uranium in waters is discussed.

Thatcher, L.L.; Barker, F.B.

1957-01-01

211

Uranium mill tailings quarterly report, January-March 1982  

SciTech Connect

Progress is reported on: radon barrier systems for uranium mill tailings; liner evaluation for uranium mill tailings; revegetation/rock cover for stabilization of inactive U-tailings sites; and application of long-term chemical biobarriers for uranium tailings.

Latkovich, J.M. (comp.)

1982-05-01

212

31 CFR 540.306 - Highly Enriched Uranium (HEU).  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Highly Enriched Uranium (HEU). 540.306 Section 540...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS...Definitions § 540.306 Highly Enriched Uranium (HEU). The term highly enriched...

2012-07-01

213

31 CFR 540.308 - Low Enriched Uranium (LEU).  

Code of Federal Regulations, 2010 CFR

... 2010-07-01 false Low Enriched Uranium (LEU). 540.308 Section 540...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS...Definitions § 540.308 Low Enriched Uranium (LEU). The term low enriched...

2010-07-01

214

Geobacter uraniireducens sp. nov., isolated from subsurface sediment undergoing uranium  

E-print Network

Geobacter uraniireducens sp. nov., isolated from subsurface sediment undergoing uranium with acetate oxidation, was isolated from subsurface sediment undergoing uranium bioremediation. The 16S r was to recover an environmentally relevant Geobacter strain from subsurface sediments undergoing in situ uranium

Lovley, Derek

215

31 CFR 540.306 - Highly Enriched Uranium (HEU).  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Highly Enriched Uranium (HEU). 540.306 Section 540...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS...Definitions § 540.306 Highly Enriched Uranium (HEU). The term highly enriched...

2010-07-01

216

31 CFR 540.306 - Highly Enriched Uranium (HEU).  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Highly Enriched Uranium (HEU). 540.306 Section 540...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS...Definitions § 540.306 Highly Enriched Uranium (HEU). The term highly enriched...

2011-07-01

217

31 CFR 540.308 - Low Enriched Uranium (LEU).  

Code of Federal Regulations, 2012 CFR

... 2012-07-01 false Low Enriched Uranium (LEU). 540.308 Section 540...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS...Definitions § 540.308 Low Enriched Uranium (LEU). The term low enriched...

2012-07-01

218

31 CFR 540.308 - Low Enriched Uranium (LEU).  

Code of Federal Regulations, 2013 CFR

... 2013-07-01 false Low Enriched Uranium (LEU). 540.308 Section 540...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS...Definitions § 540.308 Low Enriched Uranium (LEU). The term low enriched...

2013-07-01

219

31 CFR 540.306 - Highly Enriched Uranium (HEU).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Highly Enriched Uranium (HEU). 540.306 Section 540...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS...Definitions § 540.306 Highly Enriched Uranium (HEU). The term highly enriched...

2013-07-01

220

31 CFR 540.308 - Low Enriched Uranium (LEU).  

... 2014-07-01 false Low Enriched Uranium (LEU). 540.308 Section 540...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS...Definitions § 540.308 Low Enriched Uranium (LEU). The term low enriched...

2014-07-01

221

31 CFR 540.308 - Low Enriched Uranium (LEU).  

Code of Federal Regulations, 2011 CFR

... 2011-07-01 false Low Enriched Uranium (LEU). 540.308 Section 540...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS...Definitions § 540.308 Low Enriched Uranium (LEU). The term low enriched...

2011-07-01

222

31 CFR 540.306 - Highly Enriched Uranium (HEU).  

...2014-07-01 false Highly Enriched Uranium (HEU). 540.306 Section 540...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS...Definitions § 540.306 Highly Enriched Uranium (HEU). The term highly enriched...

2014-07-01

223

Uranium metal reactions with hydrogen and water vapour and the reactivity of the uranium hydride produced  

SciTech Connect

Within the nuclear industry, metallic uranium has been used as a fuel. If this metal is stored in a hydrogen rich environment then the uranium metal can react with the hydrogen to form uranium hydride which can be pyrophoric when exposed to air. The UK National Nuclear Laboratory has been carrying out a programme of research for Sellafield Limited to investigate the conditions required for the formation and persistence of uranium hydride and the reactivity of the material formed. The experimental results presented here have described new results characterising uranium hydride formed from bulk uranium at 50 and 160 C. degrees and measurements of the hydrolysis kinetics of these materials in liquid water. It has been shown that there is an increase in the proportion of alpha-uranium hydride in material formed at lower temperatures and that there is an increase in the rate of reaction with water of uranium hydride formed at lower temperatures. This may at least in part be attributable to a difference in the reaction rate between alpha and beta-uranium hydride. A striking observation is the strong dependence of the hydrolysis reaction rate on the temperature of preparation of the uranium hydride. For example, the reaction rate of uranium hydride prepared at 50 C. degrees was over ten times higher than that prepared at 160 C. degrees at 20% extent of reaction. The decrease in reaction rate with the extent of reaction also depended on the temperature of uranium hydride preparation.

Godfrey, H. [National Nuclear Laboratory, Workington Laboratory, Havelock Road, Derwent Howe, Cumbria, CA14 3YQ (United Kingdom); Broan, C.; Goddard, D.; Hodge, N.; Woodhouse, G. [National Nuclear Laboratory, Preston Laboratory, Springfields, Salwick, Preston, Lancashire, PR4 0XJ (United Kingdom); Diggle, A. [Sellafield Limited, Sellafield, Seascale, Cumbria, CA20 1PG (United Kingdom); Orr, R. [National Nuclear Laboratory, Central Laboratory, Sellafield, Seascale, Cumbria, CA20 1PG (United Kingdom)

2013-07-01

224

A luminescence line-narrowing spectroscopic study of the uranium(VI) interaction with cementitious materials and titanium dioxide.  

PubMed

Non-selective luminescence spectroscopy and luminescence line-narrowing spectroscopy were used to study the retention of UO2(2+) on titanium dioxide (TiO2), synthetic calcium silicate hydrate (C-S-H) phases and hardened cement paste (HCP). Non-selective luminescence spectra showed strong inhomogeneous line broadening resulting from a strongly disordered UO2(2+) bonding environment. This problem was largely overcome by using luminescence line-narrowing spectroscopy. This technique allowed unambiguous identification of three different types of UO2(2+) sorbed species on C-S-H phases and HCP. Comparison with spectra of UO2(2+) sorbed onto TiO2 further allowed these species to be assigned to a surface complex, an incorporated species and an uranate-like surface precipitate. This information provides the basis for mechanistic models describing the UO2(2+) sorption onto C-S-H phases and HCP and the assessment of the mobility of this radionuclide in a deep geological repository for low and intermediate level radioactive waste (L/ILW) as this kind of waste is often solidified with cement prior to storage. PMID:25407092

Tits, Jan; Walther, Clemens; Stumpf, Thorsten; Macé, Nathalie; Wieland, Erich

2015-01-21

225

Chemistry of uranium in aluminophosphate glasses  

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

226

Colorimetric detection of uranium in water  

DOEpatents

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.

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

2012-03-13

227

77 FR 33782 - License Amendment To Construct and Operate New In Situ Leach Uranium Recovery Facility; Uranium...  

Federal Register 2010, 2011, 2012, 2013

...Amendment To Construct and Operate New In Situ Leach Uranium Recovery Facility; Uranium One Americas; Ludeman AGENCY: Nuclear Regulatory...referenced. The Ludeman facility In Situ Leach Uranium Recovery Project License Amendment Request is...

2012-06-07

228

Relative probabilities of the uranium isotopes for thorium x-ray emission and fluorescence of uranium x-rays  

Microsoft Academic Search

Both thorium x-rays from decaying uranium isotopes and self-fluoresced uranium x-rays are prominent in high-resolution gamma-ray spectra of uranium-bearing materials. Useful application of the information carried by those x-rays has been curtailed because the probabilities of the uranium isotopes for thorium x-ray emission and for uranium x-ray fluorescence have not been known. By analyzing enrichment-meter geometry spectra from uranium oxide

1991-01-01

229

Microbial uptake of uranium, cesium, and radium  

SciTech Connect

The ability of diverse microbial species to concentrate uranium, cesium, and radium was examined. Saccharomyces cerevisiae, Pseudomonas aeruginosa, and a mixed culture of denitrifying bacteria accumulated uranium to 10 to 15% of the dry cell weight. Only a fraction of the cells in a given population had visible uranium deposits in electron micrographs. While metabolism was not required for uranium uptake, mechanistic differences in the metal uptake process were indicated. Uranium accumulated slowly (hours) on the surface of S. cerevisiae and was subject to environmental factors (i.e., temperature, pH, interfering cations and anions). In contrast, P. aeruginosa and the mixed culture of denitrifying bacteria accumulated uranium rapidly (minutes) as dense, apparently random, intracellular deposits. This very rapid accumulation has prevented us from determining whether the uptake rate during the transient between the initial and equilibrium distribution of uranium is affected by environmental conditions. However, the final equilibrium distributions are not affected by those conditions which affect uptake by S. cerevisiae. Cesium and radium were concentrated to a considerably lesser extent than uranium by the several microbial species tested. The potential utility of microorganisms for the removal and concentration of these metals from nuclear processing wastes and several bioreactor designs for contacting microorganisms with contaminated waste streams will be discussed.

Strandberg, G.W.; Shumate, S.E. II; Parrott, J.R. Jr.; McWhirter, D.A.

1980-01-01

230

THE SPECTROPHOTOMETRIC DETERMINATION OF URANIUM WITH DIBENZOYLMETHANE  

Microsoft Academic Search

Description is given of a simple direct spectrophotometric determination ; of uranium with dibenzoylmethane in combination with tributyl phosphate, which is ; selected as the extractant of uranium because of its popularity. The procedure ; was applied to the determination of U in U ores and in monazite. One advantage ; of the method is that change in acidity does

Yoshimi Umezaki

1963-01-01

231

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...

232

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...

233

Experimental leaching of uranium from tuffaceous rocks  

Microsoft Academic Search

The premise to be tested in this work is that felsic volcanic rocks particularly ash-flow tuffs, can serve as source rocks for certain uranium deposits. The applicability of this idea to several geologic environments is investigated. A genetic model is developed dealing with the behavior of uranium during and subsequent to ash-flow tuff deposition. It is based upon previously described

P. C. Goodell; R. C. Trentham

1980-01-01

234

Dynamic Properties of Shock Loaded Uranium Foils  

NASA Astrophysics Data System (ADS)

A series of spall experiments have been completed with thin depleted uranium targets. The samples were nominally 0.1 mm thick. The first set of uranium spall targets were rolled to final thickness from low purity uranium. Samples for the second set were cut and ground to their final thickness from high purity (electro-refined) cast uranium. The impactors for these experiments were laser-launched 0.05 mm thick copper flyers, which were 3 mm in diameter. Laser energies were varied to yield a range of flyer impact velocities. This resulted in varying degrees of damage to the uranium spall targets, from deformation to complete spall or separation at higher velocities. Dynamic measurements of the uranium targets free surface velocity were obtained with dual velocity interferometers. Uranium targets were recovered and sectioned after testing. Free surface velocity profiles and spall strengths (estimated from the magnitude of the pull-back signals), are discussed and compared with the micro-structural evidence of spall from the sectioned uranium targets.

Robbins, David; Alexander, David; Hanrahan, Robert; Kelly, Ann; Snow, Ronny; Stahl, David; Sheffield, Stephen; Gehr, Russell; Rupp, Ted

2001-06-01

235

Uranium Dispersion and Dosimetry (UDAD) Code  

Microsoft Academic Search

The Uranium Dispersion and Dosimetry (UDAD) Code provides estimates of potential radiation exposure to individuals and to the general population in the vicinity of a uranium processing facility. The UDAD Code incorporates the radiation dose from the airborne release of radioactive materials, and includes dosimetry of inhalation, ingestion, and external exposures. The removal of raioactive particles from a contaminated area

M. H. Momeni; Y. Yuan; A. J. Zielen

1979-01-01

236

Modeled atmospheric radon concentrations from uranium mines  

Microsoft Academic Search

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

Droppo

1985-01-01

237

Uranium incorporation into amorphous silica.  

PubMed

High concentrations of uranium are commonly observed in naturally occurring amorphous silica (including opal) deposits, suggesting that incorporation of U into amorphous silica may represent a natural attenuation mechanism and promising strategy for U remediation. However, the stability of uranium in opaline silicates, determined in part by the binding mechanism for U, is an important factor in its long-term fate. U may bind directly to the opaline silicate matrix, or to materials such as iron (hydr)oxides that are subsequently occluded within the opal. Here, we examine the coordination environment of U within opaline silica to elucidate incorporation mechanisms. Precipitates (with and without ferrihydrite inclusions) were synthesized from U-bearing sodium metasilicate solutions, buffered at pH ? 5.6. Natural and synthetic solids were analyzed with X-ray absorption spectroscopy and a suite of other techniques. In synthetic amorphous silica, U was coordinated by silicate in a double corner-sharing coordination geometry (Si at ? 3.8-3.9 Å) and a small amount of uranyl and silicate in a bidentate, mononuclear (edge-sharing) coordination (Si at ? 3.1-3.2 Å, U at ? 3.8-3.9 Å). In iron-bearing synthetic solids, U was adsorbed to iron (hydr)oxide, but the coordination environment also contained silicate in both edge-sharing and corner-sharing coordination. Uranium local coordination in synthetic solids is similar to that of natural U-bearing opals that retain U for millions of years. The stability and extent of U incorporation into opaline and amorphous silica represents a long-term repository for U that may provide an alternative strategy for remediation of U contamination. PMID:24984107

Massey, Michael S; Lezama-Pacheco, Juan S; Nelson, Joey M; Fendorf, Scott; Maher, Kate

2014-08-01

238

Multiphoton ionization of uranium hexafluoride  

NASA Astrophysics Data System (ADS)

Multiphoton ionization (MPI) time-of-flight mass spectroscopy (TOFMS) and photoelectron spectroscopy (PES) studies of UF6 are reported using focused light from the Nd:YAG laser fundamental (?=1064 nm) and its harmonics (?=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+x fragment ions, even at the lowest laser power densities at which signal could be detected. In general, the doubly charged uranium ion (U2+) intensity is much greater than that of the singly charged uranium ion (U+). For the case of the tunable dye laser experiments, the Un+ (n=1-4) wavelength dependence is relatively unstructured and does not show observable resonance enhancement at known atomic uranium excitation wavelengths. The MPI-PES studies reveal only very slow electrons (?0.5 eV) for all wavelengths investigated. The dominance of the U2+ ion, the absence or very small intensities of UF+x (x=1-3) fragments, the unstructured wavelength dependence, and the preponderance of slow electrons all indicate that mechanisms may exist other than ionization of bare U atoms following the stepwise photodissociation of F atoms from the parent molecule. The data also argue against stepwise photodissociation of UF+x (x=5,6) ions. Neither of the traditional MPI mechanisms (``neutral ladder'' or the ``ionic ladder'') are believed to adequately describe the ionization phenomena observed. We propose that the multiphoton excitation of UF6 under these experimental conditions results in a highly excited molecule, superexcited UF6**. The excitation of highly excited UF6** is proposed to be facilitated by the well known ``giant resonance,'' whose energy level lies in the range of 12-14 eV above that of ground state UF6. The highly excited molecule then primarily dissociates, via multiple channels, into Un+, UF+x, fluorine atoms, and ``slow'' electrons, although dissociation into F- ions is not ruled out.

Armstrong, D. P.; Harkins, D. A.; Compton, R. N.; Ding, D.

1994-01-01

239

Deep drawing of uranium metal  

SciTech Connect

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.

Jackson, R J; Lundberg, M R

1987-01-19

240

Mica Surfaces Stabilize Pentavalent Uranium  

SciTech Connect

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.

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

2005-05-02

241

Consolidation of the Uranium Production Industry  

SciTech Connect

As uranium prices fell from the record-high levels of the late 1970s, high-cost, unsubsidized producers the world over began to curtail operations or exit the uranium business entirely. Since 1980, the number of companies actively involved in uranium mining or exploration has decreased markedly. As this exodus has taken place, existing reserves and production operations have become consolidated in the hands of a shrinking number of producers. Some of these are large, vertically integrated nuclear fuel companies that adhere to a very long-term view of the uranium market. To that end, they continue to acquire reserves for that period when most analysts agree the uranium market will recover and prices will rebound to higher levels. For consumers, however, this consolidation of production and reserves into fewer hands could have serious implications in future years.

Beyer, C.M.

1993-08-01

242

National Uranium Resource Evaluation, Tonopah quadrangle, Nevada  

SciTech Connect

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.

Hurley, B W; Parker, D P

1982-04-01

243

Method for fabricating laminated uranium composites  

DOEpatents

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.

Chapman, L.R.

1983-08-03

244

Uranium Pyrophoricity Phenomena and Prediction  

SciTech Connect

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.

DUNCAN, D.R.

2000-04-20

245

Storage vault for uranium oxide  

SciTech Connect

This paper describes the conceptual design of a vault for storing uranium oxide. Unique features of this vault are the storage racks and the method of surveillance. Uranium oxide packaged in 2-l canisters would be stored in a borated concrete slab placed on the vault floor. The slab would be constructed with a rectangular array of vertical holes, each of which could contain up to two canisters. Each hole would be covered with a square tile to serve as a radiation shield and to prevent casual entry. Canisters would be held one atop the other in a basket attached to the lower surface of each tile. Continual surveillance of each storage position would be provided by a network of light sources and photosensors located along opposite edges of the storage rack such that two light beams intersect perpendicularly above each storage hole but below the radiation shield. Accessing a hole activates a unique pair of photosensors, identifying the position to the value inventory control computer system. Protection against adversarial attack and intrusion detection during nonworking hours would be provided by standard methods used in the industry. The photosensor system would protect against insiders working in collusion to divert material. This would be accomplished by limiting the material vulnerable to diversion to that authorized for access.

Hooker, G.J.

1987-01-01

246

SPECTROPHOTOMETRIC DETERMINATION OF URANIUM IN ORES WITH 8QUINOLINOL  

Microsoft Academic Search

A method for the sensitive and rapid spectrophotometric determination of ; uranium in ores using 8-quinolinol was developed. Uranium is separated by ; extraction with tributylphosphate-kerosene from nitric acid solution. After the ; back-extraction of uranium with ammonium carbonate solution, uranium is ; determined spectrophotometrically with 8-quinolinol. When 1 gram of sample is ; taken, as little as 0.005% of

K. Motojima; H. Yoshida; T. Imahashi

1962-01-01

247

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...

248

Aspects of the permanent storage of uranium tailings  

Microsoft Academic Search

Uranium tailings are generated as solid and liquid wastes in uranium mining\\/milling operations. Since most of the uranium deposits in the world have low grades, millions of tonnes of such wastes are produced annually. Often, the uranium tailings are locally disposed of, using sites with suitable conditions to construct tailings basins. The main concern during the operation of a disposal

A. Al-Hashimi; G. J. Evans; B. Cox

1996-01-01

249

Surficial origin of North American pitchblende and related uranium deposits  

Microsoft Academic Search

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

Langford

1977-01-01

250

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 (Me2PzÃ? ) led to forma- tion of an unprecedented homoleptic

251

Laser removal of loose uranium compound contamination from metal surfaces  

NASA Astrophysics Data System (ADS)

Pulsed laser removal of surface contamination of uranyl nitrate and uranium dioxide from stainless steel has been studied. Most of the loosely bound contamination has been removed at fluence levels below 0.5 J cm -2, leaving about 5% fixed contamination for uranyl nitrate and 15% for uranium dioxide. Both alpha and beta activities are then sufficiently low that contaminated objects can be taken out of a restricted radiation area for re-use. The ratio of beta to alpha activity is found to be a function of particle size and changes during laser removal. In a separate experiment using technetium-99m, the collection of removed radioactivity in the filter was studied and an inventory made of removed and collected contamination.

Roberts, D. E.; Modise, T. S.

2007-04-01

252

Uranium mineralization in southern Victoria Land, Antarctica  

SciTech Connect

For the past 10 antarctic field seasons, an airborne gamma-ray spectrometric survey has been conducted over widely separated parts of the continent. Localized accumulations of both primary and secondary uranium minerals have been discovered at several localities scattered along the Transantarctic Mountains from the Scott Glacier to northern Victoria Land. A number of highly significant radiation anomalies have been discovered in the area between the Koettlitz Glacier and the Pyramid Trough. The occurrences consist of pegmatite vein complexes which contain an association of primary uranium and thorium minerals. Of still greater significance is the fact that abundant secondary uranium minerals were found in association with the primary deposits, and they indicate clearly that uranium is geochemically mobile under the conditions imposed by the arid polar climate that now exists in southern Victoria Land. Preliminary results of a uranium analysis performed by neutron activation indicate a concentration of 0.12% uranium in a composite sample from the two veins. Even higher levels of thorium are present. The nature of the primary uranium mineralization is currently under investigation. Preliminary results are discussed.

Dreschhoff, G.A.M.; Zeller, E.J.

1986-01-01

253

CONTINUOUS PROCESSES FOR THE DIRECT REDUCTION OF URANIUM HEXAFLUORIDE TO URANIUM TETRAFLUORIDE OF HIGH PURITY AND DENSITY  

Microsoft Academic Search

Contrary to the published literature, the single-step reduction of ; uranium hexafluoride to uranium tetrafluoride with hydrogen was found to be ; quantitative; ous process, both safe and economical, was developed and adapted ; for large-scale production use. The uranium tetrafluoride product was of high ; density and purity. The basoc hydrogen reduction method is actually ; uncomplicated; uranium hexafluoride

S. H. Smiley; D. C. Brater

1958-01-01

254

Technical Basis for Assessing Uranium Bioremediation Performance  

SciTech Connect

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

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

2008-04-01

255

Uranium nitride behavior at thermionic temperatures  

NASA Technical Reports Server (NTRS)

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.

Phillips, W. M.

1973-01-01

256

Electronic structure of the uranium monogermanide UGe  

NASA Astrophysics Data System (ADS)

The uranium monogermanide (UGe) crystallizes in the orthorhombic ThIn-type structure (Pbcm space group) in which the uranium and germanium atoms each occupy three crystallographic positions. The electronic structure of UGe compound has been studied using spin-polarized tight binding version of the linear muffin-tin orbital method in the atomic sphere approximation (TB LMTO ASA). The calculations showed that all three types of uranium atoms are magnetically ordered and their spin magnetic moments are equal to: -2.02,+1.88, and -0.24?B/atom.

Szajek, Andrzej

2004-05-01

257

National Uranium Resource Evaluation: Trinidad Quadrangle, Colorado  

SciTech Connect

The Trinidad Quadrangle, in south-central Colorado, was evaluated for uranium favorability according to the National Uranium Resource Evaluation criteria. Literature research, uranium-occurrence investigations, general surface reconnaissance, subsurface studies, and geochemical and hydrochemical sampling were conducted to evaluate the geologic environments in the quadrangle. Portions of the Pennsylvanian-Permian Sangre de Cristo Formation and the Tertiary Alamosa were identified as favorable. Precambrian, Paleozoic, Mesozoic, and Cenozoic environments were identified as unfavorable. Eleven environments within the Paleozoic and Cenozoic were unevaluated.

Not Available

1982-06-01

258

Capstone Depleted Uranium Aerosols: Generation and Characterization  

SciTech Connect

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

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

2004-10-19

259

Status of highly loaded uranium-zirconium hydride Low Enriched Uranium (LEU) fuel programs  

Microsoft Academic Search

The LEU uranium-zirconium hydride fuel has successfully completed all essential development testing and is offered commercially in both the 20 weight percent and 45 weight percent uranium concentrations for existing TRIGA reactors and as a conversion fuel for plate-type reactors. Several reactor facilities have already begun conversion to LEU uranium-zirconium hydride fuel. Currently, U-ZrH LEU fuel is in use in

1984-01-01

260

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

SciTech Connect

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

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

1997-07-01

261

Synthesis of uranium nitride and uranium carbide powder by carbothermic reduction  

SciTech Connect

Uranium nitride and uranium carbide are being considered as high burnup fuels in next generation nuclear reactors and accelerated driven systems for the transmutation of nuclear waste. The same characteristics that make nitrides and carbides candidates for these applications (i.e. favorable thermal properties, mutual solubility of nitrides, etc.), also make these compositions candidate fuels for space nuclear reactors. In this paper, we discuss the synthesis and characterization of depleted uranium nitride and carbide for a space nuclear reactor program. Importantly, this project emphasized that to synthesize high quality uranium nitride and carbide, it is necessary to understand the exact stoichiometry of the oxide feedstock. (authors)

Dunwoody, J.T.; Stanek, C.R.; McClellan, K.J.; Voit, S.L.; Volz, H.M. [Los Alamos National Laboratory, Los Alamos, New Mexico (United States); Hickman, R.R. [NASA Marshall Space Flight Center, Huntsville, Alabama (United States)

2007-07-01

262

Isotopic evidence of natural uranium and spent fuel uranium releases into the environment.  

PubMed

Uranium and plutonium isotopes were measured in soils, sediments and waters in an area subject to the past and present discharges from the uranium conversion plant of Malvési (France). The isotopes (236)U and (239)Pu are well known activation products of uranium and they prove to be powerful tracers of spent fuel releases in soils and sediments. On the other hand (234)U and (238)U activities measured in waters can be used to distinguish between releases and background uranium sources. Such findings contribute to improve the monitoring of the actinides releases by nuclear fuel facilities (mining sites, conversion, enrichment and fuel plants, reprocessing plants). PMID:21132170

Pourcelot, L; Boulet, B; Le Corre, C; Loyen, J; Fayolle, C; Tournieux, D; Van Hecke, W; Martinez, B; Petit, J

2011-02-01

263

A study of uranium lung clearance at a uranium processing plant  

SciTech Connect

A study has been made of the retention of uranium in the lungs of persons exposed chronically, to low levels of uranium aerosols at the Y-12 Plant. A new characterization of the workplace aerosols shows an activity median aerodynamic diameter of 8 to be representative of the uranium oxides handled at the Y-12 Plant. The usual ICRP respiratory-system model is employed in conjunction with bioassay data from worker exposures to deduce a new set of parameters to describe lung clearance of these aerosols. This new assessment leads to good agreement between in vivo and in vitro estimates of uranium lung burdens.

Barber, J.M. [Oak Ridge National Lab., TN (United States); Forrest, R.D. [Univ. of Massachusetts, Lowell, MA (United States)

1995-05-01

264

A study of uranium lung clearance at a uranium processing plant.  

PubMed

A study has been made of the retention of uranium in the lungs of persons exposed chronically to low levels of uranium aerosols at the Y-12 Plant. A new characterization of the workplace aerosols shows an activity median aerodynamic diameter of 8 microns to be representative of the uranium oxides handled at the Y-12 Plant. The usual ICRP respiratory-system model is employed in conjunction with bioassay data from worker exposures to deduce a new set of parameters to describe lung clearance of these aerosols. This new assessment leads to good agreement between in vivo estimates of uranium lung burdens. PMID:7730062

Barber, J M; Forrest, R D

1995-05-01

265

Cogema acquires TOTAL's uranium assets  

SciTech Connect

On April 28, France's nuclear fuel cycle conglomerate Cogema and petroleum group TOTAL announced a plan in which Cogema will assume ownership of TOTAL's uranium assets worldwide, and as part of the deal, each firm will acquire shares of the other. On June 2, the agreement will be submitted to shareholders and, assuming it is approved, will go into effect this year. The agreement calls for TOTAL to acquire a 10.8-percent share in Cogema, thus becoming its first private sector shareholder, by underwriting a reserve capital increase of FF1.5 billion (approximately US$283 million). In return, Cogema will pay FF2.52 billion for approximately 4.3 percent of TOTAL, as part of a reserve capital increase totalling FF4.07 billion.

Not Available

1993-06-01

266

Energy spectrum of sputtered uranium  

NASA Technical Reports Server (NTRS)

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.

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

1977-01-01

267

Relative probabilities of the uranium isotopes for thorium x-ray emission and fluorescence of uranium x-rays  

Microsoft Academic Search

This paper reports that both thorium x-rays from decaying uranium isotopes and self-fluoresced uranium x-rays are prominent in high-resolution gamma-ray spectra of uranium-bearing materials. Useful application of the information carried by those x-rays has been curtailed because the probabilities of the uranium isotopes for thorium x-ray emission and for uranium x-ray fluorescence have not been known. By analyzing enrichment-meter geometry

1991-01-01

268

TRIMOLECULAR REACTIONS OF URANIUM HEXAFLUORIDE WITH WATER  

SciTech Connect

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

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

2010-02-25

269

The emission coefficient of uranium plasmas  

NASA Technical Reports Server (NTRS)

The emission coefficient for uranium plasmas (Temperature: 8000 K) was measured for the wavelength range (200 A - 6000 A). The results are compared to theory and other measurements. The absorption coefficient for the same wavelength interval is also given.

Schneider, R. T.; Campbell, H. D.; Mack, J. M.

1973-01-01

270

Compatibility of buffered uranium carbides with tungsten.  

NASA Technical Reports Server (NTRS)

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.

Phillips, W. M.

1971-01-01

271

Lung cancer among Navajo uranium miners  

SciTech Connect

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.

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

1982-04-01

272

Innovative design of uranium startup fast reactors  

E-print Network

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

Fei, Tingzhou

2012-01-01

273

Process for reducing beta activity in uranium  

DOEpatents

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.

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

1985-04-11

274

Interim Report on Uranium Metal Segregation Testing  

SciTech Connect

This report describes the preliminary results of laboratory and bench-scale vendor testing to evaluate the effectiveness of the gravity mineral concentration technology for removing and concentrating uranium metal from K Basin sludge.

Schmidt, Andrew J.; Elmore, Monte R.

2004-04-18

275

Process for reducing beta activity in uranium  

DOEpatents

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

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

1986-01-01

276

Empirical modeling of uranium nitride fuels  

E-print Network

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...

Brozak, Daniel Edward

1987-01-01

277

Evolution of uranium and thorium minerals  

Microsoft Academic Search

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),

R. M. Hazen; R. C. Ewing; D. A. Sverjensky

2009-01-01

278

Depleted uranium: A DOE management guide  

SciTech Connect

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.

NONE

1995-10-01

279

Simple Method for Depleted Uranium Determination  

Microsoft Academic Search

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),

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

2003-01-01

280

Uranium induces apoptosis in lung epithelial cells  

Microsoft Academic Search

Uranium is a naturally occurring radioactive material present everywhere in the environment. It is toxic because of its chemical\\u000a or radioactive properties. Uranium enters environment mainly from mines and industry and cause threat to human health by accumulating\\u000a in lungs as a result of inhalation. In our previous study, we have shown the effectiveness of antioxidant system response\\u000a to the

Adaikkappan Periyakaruppan; Shubhashish Sarkar; Prabakaran Ravichandran; Bindu Sadanandan; Chidananda S. Sharma; Vani Ramesh; Joseph C. Hall; Renard Thomas; Bobby L. Wilson; Govindarajan T. Ramesh

2009-01-01

281

Decommissioning of an enriched uranium processing facility  

Microsoft Academic Search

The Los Alamos National Laboratory TA-21, Buildings 3 and 4 South decontamination and decommissioning (D&D) project began remediation on September 20, 1993. The project is one of the largest U.S. Department of Energy-sponsored D&D projects currently under way. The project involves the decontamination, dismantlement, and demolition of two enriched-uranium processing buildings, which is an area of â¼10000 ft². The enriched-uranium

Stout

1994-01-01

282

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

SciTech Connect

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.

NONE

1995-07-05

283

Determination of uranium in minerals and rocks.  

PubMed

A method is described for the determination of uranium in minerals and rocks by spectrophotometry and fluorimetry. After treatment of the sample with hydrochloric acid, uranium is separated from matrix elements by adsorption on a column of the strongly basic anion-exchange resin Dowex 1 x 8 from an organic solvent system consisting of IBMK, tetrahydrofuran and 12M hydrochloric acid (1:8:1 v v ). Following removal of iron, molybdenum and co-adsorbed elements by washing first with the organic solvent system and then with 6M hydrochloric acid, the uranium is eluted with 1M hydrochloric acid. In the eluate, uranium is determined by means of the spectrophotometric arsenazo III method or fluorimetrically. The suitability of the method for the determination of both trace and larger amounts of uranium was tested by analysing numerous geochemical reference samples with uranium contents in the range 10(-1)-10(4) ppm. In practically all cases very good agreement of results was obtained. PMID:18961856

Korkisch, J; Hübner, H

1976-04-01

284

Microbial transformation of uranium in wastes  

SciTech Connect

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.

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

285

The United States Uranium Industry, 1993  

SciTech Connect

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.

Chenoweth, W.L.

1993-08-01

286

Electrochemical method of producing eutectic uranium alloy and apparatus  

DOEpatents

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

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

1995-01-01

287

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

Microsoft Academic Search

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

A. Meinrath; P. Schneider; G. Meinrath

2003-01-01

288

Selected uranium and uranium-thorium occurrences in New Hampshire  

USGS Publications Warehouse

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.

Bothner, W.A.

1978-01-01

289

49 CFR 173.426 - Excepted packages for articles containing natural uranium or thorium.  

Code of Federal Regulations, 2010 CFR

...packages for articles containing natural uranium or thorium. 173.426 Section 173...packages for articles containing natural uranium or thorium. A manufactured article...radioactive) material content is natural uranium, unirradiated depleted uranium...

2010-10-01

290

49 CFR 173.426 - Excepted packages for articles containing natural uranium or thorium.  

Code of Federal Regulations, 2011 CFR

...packages for articles containing natural uranium or thorium. 173.426 Section 173...packages for articles containing natural uranium or thorium. A manufactured article...radioactive) material content is natural uranium, unirradiated depleted uranium...

2011-10-01

291

49 CFR 173.426 - Excepted packages for articles containing natural uranium or thorium.  

...packages for articles containing natural uranium or thorium. 173.426 Section 173...packages for articles containing natural uranium or thorium. A manufactured article...radioactive) material content is natural uranium, unirradiated depleted uranium...

2014-10-01

292

49 CFR 173.426 - Excepted packages for articles containing natural uranium or thorium.  

Code of Federal Regulations, 2013 CFR

...packages for articles containing natural uranium or thorium. 173.426 Section 173...packages for articles containing natural uranium or thorium. A manufactured article...radioactive) material content is natural uranium, unirradiated depleted uranium...

2013-10-01

293

49 CFR 173.426 - Excepted packages for articles containing natural uranium or thorium.  

Code of Federal Regulations, 2012 CFR

...packages for articles containing natural uranium or thorium. 173.426 Section 173...packages for articles containing natural uranium or thorium. A manufactured article...radioactive) material content is natural uranium, unirradiated depleted uranium...

2012-10-01

294

Synthesis of uranium nitride and uranium carbide powder by carbothermic reduction  

Microsoft Academic Search

Uranium nitride and uranium carbide are being considered as high burnup fuels in next generation nuclear reactors and accelerated driven systems for the transmutation of nuclear waste. The same characteristics that make nitrides and carbides candidates for these applications (i.e. favorable thermal properties, mutual solubility of nitrides, etc.), also make these compositions candidate fuels for space nuclear reactors. In this

J. T. Dunwoody; C. R. Stanek; K. J. McClellan; S. L. Voit; H. M. Volz; R. R. Hickman

2007-01-01

295

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

Microsoft Academic Search

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.

Jesse D Edmands; Daniel J Brabander; Drew S Coleman

2001-01-01

296

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

Microsoft Academic Search

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

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

2009-01-01

297

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

SciTech Connect

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 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 an Effect Group. A discriminant analysis was used to build a model equation to predict the Effect Group based on the amount of uranium in the kidneys. The model equation was able to predict the Effect Group with 85% accuracy. The risk model was used to predict the Effect Group for Soldiers exposed to DU as a result of friendly fire incidents during the 1991 Gulf War. This model equation can also be used to predict the Effect Group of new cases in which acute exposures to uranium have occurred.

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

2009-02-26

298

Uranium removal from soils: An overview from the Uranium in Soils Integrated Demonstration program  

SciTech Connect

An integrated approach to remove uranium from uranium-contaminated soils is being conducted by four of the US Department of Energy national laboratories. In this approach, managed through the Uranium in Soils Integrated Demonstration program at the Fernald Environmental Management Project, Fernald, Ohio, these laboratories are developing processes that selectively remove uranium from soil without seriously degrading the soil`s physicochemical characteristics or generating waste that is difficult to manage or dispose of. These processes include traditional uranium extractions that use carbonate as well as some nontraditional extraction techniques that use citric acid and complex organic chelating agents such as naturally occurring microbial siderophores. A bench-scale engineering design for heap leaching; a process that uses carbonate leaching media shows that >90% of the uranium can be removed from the Fernald soils. Other work involves amending soils with cultures of sulfur and ferrous oxidizing microbes or cultures of fungi whose role is to generate mycorrhiza that excrete strong complexers for uranium. Aqueous biphasic extraction, a physical separation technology, is also being evaluated because of its ability to segregate fine particulate, a fundamental requirement for soils containing high levels of silt and clay. Interactions among participating scientists have produced some significant progress not only in evaluating the feasibility of uranium removal but also in understanding some important technical aspects of the task.

Francis, C.W. [Oak Ridge National Lab., TN (United States); Brainard, J.R.; York, D.A. [Los Alamos National Lab., NM (United States); Chaiko, D.J. [Argonne National Lab., IL (United States); Matthern, G. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

1994-09-01

299

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

E-print Network

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.

Drees, Angelika

2013-01-01

300

Microbial Uranium Immobilization Independent of Nitrate Reduction  

SciTech Connect

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.

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

301

Microbial uranium immobilization independent of nitrate reduction.  

PubMed

At many uranium processing and handling facilities, including sites in the US 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 and require that the persistent nitrate must first and continuously be removed or transformed prior to uranium being a preferred electron acceptor. This work investigated the possibility of stimulating nitrate-indifferent, pH-tolerant microorganisms to achieve bioreduction of U(VI) despite nitrate persistence. Enrichments from U-contaminated sediments demonstrated nearly complete reduction of uranium with very little loss of nitrate from pH 5.7-6.2 using methanol or glycerol as a carbon source. Bacterial 16S rRNA genes were amplified from uranium-reducing enrichments (pH 5.7-6.2) and sequenced. Phylogenetic analyses classified the clone sequences into four distinct clusters. Data from sequencing and terminal-restriction fragment length polymorphism (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. PMID:17686028

Madden, Andrew S; Smith, April C; Balkwill, David L; Fagan, Lisa A; Phelps, Tommy J

2007-09-01

302

Atomistic Properties of Y Uranium  

SciTech Connect

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.

Benjamin Beeler; Chaitanya Deo; Mmichael Baskes; Maria Okuniewski

2012-02-01

303

Uranium transformations in static microcosms.  

SciTech Connect

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.

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

304

Recovery of uranium from seawater  

SciTech Connect

This report is the proceedings of a topical meeting on the recovery of uranium from seawater, held at the Massachusetts Institute of Technology on December 1-2, 1980. The meeting was sponsored by the United States Department of Energy and hosted by the MIT Energy Laboratory and Nuclear Engineering Department. Workers from six different countries presented a total of sixteen papers in three major categories: the state-of-the-art resulting from past efforts; detailed results from sorber preparation and performance experiments; and overall system design aspects. Sorbers discussed include hydrous titanium oxide, ion exchange resins, chitosan, humic acids and activated carbon. Systems for contacting seawater with the sorber include actively pumped, current and wave-powered concepts. Filter configurations include thin multilayer stacks, fluidized beds and free falling particles. Several of the researchers estimated eventual production costs in the 200 to 400 $/lb U/sub 3/O/sub 8/ range, although values as high as 2000 $/lb were also quoted. The bulk of the proceedings is comprised of the unedited papers, as provided by the authors. The proceedings also include edited transcripts of the discussions on all papers and the panel and concluding discussions. All papers have been abstracted separately.

Best, F.R.; Driscoll, M.J. (eds.)

1980-12-01

305

In vitro dissolution of uranium oxide by baboon alveolar macrophages.  

PubMed Central

In vitro cellular dissolution tests for insoluble forms of uranium oxide are technically difficult with conventional methodology using adherent alveolar macrophages. The limited number of cells per flask and the slow dissolution rate in a large volume of nutritive medium are obvious restricting factors. Macrophages in suspension cannot be substituted because they represent different and poorly reproducible functional subtypes with regard to activation and enzyme secretion. Preliminary results on the dissolution of uranium oxide using immobilized alveolar macrophages are promising because large numbers of highly functional macrophages can be cultured in a limited volume. Cells were obtained by bronchoalveolar lavages performed on baboons (Papio papio) and then immobilized after the phagocytosis of uranium octoxide (U3O8) particles in alginate beads linked with Ca2+. The dissolution rate expressed as percentage of initial uranium content in cells was 0.039 +/- 0.016%/day for particles with a count median geometric diameter of 3.84 microns(sigma g = 1.84). A 2-fold increase in the dissolution rate was observed when the same number of particles was immobilized without macrophages. These results, obtained in vitro, suggest that the U3O8 preparation investigated should be assigned to inhalation class Y as recommended by the International Commission on Radiological Protection. Future experiments are intended to clarify this preliminary work and to examine the dissolution characteristics of other particles such as uranium dioxide. It is recommended that the dissolution rate should be measured over an interval of 3 weeks, which is compatible with the survival time of immobilized cells in culture and may reveal transformation states occurring with aging of the particles. PMID:1396447

Poncy, J L; Metivier, H; Dhilly, M; Verry, M; Masse, R

1992-01-01

306

In vitro dissolution of uranium oxide by baboon alveolar macrophages  

SciTech Connect

In vitro cellular dissolution tests for insoluble forms of uranium oxide are technically difficult with conventional methodology using adherent alveolar macrophages. The limited number of cells per flask and the slow dissolution rate in a large volume of nutritive medium are obvious restricting factors. macrophages in suspension cannot be substituted because they represent different and poorly reproducible functional subtypes with regard to activation and enzyme secretion. Preliminary results on the dissolution of uranium oxide using immobilized alveolar macrophages are promising because large numbers of highly function macrophages can be cultured in a limited volume. Cells were obtained by bronchoalveolar lavages performed on baboons (Papio papio) and then immobilized after the phagocytosis of uranium octoxide (U[sub 3]O[sub 8]) particles in alginate beads linked with Ca[sup 2+]. The dissolution rate expressed as percentage of initial uranium content in cells was 0.039 [+-] 0.016%/day for particles with a count median geometric diameter of 3.84 [mu]m([sigma][sub g] = 1.84). A 2-fold increase in the dissolution rate was observed when the same number of particles was immobilized without macrophages. These results, obtained in vitro, suggest that the U[sub 3]O[sub g] preparation investigated should be assigned to inhalation class Y as recommended by the International Commission on Radiological Protection. Future experiments are intended to clarify this preliminary work and to examine the dissolution characteristics of other particles such as uranium dioxide. It is recommended that the dissolution rate should be measured over an interval of 3 weeks, which is compatible with the survival time of immobilized cells in culture and may reveal transformation states occurring with aging of the particles. 23 refs., 3 figs.

Poncy, J.L.; Dhilly, M.; Verry, M. (CEA/DSV/DPTE/LRT, Bruyeres le Chatel (France)); Metivier, H. (CEA/IPSN/DRSN, Fontenay aux Roses (France)); Masse, R. (CEA/DSV/DPTE, Fontenay aux Roses (France))

1992-07-01

307

Characterizing In Situ Uranium and Groundwater Flux  

NASA Astrophysics Data System (ADS)

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%.

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

308

Search for uranium in western United States  

USGS Publications Warehouse

The search for uranium in the United States is one of the most intensive ever made for any metal during our history. The number of prospectors and miners involved is difficult to estimate but some measure of the size of the effort is indicated by the fact that about 500 geologists are employed by government and industry in the work--more than the total number of geologists engaged in the study of all other minerals together except oil. The largest part of the effort has been concentrated in the western states. No single deposit of major importance by world standards has been discovered but the search has led to the discovery of important minable deposits of carnotite and related minerals on the Colorado Plateau; of large, low grade deposits of uranium in phosphates in the northwestern states and in lignites in the Dakotas, Wyoming, Idaho and New Mexico; and of many new and some promising occurrences of uranium in carnotite-like deposits and in vein deposits. Despite the fact that a large number of the districts considered favorable for the occurrence of uranium have already been examined, the outlook for future discoveries is bright, particularly for uranium in vein and in carnotite-like deposits in the Rocky Mountain States.

McKelvey, Vincent Ellis

1953-01-01

309

Plutonium and uranium adsorption on monosodium titanate  

SciTech Connect

Adsorption of Pu and U onto monosodium titanate (MST) in alkaline salt solution was measured. Changes in MST particle size distribution do not significantly affect the loadings of actinides. Max loading of plutonium-239 is 0.68 wt% at 0.79 mg/L Pu, below the infinitely safe value of 0.80 wt%. Max loading of uranium-235 onto MST is 1.4 wt% at a concentration of 20.3 [plus minus] 2.0 mg/L U, slightly higher than the calculated infinitely safe limit of 1.2 wt%. Experimental data indicated there is competition between plutonium and uranium for sites on the MST, and that the loading will favor the higher concentration species. Since the solubility of uranium is 10--100 times higher than of plutonium, uranium will be loaded to its maximum limit, but plutonium will be below its maximum limit. To ensure that the concentration of fissile materials cannot exceed nuclear safety limits, it is recommended that plutonium and uranium solubility tests be conducted with solutions which bound the compositions of waste which will be treated in ITP process.

Hobbs, D.T.; Walker, D.D.

1992-08-13

310

Plutonium and uranium adsorption on monosodium titanate  

SciTech Connect

Adsorption of Pu and U onto monosodium titanate (MST) in alkaline salt solution was measured. Changes in MST particle size distribution do not significantly affect the loadings of actinides. Max loading of plutonium-239 is 0.68 wt% at 0.79 mg/L Pu, below the infinitely safe value of 0.80 wt%. Max loading of uranium-235 onto MST is 1.4 wt% at a concentration of 20.3 {plus_minus} 2.0 mg/L U, slightly higher than the calculated infinitely safe limit of 1.2 wt%. Experimental data indicated there is competition between plutonium and uranium for sites on the MST, and that the loading will favor the higher concentration species. Since the solubility of uranium is 10--100 times higher than of plutonium, uranium will be loaded to its maximum limit, but plutonium will be below its maximum limit. To ensure that the concentration of fissile materials cannot exceed nuclear safety limits, it is recommended that plutonium and uranium solubility tests be conducted with solutions which bound the compositions of waste which will be treated in ITP process.

Hobbs, D.T.; Walker, D.D.

1992-08-13

311

Urine proteomic profiling of uranium nephrotoxicity.  

PubMed

Uranium is used in many chemical forms in civilian and military industries and is a known nephrotoxicant. A key issue in monitoring occupational exposure is to be able to evaluate the potential damage to the body, particularly the kidney. In this study we used innovative proteomic techniques to analyse urinary protein modulation associated with acute uranium exposure in rats. Given that the rat urinary proteome has rarely been studied, we first identified 102 different proteins in normal urine, expanding the current proteome data set for this central animal in toxicology. Rats were exposed intravenously to uranyl nitrate at 2.5 and 5 mg/kg and samples were collected 24 h later. Using two complementary proteomic methods, a classic 2-DE approach and semi-quantitative SDS-PAGE-LC-MS/MS, 14 modulated proteins (7 with increased levels and 7 with decreased levels) were identified in urine after uranium exposure. Modulation of three of them was confirmed by western blot. Some of the modulated proteins corresponded to proteins already described in case of nephrotoxicity, and indicated a loss of glomerular permeability (albumin, alpha-1-antiproteinase, serotransferrin). Others revealed tubular damage, such as EGF and vitamin D-binding protein. A third category included proteins never described in urine as being associated with metal stress, such as ceruloplasmin. Urinary proteomics is thus a valuable tool to profile uranium toxicity non-invasively and could be very useful in follow-up in case of accidental exposure to uranium. PMID:19336034

Malard, Véronique; Gaillard, Jean-Charles; Bérenguer, Frédéric; Sage, Nicole; Quéméneur, Eric

2009-06-01

312

Prospects for the recovery of uranium from seawater  

E-print Network

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 ...

Best, F. R.

1980-01-01

313

Reducing the environmental impact of uranium in-situ recovery.  

SciTech Connect

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.

Siegel, Malcolm Dean; Simmons, Ardyth

2010-10-01

314

Assessments of long-term uranium supply availability  

E-print Network

The future viability of nuclear power will depend on the long-term availability of uranium. A two-form uranium supply model was used to estimate the date at which peak production will occur. The model assumes a constant ...

Zaterman, Daniel R

2009-01-01

315

What Price Energy? Hazards of Uranium Mining in the Southwest.  

ERIC Educational Resources Information Center

This article describes the hazards, sickness, death and destruction caused by uranium mining/nuclear energy development in the Southwest focusing on the experiences of several Indian uranium mines. (RTS)

Barry, Tom

1979-01-01

316

RESOLUTION OF URANIUM ISOTOPES WITH KINETIC PHOSPHORESCENCE ANALYSIS  

SciTech Connect

This study was conducted to test the ability of the Chemchek™ Kinetic Phosphorescence Analyzer Model KPA-11 with an auto-sampler to resolve the difference in phosphorescent decay rates of several different uranium isotopes, and therefore identify the uranium isotope ratios present in a sample. Kinetic phosphorescence analysis (KPA) is a technique that provides rapid, accurate, and precise determination of uranium concentration in aqueous solutions. Utilizing a pulsed-laser source to excite an aqueous solution of uranium, this technique measures the phosphorescent emission intensity over time to determine the phosphorescence decay profile. The phosphorescence intensity at the onset of decay is proportional to the uranium concentration in the sample. Calibration with uranium standards results in the accurate determination of actual concentration of the sample. Different isotopes of uranium, however, have unique properties which should result in different phosphorescence decay rates seen via KPA. Results show that a KPA is capable of resolving uranium isotopes.

Miley, Sarah M.; Hylden, Anne T.; Friese, Judah I.

2013-04-01

317

Uranium geochemistry on the Amazon shelf: Evidence for uranium release from bottom sediments  

SciTech Connect

In Amazon-shelf waters, as salinity increases to 36.5 x 10{sup {minus}3}, dissolved uranium activities increase to a maximum of 4.60 dpm 1{sup {minus}1}. This value is much higher than the open-ocean value (2.50 dpm 1{sup {minus}1}), indicating a source of dissolved uranium to shelf waters in addition to that supplied from open-ocean and riverine waters. Uranium activities are much lower for surface sediments in the Amazon-shelf sea bed (mean: 0.69 {plus minus} .09 dpm g{sup {minus}1}) than for suspended sediments in the Amazon river (1.82 dpm g{sup {minus}1}). Data suggest that the loss of particulate uranium from riverine sediments is probably the result of uranium desorption from the ferric-oxyhydroxide coatings on sediment particles, and/or uranium release by mobilization of the ferric oxyhydroxides. The total flux of dissolved {sup 238}U from the Amazon shelf (about 1.2 x 10{sup 15} dpm yr{sup {minus}1}) constitutes about 15% of uranium input to the world ocean, commensurate to the Amazon River's contribution to world river-water discharge. Measurement of only the riverine flux of dissolved {sup 238}U underestimates, by a factor of about 5, the flux of dissolved {sup 238}U from the Amazon shelf to the open ocean.

McKee, B.A.; DeMaster, D.J.; Nittrouer, C.A. (North Carolina State Univ., Raleigh (USA))

1987-10-01

318

Process for the in-situ leaching of uranium  

SciTech Connect

Process for the in-situ leaching of uranium employing an alkaline lixiviant and an alkali metal or alkaline earth metal hypochlorite as an oxidizing agent. The use of the hypochlorite oxidant results in significantly higher uranium recoveries and leaching rates than those attained by the use of conventional oxidants. The invention is particularly suitable for use in subterranean deposits in which the uranium mineral is associated with carbonaceous material which retards access to the uranium by the lixiviant.

Habib, E.T.; Vogt, T.C.

1982-01-26

319

Different genotoxic profiles between depleted and enriched uranium  

Microsoft Academic Search

Uranium is an alpha-particle-emitting heavy metal. Its genotoxicity results from both its chemical and its radiological properties that vary with its isotopic composition (12% enriched uranium in 235U (EU) has a specific activity 20 times higher than 0.3% depleted uranium in 235U (DU)). The influence of the isotopic composition of uranium on its genotoxic profile (clastogenic\\/aneugenic) has never been described.

C. Darolles; D. Broggio; A. Feugier; S. Frelon; I. Dublineau; M. De Meo; F. Petitot

2010-01-01

320

Modeling Uranium-Proton Ion Exchange in Biosorption  

E-print Network

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

Volesky, Bohumil

321

Depleted uranium plasma reduction system study  

SciTech Connect

A system life-cycle cost study was conducted of a preliminary design concept for a plasma reduction process for converting depleted uranium to uranium metal and anhydrous HF. The plasma-based process is expected to offer significant economic and environmental advantages over present technology. Depleted Uranium is currently stored in the form of solid UF{sub 6}, of which approximately 575,000 metric tons is stored at three locations in the U.S. The proposed system is preconceptual in nature, but includes all necessary processing equipment and facilities to perform the process. The study has identified total processing cost of approximately $3.00/kg of UF{sub 6} processed. Based on the results of this study, the development of a laboratory-scale system (1 kg/h throughput of UF6) is warranted. Further scaling of the process to pilot scale will be determined after laboratory testing is complete.

Rekemeyer, P.; Feizollahi, F.; Quapp, W.J.; Brown, B.W.

1994-12-01

322

Cleaning of uranium vs machine coolant formulations  

SciTech Connect

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.

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

1984-10-01

323

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

Microsoft Academic Search

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

G. M. Mudd

324

THE SPECTROPHOTOMETRIC DETERMINATION OF URANIUM WITH XYLENOL ORANGE  

Microsoft Academic Search

A new spectrophotometric method for determining trace amounts of uranium ; was developed. This method is based on the coloration of xylenol orange with ; uranium(IV) formed by the reduction of uranium(VI) in the presence of ascorbic ; acid. The effects of the pH value, reagent, and boiling time were thoroughly ; investigated, and experimental conditions which make possible the

Makoto Otomo

1963-01-01

325

Uranium Mill Tailings Remedial Action Project surface project management plan  

SciTech Connect

This Project Management Plan describes the planning, systems, and organization that shall be used to manage the Uranium Mill Tailings Remedial Action Project (UMTRA). US DOE is authorized to stabilize and control surface tailings and ground water contamination at 24 inactive uranium processing sites and associated vicinity properties containing uranium mill tailings and related residual radioactive materials.

Not Available

1994-09-01

326

Calculating Capstone Depleted Uranium Aerosol Concentrations from Beta Activity Measurements  

Microsoft Academic Search

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.

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

2009-01-01

327

31 CFR 540.318 - Uranium Hexafluoride (UF6).  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Uranium Hexafluoride (UF6). 540.318 Section...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.318 Uranium Hexafluoride (UF6). The term...

2011-07-01

328

Recovery of uranium from biological adsorbents?desorption equilibrium  

Microsoft Academic Search

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

M. Tsezos

1984-01-01

329

10 CFR 39.49 - Uranium sinker bars.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 2013-01-01 false Uranium sinker bars. 39.49 Section 39.49...FOR WELL LOGGING Equipment § 39.49 Uranium sinker bars. The licensee may use a uranium sinker bar in well logging applications...

2013-01-01

330

EPA Uranium Program Update Loren W. Setlow and  

E-print Network

EPA Uranium Program Update Loren W. Setlow and Reid J. Rosnick Environmental Protection Agency Office of Radiation and Indoor Air (6608J) Washington, DC 20460 NMA/NRC Uranium Recovery Workshop April 30, 2008 #12;2 Overview EPA Radiation protection program Uranium reports and abandoned mine lands

331

10 CFR 39.49 - Uranium sinker bars.  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 2012-01-01 false Uranium sinker bars. 39.49 Section 39.49...FOR WELL LOGGING Equipment § 39.49 Uranium sinker bars. The licensee may use a uranium sinker bar in well logging applications...

2012-01-01

332

Uranium Reduction in Sediments under Diffusion-Limited Transport of  

E-print Network

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

Hazen, Terry

333

10 CFR 39.49 - Uranium sinker bars.  

... 2014-01-01 2014-01-01 false Uranium sinker bars. 39.49 Section 39.49...FOR WELL LOGGING Equipment § 39.49 Uranium sinker bars. The licensee may use a uranium sinker bar in well logging applications...

2014-01-01

334

31 CFR 540.318 - Uranium Hexafluoride (UF6).  

...2014-07-01 2014-07-01 false Uranium Hexafluoride (UF6). 540.318 Section...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.318 Uranium Hexafluoride (UF6). The term...

2014-07-01

335

Bioremediation of Uranium Plumes with Nano-scale  

E-print Network

Bioremediation of Uranium Plumes with Nano-scale Zero-valent Iron Angela Athey Advisers: Dr. Reyes Undergraduate Student Fellowship Program April 15, 2011 #12;Main Sources of Uranium Natural · Leaching from(IV) (UO2[s], uraninite) Anthropogenic · Release of mill tailings during uranium mining - Mobilization

Fay, Noah

336

31 CFR 540.315 - Uranium-235 (U235).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Uranium-235 (U235). 540.315 Section...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.315 Uranium-235 (U235). The term...

2013-07-01

337

Plutonium recovery from spent reactor fuel by uranium displacement  

DOEpatents

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.

Ackerman, J.P.

1992-03-17

338

Microbial Janitors: Enabling natural microbes to clean up uranium contamination  

E-print Network

Microbial Janitors: Enabling natural microbes to clean up uranium contamination Oak Ridge to the development of the atomic bomb. Uranium enrichment activities on the Oak Ridge Reservation in the 1940s until then the uranium and nitrate contamination has spread through the ground and now covers an area of about 7 km

339

31 CFR 540.318 - Uranium Hexafluoride (UF6).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Uranium Hexafluoride (UF6). 540.318 Section...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.318 Uranium Hexafluoride (UF6). The term...

2013-07-01

340

31 CFR 540.315 - Uranium-235 (U235).  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Uranium-235 (U235). 540.315 Section...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.315 Uranium-235 (U235). The term...

2010-07-01

341

31 CFR 540.318 - Uranium Hexafluoride (UF6).  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Uranium Hexafluoride (UF6). 540.318 Section...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.318 Uranium Hexafluoride (UF6). The term...

2012-07-01

342

Plutonium recovery from spent reactor fuel by uranium displacement  

DOEpatents

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.

Ackerman, John P. (Downers Grove, IL)

1992-01-01

343

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

344

Estimating terrestrial uranium and thorium by antineutrino flux measurements  

E-print Network

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

Mcdonough, William F.

345

31 CFR 540.318 - Uranium Hexafluoride (UF6).  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Uranium Hexafluoride (UF6). 540.318 Section...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.318 Uranium Hexafluoride (UF6). The term...

2010-07-01

346

31 CFR 540.315 - Uranium-235 (U235).  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Uranium-235 (U235). 540.315 Section...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.315 Uranium-235 (U235). The term...

2011-07-01

347

31 CFR 540.315 - Uranium-235 (U235).  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Uranium-235 (U235). 540.315 Section...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.315 Uranium-235 (U235). The term...

2012-07-01

348

Effects of uranium on the metabolism of zebrafish, Danio rerio  

E-print Network

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

Paris-Sud XI, Université de

349

10 CFR 39.49 - Uranium sinker bars.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 2010-01-01 false Uranium sinker bars. 39.49 Section 39.49...FOR WELL LOGGING Equipment § 39.49 Uranium sinker bars. The licensee may use a uranium sinker bar in well logging applications...

2010-01-01

350

Soil to plant transfer of 238 Th on a uranium  

E-print Network

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

Hu, Qinhong "Max"

351

31 CFR 540.315 - Uranium-235 (U235).  

...2014-07-01 2014-07-01 false Uranium-235 (U235). 540.315 Section...DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.315 Uranium-235 (U235). The term...

2014-07-01

352

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

353

10 CFR 39.49 - Uranium sinker bars.  

Code of Federal Regulations, 2011 CFR

... 2011-01-01 2011-01-01 false Uranium sinker bars. 39.49 Section 39.49...FOR WELL LOGGING Equipment § 39.49 Uranium sinker bars. The licensee may use a uranium sinker bar in well logging applications...

2011-01-01

354

Measurement of enriched uranium and uranium-aluminum fuel materials with the AWCC  

SciTech Connect

The active well coincidence counter (AWCC) was calibrated at the Chalk River Nuclear Laboratories (CRNL) for the assay of 93%-enriched fuel materials in three categories: (1) uranium-aluminum billets, (2) uranium-aluminum fuel elements, and (3) uranium metal pieces. The AWCC was a standard instrument supplied to the International Atomic Energy Agency under the International Safeguards Project Office Task A.51. Excellent agreement was obtained between the CRNL measurements and previous Los Alamos National Laboratory measurements on similar mockup fuel material. Calibration curves were obtained for each sample category. 2 refs., 8 figs., 15 tabs.

Krick, M.S.; Menlove, H.O.; Zick, J.; Ikonomou, P.

1985-05-01

355

Uranium in the Savannah River Site environment  

SciTech Connect

The purpose of this report is to consolidate the history of environmental uranium studies conducted by SRS and to describe the status of uranium in the environment. The report is intended to be a living document'' that will be updated periodically. This draft issue, February 1992, documents studies that occurred from 1954 to 1989. Data in this report are taken primarily from annual and semiannual environmental reports for SRS. Semiannual reports were published from 1954 through 1962. Annual reports have been published since 1963. Occasionally unpublished data are included in this report for completeness.

Evans, A.G.; Bauer, L.R.; Haselow, J.S.; Hayes, D.W.; Martin, H.L.; McDowell, W.L.; Pickett, J.B.

1992-12-09

356

Uranium in the Savannah River Site environment  

SciTech Connect

The purpose of this report is to consolidate the history of environmental uranium studies conducted by SRS and to describe the status of uranium in the environment. The report is intended to be a ``living document`` that will be updated periodically. This draft issue, February 1992, documents studies that occurred from 1954 to 1989. Data in this report are taken primarily from annual and semiannual environmental reports for SRS. Semiannual reports were published from 1954 through 1962. Annual reports have been published since 1963. Occasionally unpublished data are included in this report for completeness.

Evans, A.G.; Bauer, L.R.; Haselow, J.S.; Hayes, D.W.; Martin, H.L.; McDowell, W.L.; Pickett, J.B.

1992-12-09

357

Evaporation of Enriched Uranium Solutions Containing Organophosphates  

SciTech Connect

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.

Pierce, R.A.

1999-03-18

358

Pyrophoricity and ignition of bulk uranium metal  

SciTech Connect

Spent N-Reactor fuel will be moved from wet pool storage to dry containerized storage. As part of the safety requirements, it is necessary to understand the ignition characteristics of this fuel to insure safety during processing and storage. A model has therefore been created that calculates the ignition temperature of bulk uranium metal in response to both surface reactions of the uranium metal and associated high energy transients such as burning metal hydrides or hydrogen gas at the surface. This model will be applied to process and storage conditions to predict the ignition temperatures.

Cooper, T.D.; Cramer, E. [Westinghouse Hanford Co., Richland, WA (United States); Thornton, T. [Pacific Northwest Lab., Richland, WA (United States)

1996-12-31

359

Uranium in NIMROC standard igneous rock samples  

NASA Technical Reports Server (NTRS)

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.

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

1976-01-01

360

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

E-print Network

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.

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

2014-09-29

361

National Uranium Resource Evaluation: Joplin Quadrangle, Missouri and Kansas  

SciTech Connect

Reconnaissance and detailed geologic and radiometric investigations were conducted throughout the Joplin Quadrangle, Missouri and Kansas, to evaluate the uranium favorability using National Uranium Resource Evaluation criteria. Surface and subsurface studies were augmented by aerial radiometric surveys and hydrogeochemical and stream-sediment reconnaissance studies. Results of the investigations indicate that black shales of Desmoinesian and Missourian (Pennsylvanian) age are environments favorable for the deposition of uranium. The uranium is concentrated in phosphate nodules within these black shales. Environments considered unfavorable for uranium deposits are fluvial placers, coals, limestones, all sandstones, peridotite, granites, the Pennsylvanian-Mississippian unconformity, and vein-type deposits in sedimentary rocks.

Derby, J.R.; Upshaw, L.P.; Carter, E.O.; Roach, L.F.; Roach, D.G.

1982-08-01

362

Supercritical Fluid Extraction and Separation of Uranium from Other Actinides  

SciTech Connect

This paper investigates the feasibility of separating uranium from other actinides by using supercritical fluid carbon dioxide (sc-CO2) as a solvent modified with tri-n-butylphosphate (TBP) for the development of an extraction and counter current stripping technique, which would be a more efficient and environmentally benign technology for used nuclear fuel reprocessing compared to traditional solvent extraction. Several actinides (U(VI), Np(VI), Pu(IV), and Am(III)) were extracted in sc-CO2 modified with TBP over a range of nitric acid concentrations and then the actinides were exposed to reducing and complexing agents to suppress their extractability. According to this study, the separation of uranium from plutonium in sc-CO2 modified with TBP was successful at nitric acid concentrations of less than 3 M in the presence of acetohydroxamic acid or oxalic acid, and the separation of uranium from neptunium was successful at nitric acid concentrations of less than 1 M in the presence of acetohydroxamic acid, oxalic acid, or sodium nitrite.

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

2014-06-01

363

Uranium azide photolysis results in CH bond activation and provides evidence for a terminal uranium nitride  

Microsoft Academic Search

Uranium nitride [U?N]x is an alternative nuclear fuel that has great potential in the expanding future of nuclear power; however, very little is known about the U?N functionality. We show, for the first time, that a terminal uranium nitride complex can be generated by photolysis of an azide (U-N=N=N) precursor. The transient U?N fragment is reactive and undergoes insertion into

Robert K. Thomson; Thibault Cantat; Brian L. Scott; David E. Morris; Enrique R. Batista; Jaqueline L. Kiplinger

2010-01-01

364

Spectrophotometric determination of uranium in process streams of a uranium extraction plant.  

PubMed

This paper deals with the development and standardization of procedures for the determination of uranium on a routine basis in various process streams of a uranium extraction plant, covering a wide range of concentrations from 350 g 1(-1) down to 5 mg 1(-1) using only a spectrophotometric technique. The self-absorption of uranyl ion in dilute phosphoric acid and the violet-blue colour of the UO(2)(2+)-Arsenazo III complex in 4 M HC1 were exploited for high and low concentrations of uranium, respectively. The methods described were applied to samples of varying nature such as aqueous, organics and solids, involve minimal sample preparation and do not require prior separation of uranium from impurities. The interfering impurities in different process streams were also studied. Large quantities of silica as undissolved material poses a serious interference in the case of UNS and UNF. Considerable quantities of iron in UNS, UNF, UNR and UNRC cause interference. Possible remedies in these cases are suggested. Problems with the direct spectrophotometric measurement of organic samples is discussed. The effect of the presence of large quantities of ammonium nitrate and sodium nitrate in WD samples on the determination of uranium is also discussed. The results are compared with those obtained by volumetry and X-ray fluorescence spectrometry for higher concentrations of uranium and by extraction-spectrophotometry (ethyl acetate-thiocyanate method) for lower concentrations. Relative standard deviation of 1% and 5% for high and low concentrations, respectively, were obtained, which are adequate as far as process stream samples are concerned. The compared results are in fair agreement. The problems associated with the determination of uranium in these process streams are discussed. Experimental results for 10 different process streams normally encountered in a uranium extraction plant are tabulated. PMID:18966745

Murty, B N; Jagannath, Y V; Yadav, R B; Ramamurty, C K; Syamsundar, S

1997-02-01

365

Spectrophotometric determination of uranium in process streams of a uranium extraction plant  

Microsoft Academic Search

This paper deals with the development and standardization of procedures for the determination of uranium on a routine basis in various process streams of a uranium extraction plant, covering a wide range of concentrations from 350 g 1?1 down to 5 mg 1?1 using only a spectrophotometric technique. The self-absorption of uranyl ion in dilute phosphoric acid and the violet-blue

B. Narasimha Murty; Y. V. S. Jagannath; R. B. Yadav; C. K. Ramamurty; S. Syamsundar

1997-01-01

366

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

SciTech Connect

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.

NONE

1995-07-05

367

Extractive electrospray ionization mass spectrometry for uranium chemistry studies.  

PubMed

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

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

2013-01-01

368

Extractive Electrospray Ionization Mass Spectrometry for Uranium Chemistry Studies  

PubMed Central

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

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

2013-01-01

369

Enhanced uranium immobilization and reduction by Geobacter sulfurreducens biofilms.  

PubMed

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

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

2014-11-01

370

Pyrophoricity of uranium in long-term storage environments  

SciTech Connect

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.

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

1994-01-01

371

Spectrophotometric determination of micro amounts of uranium.  

PubMed

Uranium(VI) in the presence of numerous cations and anions is determined by the iron(II)-phosphoric acid-Ferrozine method at concentrations of 8-75,mug/25 ml with a relative precision of 3-1%. PMID:18962396

Hseih, J Y; Jaselskis, B

1979-02-01

372

Uranium-series dating of antarctic ice  

SciTech Connect

It is very interesting to date polar ice radiometrically. Bands of dust imbedded in ice are frequently observed in antarctic ice fields. This work focuses on dating ice samples with high dust contents by the uranium-series method. The author obtained uranium-series ages of 325 thousand (+/- 75) and 100 thousand (+/- 20) years for dusty ice samples from two sites in the main Allan Hills ice field. The dust-banded ice was collected from 50- to 100-centimeter depth at two sites, called Cul de Sac 100 and Cul de Sac 150. The particles in these samples were examined with an optical microscope and found to consist essentially (more than 95% of the particulates) of fine volcanic glass shards full of vesicles and microvesicles. Evidently the fine volcanic glass shards were deposited on snow, became incorporated in the ice, and moved with the ice to the Allan Hills sites. Ice samples with other types of particulates, such as terrestrial morraine, may also be amenable to uranium-series dating; however, it is difficult to date ice with less than 0.03 gram of fine particulates per kilogram of ice with their present technique. The uranium-series method can cover the age range from 10,000 to 600,000 years.

Fireman, E.L.

1986-01-01

373

The multiphoton ionization of uranium hexafluoride  

SciTech Connect

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.

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

1992-05-01

374

Characterisation of projectiles composed of depleted uranium  

Microsoft Academic Search

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

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

375

The hazard posed by depleted uranium munitions  

Microsoft Academic Search

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

Steve Fetter; Frank N. von Hippel

2000-01-01

376

Semiconductor neutron detectors using depleted uranium oxide  

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

377

Processing depleted uranium quad alloy penetrator rods  

Microsoft Academic Search

Two depleted uranium (DU) quad alloys were cast, extruded and rolled to produce penetrator rods. The two alloy combinations were (1) 1 wt % molybdenum (Mo), 1 wt % niobium (Nb), and 0.75 wt % titanium (Ti); and (2) 1 wt % tantalum (Ta), 1 wt % Nb, and 0.75 wt % Ti. This report covers the processing and results

Bokan

1987-01-01

378

URANIUM MINING TENORM TECHNICAL REPORT - VOLUME I  

EPA Science Inventory

The intent of this effort is to publish a series of individual reports, using a consistent approach, on industries that makes use of or produces TENORM waste. The first three products of this effort will be a URANIUM MINE LOCATION DATABASE, included in the Science Inventory as a...

379

Geodatabase of the South Texas Uranium District  

Microsoft Academic Search

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

Mark Beaman; William Wade McGee

380

THE CORROSION BEHAVIORS OF PLUTONIUM AND URANIUM  

Microsoft Academic Search

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.

Waber

1958-01-01

381

Statistical design of a uranium corrosion experiment  

SciTech Connect

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.

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

2009-01-01

382

Phosphate Barriers for Immobilization of Uranium Plumes  

SciTech Connect

Uranium contamination of the subsurface remains a persistent problem plaguing remedial design at sites across the U.S. that were involved with production, handling, storage, milling, and reprocessing of uranium for both civilian and defense related purposes. Remediation efforts to date have relied upon excavation, pump-and-treat, or passive remediation barriers (PRB?s) to remove or attenuate uranium mobility. Documented cases convincingly demonstrate that excavation and pump-and-treat methods are ineffective for a number of highly contaminated sites. There is growing concern that use of conventional PRB?s, such as zero-valent iron, may be a temporary solution to a problem that will persist for thousands of years. Alternatives to the standard treatment methods are therefore warranted. The core objective of our research is to demonstrate that a phosphorus amendment strategy will result in a reduction of dissolved uranium to below the proposed drinking water standard. Our hypothesis is that long-chain sodium polyphosphate compounds forestall precipitation of sparingly soluble uranyl phosphate compounds, which is paramount to preventing fouling of wells at the point of injection.

Burns, Peter C.

2004-12-01

383

Radiological health aspects of uranium milling  

SciTech Connect

This report describes the operation of conventional and unconventional uranium milling processes, the potential for occupational exposure to ionizing radiation at the mill, methods for radiological safety, methods of evaluating occupational radiation exposures, and current government regulations for protecting workers and ensuring that standards for radiation protection are adhered to. In addition, a survey of current radiological health practices is summarized.

Fisher, D.R.; Stoetzel, G.A.

1983-05-01

384

National Uranium Resource Evaluation: Marfa Quadrangle, Texas  

SciTech Connect

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.

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

1982-09-01

385

Restoration of uranium solution mining deposits  

SciTech Connect

A process is provided for restoring an ore deposit after uranium solution mining using ammonium carbonate leaching solutions has ceased. The process involves flushing the deposit with an aqueous solution of a potassium salt during which potassium ions exchange with ammonium ions remaining in the deposit. The ammonium containing flushing solution is withdrawn from the deposit for disposal.

Devries, F.W.; Lawes, B.C.

1982-01-19

386

Subcritical Neutron Amplifier Based on Enriched Uranium  

Microsoft Academic Search

The present work is devoted to an investigation of the properties of a subcritical system consisting of enriched uranium, an amplifier of a neutron flux from an external source, and a power amplifier, depending on the composition of the system and the energy of the neutrons from the source [1?3]. The geometric size of the assembly was determined from the

V. A. Babenko; L. L. Enkovskii; V. N. Pavlovich; E. A. Pupirina

2002-01-01

387

Production of uranium ore in capitalist countries  

Microsoft Academic Search

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

N. I. Chesnokov; V. G. Ivanov

1973-01-01

388

Thermophysical properties of gas phase uranium tetrafluoride  

NASA Technical Reports Server (NTRS)

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.

Watanabe, Yoichi; Anghaie, Samim

1993-01-01

389

The Quest for the Heaviest Uranium Isotope  

E-print Network

We study Uranium isotopes and surrounding elements at very large neutron number excess. Relativistic mean field and Skyrme-type approaches with different parametrizations are used in the study. Most models show clear indications for isotopes that are stable with respect to neutron emission far beyond N=184 up to the range of around N=258.

S. Schramm; D. Gridnev; D. V. Tarasov; V. N. Tarasov; W. Greiner

2012-01-17

390

Uranium on the Checkerboard: Crisis at Crownpoint  

ERIC Educational Resources Information Center

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)

Barry, Tom; Wood, Beth

1978-01-01

391

Radiological aspects of in situ uranium recovery  

SciTech Connect

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)

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

2007-07-01

392

Uranium dynamics and developmental sensitivity in rat kidney.  

PubMed

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

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

393

Uranium Sequestration by Aluminum Phosphate Minerals in Unsaturated Soils  

SciTech Connect

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)

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

2007-07-01

394

RECALIBRATION OF H CANYON ONLINE SPECTROPHOTOMETER AT EXTENDED URANIUM CONCENTRATION  

SciTech Connect

The H Canyon online spectrophotometers are calibrated for measurement of the uranium and nitric acid concentrations of several tanks in the 2nd Uranium Cycle.[1] The spectrometers, flow cells, and prediction models are currently optimized for a process in which uranium concentrations are expected to range from 0-15 g/L and nitric acid concentrations from 0.05-6 M. However, an upcoming processing campaign will involve 'Super Kukla' material, which has a lower than usual enrichment of fissionable uranium. Total uranium concentrations will be higher, spanning approximately 0-30 g/L U, with no change in the nitric acid concentrations. The new processing conditions require the installation of new flow cells with shorter path lengths. As the process solutions have a higher uranium concentration, the shorter path length is required to decrease the absorptivity to values closer to the optimal range for the instrument. Also, new uranium and nitric acid prediction models are required to span the extended uranium concentration range. The models will be developed for the 17.5 and 15.4 tanks, for which nitric acid concentrations will not exceed 1 M. The restricted acid range compared to the original models is anticipated to reduce the measurement uncertainty for both uranium and nitric acid. The online spectrophotometers in H Canyon Second Uranium Cycle were modified to allow measurement of uranium and nitric acid for the Super Kukla processing campaign. The expected uranium concentrations, which are higher than those that have been recently processed, required new flow cells with one-third the optical path length of the existing cells. Also, new uranium and nitric acid calibrations were made. The estimated reading uncertainties (2{sigma}) for Tanks 15.4 and 17.5 are {approx}5% for uranium and {approx}25% for nitric acid.

Lascola, R

2008-10-29

395

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

SciTech Connect

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)

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

396

A simple method for determination of natural and depleted uranium in surface soil samples.  

PubMed

A simple and efficient method for determination of uranium content in surface soil samples contaminated with depleted uranium, by gamma ray spectrometry is presented. The content of natural uranium and depleted uranium, as well as the activity ratio (235)U/(238)U of depleted uranium, were determined in contaminated surface soil samples by application of this method. PMID:20022756

Vukanac, I; Novkovi?, D; Kandi?, A; Djurasevi?, M; Milosevi?, Z

2010-01-01

397

DYNAMIC PROPERTIES OF SHOCK LOADED THIN URANIUM FOILS  

SciTech Connect

A series of spall experiments has been completed with thin depleted uranium targets, nominally 0.1 mm thick. The first set of uranium spall targets was cut and ground to final thickness from electro-refined, high-purity, cast uranium. The second set was rolled to final thickness from low purity uranium. The impactors for these experiments were laser-launched 0.05-mm thick copper flyers, 3 mm in diameter. Laser energies were varied to yield a range of flyer impact velocities. This resulted in varying degrees of damage to the uranium spall targets, from deformation to complete spall or separation at the higher velocities. Dynamic measurements of the uranium target free surface velocities were obtained with dual velocity interferometers. Uranium targets were recovered and sectioned after testing. Free surface velocity profiles were similar for the two types of uranium, but spall strengths (estimated from the magnitude of the pull-back signal) are higher for the high-purity cast uranium. Velocity profiles and microstructural evidence of spall from the sectioned uranium targets are presented.

Robbins, D. L. (David L.); Kelly, A. M. (Anna Marie); Alexander, D. J. (David J.); Hanrahan, R. J. (Robert J.); Snow, R. C. (Ronny C.); Gehr, R. J. (Russell J.); Rupp, Ted Dean,; Sheffield, S. A. (Stephen A.); Stahl, D. B. (David B.)

2001-01-01

398

Dynamic Properties of Shock Loaded Thin Uranium Foils  

NASA Astrophysics Data System (ADS)

A series of spall experiments has been completed with thin depleted uranium targets, nominally 0.1 mm thick. The first set of uranium spall targets was cut and ground to final thickness from electro-refined, high-purity, cast uranium. The second set was rolled to final thickness from low purity uranium. The impactors for these experiments were laser-launched 0.05-mm thick copper flyers, 3 mm in diameter. Laser energies were varied to yield a range of flyer impact velocities. This resulted in varying degrees of damage to the uranium targets, from deformation to complete spall or separation at the higher velocities. Dynamic measurements of the uranium target free surface velocities were obtained with dual velocity interferometers. Uranium targets were recovered and sectioned after testing. Free surface velocity profiles were similar for the two types of uranium, but spall strengths (estimated from the magnitude of the pull-back signal) are higher for the high-purity cast uranium. Velocity profiles and microstructural evidence of spall from the sectioned uranium targets are presented.

Robbins, David L.; Kelly, Ann M.; Alexander, David J.; Hanrahan, Robert J.; Snow, Ronny C.; Gehr, Russell J.; Rupp, Ted D.; Sheffield, Stephen A.; Stahl, David B.

2002-07-01

399

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

USGS Publications Warehouse

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.

Finch, Warren Irvin

1996-01-01

400

Determining uranium speciation in contaminated soils by molecular spectroscopic methods: Examples from the Uranium in Soils Integrated Demonstration  

SciTech Connect

The US Department of Energy`s former uranium production facility located at Fernald, OH (18 mi NW of Cincinnati) is the host site for an Integrated Demonstration for remediation of uranium-contaminated soils. A wide variety of source terms for uranium contamination have been identified reflecting the diversity of operations at the facility. Most of the uranium contamination is contained in the top {approximately}1/2 m of soil, but uranium has been found in perched waters indicating substantial migration. In support of the development of remediation technologies and risk assessment, we are conducting uranium speciation studies on untreated and treated soils using molecular spectroscopies. Untreated soils from five discrete sites have been analyzed. We have found that {approximately}80--90% of the uranium exists as hexavalent UO{sub 2}{sup 2+} species even though many source terms consisted of tetravalent uranium species such as UO{sub 2}. Much of the uranium exists as microcrystalline precipitates (secondary minerals). There is also clear evidence for variations in uranium species from the microscopic to the macroscopic scale. However, similarities in speciation at sites having different source terms suggest that soil and groundwater chemistry may be as important as source term in defining the uranium speciation in these soils. Characterization of treated soils has focused on materials from two sites that have undergone leaching using conventional extractants (e.g., carbonate, citrate) or novel chelators such as Tiron. Redox reagents have also been used to facilitate the leaching process. Three different classes of treated soils have been identified based on the speciation of uranium remaining in the soils. In general, the effective treatments decrease the total uranium while increasing the ratio of U(IV) to U(VI) species.

Allen, P.G.; Berg, J.M.; Chisholm-Brause, C.J.; Conradson, S.D.; Donohoe, R.J.; Morris, D.E.; Musgrave, J.A.; Tait, C.D.

1994-03-01

401

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

SciTech Connect

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)

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

2012-07-01

402

Assessment of Preferred Depleted Uranium Disposal Forms  

SciTech Connect

The Department of Energy (DOE) is in the process of converting about 700,000 metric tons (MT) of depleted uranium hexafluoride (DUF6) containing 475,000 MT of depleted uranium (DU) to a stable form more suitable for long-term storage or disposal. Potential conversion forms include the tetrafluoride (DUF4), oxide (DUO2 or DU3O8), or metal. If worthwhile beneficial uses cannot be found for the DU product form, it will be sent to an appropriate site for disposal. The DU products are considered to be low-level waste (LLW) under both DOE orders and Nuclear Regulatory Commission (NRC) regulations. The objective of this study was to assess the acceptability of the potential DU conversion products at potential LLW disposal sites to provide a basis for DOE decisions on the preferred DU product form and a path forward that will ensure reliable and efficient disposal.

Croff, A.G.; Hightower, J.R.; Lee, D.W.; Michaels, G.E.; Ranek, N.L.; Trabalka, J.R.

2000-06-01

403

Uranium enrichment management review: summary of analysis  

SciTech Connect

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.

Not Available

1981-01-01

404

National Uranium Resource Evaluation: Presido Quadrangle, Texas  

SciTech Connect

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.

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

1982-09-01

405

Uranium series dating of Allan Hills ice  

NASA Technical Reports Server (NTRS)

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.

Fireman, E. L.

1986-01-01

406

Reductive dissolution approaches to removal of uranium from contaminated soils  

SciTech Connect

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.

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

1994-06-01

407

National Uranium Resource Evaluation: Walker Lake Quadrangle, California and Nevada  

SciTech Connect

The Miocene Relief Peak Formation occurs in the Sierra Nevada, where it consists mainly of andesitic flows, autobrecciated flows, and mudflows. However, fluviatile rocks are common in the lower part of the formation. They contain abundant carbonaceous material, are commonly permeable, and are interbedded with less permeable rocks. The Juniper mine, the principal uranium occurrence in the fluviatile rocks, reportedly has produced more than 20 tons of U/sub 3/O/sub 8/. Although rocks of the Relief Peak Formation lack aerial radiometric uranium anomalies and generally have only average uranium content away from uranium occurrences, the fluviatile rocks of the formation are considered favorable for uranium deposits because of their lithologic characteristics and uranium occurrences. Some areas of Tertiary sedimentary rocks presently are categorized as unfavorable for the required minimum endowment. They have some geologically favorable characteristics, however, as well as indications of industry exploration activities, and they may prove to be favorable as more information becomes available.

Durham, D.L.; Felmlee, J.K.

1982-09-01

408

In-line assay monitor for uranium hexafluoride  

DOEpatents

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.

Wallace, S.A.

1980-03-21

409

The uranium cylinder assay system for enrichment plant safeguards  

SciTech Connect

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.

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

410

Recovery of uranium from seawater by immobilized tannin  

SciTech Connect

Tannin compounds having multiple adjacent hydroxy groups have an extremely high affinity for uranium. To prevent the leaching of tannins into water and to improve the adsorbing characteristics of these compounds, the authors tried to immobilize tannins. The immobilized tannin has the most favorable features for uranium recovery; high selective adsorption ability to uranium, rapid adsorption rate, and applicability in both column and batch systems. The immobilized tannin can recover uranium from natural seawater with high efficiency. About 2530 ..mu..g uranium is adsorbed per gram of this adsorbent within 22 h. Depending on the concentration in seawater, an enrichment of up to 766,000-fold within the adsorbent is possible. Almost all uranium adsorbed is easily desorbed with a very dilute acid. Thus, the immobilized tannin can be used repeatedly in the adsorption-desorption process.

Sakaguchi, T.; Nakajima, A.

1987-06-01

411

Measurements of uranium mass confined in high density plasmas  

NASA Technical Reports Server (NTRS)

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.

Stoeffler, R. C.

1976-01-01

412

Thermal stabilization of uranium mill tailings  

Microsoft Academic Search

The treatment of uranium mill tailings by high-temperature sintering (>1050°C) has been investigated as a means of controlling the release of ²²²Rn and leachable contaminants. Thermal stabilization in laboratory trials at 1200°C reduced the radon emanation of various tailings by factors ranging from 37 to 1400 depending on the mineralogy of the tailings. The leachability of most contaminants (e.g., Al,

David R. Dreesen; Edward J. Cokal; Lawrence E. Wangen; Joel M. Williams; Edward F. Thode

1984-01-01

413

Engineering assessment of inactive uranium mill tailings  

SciTech Connect

The Grand Junction site has been reevaluated in order to revise the October 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Grand Junction, Colorado. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 1.9 million tons of tailings at the Grand Junction site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation are also factors. The eight alternative actions presented herein range from millsite and off-site decontamination with the addition of 3 m of stabilization cover material (Option I), to removal of the tailings to remote disposal sites and decontamination of the tailings site (Options II through VIII). Cost estimates for the eight options range from about $10,200,000 for stabilization in-place to about $39,500,000 for disposal in the DeBeque area, at a distance of about 35 mi, using transportation by rail. If transportation to DeBeque were by truck, the cost estimated to be about $41,900,000. Three principal alternatives for the reprocessing of the Grand Junction tailings were examined: (a) heap leaching; (b) treatment at an existing mill; and (c) reprocessing at a new conventional mill constructed for tailings reprocessing. The cost of the uranium recovered would be about $200/lb by heap leach and $150/lb by conventional plant processes. The spot market price for uranium was $25/lb early in 1981. Therefore, reprocessing the tailings for uranium recovery appears not to be economically attractive.

Not Available

1981-07-01

414

Spectrophotometric determination of uranium in nuclear waste  

Microsoft Academic Search

A spectrophotometric method for determining uranium in nuclear waste was developed using 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (bromo-PADAP). By extracting the color into Aliquat-336 it was possible to accurately measure U at the 1 ..mu..g level. No significant interferences were observed from 34 interfering ions when a tri-n-octylphosphine oxide (TOPO) pre-extraction of U was used. The effect of pH, color development time, bromo-PADAP concentration,

Winters

1976-01-01

415

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

E-print Network

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.

Germano D'Abramo

2003-06-05

416

Texture in ZIRCALOY-clad uranium  

Microsoft Academic Search

An enriched (30%²³⁵U) uranium target is being fabricated for the ANL spallation neutron source (IPNS). They have measured the orientation distribution of neutron diffraction intensities (texture) of test casting made of depleted ²³⁸U. Their results indicate the presence of large grains which may swell anisotropically with radiation damage and produce a separation of the ZIRCALOY protective cladding from the surface

F. Ross; D. Reichel; A. Krawitz; M. Mueller; J. Richardson

2009-01-01

417

Uranium enrichment export control guide: Gaseous diffusion  

SciTech Connect

This document was prepared to serve as a guide for export control officials in their interpretation, understanding, and implementation of export laws that relate to the Zangger International Trigger List for gaseous diffusion uranium enrichment process components, equipment, and materials. Particular emphasis is focused on items that are especially designed or prepared since export controls are required for these by States that are party to the International Nuclear Nonproliferation Treaty.

Not Available

1989-09-01

418

Phosphate Barriers for Immobilization of Uranium Plumes  

SciTech Connect

Uranium contamination of the subsurface has remained a persistent problem plaguing remedial design at sites across the U.S. that were involved with production, handling, storage, milling, and reprocessing of fissile uranium for both civilian and defense related purposes. Remediation efforts to date have relied upon excavation, pump-and-treat, or passive remediation barriers (PRB?s) to remove or attenuate uranium mobility. Documented cases convincingly demonstrate that excavation and pump-and-treat methods are ineffective for a number of highly contaminated sites. There is growing concern that use of conventional PRB?s, such as zero-valent iron, are a temporary solution to a problem that will persist for thousands of years. Alternatives to the standard treatment methods are therefore warranted. The core objective of our research is to demonstrate that a phosphorous amendment strategy will result in a reduction of dissolved uranium to below the proposed drinking water standard. Our hypothesis is that long-chain polyphosphate compounds forestall precipitation of sparingly soluble uranyl phosphate compounds, which is key to preventing fouling of wells at the point of injection. Our other fundamental objective is to synthesize and correctly characterize the uranyl phosphate phases that form in the geochemical conditions under consideration. This report summarizes work conducted at the University of Notre Dame through November of 2003 under DOE grant DE-FG07-02ER63489, which has been funded since September, 2002. The objectives at Notre Dame are development of synthesis techniques for uranyl phosphate phases, together with detailed structural and chemical characterization of the myriad of uranyl phosphate phases that may form under geochemical conditions under consideration.

Burns, Peter C.

2005-06-01

419

Energy balance for uranium recovery from seawater  

SciTech Connect

The energy return on investment (EROI) of an energy resource is the ratio of the energy it ultimately produces to the energy used to recover it. EROI is a key viability measure for a new recovery technology, particularly in its early stages of development when financial cost assessment would be premature or highly uncertain. This paper estimates the EROI of uranium recovery from seawater via a braid adsorbent technology. In this paper, the energy cost of obtaining uranium from seawater is assessed by breaking the production chain into three processes: adsorbent production, adsorbent deployment and mooring, and uranium elution and purification. Both direct and embodied energy inputs are considered. Direct energy is the energy used by the processes themselves, while embodied energy is used to fabricate their material, equipment or chemical inputs. If the uranium is used in a once-through fuel cycle, the braid adsorbent technology EROI ranges from 12 to 27, depending on still-uncertain performance and system design parameters. It is highly sensitive to the adsorbent capacity in grams of U captured per kg of adsorbent as well as to potential economies in chemical use. This compares to an EROI of ca. 300 for contemporary terrestrial mining. It is important to note that these figures only consider the mineral extraction step in the fuel cycle. At a reference performance level of 2.76 g U recovered per kg adsorbent immersed, the largest energy consumers are the chemicals used in adsorbent production (63%), anchor chain mooring system fabrication and operations (17%), and unit processes in the adsorbent production step (12%). (authors)

Schneider, E.; Lindner, H. [The University of Texas, 1 University Station C2200, Austin, TX 78712 (United States)

2013-07-01

420

Biosorption of uranium on Sargassum biomass  

Microsoft Academic Search

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

Jinbai Yang; Bohumil Volesky

1999-01-01

421

78 FR 17450 - Notice of Issuance of Materials License Renewal, Operating License SUA-1341, Uranium One USA, Inc...  

Federal Register 2010, 2011, 2012, 2013

...License Renewal, Operating License SUA-1341, Uranium One USA, Inc., Willow Creek Uranium In Situ Recovery Project AGENCY: Nuclear Regulatory...renewal for Materials License No. SUA- 1341 to Uranium One USA, Inc. (Uranium One) for its...

2013-03-21

422

75 FR 62153 - Notice of the Nuclear Regulatory Commission Issuance of Materials License SUA-1596 for Uranium...  

Federal Register 2010, 2011, 2012, 2013

...Commission Issuance of Materials License SUA-1596 for Uranium One Americas, Inc. Moore Ranch In Situ Recovery...Regulatory Commission (NRC) has issued a license to Uranium One Americas, Inc. (Uranium One) for its Moore Ranch uranium in situ...

2010-10-07

423

Health concerns in uranium mining and milling  

SciTech Connect

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.

Archer, V.E.

1981-07-01

424

Spectrophotometric determination of uranium using dibenzoylmethane  

SciTech Connect

A procedure for the spectrophotometric determination of uranium has been developed in support of minerals research being conducted by the Bureau of Mines. Uranium is separated from the sample by tributylphosphate extraction from acid solution containing added aluminum nitrate and (ethylene dinitrilo)-tetraacetic acid solutions. The colored uranium-dibenzoylmethane complex is developed in the organic phase by adding an ethanol solution of dibenzoylmethane buffered with triethanolamine. Absorbance is measured at 410 nanometers, and the response is linear up to at least 100 micrograms U/sub 3/O/sub 8/ in the aqueous aliquot taken for analysis. Aliquots containing as little as 8 micrograms U/sub 3/O/sub 8/ may be analyzed with relative errors no greater than +-5%. For aliquots containing at least 35 micrograms U/sub 3/O/sub 8/, relative standard deviation at the 95% confidence level is about +-2.2%. Appropriate procedures are given for analyzing a wide variety of samples.

Jones, M.M.; MacDuff, J.S.; Whitehead, A.B.

1980-01-01

425

Uranium concentration monitor manual: 2300 system  

SciTech Connect

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.

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

1985-04-01

426

Critical analysis of world uranium resources  

USGS Publications Warehouse

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

Hall, Susan; Coleman, Margaret

2013-01-01

427

Determination of uranium in natural waters  

USGS Publications Warehouse

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.

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

1965-01-01

428

Uranium diphosphonates templated by interlayer organic amines  

NASA Astrophysics Data System (ADS)

The hydrothermal treatment of uranium trioxide and methylenediphosphonic acid with a variety of amines (2,2-dipyridyl, triethylenediamine, ethylenediamine, and 1,10-phenanthroline) at 200 °C results in the crystallization of a series of layered uranium diphosphonate compounds, [C10H9N2]{UO2(H2O)[CH2(PO3)(PO3H)]} (Ubip2), [C6H14N2]{(UO2)2[CH2(PO3)(PO3H)]2·2H2O} (UDAB), [C2H10N2]2{(UO2)2(H2O)2[CH2(PO3)2]2·0.5H2O} (Uethyl), and [C12H9N2]{UO2(H2O)[CH2(PO3)(PO3H)]} (Uphen). The crystal structures of the compounds are based on UO7 units linked by methylenediphosphonate molecules to form two-dimensional anionic sheets in Ubip2 and UDAB, and one-dimensional anionic chains in Uethyl and Uphen, which are charge balanced by protonated amine molecules. Interaction of the amine molecules with phosphonate oxygens and water molecules results in extensive hydrogen bonding in the interlayer. These amine molecules serve both as structure-directing agents and charge-balancing cations for the anionic uranium phosphonate sheets and chains in the formation of the different coordination geometries and topologies of each structure. Reported herein are the syntheses, structural and spectroscopic characterization of the synthesized compounds.

Nelson, Anna-Gay D.; Alekseev, Evgeny V.; Albrecht-Schmitt, Thomas E.; Ewing, Rodney C.

2013-02-01

429

United States Transuranium and Uranium Registries  

SciTech Connect

The United States Transuranium and Uranium Registries are unique human tissue research programs studying the distribution, dose, and possible biological effects of the actinide elements in man, with the primary goal of assuring the adequacy of radiation protection standards for these radionuclides. The Registries research is based on radiochemical analysis of tissues collected at autopsy from voluntary donors who have documented occupational exposure to the actinides. To date, tissues, or in some cases radioanalytical results only, have been obtained from approximately 300 individuals; another 464 living individuals have volunteered to participate in the Registries research programs and have signed premortem informed consent and autopsy permissions. The Registries originated at the National Plutonium Registry which was started in 1968 as a then Atomic Energy Commission project under the aegis of a prime contractor at the Hanford site. In 1970, the name was changed to the United States Transuranium Registry to reflect a broader involvement with the higher actinides. In 1978, an administratively separate parallel registry, the United States Uranium Registry, was formed to carry out similar studies among uranium fuel cycle workers.

Kathren, R.

1993-02-28

430

X-Ray Emission from "Uranium" Stars  

NASA Technical Reports Server (NTRS)

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.

Schlegel, Eric; Mushotzky, Richard (Technical Monitor)

2005-01-01

431

Tables des principaux minerais d'uranium et de thorium  

E-print Network

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

Paris-Sud XI, Université de

432

Multisyringe flow injection spectrophotometric determination of uranium in water samples  

Microsoft Academic Search

A multisyringe flow injection analysis method for the determination of uranium in water samples was developed. The methodology\\u000a was based on the complexation reaction of uranium with arsenazo (III) at pH 2.0. Uranium concentrations were spectrophotometrically\\u000a detected at 649 nm using a light emitting diode. Under the optimized conditions, a linear dynamic range from 0.1 to 4.0 ?g mL?1, a 3? detection limit

Jorge L. Guzmán Mar; Leticia López Martínez; Pedro L. López de Alba; Nancy Ornelas Soto; Víctor Cerdà Martín

2009-01-01

433

Extraction and spectrophotometric determination of uranium in phosphate fertilizers  

Microsoft Academic Search

An extraction and spectrophotometric method for determination of trace amounts of uranium in phosphate fertilizers is described. It is based on the extraction of uranium with trioctylphosphine oxide in benzene and the spectrophotometric determination of uranium with Arsenazo III in buffer-alcoholic medium. The maximum absorbance occurs at 655 nm with a molar absorptivity of 1.2·104 l·mol–1·cm–1. Beer's law is obeyed

N. Vu?i?; Z. Ili?

1989-01-01

434

Speciation and spectrophotometric determination of uranium in seawater  

Microsoft Academic Search

A series of ion-exchange and extraction procedures for the separation of uranium from seawater samples and subsequent spectrophotometric determination of uranium in seawater by means of arsenazo(III) is described. According to the measurements performed by means of traced samples at every stage of separation, the yield of the pre-analytical procedures is generally over 90% and the separation of uranium very

M. KONSTANTINOU; I. PASHALIDIS

435

Thermodynamic properties of uranium in Ga-In based alloys  

NASA Astrophysics Data System (ADS)

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.

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

2013-07-01

436

Microbially Assisted Leaching of Uranium—A Review  

Microsoft Academic Search

Due to depletion of high-grade deposits of uranium and generation of large quantities of tailings produced by mining and metallurgical activities, there is a need to find an economical way to recover uranium from low-grade deposits and secondary resources. Bioleaching of uranium from the ores, minerals and wastes in heap and dumps, besides in-situ biodissolution processes, is rapidly expanding globally,

Abhilash Pillai; B. D. Pandey

2011-01-01

437

Chemical aspects of uranium behavior in soils: A review  

Microsoft Academic Search

Uranium has varying degrees of oxidation (+4 and +6) and is responsive to changes in the redox potential of the environment.\\u000a It is deposited at the reduction barrier with the participation of biota and at the sorption barrier under oxidative conditions.\\u000a Iron (hydr)oxides are the strongest sorbents of uranium. Uranium, being an element of medium biological absorption, can accumulate\\u000a (relative

Yu. N. Vodyanitskii; Dokuchaev Soil

2011-01-01

438

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

E-print Network

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

Paris-Sud XI, Université de

439

The Navajo Uranium Mining Experience, 2003-1952  

NSDL National Science Digital Library

This bibliography, compiled by the Southwest Research and Information Center, contains resources related to Navajo uranium issues and communities affected by uranium mining impacts since the mid-1970s. Entries were selected for their relevancy to Navajo community concerns, Navajo Nation policies, and health and environmental effects of uranium development on Navajo lands. Topics for resources include articles, books, policy statements, reports, presentations, testimony, and published medical, scientific and sociological literature.

Chris Shuey

440

40 CFR 421.320 - Applicability: Description of the secondary uranium subcategory.  

Code of Federal Regulations, 2012 CFR

...Applicability: Description of the secondary uranium subcategory. 421.320 Section...POINT SOURCE CATEGORY Secondary Uranium Subcategory § 421.320 Applicability: Description of the secondary uranium subcategory. The provisions...

2012-07-01

441

76 FR 70170 - Proposed Alternative Soils Standards for the Uravan, Colorado Uranium Mill  

Federal Register 2010, 2011, 2012, 2013

...Soils Standards for the Uravan, Colorado Uranium Mill AGENCY: Nuclear Regulatory Commission. ACTION: Uranium milling alternative standards...specifically amend their Agreements to regulate uranium mill tailings (11e.(2)...

2011-11-10

442

10 CFR 140.13b - Amount of liability insurance required for uranium enrichment facilities.  

Code of Federal Regulations, 2010 CFR

...Amount of liability insurance required for uranium enrichment facilities. 140.13b ...Amount of liability insurance required for uranium enrichment facilities. Each holder...under Parts 40 or 70 of this chapter for a uranium enrichment facility that...

2010-01-01

443

28 CFR 79.52 - Criteria for eligibility for claims by uranium millers.  

...Criteria for eligibility for claims by uranium millers. 79.52 Section 79.52... Eligibility Criteria for Claims by Uranium Millers § 79.52 Criteria for eligibility for claims by uranium millers. To establish...

2014-07-01

444

10 CFR 40.66 - Requirements for advance notice of export shipments of natural uranium.  

Code of Federal Regulations, 2013 CFR

...advance notice of export shipments of natural uranium. 40.66 Section 40.66 Energy...advance notice of export shipments of natural uranium. (a) Each licensee authorized to export natural uranium, other than in the form of ore...

2013-01-01

445

49 CFR 173.420 - Uranium hexafluoride (fissile, fissile excepted and non-fissile).  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Uranium hexafluoride (fissile, fissile excepted...Radioactive) Materials § 173.420 Uranium hexafluoride (fissile, fissile excepted...fissile, fissile excepted or non-fissile uranium hexafluoride must be offered for...

2012-10-01

446

75 FR 44817 - Notice of Availability of Uranium Enrichment Fuel Cycle Facility Inspection Reports Regarding...  

Federal Register 2010, 2011, 2012, 2013

...NRC-2010-0264] Notice of Availability of Uranium Enrichment Fuel Cycle Facility Inspection...CONTACT: Ty Naquin, Project Manager, Uranium Enrichment Branch, Division of Fuel Cycle...1954, as amended. The introduction of uranium hexafluoride into any module of the...

2010-07-29

447

77 FR 1059 - Low Enriched Uranium From France: Initiation of Antidumping Duty Changed Circumstances Review  

Federal Register 2010, 2011, 2012, 2013

...Administration [A-427-818] Low Enriched Uranium From France: Initiation of Antidumping...antidumping duty order on low enriched uranium (LEU) from France with respect to Eurodif...See Letter from AREVA, ``Low Enriched Uranium from France,'' dated December...

2012-01-09

448

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

Code of Federal Regulations, 2013 CFR

...false Applicability; description of the uranium, radium and vanadium ores subcategory...MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium Ores Subcategory...30 Applicability; description of the uranium, radium and vanadium ores...

2013-07-01

449

77 FR 53236 - Proposed International Isotopes Fluorine Extraction Process and Depleted Uranium Deconversion...  

Federal Register 2010, 2011, 2012, 2013

...Fluorine Extraction Process and Depleted Uranium Deconversion Plant in Lea County, New...Fluorine Extraction Process and Depleted Uranium Deconversion Plant (INIS) in Lea County...of a fluorine extraction and depleted uranium deconversion facility (the...

2012-08-31

450

77 FR 18272 - Uranium Enrichment Fuel Cycle Facility Inspection Reports Regarding Louisiana Energy Services LLC...  

Federal Register 2010, 2011, 2012, 2013

...Docket No. 70-3103; NRC-2010-0264] Uranium Enrichment Fuel Cycle Facility Inspection...1954, as amended. The introduction of uranium hexafluoride into any module of the...Commission. Brian W. Smith, Chief, Uranium Enrichment Branch, Division of Fuel...

2012-03-27

451

10 CFR 140.13b - Amount of liability insurance required for uranium enrichment facilities.  

...Amount of liability insurance required for uranium enrichment facilities. 140.13b ...Amount of liability insurance required for uranium enrichment facilities. Each holder...under Parts 40 or 70 of this chapter for a uranium enrichment facility that...

2014-01-01

452

10 CFR 140.13b - Amount of liability insurance required for uranium enrichment facilities.  

Code of Federal Regulations, 2011 CFR

...Amount of liability insurance required for uranium enrichment facilities. 140.13b ...Amount of liability insurance required for uranium enrichment facilities. Each holder...under Parts 40 or 70 of this chapter for a uranium enrichment facility that...

2011-01-01

453

10 CFR 40.33 - Issuance of a license for a uranium enrichment facility.  

... false Issuance of a license for a uranium enrichment facility. 40.33 Section...40.33 Issuance of a license for a uranium enrichment facility. (a) The...of the construction and operation of a uranium enrichment facility. The...

2014-01-01

454

78 FR 66898 - Low Enriched Uranium From France: Final Results of Changed Circumstances Review  

Federal Register 2010, 2011, 2012, 2013

...Administration [A-427-818] Low Enriched Uranium From France: Final Results of Changed...of one specified entry of low enriched uranium (LEU) that entered under a narrow provision...1\\ See Low Enriched Uranium from France: Initiation of...

2013-11-07

455

49 CFR 173.420 - Uranium hexafluoride (fissile, fissile excepted and non-fissile).  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Uranium hexafluoride (fissile, fissile excepted...Radioactive) Materials § 173.420 Uranium hexafluoride (fissile, fissile excepted...fissile, fissile excepted or non-fissile uranium hexafluoride must be offered for...

2013-10-01

456

28 CFR 79.52 - Criteria for eligibility for claims by uranium millers.  

Code of Federal Regulations, 2010 CFR

...Criteria for eligibility for claims by uranium millers. 79.52 Section 79.52... Eligibility Criteria for Claims by Uranium Millers § 79.52 Criteria for eligibility for claims by uranium millers. To establish...

2010-07-01

457

76 FR 67765 - Notice of Availability of Uranium Enrichment Fuel Cycle Facility's Inspection Reports Regarding...  

Federal Register 2010, 2011, 2012, 2013

...NRC-2010-0264] Notice of Availability of Uranium Enrichment Fuel Cycle Facility's Inspection...Gregory Chapman, Project Manager, Uranium Enrichment Branch, Division of Fuel Cycle...1954, as amended. The introduction of uranium hexafluoride into any module of the...

2011-11-02

458

49 CFR 173.420 - Uranium hexafluoride (fissile, fissile excepted and non-fissile).  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Uranium hexafluoride (fissile, fissile excepted...Radioactive) Materials § 173.420 Uranium hexafluoride (fissile, fissile excepted...fissile, fissile excepted or non-fissile uranium hexafluoride must be offered for...

2010-10-01

459

78 FR 23312 - Uranium Enrichment Fuel Cycle Inspection Reports Regarding Louisiana Energy Services, National...  

Federal Register 2010, 2011, 2012, 2013

...Docket No. 70-3103; NRC-2010-0264] Uranium Enrichment Fuel Cycle Inspection Reports...and has authorized the introduction of uranium hexafluoride (UF 6 ) into cascades...Commission. Brian W. Smith, Chief, Uranium Enrichment Branch, Division of Fuel...

2013-04-18

460

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

...false Applicability; description of the uranium, radium and vanadium ores subcategory...MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium Ores Subcategory...30 Applicability; description of the uranium, radium and vanadium ores...

2014-07-01

461

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

Code of Federal Regulations, 2010 CFR

...false Applicability; description of the uranium, radium and vanadium ores subcategory...MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium Ores Subcategory...30 Applicability; description of the uranium, radium and vanadium ores...

2010-07-01

462

49 CFR 173.434 - Activity-mass relationships for uranium and natural thorium.  

Code of Federal Regulations, 2012 CFR

... Activity-mass relationships for uranium and natural thorium. 173.434... Activity-mass relationships for uranium and natural thorium. The table of activity-mass relationships for uranium and natural thorium are as...

2012-10-01

463

10 CFR 40.66 - Requirements for advance notice of export shipments of natural uranium.  

Code of Federal Regulations, 2012 CFR

...advance notice of export shipments of natural uranium. 40.66 Section 40.66 Energy...advance notice of export shipments of natural uranium. (a) Each licensee authorized to export natural uranium, other than in the form of ore...

2012-01-01

464

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

Code of Federal Regulations, 2012 CFR

...false Applicability; description of the uranium, radium and vanadium ores subcategory...MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium Ores Subcategory...30 Applicability; description of the uranium, radium and vanadium ores...

2012-07-01

465

40 CFR 471.70 - Applicability; description of the uranium forming subcategory.  

Code of Federal Regulations, 2012 CFR

... Applicability; description of the uranium forming subcategory. 471.70 ...METAL POWDERS POINT SOURCE CATEGORY Uranium Forming Subcategory § 471.70 Applicability; description of the uranium forming subcategory. This...

2012-07-01

466

77 FR 19642 - Low Enriched Uranium From France: Final Results of Antidumping Duty Changed Circumstances Review  

Federal Register 2010, 2011, 2012, 2013

...Administration [A-427-818] Low Enriched Uranium From France: Final Results of Antidumping...antidumping duty order on low enriched uranium (LEU) from France on February 10, 2012...1\\ See Low Enriched Uranium from France: Preliminary Results of...

2012-04-02

467

49 CFR 173.434 - Activity-mass relationships for uranium and natural thorium.  

Code of Federal Regulations, 2011 CFR

... Activity-mass relationships for uranium and natural thorium. 173.434... Activity-mass relationships for uranium and natural thorium. The table of activity-mass relationships for uranium and natural thorium are as...

2011-10-01

468

49 CFR 173.434 - Activity-mass relationships for uranium and natural thorium.  

Code of Federal Regulations, 2010 CFR

... Activity-mass relationships for uranium and natural thorium. 173.434... Activity-mass relationships for uranium and natural thorium. The table of activity-mass relationships for uranium and natural thorium are as...

2010-10-01

469

49 CFR 173.420 - Uranium hexafluoride (fissile, fissile excepted and non-fissile).  

...2014-10-01 2014-10-01 false Uranium hexafluoride (fissile, fissile excepted...Radioactive) Materials § 173.420 Uranium hexafluoride (fissile, fissile excepted...fissile, fissile excepted or non-fissile uranium hexafluoride must be offered for...

2014-10-01

470

10 CFR 40.33 - Issuance of a license for a uranium enrichment facility.  

Code of Federal Regulations, 2012 CFR

... false Issuance of a license for a uranium enrichment facility. 40.33 Section...40.33 Issuance of a license for a uranium enrichment facility. (a) The...of the construction and operation of a uranium enrichment facility. The...

2012-01-01

471

77 FR 1956 - Application for a License To Export High-Enriched Uranium  

Federal Register 2010, 2011, 2012, 2013

...Application for a License To Export High-Enriched Uranium Pursuant to 10 CFR 110.70(b) ``Public Notice...kilograms To fabricate The Netherlands. Security Complex. Uranium uranium (9.3 targets at December 21,...

2012-01-12

472

40 CFR 421.320 - Applicability: Description of the secondary uranium subcategory.  

Code of Federal Regulations, 2013 CFR

...Applicability: Description of the secondary uranium subcategory. 421.320 Section...POINT SOURCE CATEGORY Secondary Uranium Subcategory § 421.320 Applicability: Description of the secondary uranium subcategory. The provisions...

2013-07-01

473

77 FR 73055 - Application for a License To Export High-Enriched Uranium  

Federal Register 2010, 2011, 2012, 2013

...Application for a License To Export High-Enriched Uranium Pursuant to 10 CFR 110.70 (b) ``Public Notice...fabricate targets The Netherlands. Security Complex. Uranium uranium-235 at CERCA AREVA October 10,...

2012-12-07

474

28 CFR 79.52 - Criteria for eligibility for claims by uranium millers.  

Code of Federal Regulations, 2011 CFR

...Criteria for eligibility for claims by uranium millers. 79.52 Section 79.52... Eligibility Criteria for Claims by Uranium Millers § 79.52 Criteria for eligibility for claims by uranium millers. To establish...

2011-07-01

475

10 CFR 40.66 - Requirements for advance notice of export shipments of natural uranium.  

Code of Federal Regulations, 2011 CFR

...advance notice of export shipments of natural uranium. 40.66 Section 40.66 Energy...advance notice of export shipments of natural uranium. (a) Each licensee authorized to export natural uranium, other than in the form of ore...

2011-01-01

476

77 FR 14001 - Continuation of Suspended Antidumping Duty Investigation: Uranium From the Russian Federation  

Federal Register 2010, 2011, 2012, 2013

...Suspended Antidumping Duty Investigation: Uranium From the Russian Federation AGENCY: Import...Suspending the Antidumping Investigation on Uranium from the Russian Federation (``Suspension...suspended antidumping duty investigation on uranium from the Russian Federation...

2012-03-08

477

40 CFR 471.70 - Applicability; description of the uranium forming subcategory.  

... Applicability; description of the uranium forming subcategory. 471.70 ...METAL POWDERS POINT SOURCE CATEGORY Uranium Forming Subcategory § 471.70 Applicability; description of the uranium forming subcategory. This...

2014-07-01

478

28 CFR 79.52 - Criteria for eligibility for claims by uranium millers.  

Code of Federal Regulations, 2013 CFR

...Criteria for eligibility for claims by uranium millers. 79.52 Section 79.52... Eligibility Criteria for Claims by Uranium Millers § 79.52 Criteria for eligibility for claims by uranium millers. To establish...

2013-07-01

479

40 CFR 471.70 - Applicability; description of the uranium forming subcategory.  

Code of Federal Regulations, 2010 CFR

... Applicability; description of the uranium forming subcategory. 471.70 ...METAL POWDERS POINT SOURCE CATEGORY Uranium Forming Subcategory § 471.70 Applicability; description of the uranium forming subcategory. This...

2010-07-01

480

10 CFR 40.33 - Issuance of a license for a uranium enrichment facility.  

Code of Federal Regulations, 2011 CFR

... false Issuance of a license for a uranium enrichment facility. 40.33 Section...40.33 Issuance of a license for a uranium enrichment facility. (a) The...of the construction and operation of a uranium enrichment facility. The...

2011-01-01

481

49 CFR 173.434 - Activity-mass relationships for uranium and natural thorium.  

Code of Federal Regulations, 2013 CFR

... Activity-mass relationships for uranium and natural thorium. 173.434... Activity-mass relationships for uranium and natural thorium. The table of activity-mass relationships for uranium and natural thorium are as...

2013-10-01

482

78 FR 72123 - Request To Amend a License to Export High-Enriched Uranium  

Federal Register 2010, 2011, 2012, 2013

...Request To Amend a License to Export High-Enriched Uranium Pursuant to 10 CFR 110.70 (b) ``Public Notice...HEU targets in Belgium. National Nuclear Security Uranium (HEU) uranium France for irradiation in Administration,...

2013-12-02

483

49 CFR 173.420 - Uranium hexafluoride (fissile, fissile excepted and non-fissile).  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Uranium hexafluoride (fissile, fissile excepted...Radioactive) Materials § 173.420 Uranium hexafluoride (fissile, fissile excepted...fissile, fissile excepted or non-fissile uranium hexafluoride must be offered for...

2011-10-01

484

78 FR 16483 - Notice of Availability of the Draft Uranium Leasing Program Programmatic Environmental Impact...  

Federal Register 2010, 2011, 2012, 2013

...ENERGY Notice of Availability of the Draft Uranium Leasing Program Programmatic Environmental...announces the availability of the Draft Uranium Leasing Program Programmatic Environmental...development, operations, and reclamation of uranium mines. The cooperating agencies on...

2013-03-15

485

10 CFR 140.13b - Amount of liability insurance required for uranium enrichment facilities.  

Code of Federal Regulations, 2013 CFR

...Amount of liability insurance required for uranium enrichment facilities. 140.13b ...Amount of liability insurance required for uranium enrichment facilities. Each holder...under Parts 40 or 70 of this chapter for a uranium enrichment facility that...

2013-01-01

486

77 FR 73056 - Application for a License To Export High-Enriched Uranium  

Federal Register 2010, 2011, 2012, 2013

...Application for a License To Export High-Enriched Uranium Pursuant to 10 CFR 110.70 (b) ``Public Notice...To fabricate targets Belgium. Security Complex. Uranium (93.2%). uranium-235 at CERCA AREVA Romans October 10,...

2012-12-07

487

77 FR 7128 - Low Enriched Uranium From France: Preliminary Results of Antidumping Duty Changed Circumstances...  

Federal Register 2010, 2011, 2012, 2013

...Administration [A-427-818] Low Enriched Uranium From France: Preliminary Results of Antidumping...antidumping duty order of low enriched uranium (LEU) from France.\\1\\ We preliminarily...1\\ See Low Enriched Uranium from France: Initiation of...

2012-02-10

488

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

Code of Federal Regulations, 2011 CFR

...false Applicability; description of the uranium, radium and vanadium ores subcategory...MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium Ores Subcategory...30 Applicability; description of the uranium, radium and vanadium ores...

2011-07-01

489

78 FR 60928 - Request To Amend a License To Export High-Enriched Uranium  

Federal Register 2010, 2011, 2012, 2013

...Request To Amend a License To Export High-Enriched Uranium Pursuant to 10 CFR 110.70 (b) ``Public Notice...manufacture HEU The Netherlands. National Nuclear Security Uranium uranium (17.1 targets in France Administration,...

2013-10-02

490

10 CFR 40.66 - Requirements for advance notice of export shipments of natural uranium.  

...advance notice of export shipments of natural uranium. 40.66 Section 40.66 Energy...advance notice of export shipments of natural uranium. (a) Each licensee authorized to export natural uranium, other than in the form of ore...

2014-01-01

491

10 CFR 40.66 - Requirements for advance notice of export shipments of natural uranium.  

Code of Federal Regulations, 2010 CFR

...advance notice of export shipments of natural uranium. 40.66 Section 40.66 Energy...advance notice of export shipments of natural uranium. (a) Each licensee authorized to export natural uranium, other than in the form of ore...

2010-01-01

492

28 CFR 79.52 - Criteria for eligibility for claims by uranium millers.  

Code of Federal Regulations, 2012 CFR

...Criteria for eligibility for claims by uranium millers. 79.52 Section 79.52... Eligibility Criteria for Claims by Uranium Millers § 79.52 Criteria for eligibility for claims by uranium millers. To establish...

2012-07-01

493

10 CFR 140.13b - Amount of liability insurance required for uranium enrichment facilities.  

Code of Federal Regulations, 2012 CFR

...Amount of liability insurance required for uranium enrichment facilities. 140.13b ...Amount of liability insurance required for uranium enrichment facilities. Each holder...under Parts 40 or 70 of this chapter for a uranium enrichment facility that...

2012-01-01

494

76 FR 63330 - Policy Regarding Submittal of Amendments for Processing of Equivalent Feed at Licensed Uranium...  

Federal Register 2010, 2011, 2012, 2013

...Processing of Equivalent Feed at Licensed Uranium Recovery Facilities AGENCY: Nuclear Regulatory...an NRC and Agreement State-licensed uranium recovery site. This action is necessary...Rulemaking Plan: Domestic Licensing of Uranium and Thorium Recovery...

2011-10-12

495

49 CFR 173.434 - Activity-mass relationships for uranium and natural thorium.  

... Activity-mass relationships for uranium and natural thorium. 173.434... Activity-mass relationships for uranium and natural thorium. The table of activity-mass relationships for uranium and natural thorium are as...

2014-10-01

496

76 FR 48882 - Agency Information Collections Activities; Comment Request for Uranium Concentrations in Private...  

Federal Register 2010, 2011, 2012, 2013

...Collections Activities; Comment Request for Uranium Concentrations in Private Wells in South-East...reference Information Collection 1028-NEW, Uranium concentrations in private wells in south-east...SUPPLEMENTARY INFORMATION: I. Abstract Uranium concentrations in groundwater that...

2011-08-09

497

40 CFR 471.70 - Applicability; description of the uranium forming subcategory.  

Code of Federal Regulations, 2011 CFR

... Applicability; description of the uranium forming subcategory. 471.70 ...METAL POWDERS POINT SOURCE CATEGORY Uranium Forming Subcategory § 471.70 Applicability; description of the uranium forming subcategory. This...