Low-Pressure and Low-Temperature Hydriding-Pulverization-Dehydriding Method for Producing Shape Memory Alloy Powders

Science.gov (United States)

Murguia, Silvia Briseño; Clauser, Arielle; Dunn, Heather; Fisher, Wendy; Snir, Yoav; Brennan, Raymond E.; Young, Marcus L.

2018-04-01

Shape memory alloys (SMAs) are of high interest as active, adaptive "smart" materials for applications such as sensors and actuators due to their unique properties, including the shape memory effect and pseudoelasticity. Binary NiTi SMAs have shown the most desirable properties, and consequently have generated the most commercial success. A major challenge for SMAs, in particular, is their well-known compositional sensitivity. Therefore, it is critical to control the powder composition and morphology. In this study, a low-pressure, low-temperature hydriding-pulverization-dehydriding method for preparing well-controlled compositions, size, and size distributions of SMA powders from wires is presented. Starting with three different diameters of as-drawn martensitic NiTi SMA wires, pre-alloyed NiTi powders of various well-controlled sizes are produced by hydrogen charging the wires in a heated H3PO4 solution. After hydrogen charging for different charging times, the wires are pulverized and subsequently dehydrided. The wires and the resulting powders are characterized using scanning electron microscopy, differential scanning calorimetry, and X-ray diffraction. The relationship between the wire diameter and powder size is investigated as a function of hydrogen charging time. The rate of diameter reduction after hydrogen charging of wire is also examined. Finally, the recovery behavior due to the shape memory effect is investigated after dehydriding.

Dehydriding and re-hydriding properties of high-energy ball milled LiBH{sub 4}+MgH{sub 2} mixtures

Energy Technology Data Exchange (ETDEWEB)

Crosby, Kyle; Shaw, Leon L. [Department of Chemical, Materials and Biomolecular Engineering, University of Connecticut, 97 North Eagleville Road, U-3136, Storrs, CT 06269 (United States)

2010-07-15

Here we report the first investigation of the dehydriding and re-hydriding properties of 2LiBH{sub 4} + MgH{sub 2} mixtures in the solid state. Such a study is made possible by high-energy ball milling of 2LiBH{sub 4}+MgH{sub 2} mixtures at liquid nitrogen temperature with the addition of graphite. The 2LiBH{sub 4}+MgH{sub 2} mixture ball milled under this condition exhibits a 5-fold increase in the released hydrogen at 265 C when compared with ineffectively ball milled counterparts. Furthermore, both LiBH{sub 4} and MgH{sub 2} contribute to hydrogen release in the solid state. The isothermal dehydriding/re-hydriding cycles at 265 C reveal that re-hydriding is dominated by re-hydriding of Mg. These unusual phenomena are explained based on the formation of nanocrystalline and amorphous phases, the increased defect concentration in crystalline compounds, and possible catalytic effects of Mg,MgH{sub 2} and LiBH{sub 4} on their dehydriding and re-hydriding properties. (author)

Development of laboratory apparatus dedicated to the study of hydride--dehydride reactions

International Nuclear Information System (INIS)

Wemple, R.P.; Kass, W.J.

1979-07-01

Hydrogen-compatible laboratory apparatus has been designed and developed to study hydride--dehydride reactions at elevated pressures and temperatures. The system has operated at pressures and temperatures up to 34 MPa and 550 0 C during experiments conducted on LiAlH 4 and NiZr. Instrumentation incorporated into the system also allows differential thermal analysis and acoustic emission data to be collected as the chemical reactions progress. 13 figures

Preparation of uranium nitride

International Nuclear Information System (INIS)

Potter, R.A.; Tennery, V.J.

1976-01-01

A process is described for preparing actinide-nitrides from massive actinide metal which is suitable for sintering into low density fuel shapes by partially hydriding the massive metal and simultaneously dehydriding and nitriding the dehydrided portion. The process is repeated until all of the massive metal is converted to a nitride

Dehydriding and rehydriding properties of Mg(NH2)2-LiH systems

International Nuclear Information System (INIS)

Aoki, M.; Noritake, T.; Nakamori, Y.; Towata, S.; Orimo, S.

2007-01-01

The dehydriding and rehydriding properties of the mixtures of 3Mg(NH 2 ) 2 + nLiH (n = 6, 8, and 12) were investigated by pressure-composition (p-c) isotherm and X-ray diffraction (XRD) measurements in order to clarify the effects of the LiH ratio n on the properties. The amounts of the hydrogen desorbed from the mixtures with n = 6, 8, and 12 were 5.4, 5.1, and 4.5 mass%, respectively; this indicates that the amounts on a unit mass basis decrease with increasing n. However, the molar ratios of the desorbed hydrogen to the mixtures estimated from the amounts were almost equal, and also the features of the p-c isotherms were similar to each other. Moreover, the Li 2 Mg(NH) 2 and LiH phases were observed in XRD profiles of all the mixtures after p-c isotherm measurements. These results suggest that the dehydriding reaction of the mixtures of 3Mg(NH 2 ) 2 + nLiH (n = 6, 8, and 12) under hydrogen pressure is not dominantly affected by the value of n. On the other hand, the amounts of the ammonia desorbed from the mixtures detected by mass spectroscopy decreased with increasing n

Hydriding and dehydriding rates of Mg, Mg-10TaF5, and Mg-10NbF5 prepared via reactive mechanical grinding

Science.gov (United States)

Song, Myoung Youp; Kwak, Young Jun; Lee, Seong Ho; Park, Hye Ryoung

2015-01-01

In this work, TaF5 and NbF5 were chosen as additives to enhance the hydriding and dehydriding rates of Mg. Mg, Mg-10TaF5, and Mg-10NbF5 samples were prepared by reactive mechanical grinding. The hydriding and dehydriding properties of the samples were then examined. Mg-10TaF5 had the largest amount of hydrogen absorbed for 30 min and the highest initial dehydriding rate after incubation period, followed in order by Mg-10NbF5, and Mg. At 593 K under 12 bar H2 at the first cycle, Mg-10TaF5 absorbed 3.63 wt% H for 5 min and 4.53 wt% H for 30 min. At 593 K under 1.0 bar H2 at the first cycle, Mg-10TaF5 desorbed 0 wt% H for 2.5 min, 0.59 wt% H for 5 min, 3.42 wt% H for 30 min, and 4.24 wt% H for 60 min. The reactive mechanical grinding of Mg with TaF5 or NbF5 is believed to have facilitated the nucleation and to have decreased the diffusion distances of hydrogen atoms. These two effects are believed to have increased the hydriding and dehydriding rates of Mg. The MgF2 and Ta2H formed in Mg-10TaF5, and the MgF2, NbH2, and NbF3 formed in Mg-10NbF5 are considered to have enhanced both of these effects.

Experimental study on uranium alloys for hydrogen storage

International Nuclear Information System (INIS)

Deaconu, M.; Meleg, T.; Dinu, A.; Mihalache, M.; Ciuca, I.; Abrudeanu, M.

2013-01-01

The heaviest isotope of hydrogen is one of critically important elements in the field of fusion reactor technology. Conventionally, uranium metal is used for the storage of heavier isotopes of hydrogen (D and T). Under appropriate conditions, uranium absorbs hydrogen to form a stable UH 3 compound when exposed to molecular hydrogen at the temperature range of 300-500 O C at varied operating pressure below one atmosphere. However, hydriding-dehydriding on pure uranium disintegrates the specimen into fine powder. The powder is highly pyrophoric and has low heat conductivity, which makes it difficult to control the temperature, and has a high possibility of contamination Due to the powdering effect as hydrogen in uranium, alloying uranium with other metal looks promising for the use of hydrogen storage materials. This paper has the aim to study the hydriding properties of uranium alloys, including U-Ti U-Mo and U-Ni. The uranium alloys specimens were prepared by melting the constituent elements by means of simultaneous measurements of thermo-gravimetric and differential thermal analyses (TGA-DTA) and studied in as cast condition as hydrogen storage materials. Then samples were thermally treated under constant flow of hydrogen, at various temperatures between 573-973 0 K. The structural and absorption properties of the products obtained were examined by thermo-gravimetric analysis (TG), X-ray diffraction (XRD) and scanning electron microscopy (SEM). They slowly reacted with hydrogen to form the ternary hydride and the hydrogenated samples mainly consisted of the pursued ternary hydride bat contained also U or UO 2 and some transient phase. (authors)

Improved dehydriding property of polyvinylpyrrolidone coated Mg-Ni hydrogen storage nano-composite prepared by hydriding combustion synthesis and wet mechanical milling

Directory of Open Access Journals (Sweden)

Linglong Yao

2018-02-01

Full Text Available In this work, polyvinylpyrrolidone (PVP coated Mg95Ni5 nano-composites were prepared by hydriding combustion synthesis (HCS plus wet mechanical milling (WM with tetrahydrofuran (THF and donated as WM-x wt% PVP (x = 1, 3, 5 and 7 respectively. The phase compositions, microstructures and dehydriding property, as well as the co-effect of PVP and THF were investigated in detail. XRD results showed that the average crystal size of MgH2 in the milled Mg95Ni5 decreased from 23 nm without PVP to 18 nm with 1 wt% PVP. The peak temperature of dehydrogenation of MgH2 in the milled Mg95Ni5 decreased from 293.0 °C without THF to 250.4 °C with THF. The apparent activation energy for decomposition of MgH2 in WM-7 wt% PVP was estimated to be 66.94 kJ/mol, which is 37.70 kJ/mol lower than that of milled Mg95Ni5 without THF and PVP. PVP and THF can facilitate the refinement of particle size during mechanical milling process. Attributed to small particle sizes and synergistic effect of PVP and THF, the composites exhibit markedly improved dehydriding properties. Keywords: Mg-Ni-PVP, Composite, Mg-based alloy, Wet mechanical milling, Dehydriding temperature

Dehydriding reaction of Mg(NH2)2-LiH system under hydrogen pressure

International Nuclear Information System (INIS)

Aoki, M.; Noritake, T.; Kitahara, G.; Nakamori, Y.; Towata, S.; Orimo, S.

2007-01-01

The dehydriding and structural properties of the 3Mg(NH 2 ) 2 + 12LiH system under hydrogen pressure were investigated using the pressure-composition (p-c) isotherm measurement and X-ray diffraction (XRD) analysis. Two distinct regions, a plateau region and a sloping region, can be seen on the p-c isotherms and the amount of the desorbed hydrogen at 523 K was 4.9 mass%. The enthalpy of hydrogenation calculated using a van't Hoff plot was -46 kJ/mol H 2 . The dehydriding reaction was proposed for the 3Mg(NH 2 ) 2 + 12LiH system based on the obtained p-c isotherms and XRD profiles and chemical valences of Li, Mg, N, and H. In the plateau region on the p-c isotherm, Mg(NH 2 ) 2 , Li 4 Mg 3 (NH 2 ) 2 (NH) 4 (tetragonal), and LiH phases coexist and the molar ratio of the Li 4 Mg 3 (NH 2 ) 2 (NH) 4 phase increases (while those of Mg(NH 2 ) 2 and LiH phases decrease) with the amount of the desorbed hydrogen. On the other hand, the mixture of Li 4+x Mg 3 (NH 2 ) 2-x (NH) 4+x + (8-x)LiH (0 ≤ x ≤ 2) is formed and the lattice volume of the Li 4+x Mg 3 (NH 2 ) 2-x (NH) 4+x phase continuously increases with the amount of the desorbed hydrogen in the sloping region on the p-c isotherm

Effect of amorphous Mg50Ni50 on hydriding and dehydriding behavior of Mg2Ni alloy

International Nuclear Information System (INIS)

Guzman, D.; Ordonez, S.; Fernandez, J.F.; Sanchez, C.; Serafini, D.; Rojas, P.A.; Aguilar, C.; Tapia, P.

2011-01-01

Composite Mg 2 Ni (25 wt.%) amorphous Mg 50 Ni 50 was prepared by mechanical milling starting with nanocrystalline Mg 2 Ni and amorphous Mg 50 Ni 50 powders, by using a SPEX 8000 D mill. The morphological and microstructural characterization of the powders was performed via scanning electron microscopy and X-ray diffraction. The hydriding characterization of the composite was performed via a solid gas reaction method in a Sievert's-type apparatus at 363 K under an initial hydrogen pressure of 2 MPa. The dehydriding behavior was studied by differential thermogravimetry. On the basis of the results, it is possible to conclude that amorphous Mg 50 Ni 50 improved the hydriding and dehydriding kinetics of Mg 2 Ni alloy upon cycling. A tentative rationalization of experimental observations is proposed. - Research Highlights: → First study of the hydriding behavior of composite Mg 2 Ni (25 wt.%) amorphous Mg 50 Ni 50 . → Microstructural characterization of composite material using XRD and SEM was obtained. → An improved effect of Mg 50 Ni 50 on the Mg 2 Ni hydriding behavior was verified. → The apparent activation energy for the hydrogen desorption of composite was obtained.

NURE uranium deposit model studies

International Nuclear Information System (INIS)

Crew, M.E.

1981-01-01

The National Uranium Resource Evaluation (NURE) Program has sponsored uranium deposit model studies by Bendix Field Engineering Corporation (Bendix), the US Geological Survey (USGS), and numerous subcontractors. This paper deals only with models from the following six reports prepared by Samuel S. Adams and Associates: GJBX-1(81) - Geology and Recognition Criteria for Roll-Type Uranium Deposits in Continental Sandstones; GJBX-2(81) - Geology and Recognition Criteria for Uraniferous Humate Deposits, Grants Uranium Region, New Mexico; GJBX-3(81) - Geology and Recognition Criteria for Uranium Deposits of the Quartz-Pebble Conglomerate Type; GJBX-4(81) - Geology and Recognition Criteria for Sandstone Uranium Deposits in Mixed Fluvial-Shallow Marine Sedimentary Sequences, South Texas; GJBX-5(81) - Geology and Recognition Criteria for Veinlike Uranium Deposits of the Lower to Middle Proterozoic Unconformity and Strata-Related Types; GJBX-6(81) - Geology and Recognition Criteria for Sandstone Uranium Deposits of the Salt Wash Type, Colorado Plateau Province. A unique feature of these models is the development of recognition criteria in a systematic fashion, with a method for quantifying the various items. The recognition-criteria networks are used in this paper to illustrate the various types of deposits

The UMo Powder Production Process of UMo-Al Dispersion Fuel for Research Reactor has been Studied

International Nuclear Information System (INIS)

Supardjo

2007-01-01

Development of UMo-Al dispersion fuel with low enrichment uranium ( 3 ), a relatively large range of γ phase and easily reprocessed. Using UMo alloy as nuclear fuel, uranium density can be increased until 9.0 g/cm 3 , is higher than that of U 3 Si 2 -Al fuel that has only maximum Uranium density 6.0 g/cm 3 . Because of ductility of UMo alloy, thus exact and economic powder production method is needed. Some powder production methods are mechanical crushing (milling, grinding, etc), cryogenic mechanical crushing, atomization, and Hydride-Dehydride. The mechanical crushing and cryogenic mechanical crushing methods are difficult to be performed, time consuming and have high impurity products. However, atomization and hydride-dehydride methods are performed easily, fast and have low impurity products. The product of atomization process is spherical and uniform shape, but, another processes have irregular shape. The evaluation result of some methods showed that hydride-dehydride and atomization methods are more suitable for producing UMo powder than that of another methods. (author)

Documentation of the Uranium Market Model (UMM)

International Nuclear Information System (INIS)

1989-01-01

The Uranium Market Model is used to make projections of activity in the US uranium mining and milling industry. The primary data sources were EIA, the Nuclear Assurance Corporation, and, to a lesser extent, Nuexco and Nuclear Resources International. The Uranium Market Model is a microeconomic simulation model in which uranium supplied by the mining and milling industry is provided to meet the demand for uranium by electric utilities with nuclear power plants. Uranium is measured on a U 3 O 8 (uranium oxide) equivalent basis. The model considers every major production center and utility on a worldwide basis (with Centrally Planned Economies considered in a limited way), and makes annual projections for each major uranium production and consumption region in the world. Typically, nine regions are used: the United States, Canada, Australia, South Africa, Other Africa, Europe, Latin America, the Far East, and Other. Production centers and utilities are identified as being in one of these regions. In general, the model can accommodate any user-provided set of regional definitions and data

Effect of amorphous Mg{sub 50}Ni{sub 50} on hydriding and dehydriding behavior of Mg{sub 2}Ni alloy

Energy Technology Data Exchange (ETDEWEB)

Guzman, D., E-mail: danny.guzman@uda.cl [Departamento de Ingenieria en Metalurgia, Facultad de Ingenieria, Universidad de Atacama y Centro Regional de Investigacion y Desarrollo Sustentable de Atacama (CRIDESAT), Av. Copayapu 485, Copiapo (Chile); Ordonez, S. [Departamento de Ingenieria Metalurgica, Facultad de Ingenieria, Universidad de Santiago de Chile, Av. Lib. Bernardo O' Higgins 3363, Santiago (Chile); Fernandez, J.F.; Sanchez, C. [Departamento de Fisica de Materiales, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco 28049, Madrid (Spain); Serafini, D. [Departamento de Fisica, Facultad de Ciencias, Universidad de Santiago de Chile and Center for Interdisciplinary Research in Materials, CIMAT, Av. Lib. Bernardo O' Higgins 3363, Santiago (Chile); Rojas, P.A. [Escuela de Ingenieria Mecanica, Facultad de Ingenieria, Av. Los Carrera 01567, Quilpue, Pontificia Universidad Catolica de Valparaiso, PUCV (Chile); Aguilar, C. [Departamento de Ingenieria Metalurgica y Materiales, Universidad Tecnica Federico Santa Maria, Av. Espana 1680, Valparaiso (Chile); Tapia, P. [Departamento de Ingenieria en Metalurgia, Facultad de Ingenieria, Universidad de Atacama, Av. Copayapu 485, Copiapo (Chile)

2011-04-15

Composite Mg{sub 2}Ni (25 wt.%) amorphous Mg{sub 50}Ni{sub 50} was prepared by mechanical milling starting with nanocrystalline Mg{sub 2}Ni and amorphous Mg{sub 50}Ni{sub 50} powders, by using a SPEX 8000 D mill. The morphological and microstructural characterization of the powders was performed via scanning electron microscopy and X-ray diffraction. The hydriding characterization of the composite was performed via a solid gas reaction method in a Sievert's-type apparatus at 363 K under an initial hydrogen pressure of 2 MPa. The dehydriding behavior was studied by differential thermogravimetry. On the basis of the results, it is possible to conclude that amorphous Mg{sub 50}Ni{sub 50} improved the hydriding and dehydriding kinetics of Mg{sub 2}Ni alloy upon cycling. A tentative rationalization of experimental observations is proposed. - Research Highlights: {yields} First study of the hydriding behavior of composite Mg{sub 2}Ni (25 wt.%) amorphous Mg{sub 50}Ni{sub 50}. {yields} Microstructural characterization of composite material using XRD and SEM was obtained. {yields} An improved effect of Mg{sub 50}Ni{sub 50} on the Mg{sub 2}Ni hydriding behavior was verified. {yields} The apparent activation energy for the hydrogen desorption of composite was obtained.

Uranium(VI) speciation: modelling, uncertainty and relevance to bioavailability models. Application to uranium uptake by the gills of a freshwater bivalve

International Nuclear Information System (INIS)

Denison, F.H.

2004-07-01

The effects of varying solution composition on the interactions between uranium(VI) and excised gills of the freshwater bivalve Corbicula fluminea have been investigated in well defined solution media. A significant reduction in the uptake of uranium was observed on increasing the concentrations of the uranium complexing ligands citrate and carbonate. Saturation kinetics as a function of uranium concentration at a pH value of 5.0 were observed, indicating that the uptake of uranium is a facilitated process, probably involving one or several trans-membrane transport systems. A relatively small change in the uptake of uranium was found as a function of pH (factor of ca. 2), despite the extremely large changes to the solution speciation of uranium within the range of pH investigated (5.0 - 7.5). A comprehensive review of the thermodynamic data relevant to the solution composition domain employed for this study was performed. Estimates of the uncertainties for the formation constants of aqueous uranium(VI) species were integrated into a thermodynamic database. A computer program was written to predict the equilibrium distribution of uranium(VI) in simple aqueous systems, using thermodynamic parameter mean-values. The program was extended to perform Monte Carlo and Quasi Monte Carlo uncertainty analyses, incorporating the thermodynamic database uncertainty estimates, to quantitatively predict the uncertainties inherent in predicting the solution speciation of uranium. The use of thermodynamic equilibrium modelling as a tool for interpreting the bioavailability of uranium(VI) was investigated. Observed uranium(VI) uptake behaviour was interpreted as a function of the predicted changes to the solution speciation of uranium. Different steady-state or pre-equilibrium approaches to modelling uranium uptake were tested. Alternative modelling approaches were also tested, considering the potential changes to membrane transport system activity or sorption characteristics on

Economic model of the US uranium market

International Nuclear Information System (INIS)

Owen, A.D.

1984-01-01

An economic model of the US uranium market is developed using annual data for the period 1966-81. The model consists of five stochastic equations explaining uranium consumption, forward commitments, mine production, contract prices, and spot prices. A forecasting exercise is also undertaken. By way of essential background information, however, an analysis of current trends in the international uranium market is given, followed by a summary of historical price movements in the US uranium market. A brief discussion on the current state of the US market precedes the statistical analysis. 19 footnotes and references, 3 tables

Powder Metallurgy of Uranium Alloy Fuels for TRU-Burning Reactors Final Technical Report

Energy Technology Data Exchange (ETDEWEB)

McDeavitt, Sean M

2011-04-29

outlining the beginning of the materials processing setup. Also included within this section is a thesis proposal by Jeff Hausaman. Appendix C contains the public papers and presentations introduced at the 2010 American Nuclear Society Winter Meeting. Appendix A—MSNE theses of David Garnetti and Grant Helmreich and proposal by Jeff Hausaman A.1 December 2009 Thesis by David Garnetti entitled “Uranium Powder Production Via Hydride Formation and Alpha Phase Sintering of Uranium and Uranium-Zirconium Alloys for Advanced Nuclear Fuel Applications” A.2 September 2009 Presentation by David Garnetti (same title as document in Appendix B.1) A.3 December 2010 Thesis by Grant Helmreich entitled “Characterization of Alpha-Phase Sintering of Uranium and Uranium-Zirconium Alloys for Advanced Nuclear Fuel Applications” A.4 October 2010 Presentation by Grant Helmreich (same title as document in Appendix B.3) A.5 Thesis Proposal by Jeffrey Hausaman entitled “Hot Extrusion of Alpha Phase Uranium-Zirconium Alloys for TRU Burning Fast Reactors” Appendix B—External presentations introduced at the 2010 ANS Winter Meeting B.1 J.S. Hausaman, D.J. Garnetti, and S.M. McDeavitt, “Powder Metallurgy of Alpha Phase Uranium Alloys for TRU Burning Fast Reactors,” Proceedings of 2010 ANS Winter Meeting, Las Vegas, Nevada, USA, November 7-10, 2010 B.2 PowerPoint Presentation Slides from C.1 B.3 G.W. Helmreich, W.J. Sames, D.J. Garnetti, and S.M. McDeavitt, “Uranium Powder Production Using a Hydride-Dehydride Process,” Proceedings of 2010 ANS Winter Meeting, Las Vegas, Nevada, USA, November 7-10, 2010 B.4. PowerPoint Presentation Slides from C.3 B.5 Poster Presentation from C.3 Appendix C—Fuel cycle research and development undergraduate materials and poster presentation C.1 Poster entitled “Characterization of Alpha-Phase Sintering of Uranium and Uranium-Zirconium Alloys” presented at the Fuel Cycle Technologies Program Annual Meeting C.2 April 2011 Honors Undergraduate Thesis

Powder Metallurgy of Uranium Alloy Fuels for TRU-Burning Reactors Final Technical Report

International Nuclear Information System (INIS)

McDeavitt, Sean M.

2011-01-01

beginning of the materials processing setup. Also included within this section is a thesis proposal by Jeff Hausaman. Appendix C contains the public papers and presentations introduced at the 2010 American Nuclear Society Winter Meeting. Appendix A - MSNE theses of David Garnetti and Grant Helmreich and proposal by Jeff Hausaman A.1 December 2009 Thesis by David Garnetti entitled 'Uranium Powder Production Via Hydride Formation and Alpha Phase Sintering of Uranium and Uranium-Zirconium Alloys for Advanced Nuclear Fuel Applications' A.2 September 2009 Presentation by David Garnetti (same title as document in Appendix B.1) A.3 December 2010 Thesis by Grant Helmreich entitled 'Characterization of Alpha-Phase Sintering of Uranium and Uranium-Zirconium Alloys for Advanced Nuclear Fuel Applications' A.4 October 2010 Presentation by Grant Helmreich (same title as document in Appendix B.3) A.5 Thesis Proposal by Jeffrey Hausaman entitled 'Hot Extrusion of Alpha Phase Uranium-Zirconium Alloys for TRU Burning Fast Reactors' Appendix B - External presentations introduced at the 2010 ANS Winter Meeting B.1 J.S. Hausaman, D.J. Garnetti, and S.M. McDeavitt, 'Powder Metallurgy of Alpha Phase Uranium Alloys for TRU Burning Fast Reactors,' Proceedings of 2010 ANS Winter Meeting, Las Vegas, Nevada, USA, November 7-10, 2010 B.2 PowerPoint Presentation Slides from C.1 B.3 G.W. Helmreich, W.J. Sames, D.J. Garnetti, and S.M. McDeavitt, 'Uranium Powder Production Using a Hydride-Dehydride Process,' Proceedings of 2010 ANS Winter Meeting, Las Vegas, Nevada, USA, November 7-10, 2010 B.4. PowerPoint Presentation Slides from C.3 B.5 Poster Presentation from C.3 Appendix C - Fuel cycle research and development undergraduate materials and poster presentation C.1 Poster entitled 'Characterization of Alpha-Phase Sintering of Uranium and Uranium-Zirconium Alloys' presented at the Fuel Cycle Technologies Program Annual Meeting C.2 April 2011 Honors Undergraduate Thesis by William Sames, Research Fellow

Uranium resources evaluation model as an exploration tool

International Nuclear Information System (INIS)

Ruzicka, V.

1976-01-01

Evaluation of uranium resources, as conducted by the Uranium Resources Evaluation Section of the Geological Survey of Canada, comprises operations analogous with those performed during the preparatory stages of uranium exploration. The uranium resources evaluation model, simulating the estimation process, can be divided into four steps. The first step includes definition of major areas and ''unit subdivisions'' for which geological data are gathered, coded, computerized and retrieved. Selection of these areas and ''unit subdivisions'' is based on a preliminary appraisal of their favourability for uranium mineralization. The second step includes analyses of the data, definition of factors controlling uranium minearlization, classification of uranium occurrences into genetic types, and final delineation of favourable areas; this step corresponds to the selection of targets for uranium exploration. The third step includes geological field work; it is equivalent to geological reconnaissance in exploration. The fourth step comprises computation of resources; the preliminary evaluation techniques in the exploration are, as a rule, analogous with the simplest methods employed in the resource evaluation. The uranium resources evaluation model can be conceptually applied for decision-making during exploration or for formulation of exploration strategy using the quantified data as weighting factors. (author)

Comparison of two uranium-market forecasting models

International Nuclear Information System (INIS)

Bleistein, S.; Recek, J.

1983-01-01

The techniques and methodologies, similarities and differences, and the results of two uranium market computer models - the Uranium Supply Analysis System and the EUREKA model - are surveyed. These models can be of use to electric utilities in developing procurement strategies or planning new reactor requirements. The models are designed to simulate actual market performance of the domestic uranium industry under varying user-specified assumptions. These models provide output in the form of projections of variables of interest, such as investment in exploration and new production capacity, additions to reserves and resources, and adjustments in inventories. Comparison between the models is demonstrative of how output can vary even with use of the same input data. Utilities may profit by the comparison with respect to the task of selecting models on the basis of obtaining the most-useful solution for a given problem. 18 figures

An analytic uranium sources model

International Nuclear Information System (INIS)

Singer, C.E.

2001-01-01

This document presents a method for estimating uranium resources as a continuous function of extraction costs and describing the uncertainty in the resulting fit. The estimated functions provide convenient extrapolations of currently available data on uranium extraction cost and can be used to predict the effect of resource depletion on future uranium supply costs. As such, they are a useful input for economic models of the nuclear energy sector. The method described here pays careful attention to minimizing built-in biases in the fitting procedure and defines ways to describe the uncertainty in the resulting fits in order to render the procedure and its results useful to the widest possible variety of potential users. (author)

Model of the coercion uranium hexafluoride on a human body

International Nuclear Information System (INIS)

Babenko, S.P.

2007-01-01

A method for calculating certain quantities characterizing the effect of uranium hexafluoride (UF 6 ) on the human body under industrial conditions in uranium enrichment plants is described. It is assumed that the effect is determined by uranium and fluorine inhaled together with the products of hydrolysis of uranium hexafluoride. The proposed complex model consists of three models, the first of which describes the contamination of the industrial environment and the second and third describe inhalation and percutaneous intake. A relation is obtained between uranium and fluorine intake and the uranium hexafluoride concentration in air at the moment the compound is discharged [ru

Integrated prospecting model in Jinguanchong uranium deposit

International Nuclear Information System (INIS)

Xie Yongjian

2006-01-01

Jinguanchong uranium deposit is large in scale, which brings difficulties to prospecting and researches. Based on conditions of mineral-formation, geophysics and geochemistry, this paper summarizes a few geophysical and geochemical prospecting methods applied to this deposit. The principles, characteristics, application condition and exploration phases of these prospecting methods are discussed and some prospecting examples are also given in the prospecting for Jinguanchong uranium deposit. Based on summarizing the practice and effects of different methods such as gamma and electromagnetic method, soil emanation prospecting, track etch technique and polonium method used in uranium prospecting, the author finally puts forward a primary uranium prospecting model for the further prospecting in Jinguanchong uranium deposit through combining the author's experience with practice. (authors)

Uranium(VI) transport modeling: geochemical data and submodels

International Nuclear Information System (INIS)

Tripathi, V.S.

1984-01-01

Understanding the geochemical mobility of U(VI) and modeling its transport is important in several contexts including ore genesis, uranium exploration, nuclear and mill-tailings waste management, and solution mining of uranium ores. Adsorption is a major control on partitioning of solutes at the mineral/solution interface. The effect of carbonate, fluoride, and phosphate complexing on adsorption of uranium was investigated. A critical compilation of stability constants of inorganic complexes and solid compounds of U(VI) necessary for proper design of experiment and for modeling transport of uranium was prepared. The general features of U(VI) adsorption in ligand-free systems are similar to those characteristic of other hydrolyzable metal ions. The adsorption processes studied were found to be reversible. The adsorption model developed in ligand-free systems, when solution complexing is taken into account, proved remarkably successful in describing adsorption of uranium in the presence of carbonate and fluoride. The presence of phosphate caused a much smaller decrease in the extent of adsorption than expected; however, a critical reassessment of the stability of UO 2 2+ .HPO 4 2- complexes, showed that phosphato complexes, if any, are extremely weak under experimental conditions. Removal of uranium may have occurred due to precipitation of sodium uranyl phosphates in addition to adsorption

Development of interpretation models for PFN uranium log analysis

International Nuclear Information System (INIS)

Barnard, R.W.

1980-11-01

This report presents the models for interpretation of borehole logs for the PFN (Prompt Fission Neutron) uranium logging system. Two models have been developed, the counts-ratio model and the counts/dieaway model. Both are empirically developed, but can be related to the theoretical bases for PFN analysis. The models try to correct for the effects of external factors (such as probe or formation parameters) in the calculation of uranium grade. The theoretical bases and calculational techniques for estimating uranium concentration from raw PFN data and other parameters are discussed. Examples and discussions of borehole logs are included

Metallogenic model for continental volcanic-type rich and large uranium deposits

International Nuclear Information System (INIS)

Chen Guihua

1998-01-01

A metallogenic model for continental volcanic-type rich and large/super large uranium deposits has been established on the basis of analysis of occurrence features and ore-forming mechanism of some continental volcanic-type rich and large/super large uranium deposits in the world. The model proposes that uranium-enriched granite or granitic basement is the foundation, premetallogenic polycyclic and multistage volcanic eruptions are prerequisites, intense tectonic-extensional environment is the key for the ore formation, and relatively enclosed geologic setting is the reliable protection condition of the deposit. By using the model the author explains the occurrence regularities of some rich and large/super large uranium deposits such as Strelichof uranium deposit in Russia, Dornot uranium deposit in Mongolia, Olympic Dam Cu-U-Au-REE deposit in Australia, uranium deposit No.460 and Zhoujiashan uranium deposit in China, and then compares the above deposits with a large poor uranium deposit No.661 as well

Preliminary discussion on uranium metallogenic models of China's in-situ leachable sandstone-type uranium deposits

International Nuclear Information System (INIS)

Zhang Jindai; Xu Gaozhong; Chen Anping; Wang Cheng

2005-01-01

By comprehensively analyzing metallogenic environments and main ore-controlling factors of important uranium metallogenic regions of in-situ leachable sandstone-type uranium deposits at the southern margin of Yili basin, at the south-western margin of Turpan-Hami basin and in the northeastern Ordos basin, the authors of this paper discuss the metallogenic models of China's in-situ leachable sandstone-type uranium deposits, and suggest that the interlayer oxidation zone type uranium deposits in Yili and Turpan-Hami basins are basically controlled by favourable structures, sedimentary formations and interlayer oxidation zone, and are characterized by multistage uranium concentration, namely the uranium pre-concentration of ore-hosting sedimentary formation, the uranium ore-formation in the stage of supergenic epigenetic reworking, and the further superimposition enrichment of post-ore tectonic activity. However, the interlayer oxidation zone type uranium deposit in the northeastern Ordos was formed after the formation of the secondary reduction. So, paleo-interlayer oxidation zone type uranium mineralization has the mineralization size much greater than the former two. (authors)

Cost study on waste management at three model Canadian uranium mines

International Nuclear Information System (INIS)

1984-03-01

A waste management cost study was initiated to determine the capital and operating costs of three different uranium waste management systems which incorporate current technologies being used in Canadian uranium mining operations. Cost estimates were to be done to a thirty percent level of accuracy and were to include all waste management related costs of a uranium ore processing facility. Each model is based on an annual uranium production of 1,923,000 kg U (5,000,000 lbs U 3 O 8 ) with a total operating life of 20 years for the facility. The three models, A, B, and C, are based on three different uranium ore grades, 0.10 percent U 3 O 8 , 0.475 percent U 3 O 8 and 1.5 percent U 3 O 8 respectively. Yellowcake production is assumed to start in January 1984. Model A is based on a conceptual 7,180 tonne per day uranium ore processing facility and waste management system typical of uranium operations in the Elliot Lake area of northern Ontario with an established infrastructure. Model B is a 1.512 tonne per day operation based on a remote uranium operation typical of the Athabasca Basin properties in northern Saskatchewan. Model C is a 466 tonne per day operation processing a high-grade uranium ore containing arsenic and heavy metal concentrations typical of some northern Saskatchewan deposits

Validation of the WATEQ4 geochemical model for uranium

International Nuclear Information System (INIS)

Krupka, K.M.; Jenne, E.A.; Deutsch, W.J.

1983-09-01

As part of the Geochemical Modeling and Nuclide/Rock/Groundwater Interactions Studies Program, a study was conducted to partially validate the WATEQ4 aqueous speciation-solubility geochemical model for uranium. The solubility controls determined with the WATEQ4 geochemical model were in excellent agreement with those laboratory studies in which the solids schoepite [UO 2 (OH) 2 . H 2 O], UO 2 (OH) 2 , and rutherfordine ((UO 2 CO 3 ) were identified as actual solubility controls for uranium. The results of modeling solution analyses from laboratory studies of uranyl phosphate solids, however, identified possible errors in the characterization of solids in the original solubility experiments. As part of this study, significant deficiencies in the WATEQ4 thermodynamic data base for uranium solutes and solids were corrected. Revisions included recalculation of selected uranium reactions. Additionally, thermodynamic data for the hydroxyl complexes of U(VI), including anionic (VI) species, were evaluated (to the extent permitted by the available data). Vanadium reactions were also added to the thermodynamic data base because uranium-vanadium solids can exist in natural ground-water systems. This study is only a partial validation of the WATEQ4 geochemical model because the available laboratory solubility studies do not cover the range of solid phases, alkaline pH values, and concentrations of inorganic complexing ligands needed to evaluate the potential solubility of uranium in ground waters associated with various proposed nuclear waste repositories. Further validation of this or other geochemical models for uranium will require careful determinations of uraninite solubility over the pH range of 7 to 10 under highly reducing conditions and of uranyl hydroxide and phosphate solubilities over the pH range of 7 to 10 under oxygenated conditions

Analytical and numerical models of uranium ignition assisted by hydride formation

International Nuclear Information System (INIS)

Totemeier, T.C.; Hayes, S.L.

1996-01-01

Analytical and numerical models of uranium ignition assisted by the oxidation of uranium hydride are described. The models were developed to demonstrate that ignition of large uranium ingots could not occur as a result of possible hydride formation during storage. The thermodynamics-based analytical model predicted an overall 17 C temperature rise of the ingot due to hydride oxidation upon opening of the storage can in air. The numerical model predicted locally higher temperature increases at the surface; the transient temperature increase quickly dissipated. The numerical model was further used to determine conditions for which hydride oxidation does lead to ignition of uranium metal. Room temperature ignition only occurs for high hydride fractions in the nominally oxide reaction product and high specific surface areas of the uranium metal

Modeling of uranium bioleaching by Acidithiobacillus ferrooxidans

International Nuclear Information System (INIS)

Rashidi, A.; Safdari, J.; Roosta-Azad, R.; Zokaei-Kadijani, S.

2012-01-01

Highlights: ► A mathematical model for the mesophilic bioleaching of uraninite is introduced. ► New rate expressions are used for the iron precipitation and uranium leaching rates. ► Good fits of the model are obtained, while the values of the parameters are within the range expected. ► The model can be applied to other bioleaching processes under the same conditions. - Abstract: In this paper, a mathematical model for the mesophilic bioleaching of uraninite is developed. The case of constant temperature, pH, and initial ore concentration is considered. The model is validated by comparing the calculated and measured values of uranium extraction, ferric and ferrous iron in solution, and cell concentration. Good fits of the model were obtained, while the values of the parameters were within the range expected. New rate expressions were used for the iron precipitation and uranium leaching rates. The rates of chemical leaching and ferric precipitation are related to the ratio of ferric to ferrous in solution. The fitted parameters can be considered applicable only to this study. In contrast, the model equation is general and can be applied to bioleaching under the same conditions.

A coalescence model for uranium exploration

International Nuclear Information System (INIS)

Stuart-Williams, V.; Taylor, C.M.

1983-01-01

Uranium mineralization was found in the Pristerognathus-Diictodon Assemblage Zone of the Teekloof Formation, Beaufort Group, west of Beaufort West, Cape Province, South Africa. All the anomalies can be related to a single mineralization model. Mineralization is found at the termination of a silt parting between two coalescing sandstones and lies in the lower sandstone as an inclined zone dipping downflow from the termination of the silt parting. The existence of primary Eh-pH gradient is indicated by a uranium-molybdenum zonation, the molybdenum lying above the uranium mineralization. The upper sandstone was an oxidizing fluvial channel in an arid environment through which uranyl carbonate was being transported in solution. Carbonaceous material undergoing anaerobic bacterial breakdown generated a weakly reducing fluid in the lower sandstone. Carbonaceous material at the REDOX front developed between the two mixing fluids at the point of sandstone coalescence reduced uranyl carbonates in solution. Once reduced the uranium minerals remained stable because the conditions in the REDOX front were only very weakly oxidizing. As floodplain aggradation continued, the upper sandstone was buried and the entire sandstone couplet became reducing, permanently stabilizing the uranium mineralization

Descriptive documentation for New Mexico uranium milling model

International Nuclear Information System (INIS)

Bonem, G.; Livevano, R.J.

1981-01-01

The New Mexico Uranium Milling Model is a linear programming model. It can demonstrate how cost minimizing management can reduce the costs of milling uranium subject to a series of environmental, resource, and technological constraints. For example, if 15,000 tons were the targeted level of milling output, the model would provide the minimum cost of this production level, given certain levels of environmental, fuel, water, and technological constraints. The model was developed to allow state policymakers to assess the uranium industry from various standpoints. Through the use of the model, state policymakers can determine the effects of air and water discharge standards and limited capital availability on: milling costs of production; uses of electricity, fuel, and water; and levels of air and water emissions. The model covers the following: process technologies which are acid leach and carbonate leach; raw materials mix; air and water discharges; residual treatment process; and plant types

Basis for the ICRP's age-specific biokinetic model for uranium

International Nuclear Information System (INIS)

Leggett, R.W.

1994-01-01

In an effort motivated largely by the Chernobyl nuclear accident, the International Commission on Radiological Protection (ICRP) is developing age-specific biokinetic models and dose coefficients for environmentally important radionuclides. This paper describes the ICRP's age-specific biokinetic model for uranium. The model is constructed within a physiologically based framework originally developed for application to the alkaline earth elements but sufficiently general to apply to the larger class of bone-volume-seeking elements. Transfer rates for a reference adult are based mainly on: (1) measurements of uranium in blood and excreta of several human subjects who were intravenously injected with uranium; (2) postmortem measurements of uranium in tissues of some of those subjects; (3) postmortem measurements of uranium in tissues of occupationally and non-occupationally exposed subjects; (4) data on baboons, dogs, and smaller laboratory animals exposed to uranium for experimental purposes; and (5) consideration of the physiological processes thought to control retention and translocation of uranium in the body. Transfer rates for the adult are extended to children by application of a set of generic assumptions applied by the ICRP to calcium-like elements. These assumptions were derived mainly from observations of the age-specific biokinetics of the alkaline earth elements and lead in humans and laboratory animals but are consistent with available age-specific biokinetic data on uranium. 82 refs., 17 figs., 8 tabs

Biokinetic models for the metabolism of uranium: an overview

International Nuclear Information System (INIS)

Bertelli, Luiz; Lipsztein, Joyce L.; Melo, Dunstana R.; Puerta, Anselmo; Wrenn, McDonald E.

1997-01-01

This work reviews the main experiments involving uranium injection and inhalation into several animal species and those associated with humans as well. The literature was carefully selected to involve the uranium intake, distribution and excretion in humans and mammals. The available biokinetic models for the uranium metabolism, proposed by ICRP in Publications 2, 30 and 69, were shortly described and tested against the data. Human data which incorporates measurements of urine, autopsy and biopsy samples were also used completing the review of models associated with the systemic part. (author). 21 refs., 4 figs

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

International Nuclear Information System (INIS)

Gomez, P.; Garralon, A.; Buil, B.; Turrero, Ma.J.; Sanchez, L.; Cruz, B. de la

2006-01-01

This paper describes the processes leading to uranium distribution in the groundwater of five boreholes near a restored uranium mine (dug in granite), and the environmental impact of restoration work in the discharge area. The groundwater uranium content varied from < 1 μg/L in reduced water far from the area of influence of the uranium ore-containing dyke, to 104 μg/L in a borehole hydraulically connected to the mine. These values, however, fail to reflect a chemical equilibrium between the water and the pure mineral phases. A model for the mobilization of uranium in this groundwater is therefore proposed. This involves the percolation of oxidized waters through the fractured granite, leading to the oxidation of pyrite and arsenopyrite and the precipitation of iron oxyhydroxides. This in turn leads to the dissolution of the primary pitchblende and, subsequently, the release of U(VI) species to the groundwater. These U(VI) species are retained by iron hydroxides. Secondary uranium species are eventually formed as reducing conditions are re-established due to water-rock interactions

Characterization of a U-Mo alloy subjected to direct hydriding of the gamma phase

International Nuclear Information System (INIS)

Balart, Silvia N.; Bruzzoni, Pablo; Granovsky, Marta S.

2003-01-01

The Reduced Enrichment for Research and Test Reactors (RERTR) program has imposed the need to develop plate-type fuel elements based on high density uranium compounds, such as U-Mo alloys. One of the steps in the fabrication of the fuel elements is the pulverization of the fissile material. In the case of the U-Mo alloys, the pulverization can be accomplished through hydriding - dehydriding. Two alternative methods of the hydriding-dehydriding process, namely the selective hydriding in alpha phase (HS-alpha) and the massive hydriding in gamma phase (HM-gamma) are currently being studied at the Comision Nacional de Energia Atomica. The HM-gamma method was reproduced at laboratory scale starting from a U-7 wt % Mo alloy. The hydrided and dehydrided materials were characterized using metallographic techniques, scanning electron microscopy, energy dispersive X-ray analysis and X-ray diffraction. These results are compared with previous results of the HS-alpha method. (author)

Lacustrine-humate model for primary uranium ore deposits, Grants Uranium Region, New Mexico

International Nuclear Information System (INIS)

Turner-Peterson, C.E.

1985-01-01

Two generations of uranium ore, primary and redistributed, occur in fluvial sandstones of the Upper Jurassic Morrison Formation in the San Juan basin; the two stages of ore formation can be related to the hydrologic history of the basin. Primary ore formed soon after Morrison deposition, in the Late Jurassic to Early Cretaceous, and a model, the lacustrine-humate model, is offered that views primary mineralization as a diagenetic event related to early pore fluid evolution. The basic premise is that the humate, a pore-filling organic material closely associated with primary ore, originated as humic acids dissolved in pore waters of greenish-gray lacustrine mudstones deposited in the mud-flat facies of the Brushy Basin Member and similar K shale beds in the Westwater Canyon Member. During compaction associated with early burial, formation water expelled from lacustrine mudstone units carried these humic acids into adjacent sandstone beds where the organics precipitated, forming the humate deposits that concentrated uranium. During the Tertiary, much later in the hydrologic history of the basin, when Jurassic sediments were largely compacted, oxygenated ground water flowed basinward from uplifted basin margins. This invasion of Morrison sandstone beds by oxidizing ground waters redistributed uranium from primary ores along redox boundaries, forming ore deposits that resemble roll-front-type uranium ores. 11 figures

Prediction of the net radon emission from a model open pit uranium mine

International Nuclear Information System (INIS)

Nielson, K.K.; Perkins, R.W.; Schwendiman, L.C.; Enderlin, W.I.

1979-04-01

Radon emission from a model open pit uranium mining operation has been estimated by applying radon exhalation fluxes measured in an open pit uranium mine to the various areas of the model mine. The model mine was defined by averaging uranium concentrations and production and procedural statistics for eight major open pit uranium mines in the Casper, Wyoming area. The resulting emission rates were 740 Ci/AFR during mining operations and 33 Ci/AFR/yr after abandonment of the mine

Models for estimating the radiation hazards of uranium mines

International Nuclear Information System (INIS)

Wise, K.N.

1982-01-01

Hazards to the health of workers in uranium mines derive from the decay products of radon and from uranium and its descendants. Radon daughters in mine atmospheres are either attached to aerosols or exist as free atoms and their physical state determines in which part of the lung the daughters deposit. The factors which influence the proportions of radon daughters attached to aerosols, their deposition in the lung and the dose received by the cells in lung tissue are discussed. The estimation of dose to tissue from inhalation or ingestion of uranium and daughters is based on a different set of models which have been applied in recent ICRP reports. The models used to describe the deposition of particulates, their movement in the gut and their uptake by organs, which form the basis for future limits on the concentration of uranium and daughters in air or on their intake with food, are outlined

Models for estimating the radiation hazards of uranium mines

International Nuclear Information System (INIS)

Wise, K.N.

1990-01-01

Hazards to the health of workers in uranium mines derive from the decay products of radon and from uranium and its descendants. Radon daughters in mine atmospheres are either attached to aerosols or exist as free atoms and their physical state determines in which part of the lung the daughters deposit. The factors which influence the proportions of radon daughters attached to aerosols, their deposition in the lung and the dose received by the cells in lung tissue are discussed. The estimation of dose to tissue from inhalation of ingestion or uranium and daughters is based on a different set of models which have been applied in recent ICRP reports. The models used to describe the deposition of particulates, their movement in the gut and their uptake by organs, which form the basis for future limits on the concentration of uranium and daughters in air or on their intake with food, are outlined. 34 refs., 12 tabs., 9 figs

A model of the world uranium market

International Nuclear Information System (INIS)

Trieu, L.H.; Savage, E.; Dwyer, G.

1994-01-01

In this paper the structure of the world uranium market is analysed and an econometric model developed. The modelling effort is focused on the spot market because developments in the spot market are increasingly being reflected in contract agreements and it is more transparent than the contract market. Changing surplus supplies of uranium on the spot market have led to wide variations in the spot price and this relationship is a focus of the analysis. The results indicate that stocks will reduce to a point where a gradual rise in spot prices can be expected after 1993 but the recovery will be sensitive to new supply entering from non-traditional market sources. (Author)

Research on interactive genetic-geological models to evaluate favourability for undiscovered uranium resources

International Nuclear Information System (INIS)

Finch, W.I.; Granger, H.C.; Lupe, R.; McCammon, R.B.

1980-01-01

Current methods of evaluating favourability for undiscovered uranium resources are unduly subjective, quite possibly inconsistent and, as a consequence, of questionable reliability. This research is aimed at reducing the subjectivity and increasing the reliability by designing an improved method that depends largely on geological data and their statistical frequency of occurrence. This progress report outlines a genetic approach to modelling the geological factors that controlled uranium mineralization in order to evaluate the favourability for the occurrence of undiscovered uranium deposits of the type modelled. A genetic model is constructed from all the factors that describe the processes, in chronological sequence, that formed uranium deposits thought to have a common origin. The field and laboratory evidence for the processes constitute a geologic-occurrence base that parallels the chronological sequence of events. The genetic model and the geologic-occurrence base are portrayed as two columns of an interactive matrix called the ''genetic-geologic model''. For each column, eight chronological stages are used to describe the overall formation of the uranium deposits. These stages consist of (1) precursor processes; (2) host-rock formation; (3) preparation of host-rock; (4) uranium-source development; (5) transport of uranium; (6) primary uranium deposition; (7) post-deposition modification; and (8) preservation. To apply the genetic-geological model to evaluate favourability, a question is posed that determines the presence or absence of each attribute listed under the geologic-occurrence base. By building a logic circuit of the attributes according to either their essential or non-essential nature, the resultant match between a well-documented control area and the test area may be determined. The degree of match is a measure of favourability for uranium occurrence as hypothesized in the genetic model

Distillation modeling for a uranium refining process

International Nuclear Information System (INIS)

Westphal, B.R.

1996-01-01

As part of the spent fuel treatment program at Argonne National Laboratory, a vacuum distillation process is being employed for the recovery of uranium following an electrorefining process. Distillation of a salt electrolyte, containing a eutectic mixture of lithium and potassium chlorides, from uranium is achieved by a simple batch operation and is termed open-quotes cathode processingclose quotes. The incremental distillation of electrolyte salt will be modeled by an equilibrium expression and on a molecular basis since the operation is conducted under moderate vacuum conditions. As processing continues, the two models will be compared and analyzed for correlation with actual operating results. Possible factors that may contribute to aberrations from the models include impurities at the vapor-liquid boundary, distillate reflux, anomalous pressure gradients, and mass transport phenomena at the evaporating surface. Ultimately, the purpose of either process model is to enable the parametric optimization of the process

Distillation modeling for a uranium refining process

Energy Technology Data Exchange (ETDEWEB)

Westphal, B.R.

1996-03-01

As part of the spent fuel treatment program at Argonne National Laboratory, a vacuum distillation process is being employed for the recovery of uranium following an electrorefining process. Distillation of a salt electrolyte, containing a eutectic mixture of lithium and potassium chlorides, from uranium is achieved by a simple batch operation and is termed {open_quotes}cathode processing{close_quotes}. The incremental distillation of electrolyte salt will be modeled by an equilibrium expression and on a molecular basis since the operation is conducted under moderate vacuum conditions. As processing continues, the two models will be compared and analyzed for correlation with actual operating results. Possible factors that may contribute to aberrations from the models include impurities at the vapor-liquid boundary, distillate reflux, anomalous pressure gradients, and mass transport phenomena at the evaporating surface. Ultimately, the purpose of either process model is to enable the parametric optimization of the process.

Deformation of wrought uranium: Experiments and modeling

Energy Technology Data Exchange (ETDEWEB)

McCabe, R.J., E-mail: rmccabe@lanl.gov [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Capolungo, L. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)] [UMI 2958 Georgia Tech - CNRS, 57070 Metz (France); Marshall, P.E.; Cady, C.M.; Tome, C.N. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2010-09-15

The room temperature deformation behavior of wrought polycrystalline uranium is studied using a combination of experimental techniques and polycrystal modeling. Electron backscatter diffraction is used to analyze the primary deformation twinning modes for wrought alpha-uranium. The {l_brace}1 3 0{r_brace}<3 1 0> twinning mode is found to be the most prominent twinning mode, with minor contributions from the '{l_brace}1 7 2{r_brace}'<3 1 2> and {l_brace}1 1 2{r_brace}'<3 7 2>' twin modes. Because of the large number of deformation modes, each with limited deformation systems, a polycrystalline model is employed to identify and quantify the activity of each mode. Model predictions of the deformation behavior and texture development agree reasonably well with experimental measures and provide reliable information about deformation systems.

A mathematical model to forecast uranium production

International Nuclear Information System (INIS)

Camisani-Calzolari, F.A.G.M.

1987-01-01

The uranium production forecasting program described in this paper projects production from reasonably assured, estimated additional and speculative resources in the cost categories of less than $130/kg U. Originally designed to handle South African production, it has been expanded and redimensioned using available published information to forecast production for countries of the Western World. The program forecasts production from up to 400 plants over a period of fifty years and has built-in production models derived from documented historical data of the more important uranium provinces. It is particularly suitable to assess production capabilities on a national and global scale where variations in outputs for the individual plants tend to even out. The program is aimed at putting the uranium potential of any one country into a realistic perspective, and it could thus be useful for planning purposes and marketing strategies

Improved ionic model of liquid uranium dioxide

NARCIS (Netherlands)

Gryaznov, [No Value; Iosilevski, [No Value; Yakub, E; Fortov, [No Value; Hyland, GJ; Ronchi, C

The paper presents a model for liquid uranium dioxide, obtained by improving a simplified ionic model, previously adopted to describe the equation of state of this substance [1]. A "chemical picture" is used for liquid UO2 of stoichiometric and non-stoichiometric composition. Several ionic species

Geochemical model of uranium and selenium in an aquifer disturbed by in situ uranium mining

International Nuclear Information System (INIS)

Johnson, K.; Neumann, M.R.

1986-01-01

Restoring ground water to baseline conditions proved to be very difficult, however, and led to the trial of a sodium carbonate/bicarbonate lixiviant. Results of this test indicated the basic lixiviant was unable to address uranium tied up in carbonaceous material. Subsequently, the decision was made to curtail development and restore all affected ground water to the extent achievable through the use of the best practicable technology, such as reverse osmosis. Restoration results, however, were not considered adequate for demonstration of commercial restoration feasibility. Following completion of the restoration effort, regulatory agencies expressed concern as to the long-term fate of certain parameters, such as uranium and selenium, remaining in solution at above baseline levels. Rocky Mountain Energy, through discussions with various consultants, determined that geochemical modeling would be the most appropriate tool for predicting the probable long-term effects. This paper summarizes the results of the subsequent evaluation which was conducted using the PHREEQE computer model. Significant conclusions of the investigation were: (1) the Eh in the ground water decreases regularly after mining activities, as shown by measured Eh values, and (2) the accompanying decrease in uranium and selenium can be predicted by thermodynamic modeling

Comparison of numerical and physico-chemical models for on-line spectrophotometric control of uranium

International Nuclear Information System (INIS)

Corriou, J.P.; Boisde, G.

1986-04-01

In view of on-line spectrophotometric control of fuel reprocessing streams, a physico-chemical model able to predict uranium and nitric acid concentrations in an uranyl nitrate-nitric acid system has been searched. Thus the influences of the following parameters: uranium, nitrate, hydrogen ion concentrations, ionic strength, on the equilibria of complexation of uranium (VI) nitrate have been evaluated. Extinction coefficients for the uranium mononitrate and uranium dinitrate complexes are given between 410 and 440 nm. The apparent equilibrium constants are determined as a function of the ionic strength. The limitations of this predictive model are emphasized and comparisons with numerical models are discussed. (16 refs)

A genetic model of progressively partial melting for uranium-bearing granites in south China

International Nuclear Information System (INIS)

Zhai Jianping.

1989-01-01

A genetic model of progressively partial and enrichment mechanism of uranium during partial melting of the sources of material studied and the significance of the genetic model in search of uranium deposits is elaborated. This model accounts better for some geological and geochemical features of uranium-bearing granties and suspects the traditional idea that igneous uranium-bearing granites were formed by fusion of U-rich strata surrounding these granites. Finally this paper points out that the infuence of U-rich strata of wall rocks of granites over uranium-bearing granites depends on variation of water solubility in the magma and assimilation of magma to wall rocks during its ascending and crystallization

Advances in the exploration model for Athabasca unconformity uranium deposits

International Nuclear Information System (INIS)

Wheatley, K.; Murphy, J.; Leppin, M.; Cutts, C.; Climie, J.A.

1997-01-01

This paper covers the genetic model of ore formation and exploration techniques Uranerz Exploration and Mining is presently using to explore for unconformity uranium deposits in the deeper parts of the Athabasca Basin. The main objectives of this paper are: 1) to present a genetic model for unconformity uranium deposits which is being used in our current exploration strategy, and 2) to present the sequence of exploration techniques used by Uranerz to explore for uranium in areas of the Athabasca Basin with up to 1000 m of sandstone cover. The Athabasca unconformity deposits are located in northern Saskatchewan, Canada. Within the Precambrian Athabasca Basin, exploration companies have discovered 18 uranium deposits. These contain more than 500 million kilograms of uranium, with average grades ranging from 0.3 to 12%. Uranerz discovered the Key Lake deposits in 1975, currently the largest and richest open pit uranium mine in the world. Uranerz also holds interests in the Rabbit Lake, Midwest Lake and McArthur River deposits, all in Saskatchewan, and is also actively exploring for uranium worldwide. The first discovery in the eastern Athabasca Basin was in 1968 at Rabbit Lake, followed by Key Lake in 1975. Both deposits had surficial indicators, such as radioactive boulders, strong geochemical anomalies in the surrounding lakes and swamps, and well-defined geophysical signatures. After the Key Lake discovery, an exploration model was devised which incorporated the underlying graphitic horizon and its strong electro-magnetic signature. Since then, there have been numerous new discoveries made by systematically drilling along these electro-magnetic conductors. The advancements in geophysical and geochemical techniques have led to discoveries at increasing depths. In 1988, the McArthur River deposit was discovered at a depth of 500 m. (author). 6 refs

On the mineralization model of 'three sources--heat, water and uranium'

International Nuclear Information System (INIS)

Li Xueli

1992-01-01

In response to the relations between geological and geothermal settings, geothermal water and uranium mineralizations in the Southeastern China, the model of uranium mineralization in discharge area (depressurization area) of fossil geothermal systems in Mesozoic-Cenozoic Volcanic-magmatic active areas has been put forward and expounded in the view of mineral-formation by the 'three sources'-heat, water and uranium

Geomigration model of uranium transfer

International Nuclear Information System (INIS)

Vasil'ev, I.A.; Ovchinnikov, N.A.; Chernov, V.V.; Shestakov, A.A.

2007-01-01

Data on geologic structure and radiation environment in the vicinity of the tailings storage facility (TSF) of Kara-Balta uranium hydrometallurgical factory in Kyrgyzstan were used to design a mathematical model of physical processes of wind erosion from the surface of TSF. Numerical calculations have been performed to describe prevalence of contamination due to wind erosion in the environs of Kara-Balta [ru

Uranium(VI) speciation: modelling, uncertainty and relevance to bioavailability models. Application to uranium uptake by the gills of a freshwater bivalve; Speciation de l'uranium(6), modelisation, incertitude et implication pour les modeles de biodisponibilite. Application a l'accumulation dans les branchies d'un bivalve d'eau douce

Energy Technology Data Exchange (ETDEWEB)

Denison, F.H

2004-07-01

The effects of varying solution composition on the interactions between uranium(VI) and excised gills of the freshwater bivalve Corbicula fluminea have been investigated in well defined solution media. A significant reduction in the uptake of uranium was observed on increasing the concentrations of the uranium complexing ligands citrate and carbonate. Saturation kinetics as a function of uranium concentration at a pH value of 5.0 were observed, indicating that the uptake of uranium is a facilitated process, probably involving one or several trans-membrane transport systems. A relatively small change in the uptake of uranium was found as a function of pH (factor of ca. 2), despite the extremely large changes to the solution speciation of uranium within the range of pH investigated (5.0 - 7.5). A comprehensive review of the thermodynamic data relevant to the solution composition domain employed for this study was performed. Estimates of the uncertainties for the formation constants of aqueous uranium(VI) species were integrated into a thermodynamic database. A computer program was written to predict the equilibrium distribution of uranium(VI) in simple aqueous systems, using thermodynamic parameter mean-values. The program was extended to perform Monte Carlo and Quasi Monte Carlo uncertainty analyses, incorporating the thermodynamic database uncertainty estimates, to quantitatively predict the uncertainties inherent in predicting the solution speciation of uranium. The use of thermodynamic equilibrium modelling as a tool for interpreting the bioavailability of uranium(VI) was investigated. Observed uranium(VI) uptake behaviour was interpreted as a function of the predicted changes to the solution speciation of uranium. Different steady-state or pre-equilibrium approaches to modelling uranium uptake were tested. Alternative modelling approaches were also tested, considering the potential changes to membrane transport system activity or sorption characteristics on

The Namibian uranium mining model

International Nuclear Information System (INIS)

Swiegers, Wotan; Tibinyane, Axel

2014-01-01

Conclusions: • Namibia wishes to be a world class producer of Uranium and a prosperous country to achieve the Nation’s 2030 Vision. • The Government and the Uranium Industry formed a Smart Partnership to protect our ‘Brand’. • The Government and the Uranium Industry are committed to implement ‘world best practices’. • Namibia will be guided by the IAEA and the WNA.

PEMBUATAN SERBUK U-6Zr DENGAN PENGKAYAAN URANIUM 19,75 % UNTUK BAHAN BAKAR REAKTOR RISET

Directory of Open Access Journals (Sweden)

Masrukan Masrukan

2016-03-01

Full Text Available ABSTRAK PEMBUATAN SERBUK PADUAN U-6Zr DENGAN PENGKAYAAN URANIUM 19,75 % UNTUK BAHAN BAKAR REAKTOR RISET. Telah dilakukan pembuatan serbuk paduan U-6Zr dengan pengkayaan 19,75 % untuk bahan bakar reaktor riset. Pembuatan bahan bakar U-6Zr ini dalam rangka mencari bahan bakar baru yang mempunyai densitas tinggi untuk mengganti bahan bakar yang sudah ada U3Si2-Al. Tujuan dari percobaan ini untuk mengetahui sifat-sifat serbuk paduan U- 6Zr yang diperoleh dari proses hydriding-dehydriding sebagai kandidat bahan bakar reaktor riset. Serbuk yang diperoleh dari proses hydriding-dehydriding dikenai pengujian, diantaranya pungujian komposisi kimia, densitas, kandungan hidrogen, fasa dan sifat termal. Hasil pengujian komposisi kimia menunjukkan beberapa unsur seperti Al, Ca, Cu, dan Ni melebihi batas yang diijinkan dimana masing-masing unsur terdapat sebesar 202,21 ppm; 214,05 ppm; 61,25 ppm dan 134,53 ppm. Pada pengujian diperolah densitas serbuk U-6Zr sebesar 13,58 g/cm3 dan pada pengujian kandungan hidrogen sisa diperoleh kandungan hidrogen sebesar 0,16 %. Untuk pengujian fasa, diperoleh fasa αU dan δU, sedangkan pada pengujian sifat termal yakni transformasi temperatur terdapat dua puncak yakni puncak pertama terjadi pada temperatur 274 hingga 311 oC dan puncak kedua terjadi pada temperatur 493 hingga 527oC. Puncak pertama terjadi reaksi endotermik dengan menyerap panas sebesar ∆H = 6,23 cal/g tetapi tidak terbentuk fasa baru, sedangkan puncak kedua terjadi reaksi eksotermik dengan mengeluarkan panas sebesar ∆H = -9.34 cal/g dan terbentuk fasa αZr. Sementara itu, dari pengujian kapasitas panas pada temperatur 34 hingga 75 oC, terjadinya penurunan nilai kapasitas panas yang disertai dengan penyerapan panas. Pada temperatur yang lebih tinggi hingga temperatur 437oC nilai kapasitas panas menjadi lebih kecil disertai pengeluaran panas. Reaksi termokimia antara Zr dengan hidrogen sisa menunjukkan terbentuknya fasa αZr yang diindikasikan oleh reaksi

Prediction of the net radon emission from a model open pit uranium mine

International Nuclear Information System (INIS)

Nielson, K.K.; Perkins, R.W.; Schwendiman, L.C.; Enderlin, W.I.

1979-09-01

Radon emission from a model open pit uranium mining operation has been estimated by applying radon exhalation fluxes measured in an open pit uranium mine to the various areas of the model mine. The model mine was defined by averaging uranium concentrations, mine dimensions, production and procedural statistics for eight major open pit uranium mines in the Casper, Wyoming area. The resulting emission rates were 630 Ci/RRY (1 RRY one = 1000-MW(e) reactor operating for 1 year) during mining operations and 26 Ci/RRY/y after abandoment of the mine assuming 100% recovery of U 3 O 8 from the ore, or 700 Ci/RRY and 29 Ci/RRY/y assuming 90.5% recovery

Scaling up the production capacity of U-Mo powder by HMD process

International Nuclear Information System (INIS)

Pasqualini, E.E.; Lopez, M.; Helzel Garcia, L.J.; Echenique, P.; Adelfang, P.

2002-01-01

The recent discovery that uranium alloys in metastable gamma phase can be hydrided at low temperatures and pressures have allowed developing the method of commuting bulk materials by milling the hydride to desired size and then dehydriding the powder. This process is called HMD (hydriding-milling-dehydriding) and needs an initial step of hydrogen incorporation to allow the alloy to be hydrided. This four step process has been conveniently set up for the production of U-7Mo powder for its use in nuclear fuels. Low equipment investment and low man power are needed for this achievement. The process is being analyzed in its scaling up for one kilogram batches and a 50 kilogram per year production capacity of U-Mo powder. (author)

Modeled atmospheric radon concentrations from uranium mines

Energy Technology Data Exchange (ETDEWEB)

Droppo, J.G.

1985-04-01

Uranium mining and milling operations result in the release of radon from numerous sources of various types and strengths. The US Environmental Protection Agency (EPA) under the Clean Air Act, is assessing the health impact of air emissions of radon from underground uranium mines. In this case, the radon emissions may impact workers and residents in the mine vicinity. To aid in this assessment, the EPA needs to know how mine releases can affect the radon concentrations at populated locations. To obtain this type of information, Pacific Northwest Laboratory used the radon emissions, release characteristics and local meterological conditions for a number of mines to model incremental radon concentrations. Long-term, average, incremental radon concentrations were computed based on the best available information on release rates, plume rise parameters, number and locations of vents, and local dispersion climatology. Calculations are made for a model mine, individual mines, and multiple mines. Our approach was to start with a general case and then consider specific cases for comparison. A model underground uranium mine was used to provide definition of the order of magnitude of typical impacts. Then computations were made for specific mines using the best mine-specific information available for each mine. These case study results are expressed as predicted incremental radon concentration contours plotted on maps with local population data from a previous study. Finally, the effect of possible overlap of radon releases from nearby mines was studied by calculating cumulative radon concentrations for multiple mines in a region with many mines. The dispersion model, modeling assumptions, data sources, computational procedures, and results are documented in this report. 7 refs., 27 figs., 18 tabs.

Modeled atmospheric radon concentrations from uranium mines

International Nuclear Information System (INIS)

Droppo, J.G.

1985-04-01

Uranium mining and milling operations result in the release of radon from numerous sources of various types and strengths. The US Environmental Protection Agency (EPA) under the Clean Air Act, is assessing the health impact of air emissions of radon from underground uranium mines. In this case, the radon emissions may impact workers and residents in the mine vicinity. To aid in this assessment, the EPA needs to know how mine releases can affect the radon concentrations at populated locations. To obtain this type of information, Pacific Northwest Laboratory used the radon emissions, release characteristics and local meterological conditions for a number of mines to model incremental radon concentrations. Long-term, average, incremental radon concentrations were computed based on the best available information on release rates, plume rise parameters, number and locations of vents, and local dispersion climatology. Calculations are made for a model mine, individual mines, and multiple mines. Our approach was to start with a general case and then consider specific cases for comparison. A model underground uranium mine was used to provide definition of the order of magnitude of typical impacts. Then computations were made for specific mines using the best mine-specific information available for each mine. These case study results are expressed as predicted incremental radon concentration contours plotted on maps with local population data from a previous study. Finally, the effect of possible overlap of radon releases from nearby mines was studied by calculating cumulative radon concentrations for multiple mines in a region with many mines. The dispersion model, modeling assumptions, data sources, computational procedures, and results are documented in this report. 7 refs., 27 figs., 18 tabs

Potential supply system for uranium based upon a crustal abundance model

International Nuclear Information System (INIS)

Chavez-Martinez, M.L.

1982-01-01

The design of a computerized system for the estimation of uranium potential supply in the US was the primary objective of this study. Once completed, this system performs for various levels of economic variables, such as prices and estimation of potential uranium supply, without requiring the appraisal by geologists, area by area, of undiscovered uranium endowment. The main components that form the system are explicit models of endowment, exploration, and production. These component models are derived from engineering and geological data, and together, they comprise the system. This system is unique in that it likes physical attributes of endowment to time series of price and production. This linkage is made by simulating the activities of the US uranium industry, activities (exploration, mine development, and production) that are involved in the transformation of endowment to potential supply

Modelling of redox front and uranium movement in a uranium mine at Pocos de Caldas, Brazil

International Nuclear Information System (INIS)

Cross, J.E.; Gabriel, D.S.; Haworth, A.; Sharland, S.M.; Tweed, C.J.

1991-04-01

A study of the migration of uranium at the Pocos de Caldas uranium mine in Brazil under the influence of the infiltration of oxidising groundwaters has been performed. The modelling was carried out using the coupled chemical equilibria/transport code CHEQMATE. The work presented in this paper extends a previous study. Results give some encouraging agreements with field data, generally increasing confidence in the use of such modelling techniques in problems associated with the migration of radionuclides away from a nuclear waste repository. For particular aspects of the problem where good agreement with field data was not obtained, a number of reasons have been suggested. This study also highlights the importance of accurate thermodynamic data and choice of solubility-limiting mineral phases for modelling such systems. (author)

Development of a program in LABVIEW platform to controlling and monitoring a Sievert-type system for comminution of metallic uranium and its alloys

International Nuclear Information System (INIS)

Dutra, Aimore R.R.; Ferraz, Wilmar B.; Ferreira, Ricardo A.N.

2011-01-01

A comminution process by hydriding-dehydriding method was developed at CDTN-Centro de Desenvolvimento da Tecnologia Nuclear with the purpose of obtaining plate type nuclear fuel. This fuel requires the use of metallic uranium and its alloys in form of powders. This comminution process was performed based on a Sievert system. Initially this system was controlled and monitored by a computer program developed in Turbo Pascal language. In order to improve the control of the comminution process, a new program was developed in LabVIEW platform. This paper presents a description of this new program and the main aspects of the operation of the system. The more accurate monitoring and controlling of the various stages of the comminution process as well as greater flexibility in the choice of input data, real-time graphics, generation of reports and a reduction of time passivation were achieved. (author)

Development of a program in LABVIEW platform to controlling and monitoring a Sievert-type system for comminution of metallic uranium and its alloys

Energy Technology Data Exchange (ETDEWEB)

Dutra, Aimore R.R.; Ferraz, Wilmar B.; Ferreira, Ricardo A.N., E-mail: ferrazw@cdtn.b, E-mail: ranf@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2011-07-01

A comminution process by hydriding-dehydriding method was developed at CDTN-Centro de Desenvolvimento da Tecnologia Nuclear with the purpose of obtaining plate type nuclear fuel. This fuel requires the use of metallic uranium and its alloys in form of powders. This comminution process was performed based on a Sievert system. Initially this system was controlled and monitored by a computer program developed in Turbo Pascal language. In order to improve the control of the comminution process, a new program was developed in LabVIEW platform. This paper presents a description of this new program and the main aspects of the operation of the system. The more accurate monitoring and controlling of the various stages of the comminution process as well as greater flexibility in the choice of input data, real-time graphics, generation of reports and a reduction of time passivation were achieved. (author)

Global Modeling of Uranium Molecular Species Formation Using Laser-Ablated Plasmas

Science.gov (United States)

Curreli, Davide; Finko, Mikhail; Azer, Magdi; Armstrong, Mike; Crowhurst, Jonathan; Radousky, Harry; Rose, Timothy; Stavrou, Elissaios; Weisz, David; Zaug, Joseph

2016-10-01

Uranium is chemically fractionated from other refractory elements in post-detonation nuclear debris but the mechanism is poorly understood. Fractionation alters the chemistry of the nuclear debris so that it no longer reflects the chemistry of the source weapon. The conditions of a condensing fireball can be simulated by a low-temperature plasma formed by vaporizing a uranium sample via laser heating. We have developed a global plasma kinetic model in order to model the chemical evolution of U/UOx species within an ablated plasma plume. The model allows to track the time evolution of the density and energy of an uranium plasma plume moving through an oxygen atmosphere of given fugacity, as well as other relevant quantities such as average electron and gas temperature. Comparison of model predictions with absorption spectroscopy of uranium-ablated plasmas provide preliminary insights on the key chemical species and evolution pathways involved during the fractionation process. This project was sponsored by the DoD, Defense Threat Reduction Agency, Grant HDTRA1-16-1-0020. This work was performed in part under the auspices of the U.S. DoE by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Discussion on geochemical characteristics, mechanism and prospecting model of gluey type sandstone uranium mineralization--taking Redwell uranium deposit as an example

International Nuclear Information System (INIS)

Wang Jinping

1998-01-01

Redwell uranium deposit hosted in the red clastic rock formation, is a typical example of gluey type uranium mineralization, which has not been reported so far in China. Based on the study of geochemical characteristics of Redwell deposit, the author discusses the genetic mechanism of this type deposits, and proposes the prospecting model of 4 in 1 of red bed-fault-oil gas-uranium source

Main geologic characteristics and metallogenic models of uranium deposits in Zhejiang

International Nuclear Information System (INIS)

Tang Qitao

2000-01-01

Uranium resources in Zhejiang is abundant with numerous mineralization types. According to the genesis they can be classified into: sedimentary-reworking type, hydrothermal type and infiltration type. The author briefly describes main geologic characteristics and metallogenic models of different type uranium deposits

Time delay and profit accumulation effect on a mine-based uranium market clearing model

International Nuclear Information System (INIS)

Auzans, Aris; Teder, Allan; Tkaczyk, Alan H.

2016-01-01

Highlights: • Improved version of a mine-based uranium market clearing model for the front-end uranium market and enrichment industries is proposed. • A profit accumulation algorithm and time delay function provides more realistic uranium mine decision making process. • Operational decision delay increased uranium market price volatility. - Abstract: The mining industry faces a number of challenges such as market volatility, investment safety, issues surrounding employment and productivity. Therefore, computer simulations are highly relevant in order to reduce financial risks associated with these challenges. In the mining industry, each firm must compete with other mines and the basic target is profit maximization. The aim of this paper is to evaluate the world uranium (U) supply by simulating financial management challenges faced by an individual U mine that are caused by a variety of regulation issues. In this paper front-end nuclear fuel cycle tool is used to simulate market conditions and the effects they have on the stability of U supply. An individual U mine’s exit or entry in the market might cause changes in the U supply side which can increase or decrease the market price. In this paper we offer a more advanced version of a mine-based U market clearing model. The existing U market model incorporates the market of primary U from uranium mines with secondary uranium (depleted uranium DU), enriched uranium (HEU) and enrichment services. In the model each uranium mine acts as an independent agent that is able to make operational decisions based on the market price. This paper introduces a more realistic decision making algorithm of individual U mine that adds constraints to production decisions. The authors added an accumulated profit model, which allows for the profits accumulated to cover any possible future economic losses and the time-delay algorithm to simulate delayed process of reopening a U mine. The U market simulation covers time period 2010

Time delay and profit accumulation effect on a mine-based uranium market clearing model

Energy Technology Data Exchange (ETDEWEB)

Auzans, Aris [Institute of Physics, University of Tartu, Ostwaldi 1, EE-50411 Tartu (Estonia); Teder, Allan [School of Economics and Business Administration, University of Tartu, Narva mnt 4, EE-51009 Tartu (Estonia); Tkaczyk, Alan H., E-mail: alan@ut.ee [Institute of Physics, University of Tartu, Ostwaldi 1, EE-50411 Tartu (Estonia)

2016-12-15

Highlights: • Improved version of a mine-based uranium market clearing model for the front-end uranium market and enrichment industries is proposed. • A profit accumulation algorithm and time delay function provides more realistic uranium mine decision making process. • Operational decision delay increased uranium market price volatility. - Abstract: The mining industry faces a number of challenges such as market volatility, investment safety, issues surrounding employment and productivity. Therefore, computer simulations are highly relevant in order to reduce financial risks associated with these challenges. In the mining industry, each firm must compete with other mines and the basic target is profit maximization. The aim of this paper is to evaluate the world uranium (U) supply by simulating financial management challenges faced by an individual U mine that are caused by a variety of regulation issues. In this paper front-end nuclear fuel cycle tool is used to simulate market conditions and the effects they have on the stability of U supply. An individual U mine’s exit or entry in the market might cause changes in the U supply side which can increase or decrease the market price. In this paper we offer a more advanced version of a mine-based U market clearing model. The existing U market model incorporates the market of primary U from uranium mines with secondary uranium (depleted uranium DU), enriched uranium (HEU) and enrichment services. In the model each uranium mine acts as an independent agent that is able to make operational decisions based on the market price. This paper introduces a more realistic decision making algorithm of individual U mine that adds constraints to production decisions. The authors added an accumulated profit model, which allows for the profits accumulated to cover any possible future economic losses and the time-delay algorithm to simulate delayed process of reopening a U mine. The U market simulation covers time period 2010

Characteristics and model of sandstone type uranium deposit in south of Songliao basin

International Nuclear Information System (INIS)

Yu Wenbin; Yu Zhenqing

2010-01-01

Through analyzing the uranium deposit tectonic environment, upper cretaceous sequence stratigraphy, depositional system, evolutionary characteristics of sand bodies, the effect of subsequent transformation and the characteristic of uranium deposit, the sandstone type uranium deposit in southern basin is different from typical interlayer oxidation zone sandstone type uranium deposit. The formation and evolution of sandstone-type uranium deposit are controlled by structure fensters; the favorable sedimentary facies type is braided river facies, and the ore body is braided river sand body. The size of uranium deposits is controlled by the local oxidation zone with the characteristics of sandstone type uranium deposit in partial oxidation zone. Uranium ore bodies which distribute in the roof wings of structure fenstes, and occur in gray layers between the upper and lower oxidation zone, showing tabular, and the plate of uranium ore body is controlled by the local oxidation zone. Based on the geological features of sandstone-type uranium deposits, the metallogenic model of local oxidation zones sandstone-type uranium deposits has been set up in the south of Songliao Baisn. (authors)

Modelling a uranium ore bioleaching process

International Nuclear Information System (INIS)

Chien, D.C.H.; Douglas, P.L.; Herman, D.H.; Marchbank, A.

1990-01-01

A dynamic simulation model for the bioleaching of uranium ore in a stope leaching process has been developed. The model incorporates design and operating conditions, reaction kinetics enhanced by Thiobacillus ferroxidans present in the leaching solution and transport properties. Model predictions agree well with experimental data with an average deviation of about ± 3%. The model is sensitive to small errors in the estimates of fragment size and ore grade. Because accurate estimates are difficult to obtain a parameter estimation approach was developed to update the value of fragment size and ore grade using on-line plant information

Pharmacokinetic models relevant to toxicity and metabolism for uranium in humans and animals

International Nuclear Information System (INIS)

Wrenn, M.E.; Lipsztein, J.; Bertelli, L.

1988-01-01

The aim of this paper is to summarize pharmacokinetic models of uranium metabolism. Fortunately, others have recently reviewed metabolic models of all types, not just pharmacokinetic models. Their papers should be consulted for greater biological detail than is possible here. Improvements in the models since these other papers are noted. Models for assessing the biological consequences of exposure should account for the kinetics of intake by ingestion, inhalation, and injection, and the chemical form of uranium; predict the time dependent concentration in red blood cells, plasma, urine, kidney, bone and other organs (or compartments); and be adaptable to calculating these concentrations for varying regimens of intake. The biological parameters in the models come from metabolic data in humans and animals. Some of these parameters are reasonably well defined. For example, the cumulative urinary excretion at 24 hours post injection of soluble uranium in man is about 70%, the absorbed fraction for soluble uranium ingested by man in drinking water during normal dietary conditions is about 1%, and the half time in the mammalian kidney is several days. 17 refs., 8 figs

A model of early formation of uranium molecular oxides in laser-ablated plasmas

Science.gov (United States)

Finko, Mikhail; Curreli, Davide; Azer, Magdi; Weisz, David; Crowhurst, Jonathan; Rose, Timothy; Koroglu, Batikan; Radousky, Harry; Zaug, Joseph; Armstrong, Mike

2017-10-01

An important problem within the field of nuclear forensics is fractionation: the formation of post-detonation nuclear debris whose composition does not reflect that of the source weapon. We are investigating uranium fractionation in rapidly cooling plasma using a combined experimental and modeling approach. In particular, we use laser ablation of uranium metal samples to produce a low-temperature plasma with physical conditions similar to a condensing nuclear fireball. Here we present a first plasma-chemistry model of uranium molecular species formation during the early stage of laser ablated plasma evolution in atmospheric oxygen. The system is simulated using a global kinetic model with rate coefficients calculated according to literature data and the application of reaction rate theory. The model allows for a detailed analysis of the evolution of key uranium molecular species and represents the first step in producing a uranium fireball model that is kinetically validated against spatially and temporally resolved spectroscopy measurements. This project was sponsored by the DoD, Defense Threat Reduction Agency, Grant HDTRA1-16- 1-0020. This work was performed in part under the auspices of the U.S. DoE by Lawrence Livermore National Laboratory under Contract DE-AC52- 07NA27344.

Statistical model for forecasting uranium prices to estimate the nuclear fuel cycle cost

International Nuclear Information System (INIS)

Kim, Sung Ki; Ko, Won Il; Nam, Hyoon; Kim, Chul Min; Chung, Yang Hon; Bang, Sung Sig

2017-01-01

This paper presents a method for forecasting future uranium prices that is used as input data to calculate the uranium cost, which is a rational key cost driver of the nuclear fuel cycle cost. In other words, the statistical autoregressive integrated moving average (ARIMA) model and existing engineering cost estimation method, the so-called escalation rate model, were subjected to a comparative analysis. When the uranium price was forecasted in 2015, the margin of error of the ARIMA model forecasting was calculated and found to be 5.4%, whereas the escalation rate model was found to have a margin of error of 7.32%. Thus, it was verified that the ARIMA model is more suitable than the escalation rate model at decreasing uncertainty in nuclear fuel cycle cost calculation

Statistical model for forecasting uranium prices to estimate the nuclear fuel cycle cost

Energy Technology Data Exchange (ETDEWEB)

Kim, Sung Ki; Ko, Won Il; Nam, Hyoon [Nuclear Fuel Cycle Analysis, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Chul Min; Chung, Yang Hon; Bang, Sung Sig [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

2017-08-15

This paper presents a method for forecasting future uranium prices that is used as input data to calculate the uranium cost, which is a rational key cost driver of the nuclear fuel cycle cost. In other words, the statistical autoregressive integrated moving average (ARIMA) model and existing engineering cost estimation method, the so-called escalation rate model, were subjected to a comparative analysis. When the uranium price was forecasted in 2015, the margin of error of the ARIMA model forecasting was calculated and found to be 5.4%, whereas the escalation rate model was found to have a margin of error of 7.32%. Thus, it was verified that the ARIMA model is more suitable than the escalation rate model at decreasing uncertainty in nuclear fuel cycle cost calculation.

A biokinetic and dosimetric model for the metabolism of uranium

International Nuclear Information System (INIS)

Wrenn, M.E.; Bertelli, L.; Durbin, P.W.; Eckerman, K.F.; Lipsztein, J.L.; Singh, N.P.

1995-10-01

Experiments involving injection and inhalation of uranium compounds into several animal species as well as those associated with humans are described and analyzed. A revised biokinetic and dosimetric model for the metabolism of uranium suitable for bioassay procedures is proposed. The model consists of a systematic part coupled to a model of the respiratory tract. The model has been tested against human data which incorporates in vivo measurements over the chest and measurements of urine, feces, and autopsy and biopsy samples.In particular the lung model of the International Commission on Radiological Protection, Publication 30 ( ICRP-30 ), has been modified in order to provide a model which more nearly predicts urinary excretion in accord with the experiences in humans and animals. We have also tested the data against the new ICRP (LUDEP) lung model. (author). 55 refs., 14 tabs., 33 figs

Solubility measurement of uranium in uranium-contaminated soils

International Nuclear Information System (INIS)

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

1993-08-01

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

Precambrian uranium-bearing quartz-pebble conglomerates: exploration model and United States resource potential

International Nuclear Information System (INIS)

Houston, R.S.; Karlstrom, K.E.

1979-11-01

Uranium has been discovered in fluvial quartz-pebble conglomerates in most of the Precambrian shield areas of the world, including the Canadian, African, South American, Indian, Baltic, and Australian shields. Occurrences in these and other areas are shown. Two of these occurrences, the Huronian supergroup of Canada and the Witwatersrand deposit of South Africa contain 20 to 30 percent of the planet's known uranium reserves. Thus it is critical that we understand the origin of these deposits and develop exploration models that can aid in finding new deposits. Inasmuch as these uranium-bearing conglomerates are confined almost entirely to rocks of Precambrian age, Part I of this review begins with a discussion of Precambrian geology as it applies to the conglomerates. This is followed by a discussion of genetic concepts, a discussion of unresolved problems, and finally a suggested exploration model. Part II summarizes known and potential occurrences of Precambrian fossil placers in the world and evaluates them in terms of the suggested exploration model. Part III discusses the potential for important Precambrian fossil-placer uranium deposits in the United States and includes suggestions that may be helpful in establishing an exploration program in this country. Part III also brings together new (1975-1978) data on uranium occurrences in the Precambrian of the Wyoming Province. Part IV is a complete bibliography of Precambrian fossil placers, divided according to geographical areas. In total, this paper is designed to be a comprehensive review of Precambrian uranium-bearing fossil placers which will be of use to uranium explorationists and to students of Precambrian geology

Precambrian uranium-bearing quartz-pebble conglomerates: exploration model and United States resource potential

Energy Technology Data Exchange (ETDEWEB)

Houston, R.S.; Karlstrom, K.E.

1979-11-01

Uranium has been discovered in fluvial quartz-pebble conglomerates in most of the Precambrian shield areas of the world, including the Canadian, African, South American, Indian, Baltic, and Australian shields. Occurrences in these and other areas are shown. Two of these occurrences, the Huronian supergroup of Canada and the Witwatersrand deposit of South Africa contain 20 to 30 percent of the planet's known uranium reserves. Thus it is critical that we understand the origin of these deposits and develop exploration models that can aid in finding new deposits. Inasmuch as these uranium-bearing conglomerates are confined almost entirely to rocks of Precambrian age, Part I of this review begins with a discussion of Precambrian geology as it applies to the conglomerates. This is followed by a discussion of genetic concepts, a discussion of unresolved problems, and finally a suggested exploration model. Part II summarizes known and potential occurrences of Precambrian fossil placers in the world and evaluates them in terms of the suggested exploration model. Part III discusses the potential for important Precambrian fossil-placer uranium deposits in the United States and includes suggestions that may be helpful in establishing an exploration program in this country. Part III also brings together new (1975-1978) data on uranium occurrences in the Precambrian of the Wyoming Province. Part IV is a complete bibliography of Precambrian fossil placers, divided according to geographical areas. In total, this paper is designed to be a comprehensive review of Precambrian uranium-bearing fossil placers which will be of use to uranium explorationists and to students of Precambrian geology.

Toxicity of Depleted Uranium Dust Particles: Results of a New Model

International Nuclear Information System (INIS)

Zucchetti, M.

2013-01-01

Depleted uranium (DU) is mostly composed of U-238, a naturally radioactive isotope. Concerning chemical toxicity, uranium, being a heavy metal, is known to have toxic effects on specific organs in the body, the kidneys in particular. Its effects are similar to those of other heavy metals, such as lead and cadmium. Scientific evidence resulting both from in vitro and in vivo analyses shows that current models of the mechanisms of toxicity of uranium dust are not fully satisfactory. They should be refined in order to obtain more effective responses and predictions regarding health effects. In particular, radiotoxicity potential of Depleted Uranium dust originated by military use of this material for ammunition must be re-evaluated taking into account the bystander effect, the dose enhancing effect and other minor phenomena. Uranium dust has both chemical and radiological toxicity: the synergistic aspect of the two effects has to be accounted for, in order to arrive to a complete description of the phenomenon. The combination of the two different toxicities (chemical and radiological) of depleted uranium is attempted here for the first time, approaching the long-term effects of Depleted Uranium, and in particular the carcinogenetic effects. A case study (Balkan war, 1999) is discussed. (Author)

Statistical model of global uranium resources and long-term availability

International Nuclear Information System (INIS)

Monnet, A.; Gabriel, S.; Percebois, J.

2016-01-01

Most recent studies on the long-term supply of uranium make simplistic assumptions on the available resources and their production costs. Some consider the whole uranium quantities in the Earth's crust and then estimate the production costs based on the ore grade only, disregarding the size of ore bodies and the mining techniques. Other studies consider the resources reported by countries for a given cost category, disregarding undiscovered or unreported quantities. In both cases, the resource estimations are sorted following a cost merit order. In this paper, we describe a methodology based on 'geological environments'. It provides a more detailed resource estimation and it is more flexible regarding cost modelling. The global uranium resource estimation introduced in this paper results from the sum of independent resource estimations from different geological environments. A geological environment is defined by its own geographical boundaries, resource dispersion (average grade and size of ore bodies and their variance), and cost function. With this definition, uranium resources are considered within ore bodies. The deposit breakdown of resources is modelled using a bivariate statistical approach where size and grade are the two random variables. This makes resource estimates possible for individual projects. Adding up all geological environments provides a distribution of all Earth's crust resources in which ore bodies are sorted by size and grade. This subset-based estimation is convenient to model specific cost structures. (authors)

Texas Panhandle soil-crop-beef food chain for uranium: a dynamic model validated by experimental data

International Nuclear Information System (INIS)

Wenzel, W.J.; Wallwork-Barber, K.M.; Rodgers, J.C.; Gallegos, A.F.

1982-01-01

Long-term simulations of uranium transport in the soil-crop-beef food chain were performed using the BIOTRAN model. Experimental data means from an extensive Pantex beef cattle study are presented. Experimental data were used to validate the computer model. Measurements of uranium in air, soil, water, range grasses, feed, and cattle tissues are compared to simulated uranium output values in these matrices when the BIOTRAN model was set at the measured soil and air values. The simulations agreed well with experimental data even though metabolic details for ruminants and uranium chemical form in the environment remain to be studied

Controlling intake of uranium in the workplace: Applications of biokinetic modeling and occupational monitoring data

Energy Technology Data Exchange (ETDEWEB)

Leggett, Richard Wayne [ORNL; Eckerman, Keith F [ORNL; McGinn, Wilson [ORNL; Meck, Dr. Robert A. [U.S. Nuclear Regulatory Commission

2012-01-01

This report provides methods for interpreting and applying occupational uranium monitoring data. The methods are based on current international radiation protection guidance, current information on the chemical toxicity of uranium, and best available biokinetic models for uranium. Emphasis is on air monitoring data and three types of bioassay data: the concentration of uranium in urine; the concentration of uranium in feces; and the externally measured content of uranium in the chest. Primary Reference guidance levels for prevention of chemical effects and limitation of radiation effects are selected based on a review of current scientific data and regulatory principles for setting standards. Generic investigation levels and immediate action levels are then defined in terms of these primary guidance levels. The generic investigation and immediate actions levels are stated in terms of radiation dose and concentration of uranium in the kidneys. These are not directly measurable quantities, but models can be used to relate the generic levels to the concentration of uranium in air, urine, or feces, or the total uranium activity in the chest. Default investigation and immediate action levels for uranium in air, urine, feces, and chest are recommended for situations in which there is little information on the form of uranium taken into the body. Methods are prescribed also for deriving case-specific investigation and immediate action levels for uranium in air, urine, feces, and chest when there is sufficient information on the form of uranium to narrow the range of predictions of accumulation of uranium in the main target organs for uranium: kidneys for chemical effects and lungs for radiological effects. In addition, methods for using the information herein for alternative guidance levels, different from the ones selected for this report, are described.

Factoring uncertainty into restoration modeling of in-situ leach uranium mines

Science.gov (United States)

Johnson, Raymond H.; Friedel, Michael J.

2009-01-01

Postmining restoration is one of the greatest concerns for uranium in-situ leach (ISL) mining operations. The ISL-affected aquifer needs to be returned to conditions specified in the mining permit (either premining or other specified conditions). When uranium ISL operations are completed, postmining restoration is usually achieved by injecting reducing agents into the mined zone. The objective of this process is to restore the aquifer to premining conditions by reducing the solubility of uranium and other metals in the ground water. Reactive transport modeling is a potentially useful method for simulating the effectiveness of proposed restoration techniques. While reactive transport models can be useful, they are a simplification of reality that introduces uncertainty through the model conceptualization, parameterization, and calibration processes. For this reason, quantifying the uncertainty in simulated temporal and spatial hydrogeochemistry is important for postremedial risk evaluation of metal concentrations and mobility. Quantifying the range of uncertainty in key predictions (such as uranium concentrations at a specific location) can be achieved using forward Monte Carlo or other inverse modeling techniques (trial-and-error parameter sensitivity, calibration constrained Monte Carlo). These techniques provide simulated values of metal concentrations at specified locations that can be presented as nonlinear uncertainty limits or probability density functions. Decisionmakers can use these results to better evaluate environmental risk as future metal concentrations with a limited range of possibilities, based on a scientific evaluation of uncertainty.

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

International Nuclear Information System (INIS)

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

2009-01-01

The primary target for uranium toxicity is the kidney. The most frequently used guideline for uranium kidney burdens is the International Commission on Radiation Protection (ICRP) value of 3 (micro)g 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

Potential uses of genetic geological modelling to identify new uranium provinces

International Nuclear Information System (INIS)

Finch, W.I.

1982-01-01

Genetic-geological modelling is the placing of the various processes of the development of a uranium province into distinct stages that are ordered chronologically and made part of a matrix with corresponding geologic evidence. The models can be applied to a given region by using one of several methods to determine a numerical favorability rating. Two of the possible methods, geologic decision analysis and an oil-and-gas type of play analysis, are briefly described. Simplified genetic models are given for environments of the quartz-pebble conglomerate, unconformity-related vein, and sandstone types of deposits. Comparison of the genetic models of these three sedimentary-related environments reveals several common attributes that may define a general uranium province environment

Geological 3-D modelling and resources estimation of the Budenovskoye uranium deposit (Kazakhstan)

International Nuclear Information System (INIS)

Boytsov, A.; Heyns, M.; Seredkin, M.

2014-01-01

The Budenovskoye deposit is the biggest sandstone-hosted, roll front type uranium deposit in Kazakhstan and in the world. Uranium mineralization occurs in the unconsolidated lacustrine-alluvial sediments of Late Cretaceous Mynkuduk and Inkuduk horizons. The Budenovskoye deposit was split into four areas for development with the present Karatau ISL Mine operating No. 2 area and Akbastau ISL Mine Nos. 1, 3 and 4 areas. Mines are owned by Kazatomprom and Uranium One in equal shares. CSA Global was retained by Uranium One to update in accordance with NI 43-101 the Mineral Resource estimates for the Karatau and Akbastau Mines. The modelling Reports shows a significant increase in total uranium resources tonnage at both mines when compared to the March 2012 NI 43-101 resource estimate: at Karartau measured and indicated resources increased by 586% while at Akbastau by 286%. It has also added a 55,766 tonnes U to the Karatau Inferred Mineral Resource category.The new estimates result from the application of 3-D modelling techniques to the extensive database of drilling information, new exploration activities.

A Model for High-Strain-Rate Deformation of Uranium-Niobium Alloys

Energy Technology Data Exchange (ETDEWEB)

F.L.Addessio; Q.H.Zuo; T.A.Mason; L.C.Brinson

2003-05-01

A thermodynamic approach is used to develop a framework for modeling uranium-niobium alloys under the conditions of high strain rate. Using this framework, a three-dimensional phenomenological model, which includes nonlinear elasticity (equation of state), phase transformation, crystal reorientation, rate-dependent plasticity, and porosity growth is presented. An implicit numerical technique is used to solve the evolution equations for the material state. Comparisons are made between the model and data for low-strain-rate loading and unloading as well as for heating and cooling experiments. Comparisons of the model and data also are made for low- and high-strain-rate uniaxial stress and uniaxial strain experiments. A uranium-6 weight percent niobium alloy is used in the comparisons of model and experiment.

First-Principles Integrated Adsorption Modeling for Selective Capture of Uranium from Seawater by Polyamidoxime Sorbent Materials.

Science.gov (United States)

Ladshaw, Austin P; Ivanov, Alexander S; Das, Sadananda; Bryantsev, Vyacheslav S; Tsouris, Costas; Yiacoumi, Sotira

2018-04-18

Nuclear power is a relatively carbon-free energy source that has the capacity to be utilized today in an effort to stem the tides of global warming. The growing demand for nuclear energy, however, could put significant strain on our uranium ore resources, and the mining activities utilized to extract that ore can leave behind long-term environmental damage. A potential solution to enhance the supply of uranium fuel is to recover uranium from seawater using amidoximated adsorbent fibers. This technology has been studied for decades but is currently plagued by the material's relatively poor selectivity of uranium over its main competitor vanadium. In this work, we investigate the binding schemes between uranium, vanadium, and the amidoxime functional groups on the adsorbent surface. Using quantum chemical methods, binding strengths are approximated for a set of complexation reactions between uranium and vanadium with amidoxime functionalities. Those approximations are then coupled with a comprehensive aqueous adsorption model developed in this work to simulate the adsorption of uranium and vanadium under laboratory conditions. Experimental adsorption studies with uranium and vanadium over a wide pH range are performed, and the data collected are compared against simulation results to validate the model. It was found that coupling ab initio calculations with process level adsorption modeling provides accurate predictions of the adsorption capacity and selectivity of the sorbent materials. Furthermore, this work demonstrates that this multiscale modeling paradigm could be utilized to aid in the selection of superior ligands or ligand compositions for the selective capture of metal ions. Therefore, this first-principles integrated modeling approach opens the door to the in silico design of next-generation adsorbents with potentially superior efficiency and selectivity for uranium over vanadium in seawater.

Hydrogeochemical modelling of an active system of uranium fixation by organic soils and sediments (Needle's Eye, Scotland)

International Nuclear Information System (INIS)

Jamet, P.; Schmitt, J.M.; Ledoux, E.; Hooker, P.J.; Escalier des Orres, P.

1993-01-01

Uranium accumulation in organic-rich sediments can be closely modelled by assuming that the dominant effect of the uranium-organic matter interaction is the direct or indirect reduction of uranyl compounds to form U(IV) minerals, especially uraninite-pitchblende. Application of this model to the Needle's Eye (Scotland) site where uranium is actively accumulating in Quaternary sediments demonstrates that uranium accumulation is both effective and rapid in environments involving shallow, organic-rich, reducing horizons. The period of uranium deposit formation at Needle's Eye is estimated to be as short as 5000 years. The transport of uranium to the site of deposition by oxidizing groundwaters and the channelling of these oxidizing uraniferous groundwaters are identified as important factors involved in the rapid accumulation of uranium. The regional hydrogeological model indicates that a fault in the area appears to act as a hydraulic screen for the uraniferous groundwaters. On one side of the fault the Quaternary sediments are well drained whilst on the other the flow of groundwater seeps out creating a major flux just at the bottom of the organic-rich layers. The local hydrogeological model shows that the groundwater flow is vertical in this area. A third significant factor in the development of these uranium accumulations is the presence of a significant nearby source of leachable primary uranium. In the case of the Needle's Eye site this is in the form of some thirty 185 ± 20 Ma, pitchblende-bearing veins. 32 refs., 10 figs., 8 tabs

Pharmacokinetic models relevant to toxicity and metabolism for uranium in humans and animals

International Nuclear Information System (INIS)

Wrenn, M.E.

1989-01-01

Models to predict short and long term accumulation of uranium in the human kidney are reviewed and summarised. These are generally first order linear compartmental models or pseudo-pharmacokinetic models such as the retention model of the ICRP. Pharmacokinetic models account not only for transfer from blood to organs, but also recirculation from the organ to blood. The most recent information on mammalian and human metabolism of uranium is used to establish a revised model. The model is applied to the short term accumulation of uranium in the human kidney after a single rapid dosage to the blood, such as that obtained by inhaling UF6 or its hydrolysis products. It is shown that the maximum accumulation in the kidney under these conditions is less than the fraction of the material distributed from the blood to kidney if a true pharmacokinetic model is used. The best coefficients applicable to man in the authors' view are summarised in model V. For a half-time of two days in the mammalian kidney, the maximum concentration in kidney is 75% of that predicted by a retention model such as that used by the ICRP following a single acute intake. We conclude that one must use true pharmacokinetic models, which incorporate recirculation from the organs to the blood, in order to realistically predict time dependent uptake in the kidneys and other organs. Information is presented showing that the half-time for urinary excretion of soluble uranium in man after inhalation of UF6 is about one quarter of a day. (author)

Effects of drop testing on scale model shipping containers shielded with depleted uranium

International Nuclear Information System (INIS)

Butler, T.A.

1980-02-01

Three scale model shipping containers shielded with depleted uranium were dropped onto an essentially unyielding surface from various heights to determine their margins to failure. This report presents the results of a thorough posttest examination of the models to check for basic structural integrity, shielding integrity, and deformations. Because of unexpected behavior exhibited by the depleted uranium shielding, several tests were performed to further characterize its mechanical properties. Based on results of the investigations, recommendations are made for improved container design and for applying the results to full-scale containers. Even though the specimens incorporated specific design features, the results of this study are generally applicable to any container design using depleted uranium

Risk evaluation of uranium mining: A geochemical inverse modelling approach

Science.gov (United States)

Rillard, J.; Zuddas, P.; Scislewski, A.

2011-12-01

It is well known that uranium extraction operations can increase risks linked to radiation exposure. The toxicity of uranium and associated heavy metals is the main environmental concern regarding exploitation and processing of U-ore. In areas where U mining is planned, a careful assessment of toxic and radioactive element concentrations is recommended before the start of mining activities. A background evaluation of harmful elements is important in order to prevent and/or quantify future water contamination resulting from possible migration of toxic metals coming from ore and waste water interaction. Controlled leaching experiments were carried out to investigate processes of ore and waste (leached ore) degradation, using samples from the uranium exploitation site located in Caetité-Bahia, Brazil. In experiments in which the reaction of waste with water was tested, we found that the water had low pH and high levels of sulphates and aluminium. On the other hand, in experiments in which ore was tested, the water had a chemical composition comparable to natural water found in the region of Caetité. On the basis of our experiments, we suggest that waste resulting from sulphuric acid treatment can induce acidification and salinization of surface and ground water. For this reason proper storage of waste is imperative. As a tool to evaluate the risks, a geochemical inverse modelling approach was developed to estimate the water-mineral interaction involving the presence of toxic elements. We used a method earlier described by Scislewski and Zuddas 2010 (Geochim. Cosmochim. Acta 74, 6996-7007) in which the reactive surface area of mineral dissolution can be estimated. We found that the reactive surface area of rock parent minerals is not constant during time but varies according to several orders of magnitude in only two months of interaction. We propose that parent mineral heterogeneity and particularly, neogenic phase formation may explain the observed variation of the

Influence of uranium hydride oxidation on uranium metal behaviour

International Nuclear Information System (INIS)

Patel, N.; Hambley, D.; Clarke, S.A.; Simpson, K.

2013-01-01

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)

Influence of uranium hydride oxidation on uranium metal behaviour

Energy Technology Data Exchange (ETDEWEB)

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

2013-07-01

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)

Double-layer structure model of the uranium generating bed in the land basins of the northwestern China and its significance

International Nuclear Information System (INIS)

Wang Zhilong

1988-04-01

The paper puts forward a double layer structure model of uranium generating bed in the land basins of Northwestern China, i.e. uranium ganerating bed = source layer of uranium+gathering uranium layer. The mechanism of its formation: Feldspar was hydromicatized. Some feldspar, quarts detrital silicate minerals were replaced to redden by the authigenesis of hematite and goethite. In the course of the oxidation, a little uranium is released from the detrital minerals. Because of the oxidation environment, the released uranium wasn't able to be precipitated, only to diffuse to the adjacent grey bed which has low Eh value with uranium-bearing 'stagnant water' fixed in pores during the dewatering process of the diagenesis and form minable uranium deposit. The significance of the model for uranium prospecting are as follows: (1) Uranium source range is much expanded concerning ruanium prospecting in sandstone. (2) For the potential assessment of basin and the selection of potential area, the model is an important prospecting criterion. (3) By using the main criterion uranium-generating bed-arkosic red beds well, the buried ore bodies can be found provided that arkosic red beds were regarded as a significant criterion of uranium-generating bed

A geostatical model for USA uranium deposits

International Nuclear Information System (INIS)

Drew, M.W.

1979-01-01

Evidence exists which suggests that the frequency distributions of both grade and size of metal deposits may be well approximated by lognormal distribution functions. Using data on presently viable deposits and a simplified function which links production cost to deposit grade and size, a bivariate lognormal deposit grade/size distribution may be calibrated for a given geological environment. Exploration is introduced by assuming that the proportion discovered of the potential uranium reserve available at or below a given production can be represented by a fraction of the average deposit size and the limit exploration expenditure. As output, the model derives estimates of total reserves linked to maximum production costs and to exploration expenditure where the latter may be expressed either as expenditure per lb of mineral discovered or as a given percentage of operating profit. Reserve/price functions have been derived for the USA based on USAEC data. Tentative conclusions which may be drawn from the results are: (1) Assuming that a similar proportion of profits continues to be allocated to exploration in the future, then the USA should be able to meet its own national demand for uranium up to the end of the century (say 2 M tons U) at prices up to US$35/lb U 3 O 8 (1.1.75$ values). (2) If instead of all exploration being funded from a fixed maximum proportion of mining company profits, consumers were to fund additional exploration separately, then it is possible that the total unit cost of uranium to the consumers would thereby be reduced. It should be stressed that these conclusions are tentative and are only as reliable as the input data and assumptions of the model. In particular no account is taken of commercial or political forces which could artificially restrict supplies or raise prices. The model should be regarded as a first attempt and is offered as a basis for discussion leading to further development. (author)

Comminution of the U-10Mo by hydriding cycles innovative process

Energy Technology Data Exchange (ETDEWEB)

Faeda, Kelly C.M.; Santos, Ana Maria M. dos; Paula, Joao B. de; Pereira, Edilson M.; Pedrosa, Tercio A.; Lameiras, Fernando S.; Ferraz, Wilmar B., E-mail: ferrazw@cdtn.br, E-mail: kelly.faeda@prof.una.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2013-07-01

The research, test and producing radioisotopes compact reactors were developed with the use of high levels of enriched fuel of approximately 90% of the fissile isotope U-235. Since the 80s', a policy under the context of international program RERTR (Reduced Enrichment for Research and Test Reactors) encourages the fuel replacement of the high enriched fuel by the low one of about 20 % U-235. One way to compensate the substitution for the low enrichment fuel is to employ high density metal uranium alloys. The fabrication of compact reactor fuel uses the metal matrix dispersion and, for this, uranium alloys are used in the form of powders. Despite the high densities, the metallic uranium based alloys are ductile and therefore difficult to be comminuted. Among the different comminution processes, the hydriding-dehydriding process has proved most advantageous, primarily due to their relative simplicity of processing and low manufacturing cost. In this paper, we present the results of the development of the U-10Mo alloy comminution process by the hydriding-dehydriding method on a laboratory scale. Samples of the alloy were subjected to different hydriding cycle numbers in order to verify its influence in relation to the particle size distribution of powders. Powders of different particle sizes were obtained and characterized by the physical and morphological characteristics by optical microscopy, scanning electron microscopy and X ray diffraction. The obtained results are evaluated and discussed. (author)

Modelling of contaminant release from a uranium mine tailings site

International Nuclear Information System (INIS)

Kahnt, Rene; Metschies, Thomas

2007-01-01

Available in abstract form only. Full text of publication follows: Uranium mining and milling continuing from the early 1960's until 1990 close to the town of Seelingstaedt in Eastern Germany resulted in 4 tailings impoundments with a total tailings volume of about 105 Mio. m 3 . Leakage from these tailings impoundments enters the underlying aquifers and is discharged into surface water streams. High concentration of salts, uranium and several heavy metals are released from the tailings. At present the tailings impoundments are reshaped and covered. For the identification of suitable remediation options predictions of the contaminant release for different remediation scenarios have to be made. A compartment model representing the tailings impoundments and the surrounding aquifers for the calculation of contaminant release and transport was set up using the software GOLDSIM. This compartment model describes the time dependent hydraulic conditions within the tailings and the surrounding aquifers taking into account hydraulic and geotechnical processes influencing the hydraulic properties of the tailings material. A simple geochemical approach taking into account sorption processes as well as retardation by applying a k d -approach was implemented to describe the contaminant release and transport within the hydraulic system. For uranium as the relevant contaminant the simple approach takes into account additional geochemical conditions influencing the mobility. Alternatively the model approach allows to include the results of detailed geochemical modelling of the individual tailings zones which is than used as source term for the modelling of the contaminant transport in the aquifer and to the receiving streams. (authors)

Modelling of uranium inputs and its fate in soil; Modellierung von Uraneintraegen aus Duengern und ihr Verbleib im Boden

Energy Technology Data Exchange (ETDEWEB)

Achatz, M. [Bundesamt fuer Strahlenschutz, Berlin (Germany); Urso, L. [Bundesamt fuer Strahlenschutz, Oberschleissheim (Germany)

2016-07-01

87 % of mineral phosphate fertilizers are produced of sedimentary rock phosphate, which generally contains heavy metals, like uranium. The solution and migration behavior of uranium is apart from its redox ratio, determined by its pH conditions as well as its ligand quality and quantity. A further important role in sorption is played by soil components like clay minerals, pedogenic oxides and soil organic matter. To provide a preferably detailed speciation model of U in soil several physical and chemical components have to be included to be able to state distribution coefficients (k{sub D}) and sorption processes. The model of Hormann and Fischer served as the basis of modelling uranium mobility in soil by using the program PhreeqC. The usage of real soil and soil water measurements may contribute to identify factors and processes influencing the mobility of uranium under preferably realistic conditions. Additionally, the assessment of further predictions towards uranium migration in soil can be made based on a modelling with PhreeqC. The modelling of uranium inputs and its fate in soil can help to elucidate the human caused occurrence or geogenic origin of uranium in soil.

Sorption of uranium (VI) on homoionic sodium smectite experimental study and surface complexation modeling.

Science.gov (United States)

Korichi, Smain; Bensmaili, Aicha

2009-09-30

This paper is an extension of a previous paper where the natural and purified clay in the homoionic Na form were physico-chemically characterized (doi:10.1016/j.clay.2008.04.014). In this study, the adsorption behavior of U (VI) on a purified Na-smectite suspension is studied using batch adsorption experiments and surface complexation modeling (double layer model). The sorption of uranium was investigated as a function of pH, uranium concentration, solid to liquid ratio, effect of natural organic matter (NOM) and NaNO(3) background electrolyte concentration. Using the MINTEQA2 program, the speciation of uranium was calculated as a function of pH and uranium concentration. Model predicted U (VI) aqueous speciation suggests that important aqueous species in the [U (VI)]=1mg/L and pH range 3-7 including UO(2)(2+), UO(2)OH(+), and (UO(2))(3)(OH)(5)(+). The concentration of UO(2)(2+) decreased and that of (UO(2))(3)(OH)(5)(+) increased with increasing pH. The potentiometric titration values and uptake of uranium in the sodium smectite suspension were simulated by FITEQL 4.0 program using a two sites model, which is composed of silicate and aluminum reaction sites. We compare the acidity constants values obtained by potentiometric titration from the purified sodium smectite with those obtained from single oxides (quartz and alpha-alumina), taking into account the surface heterogeneity and the complex nature of natural colloids. We investigate the uranium sorption onto purified Na-smectite assuming low, intermediate and high edge site surfaces which are estimated from specific surface area percentage. The sorption data is interpreted and modeled as a function of edge site surfaces. A relationship between uranium sorption and total site concentration was confirmed and explained through variation in estimated edge site surface value. The modeling study shows that, the convergence during DLM modeling is related to the best estimation of the edge site surface from the N(2

Streamline-concentration balance model for in-situ uranium leaching and site restoration

International Nuclear Information System (INIS)

Bommer, P.M.; Schechter, R.S.; Humenick, M.J.

1981-03-01

This work presents two computer models. One describes in-situ uranium leaching and the other describes post leaching site restoration. Both models use a streamline generator to set up the flow field over the reservoir. The leaching model then uses the flow data in a concentration balance along each streamline coupled with the appropriate reaction kinetics to calculate uranium production. The restoration model uses the same procedure except that binary cation exchange is used as the restoring mechanism along each streamline and leaching cation clean up is simulated. The mathematical basis for each model is shown in detail along with the computational schemes used. Finally, the two models have been used with several data sets to point out their capabilities and to illustrate important leaching and restoration parameters and schemes

Streamline-concentration balance model for in situ uranium leaching and site restoration

International Nuclear Information System (INIS)

Bommer, P.M.

1979-01-01

This work presents two computer models. One describes in situ uranium leaching and the other describes post leaching site restoration. Both models use a streamline generator to set up the flow field over the reservoir. The leaching model then uses the flow data in a concentration balance along each streamline coupled with the appropriate reaction kinetics to calculate uranium production. The restoration model uses the same procedure ecept that binary cation exchange is used as the restoring mechanism along each streamline and leaching cation clean up is stimulated. The mathematical basis for each model is shown in detail along with the computational schemes used. Finally, the two models have been used with several data sets to point out their capabilities and to illustrate important leaching and restoration parameters and schemes

The use of geochemical speciation modelling to predict the impact of uranium to freshwater biota

International Nuclear Information System (INIS)

Markich, S.J.; Brown, P.L.; Jeffree, R.A.

1996-01-01

Uranium is the prime potential contaminant in mine waste waters that may be released from the Ranger Uranium Mine (RUM) into the receiving waters of the Magela Creek, Alligator Rivers Region, Northern Australia. The potential ecological impact of the migration of uranium, that would result from an elevation in its concentration above background, in the Magela Creek downstream of the RUM, has been experimentally investigated by integrating biomonitoring with geochemical speciation modelling. The freshwater bivalve Velesunio angasi, abundant throughout the Magela Creek catchment, was exposed to a variety of uranium concentrations in a synthetic Magela Creek water, at four pH levels (5.0, 5.3, 5.5 and 6.0), in the presence (3.05 and 7.50 mg l -1 ) and absence of a model fulvic acid (FA), and its behavioural response was measured. Speciation modelling, using the HARPHRQ code, provided evidence that UO 2+ 2 and UO 2 OH + are the uranium species most responsible (ca. 96%) for eliciting an adverse behavioural response when UO 2+ 2 is assigned twice the toxic effect of UO 2 OH + . This finding rejects the notion that biota respond specifically to the sum total of inorganic uranyl species. (orig.)

Mantle geofluid and uranium ore-formation model

International Nuclear Information System (INIS)

Wu Jianhua; Liu Shuai; Yu Dagan; Zhang Bangtong

2005-01-01

Results of the recent research show that volcanic-type and granite-type uranium deposits have both early and late phases of uranium mineralization, and the early phase uranium mineralization is characterized by metallogenetic features of mantle fluids. This paper discusses the geofluids and related metallogenesis, as well as characteristics of early phase uranium mineralisation, and emphasizes, that the ΣCO 2 , U and H 2 O, that comprise the bulk of the ore-forming hot fluids, are originated from different sources, namely CO 2 comes from mantle fluids, U comes from country rocks the mantle fluids have passed during their ascending way, and H 2 O comes from mantle fluids and country rocks the mantle fluids have passed during their ascending way. (authors)

Uranium metallogenic model related to CO2 and hydrocarbon in granite type uranium deposits

International Nuclear Information System (INIS)

Ou Guangxi; Chen Anfu; Cui Jianyong; Xu Yinhuan; Wang Chunhua; Xu Yan

2001-01-01

The report is concerned with the inseparable connections between the uranium migration, enrichment rule and the geochemical characteristics of CO 2 and hydrocarbon gas, as well as the relations between the deposit locations and the gas abnormal distribution in rocky body, which are based on the analysis of some data and phenomena in 11 typical deposits in 2 granite type uranium ore fields, including the observations of 250 rocky fluid inclusion sections and the analyzed data of which 2470 are in gas composition, 200 in uranium content, 50 in thermometry. All the conclusions are drawn from different angles for the first time and this new exploration and advancement fills up the blank of gas geochemistry study in uranium deposits or other metal deposits

Radiological modeling software for underground uranium mines

International Nuclear Information System (INIS)

Bjorndal, B.; Moridi, R.

1999-01-01

The Canadian Institute for Radiation Safety (CAIRS) has developed computer simulation software for modeling radiological parameters in underground uranium mines. The computer program, called 3d RAD, allows radiation protection professionals and mine ventilation engineers to quickly simulate radon and radon progeny activity concentrations and potential alpha energy concentrations in complex mine networks. The simulation component of 3d RAD, called RSOLVER, is an adaptation of an existing modeling program called VENTRAD, originally developed at Queen's University, Ontario. Based on user defined radiation source terms and network physical properties, radiological parameters in the network are calculated iteratively by solving Bateman's Equations in differential form. The 3d RAD user interface was designed in cooperation with the Canada Centre for Mineral and Energy Technology (CANMET) to improve program functionality and to make 3d RAD compatible with the CANMET ventilation simulation program, 3d CANVENT. The 3d RAD program was tested using physical data collected in Canadian uranium mines. 3d RAD predictions were found to agree well with theoretical calculations and simulation results obtained from other modeling programs such as VENTRAD. Agreement with measured radon and radon progeny levels was also observed. However, the level of agreement was found to depend heavily on the precision of source term data, and on the measurement protocol used to collect radon and radon progeny levels for comparison with the simulation results. The design and development of 3d RAD was carried out under contract with the Saskatchewan government

The migration of uranium through sandstone

International Nuclear Information System (INIS)

Bennett, D.G.; Read, D.; Lawless, T.A.; Sims, R.J.

1992-01-01

Three column experiments are described in which the migration of uranium through Clashach Sandstone was studied. A priori predictions of uranium migration in the experiments were made using an equilibrium chemical transport model. The experimental results showed that, even under oxidising conditions, the migration of uranium is strongly retarded owing to the affinity of uranium for mineral surfaces. For the relatively simple chemical system investigated, the chemical transport model was successful in predicting the migration of uranium and its distribution along the column. (author)

Advantages of integration of uranium exploration data in GIS and models as tools for decision support

International Nuclear Information System (INIS)

Tusveld, M.C.L.

1997-01-01

In many areas where uranium has been or is explored, an enormous amount of data on geology and hydrogeology is available. When these uranium exploration data are stored in a structured way, they can be made useful for other purposes dm uranium exploration only. For instance, in case of environmental pollution, which is often a side-effect of uranium activities such as mining and leaching, the data can be used to develop a computer model of the environment. With such a model impacts can be calculated of different scenarios for cleaning up or isolation of the pollution. A GIS can be used to store the data, to visualize the data (map production) and to analyse the data, but also to calculate input for the models. The advantages of using GIS and models as tools for decision support are explained with the Contaminant Transport Information System (CTIS) as a case study. The CTIS has been developed for remediation operations in the uranium mining area Straz pod Ralskem and Hamr in the Czech Republic. The CTIS consists of a GIS database, a regional groundwater flow model and a local contaminant transport model as well as interfaces for data transfer between the components of the information system. The power of the CTIS lies in the fact that the modelling necessary for the design of a remediation operation can be carried out efficiently by using one of the two models, depending on the specific question. Thus alternative remediation scenarios can be judged easily and fairly on their consequences and effectiveness. (author)

The computerized semi-quantitative comprehensive identification-evaluation model for the large-sized in-situ leachable sandstone type uranium deposits in Northern Xinjiang, China

Energy Technology Data Exchange (ETDEWEB)

Zhengbang, Wang; Mingkuan, Qin; Ruiquan, Zhao; Shenghuang, Tang [Beijing Research Inst. of Uranium Geology, CNNC (China); Baoqun, Wang; Shuangxing, Lin [Geo-prospecting Team No. 216, CNNC (China)

2001-08-01

The process of establishment of the model includes following steps: (1) Systematically studying a known typical in-situ leachable sandstone type uranium deposit--Deposit No. 512 in Yili basin, analyzing its controlling factors and establishing its metallogenetic model; (2) Establishing the metallogenetic models of this type of uranium deposit and uranium-bearing area on the basis of comparison study on the deposit No. 512 with the same type uranium deposits in the world; (3) Creating the computerized semi-quantitative comprehensive identification-evaluation model for the large-sized in-situ leachable sandstone type uranium deposits in northern Xinjiang; (4) Determining the standards of giving a evaluation-mark for each controlling factor of in-situ leachable sandstone type uranium deposit and uranium-bearing area; (5) Evaluating uranium potential and prospect of the unknown objective target.

The computerized semi-quantitative comprehensive identification-evaluation model for the large-sized in-situ leachable sandstone type uranium deposits in Northern Xinjiang, China

International Nuclear Information System (INIS)

Wang Zhengbang; Qin Mingkuan; Zhao Ruiquan; Tang Shenghuang; Wang Baoqun; Lin Shuangxing

2001-01-01

The process of establishment of the model includes following steps: (1) Systematically studying a known typical in-situ leachable sandstone type uranium deposit--Deposit No. 512 in Yili basin, analyzing its controlling factors and establishing its metallogenetic model; (2) Establishing the metallogenetic models of this type of uranium deposit and uranium-bearing area on the basis of comparison study on the deposit No. 512 with the same type uranium deposits in the world; (3) Creating the computerized semi-quantitative comprehensive identification-evaluation model for the large-sized in-situ leachable sandstone type uranium deposits in northern Xinjiang; (4) Determining the standards of giving a evaluation-mark for each controlling factor of in-situ leachable sandstone type uranium deposit and uranium-bearing area; (5) Evaluating uranium potential and prospect of the unknown objective target

Modelling of uranium/plutonium splitting in purex process

International Nuclear Information System (INIS)

Boullis, B.; Baron, P.

1987-06-01

A mathematical model simulating the highly complex uranium/plutonium splitting operation in PUREX process has been achieved by the french ''Commissariat a l'Energie Atomique''. The development of such a model, which includes transfer and redox reactions kinetics for all the species involved, required an important experimental work in the field of basis chemical data acquisition. The model has been successfully validated by comparison of its results with those of specific trials achieved (at laboratory scale), and with the available results of the french reprocessing units operation. It has then been used for the design of french new plants splitting operations

The modelling of the uranium-leaching and ion-exchange processes of the Hartebeestfontein Gold Mine and its role in economic plant operation

International Nuclear Information System (INIS)

Broekman, B.R.; Ward, B.

1985-01-01

Computer facilities available in the Metallurgical Department at Hartebeestfontein Gold Mine have enabled the research staff to develope complex, practical mathematical models of their uranium hydrometallurgical processes. Empirical models of uranium leaching, uranium loading on resin and redox potential in leach liquors are discussed. These models, developed with non-linear regression techniques, form the basis of an over all mathematical model for a uranium plant. The most economic operating conditions can be predicted for specific prices of uranium and reagents. Substantial profit improvements have been achieved as a result of the changes in the process and equipment that have been made

Geophysical and geochemical regional evaluation and geophysical model for uranium exploration in the western part of Yanliao region

International Nuclear Information System (INIS)

Liu Tengyao; Cui Huanmin; Chen Guoliang; Zhai Yugui

1992-01-01

The western part of Yanliao region is an important uranium metallogenic region. This paper summarizes the regional geophysical model for uranium exploration composed of prediction model for favourable area of mineralization and evaluation model for anomalies on the basis of aeromagnetic and aeroradiometric data interpretation and analysis of the data from carborane and ground gamma spectrometric survey, high accurate magnetic survey, VLF survey and α-collected film survey in mult-displiary research work. The prospective prediction for uranium metallogenesis in this region was also conducted

Corrosion of Uranium in Desert Soil, with Application to GCD Source Term Models

International Nuclear Information System (INIS)

ANDERSON, HOWARD L.; BACA, JULIANNE; KRUMHANSL, JAMES L.; STOCKMAN, HARLAN W.; THOMPSON, MOLLIE E.

1999-01-01

Uranium fragments from the Sandia Sled Track were studied as analogues for weapons components and depleted uranium buried at the Greater Confinement Disposal (GCD) site in Nevada. The Sled Track uranium fragments originated as weapons mockups and counterweights impacted on concrete and soil barriers, and experienced heating and fragmentation similar to processes thought to affect the Nuclear Weapons Accident Residues (NWAR) at GCD. Furthermore, the Sandia uranium was buried in unsaturated desert soils for 10 to 40 years, and has undergone weathering processes expected to affect the GCD wastes. Scanning electron microscopy, X-ray diffraction and microprobe analyses of the fragments show rapid alteration from metals to dominantly VI-valent oxy-hydroxides. Leaching studies of the samples give results consistent with published U-oxide dissolution rates, and suggest longer experimental periods (ca. 1 year) would be required to reach equilibrium solution concentrations. Thermochemical modeling with the EQ3/6 code indicates that the uranium concentrations in solutions saturated with becquerelite could increase as the pore waters evaporate, due to changes in carbonate equilibria and increased ionic strength

Uranium enrichment

International Nuclear Information System (INIS)

1989-01-01

GAO was asked to address several questions concerning a number of proposed uranium enrichment bills introduced during the 100th Congress. The bill would have restructured the Department of Energy's uranium enrichment program as a government corporation to allow it to compete more effectively in the domestic and international markets. Some of GAO's findings discussed are: uranium market experts believe and existing market models show that the proposed DOE purchase of a $750 million of uranium from domestic producers may not significantly increase production because of large producer-held inventories; excess uranium enrichment production capacity exists throughout the world; therefore, foreign producers are expected to compete heavily in the United States throughout the 1990s as utilities' contracts with DOE expire; and according to a 1988 agreement between DOE's Offices of Nuclear Energy and Defense Programs, enrichment decommissioning costs, estimated to total $3.6 billion for planning purposes, will be shared by the commercial enrichment program and the government

Concentrations of uranium and thorium isotopes in uranium millers' and miners' tissues

International Nuclear Information System (INIS)

Wrenn, M.E.; Singh, N.P.; Paschoa, A.S.; Lloyd, R.D.; Saccomanno, G.

1985-09-01

The alpha-emitting isotopes of uranium and thorium were determined in the lungs of 14 former uranium miners and in soft tissues and bones of three miners and two millers. These radionuclides were also determined in soft tissues and bones of seven normal controls. The average concentrations in pCi/kg wet weight in 17 former miners' lungs are as follows: 238 U, 75; 234 U, 80; 230 Th, 79. Concentrations of each nuclide ranged from 2 to 325 pCi/kg. The average ratio of 238 U/ 234 U was 0.92, ranging from 0.64 to 1.06. The mean ratio of 230 Th/ 234 U was 1.04, ranging from 0.33 to 3.54. The near equilibrium between 230 Th and /sup 238,234/U indicates that the rate of elimination of uranium and thorium from lungs is the same in former uranium miners. The concentrations of 234 U and 238 U were highest in lung; however, the concentration of 230 Th in bones was either higher than or comparable to its concentration in lung. The concentration ratios of 230 Th/ 234 U in bone of uranium miners and millers measured in our laboratory have been compared with results predicted by ICRP-30 metabolic models. These results indicate that the ICRP metabolic models for thorium and uranium were only marginally successful in predicting the ratio of 230 Th/ 234 U in bones, and that effective release rate of uranium from skeleton may be more rapid than predicted by the ICRP model. 9 figs., 21 tabs

World uranium resources

International Nuclear Information System (INIS)

Deffeyes, K.S.; MacGregor, I.D.

1980-01-01

To estimate the total resource availability of uranium, the authors' approach has been to ask whether the distribution of uranium in the earth's crust can be reasonably approximated by a bell-shaped log-normal curve. In addition they have asked whether the uranium deposits actually mined appear to be a portion of the high-grade tail, or ascending slope, of the distribution. This approach preserves what they feel are the two most important guiding principles of Hubbert's work, for petroleum, namely recognizing the geological framework that contains the deposits of interest and examining the industry's historical record of discovering those deposits. Their findings, published recently in the form of a book-length report prepared for the US Department of Energy, suggest that for uranium the crustal-distribution model and the mining-history model can be brought together in a consistent picture. In brief, they conclude that both sets of data can be described by a single log-normal curve, the smoothly ascending slope of which indicates approximately a 300-fold increase in the amount of uranium recoverable for each tenfold decrease in ore grade. This conclusion has important implications for the future availability of uranium. They hasten to add, however, that this is only an approximative argument; no rigorous statistical basis exists for expecting a log-normal distribution. They continue, pointing out the enormously complex range of geochemical behavior of uranium - and its wide variety of different binds of economic deposit. Their case study, supported by US mining records, indicates that the supply of uranium will not be a limiting factor in the development of nuclear power

Pre implanted mouse embryos as model for uranium toxicology studies

International Nuclear Information System (INIS)

Kundt, Miriam S.

2001-01-01

Full text: The search of 'in vitro' toxicology model that can predict toxicology effects 'in vivo' is a permanent challenge. A toxicology experimental model must to fill to certain requirements: to have a predictive character, an appropriate control to facilitate the interpretation of the data among the experimental groups, and to be able to control the independent variables that can interfere or modify the results that we are analyzing. The preimplantation embryos posses many advantages in this respect: they are a simple model that begins with the development of only one cell. The 'in vitro' model reproduces successfully the 'in vivo' situation. Due to the similarity that exists among the embryos of mammals during this period the model is practically valid for other species. The embryo is itself a stem cell, the toxicology effects are early observed in his clonal development and the physical-chemical parameters are easily controllable. The purpose of the exhibition is to explain the properties of the pre implanted embryo model for toxicology studies of uranium and to show our experimental results. The cultivation 'in vitro' of mouse embryos with uranylo nitrate demonstrated that the uranium causes from the 13 μgU/ml delay of development, decrease the number of cells per embryo and hipoploidy in the embryonic blastomere. (author)

Development and application of model RAIA uranium on-line analyser

International Nuclear Information System (INIS)

Dong Yanwu; Song Yufen; Zhu Yaokun; Cong Peiyuan; Cui Songru

1999-01-01

The working principle, structure, adjustment and application of model RAIA on-line analyser are reported. The performance of this instrument is reliable. For identical sample, the signal fluctuation in continuous monitoring for four months is less than +-1%. According to required measurement range, appropriate length of sample cell is chosen. The precision of measurement process is better than 1% at 100 g/L U. The detection limit is 50 mg/L. The uranium concentration in process stream can be displayed automatically and printed at any time. It presents 4∼20 mA current signal being proportional to the uranium concentration. This makes a long step towards process continuous control and computer management

Metallogenesis and metallogenic model of Nuheting uranium deposit in Erlian Basin

International Nuclear Information System (INIS)

Li Hongjun; Kuang Wenzhan

2010-01-01

Based on the study on geological characteristics, metallogesis and geochemical features in Nuheting uranium deposit, it is considered that the deposit belongs to syn-sedimentary and epigenetic reworking type. The deposit position was controlled by the lake area developed during Erlian period in Late Cretaceous. The metallognesis has experienced three stages, they are syn-sedimentary metallogenesis, epigenetic reworking metallogenesis and exogenic metallogenesis. The ore-forming ages are respectively 85 Ma, (41±5)Ma and 6-13 Ma. Based on the summary of metallogenic geological features,metallogenesis and geochemical features, the metallogenic model of Nuheting uranium deposit has been established. (authors)

Root uptake of uranium by a higher plant model (Phaseolus vulgaris) bioavailability from soil solution

International Nuclear Information System (INIS)

Laroche, L.; Henner, P.; Camilleri, V.; Garnier-Laplace, J.

2004-01-01

Uranium behaviour in soils is controlled by actions and interactions between physicochemical and biological processes that also determine its bioavailability. In soil solution, uranium(+VI) aqueous speciation undergoes tremendous changes mainly depending on pH, carbonates, phosphates and organic matter. In a first approach to identify bioavailable species of U to plants, cultures were performed using hydroponics, to allow an easy control of the composition of the exposure media. The latter, here an artificial soil solution, was designed to control the uranium species in solution. The geochemical speciation code JCHESS using a database compiled from the OECD/NEA thermochemical database project and verified was used to perform the solution speciation calculations. On this theoretical basis, three domains were defined for short-duration well-defined laboratory experiments in simplified conditions: pH 4.9, 5.8 and 7 where predicted dominant species are uranyl ions, hydroxyl complexes and carbonates respectively. For these domains, biokinetics and characterization of transmembrane transport according to a classical Michaelis Menten approach were investigated. The Free Ion Model (or its derived Biotic Ligand Model) was tested to determine if U uptake is governed by the free uranyl species or if other metal complexes can be assimilated. The effect of different variables on root assimilation efficiency and phyto-toxicity was explored: presence of ligands such as phosphates or carbonates and competitive ions such as Ca 2+ at the 3 pH. According to previous experiments, uranium was principally located in roots whatever the pH and no difference in uranium uptake was evidenced between the main growth stages of the plant. Within the 3 studied chemical domains, results from short-term kinetics evidenced a linear correlation between total uranium concentration in bean roots and that in exposure media, suggesting that total uranium in soil solution could be a good predictor for

Root uptake of uranium by a higher plant model (Phaseolus vulgaris) bioavailability from soil solution

Energy Technology Data Exchange (ETDEWEB)

Laroche, L.; Henner, P.; Camilleri, V.; Garnier-Laplace, J. [CEA Cadarache (DEI/SECRE/LRE), Laboratory of Radioecology and Ecotoxicology, Institute for Radioprotection and Nuclear Safety, 13 - Saint-Paul-lez-Durance (France)

2004-07-01

Uranium behaviour in soils is controlled by actions and interactions between physicochemical and biological processes that also determine its bioavailability. In soil solution, uranium(+VI) aqueous speciation undergoes tremendous changes mainly depending on pH, carbonates, phosphates and organic matter. In a first approach to identify bioavailable species of U to plants, cultures were performed using hydroponics, to allow an easy control of the composition of the exposure media. The latter, here an artificial soil solution, was designed to control the uranium species in solution. The geochemical speciation code JCHESS using a database compiled from the OECD/NEA thermochemical database project and verified was used to perform the solution speciation calculations. On this theoretical basis, three domains were defined for short-duration well-defined laboratory experiments in simplified conditions: pH 4.9, 5.8 and 7 where predicted dominant species are uranyl ions, hydroxyl complexes and carbonates respectively. For these domains, biokinetics and characterization of transmembrane transport according to a classical Michaelis Menten approach were investigated. The Free Ion Model (or its derived Biotic Ligand Model) was tested to determine if U uptake is governed by the free uranyl species or if other metal complexes can be assimilated. The effect of different variables on root assimilation efficiency and phyto-toxicity was explored: presence of ligands such as phosphates or carbonates and competitive ions such as Ca{sup 2+} at the 3 pH. According to previous experiments, uranium was principally located in roots whatever the pH and no difference in uranium uptake was evidenced between the main growth stages of the plant. Within the 3 studied chemical domains, results from short-term kinetics evidenced a linear correlation between total uranium concentration in bean roots and that in exposure media, suggesting that total uranium in soil solution could be a good predictor

Multi-coupling dynamic model and 3d simulation program for in-situ leaching of uranium mining

International Nuclear Information System (INIS)

Tan Kaixuan; Zeng Sheng; Sang Xiao; Sun Bing

2010-01-01

The in-situ leaching of uranium mining is a very complicated non-linear dynamic system, which involves couplings and positive/negative feedback among many factors and processes. A comprehensive, coupled multi-factors and processes dynamic model and simulation method was established to study the in-situ leaching of uranium mining. The model accounts for most coupling among various processes as following: (1) rock texture mechanics and its evolution, (2)the incremental stress rheology of rock deformation, (3) 3-D viscoelastic/ plastic multi-deformation processes, (4) hydrofracturing, (5) tensorial (anisotropic) fracture and rock permeability, (6) water-rock interactions and mass-transport (both advective and diffusive), (7) dissolution-induced chemical compaction, (8) multi-phase fluid flow. A 3-D simulation program was compiled based on Fortran and C++. An example illustrating the application of this model to simulating acidification, production and terminal stage of in situ leaching of uranium mining is presented for the some mine in Xinjiang, China. This model and program can be used for theoretical study, mine design, production management, the study of contaminant transport and restoration in groundwater of in-situ leaching of uranium mining. (authors)

Sensitivity Analysis and Parameter Estimation for a Reactive Transport Model of Uranium Bioremediation

Science.gov (United States)

Meyer, P. D.; Yabusaki, S.; Curtis, G. P.; Ye, M.; Fang, Y.

2011-12-01

A three-dimensional, variably-saturated flow and multicomponent biogeochemical reactive transport model of uranium bioremediation was used to generate synthetic data . The 3-D model was based on a field experiment at the U.S. Dept. of Energy Rifle Integrated Field Research Challenge site that used acetate biostimulation of indigenous metal reducing bacteria to catalyze the conversion of aqueous uranium in the +6 oxidation state to immobile solid-associated uranium in the +4 oxidation state. A key assumption in past modeling studies at this site was that a comprehensive reaction network could be developed largely through one-dimensional modeling. Sensitivity analyses and parameter estimation were completed for a 1-D reactive transport model abstracted from the 3-D model to test this assumption, to identify parameters with the greatest potential to contribute to model predictive uncertainty, and to evaluate model structure and data limitations. Results showed that sensitivities of key biogeochemical concentrations varied in space and time, that model nonlinearities and/or parameter interactions have a significant impact on calculated sensitivities, and that the complexity of the model's representation of processes affecting Fe(II) in the system may make it difficult to correctly attribute observed Fe(II) behavior to modeled processes. Non-uniformity of the 3-D simulated groundwater flux and averaging of the 3-D synthetic data for use as calibration targets in the 1-D modeling resulted in systematic errors in the 1-D model parameter estimates and outputs. This occurred despite using the same reaction network for 1-D modeling as used in the data-generating 3-D model. Predictive uncertainty of the 1-D model appeared to be significantly underestimated by linear parameter uncertainty estimates.

Analysis on paleo-hydrogeological conditions of uranium formation in Sawafuqi uranium deposit

International Nuclear Information System (INIS)

Lin Xiaobin; Hao Weilin; Wang Zhiming

2013-01-01

Sawafuqi uranium deposit is located in Kuergan intermontane basin of the South Tianshan (STS) fold belt. On the basis of regional tectonics, paleogeography, paleoclimate and related data, the evolution of intermontane basin could be divided into three hydrogeological cycles. The relationship of uranium mineralization to each cycle was analyzed from the perspective of the evolution of palaeo-hydrogeological conditions, and the uranium metallogenic model in palaeohydrogeology under strongly constructive background was established. (authors)

Models for the adsorption of uranium on titanium dioxide

International Nuclear Information System (INIS)

Jaffrezic-Renault, N.; Poirier-Andrade, H.; Trang, D.H.

1980-01-01

A hydrated titanium oxide whose acid-base properties are well defined has been used to study the retention mechanism of uranium as UO 2 2+ (in acidic media) and as UO 2 (CO 3 ) 3 4- (in carbonate media). The influence of various parameters on the distribution coefficient of uranium (pH, [CO 3 2- ]) and of the adsorption of uranium on the electrophoretic mobilities of the titanium oxide have been investigated. It is shown that, in both media, coordinative TiO-UO 2 bonds are formed. These strong bonds explain the high affinity of the titanium oxide for uranium. (orig.)

Revised uranium--plutonium cycle PWR and BWR models for the ORIGEN computer code

International Nuclear Information System (INIS)

Croff, A.G.; Bjerke, M.A.; Morrison, G.W.; Petrie, L.M.

1978-09-01

Reactor physics calculations and literature searches have been conducted, leading to the creation of revised enriched-uranium and enriched-uranium/mixed-oxide-fueled PWR and BWR reactor models for the ORIGEN computer code. These ORIGEN reactor models are based on cross sections that have been taken directly from the reactor physics codes and eliminate the need to make adjustments in uncorrected cross sections in order to obtain correct depletion results. Revised values of the ORIGEN flux parameters THERM, RES, and FAST were calculated along with new parameters related to the activation of fuel-assembly structural materials not located in the active fuel zone. Recommended fuel and structural material masses and compositions are presented. A summary of the new ORIGEN reactor models is given

Modeling study of gaseous Rn-222, Xe-133, and He-4 for uranium exploration

Energy Technology Data Exchange (ETDEWEB)

Jeter, H.W.

1980-01-01

This work presents one-dimensional mathematical models to simulate the transport of gaseous radon-222 (Rn-222), xenon-133 (Xe-133), and helium-4 (He-4) away from uranium ore deposits. The resulting concentrations of indicator nuclides in the overburden are used to infer the detectability of ore deposits by emanation methods. In the case of homogeneous, non-radioactive formations, Rn-222 and some of its daughter products are calculated to be detectable at distances of several tens of meters from a planar uranium ore deposit (1 m tickness, 0.6% U/sub 3/O/sub 8/, 20% emanation). Models of He-4 diffuson in rock yield highly uncertain results because measurements of diffusion coefficients in actual rock types are lacking and because the flux of helium from deep within the earth is generally unknown. Comparisons of model results to field data suggest that He-4 diffusion coefficients of 10/sup -4/ to 10/sup -5/ cm/sup 2//sec are appropriate. It is speculated that moisture in the rock column could reduce the coefficient significantly compared to the dry-soil case. Inhomogeneity in rock formations is simulated by a multiple-layer model. A comparison of fluorometric uranium data to gamma spectra measurements suggests the migration and deposition of Ra-226 near the water table. Modeling results are improved when this process is taken into account. A constant soil gas velocity of 1 x 10/sup -4/ cm/sec causes indicator concentrations to change by several orders of magnitude. If steady upward soil gas motion exists in nature, the detectability of uranium ore by emanation methods will be significantly different from that indicated by pure diffusion models. Barometric influences on gas transport are simulated by time-dependent numerical models.

Uranium production in thorium/denatured uranium fueled PWRs

International Nuclear Information System (INIS)

Arthur, W.B.

1977-01-01

Uranium-232 buildup in a thorium/denatured uranium fueled pressurized water reactor, PWR(Th), was studied using a modified version of the spectrum-dependent zero dimensional depletion code, LEOPARD. The generic Combustion Engineering System 80 reactor design was selected as the reactor model for the calculations. Reactors fueled with either enriched natural uranium and self-generated recycled uranium or uranium from a thorium breeder and self-generated recycled uranium were considered. For enriched natural uranium, concentrations of 232 U varied from about 135 ppM ( 232 U/U weight basis) in the zeroth generation to about 260 ppM ( 232 U/U weight basis) at the end of the fifth generation. For the case in which thorium breeder fuel (with its relatively high 232 U concentration) was used as reactor makeup fuel, concentrations of 232 U varied from 441 ppM ( 232 U/U weight basis) at discharge from the first generation to about 512 ppM ( 232 U/U weight basis) at the end of the fifth generation. Concentrations in freshly fabricated fuel for this later case were 20 to 35% higher than the discharge concentration. These concentrations are low when compared to those of other thorium fueled reactor types (HTGR and MSBR) because of the relatively high 238 U concentration added to the fuel as a denaturant. Excellent agreement was found between calculated and existing experimental values. Nevertheless, caution is urged in the use of these values because experimental results are very limited, and the relevant nuclear data, especially for 231 Pa and 232 U, are not of high quality

Organ burdens and excretion rates of inhaled uranium - computations using ICRP model

International Nuclear Information System (INIS)

Abani, M.C.; Murthy, K.B.S.; Sunta, C.M.

1988-01-01

Uranium being a highly toxic material, proper estimation of the body burden is very important. During manufacture of uranium fuel, it is likely to enter the body by inhalation. By the body burden and excretion measurements, one should be able to assess whether the intake is within the safe limits or not. This is possible if one performs theoretical calculations and estimates the amount of uranium which builds up in the body as a function of time. Similarly theoretical estimates in case of excretion have to be made. For this purpose, a computer programme has been developed to find out organ burdens and excretion rates resulting from exposure to a radioactive nuclide. ICRP-30 lung model has been used and cases of single instantaneous inhalation of 1 ALI as well as inhalation at a steady rate of ALI/365 per day have been considered. Using this programme, results for uranium aerosols of classes D, W and Y and sizes 0.2, 1 and 5 microns are generated by ND computers in tabular as well as graphical forms. These will be useful in conjunction with body burden measurements by direct counting or excretion analysis. (author). 7 tabs., 56 figs

The Alligator rivers natural analogue - Modelling of uranium and thorium migration in the weathered zone at Koongarra

International Nuclear Information System (INIS)

Skagius, K.; Lindgren, M.; Boghammar, A.; Brandberg, F.; Pers, K.; Widen, H.

1993-08-01

The Koongarra Uranium Deposit in the Alligator Rivers Region in the Northern Territory of Australia is a natural analogue being investigated with the aim to contribute to the understanding of the scientific basis for the long term prediction of radionuclide migration within geological environments relevant to radioactive waste repositories. The dispersion of uranium and decay products in the weathered zone has been modelled with a simple advection-dispersion-reversible sorption model and with a model extended to also consider α-recoil and transfer of radionuclides between different mineral phases of the rock. The modelling work was carried out in several iterations, each including a review of available laboratory and field data, selection of the system to be modelled and suitable model, and a comparison of modelling results with field observations. Uranium concentrations in bulk rock calculated with the simple advection-dispersion- reversible sorption model were in fair agreement with observed data using parameter values within ranges recommended based on independent interpretations. The advection-dispersion-reversible sorption model is a large simplification of the system among other things because the partitioning of radionuclides between water and solid phase is described with a sorption equilibrium term only. Although the results from this study not are enough to validate simple performance assessment models in a strict sense, it has been shown that even simple models are able to describe the present day distribution of uranium in the weathered zone at Koongarra. 23 refs, 61 figs

The Alligator rivers natural analogue - Modelling of uranium and thorium migration in the weathered zone at Koongarra

Energy Technology Data Exchange (ETDEWEB)

Skagius, K; Lindgren, M; Boghammar, A; Brandberg, F; Pers, K; Widen, H [Kemakta, Stockholm (Sweden)

1993-08-01

The Koongarra Uranium Deposit in the Alligator Rivers Region in the Northern Territory of Australia is a natural analogue being investigated with the aim to contribute to the understanding of the scientific basis for the long term prediction of radionuclide migration within geological environments relevant to radioactive waste repositories. The dispersion of uranium and decay products in the weathered zone has been modelled with a simple advection-dispersion-reversible sorption model and with a model extended to also consider {alpha}-recoil and transfer of radionuclides between different mineral phases of the rock. The modelling work was carried out in several iterations, each including a review of available laboratory and field data, selection of the system to be modelled and suitable model, and a comparison of modelling results with field observations. Uranium concentrations in bulk rock calculated with the simple advection-dispersion- reversible sorption model were in fair agreement with observed data using parameter values within ranges recommended based on independent interpretations. The advection-dispersion-reversible sorption model is a large simplification of the system among other things because the partitioning of radionuclides between water and solid phase is described with a sorption equilibrium term only. Although the results from this study not are enough to validate simple performance assessment models in a strict sense, it has been shown that even simple models are able to describe the present day distribution of uranium in the weathered zone at Koongarra. 23 refs, 61 figs.

Electrochemo-hydrodynamics modeling approach for a uranium electrowinning cell

Energy Technology Data Exchange (ETDEWEB)

Kim, K.R.; Paek, S.; Ahn, D.H., E-mail: krkim1@kaeri.re.kr, E-mail: swpaek@kaeri.re.kr, E-mail: dhahn2@kaeri.re.kr [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, J.Y.; Hwang, I.S., E-mail: d486916@snu.ac.kr, E-mail: hisline@snu.ac.kr [Department of Nuclear Engineering, Seoul National University (Korea, Republic of)

2011-07-01

This study demonstrated a simulation based on fully coupling of electrochemical kinetics with 3- dimensional transport of ionic species in a flowing molten-salt electrolyte through a simplified channel cell of uranium electro winner. Dependences of ionic electro-transport on the velocity of stationary electrolyte flow were studied using a coupling approach of electrochemical reaction model. The present model was implemented in a commercially available computational fluid dynamics (CFD) platform, Ansys-CFX, using its customization ability via user defined functions. The main parameters characterizing the effect of the turbulent flow of an electrolyte between two planar electrodes were demonstrated by means of CFD-based multiphysics simulation approach. Simulation was carried out for the case of uranium electrowinning characteristics in a stream of molten salt electrolyte. This approach was taken into account the concentration profile at the electrode surface, to represent the variation of the diffusion limited current density as a function of the flow characteristics and of applied current density. It was able to predict conventional current voltage relation in addition to details of electrolyte fluid dynamics and electrochemical variable, such as flow field, species concentrations, potential, and current distributions throughout the current driven cell. (author)

Electrochemo-hydrodynamics modeling approach for a uranium electrowinning cell

International Nuclear Information System (INIS)

Kim, K.R.; Paek, S.; Ahn, D.H.; Park, J.Y.; Hwang, I.S.

2011-01-01

This study demonstrated a simulation based on fully coupling of electrochemical kinetics with 3- dimensional transport of ionic species in a flowing molten-salt electrolyte through a simplified channel cell of uranium electro winner. Dependences of ionic electro-transport on the velocity of stationary electrolyte flow were studied using a coupling approach of electrochemical reaction model. The present model was implemented in a commercially available computational fluid dynamics (CFD) platform, Ansys-CFX, using its customization ability via user defined functions. The main parameters characterizing the effect of the turbulent flow of an electrolyte between two planar electrodes were demonstrated by means of CFD-based multiphysics simulation approach. Simulation was carried out for the case of uranium electrowinning characteristics in a stream of molten salt electrolyte. This approach was taken into account the concentration profile at the electrode surface, to represent the variation of the diffusion limited current density as a function of the flow characteristics and of applied current density. It was able to predict conventional current voltage relation in addition to details of electrolyte fluid dynamics and electrochemical variable, such as flow field, species concentrations, potential, and current distributions throughout the current driven cell. (author)

Uranium

International Nuclear Information System (INIS)

Hamdoun, N.A.

2007-01-01

The article includes a historical preface about uranium, discovery of portability of sequential fission of uranium, uranium existence, basic raw materials, secondary raw materials, uranium's physical and chemical properties, uranium extraction, nuclear fuel cycle, logistics and estimation of the amount of uranium reserves, producing countries of concentrated uranium oxides and percentage of the world's total production, civilian and military uses of uranium. The use of depleted uranium in the Gulf War, the Balkans and Iraq has caused political and environmental effects which are complex, raising problems and questions about the effects that nuclear compounds left on human health and environment.

Comparison of two lung clearance models based on the dissolution rates of oxidized depleted uranium

Energy Technology Data Exchange (ETDEWEB)

Crist, K.C.

1984-10-01

An in-vitro dissolution study was conducted on two respirable oxidized depleted uranium samples. The dissolution rates generated from this study were then utilized in the International Commission on Radiological Protection Task Group lung clearance model and a lung clearance model proposed by Cuddihy. Predictions from both models based on the dissolution rates of the amount of oxidized depleted uranium that would be cleared to blood from the pulmonary region following an inhalation exposure were compared. It was found that the predictions made by both models differed considerably. The difference between the predictions was attributed to the differences in the way each model perceives the clearance from the pulmonary region. 33 references, 11 figures, 9 tables.

Comparison of two lung clearance models based on the dissolution rates of oxidized depleted uranium

International Nuclear Information System (INIS)

Crist, K.C.

1984-10-01

An in-vitro dissolution study was conducted on two respirable oxidized depleted uranium samples. The dissolution rates generated from this study were then utilized in the International Commission on Radiological Protection Task Group lung clearance model and a lung clearance model proposed by Cuddihy. Predictions from both models based on the dissolution rates of the amount of oxidized depleted uranium that would be cleared to blood from the pulmonary region following an inhalation exposure were compared. It was found that the predictions made by both models differed considerably. The difference between the predictions was attributed to the differences in the way each model perceives the clearance from the pulmonary region. 33 references, 11 figures, 9 tables

Adsorption of uranium(VI) to manganese oxides: X-ray absorption spectroscopy and surface complexation modeling.

Science.gov (United States)

Wang, Zimeng; Lee, Sung-Woo; Catalano, Jeffrey G; Lezama-Pacheco, Juan S; Bargar, John R; Tebo, Bradley M; Giammar, Daniel E

2013-01-15

The mobility of hexavalent uranium in soil and groundwater is strongly governed by adsorption to mineral surfaces. As strong naturally occurring adsorbents, manganese oxides may significantly influence the fate and transport of uranium. Models for U(VI) adsorption over a broad range of chemical conditions can improve predictive capabilities for uranium transport in the subsurface. This study integrated batch experiments of U(VI) adsorption to synthetic and biogenic MnO(2), surface complexation modeling, ζ-potential analysis, and molecular-scale characterization of adsorbed U(VI) with extended X-ray absorption fine structure (EXAFS) spectroscopy. The surface complexation model included inner-sphere monodentate and bidentate surface complexes and a ternary uranyl-carbonato surface complex, which was consistent with the EXAFS analysis. The model could successfully simulate adsorption results over a broad range of pH and dissolved inorganic carbon concentrations. U(VI) adsorption to synthetic δ-MnO(2) appears to be stronger than to biogenic MnO(2), and the differences in adsorption affinity and capacity are not associated with any substantial difference in U(VI) coordination.

Metallogenic characteristics, model and exploration prospect for the paleo-interlayer-oxidation type sandstone-hosted uranium deposits in China

International Nuclear Information System (INIS)

Huang Jingbai; Li Shengxiang

2007-01-01

In this paper, the paleo-interlayer-oxidation type sandstone-hosted uranium deposits occurred in the Meso-Cenozoic continental basins in China are divided into 3 subtype, they are stratum over lapping buried subtype, structure-uplifting destroy subtype and faulted-folding conserved subtype. The metallogenic characteristics, metallogenic model and exploration prospect for these 3 subtypes uranium deposits are discussed. It is proposed that the paleo-interlayer-oxidation type sandstone-hosted uranium deposits, besides the recent interlayer oxidation type sandstone-hosted uranium deposits, are of great prospecting potential in the Meso-Cenozoic continental basins in China. Therefore, the metallogenic theory of these types uranium deposits should be conscientiously summarized and replenished continuously so as to propel forward the exploration of the sandstone-hosted uranium deposits in China. (authors)

Removal of uranium from uranium plant wastewater using zero-valent iron in an ultrasonic field

Energy Technology Data Exchange (ETDEWEB)

Li, Jing; Zhang, Libo; Peng, Jinhui; Ma, Aiyuan; Xia, Hong Ying; Guo, Wen Qian; Yu, Xia [Yunnan Provincial Key Laboratory of Intensification Metallurgy, Kunming (China); Hu, Jinming; Yang, Lifeng [Nuclear Group Two Seven Two Uranium Industry Limited Liability Company, Hengyang (China)

2016-06-15

Uranium removal from uranium plant wastewater using zero-valent iron in an ultrasonic field was investigated. Batch experiments designed by the response surface methodology (RSM) were conducted to study the effects of pH, ultrasonic reaction time, and dosage of zero-valent iron on uranium removal efficiency. From the experimental data obtained in this work, it was found that the ultrasonic method employing zero-valent iron powder effectively removes uranium from uranium plant wastewater with a uranium concentration of 2,772.23 μg/L. The pH ranges widely from 3 to 7 in the ultrasonic field, and the prediction model obtained by the RSM has good agreement with the experimental results.

Uranium extraction from gold-uranium ores

Energy Technology Data Exchange (ETDEWEB)

Laskorin, B.N.; Golynko, Z.Sh.

1981-01-01

The process of uranium extraction from gold-uranium ores in the South Africa is considered. Flowsheets of reprocessing gold-uranium conglomerates, pile processing and uranium extraction from the ores are presented. Continuous counter flow ion-exchange process of uranium extraction using strong-active or weak-active resins is noted to be the most perspective and economical one. The ion-exchange uranium separation with the succeeding extraction is also the perspective one.

Method for converting uranium oxides to uranium metal

International Nuclear Information System (INIS)

Duerksen, W.K.

1988-01-01

A method for converting uranium oxide to uranium metal is described comprising the steps of heating uranium oxide in the presence of a reducing agent to a temperature sufficient to reduce the uranium oxide to uranium metal and form a heterogeneous mixture of a uranium metal product and oxide by-products, heating the mixture in a hydrogen atmosphere at a temperature sufficient to convert uranium metal in the mixture to uranium hydride, cooling the resulting uranium hydride-containing mixture to a temperature sufficient to produce a ferromagnetic transition in the uranium hydride, magnetically separating the cooled uranium hydride from the mixture, and thereafter heating the separated uranium hydride in an inert atmosphere to a temperature sufficient to convert the uranium hydride to uranium metal

Performance Assessment Transport Modeling of Uranium at the Area 5 Radioactive Waste Management Site at the Nevada National Security Site

International Nuclear Information System (INIS)

2010-01-01

Following is a brief summary of the assumptions that are pertinent to the radioactive isotope transport in the GoldSim Performance Assessment model of the Area 5 Radioactive Waste Management Site, with special emphasis on the water-phase reactive transport of uranium, which includes depleted uranium products. The Area 5 PA model assumes activity disposed in trenches is well mixed within the native alluvium of the trench at the time the facility is closed. Waste containers and waste forms are assumed not to limit the release of radionuclides for transport. In the Area 5 RWMS PA model, the pathways that are considered to bring radioactivity in the waste zone to the surface soils of the closure covers are (1) plant uptake, (2) burrowing animal activity, and (3) advection/dispersion/diffusion in the pore water. Water-phase transport is a minor component of the transport, which is dominated by plant uptake and burrowing animal activity. Because the soil column is mostly dry, upward water flux rates are extremely small, resulting in small advective/dispersive transport of radioactive isotopes in pore water of the unsaturated zone. Reactive transport of radioactive elements in the Area 5 soil pore water are modeled using element-specific partition coefficients (Kds) that partition radioactivity between pore water and soil of the disposal cell, and solubility limits that control the solubility of elements in pore water. Geochemical modeling is not performed in the Area 5 RWMS GoldSim PA model; however, Kds and solubility limits were derived from previous geochemical modeling performed using Area 5 geochemical data. Kds for uranium were developed based on geochemical modeling using the mineral characteristics of soil (alluvium) and the chemical characteristics of water at the site (Carle et al., 2002). In the GoldSim model, uranium Kd is represented with a lognormal distribution with a mean value of 0.8 milliliter per gram (taken from Figure 4.11, Page 4-19 of Carle et al

Fate and transport modelling of uranium in Port Hope Harbour

International Nuclear Information System (INIS)

Pinilla, C.E.; Garisto, N.; Peters, R.

2010-01-01

Fate and transport modelling of contaminants in Port Hope Harbour and near-shore Lake Ontario was undertaken in support of an ecological and human health risk assessment. Uranium concentrations in the Harbour and near-shore Lake Ontario due to groundwater and storm water loadings were estimated with a state-of-the-art 3D hydrodynamic and contaminant transport model (ECOMSED). The hydrodynamic model was simplified to obtain a first estimate of the flow pattern in the Harbour. The model was verified with field data using a tracer (fluoride). The modelling results generally showed good agreement with the tracer field data. (author)

Cellular localization of uranium in the renal proximal tubules during acute renal uranium toxicity.

Science.gov (United States)

Homma-Takeda, Shino; Kitahara, Keisuke; Suzuki, Kyoko; Blyth, Benjamin J; Suya, Noriyoshi; Konishi, Teruaki; Terada, Yasuko; Shimada, Yoshiya

2015-12-01

Renal toxicity is a hallmark of uranium exposure, with uranium accumulating specifically in the S3 segment of the proximal tubules causing tubular damage. As the distribution, concentration and dynamics of accumulated uranium at the cellular level is not well understood, here, we report on high-resolution quantitative in situ measurements by high-energy synchrotron radiation X-ray fluorescence analysis in renal sections from a rat model of uranium-induced acute renal toxicity. One day after subcutaneous administration of uranium acetate to male Wistar rats at a dose of 0.5 mg uranium kg(-1) body weight, uranium concentration in the S3 segment of the proximal tubules was 64.9 ± 18.2 µg g(-1) , sevenfold higher than the mean renal uranium concentration (9.7 ± 2.4 µg g(-1) ). Uranium distributed into the epithelium of the S3 segment of the proximal tubules and highly concentrated uranium (50-fold above mean renal concentration) in micro-regions was found near the nuclei. These uranium levels were maintained up to 8 days post-administration, despite more rapid reductions in mean renal concentration. Two weeks after uranium administration, damaged areas were filled with regenerating tubules and morphological signs of tissue recovery, but areas of high uranium concentration (100-fold above mean renal concentration) were still found in the epithelium of regenerating tubules. These data indicate that site-specific accumulation of uranium in micro-regions of the S3 segment of the proximal tubules and retention of uranium in concentrated areas during recovery are characteristics of uranium behavior in the kidney. Copyright © 2015 John Wiley & Sons, Ltd.

Modelling of the dissolution and reprecipitation of uranium under oxidising conditions in the zone of shallow groundwater circulation.

Science.gov (United States)

Dutova, Ekaterina M; Nikitenkov, Aleksei N; Pokrovskiy, Vitaly D; Banks, David; Frengstad, Bjørn S; Parnachev, Valerii P

2017-11-01

Generic hydrochemical modelling of a grantoid-groundwater system, using the Russian software "HydroGeo", has been carried out with an emphasis on simulating the accumulation of uranium in the aqueous phase. The baseline model run simulates shallow granitoid aquifers (U content 5 ppm) under conditions broadly representative of southern Norway and southwestern Siberia: i.e. temperature 10 °C, equilibrated with a soil gas partial CO 2 pressure (P CO2 , open system) of 10 -2.5 atm. and a mildly oxidising redox environment (Eh = +50 mV). Modelling indicates that aqueous uranium accumulates in parallel with total dissolved solids (or groundwater mineralisation M - regarded as an indicator of degree of hydrochemical evolution), accumulating most rapidly when M = 550-1000 mg L -1 . Accumulation slows at the onset of saturation and precipitation of secondary uranium minerals at M = c. 1000 mg L -1 (which, under baseline modelling conditions, also corresponds approximately to calcite saturation and transition to Na-HCO 3 hydrofacies). The secondary minerals are typically "black" uranium oxides of mixed oxidation state (e.g. U 3 O 7 and U 4 O 9 ). For rock U content of 5-50 ppm, it is possible to generate a wide variety of aqueous uranium concentrations, up to a maximum of just over 1 mg L -1 , but with typical concentrations of up to 10 μg L -1 for modest degrees of hydrochemical maturity (as indicated by M). These observations correspond extremely well with real groundwater analyses from the Altai-Sayan region of Russia and Norwegian crystalline bedrock aquifers. The timing (with respect to M) and degree of aqueous uranium accumulation are also sensitive to Eh (greater mobilisation at higher Eh), uranium content of rocks (aqueous concentration increases as rock content increases) and P CO2 (low P CO2 favours higher pH, rapid accumulation of aqueous U and earlier saturation with respect to uranium minerals). Copyright © 2017 Elsevier Ltd. All rights

Building Conceptual Models of Field-Scale Uranium Reactive Transport in a Dynamic Vadose Zone-Aquifer-River System

International Nuclear Information System (INIS)

Yabusaki, Steven B.; Fang, Yilin; Waichler, Scott R.

2008-01-01

Subsurface simulation is being used to build, test, and couple conceptual process models to better understand controls on a 0.4 km by 1.0 km uranium plume that has persisted above the drinking water standard in the groundwater of the Hanford 300 Area over the last 15 years. At this site, uranium-contaminated sediments in the vadose zone and aquifer are subject to significant variations in water levels and velocities driven by the diurnal, weekly, seasonal, and episodic Columbia River stage dynamics. Groundwater flow reversals typically occur twice a day with significant exchange of river water and groundwater in the near-river aquifer. Mixing of the dilute solution chemistry of the river with the groundwater complicates the uranium sorption behavior as the mobility of U(VI) has been shown experimentally to be a function of pH, carbonate, calcium, and uranium. Furthermore, uranium mass transfer between solid and aqueous phases has been observed to be rate-limited in the context of the high groundwater velocities resulting from the river stage fluctuations and the highly transmissive sediments (hydraulic conductivities ∼1500 m/d). One- and two-dimensional vertical cross-sectional simulations of variably-saturated flow and reactive transport, based on laboratory-derived models of distributed rate mass transfer and equilibrium multicomponent surface complexation, are used to assess uranium transport at the dynamic vadose zone aquifer interface as well as changes to uranium mobility due to incursions of river water into the aquifer

Predictive geochemical modeling of uranium and other contaminants in laboratory columns in relatively oxidizing, carbonate-rich solutions

International Nuclear Information System (INIS)

Longmire, P.; Turney, W.R.; Mason, C.F.V.

1994-01-01

Carbonate heap leaching of uranium-contaminated soils and sediments represents a viable, cost-effective remediation technology. Column experiments have been conducted using 0.1, 0.25, and 0.5 M Na 2 CO 3 /NaHCO 3 solutions for leaching uranium from soils located adjacent to an incinerator at the Fernald Environmental Management Project (FEMP) site. Results from column experiments and geochemical modeling are used to quantitatively evaluate the effectiveness of heap leaching. Leach efficiencies of up to 72 wt.% of total uranium in CaO-agglomerated soil result from dissolution of uranium (U(VI)-dominated) minerals, formation of the soluble complex UO 2 (CO 3 ) 3 4- , and uranium desorption from clay minerals, ferric hydroxides, and humic acids. Parameters that control the extent of uranium extraction include pH, Eh, temperature, carbonate concentration, lixiviant-flow rate, pore-solution chemistry, solid phases, and soil texture

Studying uranium migration in natural environment: experimental approach and geochemical modeling

International Nuclear Information System (INIS)

Phrommavanh, V.

2008-10-01

The present study deals with characterizing uranium migration in a limited zone of Le Bouchet site, a former uranium ore treatment facility, which is dismantled and the rehabilitation of which is under process. Some wastes are packed in a rehabilitated disposal nearby, called the Itteville site. In the framework of the monitoring of the deposit environment (air, water, sediment) set by prefectorial decrees, a piezometer (PZPK) located downstream to the latter, has shown total dissolved uranium peaks each winter since the 1990's. PZPK collects both the interstitial water of a calcareous peat formation, between the surface and 3 m, and an alluvial aquifer near 6 m of depth. Firstly, a hydrogeochemical characterization of the site has evidenced the uranium source term, which is present in the peat soil near 0.8 m, hence excluding any leaching from the waste disposal. Actually, a few microparticles of uranium oxide and mixed uranium-thorium oxide have been detected, but they do not represent the major part of the source term. Secondly, water chemistry of the peat soil water and PZPK has been monitored every two months from 2004 to 2007 in order to understand the reasons of the seasonal fluctuations of [U]tot.diss.. Completed with geochemical modeling and a bacterial identification by 16S rDNA sequence analysis, water chemistry data showed an important sulfate-reducing bacterial activity in summertime, leading to reducing conditions and therefore, a total dissolved uranium content limited by the low solubility of uraninite U IV O 2 (s). In wintertime, the latter bacterial activity being minimal and the effective pluviometry more important, conditions are more oxidant, which favors U(VI), more soluble, notably as the Ca 2 UO 2 (CO 3 ) 3 (aq) complex, evidenced by TRLFS. Finally, bacterial activity has been reproduced in laboratory in order to better characterize its impact on uranium solubility in the peat soil. Various parameters were tested (C sources, temperature

Uranium exploration techniques

International Nuclear Information System (INIS)

Nichols, C.E.

1984-01-01

The subject is discussed under the headings: introduction (genetic description of some uranium deposits; typical concentrations of uranium in the natural environment); sedimentary host rocks (sandstones; tabular deposits; roll-front deposits; black shales); metamorphic host rocks (exploration techniques); geologic techniques (alteration features in sandstones; favourable features in metamorphic rocks); geophysical techniques (radiometric surveys; surface vehicle methods; airborne methods; input surveys); geochemical techniques (hydrogeochemistry; petrogeochemistry; stream sediment geochemistry; pedogeochemistry; emanometry; biogeochemistry); geochemical model for roll-front deposits; geologic model for vein-like deposits. (U.K.)

The application of artificial neural network in radon disaster model of uranium mining

International Nuclear Information System (INIS)

Zhu Yufeng; Zhu Guogen; Zhou Shijian

2012-01-01

The structural features, data analysis and learning process of feed-forward neural network (BP ANN) were analyzed at first. Rodon sample from Fuzhou Jinan Uranium Industry Limited Company were used to training the network and make the forecast then, and a forecasting model was established for the radon disaster in uranium mines. The method and effectiveness of BP neural network in predicting radon disaster was discussed. The test of training samples showed that the BP network had gotten fairly satisfied result in predicting mine radon disaster. (authors)

Development of empirical relation for isotope of uranium in enriched uranium matrix

International Nuclear Information System (INIS)

Srivastava, S.K.; Vidyasagar, D.; Jha, S.K.; Tripathi, R.M.

2018-01-01

Uranium enriched in 235 U is required in commercial light water reactors to produce a controlled nuclear reaction. Enrichment allows the 235 U isotopes to be increased from 0.71% to a range between 2% to 5% depending upon requirement. The enriched uranium in the form of sintered UO 2 pellet is used for any commercially operating boiling light water reactors. The enriched uranium fuel bundle surface swipes sample is being analysed to assess the tramp uranium as a quality control parameter. It is known that the 234 U isotope also enriched along with 235 U isotope in conventional gaseous diffusion enrichment process. The information about enrichment percentage of 234 U helps to characterize isotopic properties of enriched uranium. A few reports provide the empirical equation and graphs for finding out the specific activity, activity percentage, activity ratio of 234 U isotopes for enriched uranium. Most of them have not provided the reference for the data used and their source. An attempt has been made to model the relationship between 234 U and 235 U as a function of uranium enrichment at low level

The end of cheap uranium

International Nuclear Information System (INIS)

Dittmar, Michael

2013-01-01

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

Method for converting uranium oxides to uranium metal

Science.gov (United States)

Duerksen, Walter K.

1988-01-01

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

Effect of the Changes of Respiratory Tract Model on the Uranium Bioassay Data

Energy Technology Data Exchange (ETDEWEB)

Kwon, Taeeun; Noh, Siwan; Kim, Meeryeong; Lee, Jaiki [Hanyang Univ., Seoul (Korea, Republic of); Lee, Jongil; Kim, Jang Lyul [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-05-15

The HRTM, however, was revised based on the recent experimental data in OIR (Occupational Intakes of Radionuclides) draft report of ICRP. The changes of respiratory tract model are predicted to directly affect bioassay data like retention and excretion functions. Lung retention function is especially important to internal exposure assessment for workers related to fuel manufacturing because the place could be contaminated by uranium. In addition, faecel samples are recommended to be used for in-vitro bioassay of uranium because of very slow excretion via urine. More reliable assessments for the workers in fuel manufacturing could be achieved by recalculation of bioassay data for uranium and the comparing study using original and revised HRTM. In this study, therefore, the lung retention and faecal excretion functions for inhalation of UO{sub 2} and U{sub 3}O{sub 8} were recalculated using revised HRTM and the results were compared with those of original HRTM. In this study the lung retention and faecal excretion functions for inhalation of UO{sub 2} and U{sub 3}O{sub 8} were calculated based on original and revised HRTM. The results show that the revised HRTM increases lung retention and uptakes to alimentary tract which cause the more faecal excretion. The results in this study confirm the effect of the changes of respiratory tract model on the uranium bioassay data although the more study is needed to apply to practical fields.

Uranium

International Nuclear Information System (INIS)

Cuney, M.; Pagel, M.; Leroy, J.

1992-01-01

First, this book presents the physico-chemical properties of Uranium and the consequences which can be deduced from the study of numerous geological process. The authors describe natural distribution of Uranium at different scales and on different supports, and main Uranium minerals. A great place in the book is assigned to description and classification of uranium deposits. The book gives also notions on prospection and exploitation of uranium deposits. Historical aspects of Uranium economical development (Uranium resources, production, supply and demand, operating costs) are given in the last chapter. 7 refs., 17 figs

A Point Kinetics Model for Estimating Neutron Multiplication of Bare Uranium Metal in Tagged Neutron Measurements

Science.gov (United States)

Tweardy, Matthew C.; McConchie, Seth; Hayward, Jason P.

2017-07-01

An extension of the point kinetics model is developed to describe the neutron multiplicity response of a bare uranium object under interrogation by an associated particle imaging deuterium-tritium (D-T) measurement system. This extended model is used to estimate the total neutron multiplication of the uranium. Both MCNPX-PoliMi simulations and data from active interrogation measurements of highly enriched and depleted uranium geometries are used to evaluate the potential of this method and to identify the sources of systematic error. The detection efficiency correction for measured coincidence response is identified as a large source of systematic error. If the detection process is not considered, results suggest that the method can estimate total multiplication to within 13% of the simulated value. Values for multiplicity constants in the point kinetics equations are sensitive to enrichment due to (n, xn) interactions by D-T neutrons and can introduce another significant source of systematic bias. This can theoretically be corrected if isotopic composition is known a priori. The spatial dependence of multiplication is also suspected of introducing further systematic bias for high multiplication uranium objects.

A dynamic uranium-leaching model for process-control studies

International Nuclear Information System (INIS)

Vetter, D.A.; Barker, I.J.; Turner, G.A.

1989-01-01

The modelling of the uranium-leaching process, and the logging of data from a plant for the evaluation of the model, are reported. A phenomenological approach was adopted in the development of the model. A set of eight chemical reactions was chosen to represent the complex chemistry of the process, and kinetic expressions for these reactions were incorporated in differential equations representing mass and energy balances. These equations were coded in FORTRAN to form a program that simulated the process, and that allowed averaged and continuous data from the plant to be compared with the model. This allowed the model to be 'tuned', and to reveal a number of minor problems with the control infrastructure on the plant. 7 figs., 21 refs

Uranium Resources Modeling And Estimation In Lembah Hitam Sector, Kalan, West Kalimantan

International Nuclear Information System (INIS)

Adi Gunawan Muhammad; Bambang Soetopo

2016-01-01

Lembah Hitam Sector is part of Schwaner Mountains and Kalan Basin upper part stratigraphy. Uranium (U) mineralization layer is associated with metasiltstone and metapelites schistose heading to N 265° E/60° S. Evaluation drilling carried out with a distance of 50 m from an existing point (FKL 14 and FKL 13) to determine the model and the amount of U resources in measured category. To achieve these objectives some activities including reviewing the previous studies, geological and U mineralization data collecting, grades quantitative estimation using log gross-count gamma ray, database and modeling creation and resource estimation of U carried out. Based on modeling on ten drilling data and completed with drilled core observation, the average grade of U mineralization in Lembah Hitam Sector obtained. The average grade is ranging from 0.0076 - 0.95 % eU_3O_8, with a thickness of mineralization ranging from 0.1 - 4.5 m. Uranium mineralization present as fracture filling (veins) or groups of veins and as matrix filling in tectonic breccia, associated with pyrite, pyrrhotite, magnetite, molybdenite, tourmaline and quartz in metasiltstone and metapelites schistose. Calculation of U resources to 26 ores body using 25 m searching radius resulted in 655.65 tons ores. By using 0.01 % cut-off grade resulted in 546.72 tons ores with an average grade 0.101 % eU_3O_8. Uranium resource categorized as low-grade measured resources. (author)

Uranium

International Nuclear Information System (INIS)

Poty, B.; Cuney, M.; Bruneton, P.; Virlogeux, D.; Capus, G.

2010-01-01

With the worldwide revival of nuclear energy comes the question of uranium reserves. For more than 20 years, nuclear energy has been neglected and uranium prospecting has been practically abandoned. Therefore, present day production covers only 70% of needs and stocks are decreasing. Production is to double by 2030 which represents a huge industrial challenge. The FBR-type reactors technology, which allows to consume the whole uranium content of the fuel, is developing in several countries and will ensure the long-term development of nuclear fission. However, the implementation of these reactors (the generation 4) will be progressive during the second half of the 21. century. For this reason an active search for uranium ores will be necessary during the whole 21. century to ensure the fueling of light water reactors which are huge uranium consumers. This dossier covers all the aspects of natural uranium production: mineralogy, geochemistry, types of deposits, world distribution of deposits with a particular attention given to French deposits, the exploitation of which is abandoned today. Finally, exploitation, ore processing and the economical aspects are presented. Contents: 1 - the uranium element and its minerals: from uranium discovery to its industrial utilization, the main uranium minerals (minerals with tetravalent uranium, minerals with hexavalent uranium); 2 - uranium in the Earth's crust and its geochemical properties: distribution (in sedimentary rocks, in magmatic rocks, in metamorphic rocks, in soils and vegetation), geochemistry (uranium solubility and valence in magmas, uranium speciation in aqueous solution, solubility of the main uranium minerals in aqueous solution, uranium mobilization and precipitation); 3 - geology of the main types of uranium deposits: economical criteria for a deposit, structural diversity of deposits, classification, world distribution of deposits, distribution of deposits with time, superficial deposits, uranium

Reactive transport modeling of uranium 238 and radium 226 in groundwater of the Königstein uranium mine, Germany

Science.gov (United States)

Nitzsche, O.; Merkel, B.

Knowledge of the transport behavior of radionuclides in groundwater is needed for both groundwater protection and remediation of abandoned uranium mines and milling sites. Dispersion, diffusion, mixing, recharge to the aquifer, and chemical interactions, as well as radioactive decay, should be taken into account to obtain reliable predictions on transport of primordial nuclides in groundwater. This paper demonstrates the need for carrying out rehabilitation strategies before closure of the Königstein in-situ leaching uranium mine near Dresden, Germany. Column experiments on drilling cores with uranium-enriched tap water provided data about the exchange behavior of uranium. Uranium breakthrough was observed after more than 20 pore volumes. This strong retardation is due to the exchange of positively charged uranium ions. The code TReAC is a 1-D, 2-D, and 3-D reactive transport code that was modified to take into account the radioactive decay of uranium and the most important daughter nuclides, and to include double-porosity flow. TReAC satisfactorily simulated the breakthrough curves of the column experiments and provided a first approximation of exchange parameters. Groundwater flow in the region of the Königstein mine was simulated using the FLOWPATH code. Reactive transport behavior was simulated with TReAC in one dimension along a 6000-m path line. Results show that uranium migration is relatively slow, but that due to decay of uranium, the concentration of radium along the flow path increases. Results are highly sensitive to the influence of double-porosity flow. Résumé La protection des eaux souterraines et la restauration des sites miniers et de prétraitement d'uranium abandonnés nécessitent de connaître le comportement des radionucléides au cours de leur transport dans les eaux souterraines. La dispersion, la diffusion, le mélange, la recharge de l'aquifère et les interactions chimiques, de même que la décroissance radioactive, doivent être

Solubility of airborne uranium samples from uranium processing plant

International Nuclear Information System (INIS)

Kravchik, T.; Oved, S.; Sarah, R.; Gonen, R.; Paz-Tal, O.; Pelled, O.; German, U.; Tshuva, A.

2005-01-01

Full text: During the production and machining processes of uranium metal, aerosols might be released to the air. Inhalation of these aerosols is the main route of internal exposure of workers. To assess the radiation dose from the intake of these uranium compounds it is necessary to know their absorption type, based on their dissolution rate in extracellular aqueous environment of lung fluid. The International Commission on Radiological Protection (ICRP) has assigned UF4 and U03 to absorption type M (blood absorption which contains a 10 % fraction with an absorption rate of 10 minutes and 90 % fraction with an absorption rate of 140 fays) and UO2 and U3O8 to absorption type S (blood absorption rate with a half-time of 7000 days) in the ICRP-66 model.The solubility classification of uranium compounds defined by the ICRP can serve as a general guidance. At specific workplaces, differences can be encountered, because of differences in compounds production process and the presence of additional compounds, with different solubility characteristics. According to ICRP recommendations, material-specific rates of absorption should be preferred to default parameters whenever specific experimental data exists. Solubility profiles of uranium aerosols were determined by performing in vitro chemical solubility tests on air samples taken from uranium production and machining facilities. The dissolution rate was determined over 100 days in a simultant solution of the extracellular airway lining fluid. The filter sample was immersed in a test vial holding 60 ml of simultant fluid, which was maintained at a 37 o C inside a thermostatic bath and at a physiological pH of 7.2-7.6. The test vials with the solution were shaken to simulate the conditions inside the extracellular aqueous environment of the lung as much as possible. The tests indicated that the uranium aerosols samples taken from the metal production and machining facilities at the Nuclear Research Center Negev (NRCN

Preparation, characterization, uranium (VI) biosorption models, and conditions optimization by response surface methodology (RSM) for amidoxime-functionalized marine fungus materials

Energy Technology Data Exchange (ETDEWEB)

Yang, Xuechun; Gao, Yang; Jiang, Min; He, Dianxiong; Liao, Sen; Hou, Dan; Yan, Xueming; Long, Wei; Wu, Yaxin; Tan, Ni [Univ. of South China, Hengyang (China). School of Chemistry and Chemical Engineering

2017-08-01

Amidoxime-functionalized marine fungus Fusarium sp. ZZF51 (ZGDA) was synthesized and studied to adsorb uranium (VI) from the aqueous solution. Different instrumental techniques such as FTIR, SEM, and TGA were employed for the characterization of the manufactured materials, and theirs ability of removal uranium (VI) was optimized using RSM. The experimental results showed the maximum adsorption capacity for the synthesized materials was 230.78 mg g{sup -1} at the following optimization conditions: S-L ratio 150 mg L{sup -1}, pH 5.13, uranium (VI) initial concentration 40 mg L{sup -1}, and equilibrium time 122.40 min. More than 85% of the absorbed uranium (VI) could be desorbed by 0.5 or 1.0 mol L{sup -1} HCl, and the modified mycelium could be reused at least five times. The thermodynamic experimental data of adsorption uranium (VI) could fit better with Langmuir and Freundlich isotherms models, and the pseudo-second-order model was better to interpret the kinetics process. The modified fungus materials exhibited the better sorption capacity for uranium (VI) in comparison with raw biomass should be attributed to the strong chelation of amidoxime to uranium (VI) ions.

Conceptual Model of Uranium in the Vadose Zone for Acidic and Alkaline Wastes Discharged at the Hanford Site Central Plateau

Energy Technology Data Exchange (ETDEWEB)

Truex, Michael J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Szecsody, James E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Qafoku, Nikolla [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Serne, R. Jeffrey [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2014-09-01

Historically, uranium was disposed in waste solutions of varying waste chemistry at the Hanford Site Central Plateau. The character of how uranium was distributed in the vadose zone during disposal, how it has continued to migrate through the vadose zone, and the magnitude of potential impacts on groundwater are strongly influenced by geochemical reactions in the vadose zone. These geochemical reactions can be significantly influenced by the disposed-waste chemistry near the disposal location. This report provides conceptual models and supporting information to describe uranium fate and transport in the vadose zone for both acidic and alkaline wastes discharged at a substantial number of waste sites in the Hanford Site Central Plateau. The conceptual models include consideration of how co-disposed acidic or alkaline fluids influence uranium mobility in terms of induced dissolution/precipitation reactions and changes in uranium sorption with a focus on the conditions near the disposal site. This information, when combined with the extensive information describing uranium fate and transport at near background pH conditions, enables focused characterization to support effective fate and transport estimates for uranium in the subsurface.

The importance of speculative uranium deposits

International Nuclear Information System (INIS)

Kaiser, H.; Roth-Seefrid, H.

1980-01-01

Since current known uranium deposits (5 million t U) will either have been exhausted by the end of the century, or must be held in reserve for the thermal converter reactors which will be in operation by that time, the development of nuclear energy after the year 2000 will depend to a large extent on the early availability of speculative uranium deposits. The speculative deposits represent, by definition, the quantities of uranium which are presumed to exist in addition to the 'known' deposits and which can ultimately be exploited according to current technical-economic and ecological standpoints. When viewed critically, however, the US-DOE model used for this purpose projects an over-optimistic picture of uranium supplies and was, therefore, only accepted by the INFCE with a series of limitations and reservations. Overall the model represents a well-founded reassurance for future uranium exploration - nothing more and nothing less. The model clearly shows that due to the long lead-in times considerable expenditure will be required for uranium exploration in the coming years. It is probable that this level of investment will have to be increased several times over in the 1990s as the search moves to greater depths and to less-accessible regions. (orig./UA) [de

Undiscovered Resource Modelling: Towards Applying a Systematic Approach to Uranium or How Much Uranium is Left and Where Might It Be Found?

International Nuclear Information System (INIS)

Fairclough, Martin; Katona, Laz

2014-01-01

Uranium Resource Modelling: Why do we want to plan for it? Purely from a supply-demand perspective: 1) Current supplies (at mid-range demand scenario) only enough until 2035 (likely to increase due to reactor shut down/stockpiling); 2) Not all uranium will be brought into production; 3) Long lead in times (particularly) for U mines; 4) Projections to 2060 (beyond IR) e.g IAEA TECDOC). From a socio-economic perspective: 1) Need for financial analysis; 2) Need for comparison with other land uses; 3) Need for comparison with other tracts of land; 4) Need for consideration of economic/environmental consequences of possible development; 5) Security of supply!!!

Technico-Economical study of retreated uranium reenrichment

International Nuclear Information System (INIS)

Patillon, L.

1985-03-01

Spent fuel from nuclear power plants is reprocessed at La Hague reprocessing plant in France. Recovered and stored reprocessed uranium has an energy potential unutilized so far. A modelisation is proposed in this paper for evaluating the economic interest reprocessed uranium reenrichment for using it again in a power plant. After briefly recalling the fuel cycle in light water reactors and reprocessed uranium specificities, a mathematical model for multi-isotope enrichment gives a differential system governing isotopic separation. Different solutions are proposed and compared. A. de la Garza analytical model's is retained. An economic value is attributed to reprocessed uranium. Results are presented as curves for determining the sensitivity of this value to simulation parameters (natural uranium cost, enrichment required by the electricity board etc.) [fr

Extraction and desorption of accessible uranium

International Nuclear Information System (INIS)

Payne, T.

1987-01-01

The proportion of the uranium in natural ore samples which is in isotopic equilibrium with the uranium in the groundwater may be designated accessible uranium, and can be regarded as being in short-term exchange with the aqueous phase. Some of the natural uranium is secured in resistant crystalline minerals, and is described as inaccessible, because it may not be brought into solution unless the mineral is subjected to extreme chemical attack. It is not available for groundwater transport in the short term. An estimate of the proportion of accessible uranium is therefore useful when modeling radionuclide migration. The amount of accessible natural uranium is some uranium ore samples from the Ranger deposit has been determined by combining a sequential extraction with isotopic measurements of the extracted phases. The solid samples were crushed drill core form Ranger S1/146 which had previously been used for uranium adsorption experiments and therefore contained 236 U as well as natural uranium. This Section discusses how the uranium partitioning found with the sequential extraction procedure predicts the leaching behavior of these samples

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

International Nuclear Information System (INIS)

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

2011-01-01

Field experiments at a former uranium mill tailings site have identified the potential for stimulating indigenous bacteria to catalyze the conversion of aqueous uranium in the +6 oxidation state to immobile solid-associated uranium in the +4 oxidation state. This effectively removes uranium from solution resulting in groundwater concentrations below actionable standards. Three-dimensional, coupled variably-saturated flow and biogeochemical reactive transport modeling of a 2008 in situ uranium bioremediation field experiment is used to better understand the interplay of transport rates and biogeochemical reaction rates that determine the location and magnitude of key reaction products. A comprehensive reaction network, developed largely through previous 1-D modeling studies, was used to simulate the impacts on uranium behavior of pulsed acetate amendment, seasonal water table variation, spatially-variable physical (hydraulic conductivity, porosity) and geochemical (reactive surface area) material properties. A principal challenge is the mechanistic representation of biologically-mediated terminal electron acceptor process (TEAP) reactions whose products significantly alter geochemical controls on uranium mobility through increases in pH, alkalinity, exchangeable cations, and highly reactive reduction products. In general, these simulations of the 2008 Big Rusty acetate biostimulation field experiment in Rifle, Colorado confirmed previously identified behaviors including (1) initial dominance by iron reducing bacteria that concomitantly reduce aqueous U(VI), (2) sulfate reducing bacteria that become dominant after ∼30 days and outcompete iron reducers for the acetate electron donor, (3) continuing iron-reducer activity and U(VI) bioreduction during dominantly sulfate reducing conditions, and (4) lower apparent U(VI) removal from groundwater during dominantly sulfate reducing conditions. New knowledge on simultaneously active metal and sulfate reducers has been

Uranium conversion

International Nuclear Information System (INIS)

Oliver, Lena; Peterson, Jenny; Wilhelmsen, Katarina

2006-03-01

FOI, has performed a study on uranium conversion processes that are of importance in the production of different uranium compounds in the nuclear industry. The same conversion processes are of interest both when production of nuclear fuel and production of fissile material for nuclear weapons are considered. Countries that have nuclear weapons ambitions, with the intention to produce highly enriched uranium for weapons purposes, need some degree of uranium conversion capability depending on the uranium feed material available. This report describes the processes that are needed from uranium mining and milling to the different conversion processes for converting uranium ore concentrate to uranium hexafluoride. Uranium hexafluoride is the uranium compound used in most enrichment facilities. The processes needed to produce uranium dioxide for use in nuclear fuel and the processes needed to convert different uranium compounds to uranium metal - the form of uranium that is used in a nuclear weapon - are also presented. The production of uranium ore concentrate from uranium ore is included since uranium ore concentrate is the feed material required for a uranium conversion facility. Both the chemistry and principles or the different uranium conversion processes and the equipment needed in the processes are described. Since most of the equipment that is used in a uranium conversion facility is similar to that used in conventional chemical industry, it is difficult to determine if certain equipment is considered for uranium conversion or not. However, the chemical conversion processes where UF 6 and UF 4 are present require equipment that is made of corrosion resistant material

Uranium: biokinetics and toxicity; Biocinetique et toxicite de l'uranium

Energy Technology Data Exchange (ETDEWEB)

Menetrier, F.; Renaud-Salis, V.; Flury-Herard, A

2000-07-01

This report was achieved as a part of a collaboration with the Fuel Cycle Direction. Its aim was to give the state of the art about: the behaviour of uranium in the human organism (biokinetics) after ingestion, its toxicity (mainly renal) and the current regulation about its incorporation. Both in the upstream and in the downstream of the fuel cycle, uranium remains, quantitatively, the first element in the cycle which is, at the present time, temporarily disposed or recycled. Such a considerable quantity of uranium sets the problem of its risk on the health. In the long term, the biosphere may be affected and consequently the public may ingest water or food contaminated with uranium. In this way, radiological and chemical toxicity risk may be activated. This report emphasizes: the necessity of confirming some experimental and epidemiological biokinetic data used or not in the ICRP models. Unsolved questions remain about the gastrointestinal absorption according to chemical form (valency state, mixtures...), mass and individual variations (age, disease) further a chronic ingestion of uranium. It is well established that uranium is mainly deposited in the skeleton and the kidney. But the skeleton kinetics following a chronic ingestion and especially in some diseases has to be more elucidated; the necessity of taking into account uranium at first as a chemical toxic, essentially in the kidney and determining the threshold of functional lesion. In this way, it is important to look for some specific markers; the problem of not considering chemical toxicity of uranium in the texts regulating its incorporation.

Aftermath of Uranium Ore Processing on Floodplains: Lasting Effects of Uranium on Soil and Microbes

Science.gov (United States)

Tang, H.; Boye, K.; Bargar, J.; Fendorf, S. E.

2016-12-01

A former uranium ore processing site located between the Wind River and the Little Wind River near the city of Riverton, Wyoming, has generated a uranium plume in the groundwater within the floodplain. Uranium is toxic and poses a threat to human health. Thus, controlling and containing the spread of uranium will benefit the human population. The primary source of uranium was removed from the processing site, but a uranium plume still exists in the groundwater. Uranium in its reduced form is relatively insoluble in water and therefore is retained in organic rich, anoxic layers in the subsurface. However, with the aid of microbes uranium becomes soluble in water which could expose people and the environment to this toxin, if it enters the groundwater and ultimately the river. In order to better understand the mechanisms controlling uranium behavior in the floodplains, we examined sediments from three sediment cores (soil surface to aquifer). We determined the soil elemental concentrations and measured microbial activity through the use of several instruments (e.g. Elemental Analyzer, X-ray Fluorescence, MicroResp System). Through the data collected, we aim to obtain a better understanding of how the interaction of geochemical factors and microbial metabolism affect uranium mobility. This knowledge will inform models used to predict uranium behavior in response to land use or climate change in floodplain environments.

Machining of uranium and uranium alloys

International Nuclear Information System (INIS)

Morris, T.O.

1981-01-01

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

Uranium recovery from slags of metallic uranium

International Nuclear Information System (INIS)

Fornarolo, F.; Frajndlich, E.U.C.; Durazzo, M.

2006-01-01

The Center of the Nuclear Fuel of the Institute of Nuclear Energy Research - IPEN finished the program of attainment of fuel development for research reactors the base of Uranium Scilicet (U 3 Si 2 ) from Hexafluoride of Uranium (UF 6 ) with enrichment 20% in weight of 235 U. In the process of attainment of the league of U 3 Si 2 we have as Uranium intermediate product the metallic one whose attainment generates a slag contend Uranium. The present work shows the results gotten in the process of recovery of Uranium in slags of calcined slags of Uranium metallic. Uranium the metallic one is unstable, pyrophoricity and extremely reactive, whereas the U 3 O 8 is a steady oxide of low chemical reactivity, what it justifies the process of calcination of slags of Uranium metallic. The calcination of the Uranium slag of the metallic one in oxygen presence reduces Uranium metallic the U 3 O 8 . Experiments had been developed varying it of acid for Uranium control and excess, nitric molar concentration gram with regard to the stoichiometric leaching reaction of temperature of the leaching process. The 96,0% income proves the viability of the recovery process of slags of Uranium metallic, adopting it previous calcination of these slags in nitric way with low acid concentration and low temperature of leaching. (author)

Uranium, depleted uranium, biological effects; Uranium, uranium appauvri, effets biologiques

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-07-01

Physicists, chemists and biologists at the CEA are developing scientific programs on the properties and uses of ionizing radiation. Since the CEA was created in 1945, a great deal of research has been carried out on the properties of natural, enriched and depleted uranium in cooperation with university laboratories and CNRS. There is a great deal of available data about uranium; thousands of analyses have been published in international reviews over more than 40 years. This presentation on uranium is a very brief summary of all these studies. (author)

Re-examining uranium supply and demand: New insights

International Nuclear Information System (INIS)

Kahouli, Sondes

2011-01-01

In this paper, we derive a simultaneous system of equations which aims at analysing the uranium supply and demand. In addition to reviewing and updating previous studies dealing with the uranium market analysis, in particular , the contribution of the paper lies in putting attention to some questions which are still either controversial or unanswered. They are especially related to the controversial hypothesis of the interdependence between uranium market and other commodities markets, both, with respect to the demand side, i.e. oil and coal markets, and the supply side, i.e. gold market. The paper also casts lights on electricity and uranium price effects on uranium demand as well as on the simultaneous interdependencies that may exist between nuclear consumption and nuclear installed capacity. The model is estimated for three different time periods which takes into account the major events that have influenced the nuclear-uranium development, that is, that have constrained the growth rate of nuclear generating capacity, i.e. oil crisis and nuclear accidents. This permits to show if uranium market reaction is independent or it is correlated with specific events associated with each time periods. The model was estimated by using the 3SLS method that correct for the presence of contemporaneously error terms correlation and for the existence of simultaneity bias in the model. Main results give evidence of significant correlation between uranium price and competing fossil fuel prices. They also point-out that uranium price is significantly correlated with the supply forces where supply is significantly dependent on gold prices. Moreover, results show that the electricity prices have a significant effect on the uranium demand only in the post-1990 period, probably following the worldwide electricity prices increasing trend. Further, our estimations show that uranium demand is significantly correlated with uranium price only in the period of nuclear major expansion. As

Re-examining uranium supply and demand: New insights

Energy Technology Data Exchange (ETDEWEB)

Kahouli, Sondes, E-mail: sondes.kahouli@univ-nantes.f [Universite de Nantes, Laboratoire d' Economie et de Management de Nantes Atlantique (LEMNA), Institut d' Economie et de Management de Nantes-I.A.E., Chemin de la Censive du Tertre-B.P. 52231, 44322 Nantes Cedex 3 (France)

2011-01-15

In this paper, we derive a simultaneous system of equations which aims at analysing the uranium supply and demand. In addition to reviewing and updating previous studies dealing with the uranium market analysis, in particular , the contribution of the paper lies in putting attention to some questions which are still either controversial or unanswered. They are especially related to the controversial hypothesis of the interdependence between uranium market and other commodities markets, both, with respect to the demand side, i.e. oil and coal markets, and the supply side, i.e. gold market. The paper also casts lights on electricity and uranium price effects on uranium demand as well as on the simultaneous interdependencies that may exist between nuclear consumption and nuclear installed capacity. The model is estimated for three different time periods which takes into account the major events that have influenced the nuclear-uranium development, that is, that have constrained the growth rate of nuclear generating capacity, i.e. oil crisis and nuclear accidents. This permits to show if uranium market reaction is independent or it is correlated with specific events associated with each time periods. The model was estimated by using the 3SLS method that correct for the presence of contemporaneously error terms correlation and for the existence of simultaneity bias in the model. Main results give evidence of significant correlation between uranium price and competing fossil fuel prices. They also point-out that uranium price is significantly correlated with the supply forces where supply is significantly dependent on gold prices. Moreover, results show that the electricity prices have a significant effect on the uranium demand only in the post-1990 period, probably following the worldwide electricity prices increasing trend. Further, our estimations show that uranium demand is significantly correlated with uranium price only in the period of nuclear major expansion. As

Re-examining uranium supply and demand. New insights

Energy Technology Data Exchange (ETDEWEB)

Kahouli, Sondes [Universite de Nantes, Laboratoire d' Economie et de Management de Nantes Atlantique (LEMNA), Institut d' Economie et de Management de Nantes - I.A.E., Chemin de la Censive du Tertre - B.P. 52231, 44322 Nantes Cedex 3 (France)

2011-01-15

In this paper, we derive a simultaneous system of equations which aims at analysing the uranium supply and demand. In addition to reviewing and updating previous studies dealing with the uranium market analysis, in particular, the contribution of the paper lies in putting attention to some questions which are still either controversial or unanswered. They are especially related to the controversial hypothesis of the interdependence between uranium market and other commodities markets, both, with respect to the demand side, i.e. oil and coal markets, and the supply side, i.e. gold market. The paper also casts lights on electricity and uranium price effects on uranium demand as well as on the simultaneous interdependencies that may exist between nuclear consumption and nuclear installed capacity. The model is estimated for three different time periods which takes into account the major events that have influenced the nuclear-uranium development, that is, that have constrained the growth rate of nuclear generating capacity, i.e. oil crisis and nuclear accidents. This permits to show if uranium market reaction is independent or it is correlated with specific events associated with each time periods. The model was estimated by using the 3SLS method that correct for the presence of contemporaneously error terms correlation and for the existence of simultaneity bias in the model. Main results give evidence of significant correlation between uranium price and competing fossil fuel prices. They also point-out that uranium price is significantly correlated with the supply forces where supply is significantly dependent on gold prices. Moreover, results show that the electricity prices have a significant effect on the uranium demand only in the post-1990 period, probably following the worldwide electricity prices increasing trend. Further, our estimations show that uranium demand is significantly correlated with uranium price only in the period of nuclear major expansion. As

Flotation of uranium from uranium ores in Canada. Part 2

International Nuclear Information System (INIS)

Muthuswami, S.V.; Vijayan, S.; Woods, D.R.

1985-01-01

Measurements are reported for the equilibrium of cupferron from solutions by uranium oxide, quartz, illite, a mixture of these three, pitchblende, pyrite and brannerite ore. The cupferron concentration ranged from 1 to 6 g/L, and the pH was 7 and 8. Most isotherms followed the Langmuir model, although Freundlich behaviour was observed for illite and pitchblende. Most adsorption was pH independent except for illite and pitchblende. The adsorption isotherms for a mixture of uranium oxide, quartz and illite in the same proportions as in the naturally occurring ore agreed with the adsorption of the pyrite-free ore at pH 8 but not pH 7. We attribute the discrepancy to the use of illite as the model clay. The specific adsorption of cupferron on quartz and illite is lower by a factor of about 50 and 5, respectively, than the adsorption on uranium oxide. Specific adsorption less than 1 mg cupferron per gm of pyrite free ore does not float the mineral. The corresponding equilibrium concentration of cupferron is 0.5 g/L. A qualitative model is given, and the implications of this work for practical operations are presented

230Th-234U Model-Ages of Some Uranium Standard Reference Materials

International Nuclear Information System (INIS)

Williams, R.W.; Gaffney, A.M.; Kristo, M.J.; Hutcheon, I.D.

2009-01-01

The 'age' of a sample of uranium is an important aspect of a nuclear forensic investigation and of the attribution of the material to its source. To the extent that the sample obeys the standard rules of radiochronometry, then the production ages of even very recent material can be determined using the 230 Th- 234 U chronometer. These standard rules may be summarized as (a) the daughter/parent ratio at time=zero must be known, and (b) there has been no daughter/parent fractionation since production. For most samples of uranium, the 'ages' determined using this chronometer are semantically 'model-ages' because (a) some assumption of the initial 230 Th content in the sample is required and (b) closed-system behavior is assumed. The uranium standard reference materials originally prepared and distributed by the former US National Bureau of Standards and now distributed by New Brunswick Laboratory as certified reference materials (NBS SRM = NBL CRM) are good candidates for samples where both rules are met. The U isotopic standards have known purification and production dates, and closed-system behavior in the solid form (U 3 O 8 ) may be assumed with confidence. We present here 230 Th- 234 U model-ages for several of these standards, determined by isotope dilution mass spectrometry using a multicollector ICP-MS, and compare these ages with their known production history

A Point Kinetics Model for Estimating Neutron Multiplication of Bare Uranium Metal in Tagged Neutron Measurements

International Nuclear Information System (INIS)

Tweardy, Matthew C.; McConchie, Seth; Hayward, Jason P.

2017-01-01

An extension of the point kinetics model is developed in this paper to describe the neutron multiplicity response of a bare uranium object under interrogation by an associated particle imaging deuterium-tritium (D-T) measurement system. This extended model is used to estimate the total neutron multiplication of the uranium. Both MCNPX-PoliMi simulations and data from active interrogation measurements of highly enriched and depleted uranium geometries are used to evaluate the potential of this method and to identify the sources of systematic error. The detection efficiency correction for measured coincidence response is identified as a large source of systematic error. If the detection process is not considered, results suggest that the method can estimate total multiplication to within 13% of the simulated value. Values for multiplicity constants in the point kinetics equations are sensitive to enrichment due to (n, xn) interactions by D-T neutrons and can introduce another significant source of systematic bias. This can theoretically be corrected if isotopic composition is known a priori. Finally, the spatial dependence of multiplication is also suspected of introducing further systematic bias for high multiplication uranium objects.

The toxicology of uranium compounds

International Nuclear Information System (INIS)

Brickner, D.

1988-11-01

This review of literature presents and criticises the current knowledge relevant to risk assessment in cases of human exposure to natural uranium compounds due to industrial accidents. The major risk of high uranium exposure is renal-tubular damage which may lead to acute renal insufficiency and death. Radiation damage is not expected in these circumstances. In this review the metabolism of uranium in the body, the health effects and the possible medical treatment are discussed, with an emphasis on relatively large exposure of short duration. The current ICRP lung model does not represent all the factors affecting the kinetics of uranium oxides in the respiratory tract. The significance of these factors, not represented by the model, for risk assessment in such exposures, is not known. The current recommendations for treatment are not scientifically based. Further investigations are urgently needed to enable a rational medical preparadness

Uranium internal exposure evaluation based on urine assay data

International Nuclear Information System (INIS)

Lawrence, J.N.P.

1984-09-01

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

Possible uranium sources of Streltsovsky uranium ore field

International Nuclear Information System (INIS)

Zhang Lisheng

2005-01-01

The uranium deposit of the Late Jurassic Streltsovaky caldera in Transbaikalia of Russia is the largest uranium field associated with volcanics in the world, its uranium reserves are 280 000 t U, and it is the largest uranium resources in Russia. About one third of the caldera stratigraphic pile consists of strongly-altered rhyolites. Uranium resources of the Streltsovsky caldera are much larger than any other volcanic-related uranium districts in the world. Besides, the efficiency of hydrothermal alteration, uranium resources appear to result from the juxtaposition of two major uranium sources; highly fractionated peralkaline rhyolites of Jurassic age in the caldera, and U-rich subalkaline granites of Variscan age in the basement in which the major uranium-bearing accessory minerals were metamict at the time of the hydrothermal ore formation. (authors)

Biosorption of uranium by chemically modified Rhodotorula glutinis

International Nuclear Information System (INIS)

Bai Jing; Yao Huijun; Fan Fangli; Lin Maosheng; Zhang Lina; Ding Huajie; Lei Fuan; Wu Xiaolei; Li, Xiaofei; Guo Junsheng; Qin Zhi

2010-01-01

The present paper reports the biosorption of uranium onto chemically modified yeast cells, Rhodotorula glutinis, in order to study the role played by various functional groups in the cell wall. Esterification of the carboxyl groups and methylation of the amino groups present in the cells were carried out by methanol and formaldehyde treatment, respectively. The uranium sorption capacity increased 31% for the methanol-treated biomass and 11% for the formaldehyde-treated biomass at an initial uranium concentration of 140 mg/L. The enhancement of uranium sorption capacity was investigated by Fourier transform infrared (FTIR) spectroscopy analysis, with amino and carboxyl groups were determined to be the important functional groups involved in uranium binding. The biosorption isotherms of uranium onto the raw and chemically modified biomass were also investigated with varying uranium concentrations. Langmuir and Freundlich models were well able to explain the sorption equilibrium data with satisfactory correlation coefficients higher than 0.9. -- Research highlights: → Uranium biosorption on to chemically modified yeast cells → Cells before and after uranium sorption were investigate by FTIR spectroscopy → Amino and carboxyl groups were important functional groups involved in uranium binding → The sorption equilibrium date of raw and chemically modified biomass fitted well with Langmuir and Freundlich models

Biosorption of uranium by chemically modified Rhodotorula glutinis

Energy Technology Data Exchange (ETDEWEB)

Bai Jing, E-mail: baijing@impcas.ac.c [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Yao Huijun [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Fan Fangli; Lin Maosheng [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Zhang Lina; Ding Huajie; Lei Fuan; Wu Xiaolei [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Li, Xiaofei [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Guo Junsheng; Qin Zhi [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

2010-11-15

The present paper reports the biosorption of uranium onto chemically modified yeast cells, Rhodotorula glutinis, in order to study the role played by various functional groups in the cell wall. Esterification of the carboxyl groups and methylation of the amino groups present in the cells were carried out by methanol and formaldehyde treatment, respectively. The uranium sorption capacity increased 31% for the methanol-treated biomass and 11% for the formaldehyde-treated biomass at an initial uranium concentration of 140 mg/L. The enhancement of uranium sorption capacity was investigated by Fourier transform infrared (FTIR) spectroscopy analysis, with amino and carboxyl groups were determined to be the important functional groups involved in uranium binding. The biosorption isotherms of uranium onto the raw and chemically modified biomass were also investigated with varying uranium concentrations. Langmuir and Freundlich models were well able to explain the sorption equilibrium data with satisfactory correlation coefficients higher than 0.9. -- Research highlights: {yields} Uranium biosorption on to chemically modified yeast cells {yields} Cells before and after uranium sorption were investigate by FTIR spectroscopy {yields} Amino and carboxyl groups were important functional groups involved in uranium binding {yields} The sorption equilibrium date of raw and chemically modified biomass fitted well with Langmuir and Freundlich models

Process for continuous production of metallic uranium and uranium alloys

Science.gov (United States)

Hayden, Jr., Howard W.; Horton, James A.; Elliott, Guy R. B.

1995-01-01

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.

Process for continuous production of metallic uranium and uranium alloys

Science.gov (United States)

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

1995-06-06

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.

Mid-crustal uranium and rare metal mineralisation in the Mount Isa Inlier: a genetic model for formation of orogenic uranium deposits

OpenAIRE

McGloin, Matthew

2017-01-01

Uranium mineralisation near Mount Isa in northwest Queensland, Australia, is widespread yet poorly understood. Within this region in the Western Fold Belt, one hundred and ninety uranium-rare metal occurrences are known. This uranium mineralisation is similar to worldwide examples of albitite-hosted or sodium-metasomatic uranium deposits, which host albite-carbonate ore zones enriched in incompatible elements. Various metal sources and ore-forming processes have been sugg...

RECALIBRATION OF H CANYON ONLINE SPECTROPHOTOMETER AT EXTENDED URANIUM CONCENTRATION

International Nuclear Information System (INIS)

Lascola, R

2008-01-01

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 (2σ) for Tanks 15.4 and 17.5 are ∼5% for uranium and ∼25% for nitric acid

Comminution by hydriding-dehydriding process of the U-Zr-Nb alloys stabilized at different phases by aging heat treatment

International Nuclear Information System (INIS)

Cantagalli, Natalia Mattar; Pais, Rafael Witter Dias; Braga, Daniel Martins; Santos, Ana Maria Matildes dos; Ferraz, Wilmar Barbosa

2011-01-01

Powders of the U-Zr-Nb alloys are raw materials for obtaining plate-type dispersion fuel of high density and medium enrichment for research and test reactors as well as small power reactors. U-2.5Zr-7.5Nb and U-3Zr-9Nb (wt%) alloys, initially homogenized at high temperatures, were transformed at different phases by means aging heat treatments, and then comminuted by hydriding-dehydriding process to powder production. The phases transformations were obtained by the homogenization of the U-2.5Zr-7.5Nb and U-3Zr-9Nb alloys at high temperatures (1000 deg C for 1 and 16 h), followed by aging heat treatment at 600 deg C, in times of 0.5 h, 3.0 h and 24h, and subsequently quenched in water to stabilize the desired phase. The comminution process was performed at 200 deg C for different times ranging from 20 minutes to 4 hours. The powders were then characterized by scanning electron microscopy, X-ray diffraction and determination of particle size distribution by means of laser equipment CILAS. One of the main objectives of this study was to verify the influence of the different phases in the characteristics of the obtained powders. It was found that alloys stabilized in gamma phase produced powders with smaller particles sizes than those with cellular structure of the α and γ phases. Regardless of retained phases, the produced powders consist of agglomerates with irregular morphology. (author)

Comminution by hydriding-dehydriding process of the U-Zr-Nb alloys stabilized at different phases by aging heat treatment

Energy Technology Data Exchange (ETDEWEB)

Cantagalli, Natalia Mattar; Pais, Rafael Witter Dias; Braga, Daniel Martins; Santos, Ana Maria Matildes dos; Ferraz, Wilmar Barbosa, E-mail: ferrazw@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG) Belo Horizonte, MG (Brazil)

2011-07-01

Powders of the U-Zr-Nb alloys are raw materials for obtaining plate-type dispersion fuel of high density and medium enrichment for research and test reactors as well as small power reactors. U-2.5Zr-7.5Nb and U-3Zr-9Nb (wt%) alloys, initially homogenized at high temperatures, were transformed at different phases by means aging heat treatments, and then comminuted by hydriding-dehydriding process to powder production. The phases transformations were obtained by the homogenization of the U-2.5Zr-7.5Nb and U-3Zr-9Nb alloys at high temperatures (1000 deg C for 1 and 16 h), followed by aging heat treatment at 600 deg C, in times of 0.5 h, 3.0 h and 24h, and subsequently quenched in water to stabilize the desired phase. The comminution process was performed at 200 deg C for different times ranging from 20 minutes to 4 hours. The powders were then characterized by scanning electron microscopy, X-ray diffraction and determination of particle size distribution by means of laser equipment CILAS. One of the main objectives of this study was to verify the influence of the different phases in the characteristics of the obtained powders. It was found that alloys stabilized in gamma phase produced powders with smaller particles sizes than those with cellular structure of the {alpha} and {gamma} phases. Regardless of retained phases, the produced powders consist of agglomerates with irregular morphology. (author)

Post-mining water treatment. Nanofiltration of uranium-contaminated drainage. Experiments and modeling

Energy Technology Data Exchange (ETDEWEB)

Hoyer, Michael

2017-07-01

Nanofiltration of real uranium-contaminated mine drainage was successfully discussed in experiments and modeling. For the simulation a renowned model was adapted that is capable of describing multi-component solutions. Although the description of synthetic multi-component solutions with a limited number of components was performed before ([Garcia-Aleman2004], [Geraldes2006], [Bandini2003]) the results of this work show that the adapted model is capable of describing the very complex solution. The model developed here is based on: The Donnan-Steric Partitioning Pore Model incorporating Dielectric Exclusion - DSPM and DE ref. [Bowen1997], [Bandini2003], [Bowen2002], [Vezzani2002]. The steric, electric, and dielectric exclusion model - SEDE ref. [Szymczyk2005]. The developed modeling approach is capable of describing multi-component transport, and is based on the pore radius, membrane thickness, and volumetric membrane charge density as physically relevant membrane parameters instead of mere fitting parameters which allows conclusions concerning membrane modification or process design. The experiments involve typical commercially available membranes in combination with a water sample of industrial relevance in the mining sector. Furthermore, it has been shown experimentally that uranium speciation influences its retention. Hence, all experiments consider the speciation of uranium when assessing its charge and size. In the simulation 10 different ionic components have been taken into account. By freely fitting 4 parameters in parallel (pore radius, membrane thickness, membrane charge, relative permittivity of the oriented water layer at the pore wall) an excellent agreement between experiment and simulation was obtained. Moreover, the determined membrane thickness and pore radius is in close agreement with the values obtained by independent membrane characterization using pure water permeability and glucose retention. On the other hand, the fitted and the literature

Post-mining water treatment. Nanofiltration of uranium-contaminated drainage. Experiments and modeling

International Nuclear Information System (INIS)

Hoyer, Michael

2017-01-01

Nanofiltration of real uranium-contaminated mine drainage was successfully discussed in experiments and modeling. For the simulation a renowned model was adapted that is capable of describing multi-component solutions. Although the description of synthetic multi-component solutions with a limited number of components was performed before ([Garcia-Aleman2004], [Geraldes2006], [Bandini2003]) the results of this work show that the adapted model is capable of describing the very complex solution. The model developed here is based on: The Donnan-Steric Partitioning Pore Model incorporating Dielectric Exclusion - DSPM and DE ref. [Bowen1997], [Bandini2003], [Bowen2002], [Vezzani2002]. The steric, electric, and dielectric exclusion model - SEDE ref. [Szymczyk2005]. The developed modeling approach is capable of describing multi-component transport, and is based on the pore radius, membrane thickness, and volumetric membrane charge density as physically relevant membrane parameters instead of mere fitting parameters which allows conclusions concerning membrane modification or process design. The experiments involve typical commercially available membranes in combination with a water sample of industrial relevance in the mining sector. Furthermore, it has been shown experimentally that uranium speciation influences its retention. Hence, all experiments consider the speciation of uranium when assessing its charge and size. In the simulation 10 different ionic components have been taken into account. By freely fitting 4 parameters in parallel (pore radius, membrane thickness, membrane charge, relative permittivity of the oriented water layer at the pore wall) an excellent agreement between experiment and simulation was obtained. Moreover, the determined membrane thickness and pore radius is in close agreement with the values obtained by independent membrane characterization using pure water permeability and glucose retention. On the other hand, the fitted and the literature

Uranium Elemental and Isotopic Constraints on Groundwater Flow Beneath the Nopal I Uranium Deposit, Pena Blanca, Mexico

International Nuclear Information System (INIS)

S.J. Goldstein; M.T. Murrell; A.M. Simmons

2005-01-01

The Nopal I uranium deposit in Chihuahua, Mexico, is an excellent analogue for evaluating the fate of spent fuel, associated actinides, and fission products over long time scales for the proposed Yucca Mountain high-level nuclear waste repository. In 2003, three groundwater wells were drilled directly adjacent to (PB-1) and 50 m on either side of the uranium deposit (PB-2 and PB-3) in order to evaluate uranium-series transport in three dimensions. After drilling, uranium concentrations were elevated in all of the three wells (0.1-18 ppm) due to drilling activities and subsequently decreased to ∼5-20% of initial values over the next several months. The 234 U/ 238 U activity ratios were similar for PB-1 and PB-2 (1.005 to 1.079) but distinct for PB-3 (1.36 to 1.83) over this time period, suggesting limited mixing between groundwater from these wells over these short time and length scales. Regional groundwater wells located up to several km from the deposit also have distinct uranium isotopic characteristics and constrain mixing over larger length and time scales. We model the decreasing uranium concentrations in the newly drilled wells with a simple one-dimensional advection-dispersion model, assuming uranium is introduced as a slug to each of the wells and transported as a conservative tracer. Using this model for our data, the relative uranium concentrations are dependent on both the longitudinal dispersion as well as the mean groundwater flow velocity. These parameters have been found to be correlated in both laboratory and field studies of groundwater velocity and dispersion (Klotz et al., 1980). Using typical relationships between velocity and dispersion for field and laboratory studies along with the relationship observed from our uranium data, both velocity (1-10 n/yr) and dispersion coefficient (1E-5 to 1E-2 cm 2 /s) can be derived from the modeling. As discussed above, these relatively small flow velocities and dispersivities agree with mixing

Uranium ore deposits

International Nuclear Information System (INIS)

Angelelli, Victorio.

1984-01-01

The main uranium deposits and occurrences in the Argentine Republic are described, considering, in principle, their geologic setting, the kind of 'model' of the mineralization and its possible origin, and describing the ore species present in each case. The main uraniferous accumulations of the country include the models of 'sandstong type', veintype and impregnation type. There are also other kinds of accumulations, as in calcrete, etc. The main uranium production has been registered in the provinces of Mendoza, Salta, La Rioja, Chubut, Cordoba and San Luis. In each case, the minerals present are mentioned, having been recognized 37 different species all over the country (M.E.L.) [es

Inhalation hazards to uranium miners

International Nuclear Information System (INIS)

Cross, F.T.

1986-01-01

This project is investigating levels of uranium mine air contaminants, using both large and small experimental animals to model human respiratory system diseases. Lung cancer and deaths by degenerative lung disease have reached epidemic proportions among uranium miners, but the cause-effect relationships for these diseases are based on inadequate epidemiological data. This project identifies uranium mine air agents or combinations of agents (both chemical and radiological), and their exposure levels, that produce respiratory tract lesions, including respiratory epithelial carcinoma, pneumoconiosis, and emphysema. Histopathologic data from serially sacrificed rats are reported for approximately 20- to 640- working-level-month (WLM) radon-daughter exposures delivered at one-tenth the rate of previous exposures. Exposure of male rats to radon daughters and uranium ore dust continues, along with exposure of male and female beagle dogs to uranium ore dust alone

Uranium fission track length distribution modelling for retracing chronothermometrical history of minerals

International Nuclear Information System (INIS)

Rebetez, M.

1987-01-01

Spontaneous fission of uranium 238 isotope contained in certain minerals creates damage zones called latent tracks, that can be etched chemically. The observation of these etched tracks and the measurement of their characteristics using an optical microscope are the basis of several applications in the domain of the earth sciences. First, the determination of their densities permits dating a mineral and establishing uranium mapping of rocks. Second, the measurement of their lengths can be a good source of information for retracing the thermal and tectonic history of the sample. The study of the partial annealing of tracks in apatite appears to be the ideal indicator for the evaluation of petroleum potential of a sedimentary basin. To allow the development of this application, it is necessary to devise a theoretical model of track length distributions. The model which is proposed takes into account the most realistic hypotheses concerning registration, etching and observation of tracks. The characteristics of surface tracks (projected lengths, depths, inclination angles, real lengths) and confined tracks (Track IN Track and Track IN Cleavage) are calculated. Surface tracks and confined tracks are perfectly complementary for chrono-thermometric interpretation of complex geological histories. The method is applied to the case of two samples with different tectonic history, issued from the cretaceous alcalin magmatism from the Pyrenees (Bilbao, Spain). A graphic method of distribution deconvolution is proposed. Finally, the uranium migration, depending on the hydrothermal alteration, is studied on the granite from Auriat (France) [fr

230Th-234U Model-Ages of Some Uranium Standard Reference Materials

Energy Technology Data Exchange (ETDEWEB)

Williams, R W; Gaffney, A M; Kristo, M J; Hutcheon, I D

2009-05-28

The 'age' of a sample of uranium is an important aspect of a nuclear forensic investigation and of the attribution of the material to its source. To the extent that the sample obeys the standard rules of radiochronometry, then the production ages of even very recent material can be determined using the {sup 230}Th-{sup 234}U chronometer. These standard rules may be summarized as (a) the daughter/parent ratio at time=zero must be known, and (b) there has been no daughter/parent fractionation since production. For most samples of uranium, the 'ages' determined using this chronometer are semantically 'model-ages' because (a) some assumption of the initial {sup 230}Th content in the sample is required and (b) closed-system behavior is assumed. The uranium standard reference materials originally prepared and distributed by the former US National Bureau of Standards and now distributed by New Brunswick Laboratory as certified reference materials (NBS SRM = NBL CRM) are good candidates for samples where both rules are met. The U isotopic standards have known purification and production dates, and closed-system behavior in the solid form (U{sub 3}O{sub 8}) may be assumed with confidence. We present here {sup 230}Th-{sup 234}U model-ages for several of these standards, determined by isotope dilution mass spectrometry using a multicollector ICP-MS, and compare these ages with their known production history.

Recovery of uranium from crude uranium tetrafluoride

Energy Technology Data Exchange (ETDEWEB)

Ghosh, S K; Bellary, M P; Keni, V S [Chemical Engineering Division, Bhabha Atomic Research Centre, Mumbai (India)

1994-06-01

An innovative process has been developed for recovery of uranium from crude uranium tetrafluoride cake. The process is based on direct dissolution of uranium tetrafluoride in nitric acid in presence of aluminium hydroxide and use of solvent extraction for removal of fluorides and other bulk impurities to make uranium amenable for refining. It is a simple process requiring minimum process step and has advantage of lesser plant corrosion. This process can be applied for processing of uranium tetrafluoride generated from various sources like uranium by-product during thorium recovery from thorium concentrate, first stage product of uranium recovery from phosphoric acid by OPPA process and off grade uranium tetrafluoride material. The paper describes the details of the process developed and demonstrated on bench and pilot scale and its subsequent modification arising out of bulky solid waste generation. The modified process uses a lower quantity of aluminium hydroxide by allowing a lower dissolution of uranium per cycle and recycles the undissolved material to the next cycle, maintaining the overall recovery at high level. This innovation has reduced the solid waste generated by a factor of four at the cost of a slightly larger dissolution vessel and its increased corrosion rate. (author). 4 refs., 1 fig., 3 tabs.

Recovery of uranium from crude uranium tetrafluoride

International Nuclear Information System (INIS)

Ghosh, S.K.; Bellary, M.P.; Keni, V.S.

1994-01-01

An innovative process has been developed for recovery of uranium from crude uranium tetrafluoride cake. The process is based on direct dissolution of uranium tetrafluoride in nitric acid in presence of aluminium hydroxide and use of solvent extraction for removal of fluorides and other bulk impurities to make uranium amenable for refining. It is a simple process requiring minimum process step and has advantage of lesser plant corrosion. This process can be applied for processing of uranium tetrafluoride generated from various sources like uranium by-product during thorium recovery from thorium concentrate, first stage product of uranium recovery from phosphoric acid by OPPA process and off grade uranium tetrafluoride material. The paper describes the details of the process developed and demonstrated on bench and pilot scale and its subsequent modification arising out of bulky solid waste generation. The modified process uses a lower quantity of aluminium hydroxide by allowing a lower dissolution of uranium per cycle and recycles the undissolved material to the next cycle, maintaining the overall recovery at high level. This innovation has reduced the solid waste generated by a factor of four at the cost of a slightly larger dissolution vessel and its increased corrosion rate. (author)

The solubility of uranium in cementitious near-field chemical conditions

Energy Technology Data Exchange (ETDEWEB)

Baston, G.M.N.; Brownsword, M.; Cross, J.E.; Hobley, J.; Moreton, A.D.; Smith-Briggs, J.L.; Thomason, H.P. [AEA Decommissioning and Waste Management, Harwell (United Kingdom)

1993-05-01

Tetravalent and hexavalent uranium solubilities have been measured in cement-equilibriated water for pH values from 4 to 13. Tetravalent uranium solubilities at pH 12 have been measured by three experimental techniques: oversaturation, undersaturation and by the use of an electrochemical cell which controlled the redox conditions. The experimentally obtained data have been simulated using the thermodynamic equilibrium program HARPHRQ in conjunction with three different sets of thermodynamic data for uranium. In each case, differences were found between the predicted and measured uranium behaviour. For hexavalent uranium at high pH values the model suggested the formation of anionic hydrolysis products which led to the prediction of uranium solubilities significantly higher than those observed. Refinement of the thermodynamic data used in the model enabled the derivation of maximum values for the formation constants of these species under cementitious conditions. Similarly, the experimental data have been used to refine a model of tetravalent uranium solubility under cementitious near-field conditions. (author).

The solubility of uranium in cementitious near-field chemical conditions

International Nuclear Information System (INIS)

Baston, G.M.N.; Brownsword, M.; Cross, J.E.; Hobley, J.; Moreton, A.D.; Smith-Briggs, J.L.; Thomason, H.P.

1993-05-01

Tetravalent and hexavalent uranium solubilities have been measured in cement-equilibriated water for pH values from 4 to 13. Tetravalent uranium solubilities at pH 12 have been measured by three experimental techniques: oversaturation, undersaturation and by the use of an electrochemical cell which controlled the redox conditions. The experimentally obtained data have been simulated using the thermodynamic equilibrium program HARPHRQ in conjunction with three different sets of thermodynamic data for uranium. In each case, differences were found between the predicted and measured uranium behaviour. For hexavalent uranium at high pH values the model suggested the formation of anionic hydrolysis products which led to the prediction of uranium solubilities significantly higher than those observed. Refinement of the thermodynamic data used in the model enabled the derivation of maximum values for the formation constants of these species under cementitious conditions. Similarly, the experimental data have been used to refine a model of tetravalent uranium solubility under cementitious near-field conditions. (author)

Uranium: biokinetics and toxicity

International Nuclear Information System (INIS)

Menetrier, F.; Renaud-Salis, V.; Flury-Herard, A.

2000-01-01

This report was achieved as a part of a collaboration with the Fuel Cycle Direction. Its aim was to give the state of the art about: the behaviour of uranium in the human organism (biokinetics) after ingestion, its toxicity (mainly renal) and the current regulation about its incorporation. Both in the upstream and in the downstream of the fuel cycle, uranium remains, quantitatively, the first element in the cycle which is, at the present time, temporarily disposed or recycled. Such a considerable quantity of uranium sets the problem of its risk on the health. In the long term, the biosphere may be affected and consequently the public may ingest water or food contaminated with uranium. In this way, radiological and chemical toxicity risk may be activated. This report emphasizes: the necessity of confirming some experimental and epidemiological biokinetic data used or not in the ICRP models. Unsolved questions remain about the gastrointestinal absorption according to chemical form (valency state, mixtures...), mass and individual variations (age, disease) further a chronic ingestion of uranium. It is well established that uranium is mainly deposited in the skeleton and the kidney. But the skeleton kinetics following a chronic ingestion and especially in some diseases has to be more elucidated; the necessity of taking into account uranium at first as a chemical toxic, essentially in the kidney and determining the threshold of functional lesion. In this way, it is important to look for some specific markers; the problem of not considering chemical toxicity of uranium in the texts regulating its incorporation

Copper Mountain, Wyoming, intermediate-grade uranium resource assessment project. Final report. National Uranium Resource Evaluation

International Nuclear Information System (INIS)

Madson, M.E.; Ludlam, J.R.; Fukui, L.M.

1982-11-01

Intermediate-grade uranium resources were delineated and estimated for Eocene and Precambrian host rock environments in the 39.64 mi 2 Copper Mountain, Wyoming, assessment area. Geologic reconnaissance and geochemical, geophysical, petrologic, borehole, and structural data were interpreted and used to develop a genetic model for uranium mineralization in these environments. Development of a structural scoring system and application of computer graphics in a high-confidence control area established the basis for estimations of uranium resources in the total assessment area. 8 figures, 5 tables

A metallogenetic model of supergene extraction, releasing and enrichment in the mixed zone for granite-type uranium deposits in south China

International Nuclear Information System (INIS)

Li Minglian.

1986-01-01

The major geological features and their related geological events provide a base for the modelling of granite-type uranium deposits in South China. This paper presents a metallogenetic model to suggest the process of ore fluid circulation. There are two streams of ore fluids moving in the fracture zone: one comes from meteoric water and extracts uranium from wall rocks, flowing from top to bottom which is named uranium-loading fluid; another derives from the depth of the crust flowing from bottom to top and contains reducing matters as H 2 S etc. called uranium-releasing fluid. These two streams of solutions of different genesis, composition and character encountered and mixed at certain depth to precipitate the uranium. During the process the longitudinal circulation of underground thermal water in fracture zone results in the Bernoulli latitudinal circulation of ore fluids, which caused the ore fluids to ceaselessly flow into the minerogenetic location, where mineralization can be formed continuously in a certain period

Standard model for safety analysis report of hexafluoride power plants from natural uranium

International Nuclear Information System (INIS)

1983-01-01

The standard model for safety analysis report for hexafluoride production power plants from natural uranium is presented, showing the presentation form, the nature and the degree of detail, of the minimal information required by the Brazilian Nuclear Energy Commission - CNEN. (E.G.) [pt

Comparison of a semi-analytic and a CFD model uranium combustion to experimental data

International Nuclear Information System (INIS)

Clarksean, R.

1998-01-01

Two numerical models were developed and compared for the analysis of uranium combustion and ignition in a furnace. Both a semi-analytical solution and a computational fluid dynamics (CFD) numerical solution were obtained. Prediction of uranium oxidation rates is important for fuel storage applications, fuel processing, and the development of spent fuel metal waste forms. The semi-analytical model was based on heat transfer correlations, a semi-analytical model of flow over a flat surface, and simple radiative heat transfer from the material surface. The CFD model numerically determined the flowfield over the object of interest, calculated the heat and mass transfer to the material of interest, and calculated the radiative heat exchange of the material with the furnace. The semi-analytical model is much less detailed than the CFD model, but yields reasonable results and assists in understanding the physical process. Short computation times allowed the analyst to study numerous scenarios. The CFD model had significantly longer run times, was found to have some physical limitations that were not easily modified, but was better able to yield details of the heat and mass transfer and flow field once code limitations were overcome

Analytical method of uranium (IV) and uranium (VI) in uranium ores and uranium-bearing rocks

International Nuclear Information System (INIS)

Shen Zhuqin; Zheng Yongfeng; Li Qingzhen; Zhong Miaolan; Gu Dingxiang

1995-11-01

The best conditions for keeping the original valences of uranium during the dissolution and separation procedure of geological samples (especially those micro uranium-bearing rock) were studied. With the exist of high concentration protectants, the sample was decomposed with concentration HF at 40 +- 5 degree C. The U(VI) was dissolved completely and formed stable complex UO 2 F 2 , the U(IV) was precipitated rapidly and carried by carrier. Quantitative separation was carried out immediately with suction. The decomposition of sample and separation of solid/liquid phases was completed within two minutes. After separation, the U(IV) and U(VI) were determined quantitatively with laser fluorescence or voltametry respectively according to the uranium content. The limit of detection for this method is 0.7 μg/g, RSD is 10.5%, the determinate range of uranium is 2 x 10 -6 ∼10 -1 g/g. The uranium contents and their valence state ratio were measured for more than one hundred samples of sand stone and granite, the accuracy and precision of these results are satisfactory for uranium geological research. (12 tabs.; 11 refs.)

Reduction of uranium hexafluoride to uranium tetrafluoride

International Nuclear Information System (INIS)

Chang, I.S.; Do, J.B.; Choi, Y.D.; Park, M.H.; Yun, H.H.; Kim, E.H.; Kim, Y.W.

1982-01-01

The single step continuous reduction of uranium hexafluoride (UF 6 ) to uranium tetrafluoride (UF 4 ) has been investigated. Heat required to initiate and maintain the reaction in the reactor is supplied by the highly exothermic reaction of hydrogen with a small amount of elemental fluorine which is added to the uranium hexafluoride stream. When gases uranium hexafluoride and hydrogen react in a vertical monel pipe reactor, the green product, UF 4 has 2.5g/cc in bulk density and is partly contaminated by incomplete reduction products (UF 5 ,U 2 F 9 ) and the corrosion product, presumably, of monel pipe of the reactor itself, but its assay (93% of UF 4 ) is acceptable for the preparation of uranium metal with magnesium metal. Remaining problems are the handling of uranium hexafluoride, which is easily clogging the flowmeter and gas feeding lines because of extreme sensitivity toward moisture, and a development of gas nozzel for free flow of uranium hexafluoride gas. (Author)

Precise coulometric titration of uranium in a high-purity uranium metal and in uranium compounds

International Nuclear Information System (INIS)

Tanaka, Tatsuhiko; Yoshimori, Takayoshi

1975-01-01

Uranium in uranyl nitrate, uranium trioxide and a high-purity uranium metal was assayed by the coulometric titration with biamperometric end-point detection. Uranium (VI) was reduced to uranium (IV) by solid bismuth amalgam in 5M sulfuric acid solution. The reduced uranium was reoxidized to uranium (VI) with a large excess of ferric ion at a room temperature, and the ferrous ion produced was titrated with the electrogenerated manganese(III) fluoride. In the analyses of uranium nitrate and uranium trioxide, the results were precise enough when the error from uncertainty in water content in the samples was considered. The standard sample of pure uranium metal (JAERI-U4) was assayed by the proposed method. The sample was cut into small chips of about 0.2g. Oxides on the metal surface were removed by the procedure shown by National Bureau of Standards just before weighing. The mean assay value of eleven determinations corrected for 3ppm of iron was (99.998+-0.012) % (the 95% confidence interval for the mean), with a standard deviation of 0.018%. The proposed coulometric method is simple and permits accurate and precise determination of uranium which is matrix constituent in a sample. (auth.)

31 CFR 540.317 - Uranium feed; natural uranium feed.

Science.gov (United States)

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Uranium feed; natural uranium feed... (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.317 Uranium feed; natural uranium feed. The...

Uranium exploration

International Nuclear Information System (INIS)

De Voto, R.H.

1984-01-01

This paper is a review of the methodology and technology that are currently being used in varying degrees in uranium exploration activities worldwide. Since uranium is ubiquitous and occurs in trace amounts (0.2 to 5 ppm) in virtually all rocks of the crust of the earth, exploration for uranium is essentially the search of geologic environments in which geologic processes have produced unusual concentrations of uranium. Since the level of concentration of uranium of economic interest is dependent on the present and future price of uranium, it is appropriate here to review briefly the economic realities of uranium-fueled power generation. (author)

Uranium

International Nuclear Information System (INIS)

1982-01-01

The development, prospecting, research, processing and marketing of South Africa's uranium industry and the national policies surrounding this industry form the headlines of this work. The geology of South Africa's uranium occurences and their positions, the processes used in the extraction of South Africa's uranium and the utilisation of uranium for power production as represented by the Koeberg nuclear power station near Cape Town are included in this publication

Assessment of the bioavailability and depuration of uranium, cesium and thorium in snails (Cantareus aspersus) using kinetics models

Energy Technology Data Exchange (ETDEWEB)

Pauget, B., E-mail: benjamin.pauget@tesora.fr [Tésora, Le Visium, 22 Av. Aristide Briand, 94110 Arcueil (France); Andra, R& D Division, Centre de Meuse/Haute-Marne, RD 960, 55290 Bure (France); University of Bourgogne Franche-Comté, Department Chrono-Environnement, UMR UFC/CNRS 6249, 16 Route de Gray, 25030 Besançon Cedex (France); Villeneuve, A.; Redon, P.O. [Tésora, Le Visium, 22 Av. Aristide Briand, 94110 Arcueil (France); Cuvier, A. [ECOLAB, Université de Toulouse, CNRS, INPT, UPS, Toulouse (France); IRSN/PRP-ENV/SESURE/Laboratoire d’études radioécologiques en milieu continental et marin, BP 1, 13108 Saint-Paul-lès-Durance Cedex (France); Vaufleury, A. de [University of Bourgogne Franche-Comté, Department Chrono-Environnement, UMR UFC/CNRS 6249, 16 Route de Gray, 25030 Besançon Cedex (France)

2017-08-05

Highlights: • Kinetic studies allow to take into account the dynamic mechanisms of bioavailability. • An absence of Cs and Th accumulation is evidenced showing their low bioavailability. • The uranium accumulation is not only a function of the soil contamination. - Abstract: Uranium ore waste has led to soil contamination that may affect both environmental and soil health. To analyze the risk of metal transfer, metal bioavailability must be estimated by measuring biological parameters. Kinetic studies allow taking into account the dynamic mechanisms of bioavailability, as well as the steady state concentration in organisms necessary to take into account for relevant risk assessment. In this way, this work aims to model the snail accumulation and excretion kinetics of uranium (U), cesium (Cs) and thorium (Th). Results indicate an absence of Cs and Th accumulation showing the low bioavailability of these two elements and a strong uranium accumulation in snails related to the levels of soil contamination. During the depuration phase, most of the uranium ingested was excreted by the snails. After removing the source of uranium by soil remediation, continued snails excretion of accumulated uranium would lead to the return of their initial internal concentration, thus the potential trophic transfer of this hazardous element would stop.

Assessment of the bioavailability and depuration of uranium, cesium and thorium in snails (Cantareus aspersus) using kinetics models

International Nuclear Information System (INIS)

Pauget, B.; Villeneuve, A.; Redon, P.O.; Cuvier, A.; Vaufleury, A. de

2017-01-01

Highlights: • Kinetic studies allow to take into account the dynamic mechanisms of bioavailability. • An absence of Cs and Th accumulation is evidenced showing their low bioavailability. • The uranium accumulation is not only a function of the soil contamination. - Abstract: Uranium ore waste has led to soil contamination that may affect both environmental and soil health. To analyze the risk of metal transfer, metal bioavailability must be estimated by measuring biological parameters. Kinetic studies allow taking into account the dynamic mechanisms of bioavailability, as well as the steady state concentration in organisms necessary to take into account for relevant risk assessment. In this way, this work aims to model the snail accumulation and excretion kinetics of uranium (U), cesium (Cs) and thorium (Th). Results indicate an absence of Cs and Th accumulation showing the low bioavailability of these two elements and a strong uranium accumulation in snails related to the levels of soil contamination. During the depuration phase, most of the uranium ingested was excreted by the snails. After removing the source of uranium by soil remediation, continued snails excretion of accumulated uranium would lead to the return of their initial internal concentration, thus the potential trophic transfer of this hazardous element would stop.

Magnetic study of solid uranium-fluorine complexes; Contribution a l'etude magnetique de composes fluores solides de l'uranium

Energy Technology Data Exchange (ETDEWEB)

Dianoux, A J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1969-06-01

A study of the magnetic susceptibility of uranium V fluorine complexes and of the magnetic resonance of fluorine atoms in uranium VI fluorine complexes has made it possible to put forward a structural model for these compounds for which it is impossible, because of the lack of suitable single crystals for X-ray diffraction work, to deduce the exact position of the fluorine atoms. It is shown that it is difficult to interpret the paramagnetism of uranium fluorides, because the uranium ions are in low-symmetry sites. A theoretical study of the magnetism of the U{sup V} ion in complex fluorides of the type M{sub 3}UF{sub 8} (M = NH{sub 4}, Na, Rb, Cs) leads to an interpretation based on a trigonal deformation of the eight fluorine atom structure surrounding the uranium atom. By applying a Hamiltonian spin formalism and making a systematic use of group theory, it is possible to present the susceptibility calculations very concisely. Study of the resonance and of the relaxation of the fluorine atoms in powdered uranium VI complex fluorides suggests a structural model in the case of NaUF{sub 7}. It is shown that the shape of the magnetic resonance absorption lines is strongly affected by the presence of large anisotropic chemical shifts. In the model proposed here, six fluorine atoms are linked to the uranium, atom by strongly covalent bonds in a deformed UF{sub 6} octahedral structure; the seventh fluorine atom remains ionic. The occurrence of a rotational movement of the octahedron is confirmed by a study of the longitudinal relaxation of the fluorine atoms, the activation energy being 0.46 eV. (author) [French] L'etude de la susceptibilite magnetique de complexes fluores d'uranium V et la resonance magnetique des fluors dans des complexes fluores d'uranium VI permettent de proposer un modele structural pour ces composes, ou la diffraction des rayons X, en l'absence de monocristaux convenables, est incapable de preciser la position des atomes de fluor. Nous montrons

A double-layer structure model of uranium-bearing horizon in inland basins of medium to big size, North-west China, and its significance in metallogenic potential assessment

International Nuclear Information System (INIS)

Wang Zhilong.

1985-01-01

This paper presents a double-layer structure model of uranium-bearing horizon, i.e. uranium-bearing horizon = source rock (arkose red beds) + uranium trap (grey beds favourable to uranium precipitation) in inland basins of medium to big size, North-west China. The mechanism of its formation is: during diagenetic-epigenetic processes resulted in arkose red bed formation, feldspar was hydromicatized, feldspar and quartz were replaced by authigenic hematite, goethite and hydrogoethite and became red. In such oxidation process, part of uranium in detritus of silicates such as feldspar, quartz etc. was mobilized and released, but the released uranium can not be precipitated because of the oxidation environment, and it can be diffused during diagenetic dehydration and then precipitated in nearby grey beds with low Eh together with uranium-bearing 'stagnant water' fixed in pores, forming economic uranium concentration. It is evident that uranium deposit could not be formed owing to uranium dispersion in the case of absence of certain pervious grey beds rich in reductants, although arkose red beds could provide sufficient uranium source. Therefore, only the two conditions existed simultaneously, could the uranium-bearing horizons be formed. The significance of the model for uranium prospecting are as follows: 1. Uranium source range is much expanded concerning uranium prospecting in sandstone. Except the source in basement of the basin and its margins, we must also pay attention to the overlying red beds, especially the arkose red beds in inland basin of medium to big size. 2. For the potential assessment of basin and the selection of potential area, the model is an important prospecting criterion. 3. If we apply the main criterion uranium-bearing horizon-arkose red beds well, the buried ore bodies can be found provided that arkose red beds were regarded as a significant criterion of uranium-bearing horizon

Inhalation hazards to uranium miners

International Nuclear Information System (INIS)

Cross, F.T.

1985-01-01

This project is investigating levels of uranium mine air contaminants, using both large and small experimental animals to model human respiratory system disease. Lung cancer and deaths by degenerative lung disease have reached epidemic proportions among uranium miners, but the cause-effect relationships for these diseases are based on inadequate epidemiological data. This project identifies agents or combinations of agents (both chemical and radiological), and their exposure levels, that produce respiratory tract lesions, including respiratory epithelial carcinoma, pneumoconiosis, and emphysema. Histopathologic data from rats are shown for approximately 300- to 10,000-working-level-month (WLM) radon-daughter exposures. Exposure of male rats to radon daughters and uranium ore dust continues, along with exposure of male and female beagle dogs to uranium ore dust alone. 4 tables

Uranium conversion; Urankonvertering

Energy Technology Data Exchange (ETDEWEB)

Oliver, Lena; Peterson, Jenny; Wilhelmsen, Katarina [Swedish Defence Research Agency (FOI), Stockholm (Sweden)

2006-03-15

FOI, has performed a study on uranium conversion processes that are of importance in the production of different uranium compounds in the nuclear industry. The same conversion processes are of interest both when production of nuclear fuel and production of fissile material for nuclear weapons are considered. Countries that have nuclear weapons ambitions, with the intention to produce highly enriched uranium for weapons purposes, need some degree of uranium conversion capability depending on the uranium feed material available. This report describes the processes that are needed from uranium mining and milling to the different conversion processes for converting uranium ore concentrate to uranium hexafluoride. Uranium hexafluoride is the uranium compound used in most enrichment facilities. The processes needed to produce uranium dioxide for use in nuclear fuel and the processes needed to convert different uranium compounds to uranium metal - the form of uranium that is used in a nuclear weapon - are also presented. The production of uranium ore concentrate from uranium ore is included since uranium ore concentrate is the feed material required for a uranium conversion facility. Both the chemistry and principles or the different uranium conversion processes and the equipment needed in the processes are described. Since most of the equipment that is used in a uranium conversion facility is similar to that used in conventional chemical industry, it is difficult to determine if certain equipment is considered for uranium conversion or not. However, the chemical conversion processes where UF{sub 6} and UF{sub 4} are present require equipment that is made of corrosion resistant material.

Nuclear energy in Europe: uranium flow modeling and fuel cycle scenario trade-offs from a sustainability perspective.

Science.gov (United States)

Tendall, Danielle M; Binder, Claudia R

2011-03-15

The European nuclear fuel cycle (covering the EU-27, Switzerland and Ukraine) was modeled using material flow analysis (MFA).The analysis was based on publicly available data from nuclear energy agencies and industries, national trade offices, and nongovernmental organizations. Military uranium was not considered due to lack of accessible data. Nuclear fuel cycle scenarios varying spent fuel reprocessing, depleted uranium re-enrichment, enrichment assays, and use of fast neutron reactors, were established. They were then assessed according to environmental, economic and social criteria such as resource depletion, waste production, chemical and radiation emissions, costs, and proliferation risks. The most preferable scenario in the short term is a combination of reduced tails assay and enrichment grade, allowing a 17.9% reduction of uranium demand without significantly increasing environmental, economic, or social risks. In the long term, fast reactors could theoretically achieve a 99.4% decrease in uranium demand and nuclear waste production. However, this involves important costs and proliferation risks. Increasing material efficiency is not systematically correlated with the reduction of other risks. This suggests that an overall optimization of the nuclear fuel cycle is difficult to obtain. Therefore, criteria must be weighted according to stakeholder interests in order to determine the most sustainable solution. This paper models the flows of uranium and associated materials in Europe, and provides a decision support tool for identifying the trade-offs of the alternative nuclear fuel cycles considered.

Uranium Elemental and Isotopic Constraints on Groundwater Flow Beneath the Nopal I Uranium Deposit, Pena Blanca, Mexico

Energy Technology Data Exchange (ETDEWEB)

S.J. Goldstein; M.T. Murrell; A.M. Simmons

2005-07-11

The Nopal I uranium deposit in Chihuahua, Mexico, is an excellent analogue for evaluating the fate of spent fuel, associated actinides, and fission products over long time scales for the proposed Yucca Mountain high-level nuclear waste repository. In 2003, three groundwater wells were drilled directly adjacent to (PB-1) and 50 m on either side of the uranium deposit (PB-2 and PB-3) in order to evaluate uranium-series transport in three dimensions. After drilling, uranium concentrations were elevated in all of the three wells (0.1-18 ppm) due to drilling activities and subsequently decreased to {approx}5-20% of initial values over the next several months. The {sup 234}U/{sup 238}U activity ratios were similar for PB-1 and PB-2 (1.005 to 1.079) but distinct for PB-3 (1.36 to 1.83) over this time period, suggesting limited mixing between groundwater from these wells over these short time and length scales. Regional groundwater wells located up to several km from the deposit also have distinct uranium isotopic characteristics and constrain mixing over larger length and time scales. We model the decreasing uranium concentrations in the newly drilled wells with a simple one-dimensional advection-dispersion model, assuming uranium is introduced as a slug to each of the wells and transported as a conservative tracer. Using this model for our data, the relative uranium concentrations are dependent on both the longitudinal dispersion as well as the mean groundwater flow velocity. These parameters have been found to be correlated in both laboratory and field studies of groundwater velocity and dispersion (Klotz et al., 1980). Using typical relationships between velocity and dispersion for field and laboratory studies along with the relationship observed from our uranium data, both velocity (1-10 n/yr) and dispersion coefficient (1E-5 to 1E-2 cm{sup 2}/s) can be derived from the modeling. As discussed above, these relatively small flow velocities and dispersivities agree with

Strategy of uranium exploration in Indonesia facing uranium price decreacing trend

International Nuclear Information System (INIS)

Karyono, H.S.

1996-01-01

Uranium oversupply in the last decade has caused uranium price decline and given bad impact to uranium exploration activities all over the world. Such an impact also inclusively affected Nuclear Minerals Development Centre (NMDC). As a consequence, the Centre has to reassess its strategies in order survive. This paper introduces the use of the Strategic Management Process Model to formulate new strategies through strategic planning, implementation, and control. two critical environmental factors i.e, national and international, that directly affect NMDC's activities, are discussed. In addition, strengths, weakness, opportunities, and threat's(SWOT) analysis are utilized to assess and formulate NMDC's strategic obyectives. Finally, three new organization strategic, including program's to scope and obyectives, organization structure and performance improvement, and international U market monitoring and review, are offered. (author). 8 refs; 6 figs

Investigation of uranium (VI) adsorption by polypyrrole

Energy Technology Data Exchange (ETDEWEB)

Abdi, S. [Faculty of Chemical, Petroleum and Gas Engineering, Semnan University, Semnan 35195-363 (Iran, Islamic Republic of); Nasiri, M., E-mail: mnasiri@semnan.ac.ir [Faculty of Chemical, Petroleum and Gas Engineering, Semnan University, Semnan 35195-363 (Iran, Islamic Republic of); Mesbahi, A. [Faculty of Chemical, Petroleum and Gas Engineering, Semnan University, Semnan 35195-363 (Iran, Islamic Republic of); Khani, M.H. [Nuclear Fuel Cycle Research School, Nuclear Science and Technology Research Institute, Tehran, 14395-836 (Iran, Islamic Republic of)

2017-06-15

Highlights: • The adsorbent (polypyrrole) was synthesized by a chemical method using PEG, DBSNa and CTAB as the surfactant. • The solution pH was one of the most important parameters affecting the adsorption of uranium. • The CTAB provided higher removal percentage compared with the other surfactants. • The maximum adsorption capacity obtained from Langmuir isotherm was 87.72 mg/g. • The pseudo second-order model fitted well with the adsorption kinetic of polypyrrole to uranium. - Abstract: The purpose of this study was to investigate the adsorption of uranium (VI) ions on the polypyrrole adsorbent. Polypyrrole was synthesized by a chemical method using polyethylene glycol, sodium dodecylbenzenesulfonate, and cetyltrimethylammonium bromide as the surfactant and iron (III) chloride as an oxidant in the aqueous solution. The effect of various surfactants on the synthesized polymers and their performance as the uranium adsorbent were investigated. Adsorbent properties were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) techniques. The effect of different parameters such as pH, contact time, initial metal ion concentrations, adsorbent dose, and the temperature was investigated in the batch system for uranium adsorption process. It has been illustrated that the adsorption equilibrium time is 7 min. The results showed that the Freundlich model had the best agreement and the maximum adsorption capacity of polypyrrole for uranium (VI) was determined 87.72 mg/g from Langmuir isotherm. In addition, the mentioned adsorption process was fast and the kinetic data were fitted to the Pseudo first and second order models. The adsorption kinetic data followed the pseudo-second-order kinetic model. Moreover, the thermodynamic parameters ΔG{sup 0}, ΔH{sup 0} and ΔS{sup 0} showed that the uranium adsorption process by polypyrrole was endothermic and spontaneous.

Uranium

International Nuclear Information System (INIS)

Mackay, G.A.

1978-01-01

The author discusses the contribution made by various energy sources in the production of electricity. Estimates are made of the future nuclear contribution, the future demand for uranium and future sales of Australian uranium. Nuclear power growth in the United States, Japan and Western Europe is discussed. The present status of the six major Australian uranium deposits (Ranger, Jabiluka, Nabarlek, Koongarra, Yeelerrie and Beverley) is given. Australian legislation relevant to the uranium mining industry is also outlined

Model for the behaviour of thorium and uranium fuels at pelletization

International Nuclear Information System (INIS)

Ferreira Neto, Ricardo Alberto

2000-11-01

In this work, a model for the behaviour of thorium-uranium-mixed oxide microspheres in the pelletizing process is presented. This model was developed in a program whose objective was to demonstrate the viability of producing fissile material through the utilization of thorium in pressurized water reactors. This is important because it allows the saving of the strategic uranium reserves, and makes it possible the nuclear utilization of the large brazilian thorium reserves. The objective was to develop a model for optimizing physical properties of the microspheres, such as density, fracture strength and specific surface, so as to produce fuel pellets with microstructure, density, open porosity and impurity content, in accordance with the fuel specification. And, therefore, to adjust the sol-gel processing parameters in order to obtain these properties, and produce pellets with an optimized microstructure, adequate to a stable behaviour under irradiation. The model made it clear that to achieve this objective, it is necessary to produce microspheres with density and specific surface as small as possible. By changing the sol-gel processing parameters, microspheres with the desired properties were produced, and the model was experimentally verified by manufacturing fuel pellets with optimized microstructures, density, open porosity and impurity content, meeting the specifications for this new nuclear fuel for pressurized water reactors. Furthermore it was possible to obtain mathematical expressions that enables to calculate from the microspheres properties and the utilized compaction pressure, the sinter density that will be obtained in the sintered pellet and the necessary compaction pressure to reach the sintered density specified for the fuel. (author)

Czechoslovak uranium

International Nuclear Information System (INIS)

Pluskal, O.

1992-01-01

Data and knowledge related to the prospecting, mining, processing and export of uranium ores in Czechoslovakia are presented. In the years between 1945 and January 1, 1991, 98,461.1 t of uranium were extracted. In the period 1965-1990 the uranium industry was subsidized from the state budget to a total of 38.5 billion CSK. The subsidies were put into extraction, investments and geologic prospecting; the latter was at first, ie. till 1960 financed by the former USSR, later on the two parties shared costs on a 1:1 basis. Since 1981 the prospecting has been entirely financed from the Czechoslovak state budget. On Czechoslovak territory uranium has been extracted from deposits which may be classified as vein-type deposits, deposits in uranium-bearing sandstones and deposits connected with weathering processes. The future of mining, however, is almost exclusively being connected with deposits in uranium-bearing sandstones. A brief description and characteristic is given of all uranium deposits on Czechoslovak territory, and the organization of uranium mining in Czechoslovakia is described as is the approach used in the world to evaluate uranium deposits; uranium prices and actual resources are also given. (Z.S.) 3 figs

Maximum permissible concentrations of uranium in air

CERN Document Server

Adams, N

1973-01-01

The retention of uranium by bone and kidney has been re-evaluated taking account of recently published data for a man who had been occupationally exposed to natural uranium aerosols and for adults who had ingested uranium at the normal dietary levels. For life-time occupational exposure to uranium aerosols the new retention functions yield a greater retention in bone and a smaller retention in kidney than the earlier ones, which were based on acute intakes of uranium by terminal patients. Hence bone replaces kidney as the critical organ. The (MPC) sub a for uranium 238 on radiological considerations using the current (1959) ICRP lung model for the new retention functions is slightly smaller than for earlier functions but the (MPC) sub a determined by chemical toxicity remains the most restrictive.

Uranium in Niger; L'uranium au Niger

Energy Technology Data Exchange (ETDEWEB)

Gabelmann, E

1978-03-15

This document presents government policy in the enhancement of uranium resources, existing mining companies and their productions, exploitation projects and economical outcome related to the uranium mining and auxiliary activities. [French] Le document presente la politique de l'Etat dans le cadre de la mise en valeur des ressources d'uranium, les societes minieres existantes et leurs productions, les projets d'exploitation d'uranium et les retombees economiques liees aux activites uraniferes et connexes.

Preliminary discussion on deep-sourced uranium metallogenesis and deep prospecting

International Nuclear Information System (INIS)

Huang Shijie

2006-01-01

Prospecting for hydrothermal type uranium deposits should be aimed at medium-to large-sized deposits, and be guided by mantle-sourced, superimposed, deep-sourced metallogenic theory and the establishment of a multifactor, composite, deep-sourced metallogenic model. The author suggests that hydrothermal uranium deposits may be classified into three genetic types, i.e. hydrothermal circulation concentration, postmagmatic hydrothermal and mantle fluid concentration. These types of uranium deposits are characterized by their own metallogenic features and are concentrated in the same mineralization-concentrated area forming a metallogenic series. Large-sized uranium ore fields and rich-large uranium deposits are usually closely associated with mantle-sourced metallogenesis and the formation of such uranium ore fields and deposits is characterized by specific and unique regional geologic environments. Recognition criteria of mantle-sourced metallogenesis are preliminarily proposed in the paper. It is pointed out that prospecting in the future should follow the metallogenic model proper for the specific genetic type, and the establishment of operable prospecting model to realize the model-guided prospecting. (authors)

Modeling the migration of radioactive contaminants in groundwater of in situ leaching uranium mine

International Nuclear Information System (INIS)

Li Chunguang; Tai Kaixuan

2011-01-01

The radioactive contamination of groundwater from in situ leaching (ISL) of uranium mining is a widespread environmental problem. This paper analyzed the monitor results of groundwater contaminations for a in situ leaching uranium mine. A dynamic model of contaminants transport in groundwater in ISL well field was established. The processes and mechanisms of contaminant transport in groundwater were simulated numerically for a ISL well field. A small quantity of U and SO 4 2- migrate to outside of well field during ISL production stage. But the migration velocity and distance of contaminations is small, and the concentration is low. Contaminants migrate as anomalistic tooth-shape. The migration trend of U and SO 4 2- is consistent. Numerical modeling can provide an effective approach to analyse the transport mechanism, and forecast and control the migration of contaminants in groundwater in ISL well field. (authors)

Uranium(VI) retention on quartz and kaolinite. Experiments and modelling

International Nuclear Information System (INIS)

Mignot, G.

2001-01-01

The behaviour of uranium in the geosphere is an important issue for safety performance assessment of nuclear waste repositories, or in the context of contaminated sites due to mining activity related to nuclear field. Under aerobic conditions, the fate of uranium is mainly governed by the ability of minerals to sorb U(VI) aqueous species. Hence, a thorough understanding of U(VI) sorption processes on minerals is required to provide a valuable prediction of U(VI) migration in the environment. In this study, we performed sorption/desorption experiments of U(VI) on quartz and kaolinite, for systems favouring the formation in solution (i) of UO 2 2+ and monomeric hydrolysis products or (ii) of di-/tri-meric uranyl aqueous species, and / or U(VI)-colloids or UO 2 (OH) 2 precipitates, or (iii) of uranyl-carbonate complexes. Particular attention was paid to determine the surface characteristics of the solids and their modification due to dissolution/precipitation processes during experiments. A double layer surface complexation model was applied to our experimental data in order to derive surface complexation equilibria and intrinsic constants which allow a valuable description of U(VI) retention over a wide range of pH, ionic strength, initial concentration of uranium [0.1-10μM] and solid - solution equilibration time. U(VI) sorption on quartz was successfully modeled by using two sets of adsorption equilibria, assuming (i) the formation of the surface complexes SiOUO 2 + , SiOUO 2 OH and SiO(UO 2 ) 3 (OH) 5 , or (ii) the formation of the mono-dentate complex SiO(UO 2 ) 3 (OH) 5 and of the bidentate complex (SiO) 2 UO 2 . Assumptions on the density of each type of surface sites of kaolinite and on their acid-base properties were made from potentiometric titrations of kaolinite suspensions. We proposed on such a basis a set of surface complexation equilibria which accounts for U(VI) uptake on kaolinite over a wide range of chemical conditions, with aluminol edge sites as

The new uranium mining boom. Challenge and lessons learned

International Nuclear Information System (INIS)

Merkel, Broder; Schipek, Mandy

2011-01-01

The book presents the results from the Uranium Mining and Hydrogeology Conference (UMH VI) held in September 2011, in Freiberg, Germany. The following subjects are dealt with in depth: uranium mining, phosphate mining and uranium recovery. Cleaning up technologies for water and soil are also discussed at length. Analystics and sensors for uranium and radon and modelling round up this comprehensive volume. (orig.)

Uranium ores

International Nuclear Information System (INIS)

Poty, B.; Roux, J.

1998-01-01

The processing of uranium ores for uranium extraction and concentration is not much different than the processing of other metallic ores. However, thanks to its radioactive property, the prospecting of uranium ores can be performed using geophysical methods. Surface and sub-surface detection methods are a combination of radioactive measurement methods (radium, radon etc..) and classical mining and petroleum prospecting methods. Worldwide uranium prospecting has been more or less active during the last 50 years, but the rise of raw material and energy prices between 1970 and 1980 has incited several countries to develop their nuclear industry in order to diversify their resources and improve their energy independence. The result is a considerable increase of nuclear fuels demand between 1980 and 1990. This paper describes successively: the uranium prospecting methods (direct, indirect and methodology), the uranium deposits (economical definition, uranium ores, and deposits), the exploitation of uranium ores (use of radioactivity, radioprotection, effluents), the worldwide uranium resources (definition of the different categories and present day state of worldwide resources). (J.S.)

Enhanced Uranium Immobilization and Reduction by Geobacter sulfurreducens Biofilms

Science.gov (United States)

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

2014-01-01

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

Uranium ore deposits: geology and processing implications

International Nuclear Information System (INIS)

Belyk, C.L.

2010-01-01

There are fifteen accepted types of uranium ore deposits and at least forty subtypes readily identified around the world. Each deposit type has a unique set of geological characteristics which may also result in unique processing implications. Primary uranium production in the past decade has predominantly come from only a few of these deposit types including: unconformity, sandstone, calcrete, intrusive, breccia complex and volcanic ones. Processing implications can vary widely between and within the different geological models. Some key characteristics of uranium deposits that may have processing implications include: ore grade, uranium and gangue mineralogy, ore hardness, porosity, uranium mineral morphology and carbon content. Processing difficulties may occur as a result of one or more of these characteristics. In order to meet future uranium demand, it is imperative that innovative processing approaches and new technological advances be developed in order that many of the marginally economic traditional and uneconomic non-traditional uranium ore deposits can be exploited. (author)

Sensitivity analysis of uranium solubility under strongly oxidizing conditions

International Nuclear Information System (INIS)

Liu, L.; Neretnieks, I.

1999-01-01

To evaluate the effect of geochemical conditions in the repository on the solubility of uranium under strongly oxidizing conditions, a mathematical model has been developed to determine the solubility, by utilizing a set of nonlinear algebraic equations to describe the chemical equilibria in the groundwater environment. The model takes into account the predominant precipitation-dissolution reactions, hydrolysis reactions and complexation reactions that may occur under strongly oxidizing conditions. The model also includes the solubility-limiting solids induced by the presence of carbonate, phosphate, silicate, calcium, and sodium in the groundwater. The thermodynamic equilibrium constants used in the solubility calculations are essentially taken from the NEA Thermochemical Data Base of Uranium, with some modification and some uranium minerals added, such as soddyite, rutherfordite, uranophane, uranyl orthophosphate, and becquerelite. By applying this model, the sensitivities of uranium solubility to variations in the concentrations of various groundwater component species are systematically investigated. The results show that the total analytical concentrations of carbonate, phosphate, silicate, and calcium in deep groundwater play the most important role in determining the solubility of uranium under strongly oxidizing conditions

Uranium logging in earth formations

International Nuclear Information System (INIS)

Givens, W.W.

1979-01-01

A technique is provided for assaying the formations surrounding a borehole for uranium. A borehole logging tool cyclically irradiates the formations with neutrons and responds to neutron fluxes produced during the period of time that prompt neutrons are being produced by the neutron fission of uranium in the formations. A borehole calibration tool employs a steady-state (continuous output) neutron source, firstly, to produce a response to neutron fluxes in models having known concentrations of uranium and, secondly, to to produce a response to neutron fluxes in the formations surrounding the borehole. The neutron flux responses of the borehole calibration tool in both the model and the formations surrounding the borehole are utilized to correct the neutron flux response of the borehole logging tool for the effects of epithermal/thermal neutron moderation, scattering, and absorption within the borehole itself

Recovery of uranium resources from sea water

International Nuclear Information System (INIS)

Kurushima, Morihiro

1980-01-01

After the oil crisis in 1973, the development of atomic energy has become important as substitute energy, and the stable acquisition of uranium resources is indispensable, in order to promote smoothly the use of atomic energy. The Ministry of International Trade and Industry has engaged actively in the project ''The survey on the technical development of the system for recovering uranium and others from sea water'' since 1974. 80% of the uranium resources in the world is distributed in USA, Canada, South Africa, Australia and Niger, and in near future, the price of uranium ores may be raised. Japan must promote powerfully the development of foreign uranium resources, but also it is very important to get domestic uranium by efficiently recovering the uranium dissolved in sea water, the amount of which was estimated at 4 billion tons, and its practical use is expected in 1990s. The uranium concentration in sea water is about 3 g in 1000 t sea water. The processes of separation and recovery are as follows: (1) adsorption of uranium to titanic acid powder adsorbent by bringing sea water in contact with it, (2) dissolving the collected uranium with ammonium carbonate, the desorption agent, (3) concentration of uranium solution by ion exchange method or ion flotation method to 2800 ppm. The outline of the model plant is explained. (Kako, I.)

Development of a Kelp-Type Structure Module in a Coastal Ocean Model to Assess the Hydrodynamic Impact of Seawater Uranium Extraction Technology

Directory of Open Access Journals (Sweden)

Taiping Wang

2014-02-01

Full Text Available With the rapid growth of global energy demand, interest in extracting uranium from seawater for nuclear energy has been renewed. While extracting seawater uranium is not yet commercially viable, it serves as a “backstop” to the conventional uranium resources and provides an essentially unlimited supply of uranium resource. With recent technology advances, extracting uranium from seawater could be economically feasible only when the extraction devices are deployed at a large scale (e.g., several hundred km2. There is concern however that the large scale deployment of adsorbent farms could result in potential impacts to the hydrodynamic flow field in an oceanic setting. In this study, a kelp-type structure module based on the classic momentum sink approach was incorporated into a coastal ocean model to simulate the blockage effect of a farm of passive uranium extraction devices on the flow field. The module was quantitatively validated against laboratory flume experiments for both velocity and turbulence profiles.Model results suggest that the reduction in ambient currents could range from 4% to 10% using adsorbent farm dimensions and mooring densities previously described in the literature and with typical drag coefficients.

Biosorption of uranium by immobilized cells of Rhodotorula glutinis

International Nuclear Information System (INIS)

Jing Bai; Zhan Li; Fangli Fan; Xiaolei Wu; Xiaojie Yin; Longlong Tian; Zhi Qin; Junsheng Guo

2014-01-01

Biosorption of uranium ions from diluted solution (≤40 mg L -1 ) onto immobilized cells of Rhodotorula glutinis was investigated in a batch system. Equilibrium, kinetic and thermodynamic studies were conducted by considering the effect of initial uranium concentration, contact time and temperature. Non-linear forms of Langmuir, Freundlich and Sips isotherm models were used to fit the equilibrium data, Sips model was designated as the best one. Kinetic data were simulated by non-linear pseudo-first-order, pseudo-second-order and intra-particle diffusion equations. Pseudo-first-order kinetic equation described the experimental data better than pseudo-second-order equation and intra-particle diffusion equation can fit the kinetic data with two independent curves. Thermodynamic parameters, including ∆H 0, ∆G 0 and ∆S 0, were evaluated, the sorption process was determined to be spontaneous and endothermic. Uranium sorption from pure uranium solutions and uranium pit wastewater by immobilized biomass and blank beads, as well as the regeneration results indicated that immobilized R. glutinis can be use to recovery uranium from uranium pit wastewater. (author)

Evolution of microstructure of U-Mo alloys in as cast and sintered forms

International Nuclear Information System (INIS)

Sinha, V.P.; Hegde, P.V.; Prasad, G.J.; Kamath, H.S.; Dey, G.K.

2009-01-01

Over the years U 3 Si 2 compound dispersed in aluminium matrix has been successfully used as potential Low Enriched Uranium (LEU 235 ) base dispersion fuel in new research and test reactors and also for converting High Enriched Uranium (HEU > 85% U 235 ) cores to LEU in most of the existing research and test reactors. The maximum density achievable with U 3 Si 2 -AI dispersion fuel is around 4.8 g U cm -3 . To achieve a uranium density of 8.0 to 9.0 g U cm -3 in dispersion fuel with aluminium as matrix material, it is required to use γ-stabilized uranium metal powders. At Metallic Fuels Division, R and D efforts are on to develop these high density uranium alloys. Molybdenum plays a crucial role in metastabilising the γ-phase of uranium at room temperature which is very much evident when we see the microstructures of different U-Mo alloys with varying molybdenum concentration as solute atom. The paper describes the role of molybdenum in imparting metastability in U-Mo alloys from their microstructures in as cast and sintered forms. The paper also covers the role of tailored microstructure in U-Mo alloy for the purpose of hydriding and dehydriding treatment to generate alloy powders. (author)

Pengaruh Kandungan Uranium Dalam Umpan Terhadap Efisiensi Pengendapan Uranium

OpenAIRE

Torowati

2010-01-01

PENGARUH KANDUNGAN URANIUM DALAM UMPAN TERHADAP EFISIENSI PENGENDAPAN URANIUM. Setiap aktivitas analisis di Laboratorium Kendali Kualitas, Bidang Bahan Bakar Nuklir selalu dihasilkan limbah radioaktif cair. Limbah radioaktif cair di laboratorium masih mengandung uranium yang cukup besar ± 0,600 g U/l dengan keasamaan yang cukup besar pula. Karena uranium mempunyai nilai ekonomis yang cukup tinggi maka perlu USAha untuk mengambil kembali uranium tersebut. Pada kegiatan ini telah dilak...

Glances on uranium. From uranium in the earth to electric power

International Nuclear Information System (INIS)

Valsardieu, C.

1995-01-01

This book is a technical, scientific and historical analysis of the nuclear fuel cycle from the origin of uranium in the earth and the exploitation of uranium ores to the ultimate storage of radioactive wastes. It comprises 6 chapters dealing with: 1) the different steps of uranium history (discovery, history of uranium chemistry, the radium era, the physicists and the structure of matter, the military uses, the nuclear power, the uranium industry and economics), 2) the uranium in nature (nuclear structure, physical-chemical properties, radioactivity, ores, resources, cycle, deposits), 3) the sidelights on uranium history (mining, prospecting, experience, ore processing, resources, reserves, costs), 4) the uranium in the fuel cycle, energy source and industrial product (fuel cycle, fission, refining, enrichment, fuel processing and reprocessing, nuclear reactors, wastes management), 5) the other energies in competition and the uranium market (other uranium uses, fossil fuels and renewable energies, uranium market), and 6) the future of uranium (forecasting, ecology, economics). (J.S.)

Spectroscopy and chemistry of uranium IV

International Nuclear Information System (INIS)

Folcher, G.; Rigny, P.

1980-06-01

Different fundamental research papers on uranium IV are presented, some were never edited. Molecular spectroscopy was used for identification and structural study of uranium IV in aqueous or organic solutions. The fields studied are: coordination, stereochemistry, electronic structure and chemical properties. For interpretation of results some studies were made with solid compounds or with thorium compounds or thorium complexes. Knowledge of actinides chemistry is improved, uranium and thorium being models for 5 f ions, extractive chemistry is better understood and new applications are possible [fr

Using proteomic data to assess a genome-scale "in silico" model of metal reducing bacteria in the simulation of field-scale uranium bioremediation

Science.gov (United States)

Yabusaki, S.; Fang, Y.; Wilkins, M. J.; Long, P.; Rifle IFRC Science Team

2011-12-01

A series of field experiments in a shallow alluvial aquifer at a former uranium mill tailings site have demonstrated that indigenous bacteria can be stimulated with acetate to catalyze the conversion of hexavalent uranium in a groundwater plume to immobile solid-associated uranium in the +4 oxidation state. While this bioreduction of uranium has been shown to lower groundwater concentrations below actionable standards, a viable remediation methodology will need a mechanistic, predictive and quantitative understanding of the microbially-mediated reactions that catalyze the reduction of uranium in the context of site-specific processes, properties, and conditions. At the Rifle IFRC site, we are investigating the impacts on uranium behavior of pulsed acetate amendment, acetate-oxidizing iron and sulfate reducing bacteria, seasonal water table variation, spatially-variable physical (hydraulic conductivity, porosity) and geochemical (reactive surface area) material properties. The simulation of three-dimensional, variably saturated flow and biogeochemical reactive transport during a uranium bioremediation field experiment includes a genome-scale in silico model of Geobacter sp. to represent the Fe(III) terminal electron accepting process (TEAP). The Geobacter in silico model of cell-scale physiological metabolic pathways is comprised of hundreds of intra-cellular and environmental exchange reactions. One advantage of this approach is that the TEAP reaction stoichiometry and rate are now functions of the metabolic status of the microorganism. The linkage of in silico model reactions to specific Geobacter proteins has enabled the use of groundwater proteomic analyses to assess the accuracy of the model under evolving hydrologic and biogeochemical conditions. In this case, the largest predicted fluxes through in silico model reactions generally correspond to high abundances of proteins linked to those reactions (e.g. the condensation reaction catalyzed by the protein

Uranium prospecting; La prospection de l'uranium

Energy Technology Data Exchange (ETDEWEB)

Roubault, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1955-07-01

This report is an instruction book for uranium prospecting. It appeals to private prospecting. As prospecting is now a scientific and technical research, it cannot be done without preliminary studies. First of all, general prospecting methods are given with a recall of fundamental geologic data and some general principles which are common with all type of prospecting. The peculiarities of uranium prospecting are also presented and in particular the radioactivity property of uranium as well as the special aspect of uranium ores and the aspect of neighbouring ores. In a third part, a description of the different uranium ores is given and separated in two different categories: primary and secondary ores, according to the place of transformation, deep or near the crust surface respectively. In the first category, the primary ores include pitchblende, thorianite and rare uranium oxides as euxenite and fergusonite for example. In the second category, the secondary ores contain autunite and chalcolite for example. An exhaustive presentation of the geiger-Mueller counter is given with the presentation of its different components, its functioning and utilization and its maintenance. The radioactivity interpretation method is showed as well as the elaboration of a topographic map of the measured radioactivity. A brief presentation of other detection methods than geiger-Mueller counters is given: the measurement of fluorescence and a chemical test using the fluorescence properties of uranium salts. Finally, the main characteristics of uranium deposits are discussed. (M.P.)

The model of interaction with the National Operator when doing uranium mining in Kazakhstan

International Nuclear Information System (INIS)

Yermilov, A.; Niyetbayev, M.; Sakharova, Y.

2014-01-01

The report presents a model of organizational and production interaction with the National Operator, NAC Kazatomprom JSC, with regard to uranium mining in Kazakhstan by means of mechanism of joint management of mining, processing and service companies. NAC Kazatomprom JSC is the world's largest producer of uranium, and Uranium One Holding is the largest foreign partner of the National Operator. The mining assets of Uranium One Holdings include the following joint ventures: Betpak Dala LLP (South Inkai and Akdala Mines), Karatau LLP, Akbastau JSC, Kyzylkum LLP and KRC Zarechnoye JSC. It shows that the project management in the form of joint ventures allows for minimization of investment risks in Kazakhstan. The practice of corporate communication with NAC Kazatomprom JSC goes far beyond the “investment– receipt of dividends” scheme when the investment guarantees mean control over the enterprise activities through participation in the meetings of enterprise management bodies. The sustainable model has been developed for the interaction with the National Operator and with state authorities of the Republic of Kazakhstan through or together with the National Operator, whereby various projects have been implemented starting with the joint support of social development of Kazakhstan regions in excess of the minimum amounts established by the government in subsoil use contracts (through Kazatomprom-Demeu LLP, specially established for this purpose) and ending with the implementation of such major projects as the “Atomic Ring” or innovative projects on the construction of alternative energy sources (solar power plant) on sites of joint industrial projects. Effective cooperation with the National operator Kazatomprom allowed to successfully establish and run at the jointly owned mines the program of efficiency improvement which stimulates continuous improvement of current operations and results in considerable cost reduction. The key ideas of the Efficiency

Magnetic study of solid uranium-fluorine complexes; Contribution a l'etude magnetique de composes fluores solides de l'uranium

Energy Technology Data Exchange (ETDEWEB)

Dianoux, A.J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1969-06-01

A study of the magnetic susceptibility of uranium V fluorine complexes and of the magnetic resonance of fluorine atoms in uranium VI fluorine complexes has made it possible to put forward a structural model for these compounds for which it is impossible, because of the lack of suitable single crystals for X-ray diffraction work, to deduce the exact position of the fluorine atoms. It is shown that it is difficult to interpret the paramagnetism of uranium fluorides, because the uranium ions are in low-symmetry sites. A theoretical study of the magnetism of the U{sup V} ion in complex fluorides of the type M{sub 3}UF{sub 8} (M = NH{sub 4}, Na, Rb, Cs) leads to an interpretation based on a trigonal deformation of the eight fluorine atom structure surrounding the uranium atom. By applying a Hamiltonian spin formalism and making a systematic use of group theory, it is possible to present the susceptibility calculations very concisely. Study of the resonance and of the relaxation of the fluorine atoms in powdered uranium VI complex fluorides suggests a structural model in the case of NaUF{sub 7}. It is shown that the shape of the magnetic resonance absorption lines is strongly affected by the presence of large anisotropic chemical shifts. In the model proposed here, six fluorine atoms are linked to the uranium, atom by strongly covalent bonds in a deformed UF{sub 6} octahedral structure; the seventh fluorine atom remains ionic. The occurrence of a rotational movement of the octahedron is confirmed by a study of the longitudinal relaxation of the fluorine atoms, the activation energy being 0.46 eV. (author) [French] L'etude de la susceptibilite magnetique de complexes fluores d'uranium V et la resonance magnetique des fluors dans des complexes fluores d'uranium VI permettent de proposer un modele structural pour ces composes, ou la diffraction des rayons X, en l'absence de monocristaux convenables, est incapable de preciser la position des atomes de

Uranium

International Nuclear Information System (INIS)

Stewart, E.D.J.

1974-01-01

A discussion is given of uranium as an energy source in The Australian economy. Figures and predictions are presented on the world supply-demand position and also figures are given on the added value that can be achieved by the processing of uranium. Conclusions are drawn about Australia's future policy with regard to uranium (R.L.)

Uranium, depleted uranium, biological effects

International Nuclear Information System (INIS)

2001-01-01

Physicists, chemists and biologists at the CEA are developing scientific programs on the properties and uses of ionizing radiation. Since the CEA was created in 1945, a great deal of research has been carried out on the properties of natural, enriched and depleted uranium in cooperation with university laboratories and CNRS. There is a great deal of available data about uranium; thousands of analyses have been published in international reviews over more than 40 years. This presentation on uranium is a very brief summary of all these studies. (author)

A new opportunity for Australian uranium

International Nuclear Information System (INIS)

1994-07-01

This study analyses the outlook for the world uranium industry and includes projections of uranium demand, supply and prices over the next decade and a comparison with other forecasts. The potential increases in Australian output are quantified, under both continuation of the three mine policy and an open mine policy, as well as the potential impact on the world uranium market, using the well known ORANI model of the Australian economy. It is estimated that Australian output could almost double by 2004 if the three mine policy were abolished. 53 refs., 20 tabs., 6 figs

A new opportunity for Australian uranium

Energy Technology Data Exchange (ETDEWEB)

NONE

1994-07-01

This study analyses the outlook for the world uranium industry and includes projections of uranium demand, supply and prices over the next decade and a comparison with other forecasts. The potential increases in Australian output are quantified, under both continuation of the three mine policy and an open mine policy, as well as the potential impact on the world uranium market, using the well known ORANI model of the Australian economy. It is estimated that Australian output could almost double by 2004 if the three mine policy were abolished. 53 refs., 20 tabs., 6 figs.

Development of an On-Line Uranium Enrichment Monitor

International Nuclear Information System (INIS)

Xuesheng, L.; Guorong, L.; Yonggang, Z.; Xueyuan, H. X.-Y.

2015-01-01

An on-line enrichment monitor was developed to measure the enrichment of UF6 flowing through the processing pipes in centrifuge uranium enrichment plant. A NaI(Tl) detector was used to measure the count rates of the 186 keV gamma ray emitted from 235U, and the total quantity of uranium was determined from thermodynamic characteristics of gaseous uranium hexafluoride. The results show that the maximum relative standard deviation is less than 1% when the measurement time is 120 s or more and the pressure is more than 2 kPa in the measurement chamber. There are two working models for the monitor. The monitor works normally in the continuous model, When the gas's pressure in the pipe fluctuates greatly, it can work in the intermittent model, and the measurement result is very well. The background of the monitor can be measured automatically periodically. It can control automatically electromagnetic valves open and close, so as to change the gas's quantity in the chamber. It is a kind of unattended and remote monitor, all of data can be transfer to central control room. It should be effective for nuclear materials accountability verifications and materials balance verification at uranium enrichment plant by using the monitor to monitor Uranium enrichment of gaseous uranium hexafluoride in the output end of cascade continuously. (author)

Uranium complex recycling method of purifying uranium liquors

International Nuclear Information System (INIS)

Elikan, L.; Lyon, W.L.; Sundar, P.S.

1976-01-01

Uranium is separated from contaminating cations in an aqueous liquor containing uranyl ions. The liquor is mixed with sufficient recycled uranium complex to raise the weight ratio of uranium to said cations preferably to at least about three. The liquor is then extracted with at least enough non-interfering, water-immiscible, organic solvent to theoretically extract about all of the uranium in the liquor. The organic solvent contains a reagent which reacts with the uranyl ions to form a complex soluble in the solvent. If the aqueous liquor is acidic, the organic solvent is then scrubbed with water. The organic solvent is stripped with a solution containing at least enough ammonium carbonate to precipitate the uranium complex. A portion of the uranium complex is recycled and the remainder can be collected and calcined to produce U 3 O 8 or UO 2

Introduction of a Uranium tax in Finland

International Nuclear Information System (INIS)

2011-01-01

In Finland, it is possible to create a tax model on uranium that will not compromise the profitability of future power plant investments or decisively reduce climate policy incentives for carbon-free energy production. The rise in energy costs caused by the tax could be compensated by lowering the electricity tax imposed on industry. The estimates above were made by Managing Director Pasi Holm and Professor Markku Ollikainen, who, on 4 February 2011, handed over their report concerning introduction of uranium tax to Minister of Economic Affairs Mauri Pekkarinen. According to the administrators, one can deem nuclear power to include specific grounds for imposing a tax via the fact that storage of used nuclear fuel involves a (infinitesimally small) risk of accidents with irreversible effects, and that, through the EU climate policy, nuclear power companies gain extra profit 'for nothing', i.e. windfall profit. The EU Energy Tax Directive facilitates collection of uranium tax. Uranium tax, imposed as an excise tax, would target the nuclear power plants in operation as well as the Olkiluoto 3 plant, presently under construction. The amount of uranium fuel used would serve as the basis of taxation. Holm and Ollikainen introduce two tax models, adjustable in a manner that the uranium tax would yield revenues of approximately EUR 100 million a year. The companies would still keep more than half of the profit and the state, depending on the model used, would collect 43 to 45 per cent of it via the tax. In the minimum tax model, the uranium tax is 44.5 of the difference between the market price of emission allowance and the average price of 2010 (EUR 15/tonne of CO 2 ), used as the comparison price, the minimum being EUR 2/MWh. The tax would yield a minimum of EUR 67 million to the state a year. When the emission allowance price rises to EUR 30, the tax would be EUR 6.7/MWh and the state would earn revenues of EUR 223 million. In a flexible tax model, the fixed part of the

A generic model of contaminant migration from uranium tailings impoundments

International Nuclear Information System (INIS)

Shepherd, T.A.; Brown, S.E.

1982-01-01

This paper presents an analytical hydrogeochemical model based upon acid consumption-neutralization front movement. The development of contaminant plumes is discussed and distinct zones within these plumes are identified and characterized. The most important process influencing the rate and extent of contaminant migration at acid-leach uranium tailings impoundments is the neutralization of seepage water by soils along ground water flow paths. The chemical characteristics of the ground water is determined in order to identify and characterize zones within migrating plumes of tailings-derived water. It is concluded that the characterization of specific zones is useful in the interpretation of existing conditions, in the evaluation of future migration, and in the determination of appropriate models for the specific situation

Uranium

International Nuclear Information System (INIS)

Toens, P.D.

1981-03-01

The geological setting of uranium resources in the world can be divided in two basic categories of resources and are defined as reasonably assured resources, estimated additional resources and speculative resources. Tables are given to illustrate these definitions. The increasing world production of uranium despite the cutback in the nuclear industry and the uranium requirements of the future concluded these lecture notes

Effects of technological learning and uranium price on nuclear cost: Preliminary insights from a multiple factors learning curve and uranium market modeling

International Nuclear Information System (INIS)

Kahouli, Sondes

2011-01-01

This paper studies the effects of returns to scale, technological learning, i.e. learning-by-doing and learning-by-searching, and uranium price on the prospects of nuclear cost decrease. We use an extended learning curve specification, named multiple factors learning curve (MFLC). In a first stage, we estimate a single MFLC. In a second stage, we estimate the MFLC under the framework of simultaneous system of equations which takes into account the uranium supply and demand. This permits not only to enhance the reliability of the estimation by incorporating the uranium price formation mechanisms in the MFLC via the price variable, but also to give preliminary insights about uranium supply and demand behaviors and the associated effects on the nuclear expansion. Results point out that the nuclear cost has important prospects for decrease via capacity expansion, i.e. learning-by-doing effects. In contrast, they show that the learning-by-searching as well as the scale effects have a limited effect on the cost decrease prospects. Conversely, results also show that uranium price exerts a positive and significant effect on nuclear cost, implying that when the uranium price increases, the nuclear power generation cost decreases. Since uranium is characterized by important physical availability, and since it represents only a minor part in the total nuclear cost, we consider that in a context of increasing demand for nuclear energy the latter result can be explained by the fact that the positive learning effects on the cost of nuclear act in a way to dissipate the negative ones that an increase in uranium price may exert. Further, results give evidence of important inertia in the supply and demand sides as well as evidence of slow correlation between the uranium market and oil market which may limit the inter-fuels substituability effects, that is, nuclear capacity expansion and associated learning-by-doing benefits. - Highlights: → We study the prospects of nuclear cost

The role of GIS in spatial modeling of multi-disciplinary geoscientific data for uranium exploration over the Kunjar-Darjing basin, Odisha

International Nuclear Information System (INIS)

Chaturvedi, Anand Kumar; Veldi, Ramesh Babu; Amulotu, Markandeyulu; Chaki, Anjan; Pavanaguru, R.

2015-01-01

Application of Geographical Information System (GIS) for identifying the spatial locations of uranium exploration target areas using multi-disciplinary geoscientific data is presented in this paper. The data sets used in this study are Airborne Gamma Ray Spectrometric (AGRS), Aeromagnetic (AM), Satellite images, regional ground gravity and geochemical surveys over one of the promising mobile Proterozoic Kunjar-Darjing Basins to the west of Singhbum Uranium Province (SUP), Odisha, India. Analysis of the geochemical data indicated unconformity related uranium mineralization along the unconformity between Kunjar-Darjing sediments and the S-type per-aluminous Tamparkola granite with labile uranium. All the data sets are processed and interpreted independently in terms of geology based on characteristics such as intensity, frequency and texture of the images generated. Various ratio maps generated from AGRS data were used as training points for spatial modeling by building relationships (topology) with the structures and geology interpreted from the magnetic and gravity datasets. Index overlay method is adapted in spatial modeling. The study shows that integrating the geological, geophysical, geochemical and other geodata in a GIS environment provides valuable guidelines for geological mapping as well as identifying target areas for uranium exploration. The GIS study facilitated in identifying potential target areas for uranium exploration along the regional faults D1 and D2 around the villages Kelo, Tarnra, northeast of Kunjar, Nuarali and Betajharan. (author)

Development of system on predicting uranium concentration from pregnant solution

International Nuclear Information System (INIS)

Yi Weiping

2004-01-01

Uranium concentration from pregnant solution is primary index of process for in-situ leaching of uranium, and the suitable method with which to predicate this index and effective means to solve it with were continuously studied hard. SPUC-system on predicting uranium concentration based on GM model of gray system theory is developed, and the mathematical model, constitution, function and theory foundation of this system are introduced. (authors)

Recovery of uranium from uranium bearing black shale

International Nuclear Information System (INIS)

Das, Amrita; Yadav, Manoj; Singh, Ajay K.

2016-01-01

Black shale is the unconventional resource of uranium. Recovery of uranium from black shale has been carried out by the following steps: i) size reduction, ii) leaching of uranium in the aqueous medium, iii) fluoride ion removal, iv) solvent extraction of uranium from the aqueous leach solution, v) scrubbing of the loaded solvent after extraction to remove impurities as much as possible and vi) stripping of uranium from the loaded organic into the aqueous phase. Leaching of black shale has been carried out in hydrochloric acid. Free acidity of the leach solution has been determined by potentiometric titration method. Removal of fluoride ions has been done using sodium chloride. Solvent extraction has been carried out by both tributyl phosphate and alamine-336 as extractants. Scrubbing has been tried with oxalic acid and sulphuric acid. Stripping with sodium carbonate solution has been carried out. Overall recovery of uranium is 95%. (author)

Estimation of uranium forms in oceanic water

International Nuclear Information System (INIS)

Krylov, O.T.; Novikov, P.D.; Nesterova, M.P.

1985-01-01

A critical consideration is given to the notions about uranium forms in ocean water. To estimate uranium forms a model is suggested which takes into account possjble formation of complexes of uranyl ions and ocean water anions Cl - , SO 4 2- , CO 3 2- , HCO 3 - , OH - , F - . The available published data are used to estimate necessary thermodynamic stability constants of the complexes, activity coefficients and concentration of componenets. The thermodynamic calculation shows that uranium hydroxocomplex compounds UO 2 (OH) 4 2- (99.17%) and UO 2 (OH) 3 - (083%) are the most probable uranium forms in ocear water of 34.3% salinity at 25 deg C and 1 atm pressure

Uranium resources, 1983

International Nuclear Information System (INIS)

1983-01-01

The specific character of uranium as energy resources, the history of development of uranium resources, the production and reserve of uranium in the world, the prospect regarding the demand and supply of uranium, Japanese activity of exploring uranium resources in foreign countries and the state of development of uranium resources in various countries are reported. The formation of uranium deposits, the classification of uranium deposits and the reserve quantity of each type are described. As the geological environment of uranium deposits, there are six types, that is, quartz medium gravel conglomerate deposit, the deposit related to the unconformity in Proterozoic era, the dissemination type magma deposit, pegmatite deposit and contact deposit in igneaus rocks and metamorphic rocks, vein deposit, sandstone type deposit and the other types of deposit. The main features of respective types are explained. The most important uranium resources in Japan are those in the Tertiary formations, and most of the found reserve belongs to this type. The geological features, the state of yield and the scale of the deposits in Ningyotoge, Tono and Kanmon Mesozoic formation are reported. Uranium minerals, the promising districts in the world, and the matters related to the exploration and mining of uranium are described. (Kako, I.)

Genetic models and their impact on uranium exploration in the Athabasca sandstone basin, Saskatchewan, Canada

International Nuclear Information System (INIS)

Strnad, J.G.

1980-01-01

While the Beaverlodge area of Northern Saskatchewan became an important uranium-producing district during the 1950s, the Athabasca sandstone basin, located in the immediate vicinity, was considered to be non-prospective in Canada's regional assessment. Twenty years later, with the introduction of the supergene model into the basin's exploration strategy, the favourability of the host-rock for uranium deposits was shown. However, in some instances the search for local targets was enriched by implementing non-supergene models. Most geologists originally favoured the Middle Proterozoic (sub-Helikian) unconformity as a unique ore-controlling feature. Later, the concept of Lower Proterozoic (Aphebian) syngenetic protore, as represented by graphite-bearing strata in Archaean proximity, was added. In the author's view the combination of these factors is productive only within specialized segments of Archaean-Lower Proterozoic (Archaean-Aphebian) contact zones. (author)

Uranium management activities

International Nuclear Information System (INIS)

Jackson, D.; Marshall, E.; Sideris, T.; Vasa-Sideris, S.

2001-01-01

One of the missions of the Department of Energy's (DOE) Oak Ridge Office (ORO) has been the management of the Department's uranium materials. This mission has been accomplished through successful integration of ORO's uranium activities with the rest of the DOE complex. Beginning in the 1980's, several of the facilities in that complex have been shut down and are in the decommissioning process. With the end of the Cold War, the shutdown of many other facilities is planned. As a result, inventories of uranium need to be removed from the Department facilities. These inventories include highly enriched uranium (HEU), low enriched uranium (LEU), normal uranium (NU), and depleted uranium (DU). The uranium materials exist in different chemical forms, including metals, oxides, solutions, and gases. Much of the uranium in these inventories is not needed to support national priorities and programs. (author)

Groundwater modeling for the long-term safety assessment of uranium tailings ponds

International Nuclear Information System (INIS)

Nair, R.N.

2010-01-01

Uranium tailings ponds contain naturally occurring long lived radionuclides such as 238 U, 234 U, 230 Th and 226 Ra as sources which are the parents of a very long radionuclide decay chain. Uranium tailings ponds by the virtue of the longevity of its contents may pose as a long-term radiological hazard if not designed and monitored properly. The principal radiation risks from uranium tailings are gamma radiation: windblown radioactive dust dispersion; and radon gas and its progenies. Uranium tailings ponds are also a major source of surface and groundwater contamination due to leaching of radioactive and other toxic elements. In many countries, the tailings ponds are designed to control the radiological hazards for up to 1000 years, to the extent achievable, and in any case for at least 200 years. Stringent regulations stipulations exist worldwide for the safe design, operation and closure of uranium tailings ponds. The long- term radiological impact assessment of uranium tailings ponds, hence, is an extremely important exercise in uranium mining industry. The simulations conducted for uranium over a period of 1000 years indicate that contaminant fronts from the source with a paste permeability of 1x10 -4 m/day would migrate a probable distance of less than 50 m. The maximum computed distance for this case is less than 300 m. Indian studies show that the total annual effective dose to members of the public at 1.0 km from the centre of the tailings pond is trivial up to a period of 4000 y. The estimated dose is 0.01 mSv/y after 10,000 years and it is 10 times lower than 0.1 mSv/y, which is considered as a safe dose limit for drinking water pathway. (author)

Provision by the uranium and uranium products

International Nuclear Information System (INIS)

Elagin, Yu.P.

2005-01-01

International uranium market is converted from the buyer market into the seller market. The prices of uranium are high and the market attempts to adapt to changing circumstances. The industry of uranium enrichment satisfies the increasing demands but should to increase ots capacities. On the whole the situation is not stable and every year may change the existing position [ru

Exhaustible-resource theory and the uranium market

International Nuclear Information System (INIS)

Hsieh, Y.L.

1982-01-01

Exhaustible-resource theory has been developed rapidly by economists since the OPEC shocks of 1973-1974 and the theory now provides a framework for analyzing the optimal production pattern for resource commodities. However, applications of the theory to particular markets, such as crude oil, have not provided accurate predictions due no doubt to theoretical problems in explaining exploration and discovery events, market organization changes, and uncertainty. This thesis investigated the uranium market in an effort to determine how well the exhaustible-resource theory explains the past price and quantity time paths of this energy resource, and what might be expected in the future. The exhaustible-resource theory was first developed in a form appropriate to an application to the uranium market. An econometric simulation model that combines the history of uranium price formation and the exhaustible-resource theory was developed to forecast future uranium prices. The model was designed not only to reflect the physical processes of drilling activities, changing reserves, production, and prices of uranium through individual equations, but also to account for the interaction of all these interrelationships at the same time

Uranium industry framework

International Nuclear Information System (INIS)

Riley, K.

2008-01-01

The global uranium market is undergoing a major expansion due to an increase in global demand for uranium, the highest uranium prices in the last 20 years and recognition of the potential greenhouse benefits of nuclear power. Australia holds approximately 27% of the world's uranium resources (recoverable at under US$80/kg U), so is well placed to benefit from the expansion in the global uranium market. Increasing exploration activity due to these factors is resulting in the discovery and delineation of further high grade uranium deposits and extending Australia's strategic position as a reliable and safe supplier of low cost uranium.

High-temperature thermal conductivity of uranium chromite and uranium niobate

International Nuclear Information System (INIS)

Fedoseev, D.V.; Varshavskaya, I.G.; Lavrent'ev, A.V.; Oziraner, S.N.; Kuznetsova, D.G.

1979-01-01

The technique of determining thermal conductivity coefficient of uranium niobate and uranium chromite on heating with laser radiation is described. Determined is the coefficient of free-convective heat transfer (with provision for a conduction component) by means of a standard specimen. The thermal conductivity coefficients of uranium chromite and niobate were measured in the 1300-1700 K temperature range. The results are presented in a diagram form. It has been calculated, that the thermal conductivity coefficient for uranium niobate specimens is greater in comparison with uranium chromite specimens. The thermal conductivity coefficients of the materials mentioned depend on temperature very slightly. Thermal conductivity of the materials considerably depends on their porosity. The specimens under investigation were fabricated by the pressing method and had the following porosity: uranium chromite - 30 %, uranium niobate - 10 %. Calculation results show, that thermal conductivity of dense uranium chromite is higher than thermal conductivity of dense uranium niobate. The experimental error equals approximately 20 %, that is mainly due to the error of measuring the temperature equal to +-25 deg, with a micropyrometer

Study of reactions between uranium-plutonium mixed oxide and uranium nitride and between uranium oxide and uranium nitride; Etude des reactions entre l`oxyde mixte d`uranium-plutonium et le nitrure d`uranium et entre l`oxyde d`uranium et le nitrure d`uranium

Energy Technology Data Exchange (ETDEWEB)

Lecraz, C

1993-06-11

A new type of combustible elements which is a mixture of uranium nitride and uranium-plutonium oxide could be used for Quick Neutrons Reactors. Three different studies have been made on the one hand on the reactions between uranium nitride (UN) and uranium-plutonium mixed oxide (U,Pu)O{sub 2}, on the other hand on these between UN and uranium oxide UO{sub 2}. They show a sizeable reaction between nitride and oxide for the studied temperatures range (1573 K to 1973 K). This reaction forms a oxynitride compound, MO{sub x} N{sub y} with M=U or M=(U,Pu), whose crystalline structure is similar to oxide`s. Solubility of nitride in both oxides is studied, as the reaction kinetics. (TEC). 32 refs., 48 figs., 22 tabs.

Uranium Sequestration by Aluminum Phosphate Minerals in Unsaturated Soils

International Nuclear Information System (INIS)

Jerden, James L. Jr.

2007-01-01

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

Current uranium activities in Pakistan

International Nuclear Information System (INIS)

Moghal, M.Y.

2001-01-01

The rocks of Siwaliks group in Pakistan, extending from Kashmir in the east through Potwar Plateau, Bannu Basin and Sulaiman range up to the Arabian Sea in the west have been extensively explored for uranium. The Dhok Pathan Formation, which is younger member of the middle Siwaliks has been aeroradiometrically surveyed and extensively prospected on foot. A large number of anomalies were encountered in Kashmir, Potwar Plateau, Bannu Basin and Sulaiman range. While exploratory work in Sulaiman range and Bannu Basin yielded a few workable deposits, none of the anomalous areas yielded an ore grade concentration in Potwar Plateau. As conventional exploration activities in Potwar Plateau did not yield any ore grade concentration therefore a resource potential evaluation programme through geological modeling was started under the guidance of an IAEA expert. The volcanic material found in the middle Siwaliks is considered to be the main source of uranium and siliceous cement in the sandstones. These findings have considerably increased uranium potential in Siwaliks. The tectonic deformation during and after the deposition of Siwaliks is considered to be the main reason for mobilization of uranium, while permeability barriers and upward movement of oil products may provide trappings for the mobilized uranium. Through this survey south western part of Potwar Plateau being relatively less deformed is considered to provide conducive environments for concentration of uranium. Low grade uranium concentrations have also been discovered in carbonatites in northern part of Pakistan. Preliminary exploration in Sallai Patti carbonatite through drilling supplemented by trenching, pitting and aditing, subsurface continuation of surface concentrations has been confirmed. The ore contains about 200 ppm of uranium and 3 to 4% phosphate in addition to magnetite, rare metals and rare earths. It has been demonstrated on laboratory/pilot scale that the concentrations of uranium and phosphate

Uranium rich granite and uranium productive granite in south China

Energy Technology Data Exchange (ETDEWEB)

Mingyue, Feng; Debao, He [CNNC Key Laboratory of Uranium Resource Exploration and Evaluation Technology, Beijing Research Institute of Uranium Geology (China)

2012-07-15

The paper briefly introduces the differences between uranium rich granite and uranium productive granite in the 5 provinces of South China, and discusses their main characteristics in 4 aspects, the uranium productive granite is highly developed in fracture, very strong in alteration, often occurred as two-mica granite and regularly developed with intermediate-basic and acid dikes. The above characteristics distinguish the uranium productive granite from the uranium rich granite. (authors)

Uranium rich granite and uranium productive granite in south China

International Nuclear Information System (INIS)

Feng Mingyue; He Debao

2012-01-01

The paper briefly introduces the differences between uranium rich granite and uranium productive granite in the 5 provinces of South China, and discusses their main characteristics in 4 aspects, the uranium productive granite is highly developed in fracture, very strong in alteration, often occurred as two-mica granite and regularly developed with intermediate-basic and acid dikes. The above characteristics distinguish the uranium productive granite from the uranium rich granite. (authors)

System-Scale Model of Aquifer, Vadose Zone, and River Interactions for the Hanford 300 Area - Application to Uranium Reactive Transport

Energy Technology Data Exchange (ETDEWEB)

Rockhold, Mark L.; Bacon, Diana H.; Freedman, Vicky L.; Parker, Kyle R.; Waichler, Scott R.; Williams, Mark D.

2013-10-01

This report represents a synthesis and integration of basic and applied research into a system-scale model of the Hanford 300 Area groundwater uranium plume, supported by the U.S. Department of Energy’s Richland Operations (DOE-RL) office. The report integrates research findings and data from DOE Office of Science (DOE-SC), Office of Environmental Management (DOE-EM), and DOE-RL projects, and from the site remediation and closure contractor, Washington Closure Hanford, LLC (WCH). The three-dimensional, system-scale model addresses water flow and reactive transport of uranium for the coupled vadose zone, unconfined aquifer, and Columbia River shoreline of the Hanford 300 Area. The system-scale model of the 300 Area was developed to be a decision-support tool to evaluate processes of the total system affecting the groundwater uranium plume. The model can also be used to address “what if” questions regarding different remediation endpoints, and to assist in design and evaluation of field remediation efforts. For example, the proposed cleanup plan for the Hanford 300 Area includes removal, treatment, and disposal of contaminated sediments from known waste sites, enhanced attenuation of uranium hot spots in the vadose and periodically rewetted zone, and continued monitoring of groundwater with institutional controls. Illustrative simulations of polyphosphate infiltration were performed to demonstrate the ability of the system-scale model to address these types of questions. The use of this model in conjunction with continued field monitoring is expected to provide a rigorous basis for developing operational strategies for field remediation and for defining defensible remediation endpoints.

Uranium industry annual 1996

International Nuclear Information System (INIS)

1997-04-01

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

Uranium industry annual 1996

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-04-01

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

To meet new tasks of scientific research on uranium geology in new century

International Nuclear Information System (INIS)

Chen Zuyi

2000-01-01

The author analyses the new situation that the scientific research on uranium geology is facing in the coming new century, and proposes that the guiding idea of the scientific research on uranium geology is to coordinate the general policy of Bureau of Geology--to give the first priority to in-situ leachable sandstone-type uranium deposits. The specific tasks for the scientific research on uranium geology are: to implement regional evaluation and target area selection of in-situ leachable sandstone-type uranium deposits; to develop new techniques and methods of detecting buried in-situ leachable sandstone-type uranium deposits; to turn the genetic model of uranium deposit and deposit model to prospecting model; to strengthen the research on economic geology and the dynamic assessment system of uranium resources and to build up and improve the data base of Meso-Cenozoic basins and sandstone-type uranium deposits. In order to guarantee the successful implementation of the above tasks it is necessary for the Beijing Research Institute of Uranium Geology--the leading unit in scientific research on uranium geology to accelerate bringing up large numbers of young outstanding researchers; to have clear consciousness of market economy and product quality; to given play to advantages of qualified personnel, advanced equipment and modern technology

Research on uranium resource models. Part IV. Logic: a computer graphics program to construct integrated logic circuits for genetic-geologic models. Progress report

International Nuclear Information System (INIS)

Scott, W.A.; Turner, R.M.; McCammon, R.B.

1981-01-01

Integrated logic circuits were described as a means of formally representing genetic-geologic models for estimating undiscovered uranium resources. The logic circuits are logical combinations of selected geologic characteristics judged to be associated with particular types of uranium deposits. Each combination takes on a value which corresponds to the combined presence, absence, or don't know states of the selected characteristic within a specified geographic cell. Within each cell, the output of the logic circuit is taken as a measure of the favorability of occurrence of an undiscovered deposit of the type being considered. In this way, geological, geochemical, and geophysical data are incorporated explicitly into potential uranium resource estimates. The present report describes how integrated logic circuits are constructed by use of a computer graphics program. A user's guide is also included

Production of sized particles of uranium oxides and uranium oxyfluorides

International Nuclear Information System (INIS)

Knudsen, I.E.; Randall, C.C.

1976-01-01

A process is claimed for converting uranium hexafluoride (UF 6 ) to uranium dioxide (UO 2 ) of a relatively large particle size in a fluidized bed reactor by mixing uranium hexafluoride with a mixture of steam and hydrogen and by preliminary reacting in an ejector gaseous uranium hexafluoride with steam and hydrogen to form a mixture of uranium and oxide and uranium oxyfluoride seed particles of varying sizes, separating the larger particles from the smaller particles in a cyclone separator, recycling the smaller seed particles through the ejector to increase their size, and introducing the larger seed particles from the cyclone separator into a fluidized bed reactor where the seed particles serve as nuclei on which coarser particles of uranium dioxide are formed. 9 claims, 2 drawing figures

Uranium 2000 : International symposium on the process metallurgy of uranium

International Nuclear Information System (INIS)

Ozberk, E.; Oliver, A.J.

2000-01-01

The International Symposium on the Process Metallurgy of Uranium has been organized as the thirtieth annual meeting of the Hydrometallurgy Section of the Metallurgical Society of the Canadian Institute of Mining, Metallurgy and Petroleum (CIM). This meeting is jointly organized with the Canadian Mineral Processors Division of CIM. The proceedings are a collection of papers from fifteen countries covering the latest research, development, industrial practices and regulatory issues in uranium processing, providing a concise description of the state of this industry. Topics include: uranium industry overview; current milling operations; in-situ uranium mines and processing plants; uranium recovery and further processing; uranium leaching; uranium operations effluent water treatment; tailings disposal, water treatment and decommissioning; mine decommissioning; and international regulations and decommissioning. (author)

Development and testing af a model for the supergene distribution of uranium and accompanying elements around a known uranium deposit associated with an alkaline intrusion

International Nuclear Information System (INIS)

Rose-Hansen, J.; Soerensen, H.

1983-01-01

The Ilimaussaq intrusion may be characterized as a geochemically abnormal region, since its rocks are strongly enriched in a number of rare elements, including elements which accompany uranium in deposits in other parts of the world. Examples are the rare earth metals, Nb, Ta, Be, Li, and metals as Cu, Pb, Zn, Mo and Sn. It was proposed to develop and test a model for the supergene distribution of uranium and accompanying elements around a known uranium deposit associated with an alkaline intrusion. The most promising results are those obtained by the PCA technique. For a more preliminary study of a region fjord and river sediments might be the sampling target. These sediments were found to be mixtures in which the proportion of material from the Ilimaussaq U-deposit could be evaluated by the PCA technique involving a distance function related to the loadings in the first principal dimen- sion of the elements characterizing the Ilimaussaq Intrusion. One of the major features of the material sampled in this study is the general high degree of preservation in the sub-arctic environment of the primary igneous mineralogy in the sediments, and in other areas, the structure of data should be investigated in order to test them in this respect. One obvious way is X-ray diffraction analysis. It was indicated that uranium is selectively absorbed on the organic material in lakes and is able to reflect the concentration of U in the lake waters, informing the ultimate potential of the drainage areas in question. It is however yet to be established whether the correlation of uranium and the organic material of the lake sediments actually reflects the long term U concentrations of the lake water. The use of the cluster analysis and discriminant analysis techniques proved to be of lesser value in this project. (author)

Retention and reduction of uranium on pyrite surface

International Nuclear Information System (INIS)

Eglizaud, N.

2006-12-01

In the hypothesis of a storage of the spent fuel in a deep geological formation, understanding the uranium dispersion in the environment is important. Pyrite is a reducing mineral present in the Callovo-Oxfordian argilites, the geological formation actually studied for such a storage. However, pyrite impact on uranium migration has already been poorly studied. The aim of the study was to understand the mechanisms of uranium(VI) retention and reduction on the pyrite surface (FeS 2 ). Solution chemistry was therefore coupled with solid spectroscopic studies (XPS and Raman spectroscopy). All uranium-pyrite interactions experiments were performed under an anoxic atmosphere, in a glove box. Pyrite dissolution under anoxic conditions releases sulfoxy-anions and iron(II), which can then be adsorbed on the pyrite surface. This adsorption was confirmed by interaction experiments using iron(II) isotopic dilution. Uranium(VI) is retained by an exchange reaction with iron(II) adsorbed on sulphur sites, with a maximal amount of sorbed uranium at pH ≥ 5.5. Cobalt(II) and europium(III) are also adsorbed on the pyrite surface above pH 5.5 confirming then that reduction is not required for species to adsorb on pyrite. When the concentration of uranium retained is lower than 4 x 10 -9 mol g -1 , an oxidation-reduction reaction leads to the formation of a uranium (VI) (IV) mixed oxide and to solid sulphur (d.o. ≥ -I). During this reaction, iron remains mostly at the +II oxidation degree. The reaction products seem to passivate the pyrite surface: at higher amounts of retained uranium, the oxidation-reduction reaction is no longer observed. The surface is saturated by the retention of (3.4 ± 0.8) x 10 -7 mol L -1 of uranium(VI). Modelling of uranium sorption at high surface coverage (≥ 4 x 10 -9 mol g -1 ) by the Langmuir model yields an adsorption constant of 8 x 10 7 L mol -1 . Finally, a great excess of uranium(VI) above the saturation concentration allows the observation of

Uranium partitioning under acidic conditions in a sandy soil aquifer

International Nuclear Information System (INIS)

Johnson, W.H.; Serkiz, S.M.; Johnson, L.M.

1995-01-01

The partitioning of uranium in an aquifer down gradient of two large mixed waste sites was examined with respect to the solution and soil chemistry (e.g., pH redox potential and contaminant concentration) and aqueous-phase chemical speciation. This involved generation of field-derived, batch sorption, and reactive mineral surface sorption data. Field-derived distribution coefficients for uranium at these waste sites were found to vary between 0.40 and 15,000. Based on thermodynamic speciation modeling and a comparison of field and laboratory data, gibbsite is a potential reactive mineral surface present in modified soils at the sites. Uranium partitioning data are presented from field samples and laboratory studies of background soil and the mineral surface gibbsite. Mechanistic and empirical sorption models fit to the field-derived uranium partitioning data show an improvement of over two orders of magnitude, as measured by the normalized sum of errors squared, when compared with the single K d model used in previous risk work. Models fit to batch sorption data provided a better fit of sorbed uranium than do models fit to the field-derived data

Elevated Uranium in Aquifers of the Jacobsville Sandstone

Science.gov (United States)

Sherman, H.; Gierke, J.

2003-12-01

The EPA has announced a new standard for uranium in drinking water of 30 parts per billion (ppb). This maximum contaminant level (MCL) takes effect for community water supplies December 2003. The EPA's ruling has heightened awareness among residential well owners that uranium in drinking water may increase the risk of kidney disease and cancer and has created a need for a quantified, scientific understanding of the occurrence and distribution of uranium isotopes in aquifers. The authors are investigating the occurrence of elevated uranium in northern Michigan aquifers of the Middle Proterozoic Jacobsville sandstone, a red to mottled sequence of sandstones, conglomerates, siltstones and shales deposited as basin fill in the 1.1 Ga Midcontinent rift. Approximately 25% of 300 well water samples tested for isotopic uranium have concentrations above the MCL. Elevated uranium occurrences are distributed throughout the Jacobsville sandstone aquifers stretching across Michigan's Upper Peninsula. However, there is significant variation in well water uranium concentrations (from 0.01 to 190 ppb) and neighboring wells do not necessarily have similar concentrations. The authors are investigating hydrogeologic controls on ground water uranium concentrations in the Jacobsville sandstone, e.g. variations in lithology, mineralogy, groundwater residence time and geochemistry. Approximately 2000' of Jacobsville core from the Amoco St. Amour well was examined in conjunction with the spectral gamma ray log run in the borehole. Spikes in equivalent uranium (eU) concentration from the log are frequently associated with clay and heavy mineral layers in the sandstone core. The lithology and mineralogy of these layers will be determined by analysis of thin sections and x-ray diffraction. A portable spectrometer, model GRS-2000/BL, will be used on the sandstone cliffs along Lake Superior to characterize depositional and lithologic facies of the Jacobsville sandstone in terms of

Uranium Industry Annual, 1992

International Nuclear Information System (INIS)

1993-01-01

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

Uranium Industry Annual, 1992

Energy Technology Data Exchange (ETDEWEB)

1993-10-28

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

Depleted uranium

International Nuclear Information System (INIS)

Huffer, E.; Nifenecker, H.

2001-02-01

This document deals with the physical, chemical and radiological properties of the depleted uranium. What is the depleted uranium? Why do the military use depleted uranium and what are the risk for the health? (A.L.B.)

Pyrophoric behaviour of uranium hydride and uranium powders

Science.gov (United States)

Le Guyadec, F.; Génin, X.; Bayle, J. P.; Dugne, O.; Duhart-Barone, A.; Ablitzer, C.

2010-01-01

Thermal stability and spontaneous ignition conditions of uranium hydride and uranium metal fine powders have been studied and observed in an original and dedicated experimental device placed inside a glove box under flowing pure argon. Pure uranium hydride powder with low amount of oxide (Oxidation mechanisms are proposed.

Descriptive models of major uranium deposits in China - Some results of the Workshop on Uranium Resource Assessment sponsored by the International Atomic Energy Agency, Vienna, Austria, in cooperation with China National Nuclear Corporation, Beijing, and the U.S. Geological Survey, Denver, Colorado, and Reston, Virginia

Science.gov (United States)

Finch, W.I.; Feng, S.; Zuyi, C.; McCammon, R.B.

1993-01-01

Four major types of uranium deposits occur in China: granite, volcanic, sandstone, and carbonaceous-siliceous-pelitic rock. These types are major sources of uranium in many parts of the world and account for about 95 percent of Chinese production. Descriptive models for each of these types record the diagnostic regional and local geologic features of the deposits that are important to genetic studies, exploration, and resource assessment. A fifth type of uranium deposit, metasomatite, is also modeled because of its high potential for production. These five types of uranium deposits occur irregularly in five tectonic provinces distributed from the northwest through central to southern China. ?? 1993 Oxford University Press.

RECOVERY OF URANIUM FROM ZIRCONIUM-URANIUM NUCLEAR FUELS

Science.gov (United States)

Gens, T.A.

1962-07-10

An improvement was made in a process of recovering uranium from a uranium-zirconium composition which was hydrochlorinated with gsseous hydrogen chloride at a temperature of from 350 to 800 deg C resulting in volatilization of the zirconium, as zirconium tetrachloride, and the formation of a uranium containing nitric acid insoluble residue. The improvement consists of reacting the nitric acid insoluble hydrochlorination residue with gaseous carbon tetrachloride at a temperature in the range 550 to 600 deg C, and thereafter recovering the resulting uranium chloride vapors. (AEC)

Retention and reduction of uranium on pyrite surface; Retention et reduction de l'uranium a la surface de la pyrite

Energy Technology Data Exchange (ETDEWEB)

Eglizaud, N

2006-12-15

In the hypothesis of a storage of the spent fuel in a deep geological formation, understanding the uranium dispersion in the environment is important. Pyrite is a reducing mineral present in the Callovo-Oxfordian argilites, the geological formation actually studied for such a storage. However, pyrite impact on uranium migration has already been poorly studied. The aim of the study was to understand the mechanisms of uranium(VI) retention and reduction on the pyrite surface (FeS{sub 2}). Solution chemistry was therefore coupled with solid spectroscopic studies (XPS and Raman spectroscopy). All uranium-pyrite interactions experiments were performed under an anoxic atmosphere, in a glove box. Pyrite dissolution under anoxic conditions releases sulfoxy-anions and iron(II), which can then be adsorbed on the pyrite surface. This adsorption was confirmed by interaction experiments using iron(II) isotopic dilution. Uranium(VI) is retained by an exchange reaction with iron(II) adsorbed on sulphur sites, with a maximal amount of sorbed uranium at pH {>=} 5.5. Cobalt(II) and europium(III) are also adsorbed on the pyrite surface above pH 5.5 confirming then that reduction is not required for species to adsorb on pyrite. When the concentration of uranium retained is lower than 4 x 10{sup -9} mol g{sup -1}, an oxidation-reduction reaction leads to the formation of a uranium (VI) (IV) mixed oxide and to solid sulphur (d.o. {>=} -I). During this reaction, iron remains mostly at the +II oxidation degree. The reaction products seem to passivate the pyrite surface: at higher amounts of retained uranium, the oxidation-reduction reaction is no longer observed. The surface is saturated by the retention of (3.4 {+-} 0.8) x 10{sup -7} mol L{sup -1} of uranium(VI). Modelling of uranium sorption at high surface coverage ({>=} 4 x 10{sup -9} mol g{sup -1}) by the Langmuir model yields an adsorption constant of 8 x 10{sup 7} L mol{sup -1}. Finally, a great excess of uranium(VI) above the

Acidic aqueous uranium electrodeposition for target fabrication

International Nuclear Information System (INIS)

Saliba-Silva, A.M.; Oliveira, E.T.; Garcia, R.H.L.; Durazzo, M.

2013-01-01

Direct irradiation of targets inside nuclear research or multiple purpose reactors is a common route to produce 99 Mo- 99m Tc radioisotopes. The electroplating of low enriched uranium over nickel substrate might be a potential alternative to produce targets of 235 U. The electrochemistry of uranium at low temperature might be beneficial for an alternative route to produce 99 Mo irradiation LEU targets. Electrodeposition of uranium can be made using ionic and aqueous solutions producing uranium oxide deposits. The performance of uranium electrodeposition is relatively low because a big competition with H 2 evolution happens inside the window of electrochemical reduction potential. This work explores possibilities of electroplating uranium as UO 2 2+ (Uranium-VI) in order to achieve electroplating uranium in a sufficient amount to be commercially irradiated in the future Brazilian RMB reactor. Electroplated nickel substrate was followed by cathodic current electrodeposition from aqueous UO 2 (NO 3 ) 2 solution. EIS tests and modeling showed that a film formed differently in the three tested cathodic potentials. At the lower level, (-1.8V) there was an indication of a double film formation, one overlaying the other with ionic mass diffusion impaired at the interface with nickel substrate as showed by the relatively lower admittance of Warburg component. (author)

Can we predict uranium bioavailability based on soil parameters? Part 2: soil solution uranium concentration is not a good bioavailability index.

Science.gov (United States)

Vandenhove, H; Van Hees, M; Wannijn, J; Wouters, K; Wang, L

2007-01-01

The present study aimed to quantify the influence of soil parameters on uranium uptake by ryegrass. Ryegrass was established on eighteen distinct soils, spiked with (238)U. Uranium soil-to-plant transfer factors (TF) ranged from 0.0003 to 0.0340kgkg(-1). There was no significant relation between the U soil-to-plant transfer (or total U uptake or flux) and the uranium concentration in the soil solution or any other soil factor measured, nor with the U recovered following selective soil extractions. Multiple linear regression analysis resulted in a significant though complex model explaining up to 99% of variation in TF. The influence of uranium speciation on uranium uptake observed was featured: UO(2)(+2), uranyl carbonate complexes and UO(2)PO(4)(-) seem the U species being preferentially taken up by the roots and transferred to the shoots. Improved correlations were obtained when relating the uranium TF with the summed soil solution concentrations of mentioned uranium species.

Uranium prospecting; La prospection de l'uranium

Energy Technology Data Exchange (ETDEWEB)

Roubault, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1955-07-01

This report is an instruction book for uranium prospecting. It appeals to private prospecting. As prospecting is now a scientific and technical research, it cannot be done without preliminary studies. First of all, general prospecting methods are given with a recall of fundamental geologic data and some general principles which are common with all type of prospecting. The peculiarities of uranium prospecting are also presented and in particular the radioactivity property of uranium as well as the special aspect of uranium ores and the aspect of neighbouring ores. In a third part, a description of the different uranium ores is given and separated in two different categories: primary and secondary ores, according to the place of transformation, deep or near the crust surface respectively. In the first category, the primary ores include pitchblende, thorianite and rare uranium oxides as euxenite and fergusonite for example. In the second category, the secondary ores contain autunite and chalcolite for example. An exhaustive presentation of the geiger-Mueller counter is given with the presentation of its different components, its functioning and utilization and its maintenance. The radioactivity interpretation method is showed as well as the elaboration of a topographic map of the measured radioactivity. A brief presentation of other detection methods than geiger-Mueller counters is given: the measurement of fluorescence and a chemical test using the fluorescence properties of uranium salts. Finally, the main characteristics of uranium deposits are discussed. (M.P.)

Estimating Uranium Partition Coefficients from Laboratory Adsorption Isotherms

International Nuclear Information System (INIS)

Hull, L.C.; Grossman, C.; Fjeld, R.A.; Coates, J.T.; Elzerman, A.W.

2002-01-01

An estimated 330 metric tons of uranium have been buried in the radioactive waste Subsurface Disposal Area (SDA) at the Idaho National Engineering and Environmental Laboratory (INEEL). An assessment of uranium transport parameters is being performed to decrease the uncertainty in risk and dose predictions derived from computer simulations of uranium fate and transport to the underlying Snake River Plain Aquifer. Uranium adsorption isotherms have been measured in the laboratory and fit with a Freundlich isotherm. The Freundlich n parameter was statistically identical for 14 sediment samples. The Freundlich Kf for seven samples, where material properties have been measured, is correlated to sediment surface area. Based on these empirical observations, a model has been derived for adsorption of uranium on INEEL sedimentary materials using surface complexation theory. The model was then used to predict the range of adsorption conditions to be expected at the SDA. Adsorption in the deep vadose zone is predicted to be stronger than in near-surface sediments because the total dissolved carbonate decreases with depth

Computational electrochemo-fluid dynamics modeling in a uranium electrowinning cell

International Nuclear Information System (INIS)

Kim, K.R.; Choi, S.Y.; Kim, S.H.; Shim, J.B.; Paek, S.; Kim, I.T.

2014-01-01

A computational electrochemo-fluid dynamics model has been developed to describe the electrowinning behavior in an electrolyte stream through a planar electrode cell system. Electrode reaction of the uranium electrowinning process from a molten-salt electrolyte stream was modeled to illustrate the details of the flow-assisted mass transport of ions to the cathode. This modeling approach makes it possible to represent variations of the convective diffusion limited current density by taking into account the concentration profile at the electrode surface as a function of the flow characteristics and applied current density in a commercially available computational fluid dynamics platform. It was possible to predict the conventional current-voltage relation in addition to details of electrolyte fluid dynamics and electrochemical variables, such as the flow field, species concentrations, potential, and current distributions throughout the galvanostatic electrolysis cell. (author)

Strategy and perspective for uranium exploration in Egypt

International Nuclear Information System (INIS)

Hassan, M.A.; Salman, A.B.; Assaf, H.S.; Mahdy, M.M.

1995-01-01

Uranium exploration started in Egypt about three decades ago. This was performed by applying integrated airborne and ground radiometric prospecting. The latter was conducted upon selected areas having rather favorable geological criteria. These activities resulted in the discovery of great numbers of radiometric anomalies, with several uranium occurrences in various geologic environments in granitic and sedimentary rocks. Some of these uranium occurrences show good potential for developing into workable uranium deposits. Small-scale exploratory tunnelling and drilling works have been carried out at some of these occurrences. Leaching studies and pilot experiments were carried out on technological samples to evaluate ore's suitability for uranium extraction. However, no assured reserves of uranium have been reached yet. The demands for uranium to satisfy the near future Egyptian nuclear power generation necessitates some development in the national strategy for uranium exploration. This will be achieved through intense programmes for ground geophysics and drilling from surface and underground mining works, in addition to radon emanometry and logging of oil and gas wells. Moreover, non conventional procedures for uranium extraction such as heap-leaching may be followed to exploit small-scale uranium deposits. In this developed strategy, the present uranium occurrences are modellized and categorized following the IAEA classification. The characteristics of the present uranium occurrences will be utilized in prospecting new areas. Subsidiary resources in phosphorites, black sands and rare metal deposits could supply additional quantities of uranium, in addition to thorium and rare earth elements. (author). 34 refs, 4 figs, 1 tab

Uranium health physics

International Nuclear Information System (INIS)

1980-01-01

This report contains the papers delivered at the Summer School on Uranium Health Physics held in Pretoria on the 14 and 15 April 1980. The following topics were discussed: uranium producton in South Africa; radiation physics; internal dosimetry and radiotoxicity of long-lived uranium isotopes; uranium monitoring; operational experience on uranium monitoring; dosimetry and radiotoxicity of inhaled radon daughters; occupational limits for inhalation of radon-222, radon-220 and their short-lived daughters; radon monitoring techniques; radon daughter dosimeters; operational experience on radon monitoring; and uranium mill tailings management

Uranium supply and demand

Energy Technology Data Exchange (ETDEWEB)

Spriggs, M J

1976-01-01

Papers were presented on the pattern of uranium production in South Africa; Australian uranium--will it ever become available; North American uranium resources, policies, prospects, and pricing; economic and political environment of the uranium mining industry; alternative sources of uranium supply; whither North American demand for uranium; and uranium demand and security of supply--a consumer's point of view. (LK)

Uranium industry annual, 1991

International Nuclear Information System (INIS)

1992-10-01

In the Uranium Industry Annual 1991, data on uranium raw materials activities including exploration activities and expenditures, resources and reserves, mine production of uranium, production of uranium concentrate, and industry employment are presented in Chapter 1. Data on uranium marketing activities including domestic uranium purchases, commitments by utilities, procurement arrangements, uranium imports under purchase contracts and exports, deliveries to enrichment suppliers, inventories, secondary market activities, utility market requirements, and uranium for sale by domestic suppliers are presented in Chapter 2. A feature article entitled ''The Uranium Industry of the Commonwealth of Independent States'' is included in this report

Gebel Gattar prospect, an obvious model of intra granitic uranium mineralization

Energy Technology Data Exchange (ETDEWEB)

Salman, A A; Shalaby, H M; Noseir, L; Elkhouli, D; Roz, M; Abu Zeid, M; Mostafa, M; Amin, N; Ayoub, R; Khamis, H [Nuclear materials authority, El Maadi, Cairo, (Egypt)

1995-10-01

Gebel Gattar area is situated in the northern Eastern desert, SW Hurghada city and is considered as an area of high potentiality for workable uranium deposits. The field radiometric prospect has started in May 1984. The geologic, structural and radiometric studies have resulted in the northern parts of the pluton and are controlled by some important structural features, namely NNE-SSW, ENE-WSW, NW-SE and to a lesser extent the N-S faults. The uranium content of the fresh granites in the area ranges from 20 to 30 ppm and thus could be considered as uraniferous granites. The mineralized samples are ranging from 1000 to 5000 ppm, while hand piked sample could reach as much as 14000 ppm. Detailed mineralogical studies proved the presence of various types of secondary uranium minerals presented mainly by molybdates, vanadates, silicate and sulphates. Exploratory tunneling works during 1990 to 1992 demonstrated that the uranium mineralization is still persistent from level 900 m (asl) to level 660 m (asl) which is nearly the wadi level. The alteration of the rocks especially hematitization, kaolination and partial silicificant is still well noticed and the gaping of the fault zone is more open and shows an increasing width. Moreover, secondary uranium minerals are still present indicating persistence of the oxidizing conditions. 5 figs., 4 tabs.

Uranium price reporting systems

International Nuclear Information System (INIS)

1987-09-01

This report describes the systems for uranium price reporting currently available to the uranium industry. The report restricts itself to prices for U 3 O 8 natural uranium concentrates. Most purchases of natural uranium by utilities, and sales by producers, are conducted in this form. The bulk of uranium in electricity generation is enriched before use, and is converted to uranium hexafluoride, UF 6 , prior to enrichment. Some uranium is traded as UF 6 or as enriched uranium, particularly in the 'secondary' market. Prices for UF 6 and enriched uranium are not considered directly in this report. However, where transactions in UF 6 influence the reported price of U 3 O 8 this influence is taken into account. Unless otherwise indicated, the terms uranium and natural uranium used here refer exclusively to U 3 O 8 . (author)

Long-term availability of global uranium resources

International Nuclear Information System (INIS)

Monnet, Antoine

2016-01-01

From a global perspective, a low-carbon path to development driven by a growth of nuclear power production raises issues about the availability of uranium resources. Future technologies allowing nuclear reactors to overcome the need for natural uranium will take time to fully deploy. To address these issues, we analyze the conditions of availability of uranium in the 21. century. The first two conditions are technical accessibility and economic interest, both related to the cost of production. We study them using a model that estimates the ultimate uranium resources (amounts of both discovered and undiscovered resources) and their costs. This model splits the world into regions and the resource estimate for each region derives from the present knowledge of the deposits and economic filtering. The output is a long-term supply curve that illustrates the quantities of uranium that are technically accessible as a function of their cost of production. We identify the main uncertainties of these estimates and we show that with no regional breakdown, the ultimate resources are underestimated. The other conditions of availability of uranium covered in our study are related to the market dynamics, i.e. they derive from the supply and demand clearing mechanism. To assess their influence, they are introduced as dynamic constraints in a partial equilibrium model. This model of the uranium market is deterministic, and market players are represented by regions. For instance, it takes into account the short-term correlation between price and exploration expenditures, which is the subject of a dedicate econometric study. In the longer term, constraints include anticipation of demand by consumers and a gradual depletion of the cheapest ultimate resources. Through a series of prospective simulations, we demonstrate the strong influence on long-term price trends of both the growth rate of demand during the 21. century and its anticipation. Conversely, the uncertainties related to the

Formation mechanism of uranium minerals at sandstone-type uranium deposits

International Nuclear Information System (INIS)

Li Shengfu; Zhang Yun

2004-01-01

By analyzing the behavior and existence form of uranium in different geochemical environments, existence form of uranium and uranium minerals species, this paper expounds the formation mechanism of main commercial uranium mineral--pitchblende: (1) uranium is a valence-changeable element. It is reactivated and migrates in oxidized environment, and is reduced and precipitated in reducing environment; (2) [UO 2 (CO 3 ) 3 ] 4- , [UO 2 (CO 3 ) 2 ] 2- coming from oxidized environment react with reductants such as organic matter, sulfide and low-valence iron at the redox front to form simple uranium oxide--pitchblende; (3)the adsorption of uranium by organic matter and clay minerals accelerates the reduction and the concentration of uranium. Therefore, it is considered, that the reduction of SO 4 2- by organic matter to form H 2 S, and the reduction of UO 2 2+ by H 2 S are the main reasons for the formation of pitchblende. This reaction is extensively and universally available in neutral and weakly alkaline carbonate solution. The existense of reductants such as H 2 S is the basic factor leading to the decrease of Eh in environments and the oversaturation of UO 2 2+ at the redox front in groundwater, thus accelerating the adsorption and the precipitation of uranium

The neurotoxicology of uranium

International Nuclear Information System (INIS)

Dinocourt, Céline; Legrand, Marie; Dublineau, Isabelle; Lestaevel, Philippe

2015-01-01

The brain is a target of environmental toxic pollutants that impair cerebral functions. Uranium is present in the environment as a result of natural deposits and release by human applications. The first part of this review describes the passage of uranium into the brain, and its effects on neurological functions and cognitive abilities. Very few human studies have looked at its cognitive effects. Experimental studies show that after exposure, uranium can reach the brain and lead to neurobehavioral impairments, including increased locomotor activity, perturbation of the sleep-wake cycle, decreased memory, and increased anxiety. The mechanisms underlying these neurobehavioral disturbances are not clearly understood. It is evident that there must be more than one toxic mechanism and that it might include different targets in the brain. In the second part, we therefore review the principal mechanisms that have been investigated in experimental models: imbalance of the anti/pro-oxidant system and neurochemical and neurophysiological pathways. Uranium effects are clearly specific according to brain area, dose, and time. Nonetheless, this review demonstrates the paucity of data about its effects on developmental processes and the need for more attention to the consequences of exposure during development.

Uranium enrichment

International Nuclear Information System (INIS)

1990-01-01

This report looks at the following issues: How much Soviet uranium ore and enriched uranium are imported into the United States and what is the extent to which utilities flag swap to disguise these purchases? What are the U.S.S.R.'s enriched uranium trading practices? To what extent are utilities required to return used fuel to the Soviet Union as part of the enriched uranium sales agreement? Why have U.S. utilities ended their contracts to buy enrichment services from DOE?

Contribution of uranium diffusion on creep behaviour of uranium dicarbide

International Nuclear Information System (INIS)

Kurasawa, T.; Kikuchi, T.

1976-01-01

Compressive creep tests of uranium dicarbide (UC 2 ) have been conducted. The general equation best describing the creep rate over the temperature range 1200-1400 0 C and over the stress range 2000-15000psi is represented by the sum of two exponential terms d(epsilon)/dt=A(sigma/E)sup(0.9) exp(-39.6+- 1.0/RT) + B(sigma/E)sup(4.5) exp(-120.6+-1.7/RT), where pre-exponential factors are A(sigma/E)sup(0.9)=12.3/h at low stress region (3000 psi) and B(sigma/E)sup(4.5)=3.17x10 13 /h at high stress region (9000 psi), and the activation energy is given in kcal/mol. Each term of this experimental equation indicates that important processes occurring during the steady state creep are grain-boundary diffusion of the Coble model at low stress region and the Weertman dislocation climb model at high stress region. Both mechanisms are related to migration of uranium vacancies. (Auth.)

Australian uranium industry

Energy Technology Data Exchange (ETDEWEB)

Warner, R K

1976-04-01

Various aspects of the Australian uranium industry are discussed including the prospecting, exploration and mining of uranium ores, world supply and demand, the price of uranium and the nuclear fuel cycle. The market for uranium and the future development of the industry are described.

Uranium enrichment plans

International Nuclear Information System (INIS)

Thomas, D.C.; Gagne, R.W.

1978-01-01

The following topics are covered: the status of the Government's existing uranium enrichment services contracts, natural uranium requirements based on the latest contract information, uncertainty in predicting natural uranium requirements based on uranium enrichment contracts, and domestic and foreign demand assumed in enrichment planning

Can we predict uranium bioavailability based on soil parameters? Part 1: Effect of soil parameters on soil solution uranium concentration

International Nuclear Information System (INIS)

Vandenhove, H.; Hees, M. van; Wouters, K.; Wannijn, J.

2007-01-01

Present study aims to quantify the influence of soil parameters on soil solution uranium concentration for 238 U spiked soils. Eighteen soils collected under pasture were selected such that they covered a wide range for those parameters hypothesised as being potentially important in determining U sorption. Maximum soil solution uranium concentrations were observed at alkaline pH, high inorganic carbon content and low cation exchange capacity, organic matter content, clay content, amorphous Fe and phosphate levels. Except for the significant correlation between the solid-liquid distribution coefficients (K d , L kg -1 ) and the organic matter content (R 2 = 0.70) and amorphous Fe content (R 2 = 0.63), there was no single soil parameter significantly explaining the soil solution uranium concentration (which varied 100-fold). Above pH = 6, log(K d ) was linearly related with pH [log(K d ) = - 1.18 pH + 10.8, R 2 = 0.65]. Multiple linear regression analysis did result in improved predictions of the soil solution uranium concentration but the model was complex. - Uranium solubility in soil can be predicted from organic matter or amorphous iron content and pH or with complex multilinear models considering several soil parameters

Uranium of Kazakhstan

International Nuclear Information System (INIS)

Tsalyuk, Yu.; Gurevich, D.

2000-01-01

Over 25 % of the world's uranium reserves are concentrated in Kazakhstan. So, the world's largest Shu-Sarysu uranium province is situated on southern Kazakhstan, with resources exceeding 1 billion tonnes of uranium. No less, than 3 unique deposits with resources exceeding 100,000 tonnes are situated here. From the economic point of view the most important thing is that these deposits are suitable for in-situ leaching, which is the cheapest, environmentally friendly and most efficient method available for uranium extracting. In 1997 the Kazatomprom National Joint-Stock Company united all Kazakhstan's uranium enterprises (3 mine and concentrating plants, Volkovgeologiya Joint-Stock Company and the Ulbinskij Metallurgical plant). In 1998 uranium production came to 1,500 tonnes (860 kg in 1997). In 1999 investment to the industry were about $ 30 million. Plans for development of Kazakhstan's uranium industry provide a significant role for foreign partners. At present, 2 large companies (Comeco (Canada), Cogema (France) working in Kazakhstan. Kazakatomprom continues to attract foreign investors. The company's administration announced that in that in next year they have plan to make a radical step: to sell 67 % of stocks to strategic investors (at present 100 % of stocks belongs to state). Authors of the article regard, that the Kazakhstan's uranium industry still has significant reserves to develop. Even if the scenario for the uranium industry could be unfavorable, uranium production in Kazakhstan may triple within the next three to four years. The processing of uranium by the Ulbinskij Metallurgical Plant and the production of some by-products, such as rhenium, vanadium and rare-earth elements, may provide more profits. Obviously, the sale of uranium (as well as of any other reserves) cannot make Kazakhstan a prosperous country. However, country's uranium industry has a god chance to become one of the most important and advanced sectors of national economy

Controlling factors of uranium mineralization and prospect prediction in Qimantage area

International Nuclear Information System (INIS)

Yao Chunling; Zhu Pengfei; Cai Yuqi; Zhang Wenming; Zhao Yong'an; Song Jiye; Zhang Xiaojin

2011-01-01

Based on the analysis of regional geology in Qimantage area, the condition for uranium mineralization is summarized in regional geology setting, volcanic, granite and faults. This study shows that this area has favorable prospect for uranium mineralization. The metallogenic model is built up according to the controlling factors over uranium mineralization. Under this model, six potential areas are predicted in MRAS software with mineralization factors of synthetically geological information method. (authors)

Experimental study and numerical modelling of geochemical reactions occurring during uranium in situ recovery (ISR) mining

International Nuclear Information System (INIS)

Ben Simon, R.

2011-09-01

The in situ Recovery (ISR) method consists of ore mining by in situ chemical leaching with acid or alkaline solutions. ISR takes place underground and is therefore limited to the analysis of the pumped solutions, hence ISR mine management is still empirical. Numerical modelling has been considered to achieve more efficient management of this process. Three different phenomena have to be taken into account for numerical simulations of uranium ISR mining: (1) geochemical reactions; (2) the kinetics of these reactions, and (3) hydrodynamic transport with respect to the reaction kinetics. Leaching tests have been conducted on ore samples from an uranium mine in Tortkuduk (Kazakhstan) where ISR is conducted by acid leaching. Two types of leaching experiments were performed: (1) tests in batch reactors; and (2) extraction in flow through columns. The assumptions deduced from the leaching tests were tested and validated by modelling the laboratory experiments with the numerical codes CHESS and HYTEC, both developed at the Geosciences research center of Mines ParisTech. A well-constrained 1D hydrogeochemical transport model of the ISR process at laboratory-scale was proposed. It enables to translate the chemical release sequence that is observed during experiments into a geochemical reaction sequence. It was possible to highlight the controlling factors of uranium dissolution, and the precipitation of secondary mineral phase in the deposit, as well as the determination of the relative importance of these factors. (author)

Studying uranium migration in natural environment: experimental approach and geochemical modeling; Etude de la migration de l'uranium en milieu naturel: approche experimentale et modelisation geochimique

Energy Technology Data Exchange (ETDEWEB)

Phrommavanh, V.

2008-10-15

The present study deals with characterizing uranium migration in a limited zone of Le Bouchet site, a former uranium ore treatment facility, which is dismantled and the rehabilitation of which is under process. Some wastes are packed in a rehabilitated disposal nearby, called the Itteville site. In the framework of the monitoring of the deposit environment (air, water, sediment) set by prefectorial decrees, a piezometer (PZPK) located downstream to the latter, has shown total dissolved uranium peaks each winter since the 1990's. PZPK collects both the interstitial water of a calcareous peat formation, between the surface and 3 m, and an alluvial aquifer near 6 m of depth. Firstly, a hydrogeochemical characterization of the site has evidenced the uranium source term, which is present in the peat soil near 0.8 m, hence excluding any leaching from the waste disposal. Actually, a few microparticles of uranium oxide and mixed uranium-thorium oxide have been detected, but they do not represent the major part of the source term. Secondly, water chemistry of the peat soil water and PZPK has been monitored every two months from 2004 to 2007 in order to understand the reasons of the seasonal fluctuations of [U]tot.diss.. Completed with geochemical modeling and a bacterial identification by 16S rDNA sequence analysis, water chemistry data showed an important sulfate-reducing bacterial activity in summertime, leading to reducing conditions and therefore, a total dissolved uranium content limited by the low solubility of uraninite U{sup IV}O{sub 2}(s). In wintertime, the latter bacterial activity being minimal and the effective pluviometry more important, conditions are more oxidant, which favors U(VI), more soluble, notably as the Ca{sub 2}UO{sub 2}(CO{sub 3}){sub 3}(aq) complex, evidenced by TRLFS. Finally, bacterial activity has been reproduced in laboratory in order to better characterize its impact on uranium solubility in the peat soil. Various parameters were tested

Uranium enrichment plans

International Nuclear Information System (INIS)

Gagne, R.W.; Thomas, D.C.

1977-01-01

The status of existing uranium enrichment contracts in the US is reviewed and expected natural uranium requirements for existing domestic uranium enrichment contracts are evaluated. Uncertainty in natural uranium requirements associated with requirements-type and fixed-commitment type contracts is discussed along with implementation of variable tails assay

Spatial analysis techniques applied to uranium prospecting in Chihuahua State, Mexico

Science.gov (United States)

Hinojosa de la Garza, Octavio R.; Montero Cabrera, María Elena; Sanín, Luz H.; Reyes Cortés, Manuel; Martínez Meyer, Enrique

2014-07-01

To estimate the distribution of uranium minerals in Chihuahua, the advanced statistical model "Maximun Entropy Method" (MaxEnt) was applied. A distinguishing feature of this method is that it can fit more complex models in case of small datasets (x and y data), as is the location of uranium ores in the State of Chihuahua. For georeferencing uranium ores, a database from the United States Geological Survey and workgroup of experts in Mexico was used. The main contribution of this paper is the proposal of maximum entropy techniques to obtain the mineral's potential distribution. For this model were used 24 environmental layers like topography, gravimetry, climate (worldclim), soil properties and others that were useful to project the uranium's distribution across the study area. For the validation of the places predicted by the model, comparisons were done with other research of the Mexican Service of Geological Survey, with direct exploration of specific areas and by talks with former exploration workers of the enterprise "Uranio de Mexico". Results. New uranium areas predicted by the model were validated, finding some relationship between the model predictions and geological faults. Conclusions. Modeling by spatial analysis provides additional information to the energy and mineral resources sectors.

Uranium speciation in plants

International Nuclear Information System (INIS)

Guenther, A.; Bernhard, G.; Geipel, G.; Reich, T.; Rossberg, A.; Nitsche, H.

2003-01-01

Detailed knowledge of the nature of uranium complexes formed after the uptake by plants is an essential prerequisite to describe the migration behavior of uranium in the environment. This study focuses on the determination of uranium speciation after uptake of uranium by lupine plants. For the first time, time-resolved laser-induced fluorescence spectroscopy and X-ray absorption spectroscopy were used to determine the chemical speciation of uranium in plants. Differences were detected between the uranium speciation in the initial solution (hydroponic solution and pore water of soil) and inside the lupine plants. The oxidation state of uranium did not change and remained hexavalent after it was taken up by the lupine plants. The chemical speciation of uranium was identical in the roots, shoot axis, and leaves and was independent of the uranium speciation in the uptake solution. The results indicate that the uranium is predominantly bound as uranyl(VI) phosphate to the phosphoryl groups. Dandelions and lamb's lettuce showed uranium speciation identical to lupine plants. (orig.)

Bulk division of metallogenetic region and uranium metallogenetic regularities in Heilongjiang basin and its adjacent areas

International Nuclear Information System (INIS)

Guo Hua; Zhao Fengmin; Hu Shaokang; Chen Zuyi

2002-01-01

On the base of the study in the working area, a conclusion is made that there are 36 combined types of tectonic-material and 6 basic tectonic units. According to radioactive geochemical quantitative and qualitative factors, which are relevant to rock composition and geological formation, 5 radioactive geochemical provinces and 8 radioactive geochemical differentiation regions could be marked out. The working area contains three hydrogeological fold belts and two hydrogeological artesian basins. It could also be divided into 9 metallogenetic provinces or 30 metallogenetic regions, or 206 ore districts. On the other hand, the area could be divided into 2 uranium metallogenetic provinces, 2 potential uranium metallogenetic provinces and 3 uraniferous provinces, which contain uranium properties or potential uranium properties or uraniferous properties. The authors systematically summary the geological environment and indicators of prospecting and predicting of fluorine-molybdenum-uranium formation, hydromorphic uranium deposit formation and poly-genetic uranium deposit formation which contains uranium-coal model, uranium-asphalt model, uranium-sulfuret model, etc. The metallogenetic potential among Aerdan uranium province, Aoliaokema uranium province, Bulieya-Jiamusi-Xingkai potential uranium province and Xihuote-Alin uranium province are assessed. On this base, the authors delineate 23 uranium metallogenetic prospective areas needing further exploration efforts. 8 uranium metallogenetic prospective areas in China are marked out, which are areas of interest for searching for exogenetic and epigenetic sandstone uranium deposits

Uranium mining in Canada and Australia

International Nuclear Information System (INIS)

Mackenzie, B.W.; Whillans, R.T.; Williams, R.M.; Doggett, M.D.

1991-01-01

This study compared the impact of taxation on the economic viability and competitive position of uranium mining in Canada and Australia. The evaluation is based on four types of uranium deposit and four hypothetical project models. The deposits are assumed to have been discovered and delineated, and are awaiting a mine development decision. The models, initially appraised on a before-tax basis, are then subjected to taxation in each of six jurisdictions. Several taxation criteria are assessed in each case, including after-tax measures of investment incentive, discounted tax revenues, effective tax rates, intergovernmental tax shares, and comparative tax levels. The impact of taxation is shown to be both high and variable. The taxation systems in Saskatchewan and Australia's Northern Territory generate the most government revenue and provide the lowest incentive for investment. Canada's Northwest Territories and Ontario provide the best investment incentive and collect the least amount of taxes. South Australia and Western Australia tend to be positioned between these extremes. The study demonstrates that only the very best uranium mining projects have a chance of being developed under current market conditions, and even these can be rendered uneconomic by excessive taxation regimes. It follows that exceptionally good quality targets will have to be identified to provide the economic justification for uranium exploration. These realities will likely restrict uranium exploration and development activities for some time, not an unexpected response to a market situation where low prices have been caused largely by excess supply. (L.L.)

Uranium recovering from slags generated in the metallic uranium by magnesiothermic reduction

International Nuclear Information System (INIS)

Fornarolo, F.; Carvalho, E.F. Urano de; Durazzo, M.; Riella, H.G.

2008-01-01

The Nuclear Fuel Center of IPEN/CNEN-SP has recent/y concluded a program for developing the fabrication technology of the nuclear fuel based on the U 3 Si 2 -Al dispersion, which is being used in the IEA-R1 research reactor. The uranium silicide (U 3 Si 2 ) fuel production starts with the uranium hexafluoride (UF 6 ) processing and uranium tetrafluoride (UF 4 ) precipitation. Then, the UF 4 is converted to metallic uranium by magnesiothermic reduction. The UF 4 reduction by magnesium generates MgF 2 slag containing considerable concentrations of uranium, which could reach 20 wt%. The uranium contained in that slag should be recovered and this work presents the results obtained in recovering the uranium from that slag. The uranium recovery is accomplished by acidic leaching of the calcined slag. The calcination transforms the metallic uranium in U 3 O 8 , promoting the pulverization of the pieces of metallic uranium and facilitating the leaching operation. As process variables, have been considered the nitric molar concentration, the acid excess regarding the stoichiometry and the leaching temperature. As result, the uranium recovery reached a 96% yield. (author)

Process for producing uranium oxide rich compositions from uranium hexafluoride

International Nuclear Information System (INIS)

DeHollander, W.R.; Fenimore, C.P.

1978-01-01

Conversion of gaseous uranium hexafluoride to a uranium dioxide rich composition in the presence of an active flame in a reactor defining a reaction zone is achieved by separately introducing a first gaseous reactant comprising a mixture of uranium hexafluoride and a reducing carrier gas, and a second gaseous reactant comprising an oxygen-containing gas. The reactants are separated by a shielding gas as they are introduced to the reaction zone. The shielding gas temporarily separates the gaseous reactants and temporarily prevents substantial mixing and reacting of the gaseous reactants. The flame occurring in the reaction zone is maintained away from contact with the inlet introducing the mixture to the reaction zone. After suitable treatment, the uranium dioxide rich composition is capable of being fabricated into bodies of desired configuration for loading into nuclear fuel rods. Alternatively, an oxygen-containing gas as a third gaseous reactant is introduced when the uranium hexafluoride conversion to the uranium dioxide rich composition is substantially complete. This results in oxidizing the uranium dioxide rich composition to a higher oxide of uranium with conversion of any residual reducing gas to its oxidized form

Lead as a pathfinder for uranium mineralization

International Nuclear Information System (INIS)

Shouls, M.M.

1983-01-01

The theoretical aspects of the formation of radiogenic lead anomalies from uranium and thorium mineralization are discussed in the light of differing mobilities of the parent elements and the stable lead daughter. It is concluded that recognizable lead anomalies can persist in the weathered tops of ancient uranium deposits, and such anomalies can be identified from the stable lead isotope ratios. In addition, with mixed U-Th mineralization lead isotopic ratios may be identified after most of the uranium has been leached away. The theoretical models also include possible additions of entrained lead with the mineralization and its effects on the isotopic ratios. This reasoning was tested in the evaluation of a radiometric anomaly in northern Malawi where a discrepancy between the U and eU values suggested a uranium-depleted mixed U-Th deposit. However, the partly coincident lead anomaly did not fit the isotope models proposed in the first part of the paper, and they indicated an unexpectedly young age. The anomaly was therefore downgraded but the adequacy of the theory was not tested. (author)

Formation conditions of uranium minerals in oxidation zone of uranium deposits

International Nuclear Information System (INIS)

Li Youzhu

2005-01-01

The paper concerns about the summary and classification of hydrothermal uranium deposit with oxidation zone. Based on the summary of observation results of forty uranium deposits located in CIS and Bulgaria which are of different sizes and industrial-genetic types, analysis on available published information concerning oxidation and uranium mineral enrichment in supergenic zone, oxidation zone classification of hydrothermal uranium had been put forward according to the general system of the exogenetic uranium concentration. (authors)

Uranium industry annual 1994

International Nuclear Information System (INIS)

1995-01-01

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

Inhalation hazards to uranium miners

International Nuclear Information System (INIS)

Cross, F.T.

1982-01-01

This project is investigating levels of uranium mine air contaminants, using both large and small experimental animals to model human respiratory system disease. Lung cancer and deaths by degenerative lung disease have reached epidemic proportions among uranium miners, but the cause-effect relationships for these diseases are based on inadequate epidemiological data. This project identifies agents or combinations of agents (both chemical and radiological) and their exposure levels that produce respiratory tract lesions, including respiratory epithelial carcinoma, pneumonconiosis and emphysema

Inhalation hazards to uranium miners

International Nuclear Information System (INIS)

Cross, F.T.

1983-01-01

This project is investigating levels or uranium mine air contaminants, using both large and small experimental animals to model human respiratory system disease. Lung cancer and deaths by degenerative lung disease have reached epidemic proportions among uranium miners, but the cause-effect relationships for these diseases are based on inadequate epidemiological data. This project identifies agents or combinations of agents (both chemical and radiological), and their exposure levels, that produce respiratory tract lesions, including respiratory epithelial carcinoma, pneumoconiosis, and emphysema

Short-term uranium price formation: a methodology

International Nuclear Information System (INIS)

Hsieh, L.Y.; de Graffenried, C.L.

1987-01-01

One of the major problems in analyzing the short-term uranium market is the lack of a well-defined spot market price. The two primary sources of price data covering the US uranium market are the series published by the US Dept. of Energy (DOE) and by the Nuclear Exchange Corporation (NUEXCO), a private brokerage firm. Because of the differences in both definition and coverage, these two series are not directly comparable. In this study, an econometric model was developed for analyzing the interrelationship between short-term uranium price (NUEXCO exchange value), supply, demand, and future price expectations formed by market participants. The validity of this model has been demonstrated by the fact that all simulation statistics derived are highly significant. Three forecasting scenarios were developed in this study

Biosorption of uranium and lead by Streptomyces longwoodensis

International Nuclear Information System (INIS)

Friis, N.; Myers-Keith, P.

1986-01-01

Biosorption of uranium and lead by lyophilized cells of Streptomyces longwoodensis was examined as a function of metal concentration, pH, cell concentration, and culture age. Cells harvested from the stationary growth phase exhibited an exceptionally high capacity for uranium (0.44 g U/g dry weight) at pH 5. Calculated values of the distribution coefficient and separation factor indicated a strong preference of the cell mass for uranyl ions over lead ions. The specific uranium uptake was similar for the cell wall and the cytoplasmic fraction. Uranium uptake was associated with an increase in hydrogen ion concentration, and phosphorus analysis of whole cells indicated a simple stoichiometric ratio between uranium uptake and phosphorus content. It is proposed that metal ions are bound to phosphodiester residues present both in the cell wall and cytoplasmic fractions. Based on this model, it was shown that uranium accumulation exhibits a maximum at pH 4.6 that is supported by experimental data from previous investigations

Research on geochronology and uranium source of sandstone-hosted uranium ore-formation in major uranium-productive basins, Northern-China

International Nuclear Information System (INIS)

Xia Yuliang; Liu Hanbin; Lin Jinrong; Fan Guang; Hou Yanxian

2004-12-01

A method is developed for correcting uranium content in uranium ore samples by considering the U-Ra equilibrium coefficient, then a U-Pb isochron is drawn up. By performing the above correction ore-formation ages of sandstone-hosted uranium mineralization which may be more realistic have been obtained. The comparative research on U-Pb isotopic ages of detritic zircon in ore-hosting sandstone and zircon in intermediate-acid igneous rocks in corresponding provenance area indicates that the ore-hosting sandstone is originated from the erosion of intermediate-acid igneous rocks and the latters are the material basis for the formation of the uranium-rich sandstone beds. On the basis of the study on U-Pb isotopic system evolution of the provenance rocks and sandstones from ore-hosting series, it is verified that the uranium sources of the sandstone-hosted uranium deposit are: the intermediate-acid igneous rocks with high content of mobile uranium, and the sandstone bodies pre-concentrated uranium. (authors)

Control of uranium hazards - Portsmouth uranium enrichment plant

International Nuclear Information System (INIS)

Wagner, E.R.

1985-01-01

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

Hydrogen isotope storage behavior of Zr1-xTixCo alloys

International Nuclear Information System (INIS)

Jat, Ram Avtar; Pati, Subhasis; Parida, S.C.; Agarwal, Renu; Mukerjee, S.K.

2016-01-01

Tritium storage properties similar to uranium make ZrCo as a suitable candidate material for storage, supply and recovery of hydrogen isotopes in various tritium facilities. Beside non-radioactive, nonpyrophoric at room temperature and higher storage capacity (H/f.u. up to 3, f.u. = ZrCo), it has been reported that upon repeated hydriding-dehydriding cycles, ZrCo undergoes dis-proportionation as per the reaction; ZrCo + H 2 ↔ ZrH 2 + ZrCo 2 . The present study is aimed to investigate the effect of Ti content on the hydrogen storage behavior of Zr 1-x Ti x Co alloys and the hydrogen isotope effect

Uranium industry annual, 1986

International Nuclear Information System (INIS)

1987-01-01

Uranium industry data collected in the EIA-858 survey provide a comprehensive statistical characterization of annual activities of the industry and include some information about industry plans over the next several years. This report consists of two major sections. The first addresses uranium raw materials activities and covers the following topics: exploration activities and expenditures, resources and reserves, mine production of uranium, production of uranium concentrate, and industry employment. The second major section is concerned with the following uranium marketing activities: uranium purchase commitments, uranium prices, procurement arrangements, uranium imports and exports, enrichment services, inventories, secondary market activities utility market requirements and related topics

Uranium Industry. Annual 1984

International Nuclear Information System (INIS)

Lawrence, M.S.S.

1985-01-01

This report provides a statistical description of activities of the US uranium industry during 1984 and includes a statistical profile of the status of the industry at the end of 1984. It is based on the results of an Energy Information Administration (EIA) survey entitled ''Uranium Industry Annual Survey'' (Form EIA-858). The principal findings of the survey are summarized under two headings - Uranium Raw Materials Activities and Uranium Marketing Activities. The first heading covers exploration and development, uranium resources, mine and mill production, and employment. The second heading covers uranium deliveries and delivery commitments, uranium prices, foreign trade in uranium, inventories, and other marketing activities. 32 figs., 48 tabs

Mathematical Modeling for the Extraction of Uranium and Molybdenum with Emulsion Liquid Membrane, Including Industrial Application and Cost Evaluation of the Uranium Recovery

International Nuclear Information System (INIS)

Kris Tri Basuki

2008-01-01

Emulsion liquid membrane systems are double emulsion drops. Two immiscible phases are separated by a third phase which is immiscible with the other two phases. The liquid membrane systems were classified into two types: (1) carrier mediated mass transfer, (2) mass transfer without any reaction involved. Uranium extraction, molybdenum extraction and solvent extraction were used as purposed elements for each type of the membrane systems in the derivation of their mathematical models. Mass transfer in emulsion liquid membrane (ELM) systems has been modeled by several differential and algebraic equations. The models take into account the following : mass transfer of the solute from the bulk external phase to the external phase-membrane interface; an equilibrium reaction between the solute and the carrier to form the solute-carrier complex at the interface; mass transfer by diffusion of the solute-carrier complex in the membrane phase to the membrane-internal phase interface; another equilibrium reaction of the solute-carrier complex to release the solute at the membrane-internal phase interface into the internal phase. Models with or without the consideration of film resistances were developed and compared. The models developed in this study can predict the extraction rate through emulsion liquid membranes theoretically. All parameters required in the models can be determined before an experimental extraction run. Experimental data from literature (uranium extraction) and (molybdenum extraction and solvent extraction) were used to test the models. The agreements between the theoretical predictions and the experimental data were very good. The advantages of emulsion liquid membrane systems over traditional methods were discussed. The models developed in this research can be used directly for the design of emulsion liquid membrane systems. The results of this study represent a very significant step toward the practical applications of the emulsion liquid membrane

recovery of enriched uranium from waste solution obtained from fuel fabrication laboratories

International Nuclear Information System (INIS)

Othman, S.H.A.

2003-01-01

reversed-phase partition chromatography is shown to be a convenient and applicable method for the quantitative recovery of uranium (19.7% enriched with 235 U) from highly impure solution . the processing of uranium compounds for atomic energy project especially in FMPP(Egyptian fuel manufacture pilot plant) gives rise to a variety of wastes in which the uranium content is of considerable importance. the recovery of uranium from concentrated mother liquors produced from ADU (ammonium diuranate ) precipitation, as well as those due to ADU washing is studied in this work. column of poly-trifluoro-monochloro-ethilene (Kel-F) supporting tri-n-butyl-phosphate (TBP) retains uranium .impurities are eluted with 6.5 M HCl, and the uranium is eluted with water and the recovery of uranium is better than 94%. A mathematical model was suggested to stimulate the sorption process of uranium ions (or any other ion ) by column of solvent impregnated resin containing organic extractant (the same as the previous column) . An excellent agreement was founded between the experimental results and the mathematical model

Irradiated uranium reprocessing

International Nuclear Information System (INIS)

Gal, I.

1961-12-01

Task concerned with reprocessing of irradiated uranium covered the following activities: implementing the method and constructing the cell for uranium dissolving; implementing the procedure for extraction of uranium, plutonium and fission products from radioactive uranium solutions; studying the possibilities for using inorganic ion exchangers and adsorbers for separation of U, Pu and fission products

Uranium

International Nuclear Information System (INIS)

Anon.

1984-01-01

The article briefly discusses the Australian government policy and the attitude of political party factions towards the mining and exporting of the uranium resources in Australia. Australia has a third of the Western World's low-cost uranium resources

Mortality (1968-2008) in a French cohort of uranium enrichment workers potentially exposed to rapidly soluble uranium compounds.

Science.gov (United States)

Zhivin, Sergey; Guseva Canu, Irina; Samson, Eric; Laurent, Olivier; Grellier, James; Collomb, Philippe; Zablotska, Lydia B; Laurier, Dominique

2016-03-01

Until recently, enrichment of uranium for civil and military purposes in France was carried out by gaseous diffusion using rapidly soluble uranium compounds. We analysed the relationship between exposure to soluble uranium compounds and exposure to external γ-radiation and mortality in a cohort of 4688 French uranium enrichment workers who were employed between 1964 and 2006. Data on individual annual exposure to radiological and non-radiological hazards were collected for workers of the AREVA NC, CEA and Eurodif uranium enrichment plants from job-exposure matrixes and external dosimetry records, differentiating between natural, enriched and depleted uranium. Cause-specific mortality was compared with the French general population via standardised mortality ratios (SMR), and was analysed via Poisson regression using log-linear and linear excess relative risk models. Over the period of follow-up, 131 161 person-years at risk were accrued and 21% of the subjects had died. A strong healthy worker effect was observed: all causes SMR=0.69, 95% CI 0.65 to 0.74. SMR for pleural cancer was significantly increased (2.3, 95% CI 1.06 to 4.4), but was only based on nine cases. Internal uranium and external γ-radiation exposures were not significantly associated with any cause of mortality. This is the first study of French uranium enrichment workers. Although limited in statistical power, further follow-up of this cohort, estimation of internal uranium doses and pooling with similar cohorts should elucidate potential risks associated with exposure to soluble uranium compounds. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Uranium enrichment capacity: public versus private ownership

International Nuclear Information System (INIS)

Fraser, J.T.

1977-01-01

Continual growth of conventional nuclear capacity requires an assured supply of enriched uranium and, hence, potential expansion of domestic uranium enrichment capacity. The question of ownership of new enrichment capacity, i.e., public or private, entails not only the social-opportunity costs of alternative investments but also technical parameters of uranium utilization and advanced reactor development. Inclusion of risk preferences in both the public and private sectors produces interesting results in terms of optimal investment strategies with respect to choice of technology and scale of investment. Utilization of a nuclear fuel cycle requirements process model allows explicit specification of production technology. Integration of process model output with a least-cost investment model permits flexibility in parametric analysis. Results indicate minimum incentive for Government subsidy of a private enrichment sector through 2000 given moderate to low nuclear growth assumptions. The long-run scenario, to 2020, exhibits potentially greater incentives for private enrichment investment

Uranium industry annual 1998

International Nuclear Information System (INIS)

1999-01-01

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

Modeling Substrate Utilization, Metabolite Production, and Uranium Immobilization in Shewanella oneidensis Biofilms

Directory of Open Access Journals (Sweden)

Ryan S. Renslow

2017-06-01

Full Text Available In this study, we developed a two-dimensional mathematical model to predict substrate utilization and metabolite production rates in Shewanella oneidensis MR-1 biofilm in the presence and absence of uranium (U. In our model, lactate and fumarate are used as the electron donor and the electron acceptor, respectively. The model includes the production of extracellular polymeric substances (EPS. The EPS bound to the cell surface and distributed in the biofilm were considered bound EPS (bEPS and loosely associated EPS (laEPS, respectively. COMSOL® Multiphysics finite element analysis software was used to solve the model numerically (model file provided in the Supplementary Material. The input variables of the model were the lactate, fumarate, cell, and EPS concentrations, half saturation constant for fumarate, and diffusion coefficients of the substrates and metabolites. To estimate unknown parameters and calibrate the model, we used a custom designed biofilm reactor placed inside a nuclear magnetic resonance (NMR microimaging and spectroscopy system and measured substrate utilization and metabolite production rates. From these data we estimated the yield coefficients, maximum substrate utilization rate, half saturation constant for lactate, stoichiometric ratio of fumarate and acetate to lactate and stoichiometric ratio of succinate to fumarate. These parameters are critical to predicting the activity of biofilms and are not available in the literature. Lastly, the model was used to predict uranium immobilization in S. oneidensis MR-1 biofilms by considering reduction and adsorption processes in the cells and in the EPS. We found that the majority of immobilization was due to cells, and that EPS was less efficient at immobilizing U. Furthermore, most of the immobilization occurred within the top 10 μm of the biofilm. To the best of our knowledge, this research is one of the first biofilm immobilization mathematical models based on experimental

A coupled transport and solid mechanics formulation with improved reaction kinetics parameters for modeling oxidation and decomposition in a uranium hydride bed.

Energy Technology Data Exchange (ETDEWEB)

Salloum, Maher N.; Shugard, Andrew D.; Kanouff, Michael P.; Gharagozloo, Patricia E.

2013-03-01

Modeling of reacting flows in porous media has become particularly important with the increased interest in hydrogen solid-storage beds. An advanced type of storage bed has been proposed that utilizes oxidation of uranium hydride to heat and decompose the hydride, releasing the hydrogen. To reduce the cost and time required to develop these systems experimentally, a valid computational model is required that simulates the reaction of uranium hydride and oxygen gas in a hydrogen storage bed using multiphysics finite element modeling. This SAND report discusses the advancements made in FY12 (since our last SAND report SAND2011-6939) to the model developed as a part of an ASC-P&EM project to address the shortcomings of the previous model. The model considers chemical reactions, heat transport, and mass transport within a hydride bed. Previously, the time-varying permeability and porosity were considered uniform. This led to discrepancies between the simulated results and experimental measurements. In this work, the effects of non-uniform changes in permeability and porosity due to phase and thermal expansion are accounted for. These expansions result in mechanical stresses that lead to bed deformation. To describe this, a simplified solid mechanics model for the local variation of permeability and porosity as a function of the local bed deformation is developed. By using this solid mechanics model, the agreement between our reacting bed model and the experimental data is improved. Additionally, more accurate uranium hydride oxidation kinetics parameters are obtained by fitting the experimental results from a pure uranium hydride oxidation measurement to the ones obtained from the coupled transport-solid mechanics model. Finally, the coupled transport-solid mechanics model governing equations and boundary conditions are summarized and recommendations are made for further development of ARIA and other Sandia codes in order for them to sufficiently implement the model.

Preparation of uranium-230 as a new uranium tracer

International Nuclear Information System (INIS)

Hashimoto, T.; Kido, K.; Sotobayashi, T.

1977-01-01

A uranium isotope, 230 U(T=20.8 d), was produced from the 231 Pa(γ,n) 230 Pa→viaβ - decay 230 U process with a bremsstrahlung irradiation on a protactinium target. After standing for about one month to obtain a maximal growth of 230 U, the uranium was chemically purified, applying an ion-exchange method. The purity of the 230 U obtained was examined with alpha spectrometry and an intrinsic alpha peak due to 230 U as a new uranium tracer in an alpha spectrometric analysis of uranium isotopes is described. (author)

Synthesis of Uranium nitride powders using metal uranium powders

International Nuclear Information System (INIS)

Yang, Jae Ho; Kim, Dong Joo; Oh, Jang Soo; Rhee, Young Woo; Kim, Jong Hun; Kim, Keon Sik

2012-01-01

Uranium nitride (UN) is a potential fuel material for advanced nuclear reactors because of their high fuel density, high thermal conductivity, high melting temperature, and considerable breeding capability in LWRs. Uranium nitride powders can be fabricated by a carbothermic reduction of the oxide powders, or the nitriding of metal uranium. The carbothermic reduction has an advantage in the production of fine powders. However it has many drawbacks such as an inevitable engagement of impurities, process burden, and difficulties in reusing of expensive N 15 gas. Manufacturing concerns issued in the carbothermic reduction process can be solved by changing the starting materials from oxide powder to metals. However, in nitriding process of metal, it is difficult to obtain fine nitride powders because metal uranium is usually fabricated in the form of bulk ingots. In this study, a simple reaction method was tested to fabricate uranium nitride powders directly from uranium metal powders. We fabricated uranium metal spherical powder and flake using a centrifugal atomization method. The nitride powders were obtained by thermal treating those metal particles under nitrogen containing gas. We investigated the phase and morphology evolutions of powders during the nitriding process. A phase analysis of nitride powders was also a part of the present work

Uranium geochemistry in soil and groundwater at the F and H seepage basins

International Nuclear Information System (INIS)

Serkiz, S.M.; Johnson, W.H.

1994-09-01

For 33 years, low activity liquid wastes from the chemical separation areas at the U.S. Department of Energy's Savannah River Site were disposed of in unlined seepage basins. Soil and associated pore water samples of widely varying groundwater chemistries and contaminant concentrations were collected from the region downgradient of these basins using cone penetrometer technology. Analysis of samples using inductively coupled plasma - mass spectrometry has allowed the investigation of uranium partitioning between the aqueous phase and soil surfaces at this site. The distribution of uranium was examined with respect to the solution and soil chemistry (e.g., pH, redox potential, cation and contaminant concentration) and aqueous-phase chemical speciation modeling. The uranium soil source term at the F- and H-Area Seepage Basins (FHSB) is much smaller than has been used in previous modeling efforts. This should result in a much shorter remediation time and a greater effectiveness of a pump-and-treat design than previously predicted. Distribution coefficients at the (FHSB) were found to vary between 1.2 to 34,000 1 kg -1 for uranium. Differences in sorption of these elements can be explained primarily by changes in aqueous pH and the associated change in soil surface charge. Sorption models were fit directly to sorption isotherms from field samples. All models underestimated the fraction of uranium bound at low aqueous uranium concentrations. Linear models overestimated bound uranium at locations where the aqueous concentration was greater than 500 ppb. Mechanistic models provided a much better estimate of the bound uranium concentrations, especially at high aqueous concentrations. Since a large fraction of the uranium at the site is associated with the low-pH portion of the plume, consideration should be given to pumping water from the lowest pH portions of the plume in the F-Area

Uranium uptake history, open-system behaviour and uranium-series ages of fossil Tridacna gigas from Huon Peninsula, Papua New Guinea

Science.gov (United States)

Ayling, Bridget F.; Eggins, Stephen; McCulloch, Malcolm T.; Chappell, John; Grün, Rainer; Mortimer, Graham

2017-09-01

Molluscs incorporate negligible uranium into their skeleton while they are living, with any uranium uptake occurring post-mortem. As such, closed-system U-series dating of molluscs is unlikely to provide reliable age constraints for marine deposits. Even the application of open-system U-series modelling is challenging, because uranium uptake and loss histories can affect time-integrated uranium distributions and are difficult to constrain. We investigate the chemical and isotopic distribution of uranium in fossil Tridacna gigas (giant clams) from Marine Isotope Stage (MIS) 5e (128-116 ka) and MIS 11 (424-374 ka) reefs at Huon Peninsula in Papua New Guinea. The large size of the clams enables detailed chemical and isotopic mapping of uranium using LA-ICPMS and LA-MC-ICPMS techniques. Within each fossil Tridacna specimen, marked differences in uranium concentrations are observed across the three Tridacna growth zones (outer, inner, hinge), with the outer and hinge zones being relatively enriched. In MIS 5e and MIS 11 Tridacna, the outer and hinge zones contain approximately 1 ppm and 5 ppm uranium respectively. In addition to uptake of uranium, loss of uranium appears prevalent, especially in the MIS 11 specimens. The effect of uranium loss is to elevate measured [230Th/238U] values with little effect on [234U/238U] values. Closed-system age estimates are on average 50% too young for the MIS 5e Tridacna, and 25% too young for the MIS 11 Tridacna. A complex, multi-stage uptake and loss history is interpreted for the fossil Tridacna and we demonstrate that they cannot provide independent, reliable geochronological controls on the timing of past reef growth at Huon Peninsula.

A coupled mass transfer and surface complexation model for uranium (VI) removal from wastewaters

International Nuclear Information System (INIS)

Lenhart, J.; Figueroa, L.A.; Honeyman, B.D.

1994-01-01

A remediation technique has been developed for removing uranium (VI) from complex contaminated groundwater using flake chitin as a biosorbent in batch and continuous flow configurations. With this system, U(VI) removal efficiency can be predicted using a model that integrates surface complexation models, mass transport limitations and sorption kinetics. This integration allows the reactor model to predict removal efficiencies for complex groundwaters with variable U(VI) concentrations and other constituents. The system has been validated using laboratory-derived kinetic data in batch and CSTR systems to verify the model predictions of U(VI) uptake from simulated contaminated groundwater

Uranium market

International Nuclear Information System (INIS)

Rubini, L.A.; Asem, M.A.D.

1990-01-01

The historical development of the uranium market is present in two periods: The initial period 1947-1970 and from 1970 onwards, with the establishment of a commercial market. The world uranium requirements are derived from the corresponding forecast of nuclear generating capacity, with, particular emphasis to the brazilian requirements. The forecast of uranium production until the year 2000 is presented considering existing inventories and the already committed demand. The balance between production and requirements is analysed. Finally the types of contracts currently being used and the development of uranium prices in the world market are considered. (author)

Debye temperatures of uranium chalcogenides from their lattice ...

Indian Academy of Sciences (India)

Phonon dispersion relations in uranium chalcogenides have been investigated using a modified three-body force shell model. From the phonon frequencies, their Debye temperatures are evaluated. Further, on the basis of the spin fluctuation in the heavy fermion uranium compounds, UPt3 and UBe13, the possible ...

First-principles study on oxidation effects in uranium oxides and high-pressure high-temperature behavior of point defects in uranium dioxide

Science.gov (United States)

Geng, Hua Y.; Song, Hong X.; Jin, K.; Xiang, S. K.; Wu, Q.

2011-11-01

Formation Gibbs free energy of point defects and oxygen clusters in uranium dioxide at high-pressure high-temperature conditions are calculated from first principles, using the LSDA+U approach for the electronic structure and the Debye model for the lattice vibrations. The phonon contribution on Frenkel pairs is found to be notable, whereas it is negligible for the Schottky defect. Hydrostatic compression changes the formation energies drastically, making defect concentrations depend more sensitively on pressure. Calculations show that, if no oxygen clusters are considered, uranium vacancy becomes predominant in overstoichiometric UO2 with the aid of the contribution from lattice vibrations, while compression favors oxygen defects and suppresses uranium vacancy greatly. At ambient pressure, however, the experimental observation of predominant oxygen defects in this regime can be reproduced only in a form of cuboctahedral clusters, underlining the importance of defect clustering in UO2+x. Making use of the point defect model, an equation of state for nonstoichiometric oxides is established, which is then applied to describe the shock Hugoniot of UO2+x. Furthermore, the oxidization and compression behavior of uranium monoxide, triuranium octoxide, uranium trioxide, and a series of defective UO2 at 0 K are investigated. The evolution of mechanical properties and electronic structures with an increase of the oxidation degree are analyzed, revealing the transition of the ground state of uranium oxides from metallic to Mott insulator and then to charge-transfer insulator due to the interplay of strongly correlated effects of 5f orbitals and the shift of electrons from uranium to oxygen atoms.

Sustainability of uranium sources

International Nuclear Information System (INIS)

Prasser, Horst-Michael; Bayard, Andre-Samuel; Dones, Roberto

2008-01-01

Smith and Storm van Leeuwen (SSL, 2005) point out that the growth of the energy requirements for uranium mining and milling at decreasing ore grades will cause the output of the nuclear energy chain to become negative at uranium contents in the ore below 100 - 200 ppm. They conclude that an expiration of uranium will occur by 2076 in a business-as-usual scenario and by about 2050 when a 2.5 % annual growth of the consumption is assumed. The high relevance of this issue is the motivation for a detailed review of these results. The concept of a limiting ore grade was introduced by Chapman already in 1975. His model has been fitted to the performance data of the Roessing mine in Namibia operating at low grade, which makes further extrapolations more reliable. The performance data published in open literature allows quantifying the energy requirements for the removal of the waste rock separately from those for the mining of the ore, which is one of the concepts of Chapman. It is shown that the amount of waste rock to be removed per unit ore has a strong effect on the energy consumed in the mine. The limiting ore grade is much lower than the one predicted by SSL and much higher amounts of uranium are predicted for a continuation of the utilization of nuclear power. Despite of the fact that SSL cite the paper of Chapman (1975), they decide to develop an own oversimplified model based on a reciprocal proportionality of the energy requirements to the ore grade alone, which is a significant step back. SSL even cite a statement of Chapman directly, saying that the stripping ratio can influence the energy requirements of uranium mining 'by a factor of five', without drawing the right conclusions. Furthermore, neither a comparison to more recent mine data, nor any kind of an uncertainty analysis is presented. The approach of SSL must therefore be disqualified as unscientific and their results discarded. (authors)

Sustainability of uranium sources

Energy Technology Data Exchange (ETDEWEB)

Prasser, Horst-Michael; Bayard, Andre-Samuel [ETH Zurich, 8092 Zurich (Switzerland); Dones, Roberto [Paul Scherrer Institute, 5232 Villigen (Switzerland)

2008-07-01

Smith and Storm van Leeuwen (SSL, 2005) point out that the growth of the energy requirements for uranium mining and milling at decreasing ore grades will cause the output of the nuclear energy chain to become negative at uranium contents in the ore below 100 - 200 ppm. They conclude that an expiration of uranium will occur by 2076 in a business-as-usual scenario and by about 2050 when a 2.5 % annual growth of the consumption is assumed. The high relevance of this issue is the motivation for a detailed review of these results. The concept of a limiting ore grade was introduced by Chapman already in 1975. His model has been fitted to the performance data of the Roessing mine in Namibia operating at low grade, which makes further extrapolations more reliable. The performance data published in open literature allows quantifying the energy requirements for the removal of the waste rock separately from those for the mining of the ore, which is one of the concepts of Chapman. It is shown that the amount of waste rock to be removed per unit ore has a strong effect on the energy consumed in the mine. The limiting ore grade is much lower than the one predicted by SSL and much higher amounts of uranium are predicted for a continuation of the utilization of nuclear power. Despite of the fact that SSL cite the paper of Chapman (1975), they decide to develop an own oversimplified model based on a reciprocal proportionality of the energy requirements to the ore grade alone, which is a significant step back. SSL even cite a statement of Chapman directly, saying that the stripping ratio can influence the energy requirements of uranium mining 'by a factor of five', without drawing the right conclusions. Furthermore, neither a comparison to more recent mine data, nor any kind of an uncertainty analysis is presented. The approach of SSL must therefore be disqualified as unscientific and their results discarded. (authors)

Uranium from Seawater Program Review; Fuel Resources Uranium from Seawater Program DOE Office of Nuclear Energy

Energy Technology Data Exchange (ETDEWEB)

None

2013-07-01

the rate-limiting step of uranium uptake from seawater is also essential in designing an effective uranium recovery system. Finally, economic analyses have been used to guide these studies and highlight what parameters, such as capacity, recyclability, and stability, have the largest impact on the cost of extraction of uranium from seawater. Initially, the cost estimates by the JAEA for extraction of uranium from seawater with braided polymeric fibers functionalized with amidoxime ligands were evaluated and updated. The economic analyses were subsequently updated to reflect the results of this project while providing insight for cost reductions in the adsorbent development through “cradle-to-grave” case studies for the extraction process. This report highlights the progress made over the last three years on the design, synthesis, and testing of new materials to extract uranium for seawater. This report is organized into sections that highlight the major research activities in this project: (1) Chelate Design and Modeling, (2) Thermodynamics, Kinetics and Structure, (3) Advanced Polymeric Adsorbents by Radiation Induced Grafting, (4) Advanced Nanomaterial Adsorbents, (5) Adsorbent Screening and Modeling, (6) Marine Testing, and (7) Cost and Energy Assessment. At the end of each section, future research directions are briefly discussed to highlight the challenges that still remain to reduce the cost of extractions of uranium for seawater. Finally, contributions from the Nuclear Energy University Programs (NEUP), which complement this research program, are included at the end of this report.

Water balance modelling of a uranium mill effluent management system

Science.gov (United States)

Plagnes, Valérie; Schmid, Brad; Mitchell, Brett; Judd-Henrey, Ian

2017-06-01

A water balance model was developed to forecast the management strategy of a uranium mill effluent system, located in northern Saskatchewan, Canada. Mining and milling operations, such as pit dewatering or treated effluent release, can potentially influence the hydrology and the water quality downstream of the operations. This study presents the methodology used to predict water volumes and water quality discharging downstream in surface water bodies. A compartment model representing the three subsequent lakes included in the management system was set up using the software GoldSim®. The water balance allows predicting lake volumes at the daily time step. A mass balance model developed for conservative elements was also developed and allows validating the proportions of inputs and outputs issued from the water balance model. This model was then used as predictive tool to evaluate the impact of different scenarios of effluents management on volumes and chemistry of surface water for short and longer time periods. An additional significant benefit of this model is that it can be used as an input for geochemical modelling to predict the concentrations of all constituents of concern in the receiving surface water.

National Uranium Resource Evaluation. Volume 1. Summary of the geology and uranium potential of Precambrian conglomerates in southeastern Wyoming

Energy Technology Data Exchange (ETDEWEB)

Karlstrom, K.E.; Houston, R.S.; Flurkey, A.J.; Coolidge, C.M.; Kratochvil, A.L.; Sever, C.K.

1981-02-01

A series of uranium-, thorium-, and gold-bearing conglomerates in Late Archean and Early Proterozoic metasedimentary rocks have been discovered in southern Wyoming. The mineral deposits were found by applying the time and strata bound model for the origin of uranium-bearing quartz-pebble conglomerates to favorable rock types within a geologic terrane known from prior regional mapping. No mineral deposits have been discovered that are of current (1981) economic interest, but preliminary resource estimates indicate that over 3418 tons of uranium and over 1996 tons of thorium are present in the Medicine Bow Mountains and that over 440 tons of uranium and 6350 tons of thorium are present in Sierra Madre. Sampling has been inadequate to determine gold resources. High grade uranium deposits have not been detected by work to date but local beds of uranium-bearing conglomerate contain as much as 1380 ppM uranium over a thickness of 0.65 meters. This project has involved geologic mapping at scales from 1/6000 to 1/50,000 detailed sampling, and the evaluation of 48 diamond drill holes, but the area is too large to fully establish the economic potential with the present information. This first volume summarizes the geologic setting and geologic and geochemical characteristics of the uranium-bearing conglomerates. Volume 2 contains supporting geochemical data, lithologic logs from 48 drill holes in Precambrian rocks, and drill site geologic maps and cross-sections from most of the holes. Volume 3 is a geostatistical resource estimate of uranium and thorium in quartz-pebble conglomerates.

National Uranium Resource Evaluation. Volume 1. Summary of the geology and uranium potential of Precambrian conglomerates in southeastern Wyoming

International Nuclear Information System (INIS)

Karlstrom, K.E.; Houston, R.S.; Flurkey, A.J.; Coolidge, C.M.; Kratochvil, A.L.; Sever, C.K.

1981-02-01

A series of uranium-, thorium-, and gold-bearing conglomerates in Late Archean and Early Proterozoic metasedimentary rocks have been discovered in southern Wyoming. The mineral deposits were found by applying the time and strata bound model for the origin of uranium-bearing quartz-pebble conglomerates to favorable rock types within a geologic terrane known from prior regional mapping. No mineral deposits have been discovered that are of current (1981) economic interest, but preliminary resource estimates indicate that over 3418 tons of uranium and over 1996 tons of thorium are present in the Medicine Bow Mountains and that over 440 tons of uranium and 6350 tons of thorium are present in Sierra Madre. Sampling has been inadequate to determine gold resources. High grade uranium deposits have not been detected by work to date but local beds of uranium-bearing conglomerate contain as much as 1380 ppM uranium over a thickness of 0.65 meters. This project has involved geologic mapping at scales from 1/6000 to 1/50,000 detailed sampling, and the evaluation of 48 diamond drill holes, but the area is too large to fully establish the economic potential with the present information. This first volume summarizes the geologic setting and geologic and geochemical characteristics of the uranium-bearing conglomerates. Volume 2 contains supporting geochemical data, lithologic logs from 48 drill holes in Precambrian rocks, and drill site geologic maps and cross-sections from most of the holes. Volume 3 is a geostatistical resource estimate of uranium and thorium in quartz-pebble conglomerates

Study on integrated evaluation of sandstone-hosted uranium metallogenic potential in southern Yili basin

International Nuclear Information System (INIS)

Han Shaoyang; Ke Dan; Xu Jianguo; Zheng Enjiu; Li Shengxiang

2008-01-01

Plenty of geological data have been accumulated during mineral resource survey in China; under the guidance of new metallogenic theories, it is an important task of how to use these data most effectively for the new cycle uranium survey. In this paper, the flow of establishing the integrated mineral deposits prospecting model for sandstone-hosted uranium deposits is put forward. Based on studying geologic, hydrogeologic and regional geophysical field characteristics of representative uranium deposits No. 512 in southern Yili basin, its multi-source information descriptive model has been established, from which 512-type integrated prospecting models of sandstone-hosted uranium orefield and deposits are summarized. According to the established integrated prospecting models, the metallogenic information extraction of sandstone-hosted uranium deposits has completed in the study area. Finally, the integrated quantitative evaluation of sandstone-hosted uranium metallogenic potential is performed by using the evidence weighing method to integrate middle scale multi-source metallogenic information in the southern Yili basin, and good prediction effect is obtained. (authors)

Uranium

International Nuclear Information System (INIS)

Whillans, R.T.

1981-01-01

Events in the Canadian uranium industry during 1980 are reviewed. Mine and mill expansions and exploration activity are described, as well as changes in governmental policy. Although demand for uranium is weak at the moment, the industry feels optimistic about the future. (LL)

A study of uranium adsorption to single-crystal tungsten

Energy Technology Data Exchange (ETDEWEB)

Samin, Adib; Hastings, Aaron; Zhang, Jinsuo, E-mail: jzhang@osu.edu

2015-12-15

In this study we explore the adsorption of uranium to the (110) plane of tungsten. Potential functions were constructed to describe the interaction of adsorbed uranium atoms with the tungsten surface and the lateral interaction between adsorbed uranium atoms. Next, the behavior of the uranium adlayer under different conditions was studied through a Monte Carlo simulation of the grand canonical Hamiltonian in an off-lattice model. Our results are consistent with available studies in the literature. The simulation results indicate that the temperature and dipole–dipole interactions play an important role in governing the adsorption process.

A study of uranium adsorption to single-crystal tungsten

International Nuclear Information System (INIS)

Samin, Adib; Hastings, Aaron; Zhang, Jinsuo

2015-01-01

In this study we explore the adsorption of uranium to the (110) plane of tungsten. Potential functions were constructed to describe the interaction of adsorbed uranium atoms with the tungsten surface and the lateral interaction between adsorbed uranium atoms. Next, the behavior of the uranium adlayer under different conditions was studied through a Monte Carlo simulation of the grand canonical Hamiltonian in an off-lattice model. Our results are consistent with available studies in the literature. The simulation results indicate that the temperature and dipole–dipole interactions play an important role in governing the adsorption process.

Uranium industry annual 1985

International Nuclear Information System (INIS)

1986-11-01

This report consists of two major sections. The first addresses uranium raw materials activities and covers the following topics: exploration activities and expenditures, resources and reserves, mine production of uranium, production of uranium concentrate, and industry employment. The second major section is concerned with the following uranium marketing activities: uranium purchase commitments, uranium prices, procurement arrangements, uranium imports and exports, enrichment services, inventories, secondary market activities, utility market requirements, and related topics. A glossary and appendices are included to assist the reader in interpreting the substantial array of statistical data in this report and to provide background information about the survey

Uranium

Energy Technology Data Exchange (ETDEWEB)

Williams, R M

1976-01-01

Evidence of expanding markets, improved prices and the short supply of uranium became abundantly clear in 1975, providing the much needed impetus for widespread activity in all phases of uranium operations. Exploration activity that had been at low levels in recent years in Canada was evident in most provinces as well as the Northwest Territories. All producers were in the process of expanding their uranium-producing facilities. Canada's Atomic Energy Control Board (AECB) by year-end had authorized the export of over 73,000 tons of U/sub 3/0/sub 8/ all since September 1974, when the federal government announced its new uranium export guidelines. World production, which had been in the order of 25,000 tons of U/sub 3/0/sub 8/ annually, was expected to reach about 28,000 tons in 1975, principally from increased output in the United States.

Equilibrium, kinetic and thermodynamic studies of uranium biosorption by calcium alginate beads

International Nuclear Information System (INIS)

Bai, Jing; Fan, Fangli; Wu, Xiaolei; Tian, Wei; Zhao, Liang; Yin, Xiaojie; Fan, Fuyou; Li, Zhan; Tian, Longlong; Wang, Yang; Qin, Zhi; Guo, Junsheng

2013-01-01

Calcium alginate beads are potential biosorbent for radionuclides removal as they contain carboxyl groups. However, until now limited information is available concerning the uptake behavior of uranium by this polymer gel, especially when sorption equilibrium, kinetics and thermodynamics are concerned. In present work, batch experiments were carried out to study the equilibrium, kinetics and thermodynamics of uranium sorption by calcium alginate beads. The effects of initial solution pH, sorbent amount, initial uranium concentration and temperature on uranium sorption were also investigated. The determined optimal conditions were: initial solution pH of 3.0, added sorbent amount of 40 mg, and uranium sorption capacity increased with increasing initial uranium concentration and temperature. Equilibrium data obtained under different temperatures were fitted better with Langmuir model than Freundlich model, uranium sorption was dominated by a monolayer way. The kinetic data can be well depicted by the pseudo-second-order kinetic model. The activation energy derived from Arrhenius equation was 30.0 kJ/mol and the sorption process had a chemical nature. Thermodynamic constants such as ΔH 0 , ΔS 0 and ΔG 0 were also evaluated, results of thermodynamic study showed that the sorption process was endothermic and spontaneous. -- Highlights: • Equilibrium, kinetics and thermodynamics of uranium sorption by CaAlg were studied. • Equilibrium studies show that Langmuir isotherm better fit with experimental data. • Pseudo-second-order kinetics model is found to be well depicting the kinetic data. • Thermodynamic study shows that the sorption process is endothermic and spontaneous

Chapter 1. General information about uranium. 1.3. Uranium ores

International Nuclear Information System (INIS)

Khakimov, N.; Nazarov, Kh.M.; Mirsaidov, I.U.

2012-01-01

The uranium ores were described. It was found that uranium ores and natural mineral formations containing uranium and its compounds, can be found in concentrations that are technically possible for industrial utilization and which are economically profitable. It was defined that oxidation levels of uranium minerals have an impact on their reprocessing technology and behavior in hydrometallurgical re partition. It was found that the chemical composition of ores has a decisive importance during selection of their reprocessing method.

Derived enriched uranium market

International Nuclear Information System (INIS)

Rutkowski, E.

1996-01-01

The potential impact on the uranium market of highly enriched uranium from nuclear weapons dismantling in the Russian Federation and the USA is analyzed. Uranium supply, conversion, and enrichment factors are outlined for each country; inventories are also listed. The enrichment component and conversion components are expected to cause little disruption to uranium markets. The uranium component of Russian derived enriched uranium hexafluoride is unresolved; US legislation places constraints on its introduction into the US market

Radiological Modeling for Determination of Derived Concentration Levels of an Area with Uranium Residual Material - 13533

Energy Technology Data Exchange (ETDEWEB)

Perez-Sanchez, Danyl [CIEMAT, Avenida Complutense 40, 28040, Madrid (Spain)

2013-07-01

As a result of a pilot project developed at the old Spanish 'Junta de Energia Nuclear' to extract uranium from ores, tailings materials were generated. Most of these residual materials were sent back to different uranium mines, but a small amount of it was mixed with conventional building materials and deposited near the old plant until the surrounding ground was flattened. The affected land is included in an area under institutional control and used as recreational area. At the time of processing, uranium isotopes were separated but other radionuclides of the uranium decay series as Th-230, Ra-226 and daughters remain in the residue. Recently, the analyses of samples taken at different ground's depths confirmed their presence. This paper presents the methodology used to calculate the derived concentration level to ensure that the reference dose level of 0.1 mSv y-1 used as radiological criteria. In this study, a radiological impact assessment was performed modeling the area as recreational scenario. The modelization study was carried out with the code RESRAD considering as exposure pathways, external irradiation, inadvertent ingestion of soil, inhalation of resuspended particles, and inhalation of radon (Rn-222). As result was concluded that, if the concentration of Ra-226 in the first 15 cm of soil is lower than, 0.34 Bq g{sup -1}, the dose would not exceed the reference dose. Applying this value as a derived concentration level and comparing with the results of measurements on the ground, some areas with a concentration of activity slightly higher than latter were found. In these zones the remediation proposal has been to cover with a layer of 15 cm of clean material. This action represents a reduction of 85% of the dose and ensures compliance with the reference dose. (authors)

Equations of state for enriched uranium and uranium alloy to 3500 MPa

International Nuclear Information System (INIS)

Bai Chaomao; Hai Yuying; Liu Jenlong; Li Zhenrong

1990-04-01

The volume compressions of 6 kinds of cast materials including enriched uranium, poor uranium, U-0.57 wt% Ti, U-0.33 wt% Nb, U-2.85 wt% Nb and U-7.5 wt% Nb-3.3 wt% Zr have been determined by monitoring piston displacements in a piston cylinder apparatus with double strengthening rings to 3500 MPa at room temperature. The dilation of the cylinder vessel and the press deformation were corrected by some experiments. The calculational data free from using the standard sample closed with used standard sample. The volume compressions of enriched uranium and poor uranium are nearly coincident. Pure uranium is more compressible than uranium alloys. These values of enriched uranium are in close agreement with values of Bridgman's pure uranium. The fitting coefficients of Bridgman's polynomial and Anderson's equation of state and isothermal bulk modules for the above materials are given