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Sample records for calcrete-gypcrete uranium model

  1. Possible variations on the calcrete-gypcrete uranium model

    International Nuclear Information System (INIS)

    Carlisle, D.

    1980-01-01

    Genetic models and favorability criteria for calcrete and gypcrete uranium deposits based upon Yeelirrie and other occurrences in Western Australia and upon Langer Henirich and others in Namibia-South West Africa are summarized. Viable analogues of these world-class deposits have not yet been found in USA even though several of the favorable conditions occur in the southwest. A principal deterrent to economic concentration has been tectonic instability. But even in the most favorable areas it is not clear that climates have ever been sufficiently similar to that of the valley-calcrete region of Western Australia. Extensive, thick valley (nonpedogenic) calcretes such as those which host the carnotite in Australia and in Namibia have not been documented here. Nevertheless, submarginal occurrances of carnotite have been found in southwestern United States in small bodies of nonpedogenic and mixed pedogenic-nonpedogenic calcrete. Much of the study is based upon occurrences of carnotite-bearing calcrete and calcrete-gypcrete in the Republic of South Africa. Several of these are described briefly. Some reference is also made to new occurrences and to new data on previously described occurrences on the Namib Desert. Possible variations on the Western Australian and Namibia-South West Africa models which are considered are capillary rise of U in solution, addition of new uraniferous sediment over a calcrete, lateral access of U into a pedogenic calcrete, reworking of U from a weekly mineralized pedogenic calcrete or gypcrete into a new or reconstituted calcrete, or into an unrelated environment for fixation of U

  2. Possible variations on the calcrete-gypcrete uranium model

    Energy Technology Data Exchange (ETDEWEB)

    Carlisle, D.

    1980-01-01

    Genetic models and favorability criteria for calcrete and gypcrete uranium deposits based upon Yeelirrie and other occurrences in Western Australia and upon Langer Henirich and others in Namibia-South West Africa are summarized. Viable analogues of these world-class deposits have not yet been found in USA even though several of the favorable conditions occur in the southwest. A principal deterrent to economic concentration has been tectonic instability. But even in the most favorable areas it is not clear that climates have ever been sufficiently similar to that of the valley-calcrete region of Western Australia. Extensive, thick valley (nonpedogenic) calcretes such as those which host the carnotite in Australia and in Namibia have not been documented here. Nevertheless, submarginal occurrances of carnotite have been found in southwestern United States in small bodies of nonpedogenic and mixed pedogenic-nonpedogenic calcrete. Much of the study is based upon occurrences of carnotite-bearing calcrete and calcrete-gypcrete in the Republic of South Africa. Several of these are described briefly. Some reference is also made to new occurrences and to new data on previously described occurrences on the Namib Desert. Possible variations on the Western Australian and Namibia-South West Africa models which are considered are capillary rise of U in solution, addition of new uraniferous sediment over a calcrete, lateral access of U into a pedogenic calcrete, reworking of U from a weekly mineralized pedogenic calcrete or gypcrete into a new or reconstituted calcrete, or into an unrelated environment for fixation of U.

  3. Surficial uranium deposits: summary and conclusions

    International Nuclear Information System (INIS)

    Otton, J.K.

    1984-01-01

    Uranium occurs in a variety of surficial environments in calcretes, gypcretes, silcretes, dolocretes and in organic sediments. Groundwater moving on low gradients generates these formations and, under favourable circumstances, uranium deposits. A variety of geomorphic settings can be involved. Most surficial deposits are formed in desert, temperate wetland, tropical, or transitional environments. The largest deposits known are in sedimentary environments in arid lands. The deposits form largely by the interaction of ground or surface waters on the geomorphic surface in favourable geologic terrains and climates. The deposits are commonly in the condition of being formed or reconstituted, or being destroyed. Carnotite is common in desert deposits while in wetland deposits no uranium minerals may be seen. Radioactive disequilibrium is common, particularly in wetland deposits. Granites and related rocks are major source rocks and most large deposits are in regions with enriched uranium contents, i.e. significantly greater than 5 ppm uranium. Uranium dissolution and transport is usually under oxidizing conditions. Transport in desert conditions is usually as a bicarbonate. A variety of fixation mechanisms operate to extract the uranium and form the deposits. Physical barriers to groundwater flow may initiate ore deposition. Mining costs are likely to be low because of the near surface occurrence, but there may be processing difficulties as clay may be present and the saline or carbonate content may be high. (author)

  4. 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

  5. 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)

  6. 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

  7. 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

  8. 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

  9. 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.

  10. 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)

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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.

  16. 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

  17. 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.

  18. Uraniferous surficial deposits

    International Nuclear Information System (INIS)

    Toens, P.D.; Hambleton-Jones, B.B.

    1980-10-01

    As a result of the discovery of uranium in surficial deposits of Tertiary to Recent age, in Australia and Southern Africa, increasing attention is being paid to the location and understanding of the genesis of these deposits. The paper discusses the definitions and terminology currently in use and a classification of these deposits is presented. It is concluded that in order to obtain a measure of clarity, the terms calcrete, gypcrete and dolocrete should not be used to describe the uraniferous valley-fill deposits of Southern Africa and Australia [af

  19. 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.

  20. 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.

  1. 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)

  2. 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

  3. 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

  4. 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.

  5. 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

  6. 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)

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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.)

  13. 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

  14. 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)

  15. 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

  16. 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)

  17. 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

  18. 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

  19. 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.

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  6. Uranium

    International Nuclear Information System (INIS)

    Perkin, D.J.

    1982-01-01

    Developments in the Australian uranium industry during 1980 are reviewed. Mine production increased markedly to 1841 t U 3 O 8 because of output from the new concentrator at Nabarlek and 1131 t of U 3 O 8 were exported at a nominal value of $37.19/lb. Several new contracts were signed for the sale of yellowcake from Ranger and Nabarlek Mines. Other developments include the decision by the joint venturers in the Olympic Dam Project to sink an exploration shaft and the release of an environmental impact statement for the Honeymoon deposit. Uranium exploration expenditure increased in 1980 and additions were made to Australia's demonstrated economic uranium resources. A world review is included

  7. Uranium

    International Nuclear Information System (INIS)

    Gabelman, J.W.; Chenoweth, W.L.; Ingerson, E.

    1981-01-01

    The uranium production industry is well into its third recession during the nuclear era (since 1945). Exploration is drastically curtailed, and many staffs are being reduced. Historical market price production trends are discussed. A total of 3.07 million acres of land was acquired for exploration; drastic decrease. Surface drilling footage was reduced sharply; an estimated 250 drill rigs were used by the uranium industry during 1980. Land acquisition costs increased 8%. The domestic reserve changes are detailed by cause: exploration, re-evaluation, or production. Two significant discoveries of deposits were made in Mohave County, Arizona. Uranium production during 1980 was 21,850 short tons U 3 O 8 ; an increase of 17% from 1979. Domestic and foreign exploration highlights were given. Major producing areas for the US are San Juan basin, Wyoming basins, Texas coastal plain, Paradox basin, northeastern Washington, Henry Mountains, Utah, central Colorado, and the McDermitt caldera in Nevada and Oregon. 3 figures, 8 tables

  8. 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

  9. Uranium

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    Recent decisions by the Australian Government will ensure a significant expansion of the uranium industry. Development at Roxby Downs may proceed and Ranger may fulfil two new contracts but the decision specifies that apart from Roxby Downs, no new mines should be approved. The ACTU maintains an anti-uranium policy but reaction to the decision from the trade union movement has been muted. The Australian Science and Technology Council (ASTEC) has been asked by the Government to conduct an inquiry into a number of issues relating to Australia's role in the nuclear fuel cycle. The inquiry will examine in particular Australia's nuclear safeguards arrangements and the adequacy of existing waste management technology. In two additional decisions the Government has dissociated itself from a study into the feasibility of establishing an enrichment operation and has abolished the Uranium Advisory Council. Although Australian reserves account for 20% of the total in the Western World, Australia accounts for a relatively minor proportion of the world's uranium production

  10. Uranium

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    The French Government has decided to freeze a substantial part of its nuclear power programme. Work has been halted on 18 reactors. This power programme is discussed, as well as the effect it has on the supply of uranium by South Africa

  11. 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

  12. 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)

  13. 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

  14. 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)

  15. Central Ukraine Uranium Province: The genetic model

    International Nuclear Information System (INIS)

    Emetz, A.; Cuney, M.

    2014-01-01

    Ukraine produces ~1,100 t U per year from the Michurinske, Centralne, Novokostantynivske and Vatutinske U deposits in the Kirovograd U district of the Central Ukraine Uranium Province (CUUP) consisting of about 20 deposits and numerous showings related to ~1.8 Ga sodium metasomatites developed in the Lower Paleoproterozoic granite-gneiss and iron formations of the Ingul Megablock of the Ukrainian Shield. Two deposits (the Zhovta Richka and Pervomayske) were mined out tens kilometers eastward in iron formations of the Kryvy Rig – Kremenchug mining district. Nametasomatite fields with scarce sub-economical U-mineralization were revealed by geophysical (magnetometry and gravimetry) and drilling programs northward in granitised gneisses around the younger Korsun-Novomyrgorod rapakivi pluton consisting of A2-type within plate granitoids which were emplaced during decompression melting at ~1.75 Ga. The present work aims to demonstrate structural and geochemical factors related to Na-metasomatism, and to mark out geochemical and tectonical parameters which were favorable for U-accumulation using data on deep seismic survey, geological structure analysis, and mineralogical and geochemical investigations of metasomatites. In the Ingul Megablock, Na-metasomatites occur along shear fault zones mostly oriented N-S. Metasomatites form complicate systems of plate- and lens-like bodies of aegirine-riebeckite albitites surrounded by dequartzified host rocks. Elemental alteration during Na-metasomatism demonstrates simple exchange of Si, K, Rb, Ba and Cs by Na, Ca, and locally V and U. δ 18 O H 2 O (300-400ºC) for albitizing hydrothermal solutions is near “zero”, typically for surficial water. These data suggest host rock interaction with hot marine waters. Persistent Na-metasomatic alterations extend along major tectonic faults for several kilometres with variable thicknesses reaching some hundreds meters in the zones of intense brecciation developed in the places of fault

  16. 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

  17. 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

  18. 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

  19. Uranium

    International Nuclear Information System (INIS)

    Battey, G.C.; McKay, A.D.

    1988-01-01

    Production for 1986 was 4899 t U 3 O 8 (4154 t U), 30% greater than in 1985, mainly because of a 39% increase in production at Ranger. Exports for 1986 were 4166 t U 3 O 8 at an average f.o.b. unit value of $40.57/lb U 3 O 8 . Private exploration expenditure for uranium in Australia during the 1985-86 fiscal year was $50.2 million. Plans were announced to increase the nominal capacity of the processing plant at Ranger from 3000 t/year U 3 O 8 to 4500 t and later to 6000 t/year. Construction and initial mine development at Olympic Dam began in March. Production is planned for mid 1988 at an annual rate of 2000 t U 3 O 8 , 30 000 t Cu, and 90 000 oz (2800 kg) Au. The first long-term sales agreement was concluded in September 1986. At the Manyingee deposit, testing of the alkaline solution mining method was completed, and the treatment plant was dismantled. Spot market prices (in US$/lb U 3 O 8 ) quoted by Nuexco were generally stable. From January-October the exchange value fluctuated from US$17.00-US$17.25; for November and December it was US$16.75. Australia's Reasonably Assured Resources of uranium recoverable at less than US$80/kg U at December 1986 were estimated as 462 000 t U, 3000 t U less than in 1985. This represents 30% of the total low-cost RAR in the WOCA (World Outside the Centrally Planned Economy Areas) countries. Australia also has 257 000 t U in the low-cost Estimated Additional Resources Category I, 29% of the WOCA countries' total resources in this category

  20. 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)

  1. 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)

  2. 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)

  3. 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

  4. 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

  5. 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

  6. 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.

  7. 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)

  8. 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)

  9. 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

  10. 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)

  11. 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)

  12. 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

  13. 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

  14. 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

  15. A respiratory model for uranium aluminide based on occupational data

    International Nuclear Information System (INIS)

    Leggett, R W; Eckerman, K F; Jr, J D Boice

    2005-01-01

    As part of an epidemiological study, doses from intake of radionuclides were estimated for workers employed during a 52-year period at the Rocketdyne/Atomics International facility in California. The facility was involved in a variety of research programmes, including nuclear fuel fabrication, spent nuclear fuel decladding, and reactor operation and disassembly. Most of the documented intakes involved inhalation of enriched uranium (U), fission products, or plutonium (Pu). Highest doses were estimated for a group of workers exposed to airborne uranium aluminide (UAl x ) during the fabrication of reactor fuel plates. Much of the exposure to UAl x occurred early in the fuel fabrication programme, before it was recognised that intake and lung retention were being underestimated from urinary data due to an unexpected delayed dissolution of the inhaled material. In workers who had been removed from exposure, the rate of urinary excretion of U increased for a few months, peaked, and then declined at a rate consistent with moderately soluble material. This pattern differs markedly from the monotonically decreasing absorption rates represented by the default absorption types in the Human Respiratory Tract Model (HRTM) of the International Commission on Radiological Protection (ICRP). This paper summarises the findings on the behaviour of UAl x in these workers and describes material-specific parameter values of the HRTM based on this information

  16. 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

  17. 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

  18. 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.

  19. 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.)

  20. 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

  1. 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

  2. Modeling uranium transport in acidic contaminated groundwater with base addition

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Fan [Institute of Tibetan Plateau Research, Chinese Academy of Sciences; Luo, Wensui [ORNL; Parker, Jack C. [University of Tennessee, Knoxville (UTK); Brooks, Scott C [ORNL; Watson, David B [ORNL; Jardine, Philip [University of Tennessee, Knoxville (UTK); Gu, Baohua [ORNL

    2011-01-01

    This study investigates reactive transport modeling in a column of uranium(VI)-contaminated sediments with base additions in the circulating influent. The groundwater and sediment exhibit oxic conditions with low pH, high concentrations of NO{sub 3}{sup -}, SO{sub 4}{sup 2-}, U and various metal cations. Preliminary batch experiments indicate that additions of strong base induce rapid immobilization of U for this material. In the column experiment that is the focus of the present study, effluent groundwater was titrated with NaOH solution in an inflow reservoir before reinjection to gradually increase the solution pH in the column. An equilibrium hydrolysis, precipitation and ion exchange reaction model developed through simulation of the preliminary batch titration experiments predicted faster reduction of aqueous Al than observed in the column experiment. The model was therefore modified to consider reaction kinetics for the precipitation and dissolution processes which are the major mechanism for Al immobilization. The combined kinetic and equilibrium reaction model adequately described variations in pH, aqueous concentrations of metal cations (Al, Ca, Mg, Sr, Mn, Ni, Co), sulfate and U(VI). The experimental and modeling results indicate that U(VI) can be effectively sequestered with controlled base addition due to sorption by slowly precipitated Al with pH-dependent surface charge. The model may prove useful to predict field-scale U(VI) sequestration and remediation effectiveness.

  3. Modeling uranium transport in acidic contaminated groundwater with base addition

    International Nuclear Information System (INIS)

    Zhang Fan; Luo Wensui; Parker, Jack C.; Brooks, Scott C.; Watson, David B.; Jardine, Philip M.; Gu Baohua

    2011-01-01

    This study investigates reactive transport modeling in a column of uranium(VI)-contaminated sediments with base additions in the circulating influent. The groundwater and sediment exhibit oxic conditions with low pH, high concentrations of NO 3 - , SO 4 2- , U and various metal cations. Preliminary batch experiments indicate that additions of strong base induce rapid immobilization of U for this material. In the column experiment that is the focus of the present study, effluent groundwater was titrated with NaOH solution in an inflow reservoir before reinjection to gradually increase the solution pH in the column. An equilibrium hydrolysis, precipitation and ion exchange reaction model developed through simulation of the preliminary batch titration experiments predicted faster reduction of aqueous Al than observed in the column experiment. The model was therefore modified to consider reaction kinetics for the precipitation and dissolution processes which are the major mechanism for Al immobilization. The combined kinetic and equilibrium reaction model adequately described variations in pH, aqueous concentrations of metal cations (Al, Ca, Mg, Sr, Mn, Ni, Co), sulfate and U(VI). The experimental and modeling results indicate that U(VI) can be effectively sequestered with controlled base addition due to sorption by slowly precipitated Al with pH-dependent surface charge. The model may prove useful to predict field-scale U(VI) sequestration and remediation effectiveness.

  4. Modeling uranium transport in acidic contaminated groundwater with base addition

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Fan, E-mail: zhangfan@itpcas.ac.cn [Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, P.O. Box 2871, Beijing, 100085 (China); Luo Wensui [Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021 (China); Parker, Jack C. [Institute for a Secure and Sustainable Environment, Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Brooks, Scott C.; Watson, David B. [Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Jardine, Philip M. [Biosystems Engineering and Soil Science Department, University of Tennessee, Knoxville, TN 37996 (United States); Gu Baohua [Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2011-06-15

    This study investigates reactive transport modeling in a column of uranium(VI)-contaminated sediments with base additions in the circulating influent. The groundwater and sediment exhibit oxic conditions with low pH, high concentrations of NO{sub 3}{sup -}, SO{sub 4}{sup 2-}, U and various metal cations. Preliminary batch experiments indicate that additions of strong base induce rapid immobilization of U for this material. In the column experiment that is the focus of the present study, effluent groundwater was titrated with NaOH solution in an inflow reservoir before reinjection to gradually increase the solution pH in the column. An equilibrium hydrolysis, precipitation and ion exchange reaction model developed through simulation of the preliminary batch titration experiments predicted faster reduction of aqueous Al than observed in the column experiment. The model was therefore modified to consider reaction kinetics for the precipitation and dissolution processes which are the major mechanism for Al immobilization. The combined kinetic and equilibrium reaction model adequately described variations in pH, aqueous concentrations of metal cations (Al, Ca, Mg, Sr, Mn, Ni, Co), sulfate and U(VI). The experimental and modeling results indicate that U(VI) can be effectively sequestered with controlled base addition due to sorption by slowly precipitated Al with pH-dependent surface charge. The model may prove useful to predict field-scale U(VI) sequestration and remediation effectiveness.

  5. 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

  6. 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

  7. Hybrid empirical--theoretical approach to modeling uranium adsorption

    International Nuclear Information System (INIS)

    Hull, Larry C.; Grossman, Christopher; Fjeld, Robert A.; Coates, John T.; Elzerman, Alan W.

    2004-01-01

    An estimated 330 metric tons of U are buried in the radioactive waste Subsurface Disposal Area (SDA) at the Idaho National Engineering and Environmental Laboratory (INEEL). An assessment of U transport parameters is being performed to decrease the uncertainty in risk and dose predictions derived from computer simulations of U fate and transport to the underlying Snake River Plain Aquifer. Uranium adsorption isotherms were measured for 14 sediment samples collected from sedimentary interbeds underlying the SDA. The adsorption data were fit with a Freundlich isotherm. The Freundlich n parameter is statistically identical for all 14 sediment samples and the Freundlich K f parameter is correlated to sediment surface area (r 2 =0.80). These findings suggest an efficient approach to material characterization and implementation of a spatially variable reactive transport model that requires only the measurement of sediment surface area. To expand the potential applicability of the measured isotherms, a model is derived from the empirical observations by incorporating concepts from surface complexation theory to account for the effects of solution chemistry. The resulting model is then used to predict the range of adsorption conditions to be expected in the vadose zone at the SDA based on the range in measured pore water chemistry. Adsorption in the deep vadose zone is predicted to be stronger than in near-surface sediments because the total dissolved carbonate decreases with depth

  8. Filtration and Hydrogen Reaction Modeling in a Depleted Uranium Bed

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Kwang Jin; Kim, Yean Jin; Ahn, Do Hee; Chung, Hong Suk [UST, Daejeon (Korea, Republic of); Kang, Hee Seok [KAERI, Daejeon (Korea, Republic of); Yun, Sei Hun [NFRI, Daejeon (Korea, Republic of)

    2016-05-15

    The storage and delivery system (SDS) stores the hydrogen isotopes and delivers them to the fuel injection system. Depleted uranium (DU) was chosen as a hydrogen isotope storage material. The hydrogen isotopes stored in the SDS are in the form of DU hydride confined in the primary and secondary containment within a glove box with an argon atmosphere. In this study, we performed a modeling study of the SDS. A modeling study is practically important because an experimental study requires comparatively more money and time. We estimated the hydrogen atomic ratio in DU hydride by two empirical equations we formulated. Two empirical equations are used to determine Pressure-Composition-Temperature (PCT) curves and the hydrogen atomic ratio in DU hydride. In addition, we present the effect of pressure and temperature in the hydriding and dehydriding. A modeling study of the SDS was performed in this study. It is practically important to save more money and time. The hydrogen atomic ratio in the DU hydride was estimated using two empirical equations. The two empirical equations are modified and reformulated to determine PCT curves and the hydrogen atomic ratio in DU hydride. All parameters that are required to solve two empirical equations are obtained from the experimental data. The derived parameters are utilized for the numerical simulations. In the numerical simulations, the effects of pressure and temperature on both the hydriding and dehydriding reaction rates are confirmed.

  9. Geochemical modeling of uranium mill tailings: a case study

    International Nuclear Information System (INIS)

    Peterson, S.R.; Felmy, A.R.; Serne, R.J.; Gee, G.W.

    1983-08-01

    Liner failure was not found to be a problem when various acidic tailings solutions leached through liner materials for periods up to 3 y. On the contrary, materials that contained over 30% clay showed a decrease in permeability with time in the laboratory columns. The decreases in permeability noted above are attributed to pore plugging resulting from the precipitation of minerals and solids. This precipitation takes place due to the increase in pH of the tailings solution brought about by the buffering capacity of the soil. Geochemical modeling predicts, and x-ray characterization confirms, that precipitation of solids from solution is occurring in the acidic tailings solution/liner interactions studied. X-ray diffraction identified gypsum and alunite group minerals, such as jarosite, as having precipitated after acidic tailings solutions reacted with clay liners. The geochemical modeling and experimental work described above were used to construct an equilibrium conceptual model consisting of minerals and solid phases. This model was developed to represent a soil column. A computer program was used as a tool to solve the system of mathematical equations imposed by the conceptual chemical model. The combined conceptual model and computer program were used to predict aqueous phase compositions of effluent solutions from permeability cells packed with geologic materials and percolated with uranium mill tailings solutions. An initial conclusion drawn from these studies is that the laboratory experiments and geochemical modeling predictions were capable of simulating field observations. The same mineralogical changes and contaminant reductions observed in the laboratory studies were found at a drained evaporation pond (Lucky Mc in Wyoming) with a 10-year history of acid attack. 24 references, 5 figures 5 tables

  10. 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)

  11. Relative risk models of lung cancer in uranium miners

    Energy Technology Data Exchange (ETDEWEB)

    Tomasek, L [National Radiation Protection Institute, Prague (Czech Republic); Placek, V [Inst. for Expertises and Emergencies, Pribram-Kamenna (Czech Republic)

    1996-12-31

    The study population of the S cohort (studies of underground miners of uranium and other substances as the source of information on long term effects of exposure to radon and its progeny) involve uranium miners, that started underground work at the Jachymov and Horni Slavkov mines in the period 1978-1959, and had worked at least for four years. A total 4320 men satisfied these criteria. During the decade up to 1990, follow-up of the cohort mainly relied on the national population registry. In order to improve the follow-u, a series of additional checks were conducted: in the files of the Czech and Slovak Pensions Offices, by local enquires, and by direct correspondence. These additional efforts resulted in an increase of more than 10% in the numbers of known men to have died or emigrated. An exceptional feature of the S study is the large number of measurements of radon concentrations made in each mine-shaft (mean number per year and shaft was 223 in the period 1949-1960). Each man`s annual exposures to radon progeny in terms of working levels were estimated combining measurement data with men`s employment details. The excess relative risk models were used in the form RR = c(1 + ERR(w,x)), where ERR is excess relative risk, w and x denote exposure history and modifying variable, and c is an intercept term that allows the mortality rate for `unexposed` cohort to differ from that in the general population. The increased mortality (O/E=1.58; where O is observed and E is expected cases among collected death cases in the cohort) in the cohort, generally, somewhat lower ratios than one reflect the non-industrial character of the region, with the exception of lung cancer in man. The differences in the O/E ratios for lung cancer among the separate communities indicate that even in the situation of generally lower mortality, the dependence of lung cancer mortality on radon exposure cannot be excluded. 3 tabs., 6 refs.

  12. 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

  13. A thermal modelling of displacement cascades in uranium dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Martin, G., E-mail: guillaume.martin@cea.fr [CEA – DEN/DEC/SESC/LLCC, Bât. 352, 13108 Saint-Paul-Lez-Durance Cedex (France); Garcia, P.; Sabathier, C. [CEA – DEN/DEC/SESC/LLCC, Bât. 352, 13108 Saint-Paul-Lez-Durance Cedex (France); Devynck, F.; Krack, M. [Laboratory for Reactor Physics and Systems Behaviour, Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland); Maillard, S. [CEA – DEN/DEC/SESC/LLCC, Bât. 352, 13108 Saint-Paul-Lez-Durance Cedex (France)

    2014-05-01

    The space and time dependent temperature distribution was studied in uranium dioxide during displacement cascades simulated by classical molecular dynamics (MD). The energy for each simulated radiation event ranged between 0.2 keV and 20 keV in cells at initial temperatures of 700 K or 1400 K. Spheres into which atomic velocities were rescaled (thermal spikes) have also been simulated by MD to simulate the thermal excitation induced by displacement cascades. Equipartition of energy was shown to occur in displacement cascades, half of the kinetic energy of the primary knock-on atom being converted after a few tenths of picoseconds into potential energy. The kinetic and potential parts of the system energy are however subjected to little variations during dedicated thermal spike simulations. This is probably due to the velocity rescaling process, which impacts a large number of atoms in this case and would drive the system away from a dynamical equilibrium. This result makes questionable MD simulations of thermal spikes carried out up to now (early 2014). The thermal history of cascades was compared to the heat equation solution of a punctual thermal excitation in UO{sub 2}. The maximum volume brought to a temperature above the melting temperature during the simulated cascade events is well reproduced by this simple model. This volume eventually constitutes a relevant estimate of the volume affected by a displacement cascade in UO{sub 2}. This definition of the cascade volume could also make sense in other materials, like iron.

  14. 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

  15. 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)

  16. 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

  17. 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

  18. 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

  19. 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.

  20. 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

  1. 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

  2. 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

  3. 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.

  4. 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

  5. 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

  6. 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.

  7. Beaufort group uranium mineralization - a model that may aid exploration

    International Nuclear Information System (INIS)

    Stuart-Williams, V.

    1982-01-01

    The ore bodies examined while working on the Pristerognathus Diictodon Assemblage Zone West of Beaufort West are of the URAVAN type (URA - uranium, VAN - vanadium). It was found that uranium mineralization in any one ore body was not strictly random and tends to be associated with a fairly consistent sandstone and siltstone geometry. Mineralization is only found where coalescence between the two sandstones has occurred and it disappears where the sandstones remain coalesced. At a point of coalescence the fluids from the upper and lower sandstone are mixed, the oxidizing fluid penetrating progressively deeper in the sandstone couplet until the entire couplet is oxidizing. This generates a weakly dipping REDOX front. The REDOX front is not considered strong enough to have precipitated uranyl carbonate complexes in transport

  8. 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.)

  9. 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

  10. 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

  11. 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.

  12. 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

  13. 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

  14. 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

  15. 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)

  16. 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)

  17. 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

  18. 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)

  19. 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)

  20. 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

  1. 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.

  2. 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.

  3. 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

  4. 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

  5. Occupational safety and health program for a model uranium mill

    International Nuclear Information System (INIS)

    Miller, H.T.

    1981-01-01

    The basic purpose of this paper is to suggest procedures and practices to insure that no employee working in a uranium milling operation receives exposure to radioactive, toxic, or other materials or agents that might produce a permanent, deleterious effect upon his physical health and well-being. This program is also designed to insure that each employee can carry out his assigned duties without risk to his health or to that of his fellow workers. The total program is envisioned as a balanced combination of occupational hygiene and radiation monitoring. This includes surveying, air sampling, personnel dosimetry, bioassay, medical surveillance, epidemiology, and training - all backed by a thoroughly tested and evaluated set of emergency procedures. The program, as presented, is keyed to the results of monitoring, surveying, air sampling, medical surveillance, and epidemiology - it being obvious that no problem can result when no hazard can be identified

  6. 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)

  7. 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)

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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.

  7. 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)

  8. 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)

  9. 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

  10. Uranium deposits of Gabon and Oklo reactors. Metallogenic model for rich deposits of the lower proterozoic

    International Nuclear Information System (INIS)

    Gauthier-Lafaye, F.

    1986-05-01

    The geology of the Franceville basin (Gabon) is examined: stratigraphy, tectonics and geodynamics. The mobile zone of the Ogooue is specially studied: lithology, metamorphism and tectonics, isotopic geochronologic data are given. The different uranium deposits are described. A whole chapter is devoted to the study of Oklo natural nuclear reactor. A metallogenic model is proposed evidencing conditions required for deposit genesis. Tectonics, microstructures sedimentology, organic matter, diagenesis and uraniferous mineralizations are examined [fr

  11. 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

  12. 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

  13. 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)

  14. 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)

  15. 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

  16. 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.

  17. Development and test of models in the natural analogue studies of the Cigar Lake uranium deposit

    Energy Technology Data Exchange (ETDEWEB)

    Liu Jinsong

    1995-06-01

    In the model of steady-state near-field mass transport, the model concepts are essentially the same as those in the models developed for a nuclear waste repository. The validity of the model is tested against known helium release. The models shows that the release of Uranium is negligibly low, the release of sulfate is roughly balanced by the release of dissolved hydrogen, indicating possible water radiolysis. The release of radionuclides is in agreement with field observations. In the model of radiation energy deposition, the issue of water radiolysis is addressed directly by calculating the radiation energy deposited in the pore water in the ore body. In the test of the models of coupled solute transport with geochemical reactions, the observed hematisation in the clay halo adjacent to the ore is simulated. The model results show that, at a certain rate of oxidant production, hematite can possibly precipitate in the clay adjacent to the ore body, as observed. The model results also reveal a threshold of oxidant production rate for hematisation. In general, the three models are capable of predicting the most prominent features observed in the deposit. All models point to a certain extent of water radiolysis in the ore body. In addition, the existence of a negligibly permeable clay halo and the presence of reducing minerals like pyrite in the ore and nearby are of vital importance for the preservation of the Uranium ore. 107 refs, 7 figs, 5 tabs.

  18. Development and test of models in the natural analogue studies of the Cigar Lake uranium deposit

    International Nuclear Information System (INIS)

    Liu Jinsong.

    1995-06-01

    In the model of steady-state near-field mass transport, the model concepts are essentially the same as those in the models developed for a nuclear waste repository. The validity of the model is tested against known helium release. The models shows that the release of Uranium is negligibly low, the release of sulfate is roughly balanced by the release of dissolved hydrogen, indicating possible water radiolysis. The release of radionuclides is in agreement with field observations. In the model of radiation energy deposition, the issue of water radiolysis is addressed directly by calculating the radiation energy deposited in the pore water in the ore body. In the test of the models of coupled solute transport with geochemical reactions, the observed hematisation in the clay halo adjacent to the ore is simulated. The model results show that, at a certain rate of oxidant production, hematite can possibly precipitate in the clay adjacent to the ore body, as observed. The model results also reveal a threshold of oxidant production rate for hematisation. In general, the three models are capable of predicting the most prominent features observed in the deposit. All models point to a certain extent of water radiolysis in the ore body. In addition, the existence of a negligibly permeable clay halo and the presence of reducing minerals like pyrite in the ore and nearby are of vital importance for the preservation of the Uranium ore. 107 refs, 7 figs, 5 tabs

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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.

  4. 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)

  5. 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)

  6. 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

  7. 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.

  8. 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.

  9. 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

  10. Thermochemical modeling of the plutonium and uranium-plutonium dioxides

    International Nuclear Information System (INIS)

    Besmann, T.M.; Lindemer, T.B.

    1984-01-01

    The chemical thermodynamic properties of the actinide oxides have long been of interest for nuclear fuel design and for predicting fuel behavior under accident conditions. The result of such interest has been the publication of many studies over several decades containing thousands of measurements. The calcium fluorite structure and phases have been intensely studied, with in excess of 1000 data points having been determined. The object of the current work is to develop quantitative models of and which accurately describe the oxygen potential-temperature-composition behavior of the phases. The entire available data base of oxygen potential-temperature-composition values were extracted for use in the development of the models for the plutonia and mixed oxide phases. With perhaps the exception of Babelot et al., little effort has been made to utilize the large existing data base in such analyses. These data were instrumental in developing our models for the oxides, indicating the appropriate oxygen potential-composition relationships and providing for the determination of parametric values. The modeling approach used by us is fundamentally simple, utilizing the assumption that the complex oxides can be described as solutions of oxides with invariant stoichiometries. The chemical thermodynamic models for and described here are among the first to make extensive use of the large oxygen potential-temperature-composition data base which exists for these systems. These relatively simple models should be easily applied to the design of fuel compositions the analysis of behavior during burnup, and the development of codes for accident analysis. 5 references

  11. 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

  12. Model of a Generic Natural Uranium Conversion Plant ? Suggested Measures to Strengthen International Safeguards

    Energy Technology Data Exchange (ETDEWEB)

    Raffo-Caiado, Ana Claudia [ORNL; Begovich, John M [ORNL; Ferrada, Juan J [ORNL

    2009-11-01

    This is the final report that closed a joint collaboration effort between DOE and the National Nuclear Energy Commission of Brazil (CNEN). In 2005, DOE and CNEN started a collaborative effort to evaluate measures that can strengthen the effectiveness of international safeguards at a natural uranium conversion plant (NUCP). The work was performed by DOE s Oak Ridge National Laboratory and CNEN. A generic model of a NUCP was developed and typical processing steps were defined. Advanced instrumentation and techniques for verification purposes were identified and investigated. The scope of the work was triggered by the International Atomic Energy Agency s 2003 revised policy concerning the starting point of safeguards at uranium conversion facilities. Prior to this policy only the final products of the uranium conversion plant were considered to be of composition and purity suitable for use in the nuclear fuel cycle and therefore, subject to the IAEA safeguards control. DOE and CNEN have explored options for implementing the IAEA policy, although Brazil understands that the new policy established by the IAEA is beyond the framework of the Quadripartite Agreement of which it is one of the parties, together with Argentina, the Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials (ABACC) and the IAEA. Two technical papers on this subject were published at the 2005 and 2008 INMM Annual Meetings.

  13. Preliminary discussion on the application of the geological conceptual model method of uranium ore formation

    International Nuclear Information System (INIS)

    Ma Guangzhong; Wei Mingji; Luo Yiyue

    1992-01-01

    The geological conceptual model method of uranium ore formation is established on the basis of geological theory and apriorism. Variables are screened with the application of the method of mathematical geology to find out the variables which are more contributed. In combination with the practical situation in Xikang-Yunnan axis, the variables are compiled and graded so as to determine the optimal ore-controlling factor and to establish the statistical predictive model which is of geological significance. The resources evaluation work has been conducted in the Late Proterozoic geological terrain in Xikang-Yunnan axis

  14. 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!!!

  15. Simplified modeling photo-ionisation of uranium in Silva project

    International Nuclear Information System (INIS)

    Bodin, B.; Pourre-Brichot, P.; Valadier, L.

    2000-01-01

    SILVA is a process which targets 235 U by photo-ionization. It is therefore important to compute the proportion of ionized atoms depending on the properties of the lasers. The interaction between atoms and lasers occurs via the link between the Maxwell and Schroedinger equations. This kind of approach is only feasible for a few simple cases: e.g. wave plane or simple laser profiling. Introducing the characteristics of SILVA, computation time increases substantially (several hundred days per kilogram of vapor). To circumvent this problem, we wrote a program (Jackpot) that treats photo-ionization by a simplified model: kinetics equations. However, various optical components were introduced with absorption factor by wavelength, to account for the effects of optics systems on the trajectory. Instead of seeking the complex wavefunction solutions of the Maxwell-Schroedinger equations, we solve a system where the unknown values are a set of populations. The size of the set depends only on the number of hold points in the process. Recent work shows that we can converge towards the same results as the Maxwell-Schroedinger system if we can fit the cross-sections of the kinetic system correctly. As to the optical aspect, Jackpot can handle diffraction. In this case, it solves the propagation equation of an electric field by a double Fourier transform method. For interactions with mirrors, the new direction of a ray is calculated with Descartes law, applying a numerical phase mask to the electric field. We account for diaphragmation mechanisms as well as the absorption law for each mirror, by a real factor by wavelength. Jackpot is simple to use and can be used to predict experimental results. Jackpot is now a library calling by a script written in Python. Changes are being made for a closer approach to reality (real laser, new photo-ionization model)

  16. 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

  17. 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

  18. A theoretical model of processes of irradiation of workers in uranium mines

    International Nuclear Information System (INIS)

    Zettwoog, Pierre.

    1980-11-01

    A quantity caled mine 'irradiativity', which is the ratio of collective dose to the production of uranium 'metal', is introduced. A distinction is made between irradiativity due to external exposure and that due to radon. A mathematical model to predict irradiativity has been developed using specific data from a mine: a) amount and distribution of work in areas of access and production; b) technology of ore extraction, especially the productivity of ore extraction, which is a basic parameter; c) protection technologies, especially the ventilation system; and d) geologic conditions. A numerical example is presented [fr

  19. 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

  20. 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.

  1. 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

  2. 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

  3. 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

  4. A new mechanistic and engineering fission gas release model for a uranium dioxide fuel

    International Nuclear Information System (INIS)

    Lee, Chan Bock; Yang, Yong Sik; Kim, Dae Ho; Kim, Sun Ki; Bang, Je Geun

    2008-01-01

    A mechanistic and engineering fission gas release model (MEGA) for uranium dioxide (UO 2 ) fuel was developed. It was based upon the diffusional release of fission gases from inside the grain to the grain boundary and the release of fission gases from the grain boundary to the external surface by the interconnection of the fission gas bubbles in the grain boundary. The capability of the MEGA model was validated by a comparison with the fission gas release data base and the sensitivity analyses of the parameters. It was found that the MEGA model correctly predicts the fission gas release in the broad range of fuel burnups up to 98 MWd/kgU. Especially, the enhancement of fission gas release in a high-burnup fuel, and the reduction of fission gas release at a high burnup by increasing the UO 2 grain size were found to be correctly predicted by the MEGA model without using any artificial factor. (author)

  5. Turbulent precipitation of uranium oxalate in a vortex reactor - experimental study and modelling

    International Nuclear Information System (INIS)

    Sommer de Gelicourt, Y.

    2004-03-01

    Industrial oxalic precipitation processed in an un-baffled magnetically stirred tank, the Vortex Reactor, has been studied with uranium simulating plutonium. Modelling precipitation requires a mixing model for the continuous liquid phase and the solution of population balance for the dispersed solid phase. Being chemical reaction influenced by the degree of mixing at molecular scale, that commercial CFD code does not resolve, a sub-grid scale model has been introduced: the finite mode probability density functions, and coupled with a model for the liquid energy spectrum. Evolution of the dispersed phase has been resolved by the quadrature method of moments, first used here with experimental nucleation and growth kinetics, and an aggregation kernel based on local shear rate. The promising abilities of this local approach, without any fitting constant, are strengthened by the similarity between experimental results and simulations. (author)

  6. Post Audit of a Field Scale Reactive Transport Model of Uranium at a Former Mill Site

    Science.gov (United States)

    Curtis, G. P.

    2015-12-01

    Reactive transport of hexavalent uranium (U(VI)) in a shallow alluvial aquifer at a former uranium mill tailings site near Naturita CO has been monitored for nearly 30 years by the US Department of Energy and the US Geological Survey. Groundwater at the site has high concentrations of chloride, alkalinity and U(VI) as a owing to ore processing at the site from 1941 to 1974. We previously calibrated a multicomponent reactive transport model to data collected at the site from 1986 to 2001. A two dimensional nonreactive transport model used a uniform hydraulic conductivity which was estimated from observed chloride concentrations and tritium helium age dates. A reactive transport model for the 2km long site was developed by including an equilibrium U(VI) surface complexation model calibrated to laboratory data and calcite equilibrium. The calibrated model reproduced both nonreactive tracers as well as the observed U(VI), pH and alkalinity. Forward simulations for the period 2002-2015 conducted with the calibrated model predict significantly faster natural attenuation of U(VI) concentrations than has been observed by the persistent high U(VI) concentrations at the site. Alternative modeling approaches are being evaluating evaluated using recent data to determine if the persistence can be explained by multirate mass transfer models developed from experimental observations at the column scale(~0.2m), the laboratory tank scale (~2m), the field tracer test scale (~1-4m) or geophysical observation scale (~1-5m). Results of this comparison should provide insight into the persistence of U(VI) plumes and improved management options.

  7. Modeling of the Microchemistry for Diffusion of Selected Impurities in Uranium

    International Nuclear Information System (INIS)

    Kirkpatrick, J. R.; Bullock, J.S. IV

    2001-01-01

    framework and an advance toward a comprehensive model of uranium metal microchemical distributions

  8. 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.)

  9. 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)

  10. 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.

  11. 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...

  12. 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)

  13. Turbulent precipitation of uranium oxalate in a vortex reactor - experimental study and modelling; Precipitation turbulente d'oxalate d'uranium en reacteur vortex - etude experimentale et modelisation

    Energy Technology Data Exchange (ETDEWEB)

    Sommer de Gelicourt, Y

    2004-03-15

    Industrial oxalic precipitation processed in an un-baffled magnetically stirred tank, the Vortex Reactor, has been studied with uranium simulating plutonium. Modelling precipitation requires a mixing model for the continuous liquid phase and the solution of population balance for the dispersed solid phase. Being chemical reaction influenced by the degree of mixing at molecular scale, that commercial CFD code does not resolve, a sub-grid scale model has been introduced: the finite mode probability density functions, and coupled with a model for the liquid energy spectrum. Evolution of the dispersed phase has been resolved by the quadrature method of moments, first used here with experimental nucleation and growth kinetics, and an aggregation kernel based on local shear rate. The promising abilities of this local approach, without any fitting constant, are strengthened by the similarity between experimental results and simulations. (author)

  14. Lung cancer from radon and smoking: a multistage model for the WISMUT uranium miners

    International Nuclear Information System (INIS)

    Dillen, Teun van; Bijwaard, Harmen; Schnelzer, Maria; Kreuzer, Michaela; Grosche, Bernd

    2008-01-01

    Full text: In the world's third-largest uranium-mining province located in areas of Saxony and Thuringia in the former German Democratic Republic, the WISMUT Company conducted extensive uranium mining starting in 1946. Up to 1990, when mining activities were discontinued, most of the 400,000 employees had been exposed to uranium ore dust and radon and its progeny. It is well established that, besides smoking, such exposures are associated with an increased risk of lung cancer. From about 130,000 known miners a huge cohort of 59,000 miners has been formed and in an epidemiological analysis lung cancer risks have been evaluated (Grosche et al., 2006). We will present an alternative approach using a biologically-based multistage carcinogenesis model quantifying the lung-cancer risk related to both the exposure to radon and smoking habits. This mechanistic technique allows for extrapolation to the low exposures that are important for present-day radiation protection purposes and the transfer of risk across populations. The model is applied to a sub-cohort of about 35,000 persons who were employed at WISMUT after 1955, with known annual exposures estimated from the job-exposure matrix (Lehmann et al., 2004). Unfortunately, detailed information on smoking is missing for most miners. However, this information has been retrieved in two case-control studies, one of which was nested in the cohort while the other was not (Brueske-Hohlfeld et al., 2006). For these studies, the relevant smoking parameters are assembled in so-called smoking spectra that are next projected onto the entire cohort using a Monte-Carlo sampling method. Individual smoking habits that are randomly assigned to the cohort members, together with the information on annual exposure to radon, is used as an input for the multistage model. Model parameters related to radon and tobacco exposure are fitted with a maximum-likelihood technique. We will show results of the observed and expected lung

  15. 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

  16. 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

  17. Modelling of radon control and air cleaning requirements in underground uranium mines

    International Nuclear Information System (INIS)

    El Fawal, M.; Gadalla, A.

    2014-01-01

    As a part of a comprehensive study concerned with control workplace short-lived radon daughter concentration in underground uranium mines to safe levels, a computer program has been developed and verified, to calculate ventilation parameters e.g. local pressures, flow rates and radon daughter concentration levels. The computer program is composed of two parts, one part for mine ventilation and the other part for radon daughter levels calculations. This program has been validated in an actual case study to calculate radon concentration levels, pressure and flow rates required to maintain acceptable levels of radon concentrations in each point of the mine. The required fan static pressure and the approximate energy consumption were also estimated. The results of the calculations have been evaluated and compared with similar investigation. It was found that the calculated values are in good agreement with the corresponding values obtained using ''REDES'' standard ventilation modelling software. The developed computer model can be used as an available tool to help in the evaluation of ventilation systems proposed by mining authority, to assist the uranium mining industry in maintaining the health and safety of the workers underground while efficiently achieving economic production targets. It could be used also for regulatory inspection and radiation protection assessments of workers in the underground mining. Also with using this model, one can effectively design, assess and manage underground mine ventilation systems. Values of radon decay products concentration in units of working level, pressures drop and flow rates required to reach the acceptable radon concentration relative to the recommended levels, at different extraction points in the mine and fan static pressure could be estimated which are not available using other software. (author)

  18. 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)

  19. 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

  20. 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

  1. 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)

  2. Computer-modeling codes to improve exploration nuclear-logging methods. National Uranium Resource Evaluation

    International Nuclear Information System (INIS)

    Wilson, R.D.; Price, R.K.; Kosanke, K.L.

    1983-03-01

    As part of the Department of Energy's National Uranium Resource Evaluation (NURE) project's Technology Development effort, a number of computer codes and accompanying data bases were assembled for use in modeling responses of nuclear borehole logging Sondes. The logging methods include fission neutron, active and passive gamma-ray, and gamma-gamma. These CDC-compatible computer codes and data bases are available on magnetic tape from the DOE Technical Library at its Grand Junction Area Office. Some of the computer codes are standard radiation-transport programs that have been available to the radiation shielding community for several years. Other codes were specifically written to model the response of borehole radiation detectors or are specialized borehole modeling versions of existing Monte Carlo transport programs. Results from several radiation modeling studies are available as two large data bases (neutron and gamma-ray). These data bases are accompanied by appropriate processing programs that permit the user to model a wide range of borehole and formation-parameter combinations for fission-neutron, neutron-, activation and gamma-gamma logs. The first part of this report consists of a brief abstract for each code or data base. The abstract gives the code name and title, short description, auxiliary requirements, typical running time (CDC 6600), and a list of references. The next section gives format specifications and/or directory for the tapes. The final section of the report presents listings for programs used to convert data bases between machine floating-point and EBCDIC

  3. FIREPLUME model for plume dispersion from fires: Application to uranium hexafluoride cylinder fires

    International Nuclear Information System (INIS)

    Brown, D.F.; Dunn, W.E.

    1997-06-01

    This report provides basic documentation of the FIREPLUME model and discusses its application to the prediction of health impacts resulting from releases of uranium hexafluoride (UF 6 ) in fires. The model application outlined in this report was conducted for the Draft Programmatic Environmental Impact Statement for Alternative Strategies for the Long-Term Management and Use of Depleted UF 6 . The FIREPLUME model is an advanced stochastic model for atmospheric plume dispersion that predicts the downwind consequences of a release of toxic materials from an explosion or a fire. The model is based on the nonbuoyant atmospheric dispersion model MCLDM (Monte Carlo Lagrangian Dispersion Model), which has been shown to be consistent with available laboratory and field data. The inclusion of buoyancy and the addition of a postprocessor to evaluate time-varying concentrations lead to the current model. The FIREPLUME model, as applied to fire-related UF 6 cylinder releases, accounts for three phases of release and dispersion. The first phase of release involves the hydraulic rupture of the cylinder due to heating of the UF 6 in the fire. The second phase involves the emission of material into the burning fire, and the third phase involves the emission of material after the fire has died during the cool-down period. The model predicts the downwind concentration of the material as a function of time at any point downwind at or above the ground. All together, five fire-related release scenarios are examined in this report. For each scenario, downwind concentrations of the UF 6 reaction products, uranyl fluoride and hydrogen fluoride, are provided for two meteorological conditions: (1) D stability with a 4-m/s wind speed, and (2) F stability with a 1-m/s wind speed

  4. A screening model for depleted uranium testing using environmental radiation monitoring data

    International Nuclear Information System (INIS)

    Dunfrund, F.L.; Ebinger, M.H.; Hansen, W.R.

    1996-01-01

    Information from an ecological risk assessment of depleted uranium test areas at Yuma Proving Ground (YPG) was used to update the required environmental radiation monitoring (ERM) plan. Data to be collected for the ERM can also be used to evaluate the potential for adverse radiological and toxicological effects to terrestrial reptiles and mammals in the affected areas. We developed a spreadsheet-based screening model that incorporates the ERM data and associated uncertainties. The purpose of the model is to provide a conservative estimate of radiological exposure of terrestrial, biota to DU using the ERM data. The uncertainty in the estimate is also predicted so that the variation in the radiological exposure can be used in assessing potential adverse effects from DU testing. Toxicological effects are evaluated as well as radiological effects in the same program using the same data. Our presentation shows an example data set, model calculations, and the report of expected radiation dose rates and probable kidney burdens of select mammals and reptiles. The model can also be used in an inverse mode to calculate the soil concentration required to give either a radiological dose that would produce a potential adverse effect such as fatal cancer or a toxicological dose that would result in nephrotoxic effects in mammals

  5. Estimation of uranium resources by life-cycle or discovery-rate models: a critique

    International Nuclear Information System (INIS)

    Harris, D.P.

    1976-10-01

    This report was motivated primarily by M. A. Lieberman's ''United States Uranium Resources: An Analysis of Historical Data'' (Science, April 30). His conclusion that only 87,000 tons of U 3 O 8 resources recoverable at a forward cost of $8/lb remain to be discovered is criticized. It is shown that there is no theoretical basis for selecting the exponential or any other function for the discovery rate. Some of the economic (productivity, inflation) and data issues involved in the analysis of undiscovered, recoverable U 3 O 8 resources on discovery rates of $8 reserves are discussed. The problem of the ratio of undiscovered $30 resources to undiscovered $8 resources is considered. It is concluded that: all methods for the estimation of unknown resources must employ a model of some form of the endowment-exploration-production complex, but every model is a simplification of the real world, and every estimate is intrinsically uncertain. The life-cycle model is useless for the appraisal of undiscovered, recoverable U 3 O 8 , and the discovery rate model underestimates these resources

  6. Mathematic modeling of reactor fuel radiation creep at example of uranium and its alloys

    International Nuclear Information System (INIS)

    Tarasov, V.A.

    2001-01-01

    The model of a radiation creep is explained within the framework of the mechanism of gliding and climbing dislocations based on the conception of a dislocation as not ideal sink for point radiation defects (PRD). The offered model is efficient for installed concentration PRD, considerably exceeding thermally steady state concentration. The gliding of dislocation are describing as due to moving dislocation kinks in Peierl's relief. The climbing of dislocation are describing as due to moving dislocation jogs. The mathematical model for the computer program simulating the offered model of radiation creep is developed. The complex of the computer programs simulating the radiation creep is developed. The computer simulation researches are conducted and the outcomes of a research of a kinetics of a flexible sliding and climbing dislocation interacting to obstacles of a various type (spherical centre of extension, dislocation prismatic loop and their spatially random distributions) for various installed concentration PRD, external loadings and temperatures are represented. The curves of installed rate of a radiation creep from temperature for uranium and its alloys with small additions of molybdenum (from 0,9 to 1,3 %) are obtained

  7. Control of remediation of uranium deposit Straz with use of numerical modelling approach

    International Nuclear Information System (INIS)

    Novak, J.; Muzak, J.; Smetana, R.

    2002-01-01

    The chemical mining of uranium on the deposit Straz has caused large contamination of groundwater of cretaceous collectors in Straz block of Northbohemian cretaceous table. The low cenomanian aquifer where the uranium deposit is placed is mainly afflicted. In the cenomanian collector there is now more than 4.8 mil. t dissolved solids mainly SO 4 2- , Al, Fe, NH 4 + etc. The total salinity reaches up to 80 g/l. The upper laying turonian collector is drinking water reservoir for larger region. Its contamination is weaker than in cenomanian collector. Use of complex 3D Transport - Reaction Model can be divided into two separate parts. First modelling step is a quantification of overflow between individual mesh elements calculated out of calibrated mixed-hybrid flow model. Two different types of mathematical models are used to accomplish the task: Flow model based on a primary formulation of finite element method, which calculates spatial distribution of piezometric head and flow velocity vectors in selected points of area considered (finite element mesh nodes). This model exactly describes hydraulic situation in area studied; Flow model based on mixed-hybrid formulation of finite element method. This model strictly complies with exact water balance at inter-element faces. In the second part transport-reaction model based on finite volume method is used for calculations using pre-calculated advective velocity field in the area considered. The finite-element mesh covering about 40 km 2 consists of about 16,000 spatial elements. In the leaching fields area the length of the triangular edge is 100-150 meters, vertically the horizon is split into 9-13 layers. The geological boundary-lines were constructed from a database containing information about almost 10 thousand wells. Permeability parameters are defined on the bases of hydrogeological model calculations (calibration) and their vertical distribution is defined more precisely using the GTIS (Geotechnological

  8. Dynamic Characteristics and Model for Centralization Reaction of Acidic Tailings From Heap Leaching of Uranium Ore

    International Nuclear Information System (INIS)

    Ding Dexin; Liu Yulong; Li Guangyue; Wang Youtuan

    2010-01-01

    Centralization tests were carried out on acidic tailings from heap leaching of uranium ore by using CaO, NaOH and NH 4 OH. The variations of pH with time were measured for the three centralization systems and the dynamic models for the systems were set up by regressing the measured data. The centralization process consists of the fast reaction phase representing the reaction between the centralization agent and the acid on the surface of the tailing's particles and the slow diffusion-reaction phase representing the diffusion-reaction between the centralization agent and the acid within the tailing's particles. The non-linear coupling and feedback function model for the diffusion-reaction of the centralization agent can reflect the process and mode of the centralization reaction. There is a non-linear oscillation in the variation of pH within the centralization systems. The dynamic model for the tailing's centralization reaction can fit the pH variation within the centralization systems. (authors)

  9. Metallogenetic regularity exploration model and prospecting potential of the mesocenozoic volcanic type uranium deposit in the east of south China

    International Nuclear Information System (INIS)

    Wang Yusheng; Li Wenjun

    1995-01-01

    During the Meso-Cenozoic era, the crust in the east of South China experienced an evolutional process of compression-relaxed extension-local disintegration, correspondingly, three periods of volcanic activity were developed, forming initial volcanic cycle, principal volcanic cycle and caldera volcanic cycle. The caldera volcanic cycle was expressed as a 'bimodal type' rock suite, indicating the entering of the region into an evolutional stage of new embryonic refitting. The volcanic type uranium deposit is characterized by ore-formation during caldera volcanic cycle, ore control by the mobile belt of caldera volcanic cycle and double superposition and concentration, and it can be summarized as a new unconformity-related type uranium deposit of caldera volcanic series, which is divided into three morphological types: body type, layer type and vein type and relevant exploration models are proposed. The new unconformity-related type uranium deposits of the caldera volcanic series in the east of South China have a great prospecting potential. The tectonomagmatic complex area of the caldera volcanic cycle developed on the granite basement is the favourable target area in searching for large uranium deposits from now on

  10. A model for recovery of scrap monolithic uranium molybdenum fuel by electrorefining

    Science.gov (United States)

    Van Kleeck, Melissa A.

    The goal of the Reduced Enrichment for Research and Test Reactors program (RERTR) is toreduce enrichment at research and test reactors, thereby decreasing proliferation risk at these facilities. A new fuel to accomplish this goal is being manufactured experimentally at the Y12 National Security Complex. This new fuel will require its own waste management procedure,namely for the recovery of scrap from its manufacture. The new fuel is a monolithic uraniummolybdenum alloy clad in zirconium. Feasibility tests were conducted in the Planar Electrode Electrorefiner using scrap U-8Mo fuel alloy. These tests proved that a uranium product could be recovered free of molybdenum from this scrap fuel by electrorefining. Tests were also conducted using U-10Mo Zr clad fuel, which confirmed that product could be recovered from a clad version of this scrap fuel at an engineering scale, though analytical results are pending for the behavior of Zr in the electrorefiner. A model was constructed for the simulation of electrorefining the scrap material produced in the manufacture of this fuel. The model was implemented on two platforms, Microsoft Excel and MatLab. Correlations, used in the model, were developed experimentally, describing area specific resistance behavior at each electrode. Experiments validating the model were conducted using scrap of U-10Mo Zr clad fuel in the Planar Electrode Electrorefiner. The results of model simulations on both platforms were compared to experimental results for the same fuel, salt and electrorefiner compositions and dimensions for two trials. In general, the model demonstrated behavior similar to experimental data but additional refinements are needed to improve its accuracy. These refinements consist of a function for surface area at anode and cathode based on charge passed. Several approximations were made in the model concerning areas of electrodes which should be replaced by a more accurate function describing these areas.

  11. Towards a consistent geochemical model for prediction of uranium(VI) removal from groundwater by ferrihydrite

    International Nuclear Information System (INIS)

    Gustafsson, Jon Petter; Daessman, Ellinor; Baeckstroem, Mattias

    2009-01-01

    Uranium(VI), which is often elevated in granitoidic groundwaters, is known to adsorb strongly to Fe (hydr)oxides under certain conditions. This process can be used in water treatment to remove U(VI). To develop a consistent geochemical model for U(VI) adsorption to ferrihydrite, batch experiments were performed and previous data sets reviewed to optimize a set of surface complexation constants using the 3-plane CD-MUSIC model. To consider the effect of dissolved organic matter (DOM) on U(VI) speciation, new parameters for the Stockholm Humic Model (SHM) were optimized using previously published data. The model, which was constrained from available X-ray absorption fine structure (EXAFS) spectroscopy evidence, fitted the data well when the surface sites were divided into low- and high-affinity binding sites. Application of the model concept to other published data sets revealed differences in the reactivity of different ferrihydrites towards U(VI). Use of the optimized SHM parameters for U(VI)-DOM complexation showed that this process is important for U(VI) speciation at low pH. However in neutral to alkaline waters with substantial carbonate present, Ca-U-CO 3 complexes predominate. The calibrated geochemical model was used to simulate U(VI) adsorption to ferrihydrite for a hypothetical groundwater in the presence of several competitive ions. The results showed that U(VI) adsorption was strong between pH 5 and 8. Also near the calcite saturation limit, where U(VI) adsorption was weakest according to the model, the adsorption percentage was predicted to be >80%. Hence U(VI) adsorption to ferrihydrite-containing sorbents may be used as a method to bring down U(VI) concentrations to acceptable levels in groundwater

  12. 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

  13. 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)

  14. 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)

  15. Surface complexation models for uranium adsorption in the sub-surface environment

    International Nuclear Information System (INIS)

    Payne, T.E.

    2007-01-01

    Adsorption experiments with soil component minerals under a range of conditions are being used to develop models of uranium(VI) uptake in the sub-surface environment. The results show that adsorption of U on iron oxides and clay minerals is influenced by chemical factors including the pH, partial pressure of CO 2 , and the presence of ligands such as phosphate. Surface complexation models (SCMs) can be used to simulate U adsorption on these minerals. The SCMs are based on plausible mechanistic assumptions and describe the experimental data more adequately than Kd values or sorption isotherms. It is conceptually possible to simulate U sorption data on complex natural samples by combining SCMs for individual component minerals. This approach was used to develop a SCM for U adsorption to mineral assemblages from Koongarra (Australia), and produced a reasonable description of U uptake. In order to assess the applicability of experimental data to the field situation, in-situ measurements of U distributions between solid and liquid phases were undertaken at the Koongarra U deposit. This field partitioning data showed a satisfactory agreement with laboratory sorption data obtained under comparable conditions. (author)

  16. 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

  17. 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.

  18. Modelling of the underwater disposal of uranium mine tailings in Elliot Lake

    International Nuclear Information System (INIS)

    Halbert, B.E.; Scharer, J.M.; Chakravatti, J.L.; Barnes, E.

    1982-01-01

    Underwater disposal of uranium mine tailings from the Elliot Lake area operations offers potential advantages in controlling radon gas release, emission of airborne particulate matter, and acid production from pyrites in the tailings. In addition, the proximity of the three active properties, one owned by Denison Mines Limited and two by Rio Algom Limited, to a large deep lake has spurred interest in the concept. It has been estimated that the placement of approximately 150 million tonnes of tailings from future planned production would occupy less than 20% of the lake volume. To assess the applicability of the underwater tailings disposal concept, a multi-stage study was developed in conjunction with the regulatory agencies. The most important facet identified for investigation during the first-stage investigations was an assessment of the effects of underwater disposal on water quality in the Serpent River Basin watershed. To simulate the effects of underwater disposal, a computer simulation routine was developed and integrated with a water quality model previously developed for the Basin which predicts levels of total dissolved solids, ammonia, dissolved radium-226 and pH. The underwater disposal model component reflects the effects of direct input of tailings into the hypolimnion, the chemical/biological transformation of dissolved constituents in the water column, the reactions of pyritic tailings deposited on the bottom, and the flux of dissolved constituents from the tailings into the water column. To establish site-specific values for the underwater disposal model, field and laboratory experiments were utilized to evaluate rates of pyrite and ammonia oxidation, and pH-alkalinity relationships. The results of these studies and their use in the water quality model are discussed. In addition, the results of two model run simulations are presented. (author)

  19. Conceptual model of ecosystems in landscape of Uranium Mining of Andujar (Spain)

    International Nuclear Information System (INIS)

    1994-01-01

    This study analyzes the site of uranium mining to Andujar and its ecosystems: aquatic and terrestrial. Socioeconomic description, chemical risks, radiological risks, radionuclide transfer, and ecological consequences studies are presented as well. (Author)

  20. MODELING OF THE SOLVENT EXTRACTION EQUILIBRIUM OF URANIUM (VI SULFATE WITH ALAMINE 336

    Directory of Open Access Journals (Sweden)

    É. C. Avelar

    Full Text Available Abstract The present study investigated the solvent extraction of uranium from sulfate acid solutions using Alamine 336 as an extractant dissolved in commercial kerosene Exxsol D-100 and 5% v/v of tridecanol as a modifying agent at room temperature (25±2 ºC and an aqueous/organic volumetric ratio of unity. Experiments were carried out at typical concentration levels like those used at the uranium plant of INB (Indústrias Nucleares do Brasil, Brazil. Data fitting using the slope analysis method revealed that uranium is extracted by Alamine 336 as UO2SO4 and UO2(SO422- species, forming (R3NH+2UO2(SO422- in the organic phase; the extraction of the species UO2(SO434- seems improbable for the operating conditions investigated. The extraction of uranium is significantly reduced when the concentrations of sulfate and chloride ions in the aqueous phase are increased.

  1. Approaches to surface complexation modeling of Uranium(VI) adsorption on aquifer sediments

    Science.gov (United States)

    Davis, J.A.; Meece, D.E.; Kohler, M.; Curtis, G.P.

    2004-01-01

    Uranium(VI) adsorption onto aquifer sediments was studied in batch experiments as a function of pH and U(VI) and dissolved carbonate concentrations in artificial groundwater solutions. The sediments were collected from an alluvial aquifer at a location upgradient of contamination from a former uranium mill operation at Naturita, Colorado (USA). The ranges of aqueous chemical conditions used in the U(VI) adsorption experiments (pH 6.9 to 7.9; U(VI) concentration 2.5 ?? 10-8 to 1 ?? 10-5 M; partial pressure of carbon dioxide gas 0.05 to 6.8%) were based on the spatial variation in chemical conditions observed in 1999-2000 in the Naturita alluvial aquifer. The major minerals in the sediments were quartz, feldspars, and calcite, with minor amounts of magnetite and clay minerals. Quartz grains commonly exhibited coatings that were greater than 10 nm in thickness and composed of an illite-smectite clay with occluded ferrihydrite and goethite nanoparticles. Chemical extractions of quartz grains removed from the sediments were used to estimate the masses of iron and aluminum present in the coatings. Various surface complexation modeling approaches were compared in terms of the ability to describe the U(VI) experimental data and the data requirements for model application to the sediments. Published models for U(VI) adsorption on reference minerals were applied to predict U(VI) adsorption based on assumptions about the sediment surface composition and physical properties (e.g., surface area and electrical double layer). Predictions from these models were highly variable, with results overpredicting or underpredicting the experimental data, depending on the assumptions used to apply the model. Although the models for reference minerals are supported by detailed experimental studies (and in ideal cases, surface spectroscopy), the results suggest that errors are caused in applying the models directly to the sediments by uncertain knowledge of: 1) the proportion and types of

  2. 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)

  3. 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

  4. Empirical modeling of solvent extraction of uranium from sulphuric acid medium using PC-88A and TOPO as extractants

    International Nuclear Information System (INIS)

    Biswas, S.; Roy, S.B.; Pathak, P.N.; Manchanda, V.K.; Singh, D.K.

    2011-01-01

    Extraction behavior of uranium (VI) from sulphuric acid medium using PC-88A (H 2 A 2 , dimer form) and a mixture of PC-88A + TOPO in n-dodecane has been investigated. The extraction data have been used to develop a mathematical model correlating percentage extraction (%E) with PC-88A and TOPO concentration. It can be used to predict the steady-state concentrations of metal ion under the conditions of the present work. (author)

  5. Kinetics and equilibrium modeling of uranium(VI) sorption by bituminous shale from aqueous solution

    International Nuclear Information System (INIS)

    Ortaboy, Sinem; Atun, Gülten

    2014-01-01

    Highlights: • Oil shales are sedimentary rocks containing a polymeric matter in a mineral matrix. • Sorption potential of bituminous shale (BS) for uranium recovery was investigated. • U(VI) sorption increased with decreasing pH and increasing temperature. • Kinetic data were analyzed based on single and two resistance diffusion models. • The results fit well to the McKay equation assuming film and intraparticle diffusion. - Abstract: Sorption of U(VI) onto a bituminous shale (BS) from a nuclear power plant project site in Black Sea region was investigated for potential risk assessment when it releases into the environment with contaminated ground and surface water. The sorption characteristics of the BS for U(VI) recovery were evaluated as a function of contact time, adsorbent dosage, initial concentration, pH and temperature. Kinetic results fit better with pseudo-second-order model rather than pseudo-first-order. The possibility of diffusion process was analyzed based on Weber–Morris intra-particle diffusion model. The McKay equation assuming film- and intraparticle diffusion better predicted the data than the Vermeulen approximation presuming surface diffusion. Equilibrium sorption data were modeled according to the Langmuir, Dubinin–Radushkevich (D–R) and Freundlich isotherm equations. Sorption capacity increased from 0.10 to 0.15 mmol g −1 in 298–318 K temperature range. FT-IR analysis and pH dependent sorption studies conducted in hydroxide and carbonate media revealed that U(VI) species were sorbed in uranyl and its hydroxo forms on the BS. Desorption studies showed that U(VI) leaching with Black Sea water was negligible from the loaded BS. The activation parameters (E a , ΔH ∗ and ΔG ∗ ) estimated from diffusion coefficients indicated the presence of an energy barrier in the sorption system. However, thermodynamic functions derived from sorption equilibrium constants showed that overall sorption process was spontaneous in nature

  6. 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.

  7. Modeling exposure to depleted uranium in support of decommissioning at Jefferson Proving Ground, Indiana

    Energy Technology Data Exchange (ETDEWEB)

    Ebinger, M.H. [Los Alamos National Lab., NM (United States); Oxenburg, T.P. [Army Test and Evaluation Command, Aberdeen Proving Ground, MD (United States)

    1997-02-01

    Jefferson Proving Ground was used by the US Army Test and Evaluation Command for testing of depleted uranium munitions and closed in 1995 under the Base Realignment and Closure Act. As part of the closure of JPG, assessments of potential adverse health effects to humans and the ecosystem were conducted. This paper integrates recent information obtained from site characterization surveys at JPG with environmental monitoring data collected from 1983 through 1994 during DU testing. Three exposure scenarios were evaluated for potential adverse effects to human health: an occasional use scenario and two farming scenarios. Human exposure was minimal from occasional use, but significant risk were predicted from the farming scenarios when contaminated groundwater was used by site occupants. The human health risk assessments do not consider the significant risk posed by accidents with unexploded ordnance. Exposures of white-tailed deer to DU were also estimated in this study, and exposure rates result in no significant increase in either toxicological or radiological risks. The results of this study indicate that remediation of the DU impact area would not substantially reduce already low risks to humans and the ecosystem, and that managed access to JPG is a reasonable model for future land use options.

  8. Multicompartment kinetic models for the metabolism of americium, plutonium and uranium in rats

    International Nuclear Information System (INIS)

    Sontag, W.

    1986-01-01

    To examine the kinetic behaviour of americium, plutonium and uranium in male and female rats, an extended mammillary model has been developed, composed of 10 compartments connected with 17 linear transfer coefficients. The 10 compartments describe the behaviour of the three nuclides in the blood, skeleton, liver and kidney; the remaining activity is assigned to one residual organ. Each organ is divided into two compartments, short- and long-term. In the skeleton the short-term compartment has been assumed to be the bone surface and marrow, and the long-term compartment the deep bone; in the liver, evidence suggests that the short-term compartment is physiologically associated with lysosomes and the long-term compartment identical with telolysosomes. Influence of age, sex and different nuclides on the transfer coefficients and the absorbed radiation dose are discussed. By using the transfer coefficients calculated for intravenous injection, the behaviour of the nuclides in skeleton and liver during continuous intake has been calculated. The behaviour of the three nuclides in skeleton and liver after intravenous injection has also been calculated with the additional assumption that from the fifth day the animals were treated continuously with a chelating agent. (UK)

  9. Model evaluation of seepage from uranium tailings disposal above and below the water table

    International Nuclear Information System (INIS)

    Nelson, R.W.; Meyer, P.R.; Oberlander, P.L.; Sneider, S.C.; Mayer, D.W.; Reisenauer, A.E.

    1983-03-01

    Model simulations identify the rate and amount of leachate released to the environment if disposed uranium mill tailings come into contact with ground water or if seepage from tailings reaches ground water. In this study, simulations of disposal above and below the water table, with various methods of leachate control, were compared. Three leachate control methods were used in the comparisons: clay bottom liners; stub-sidewall clay liners; and tailings drains with sumps, with the effluent pumped back from the sumps. The best leachate control for both above and below the water table is a combination of the three methods. The combined methods intercept up to 80% of the leachate volume in pits above the water table and intercept essentially all of the leachate in pits below the water table. Effluent pumping, however, requires continuous energy costs and an alternative method of disposal for the leachate that cannot be reused as makeup water in the mill process. Without the drains or effluent pumping, the clay bottom liners have little advantage in terms of the total volume of leachate lost. The clay liners do reduce the rate of leachate flow to the ground water, but the flow continues for a longer time. The buffering, sorption, and chemical reactions of the leachate passing directly through the liner are also advantages of the liner

  10. Groundwater contamination from an inactive uranium mill tailings pile. 2. Application of a dynamic mixing model

    International Nuclear Information System (INIS)

    Narashimhan, T.N.; White, A.F.; Tokunaga, T.

    1986-01-01

    At Riverton, Wyoming, low pH process waters from an abandoned uranium mill tailings pile have been infiltrating into and contaminating the shallow water table aquifer. The contamination process has been governed by transient infiltration rates, saturated-unsaturated flow, as well as transient chemical reactions between the many chemical species present in the mixing waters and the sediments. In the first part of this two-part series the authors presented field data as well as an interpretation based on a static mixing models. As an upper bound, the authors estimated that 1.7% of the tailings water had mixed with the native groundwater. In the present work they present the results of numerical investigation of the dynamic mixing process. The model, DYNAMIX (DYNamic MIXing), couples a chemical speciation algorithm, PHREEQE, with a modified form of the transport algorithm, TRUMP, specifically designed to handle the simultaneous migration of several chemical constituents. The overall problem of simulating the evolution and migration of the contaminant plume was divided into three sub problems that were solved in sequential stages. These were the infiltration problem, the reactive mixing problem, and the plume-migration problem. The results of the application agree reasonably with the detailed field data. The methodology developed in the present study demonstrates the feasibility of analyzing the evolution of natural hydrogeochemical systems through a coupled analysis of transient fluid flow as well as chemical reactions. It seems worthwhile to devote further effort toward improving the physicochemical capabilities of the model as well as to enhance its computational efficiency

  11. Model investigations for trace analysis of iodine, uranium, and technetium in saturated sodium chloride leaching solutions of stored radioactive waste

    International Nuclear Information System (INIS)

    Jegle, U.

    1989-02-01

    This paper describes the development of a time and cost saving chromatographic technique, which allows the matrix to be separated and the most important species to be analyzed in a leaching solution of vitrified radioactive waste. Uranium, iodine, and technetium were chosen for the model technique to be elaborated. In a first step, iodide and pertechnetate were separated from the matrix by the strongly basic AG 1X 8 anion exchange resin and then separated from each other by selective elution. The uranyl ions eluted with the sodium chloride matrix were separated from the excess of sodium chloride in a second step, again by adsorption to the strongly basic resin. The ion-selective electrode was found to be a suitable tool for iodide analysis. Pertechnetate was analysed by means of liquid scintillation. Uranium was determined by ICP-AES. (orig./RB) [de

  12. Assessment of current atomic scale modelling methods for the investigation of nuclear fuels under irradiation: Example of uranium dioxide

    International Nuclear Information System (INIS)

    Bertolus, M.; Freyss, M.; Krack, M.; Devanathan, R.

    2015-01-01

    We focus here on the assessment of the description of interatomic interactions in uranium dioxide using, on the one hand, electronic structure methods, in particular in the Density Functional Theory (DFT) framework, and on the other hand, empirical potential methods. These two types of methods are complementary, the former enabling results to be obtained from a minimal amount of input data and further insight into the electronic and magnetic properties to be achieved, while the latter are irreplaceable for studies where a large number of atoms need to be considered. We consider basic properties as well as specific ones, which are important for the description of nuclear fuel under irradiation. These are especially energies, which are the main data passed on to higher scale models. For this exercise, we limit ourselves to uranium dioxide (UO 2 ) because of the extensive amount of studies available on this system. (authors)

  13. Cytotoxic and phenotypic effects of uranium and lead on osteoblastic cellular models

    International Nuclear Information System (INIS)

    Milgram, S.

    2008-04-01

    This study is involved in the evaluation of bio-hazard associated with the use of uranium in nuclear activities and industrial research. The uranium, known in the literature as potentially carcinogenic or toxic for reproduction, can become a public health problem with the views of the various possibilities of human infections (military of the Gulf War, Finnish populations exposed to drinking water contaminated by example). The skeleton represents the organ of long-term storage of uranium and can be a target of its toxicity. Lead sharing this way of fixing in the bone matrix and have the same adverse effects on bone formation. The osteoblasts, cells responsible in bone formation, are specific targets of these two metals. The aim of this study was to evaluate the effects of acute toxicity of speciation controlled uranium and lead on osteoblasts culture. The intracellular accumulation, distribution and speciation were then studied to explain the observed toxicity. A cell death and phenotypic disorder were highlighted. The speciation is seen as crucial in biological effects of these metals. The most toxic species of both metals have been identified. The accumulation or cell distribution could not alone explain the impact of speciation on the toxicity observed. However, a phenomenon of intracellular precipitation of uranium and lead has been stressed and could be involved in a detoxification mechanism. (author)

  14. 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.

  15. 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

  16. MUICYCL and MUIFAP: models tracking minor uranium isotopes in the nuclear fuel cycle

    International Nuclear Information System (INIS)

    Blum, S.R.; McLaren, R.A.

    1979-10-01

    Two computer programs have been written to provide information on the buildup of minor uranium isotopes in the nuclear fuel cycle. The Minor Uranium Isotope Cycle Program, MUICYCL, tracks fuel through a multiyear campaign cycle of enrichment, reactor burnup, reprocessing, enrichment, etc. MUICYCL facilities include preproduction stockpiles, U 235 escalation, and calculation of losses. The Minor Uranium Isotope Flowsheet Analyzer Program, MUIFAP, analyzes one minor isotope in one year of an enrichment operation. The formulation of the enrichment cascade, reactors, and reprocessing facility is presented. Input and output descriptions and sample cases are presented. The programs themselves are documented by short descriptions of each routine, flowcharts, definitions of common blocks and variables, and internal documentation. The programs are written in FORTRAN for use in batch mode

  17. A model for beta skin dose estimation due to the use of a necklace with uranium depleted bullets

    International Nuclear Information System (INIS)

    Lavalle Heibron, P.H.; Pérez Guerrero, J.S.; Oliveira, J.F. de

    2015-01-01

    Depleted uranium bullets were use as munitions during the Kuwait – Iraq war and the International Atomic Energy Agency sampling expert’s team found fragments in the environment when the war was over. Consequently, there is a possibility that members of the public, especially children, collects DU fragments and use it, for example, to make a necklace. This paper estimates the beta skin dose to a child that uses a necklace made with a depleted uranium bullet. The theoretical model for dose estimation is based on Loevinguer’s equation with a correction factor adjusted for the maximum beta energy in the range between 0.1 and 2.5 MeV calculated taking into account the International Atomic Energy Agency expected doses rates in air at one meter distance of a point source of 37 GBq, function of the maximum beta energy. The dose rate estimated by this work due to the child use of a necklace with one depleted uranium bullet of 300 g was in good agreement with other results founded in literature. (authors)

  18. Modelling uranium solubilities in aqueous solutions: Validation of a thermodynamic data base for the EQ3/6 geochemical codes

    International Nuclear Information System (INIS)

    Puigdomenech, I.; Bruno, J.

    1988-01-01

    Experimental solubilities of U 4+ and UO 2 2+ that are reported in the literature have been collected. Data on oxides, hydroxides and carbonates have been selected for this work. They include results both at 25 degrees C and at higher temperatures. The literature data have been compared with calculated uranium solubilities obtained with the EQ3/6 geochemical modelling programs and an uranium thermodynamic data base selected for the Swedish nuclear waste management program. This verification/validiation exercise has shown that more experimental data is needed to determine the chemical composition of anionic uranyl hydroxo complexes as well as their equilibrium constants of formation. There is also a need for more solubility data on well characterised alkaline or alkaline-earth uranates. For the uranyl carbonate system, the calculated results agree reasonably well with the experimental literature values, which span over a wide range of pH, (CO 3 2- ) T , CO 2 (g)-pressure, and T. The experimental solubility of UO 2 (s) agrees also well with the EQ3/6 calculations for pH greater than 6. However, in more acidic solutions the experimental solubilities are higher than the calculated values. This is due to the formation of polynuclear hydroxo complexes of uranium, which are not well characterised, and are not included in the thermodynamic data base used in this study. (authors)

  19. Proposition of a new genetic model for the Itataia uranium deposit, state of Ceara, Brazil

    International Nuclear Information System (INIS)

    Saad, S.; Munne, A.I.; Tanaka, A.Y.

    1984-01-01

    The Itataia uranium deposit is located within the central portion of the state of Ceara, being characterized mainly by collophanitic and feldspathic lithologies with some graphite concentrations. The mineralization occurs mainly in collophanitic rocks displaying compact texture and disseminates into marbles and feldspathic rocks. The characterization, within the structural- stratigraphic framework of Itataia, of a supergenic enrichment process through the remobilization and reconcentration of syngenetic uranium in marine carbonate rocks is proposed and discussed through the interpretation of Drill-hoel, geochemical seismic and structural data. (D.M.) [pt

  20. 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

  1. Experimental study and kinetic modeling of the hydro-fluorination of uranium dioxide

    International Nuclear Information System (INIS)

    Pages, Simon

    2014-01-01

    A kinetic study of hydro-fluorination of uranium dioxide was performed between 375 and 475 C under partial pressures of HF between 42 and 720 mbar. The reaction was followed by thermogravimetry in isothermal and isobaric conditions. The kinetic data obtained coupled with a characterization of the powder before, during and after reaction by SEM, EDS, BET and XRD showed that the powder grains of UO 2 are transformed according a model of instantaneous germination, anisotropic growth and internal development. The rate limiting step of the growth process is the diffusion of HF in the UF 4 layer. A mechanism of growth of the UF 4 layer has been proposed. In the temperature and pressure range studied, the reaction is of first order with respect to HF and follows an Arrhenius law. A rate equation was determined and used to perform kinetic simulations which have shown a very good correlation with experience. Coupling of this rate equation with heat and mass transport phenomena allowed to perform simulations at the scale of a powder's agglomerate. They have shown that some structures of agglomerates influence the rate of diffusion of the gases in the porous medium and thereby influence the reaction rate. Finally kinetic simulations on powder's beds and pellets were carried out and compared with experimental rates. The experimental and simulated kinetic curves have the same paces, but improvements in the simulations are needed to accurately predict rates: the coupling between the three scales (grain, agglomerate, oven) would be a good example. (author) [fr

  2. 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.

  3. Modeling the interaction of light intensity, nutrient concentration and uranium toxicity in Lemna minor

    Energy Technology Data Exchange (ETDEWEB)

    Zimmer, E.; Horemans, N.; Vandenhove, H. [Belgian Nuclear Research Centre SCK-CEN (Belgium); Cedergreen, N. [University of Copenhagen (Denmark); Jager, T. [Vrije Universiteit Amsterdam (Netherlands)

    2014-07-01

    focused on (heterotrophic) animals, where usually only one food source with constant composition is taken into account. Reproduction can in most cases be modeled simplistically as continuous production of offspring in the final developmental stage. A DEB model for a (photoautotrophic) plant should take into account both light and nutrients as energy input. Additionally, reproduction takes place differently than in animals (e.g., vegetative reproduction). Until now, no plant model based on DEB has been developed yet. We here present the first DEB model for a plant. It explicitly takes light as an input of energy into account, which enables us to study the interaction of light intensity and radionuclides. As study organism, we chose Lemna minor,because of its advantages of being a relatively simple higher plant. We discuss the interaction of light intensity, nutrient concentration and radionuclides using uranium toxicity as a case study. Document available in abstract form only. (authors)

  4. 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.)

  5. 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)

  6. 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?

  7. 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)

  8. 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.

  9. Modeling Uranium Transport in Koongarra, Australia: The Effect of a Moving Weathering Zone

    NARCIS (Netherlands)

    Leijnse, A.; Weerd, van de H.; Hassanizadeh, S.M.

    2001-01-01

    Natural analogues are an important source of long-term data and may be viewed as naturally occurring experiments that often include processes, phenomena, and scenarios that are important to nuclear waste disposal safety assessment studies. The Koongarra uranium deposit in the Alligator Rivers region

  10. Comparison of spallation-model calculations with experiment on neutron production in uranium

    International Nuclear Information System (INIS)

    Kazaritskij, V.D.; Sibirtsev, A.A.; Stepanov, N.V.

    1988-01-01

    Calculated differential cross-sections for neutrons emitted from a thin uranium target due to 590 MeV protons are compared with experiment. The HETC, HAMLET, D2N2 and EVAP codes were applied. The HAMLET results are most consistent with experiment. 12 refs.; 3 figs

  11. Predictive geochemical modeling of contaminant concentrations in laboratory columns and in plumes migrating from uranium mill tailings waste impoundments

    International Nuclear Information System (INIS)

    Peterson, S.R.; Martin, W.J.; Serne, R.J.

    1986-04-01

    A computer-based conceptual chemical model was applied to predict contaminant concentrations in plumes migrating from a uranium mill tailings waste impoundment. The solids chosen for inclusion in the conceptual model were selected based on reviews of the literature, on ion speciation/solubility calculations performed on the column effluent solutions and on mineralogical characterization of the contacted and uncontacted sediments. The mechanism of adsorption included in the conceptual chemical model was chosen based on results from semiselective extraction experiments and from mineralogical characterization procedures performed on the sediments. This conceptual chemical model was further developed and partially validated in laboratory experiments where assorted acidic uranium mill tailings solutions percolated through various sediments. This document contains the results of a partial field and laboratory validation (i.e., test of coherence) of this chemical model. Macro constituents (e.g., Ca, SO 4 , Al, Fe, and Mn) of the tailings solution were predicted closely by considering their concentrations to be controlled by the precipitation/dissolution of solid phases. Trace elements, however, were generally predicted to be undersaturated with respect to plausible solid phase controls. The concentration of several of the trace elements were closely predicted by considering their concentrations to be controlled by adsorption onto the amorphous iron oxyhydroxides that precipitated

  12. Uranium isotopes and dissolved organic carbon in loess permafrost: Modeling the age of ancient ice

    Science.gov (United States)

    Ewing, Stephanie A.; Paces, James B.; O'Donnell, J.A.; Jorgenson, M.T.; Kanevskiy, M.Z.; Aiken, George R.; Shur, Y.; Harden, Jennifer W.; Striegl, Robert G.

    2015-01-01

    The residence time of ice in permafrost is an indicator of past climate history, and of the resilience and vulnerability of high-latitude ecosystems to global change. Development of geochemical indicators of ground-ice residence times in permafrost will advance understanding of the circumstances and evidence of permafrost formation, preservation, and thaw in response to climate warming and other disturbance. We used uranium isotopes to evaluate the residence time of segregated ground ice from ice-rich loess permafrost cores in central Alaska. Activity ratios of 234U vs. 238U (234U/238U) in water from thawed core sections ranged between 1.163 and 1.904 due to contact of ice and associated liquid water with mineral surfaces over time. Measured (234U/238U) values in ground ice showed an overall increase with depth in a series of five neighboring cores up to 21 m deep. This is consistent with increasing residence time of ice with depth as a result of accumulation of loess over time, as well as characteristic ice morphologies, high segregated ice content, and wedge ice, all of which support an interpretation of syngenetic permafrost formation associated with loess deposition. At the same time, stratigraphic evidence indicates some past sediment redistribution and possibly shallow thaw among cores, with local mixing of aged thaw waters. Using measures of surface area and a leaching experiment to determine U distribution, a geometric model of (234U/238U) evolution suggests mean ages of up to ∼200 ky BP in the deepest core, with estimated uncertainties of up to an order of magnitude. Evidence of secondary coatings on loess grains with elevated (234U/238U) values and U concentrations suggests that refinement of the geometric model to account for weathering processes is needed to reduce uncertainty. We suggest that in this area of deep ice-rich loess permafrost, ice bodies have been preserved from the last glacial period (10–100 ky BP), despite subsequent

  13. 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

  14. Development of a model to optimize global use of nuclear energy considering competition of seawater uranium and reprocessing

    International Nuclear Information System (INIS)

    Undarmaa, Baatarkhuu; Horio, Kenta; Fujii, Yasumasa; Komiyama, Ryoichi

    2017-01-01

    In order to sustain long-term energy security and to mitigate the climate change, nuclear power remains an important baseload option for the global power generation mix. To utilize nuclear power in long-term, some important concerns such as economics, stability of fuel supply and spent fuel amount should be evaluated. Model developed in this study optimizes the global use nuclear power considering such issues. The Model is based on linear programming and calculates the best mix of nuclear reactor types by minimizing the current value of total power generation cost within the target period (next 100 years). Possibility of fuel cycle options such as reprocessing, seawater uranium and thorium utilization are also taken in to account, along with remaining spent fuel and plutonium stock. As result. reprocessing and uranium from seawater become essential part of nuclear fuel cycle in the long run. Amount of stored spent fuel is reduced following the deployment of Fast Breeder Reactor. Also, as an extension of current model, a baseload power generation mix model, which estimates the optimal mix of nuclear and coal-fired power generation will be introduced. (author)

  15. Uranium mining

    International Nuclear Information System (INIS)

    Lange, G.

    1975-01-01

    The winning of uranium ore is the first stage of the fuel cycle. The whole complex of questions to be considered when evaluating the profitability of an ore mine is shortly outlined, and the possible mining techniques are described. Some data on uranium mining in the western world are also given. (RB) [de

  16. Literature review of models for estimating soil erosion and deposition from wind stresses on uranium-mill-tailings covers

    Energy Technology Data Exchange (ETDEWEB)

    Bander, T.J.

    1982-11-01

    Pacific Northwest Laboratory (PNL) is investigating the use of a rock armoring blanket (riprap) to mitigate wind and water erosion of an earthen radon-suppression cover applied to uranium-mill tailings. The mechanics of wind erosion, as well as of soil deposition, are discussed in this report. Several wind erosion models are reviewed to determine if they can be used to estimate the erosion of soil from a mill-tailings cover. One model, developed by W.S. Chepil, contains the most-important factors that describe variables that influence wind erosion. Particular features of other models are also discussed, as well as the application of Chepil's model to a particular tailings pile. For this particular tailings pile, the estimated erosion was almost one inch per year for an unprotected tailings soil surface. Wide variability in the deposition velocity and lack of adequate deposition models preclude reliable estimates of the rate at which airborne particles are deposited.

  17. Literature review of models for estimating soil erosion and deposition from wind stresses on uranium-mill-tailings covers

    International Nuclear Information System (INIS)

    Bander, T.J.

    1982-11-01

    Pacific Northwest Laboratory (PNL) is investigating the use of a rock armoring blanket (riprap) to mitigate wind and water erosion of an earthen radon-suppression cover applied to uranium-mill tailings. The mechanics of wind erosion, as well as of soil deposition, are discussed in this report. Several wind erosion models are reviewed to determine if they can be used to estimate the erosion of soil from a mill-tailings cover. One model, developed by W.S. Chepil, contains the most-important factors that describe variables that influence wind erosion. Particular features of other models are also discussed, as well as the application of Chepil's model to a particular tailings pile. For this particular tailings pile, the estimated erosion was almost one inch per year for an unprotected tailings soil surface. Wide variability in the deposition velocity and lack of adequate deposition models preclude reliable estimates of the rate at which airborne particles are deposited

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

    Energy Technology Data Exchange (ETDEWEB)

    Lovley, Derek R

    2012-12-28

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

  19. Uranium resources

    International Nuclear Information System (INIS)

    1976-01-01

    This is a press release issued by the OECD on 9th March 1976. It is stated that the steep increases in demand for uranium foreseen in and beyond the 1980's, with doubling times of the order of six to seven years, will inevitably create formidable problems for the industry. Further substantial efforts will be needed in prospecting for new uranium reserves. Information is given in tabular or graphical form on the following: reasonably assured resources, country by country; uranium production capacities, country by country; world nuclear power growth; world annual uranium requirements; world annual separative requirements; world annual light water reactor fuel reprocessing requirements; distribution of reactor types (LWR, SGHWR, AGR, HWR, HJR, GG, FBR); and world fuel cycle capital requirements. The information is based on the latest report on Uranium Resources Production and Demand, jointly issued by the OECD's Nuclear Energy Agency (NEA) and the International Atomic Energy Agency. (U.K.)

  20. 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)

  1. Uranium decontamination in Purex second plutonium cycle: An example of solvent extraction modeling

    International Nuclear Information System (INIS)

    Hsu, T.C.

    1986-01-01

    The existing Purex flowsheet used in the second plutonium cycle at the Savannah River Plant (SRP) does not remove uranium from the plutonium stream. To develop new flowsheets for the Purex second plutonium cycle, computer simulation using SEPHIS was used. SEPHIS is an ORNL-developed solvent extraction simulation code. Box-Wilson experimental design was used to select the minimum set of process conditions simulated. The calculated results were plotted into three-dimensional response surfaces by SAS/Graph (statistical analysis systems). These surfaces provide a broad and complete overview of the responses. Specific ranges of key variables were then investigated. The second series of process simulations identified flowsheets that provide high uranium decontamination while meeting all other key process requirements. The proposed flowsheet consists of modifying the existing 2B bank flowsheet by relocating the feed, increasing the extractant acidity, and adding a scrub stream. The nuclear safety issue was also examined

  2. 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)

  3. Uranium toxicology

    International Nuclear Information System (INIS)

    Ferreyra, Mariana D.; Suarez Mendez, Sebastian

    1997-01-01

    In this paper are presented the methods and procedures optimized by the Nuclear Regulatory Authority (ARN) for the determination of: natural uranium mass, activity of enriched uranium in samples of: urine, mucus, filters, filter heads, rinsing waters and Pu in urine, adopted and in some cases adapted, by the Environmental Monitoring and Internal Dosimetry Laboratory. The analyzed material corresponded to biological and environmental samples belonging to the staff professionally exposed that work in plants of the nuclear fuel cycle. For a better comprehension of the activities of this laboratory, it is included a brief description of the uranium radiochemical toxicity and the limits internationally fixed to preserve the workers health

  4. 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

  5. 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

  6. 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.)

  7. Rossing uranium

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    In this article the geology of the deposits of the Rossing uranium mine in Namibia is discussed. The planning of the open-pit mining, the blasting, drilling, handling and the equipment used for these processes are described

  8. 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

  9. 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)

  10. Uranium loans

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    When NUEXCO was organized in 1968, its founders conceived of a business based on uranium loans. The concept was relatively straightforward; those who found themselves with excess supplies of uranium would deposit those excesses in NUEXCO's open-quotes bank,close quotes and those who found themselves temporarily short of uranium could borrow from the bank. The borrower would pay interest based on the quantity of uranium borrowed and the duration of the loan, and the bank would collect the interest, deduct its service fee for arranging the loan, and pay the balance to those whose deposits were borrowed. In fact, the original plan was to call the firm Nuclear Bank Corporation, until it was discovered that using the word open-quotes Bankclose quotes in the name would subject the firm to various US banking regulations. Thus, Nuclear Bank Corporation became Nuclear Exchange Corporation, which was later shortened to NUEXCO. Neither the nuclear fuel market nor NUEXCO's business developed quite as its founders had anticipated. From almost the very beginning, the brokerage of uranium purchases and sales became a more significant activity for NUEXCO than arranging uranium loans. Nevertheless, loan transactions have played an important role in the international nuclear fuel market, requiring the development of special knowledge and commercial techniques

  11. 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)

  12. Heat processing of gels into sintered uranium dioxide modelled by thermal analysis. I

    International Nuclear Information System (INIS)

    Landspersky, H.; Urbanek, V.

    1979-01-01

    Thermoanalytical methods were used for investigating the processes of air drying and calcination of gels prepared by internal gelation of uranyl nitrate, urea and urotropine solutions at 90 degC. The gels were dried in air at room temperature, at 220 degC in a controlled atmosphere or by azeotropic distillation with CCl 4 . The course of thermal decomposition of the gel depends not only on the drying method used but also on the medium in which the drying process takes place. If the drying is carried out so as to produce a macroporous structure after the elimination of most of the water, ammonia and possibly other gelation by-products and non-reacted gelating agents, the resulting gels can be further processed by calcination, reduction and sintering, thus obtaining compact undamaged spheres of sintered uranium dioxide. Dilatometric analysis generated of uranium trioxide gels showed that the transformation of UO 3 to U 3 O 8 generated another intermediate thermal decomposition product showing a change in dimensions at temperatures of about 520 degC and a change in colour. This phenomenon is analogous to the decomposition of UO 3 prepared by thermal decomposition of α-UO 3 .2H 2 O involving a change in weight producing the UOsub(3-x) compound or a phase transformation with a change in colour; the structural conversion cannot be identified by X-ray structural analysis. (author)

  13. 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.)

  14. 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.

  15. Box-Behnken design in modeling of solid-phase tea waste extraction for the removal of uranium from water samples

    International Nuclear Information System (INIS)

    Khajeh, Mostafa; Jahanbin, Elham; Ghaffari-Moghaddam, Mansour; Moghaddam, Zahra Safaei; Bohlooli, Mousa

    2015-01-01

    In this study, the solid-phase tea waste procedure was used for separation, preconcentration and determination of uranium from water samples by UV-Vis spectrophotometer. In addition, Box-Behnken experimental design was employed to investigated the influence of six variables including pH, mass of adsorbent, eluent volume, amount of 1-(2-pyridylazo)-2-naphthol (PAN); and sample and eluent flow rates on the extraction of analyte. High determination coefficient (R 2 ) of 0.972 and adjusted-R 2 of 0.943 showed the satisfactory adjustment of the polynomial regression model. This method was used for the extraction of uranium from real water samples.

  16. Uranium mining

    International Nuclear Information System (INIS)

    2008-01-01

    Full text: The economic and environmental sustainability of uranium mining has been analysed by Monash University researcher Dr Gavin Mudd in a paper that challenges the perception that uranium mining is an 'infinite quality source' that provides solutions to the world's demand for energy. Dr Mudd says information on the uranium industry touted by politicians and mining companies is not necessarily inaccurate, but it does not tell the whole story, being often just an average snapshot of the costs of uranium mining today without reflecting the escalating costs associated with the process in years to come. 'From a sustainability perspective, it is critical to evaluate accurately the true lifecycle costs of all forms of electricity production, especially with respect to greenhouse emissions, ' he says. 'For nuclear power, a significant proportion of greenhouse emissions are derived from the fuel supply, including uranium mining, milling, enrichment and fuel manufacture.' Dr Mudd found that financial and environmental costs escalate dramatically as the uranium ore is used. The deeper the mining process required to extract the ore, the higher the cost for mining companies, the greater the impact on the environment and the more resources needed to obtain the product. I t is clear that there is a strong sensitivity of energy and water consumption and greenhouse emissions to ore grade, and that ore grades are likely to continue to decline gradually in the medium to long term. These issues are critical to the current debate over nuclear power and greenhouse emissions, especially with respect to ascribing sustainability to such activities as uranium mining and milling. For example, mining at Roxby Downs is responsible for the emission of over one million tonnes of greenhouse gases per year and this could increase to four million tonnes if the mine is expanded.'

  17. Analysis and exploitation of bacterial population from natural uranium-rich soils: selection of a model specie

    International Nuclear Information System (INIS)

    Mondani, L.

    2010-01-01

    It is well known that soils play a key role in controlling the mobility of toxic metals and this property is greatly influenced by indigenous bacterial communities. This study has been conducted on radioactive and controls soils, collected in natural uraniferous areas (Limousin). A physico-chemical and mineralogical analysis of soils samples was carried out.The structure of bacterial communities was estimated by Denaturing Gradient Gel Electrophoresis (DGGE). The community structure is remarkably more stable in the uranium-rich soils than in the control ones, indicating that uranium exerts a high selection from the soils was constructed and screened for uranium resistance in order to study bacteria-uranium interactions. Scanning electron microscopy revealed that a phylo-genetically diverse set of uranium-resistant species ware able to chelate uranium at the cell surface. (author) [fr

  18. 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

  19. Uranium enrichment

    International Nuclear Information System (INIS)

    Rae, H.K.; Melvin, J.G.

    1988-06-01

    Canada is the world's largest producer and exporter of uranium, most of which is enriched elsewhere for use as fuel in LWRs. The feasibility of a Canadian uranium-enrichment enterprise is therefore a perennial question. Recent developments in uranium-enrichment technology, and their likely impacts on separative work supply and demand, suggest an opportunity window for Canadian entry into this international market. The Canadian opportunity results from three particular impacts of the new technologies: 1) the bulk of the world's uranium-enrichment capacity is in gaseous diffusion plants which, because of their large requirements for electricity (more than 2000 kW·h per SWU), are vulnerable to competition from the new processes; 2) the decline in enrichment costs increases the economic incentive for the use of slightly-enriched uranium (SEU) fuel in CANDU reactors, thus creating a potential Canadian market; and 3) the new processes allow economic operation on a much smaller scale, which drastically reduces the investment required for market entry and is comparable with the potential Canadian SEU requirement. The opportunity is not open-ended. By the end of the century the enrichment supply industry will have adapted to the new processes and long-term customer/supplier relationships will have been established. In order to seize the opportunity, Canada must become a credible supplier during this century

  20. 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

  1. Assessment of uranium and selenium speciation in human and bacterial biological models to probe changes in their structural environment

    Energy Technology Data Exchange (ETDEWEB)

    Avoscan, L.; Milgram, S.; Untereiner, G.; Collins, R.; Khodja, H.; Carriere, M.; Gouget, B. [Lab. Pierre Sue, CEA-CNRS UMR 9956, CEA/Saclay, Gif-sur-Yvette (France); Coves, J. [Inst. de Biologie Structurale - J.-P. Ebel, Lab. des Proteines Membranaires, Grenoble (France); Hazemann, J.L. [Lab. de Geophysique Interne et Tectonopbysique, UMR CNRS/Univ. Joseph Fourier, Saint-Martin-D' Heres (France)

    2009-07-01

    This study illustrates the potential of physicochemical techniques to speciate uranium (U) and selenium (Se) in biological samples. Speciation, defined he0re as the study of structural environment, of both toxic elements, was characterized at several levels in biological media and directly in human cells or bacteria once the metal(loid)s were internalized. External speciation that is extracellular speciation in culture media was predicted by thermodynamic equilibrium computer modelling using the JChess software and validated by spectroscopic measurements (XANES and EXAFS). Internal speciation that is intracellular speciation in eukaryotic and prokaryotic cells was studied in vitro with a soil bacterium Cupriavidus metallidurans CH34 and ROS 17/2.8 osteoblasts, human cells responsible for bone formation. XANES, EXAFS, HPLC-ICP-MS and SDS-PAGE coupled to particle induced X-ray emission (PIXE) permitted the identification and quantification of complexes formed with organic or inorganic molecules and/or larger proteins. (orig.)

  2. Assessment of uranium and selenium speciation in human and bacterial biological models to probe changes in their structural environment

    International Nuclear Information System (INIS)

    Avoscan, L.; Milgram, S.; Untereiner, G.; Collins, R.; Khodja, H.; Carriere, M.; Gouget, B.; Coves, J.; Hazemann, J.L.

    2009-01-01

    This study illustrates the potential of physicochemical techniques to speciate uranium (U) and selenium (Se) in biological samples. Speciation, defined he0re as the study of structural environment, of both toxic elements, was characterized at several levels in biological media and directly in human cells or bacteria once the metal(loid)s were internalized. External speciation that is extracellular speciation in culture media was predicted by thermodynamic equilibrium computer modelling using the JChess software and validated by spectroscopic measurements (XANES and EXAFS). Internal speciation that is intracellular speciation in eukaryotic and prokaryotic cells was studied in vitro with a soil bacterium Cupriavidus metallidurans CH34 and ROS 17/2.8 osteoblasts, human cells responsible for bone formation. XANES, EXAFS, HPLC-ICP-MS and SDS-PAGE coupled to particle induced X-ray emission (PIXE) permitted the identification and quantification of complexes formed with organic or inorganic molecules and/or larger proteins. (orig.)

  3. Uranium sorption to natural substrates-insights provided by isotope exchange, selective extraction and surface complexation modelling approaches

    International Nuclear Information System (INIS)

    Waite, T.D.; Payne T.E.; Davis, J.A.

    1993-01-01

    An extensive experimental program has been conducted over the last three years into the interaction of U(VI) with both single oxides and clays and complex natural substrates from the weathered zone in the vicinity of a uranium ore body in northern Australia. While iron oxides have frequently been considered to account for much of the uptake on such natural substrates, the results of laboratory open-quotes pH edgeclose quotes studies and of isotope exchange and selective extraction studies suggest that other phases must also play a significant role in controlling the partitioning of U(VI) between solid and solution phases. Supporting studies on kaolinite, the dominant clay in this system, provide insight into the most appropriate method of modelling the interaction of U(VI) with these natural substrates. The problems still remaining in adequately describing sorption of radionuclides and trace elements to complex natural substrates are discussed

  4. 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.

  5. Uranium update

    International Nuclear Information System (INIS)

    Steane, R.

    1997-01-01

    This paper is about the current uranium mining situation, especially that in Saskatchewan. Canada has a unique advantage with the Saskatchewan uranium deposits. Making the most of this opportunity is important to Canada. The following is reviewed: project development and the time and capital it takes to bring a new project into production; the supply and demand situation to show where the future production fits into the world market; and our foreign competition and how we have to be careful not to lose our opportunity. (author)

  6. Uranium mineralization and unconformities: how do they correlate? - A look beyond the classic unconformity-type deposit model?

    Science.gov (United States)

    Markwitz, Vanessa; Porwal, Alok; Campbell McCuaig, T.; Kreuzer, Oliver P.

    2010-05-01

    Uranium deposits are usually classified based on the characteristics of their host rocks and geological environments (Dahlkamp, 1993; OECD/NEA Red Book and IAEA, 2000; Cuney, 2009). The traditional unconformity-related deposit types are the most economical deposits in the world, with the highest grades amongst all uranium deposit types. In order to predict undiscovered uranium deposits, there is a need to understand the spatial association of uranium mineralization with structures and unconformities. Hydrothermal uranium deposits develop by uranium enriched fluids from source rocks, transported along permeable pathways to their depositional environment. Unconformities are not only separating competent from incompetent sequences, but provide the physico-chemical gradient in the depositional environment. They acted as important fluid flow pathways for uranium to migrate not only for surface-derived oxygenated fluids, but also for high oxidized metamorphic and magmatic fluids, dominated by their geological environment in which the unconformities occur. We have carried out comprehensive empirical spatial analyses of various types of uranium deposits in Australia, and first results indicate that there is a strong spatial correlation between unconformities and uranium deposits, not only for traditional unconformity-related deposits but also for other styles. As a start we analysed uranium deposits in Queensland and in particular Proterozoic metasomatic-related deposits in the Mount Isa Inlier and Late Carboniferous to Early Permian volcanic-hosted uranium occurrences in Georgetown and Charters Towers Regions show strong spatial associations with contemporary and older unconformities. The Georgetown Inlier in northern Queensland consists of a diverse range of rocks, including Proterozoic and early Palaeozoic metamorphic rocks and granites and late Palaeozoic volcanic rocks and related granites. Uranium-molybdenum (+/- fluorine) mineralization in the Georgetown inlier

  7. Long term contaminant migration and impacts from uranium mill tailings. Comparison of computer models using a hypothetical dataset

    International Nuclear Information System (INIS)

    Camus, H.

    1995-11-01

    The Uranium Mill Tailings Working Group of BIOMOVS II was initiated in Vienna in 1991 with the primary objective of comparing models which can be used to assess the long term impact of radioactive releases from uranium mill tailings, involving multiple pathways, multiple contaminants and multiple environmental receptors. A secondary objective was to examine how these models can be used to assess the fate of stable toxic elements. This is an interim report of the Working Group describing: development of a basic scenario describing a tailings system; application of models in deterministic calculations of contaminant concentrations in biosphere media, and related radiation doses, contaminant intakes and health risks; comparison of model results and review of the modelling. A hypothetical scenario has been developed for contaminant releases from a uranium mill tailings facility. The assumptions for the tailings facility and its environs have been chosen to facilitate the evaluation of potentially important processes incorporated into models. The site description is therefore idealised and does not represent any particular facility or type of facility. Atmospheric and groundwater release source terms have been chosen to facilitate comparison of models and should not be considered realistic. The time and effort taken over derivation of the scenario description and the associated preliminary modelling has been an important and valuable learning exercise. It also reflects the importance of gaining a clear picture of what is being modelled so that comparisons of model results are meaningful. Work within the exercise has contributed to new model development and to improvements and extensions to existing models. The scenario is a simplified description of a real facility and the releases which might occur. No allowance has been made for engineered features on the tailings disposal system which might reduce releases. The source terms have been chosen so as to test the models

  8. Long term contaminant migration and impacts from uranium mill tailings. Comparison of computer models using a hypothetical dataset

    Energy Technology Data Exchange (ETDEWEB)

    Camus, H [CEA Centre d' Etudes Nucleaires de Fontenay-aux-Roses (France). Inst. de Protection et de Surete Nucleaire; and others

    1995-11-01

    The Uranium Mill Tailings Working Group of BIOMOVS II was initiated in Vienna in 1991 with the primary objective of comparing models which can be used to assess the long term impact of radioactive releases from uranium mill tailings, involving multiple pathways, multiple contaminants and multiple environmental receptors. A secondary objective was to examine how these models can be used to assess the fate of stable toxic elements. This is an interim report of the Working Group describing: development of a basic scenario describing a tailings system; application of models in deterministic calculations of contaminant concentrations in biosphere media, and related radiation doses, contaminant intakes and health risks; comparison of model results and review of the modelling. A hypothetical scenario has been developed for contaminant releases from a uranium mill tailings facility. The assumptions for the tailings facility and its environs have been chosen to facilitate the evaluation of potentially important processes incorporated into models. The site description is therefore idealised and does not represent any particular facility or type of facility. Atmospheric and groundwater release source terms have been chosen to facilitate comparison of models and should not be considered realistic. The time and effort taken over derivation of the scenario description and the associated preliminary modelling has been an important and valuable learning exercise. It also reflects the importance of gaining a clear picture of what is being modelled so that comparisons of model results are meaningful. Work within the exercise has contributed to new model development and to improvements and extensions to existing models. The scenario is a simplified description of a real facility and the releases which might occur. No allowance has been made for engineered features on the tailings disposal system which might reduce releases. The source terms have been chosen so as to test the models

  9. 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

  10. 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

  11. 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)

  12. Uranium mining

    International Nuclear Information System (INIS)

    Cheeseman, E.W.

    1980-01-01

    The international uranium market appears to be currently over-supplied with a resultant softening in prices. Buyers on the international market are unhappy about some of the restrictions placed on sales by the government, and Canadian sales may suffer as a result. About 64 percent of Canada's shipments come from five operating Ontario mines, with the balance from Saskatchewan. Several other properties will be producing within the next few years. In spite of the adverse effects of the Three Mile Island incident and the default by the T.V.A. of their contract, some 3 600 tonnes of new uranium sales were completed during the year. The price for uranium had stabilized at US $42 - $44 by mid 1979, but by early 1980 had softened somewhat. The year 1979 saw the completion of major environmental hearings in Ontario and Newfoundland and the start of the B.C. inquiry. Two more hearings are scheduled for Saskatchewan in 1980. The Elliot Lake uranium mining expansion hearings are reviewed, as are other recent hearings. In the production of uranium for nuclear fuel cycle, environmental matters are of major concern to the industry, the public and to governments. Research is being conducted to determine the most effective method for removing radium from tailings area effluents. Very stringent criteria are being drawn up by the regulatory agencies that must be met by the industry in order to obtain an operating licence from the AECB. These criteria cover seepages from the tailings basin and through the tailings retention dam, seismic stability, and both short and long term management of the tailings waste management area. (auth)

  13. 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.

  14. 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

  15. 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

  16. Modeling non-steady state radioisotope transport in the vadose zone--A case study using uranium isotopes at Pena Blanca, Mexico

    International Nuclear Information System (INIS)

    Ku, T.L.; Luo, S.; Goldstein, S.J.; Murrell, M.T.; Chu, W.L.; Dobson, P.F.

    2009-01-01

    Current models using U- and Th-series disequilibria to study radioisotope transport in groundwater systems mostly consider a steady-state situation. These models have limited applicability to the vadose zone (UZ) where the concentration and migratory behavior of radioisotopes in fluid are often transitory. We present here, as a first attempt of its kind, a model simulating the non-steady state, intermittent fluid transport in vadose layers. It provides quantitative constraints on in-situ migration of dissolved and colloidal radioisotopes in terms of retardation factor and rock-water interaction (or water transit) time. For uranium, the simulation predicts that intermittent flushing in the UZ leads to a linear relationship between reciprocal U concentration and 234 U/ 238 U ratio in percolating waters, with the intercept and slope bearing information on the rates of dissolution and α-recoil of U isotopes, respectively. The general validity of the model appears to be borne out by the measurement of uranium isotopes in UZ waters collected at various times over a period during 1995-2006 from a site in the Pena Blanca mining district, Mexico, where the Nopal I uranium deposit is located. Enhanced 234 U/ 238 U ratios in vadose-zone waters resulting from lengthened non-flushing time as prescribed by the model provide an interpretative basis for using 234 U/ 238 U in cave calcites to reconstruct the regional changes in hydrology and climate. We also provide a theoretical account of the model's potential applications using radium isotopes.

  17. Turbulent precipitation of uranium oxalate in a vortex reactor - experimental study and modelling; Precipitation turbulente d'oxalate d'uranium en reacteur vortex - etude experimentale et modelisation

    Energy Technology Data Exchange (ETDEWEB)

    Sommer de Gelicourt, Y

    2004-03-15

    Industrial oxalic precipitation processed in an un-baffled magnetically stirred tank, the Vortex Reactor, has been studied with uranium simulating plutonium. Modelling precipitation requires a mixing model for the continuous liquid phase and the solution of population balance for the dispersed solid phase. Being chemical reaction influenced by the degree of mixing at molecular scale, that commercial CFD code does not resolve, a sub-grid scale model has been introduced: the finite mode probability density functions, and coupled with a model for the liquid energy spectrum. Evolution of the dispersed phase has been resolved by the quadrature method of moments, first used here with experimental nucleation and growth kinetics, and an aggregation kernel based on local shear rate. The promising abilities of this local approach, without any fitting constant, are strengthened by the similarity between experimental results and simulations. (author)

  18. A Model of Uranium Uptake by Plant Roots Allowing for Root-Induced Changes in the soil.

    Science.gov (United States)

    Boghi, Andrea; Roose, Tiina; Kirk, Guy J D

    2018-03-20

    We develop a model with which to study the poorly understood mechanisms of uranium (U) uptake by plants. The model is based on equations for transport and reaction of U and acids and bases in the rhizosphere around cylindrical plant roots. It allows for the speciation of U with hydroxyl, carbonate, and organic ligands in the soil solution; the nature and kinetics of sorption reactions with the soil solid; and the effects of root-induced changes in rhizosphere pH. A sensitivity analysis showed the importance of soil sorption and speciation parameters as influenced by pH and CO 2 pressure; and of root geometry and root-induced acid-base changes linked to the form of nitrogen taken up by the root. The root absorbing coefficient for U, relating influx to the concentration of U species in solution at the root surface, was also important. Simplified empirical models of U uptake by different plant species and soil types need to account for these effects.

  19. 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.)

  20. 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.

  1. 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

  2. Modelling of contaminant migration in acidic groundwater plumes at uranium tailings impoundments: ADNEUT3

    International Nuclear Information System (INIS)

    Cherry, J.A.; Morin, K.A.; Dubrovsky, N.M.

    1984-06-01

    This report describes the creation and application of ADNEUT3, the latest addition to the ADNEUT (Acid-Drainage NEUTralization) family of computer programs for simulating acid-drainage transport and neutralization. The creation of ADNEUT3 involved the expansion of ADNEUT1 to allow variable input conditions such as changing input solution with time, variable initial amounts of minerals through the simulated streamtube, variable velocities through the streamtube, and variable solubilities for relevant minerals dependent on aqueous chemical composition. Concepts for simulating acid-drainage neutralization are reviewed and ADNEUT3 is then applied to a field-study site of acidic contaminant migration from the Nordic Main uranium-tailings impoundment near Elliot Lake, Ontario. A sensitivity study is first implemented to calibrate ADNEUT3 to the results of the 1979 to 1983 field studies. Then ADNEUT3 is used to define probable past conditions at the site which are not reliably known. In particular, ADNEUT3 is used to help identify: 1) the approximate year when acidic seepage began leaving the tailings impoundment (1966-1967), 2) the past chemical composition of the seepage (somewhat more acidic for a short period of time), and 3) the location of the source area within the tailings for the acidic seepage (near the impoundment dam, close to the field site). Finally, ADNEUT3 is used to predict future contaminant migration. Results indicate that hundreds of years are required under present conditions for the most acidic water with associated high levels of contaminants to migrate about 100 m from the tailings impoundment. The cause of this slow movement is the significant neutralization capacity of the aquifer. If acid production within the tailings decreases in the future, migration rates of contaminants will also decrease

  3. 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)

  4. 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.

  5. 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

  6. 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

  7. 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.

  8. Uranium - what role

    International Nuclear Information System (INIS)

    Grey, T.; Gaul, J.; Crooks, P.; Robotham, R.

    1980-01-01

    Opposing viewpoints on the future role of uranium are presented. Topics covered include the Australian Government's uranium policy, the status of nuclear power around the world, Australia's role as a uranium exporter and problems facing the nuclear industry

  9. Brazilian uranium exploration program

    International Nuclear Information System (INIS)

    Marques, J.P.M.

    1981-01-01

    General information on Brazilian Uranium Exploration Program, are presented. The mineralization processes of uranium depoits are described and the economic power of Brazil uranium reserves is evaluated. (M.C.K.) [pt

  10. Uranium enrichment

    International Nuclear Information System (INIS)

    1991-11-01

    This paper analyzes under four different scenarios the adequacy of a $500 million annual deposit into a fund to pay for the cost of cleaning up the Department of Energy's (DOE) three aging uranium enrichment plants. These plants are located in Oak Ridge, Tennessee; Paducah, Kentucky; and Portsmouth, Ohio. In summary the following was found: A fixed annual $500 million deposit made into a cleanup fund would not be adequate to cover total expected cleanup costs, nor would it be adequate to cover expected decontamination and decommissioning (D and D) costs. A $500 million annual deposit indexed to an inflation rate would likely be adequate to pay for all expected cleanup costs, including D and D costs, remedial action, and depleted uranium costs

  11. Uranium production

    International Nuclear Information System (INIS)

    Spriggs, M.

    1980-01-01

    The balance between uranium supply and demand is examined. Should new resources become necessary, some unconventional sources which could be considered include low-grade extensions to conventional deposits, certain types of intrusive rock, tuffs, and lake and sea-bed sediments. In addition there are large but very low grade deposits in carbonaceous shales, granites, and seawater. The possibility of recovery is discussed. Programmes of research into the feasibility of extraction of uranium from seawater, as a by-product from phosphoric acid production, and from copper leach solutions, are briefly discussed. Other possible sources are coal, old mine dumps and tailings, the latter being successfully exploited commercially in South Africa. The greatest constraints on increased development of U from lower grade sources are economics and environmental impact. It is concluded that apart from U as a by-product from phosphate, other sources are unlikely to contribute much to world requirements in the foreseeable future. (U.K.)

  12. Uranium enrichment

    International Nuclear Information System (INIS)

    1991-08-01

    This paper reports that in 1990 the Department of Energy began a two-year project to illustrate the technical and economic feasibility of a new uranium enrichment technology-the atomic vapor laser isotope separation (AVLIS) process. GAO believes that completing the AVLIS demonstration project will provide valuable information about the technical viability and cost of building an AVLIS plant and will keep future plant construction options open. However, Congress should be aware that DOE still needs to adequately demonstrate AVLIS with full-scale equipment and develop convincing cost projects. Program activities, such as the plant-licensing process, that must be completed before a plant is built, could take many years. Further, an updated and expanded uranium enrichment analysis will be needed before any decision is made about building an AVLIS plant. GAO, which has long supported legislation that would restructure DOE's uranium enrichment program as a government corporation, encourages DOE's goal of transferring AVLIS to the corporation. This could reduce the government's financial risk and help ensure that the decision to build an AVLIS plant is based on commercial concerns. DOE, however, has no alternative plans should the government corporation not be formed. Further, by curtailing a planned public access program, which would have given private firms an opportunity to learn about the technology during the demonstration project, DOE may limit its ability to transfer AVLIS to the private sector

  13. 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

  14. Development and testing of 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)

    1983-01-01

    This report deals with secondary geochemical dispersion in a subarct environment (Ilimaussaq Complex, south Greenland) of uranium and accompanying elements around a U deposit in which the refractory mineral steenstrupine is the main U-bearing mineral. Weathering profiles, including soils, and sediments in rivers, lakes and fjords have been sampled and studied. Chemical weathering is not well developed. The coarse-grained agpaitic nepheline syenites of the Ilimaussaq Complex are covered by debris of crumbling material and practically without vegetation, but soil profiles and vegetation are developed on glacial deposits and on weathered basement granite. 480 samples have been analysed for 22 elements and the data treated by multivariable analyses with main emphasis on principal component analysis. It was found that U and the other elements have been dispersed during weathering. The sediments in rivers and fjords show low correlation of U with those elements that are associated with U Ilimaussaq. Principal component analysis of the total sample materia of soils and lake and river sediments based on 17 elements makes the identification of the area containing the U deposit possible in the first three dimensions. The elements used are those which correlate with Th in this type of deposit. The statistical significance is however low when singlesample populations, as for instance the C-horizons of soils, are used. 41 refs. (EG)

  15. Implementation of the ICRP 66 respiratory tract model: example of occupational exposure to uranium oxides formed in a new laser enrichment process

    International Nuclear Information System (INIS)

    Ansoborlo, E.; Henge-Napoli, M.H.; Hodgson, A.; Stradling, G.N.; Birchall, A.

    1996-01-01

    A new uranium enrichment facility using laser isotopic separation generates aerosols consisting of U metal + UO 2 : with traces of UPON. Results of lung absorption to blood showed that the U metal + UO 2 transportability was appreciably greater than for other industrial forms of UO 2 . Taking into account the new ICRP human respiratory tract model, the data were used as a basis for assessing the dose coefficient, for the dust sampled at the workplace. (author)

  16. 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

  17. 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

  18. Comparison of estimation and simulation methods for modeling block 1 of anomaly no.3 in Narigan Uranium mineral deposit

    International Nuclear Information System (INIS)

    Jamali Esfahlan, D.; Madani, H.

    2011-01-01

    Geostatistical methods are applied for modeling the mineral deposits at the final stage of the detailed exploration. By applying the results of these models, the technical and economic feasibility studies are conducted for the deposits. The geostatistical modeling methods are usually consist of estimation and simulation methods. The estimation techniques, such as Kriging, construct spatial relation (geological continuation model) between data, by providing the best unique guesses for unknown features. However, when applying this technique for a grid of drill-holes over a deposit, an obvious discrepancy exists between the real geological features and the Kriging estimation map. Because of the limited number of sampled data applied for Kriging, it could not appear as the same as the real features. Also the spatial continuity estimated by the Kriging maps, are smoother than the real unknown features. On the other hand, the objective of simulation is to provide some functions or sets of variable values, to be compatible with the existing information. This means that the simulated values have an average and the variance similar to the raw data and may even be the same as the measurements. we studied the Anomaly No.3 of Narigan uranium mineral deposit, located in the central Iran region and applied the Kriging estimation and the sequential Gaussian simulation methods, and finally by comparing the results we concluded that the Kriging estimation method is more reliable for long term planning of a mine. Because of the reconstructing random structures, the results of the simulation methods indicate that they could also be applied for short term planning in mine exploitation.

  19. 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

  20. A Model to Reproduce the Response of the Gaseous Fission Product Monitor (GFPM) in a CANDU{sup R} 6 Reactor (An Estimate of Tramp Uranium Mass in a Candu Core)

    Energy Technology Data Exchange (ETDEWEB)

    Mostofian, Sara; Boss, Charles [AECL Atomic Energy of Canada Limited, 2251 Speakman Drive, Mississauga Ontario L5K 1B2 (Canada)

    2008-07-01

    In a Canada Deuterium Uranium (Candu) reactor, the fuel bundles produce gaseous and volatile fission products that are contained within the fuel matrix and the welded zircaloy sheath. Sometimes a fuel sheath can develop a defect and release the fission products into the circulating coolant. To detect fuel defects, a Gaseous Fission Product Monitoring (GFPM) system is provided in Candu reactors. The (GFPM) is a gamma ray spectrometer that measures fission products in the coolant and alerts the operator to the presence of defected fuel through an increase in measured fission product concentration. A background fission product concentration in the coolant also arises from tramp uranium. The sources of the tramp uranium are small quantities of uranium contamination on the surfaces of fuel bundles and traces of uranium on the pressure tubes, arising from the rare defected fuel element that released uranium into the core. This paper presents a dynamic model that reproduces the behaviour of a GFPM in a Candu 6 plant. The model predicts the fission product concentrations in the coolant from the chronic concentration of tramp uranium on the inner surface of the pressure tubes (PT) and the surface of the fuel bundles (FB) taking into account the on-power refuelling system. (authors)

  1. Uranium price forecasting methods

    International Nuclear Information System (INIS)

    Fuller, D.M.

    1994-01-01

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

  2. 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

  3. 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)

  4. 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

  5. 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.

  6. 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

  7. Box-Behnken design in modeling of solid-phase tea waste extraction for the removal of uranium from water samples

    Energy Technology Data Exchange (ETDEWEB)

    Khajeh, Mostafa; Jahanbin, Elham; Ghaffari-Moghaddam, Mansour; Moghaddam, Zahra Safaei [Zabol Univ. (Iran, Islamic Republic of). Dept. of Chemistry; Bohlooli, Mousa [Zabol Univ. (Iran, Islamic Republic of). Dept. of Biology

    2015-07-01

    In this study, the solid-phase tea waste procedure was used for separation, preconcentration and determination of uranium from water samples by UV-Vis spectrophotometer. In addition, Box-Behnken experimental design was employed to investigated the influence of six variables including pH, mass of adsorbent, eluent volume, amount of 1-(2-pyridylazo)-2-naphthol (PAN); and sample and eluent flow rates on the extraction of analyte. High determination coefficient (R{sup 2}) of 0.972 and adjusted-R{sup 2} of 0.943 showed the satisfactory adjustment of the polynomial regression model. This method was used for the extraction of uranium from real water samples.

  8. Acid rock drainage in the uranium mining and milling site of Pocos de Caldas, Brazil -- duration assessment, pollutant generation modelling and remediation strategies

    International Nuclear Information System (INIS)

    Fernandes, H.M.; Franklin, M.R.

    2002-01-01

    This geochemical modeling work was carried out to simulate the acid drainage generation from one of the waste-rock piles at the Pocos de Caldas uranium mining site. The mathematical code STEADQYL was used. The estimated results were in good agreement for sulphate and uranium concentrations and the duration of the acid water generation was estimated to be about 500 years. The effect of covering the dump with a material that minimized oxygen diffusion was assessed. Projections indicated that covering the dump with a 1.0 m thickness of a material (like clay), which had an oxygen diffusion coefficient of 10 9 m 2 ·s 1 , would reduce the pollutant concentrations to acceptable values. The estimated cost, when using this strategy, would be about US $10 million. (author)

  9. Integrating Apparent Conductance in Resistivity Sounding to Constrain 2D Gravity Modeling for Subsurface Structure Associated with Uranium Mineralization across South Purulia Shear Zone, West Bengal, India

    Directory of Open Access Journals (Sweden)

    Arkoprovo Biswas

    2014-01-01

    Full Text Available South Purulia Shear Zone (SPSZ is an important area for the prospect of uranium mineralization and no detailed geophysical investigations have been carried out in this region. To delineate the subsurface structure in the present area, vertical electrical soundings using Schlumberger array and gravity survey were carried out along a profile perpendicular to the SPSZ. Apparent conductance in the subsurface revealed a possible connection from SPSZ to Raghunathpur. The gravity model reveals the presence of a northerly dipping low density zone (most likely the shear zone extending up to Raghunathpur under a thin cover of granitic schist of Chotanagpur Granite Gneissic Complex (CGGC. The gravity model also depicts the depth of the zone of density low within this shear zone at ~400 m near Raghunathpur village and this zone truncates with a steep slope. Integration of resistivity and gravity study revealed two possible contact zones within this low density zone in the subsurface at depth of 40 m and 200 m. Our study reveals a good correlation with previous studies in Raghunathpur area characterized by medium to high hydro-uranium anomaly. Thus the conducting zone coinciding with the low gravity anomaly is inferred to be a possible uranium mineralized zone.

  10. Evaluation of geological structure and uranium mineralization model in West Lemajung Sector, Kalan Basin, West Kalimantan

    International Nuclear Information System (INIS)

    Ngadenin; Sularto, P.

    2000-01-01

    The fieldwork is based on the data of strike (S0) and schistosity (S1) of cores that could not penetrate the geological structure model and result of observation on some cores has shown that U mineralization veins are not always parallel to S1. The problems were encountered in core drill data to improve the estimation of U resources from indication category to measured category. The purpose of the evaluation is to establish the advisability of geological structure model and U mineralization model which was applied by this time. The research used remapping of geological structure with surface method in the scale of 1:1000. The result of remapping shows the difference of the dipping between new geological structure model and the old model. The dipping of the new model is to South East until vertical and the old model is to North West until vertical and to South East until vertical. Despite the difference between both of them, the substantive of folding system is identical so that the new and old models can be applied in drilling in West Lemajung sector. U mineralization model of remapping result consists of 3 types : type 1 U mineralization lens form with West-East direction and vertical dipping which is associated with tourmaline, type 2 U mineralization filling in the open fractures with West-East direction and 70 o to North dipping and parallel with S1, and type 3 U mineralization fill in opening fractures with N 110 o - 130 o E the direction and 60 o to North East until subvertical dipping while the old model is only one type. It is U mineralization filling in the open fractures with West-East the direction and 70 o to North the dipping and parallel with S1. Because of this significant difference, data collection of drill core must follow the new mineralization model. (author)

  11. 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

  12. 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)

  13. Investigating Uranium Mobility Using Stable Isotope Partitioning of 238U/235U and a Reactive Transport Model

    Science.gov (United States)

    Bizjack, M.; Johnson, T. M.; Druhan, J. L.; Shiel, A. E.

    2015-12-01

    We report a numerical reactive transport model which explicitly incorporates the effectively stable isotopes of uranium (U) and the factors that influence their partitioning in bioactive systems. The model reproduces trends observed in U isotope ratios and concentration measurements from a field experiment, thereby improving interpretations of U isotope ratios as a tracer for U reactive transport. A major factor contributing to U storage and transport is its redox state, which is commonly influenced by the availability of organic carbon to support metal-reducing microbial communities. Both laboratory and field experiments have demonstrated that biogenic reduction of U(VI) fractionates the stable isotope ratio 238U/235U, producing an isotopically heavy solid U(IV) product. It has also been shown that other common reactive transport processes involving U do not fractionate isotopes to a consistently measurable level, which suggests the capacity to quantify the extent of bioreduction occurring in groundwater containing U using 238U/235U ratios. A recent study of a U bioremediation experiment at the Rifle IFRC site (Colorado, USA) applied Rayleigh distillation models to quantify U stable isotope fractionation observed during acetate amendment. The application of these simplified models were fit to the observations only by invoking a "memory-effect," or a constant source of low-concentration, unfractionated U(VI). In order to more accurately interpret the measured U isotope ratios, we present a multi-component reactive transport model using the CrunchTope software. This approach is capable of quantifying the cycling and partitioning of individual U isotopes through a realistic network of transport and reaction pathways including reduction, oxidation, and microbial growth. The model incorporates physical heterogeneity of the aquifer sediments through zones of decreased permeability, which replicate the observed bromide tracer, major ion chemistry, U concentration, and U

  14. Uranium enrichment

    International Nuclear Information System (INIS)

    Mohrhauer, H.

    1982-01-01

    The separation of uranium isotopes in order to enrich the fuel for light water reactors with the light isotope U-235 is an important part of the nuclear fuel cycle. After the basic principals of isotope separation the gaseous diffusion and the centrifuge process are explained. Both these techniques are employed on an industrial scale. In addition a short review is given on other enrichment techniques which have been demonstrated at least on a laboratory scale. After some remarks on the present situation on the enrichment market the progress in the development and the industrial exploitation of the gas centrifuge process by the trinational Urenco-Centec organisation is presented. (orig.)

  15. 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.

  16. Modeling conversion of ammonium diuranate (ADU) into uranium dioxide (UO{sub 2}) powder

    Energy Technology Data Exchange (ETDEWEB)

    Hung, Nguyen Trong; Thuan, Le Ba [Institute for Technology of Radioactive and Rare Elements (ITRRE), 48 Lang Ha, Dong Da, Ha Noi (Viet Nam); Khoai, Do Van [Institute for Technology of Radioactive and Rare Elements (ITRRE), 48 Lang Ha, Dong Da, Ha Noi (Viet Nam); Current Postdoctoral Fellow at Tokai Reprocessing Technology Development Center, Japan Atomic Energy Agency (JAEA), 4-33 Tokaimura, Nakagun, Ibaraki, 319-1194 (Japan); Lee, Jin-Young, E-mail: jylee@kigam.re.kr [Convergence Research Center for Development of Mineral Resources (DMR), Korea Institute of Geoscience and Mineral Resources (KIGAM), Daejeon, 34132 (Korea, Republic of); Jyothi, Rajesh Kumar, E-mail: rkumarphd@kigam.re.kr [Convergence Research Center for Development of Mineral Resources (DMR), Korea Institute of Geoscience and Mineral Resources (KIGAM), Daejeon, 34132 (Korea, Republic of)

    2016-10-15

    In the paper, Brandon mathematical model that describes the relationship between the essential fabrication parameters [reduction temperature (T{sub R}), calcination temperature (T{sub C}), calcination time (t{sub C}) and reduction time (t{sub R})] and specific surface area of ammonium diuranate (ADU)-derived UO{sub 2} powder products was established. The proposed models can be used to predict and control the specific surface area of UO{sub 2} powders prepared through ADU route. Suitable temperatures for conversion of ADU and ammonium uranyl carbonate (AUC) was examined with the proposed model through assessment of the sinterability of UO{sub 2} powders.

  17. 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

  18. Uranium enrichment. Enrichment processes

    International Nuclear Information System (INIS)

    Alexandre, M.; Quaegebeur, J.P.

    2009-01-01

    Despite the remarkable progresses made in the diversity and the efficiency of the different uranium enrichment processes, only two industrial processes remain today which satisfy all of enriched uranium needs: the gaseous diffusion and the centrifugation. This article describes both processes and some others still at the demonstration or at the laboratory stage of development: 1 - general considerations; 2 - gaseous diffusion: physical principles, implementation, utilisation in the world; 3 - centrifugation: principles, elementary separation factor, flows inside a centrifuge, modeling of separation efficiencies, mechanical design, types of industrial centrifuges, realisation of cascades, main characteristics of the centrifugation process; 4 - aerodynamic processes: vortex process, nozzle process; 5 - chemical exchange separation processes: Japanese ASAHI process, French CHEMEX process; 6 - laser-based processes: SILVA process, SILMO process; 7 - electromagnetic and ionic processes: mass spectrometer and calutron, ion cyclotron resonance, rotating plasmas; 8 - thermal diffusion; 9 - conclusion. (J.S.)

  19. 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.

  20. Field-scale model for the natural attenuation of uranium at the Hanford 300 area using high performance computing

    Energy Technology Data Exchange (ETDEWEB)

    Lichtner, Peter C [Los Alamos National Laboratory; Hammond, Glenn E [PNNL

    2009-01-01

    Three-dimensional reactive flow and transport simulations are carried out to better understand the persistence of uranium [U(VI)] at the Hanford 300 Area bordering the Columbia River. The massively parallel code PFLOTRAN developed under a DOE SciDAC-2 project is employed in the simulations. The calculations were carried out on 4096 processor cores on ORNL's Jaguar XT4 & 5 Cray supercomputers with run times on the order of 6 hours, equivalent to several years if performed on a single processor with sufficient memory. A new conceptual model is presented for understanding present-day and future attenuation rates of U(VI) at the 300 Area site. Unique to the conceptual model is the recognition of three distinct phases in the evolution of the site corresponding to: (I) initial emplacement of waste; (II) present-day conditions of slow leaching of U(VI) from the Hanford sediments; and (III) the complete removal of non-labile U(VI) from the source region. This work focuses on Phase II. Both labile and non-labile forms of U(VI) are included in the model as sorbed and mineralized forms of U(VI), respectively. The non-labile form plays an important role in providing a long-term source of U(VI) as it slowly leaches out of the Hanford sediment. Rapid fluctuations in the Columbia River stage on hourly, weekly and seasonal time scales are found to' playa major role in determining the migration behavior of U(VI). The calculations demonstrate that U(VI) is released into the Columbia River at a highly fluctuating rate in a ratchet-like behavior with nonzero U(VI) flux occurring only during flow from contaminated sediment into the river. The cumulative flux, however, is found to increase approximately linearly with time. The flow rate and U(VI) flux into the Columbia River predicted by the model is highly sensitive to the value used in the conductance boundary condition at the river-sediment interface. By fitting the conductance to the measured piezometric head at well 399

  1. 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.

  2. Issues in uranium availability

    International Nuclear Information System (INIS)

    Schanz, J.J. Jr.; Adams, S.S.; Gordon, R.L.

    1982-01-01

    The purpose of this publication is to show the process by which information about uranium reserves and resources is developed, evaluated and used. The following three papers in this volume have been abstracted and indexed for the Energy Data Base: (1) uranium reserve and resource assessment; (2) exploration for uranium in the United States; (3) nuclear power, the uranium industry, and resource development

  3. 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.

  4. 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

  5. Uranium processing and properties

    CERN Document Server

    2013-01-01

    Covers a broad spectrum of topics and applications that deal with uranium processing and the properties of uranium Offers extensive coverage of both new and established practices for dealing with uranium supplies in nuclear engineering Promotes the documentation of the state-of-the-art processing techniques utilized for uranium and other specialty metals

  6. Recovering uranium from phosphates

    Energy Technology Data Exchange (ETDEWEB)

    Bergeret, M [Compagnie de Produits Chimiques et Electrometallurgiques Pechiney-Ugine Kuhlmann, 75 - Paris (France)

    1981-06-01

    Processes for the recovery of the uranium contained in phosphates have today become competitive with traditional methods of working uranium sources. These new possibilities will make it possible to meet more rapidly any increases in the demand for uranium: it takes ten years to start working a new uranium deposit, but only two years to build a recovery plant.

  7. 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

  8. 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

  9. Surface complexation modeling of the effects of phosphate on uranium(VI) adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Romero-Gonzalez, M.R.; Cheng, T.; Barnett, M.O. [Auburn Univ., AL (United States). Dept. of Civil Engeneering; Roden, E.E. [Wisconsin Univ., Madison, WI (United States). Dept. of Geology and Geophysics

    2007-07-01

    Previous published data for the adsorption of U(VI) and/or phosphate onto amorphous Fe(III) oxides (hydrous ferric oxide, HFO) and crystalline Fe(III) oxides (goethite) was examined. These data were then used to test the ability of a commonly-used surface complexation model (SCM) to describe the adsorption of U(VI) and phosphate onto pure amorphous and crystalline Fe(III) oxides and synthetic goethite-coated sand, a surrogate for a natural Fe(III)-coated material, using the component additivity (CA) approach. Our modeling results show that this model was able to describe U(VI) adsorption onto both amorphous and crystalline Fe(III) oxides and also goethite-coated sand quite well in the absence of phosphate. However, because phosphate adsorption exhibits a stronger dependence on Fe(III) oxide type than U(VI) adsorption, we could not use this model to consistently describe phosphate adsorption onto both amorphous and crystalline Fe(III) oxides and goethite-coated sand. However, the effects of phosphate on U(VI) adsorption could be incorporated into the model to describe U(VI) adsorption to both amorphous and crystalline Fe(III) oxides and goethite-coated sand, at least for an initial approximation. These results illustrate both the potential and limitations of using surface complexation models developed from pure systems to describe metal/radionuclide adsorption under more complex conditions. (orig.)

  10. Surface complexation modeling of the effects of phosphate on uranium(VI) adsorption

    International Nuclear Information System (INIS)

    Romero-Gonzalez, M.R.; Cheng, T.; Barnett, M.O.; Roden, E.E.

    2007-01-01

    Previous published data for the adsorption of U(VI) and/or phosphate onto amorphous Fe(III) oxides (hydrous ferric oxide, HFO) and crystalline Fe(III) oxides (goethite) was examined. These data were then used to test the ability of a commonly-used surface complexation model (SCM) to describe the adsorption of U(VI) and phosphate onto pure amorphous and crystalline Fe(III) oxides and synthetic goethite-coated sand, a surrogate for a natural Fe(III)-coated material, using the component additivity (CA) approach. Our modeling results show that this model was able to describe U(VI) adsorption onto both amorphous and crystalline Fe(III) oxides and also goethite-coated sand quite well in the absence of phosphate. However, because phosphate adsorption exhibits a stronger dependence on Fe(III) oxide type than U(VI) adsorption, we could not use this model to consistently describe phosphate adsorption onto both amorphous and crystalline Fe(III) oxides and goethite-coated sand. However, the effects of phosphate on U(VI) adsorption could be incorporated into the model to describe U(VI) adsorption to both amorphous and crystalline Fe(III) oxides and goethite-coated sand, at least for an initial approximation. These results illustrate both the potential and limitations of using surface complexation models developed from pure systems to describe metal/radionuclide adsorption under more complex conditions. (orig.)

  11. 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

  12. 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.

  13. Modeling non-steady state radioisotope transport in the vadose zone--A case study using uranium isotopes at Pena Blanca, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ku, T. L.; Luo, S.; Goldstein, S. J.; Murrell, M. T.; Chu, W. L.; Dobson, P. F.

    2009-06-01

    Current models using U- and Th-series disequilibria to study radioisotope transport in groundwater systems mostly consider a steady-state situation. These models have limited applicability to the vadose zone (UZ) where the concentration and migratory behavior of radioisotopes in fluid are often transitory. We present here, as a first attempt of its kind, a model simulating the non-steady state, intermittent fluid transport in vadose layers. It provides quantitative constraints on in-situ migration of dissolved and colloidal radioisotopes in terms of retardation factor and rock-water interaction (or water transit) time. For uranium, the simulation predicts that intermittent flushing in the UZ leads to a linear relationship between reciprocal U concentration and {sup 234}U/{sup 238}U ratio in percolating waters, with the intercept and slope bearing information on the rates of dissolution and {alpha}-recoil of U isotopes, respectively. The general validity of the model appears to be borne out by the measurement of uranium isotopes in UZ waters collected at various times over a period during 1995-2006 from a site in the Pena Blanca mining district, Mexico, where the Nopal I uranium deposit is located. Enhanced {sup 234}U/{sup 238}U ratios in vadose-zone waters resulting from lengthened non-flushing time as prescribed by the model provide an interpretative basis for using {sup 234}U/{sup 238}U in cave calcites to reconstruct the regional changes in hydrology and climate. We also provide a theoretical account of the model's potential applications using radium isotopes.

  14. Modeling non-steady state radioisotope transport in the vadose zone - A case study using uranium isotopes at Peña Blanca, Mexico

    Science.gov (United States)

    Ku, T. L.; Luo, S.; Goldstein, S. J.; Murrell, M. T.; Chu, W. L.; Dobson, P. F.

    2009-10-01

    Current models using U- and Th-series disequilibria to study radioisotope transport in groundwater systems mostly consider a steady-state situation. These models have limited applicability to the vadose zone (UZ) where the concentration and migratory behavior of radioisotopes in fluid are often transitory. We present here, as a first attempt of its kind, a model simulating the non-steady state, intermittent fluid transport in vadose layers. It provides quantitative constraints on in-situ migration of dissolved and colloidal radioisotopes in terms of retardation factor and rock-water interaction (or water transit) time. For uranium, the simulation predicts that intermittent flushing in the UZ leads to a linear relationship between reciprocal U concentration and 234U/ 238U ratio in percolating waters, with the intercept and slope bearing information on the rates of dissolution and α-recoil of U isotopes, respectively. The general validity of the model appears to be borne out by the measurement of uranium isotopes in UZ waters collected at various times over a period during 1995-2006 from a site in the Peña Blanca mining district, Mexico, where the Nopal I uranium deposit is located. Enhanced 234U/ 238U ratios in vadose-zone waters resulting from lengthened non-flushing time as prescribed by the model provide an interpretative basis for using 234U/ 238U in cave calcites to reconstruct the regional changes in hydrology and climate. We also provide a theoretical account of the model's potential applications using radium isotopes.

  15. Na, K, Ca, Mg, and U-series in fossil bone and the proposal of a radial diffusion–adsorption model of uranium uptake

    International Nuclear Information System (INIS)

    Cid, A.S.; Anjos, R.M.; Zamboni, C.B.; Cardoso, R.; Muniz, M.; Corona, A.; Valladares, D.L.

    2014-01-01

    Fossil bones are often the only materials available for chronological reconstruction of important archeological sites. However, since bone is an open system for uranium, it cannot be dated directly and therefore it is necessary to develop models for the U uptake. Hence, a radial diffusion–adsorption (RDA) model is described. Unlike the classic diffusion–adsorption (D–A) model, RDA uses a cylindrical geometry to describe the U uptake in fossil bones. The model was applied across a transverse section of a tibia of an extinct megamammal Macrauchenia patachonica from the La Paz Local Fauna, Montevideo State, Uruguay. Measurements of spatial distribution of Na, K, Ca, and Mg were also performed by neutron activation analysis (NAA). Gamma-ray spectrometric U-series dating was applied to determine the age of the bone sample. From U concentration profile, it was possible to observe the occurrence of a relatively slow and continuous uranium uptake under constant conditions that had not yet reached equilibrium, since the uranium distribution is a ∪-shaped closed-system. Predictions of the RDA model were obtained for a specific geochemical scenario, indicating that the effective diffusion coefficient D/R in this fossil bone is (2.4 ± 0.6)10 −12 cm 2 s −1 . Mean values of Na, K, Ca, and Mg contents along the radial line of the fossil tibia are consistent with the expected behavior for spatial distributions of these mineral elements across a modern bone section. This result indicates that the fossil tibia may have its mineral structure preserved. - Highlights: • The Radial diffusion–adsorption (RDA) model is described. • RDA uses a cylindrical geometry to describe the U uptake in fossil bones. • We show new data for an extinct Macrauchenia patachonica from Uruguay. • Spatial distributions of Na, K, Ca, Mg, and U across a fossil bone section. • Gamma-ray spectrometric U-series dating was applied to determine its age

  16. 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

  17. Angular overlap model analysis of the D 2d crystal field effect in uranium (4+) compounds

    Science.gov (United States)

    Gajek, Z.; Hubert, S.; Krupa, J. C.

    1988-12-01

    Recent interpretations of the D 2d crystal field of U 4+ in β-ThCl 4, α, β-ThBr 4, ThSiO 4 and UCl 4 are discussed in terms of the simplified one-, two- and three-parameter versions of the Angular Overlap Model which are shown to be a handy tool in a trial interpretation of the effect. The variation of the CF parameters with a small D 2 distortion of the coordination is well reproduced by the model.

  18. 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)

  19. Uranium - the world picture

    International Nuclear Information System (INIS)

    Silver, J.M.; Wright, W.J.

    1976-01-01

    The world resources of uranium and the future demand for uranium are discussed. The amount of uranium available depends on the price which users are prepared to pay for its recovery. As the price is increased, there is an incentive to recover uranium from lower grade or more difficult deposits. In view of this, attention is drawn to the development of the uranium industry in Australias

  20. Kinetics of Uranium(VI) Desorption from Contaminated Sediments: Effect of Geochemical Conditions and Model Evaluation

    International Nuclear Information System (INIS)

    Liu, Chongxuan; Shi, Zhenqing; Zachara, John M.

    2009-01-01

    Stirred-flow cell experiments were performed to investigate the kinetics of uranyl (U(VI)) desorption from a contaminated sediment collected from the Hanford 300 Area at the US Department of Energy (DOE) Hanford Site, Washington. Three influent solutions of variable pH, Ca and carbonate concentrations that affected U(VI) aqueous and surface speciation were used under dynamic flow conditions to evaluate the effect of geochemical conditions on the rate of U(VI) desorption. The measured rate of U(VI) desorption varied with solution chemical composition that evolved as a result of thermodynamic and kinetic interactions between the influent solutions and sediment. The solution chemical composition that led to a lower equilibrium U(VI) sorption to the solid phase yielded a faster desorption rate. The experimental results were used to evaluate a multi-rate, surface complexation model (SCM) that has been proposed to describe U(VI) desorption kinetics in the Hanford sediment that contained complex sorbed U(VI) species in mass transfer limited domains. The model was modified and supplemented by including multi-rate, ion exchange reactions to describe the geochemical interactions between the solutions and sediment. With the same set of model parameters, the modified model reasonably well described the evolution of major ions and the rates of U(VI) desorption under variable geochemical and flow conditions, implying that the multi-rate SCM is an effective way to describe U(VI) desorption kinetics in subsurface sediments

  1. Na, K, Ca, Mg, and U-series in fossil bone and the proposal of a radial diffusion-adsorption model of uranium uptake.

    Science.gov (United States)

    Cid, A S; Anjos, R M; Zamboni, C B; Cardoso, R; Muniz, M; Corona, A; Valladares, D L; Kovacs, L; Macario, K; Perea, D; Goso, C; Velasco, H

    2014-10-01

    Fossil bones are often the only materials available for chronological reconstruction of important archeological sites. However, since bone is an open system for uranium, it cannot be dated directly and therefore it is necessary to develop models for the U uptake. Hence, a radial diffusion-adsorption (RDA) model is described. Unlike the classic diffusion-adsorption (D-A) model, RDA uses a cylindrical geometry to describe the U uptake in fossil bones. The model was applied across a transverse section of a tibia of an extinct megamammal Macrauchenia patachonica from the La Paz Local Fauna, Montevideo State, Uruguay. Measurements of spatial distribution of Na, K, Ca, and Mg were also performed by neutron activation analysis (NAA). Gamma-ray spectrometric U-series dating was applied to determine the age of the bone sample. From U concentration profile, it was possible to observe the occurrence of a relatively slow and continuous uranium uptake under constant conditions that had not yet reached equilibrium, since the uranium distribution is a ∪-shaped closed-system. Predictions of the RDA model were obtained for a specific geochemical scenario, indicating that the effective diffusion coefficient D/R in this fossil bone is (2.4 ± 0.6)10(-12) cm(2)s(-1). Mean values of Na, K, Ca, and Mg contents along the radial line of the fossil tibia are consistent with the expected behavior for spatial distributions of these mineral elements across a modern bone section. This result indicates that the fossil tibia may have its mineral structure preserved. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Interaction of radon and smoking among Czech uranium miners using model of a threshold energy

    International Nuclear Information System (INIS)

    Boehm, R.; Holy, K.; Sedlak, A.

    2014-01-01

    Exposure to radon and smoking are among the most important factors influencing the risk of lung cancer. However, the joint effect of radon and smoking has not been sufficiently investigated so far. In this paper we will try to describe by means of a threshold energy model the mechanism of synergic effect of the aforementioned factors, and compare their influence on the risk of lung cancer. The model is based on the assumption that the inactivation of cells is caused by the excess of threshold specific energy z0 in the sensitive volume of the cell. Cigarette smoking causes, among others, an increase in the synthesis of the survivin protein that protects cells from apoptosis and thereby reduces their radiosensitivity. Survivin is therefore responsible for the increase of threshold energy z0, which in turn leads to the increase of lung cancer risk. A linear relationship between the threshold energy and the number of cigarettes smoked was assumed. The effect of smoking on radon exposure was evaluated for various groups of smokers that were defined by the degree of morphometric and geometric changes in the lungs induced by smoking and various degrees of chronic obstructive pulmonary disease. We simulate various scenarios of irradiation - short-term exposure, long-term exposure, as well as various smoking habits - smoker, ex-smoker. The calculated values can be, to an extent, compared to the epidemiological analysis geometric mixture models of Tomasek, who statistically evaluated epidemiological data about lung cancer occurrence among miners working in Jachymov and Pribram mines. From the results it follows that the correlation coefficient was particularly high. Although the approach outlined in this paper is only one of the many that strive to describe in detail the synergic effect of smoking and exposition, the used model can contribute to a more precise estimate of lung cancer risk in areas with various smoking habits. (authors)

  3. Complexation modeling of uranium and other actinides by organic compounds of natural or synthetic origin

    International Nuclear Information System (INIS)

    Bouby, M.

    1998-01-01

    The behaviour of nuclear wastes raises many questions, the answers of which require a precise knowledge of the physical, chemical and biological processes affecting the properties of the radio-elements present in the wastes. Three ways of research are approached. The results obtained give some elements of answer to these questions. The experimental methods that have been used are the neutron activation analysis, the UV-visible spectrophotometry, and the time-resolved laser spectro-fluorimetry. The analysis of the results has permitted to model part of the phenomena evidenced by using suitable ionic force correction models (Davies or MSA type) when chemical equilibria have been considered. The main results show: the bio-sorption capacities of Mycobacterium phlei microorganism with respect to UO 2 2+ and NpO 2+ cations such as: Q eq (UO 2 2+ ) = 60 and Q eq (NpO 2+ ) = 444 moles of cation per g of dry biomass; the retention capacities, in various leaching conditions, of this bacteria of the preliminarily adsorbed ions; the complexation properties of two siderophores with respect to UO 2 2+ , U 4+ and Th 4+ cations. One siderophore, Pyoverdine A, shows a selectiveness which is explained by the value of the thermodynamic equilibrium constant determined for each cation using the same model: K(UO 2 2+ ) 4+ ) 4+ ). The behaviour in highly acid environment (HCl and HClO 4 up to 12 M) of acylisoxazolone HPBI (1-phenyl-4-benzoyl-5-isoxazolone) and the value of its acidity thermodynamical constant (0.13 th 4 and CF 3 SO 3 H up to 12 M). It seems that a complexation between uranyl and the counter-ions present in the solution occurs. (J.S.)

  4. Formation-evolution model of uranium-productive basin and its recognition criteria

    International Nuclear Information System (INIS)

    Chen Zuyi; Li Ziying; Zhou Weixun; Guan Taiyang

    2004-11-01

    Based on geologic-tectonic setting and dynamic evolution of important U-productive basins both at home and abroad, authors distinguish six type of U-productive basins, and nominate each type by typical representative of this type, namely Chu-Sarysu and Syr-Darya type, Central Kyzylkum type, Zaural and West-Siberia type, Zabaikal type, Bohemia type, and South Texas type. The formation-evolution model of each type of U-productive basin has been established and recognition criteria have been proposed. Finially, the difference between each type U-productive basin is discussed and some assumption on prospecting for U-productive basins is proposed. (authors)

  5. Formation-evolution model of uranium-productive basin and its recognition criteria

    Energy Technology Data Exchange (ETDEWEB)

    Zuyi, Chen; Ziying, Li [Beijing Research Inst. of Uranium Geology, Beijing (China); Weixun, Zhou; Taiyang, Guan [East China Inst. of Technology, Fuzhou (China)

    2004-11-15

    Based on geologic-tectonic setting and dynamic evolution of important U-productive basins both at home and abroad, authors distinguish six type of U-productive basins, and nominate each type by typical representative of this type, namely Chu-Sarysu and Syr-Darya type, Central Kyzylkum type, Zaural and West-Siberia type, Zabaikal type, Bohemia type, and South Texas type. The formation-evolution model of each type of U-productive basin has been established and recognition criteria have been proposed. Finially, the difference between each type U-productive basin is discussed and some assumption on prospecting for U-productive basins is proposed. (authors)

  6. Natural uranium

    International Nuclear Information System (INIS)

    Ammerich, Marc; Frot, Patricia; Gambini, Denis-Jean; Gauron, Christine; Moureaux, Patrick; Herbelet, Gilbert; Lahaye, Thierry; Pihet, Pascal; Rannou, Alain

    2014-08-01

    This sheet belongs to a collection which relates to the use of radionuclides essentially in unsealed sources. Its goal is to gather on a single document the most relevant information as well as the best prevention practices to be implemented. These sheets are made for the persons in charge of radiation protection: users, radioprotection-skill persons, labor physicians. Each sheet treats of: 1 - the radio-physical and biological properties; 2 - the main uses; 3 - the dosimetric parameters; 4 - the measurement; 5 - the protection means; 6 - the areas delimitation and monitoring; 7 - the personnel classification, training and monitoring; 8 - the effluents and wastes; 9 - the authorization and declaration administrative procedures; 10 - the transport; and 11 - the right conduct to adopt in case of incident or accident. This sheet deals specifically with natural uranium

  7. An improved model of fission gas atom transport in irradiated uranium dioxide

    Science.gov (United States)

    Shea, J. H.

    2018-04-01

    The hitherto standard approach to predicting fission gas release has been a pure diffusion gas atom transport model based upon Fick's law. An additional mechanism has subsequently been identified from experimental data at high burnup and has been summarised in an empirical model that is considered to embody a so-called fuel matrix 'saturation' phenomenon whereby the fuel matrix has become saturated with fission gas so that the continued addition of extra fission gas atoms results in their expulsion from the fuel matrix into the fuel rod plenum. The present paper proposes a different approach by constructing an enhanced fission gas transport law consisting of two components: 1) Fick's law and 2) a so-called drift term. The new transport law can be shown to be effectively identical in its predictions to the 'saturation' approach and is more readily physically justifiable. The method introduces a generalisation of the standard diffusion equation which is dubbed the Drift Diffusion Equation. According to the magnitude of a dimensionless Péclet number, P, the new equation can vary from pure diffusion to pure drift, which latter represents a collective motion of the fission gas atoms through the fuel matrix at a translational velocity. Comparison is made between the saturation and enhanced transport approaches. Because of its dependence on P, the Drift Diffusion Equation is shown to be more effective at managing the transition from one type of limiting transport phenomenon to the other. Thus it can adapt appropriately according to the reactor operation.

  8. Surface complexation modeling of uranium (Vi) retained onto zirconium diphosphate in presence of organic acids

    International Nuclear Information System (INIS)

    Almazan T, M. G.; Garcia G, N.; Ordonez R, E.

    2010-10-01

    In the field of nuclear waste disposal, predictions regarding radionuclide migration through the geosphere, have to take account the effects of natural organic matter. This work presents an investigation of interaction mechanisms between U (Vi) and zirconium diphosphate (ZrP 2 O 7 ) in presence of organic acids (citric acid and oxalic acid). The retention reactions were previously examined using a batch equilibrium method. Previous results showed that U (Vi) retention was more efficient when citric acid or oxalic acid was present in solid surface at lower ph values. In order to determine the retention equilibria for both systems studied, a phosphorescence spectroscopy study was carried out. The experimental data were then fitted using the Constant Capacitance Model included in the FITEQL4.0 code. Previous results concerning surface characterization of ZrP 2 O 7 (surface sites density and surface acidity constants) were used to constraint the modeling. The best fit for U (Vi)/citric acid/ZrP 2 O 7 and U (Vi)/oxalic acid/ZrP 2 O 7 systems considered the formation of a ternary surface complex. (Author)

  9. 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

  10. 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

  11. 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)

  12. Modeling of uranium alloy response in plane impact and reverse ballistic experiments

    International Nuclear Information System (INIS)

    Herrmann, B.; Landau, A.; Shvarts, D.; Favorsky, V.; Zaretsky, E.

    2002-01-01

    The dynamic behavior of a solution heat-treated, water-quenched and aged U-0.75wt%Ti alloy was studied in planar (disk-on-disk) and reverse ballistic (disk-on-rod) impact experiments performed with a 25 mm light-gas gun. The impact velocity ranged from 100 to 500 m/sec. The impacted samples were softly recovered for further metallographic examination. The VISAR records of the sample free surface velocity, obtained in planar impact experiments, were simulated with 1-D hydrocode for calibrating the parameters of modified Steinberg-Cochran-Guinan (SCG) constitutive equation of the alloy. The same SCG equation was employed in 2-D AUTODYN simulation of the alloy response in the reverse ballistic experiments, with VISAR monitoring of the lateral sample surface velocity. Varying the parameters of the strain-dependent failure model allows relating the features of the recorded velocity profiles with the results of the examination of the damaged samples

  13. An analytical model for a low-level uranium detector for soil analysis

    International Nuclear Information System (INIS)

    Fortkamp, J.C.

    1994-01-01

    This thesis addresses the need for a field useable means of measuring the concentration of 238 U in soil. An analytical model was developed and refined based on a method conceived by David Holcomb. The method utilizes the high energy β of 234m Pa, a daughter in secular equilibrium with 238 U. A subtraction of the contribution of any other high energy β emitters present is done using a gamma coincidence system. The main component of the detector system defined was a 30cmx60cmx0.2cm plastic scintillating sheet. It was also shown that with proper calibration, the subtraction process will give accurate measurements of the 238 U concentration

  14. Fabrication of uranium-americium mixed oxide fuels: thermodynamical modeling and materials properties

    International Nuclear Information System (INIS)

    Prieur, D.

    2011-01-01

    Fuel irradiation in pressurized water reactors lead to the formation of fission products and minor actinides (Np, Am, Cm) which can be transmuted in fast neutrons reactors. In this context, the aim of this work was to study the fabrication conditions of the U 1-y Am y O 2+x fuels which exhibit particular thermodynamical properties requiring an accurate monitoring of the oxygen potential during the sintering step. For this reason, a thermodynamical model was developed to assess the optimum sintering conditions for these materials. From these calculations, U 1-y Am y O 2+x (y=0.10; 0.15; 0.20; 0.30) were sintered in two range of atmosphere. In hyper-stoichiometric conditions at low temperature, porous and multiphasic compounds are obtained whereas in reducing conditions at high temperature materials are dense and monophasic. XAFS analyses were performed in order to obtain additional experimental data for the thermodynamical modeling refinement. These characterizations also showed the reduction of Am(+IV) to Am(+III) and the partial oxidation of U(+IV) to U(+V) due to a charge compensation mechanism occurring during the sintering. Finally, taking into account the high - activity of Am, self-irradiation effects were studied for two types of microstructures and two Am contents (10 and 15%). For each composition, a lattice parameter increase was observed without structural change coupled with a macroscopic swelling of the pellet diameter up to 1.2% for the dense compounds and 0.6% for the tailored porosity materials. (author) [fr

  15. Complexation modelling of uranium and other actinides by organic compounds of natural or synthetic origin

    International Nuclear Information System (INIS)

    Bouby, M.

    1998-01-01

    The future of nuclear wastes raises a lot of questions. Their resolution require an accurate knowledge of the physical, chemical and biological processes which affect the properties of radioelements constituting the wastes. 3 research themes have been approached. The experimental methods used are: neutronic activation analysis, UV-visible spectrophotometry and time-resolved induced laser spectro-fluorimetry. A part of the phenomena has been modelled by ionic strength correction models (as Davies or MSA). The main results have revealed: 1)the bio-sorption capacities of the microorganism (Mycobacterium phlei) for UO 2 2+ and NpO 2+ (in conditions where the specific adsorption capacities Qe(UO 2 2+ )=60 and Qe(NpO 2+ )=444 moles cations/g dry biomass 2)the retention capacities, in various leaching conditions, by this bacteria of the ions initially adsorbed 3)the complexation properties of 2 siderophores for the cations UO 2 2+ , U 4+ and Th 4+ . The thermodynamical equilibrium constants were determined for one of the siderophore: the pyoverdine A; they were such that KUO 2 2+ ≤KU 4+ ≤KTh 4+ 4)in very acidic media (HCl and HClO 4 until 12 M), the behaviour of the acylisoxazolone HPBI (1-phenyl-4-benzoyl-5-isoxazolone) and the value of its acidity thermodynamical constant is such that 0.13≤KATh≤0.32 at 25 degrees Celsius 5)the variations of the fluorescence properties of the uranyl cation in terms of the acidity of the concentrated media (HClO 4 and CF 3 SO 3 H) in which they are in solution; it seems that a complexation between the uranyl ion and the counter-ions present in solution occur. (O.M.)

  16. 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

  17. Comparison of the U-233 dog data of Stevens et al. with uranium retention functions in ICRP Publication 30 and a 3-compartment mammillary model for uranium

    International Nuclear Information System (INIS)

    Bernard, S.R.

    1983-01-01

    Stevens measured the distribution, retention, and excretion of U-233 in seven beagles each given a single injection of U-233 citrate [2.8 μCi/kg U-233 (VI) (approx.3 mg/dog)]. These data, when plotted together with results obtained with the ICRP (Pub. 30) retention functions for purposes of comparison, are seen to differ only slightly from the ICRP-30 model. The number of transformations in the body, over a fifty-year period agree within a factor of 2. A three-compartment mammillary model has been parameterized from the data of Stevens by the method of Bernard. Retention in tissues of the body is represented by a linear combination of three compartments. The data plots for the dogs and ICRP-30 model will be presented and discussed together with the three compartment mammillary model for U-233 retention, distribution, and excretion. 3 figs., 2 tabs

  18. 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)

  19. 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)

  20. 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

  1. 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

  2. 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

  3. Computer modelling of the chemical speciation of caesium, uranium(VI) and neptunium(V) in human duodenal fluids under fasting conditions

    International Nuclear Information System (INIS)

    Jones, P.W.; Taylor, D.M.; Webb, L.M.; Williams, D.R.

    2002-01-01

    A model simulating the human duodenal contents under physiologically realistic, fasting conditions was developed using the joint expert speciation system (JESS) computer program and database and used to investigate the chemical speciation of caesium, uranium(VI) and neptunium(V). Over the pH range 5.0-9.0, and the concentration range 5x10 -15 -5x10 -5 mol dm -3 , caesium was predicted to occur predominantly as the absorbable free monovalent cation Cs + (∼95%) with species such as CsHPO 4 - and CsCl representing the remainder. The presence or absence of sulphate at 2.1x10 -3 mol dm -3 did not influence the predicted speciation. Uranium was predicted to be present entirely as a soluble, highly charged species, both in the absence and in the presence of sulphate. Between pH 5.0 and ∼6.5 the UO 2 H 2 (PO 4 ) 2 2- predominated, above this pH carbonate species, either UO 2 (CO 3 ) 4 6- or, possibly, UO 2 (CO 3 ) 5 8- . At pH 8.0, and in the presence of sulphate, neptunium(V) was predicted to exist solely as the tetrasulphate species, whilst in the absence of sulphate, an array of negatively charged soluble carbonate species predominated. Studies over the pH range 5.0-9.0 predicted the formation of a spectrum of negatively charged carbonate and phosphate species, ∼40% of the total neptunium was predicted to be present as the electrically net-neutral species NpO 2 HCO 3 at pH6.0, ∼20% at pH 7.0, ∼10% at pH 7.5 and ∼1% at pH 8.0. The observed speciation patterns of uranium and neptunium did not change over the concentration range 5x10 -15 -5x10 -5 mol dm -3 and no solid species were predicted to occur under the conditions simulated. Whether the predicted electrically net-neutral neptunium species or the uranium pentacarbonate species do actually occur under true physiological conditions remains to be established. The observed speciation patterns for caesium and uranium are consistent with the observed absorption of these elements by humans; however, the

  4. Conceptual model: possible changes of the seawater uranium isotopic composition through time

    Energy Technology Data Exchange (ETDEWEB)

    Nowitzki, Hannah; Frank, Norbert; Fohlmeister, Jens [Universitaet Heidelberg (Germany)

    2015-07-01

    U behaves in seawater like a conservative element. More than 99% of the oceanic U content is {sup 238}U, whereas {sup 234}U is only present in trace amounts. As the residence time of U is significantly longer than the mixing time of the ocean, the ocean is well mixed with respect to U and its isotopic composition (Dunk 2002). Moreover, living corals incorporate U without isotopic fractionation. Therefore, the past seawater isotopic evolution of ({sup 234}U/{sup 238}U) can be accessed via U/Th age-dating of corals and the subsequent calculation of the initial ({sup 234}U/{sup 238}U) value. The isotopic ({sup 234}U/{sup 238}U) composition of seawater during the last 360 ka scatters around the modern seawater value (δ{sup 234}U ∼ (145±15) %, Henderson 2002). As these variations in the δ{sup 234}U value are rather small, a 'constant seawater isotopic composition hypothesis' is often used to validate U/Th ages of fossil corals. However, some authors find that the variability of the isotopic composition exceeds the expected range and suggest that it provides valuable information on variations in continental weathering and global run-off fluctuations or sea-level changes. This work will attempt to compare literature data of the seawater U isotopic composition to the results of a conceptual box-model of the oceanic U budget.

  5. Simmer model of a low-enriched uranium non-power reactor

    International Nuclear Information System (INIS)

    Wilhelm, Dirk; Biaut, Guillaume; Tobita, Yoshiharu

    2006-01-01

    IRSN has started to use the coupled neutronics - fluid dynamics code SIMMER to study core-disruptive accident induced by insertions of large reactivities sufficient to very short period power excursions in fuel plate-type and water-moderated experimental research reactors. Until now, French safety analysis retain thermal energy released and mechanical yields, deduced from analysis of destructive test programs SPERT-I and BORAX-I to demonstrate the behavior of such reactors and design their structures and containment. The present research program models the design basis accident of a low enriched fuel currently used in experimental research reactors contrary to SPERT-I or BORAX-I. The objective is to analyze the effects of counter reactivities and how these would limit the generated thermal energy in the fuel. This part demands a close coupling to the fluid dynamics analysis. The consequences of the nuclear power excursion, the changes of state of the fuel and the coolant, and ultimately the mechanical energy released are calculated by SIMMER. For large step-wise reactivity introductions, the Doppler effect limits the power excursion before energy is released high enough to melt a large part of the fuel. Moreover, it has been shown that imposing an external reactivity as a step-wise or time dependant reactivity introduction yields results quite different from those of the physical movement of control rods. (author)

  6. SIMMER model of a low-enriched uranium non-power reactor

    International Nuclear Information System (INIS)

    Wilhelm, Dirk; Biaut, Guillaume; Tobita, Yoshiharu

    2008-01-01

    IRSN has started using the coupled neutronics-fluid dynamics code SIMMER [] to study core-disruptive accidents induced by insertions of large reactivities to produce very short period power excursions in fuel plate-type and water-moderated experimental research reactors. Until now, French safety analyses retain a bounding thermal energy released and mechanical yields, deduced from analysis of destructive in-pile test programs, to study the behavior of such reactors and design their structures and containment. Contrary to this approach, the present research program aims at modeling the design basis accident of research reactors with a low-enriched fuel using a CFD code. The objective is to analyze the effects of reactivity feedbacks and how they would limit the generated thermal energy released in the fuel. These aspects require a close coupling of the neutronics to the fluid dynamics analysis. The consequences of the nuclear power excursion, the changes of state of the fuel and the coolant, and ultimately the mechanical energy released are calculated by SIMMER. For large step-wise reactivity introductions, the Doppler effect and, at a lower extent, the fuel element thermal dilatation, which generates locally a decrease of the moderator to fuel ratio, limit the power excursion before the energy released is high enough to melt a large part of the fuel. Moreover, it has been shown that imposing an external reactivity as a step-wise or time-dependent reactivity introduction yields results quite different from those of the physical movement of control rods

  7. Alligator Rivers Analogue project. Geochemical modelling of secondary uranium ore formation. Final Report - Volume 11

    International Nuclear Information System (INIS)

    Sverjensky, D.; Bennett, D.G.; Read, D.

    1992-01-01

    The purpose of the present study was to establish how the uranyl phosphate zone at the Koongarra site was formed. The overall approach taken in the present study employed theoretical chemical mass transfer calculations and models that permit investigation and reconstruction of the kinds of waters that could produce the uranyl phosphate zone. These calculations have used the geological and mineralogical data for the Koongarra weathered zone (Volumes 2, 8, and 9 of this series), to constrain the initial compositions and reactions undergone by groundwater during the formation of the uranyl phosphate zone. In carrying out these calculations the present-day analyses of Koongarra waters are used only as a guide to the possible initial composition of the fluids associated with the formation of the phosphate zone. Aqueous speciation, saturation state and chemical mass transfer calculations were carried out using the computer programs EQ3NR and EQ6 (Wolery, 1983; Wolery et al., 1984) and a thermodynamic database generated at The Johns Hopkins University over the last eight years which is tabulated in the Appendix 1 to Volume 12 of this series. Despite uncertainties in the thermodynamic characterisation of species, all the above calculations suggest that the uranyl phosphate zone at Koongarra has not formed from present-day groundwaters (Volume 12 of this series). The present-day groundwaters in the weathered zone (eg. at 13 m depth) appear to be undersaturated with respect to saleeite. Furthermore, as present-day groundwaters descend below the water table they rapidly lose their atmospheric oxygen imprint, as is typical of most groundwaters, and become even more reducing in character. Under these circumstances, the groundwaters become more undersaturated with respect to saleeite than the shallow groundwaters. Because much of the phosphate zone is currently below the water table, under saturated zone conditions, it is suggested in the present study that the uranyl phosphate

  8. Alligator Rivers Analogue project. Geochemical modelling of secondary uranium ore formation. Final Report - Volume 11

    Energy Technology Data Exchange (ETDEWEB)

    Sverjensky, D [The John Hopkins Univ, Dept of Earth and Planetary Sciences, Baltimore (United States); Bennett, D G; Read, D [W.S. Atkins Science and Technology, Epsom Surrey, (United Kingdom)

    1993-12-31

    The purpose of the present study was to establish how the uranyl phosphate zone at the Koongarra site was formed. The overall approach taken in the present study employed theoretical chemical mass transfer calculations and models that permit investigation and reconstruction of the kinds of waters that could produce the uranyl phosphate zone. These calculations have used the geological and mineralogical data for the Koongarra weathered zone (Volumes 2, 8, and 9 of this series), to constrain the initial compositions and reactions undergone by groundwater during the formation of the uranyl phosphate zone. In carrying out these calculations the present-day analyses of Koongarra waters are used only as a guide to the possible initial composition of the fluids associated with the formation of the phosphate zone. Aqueous speciation, saturation state and chemical mass transfer calculations were carried out using the computer programs EQ3NR and EQ6 (Wolery, 1983; Wolery et al., 1984) and a thermodynamic database generated at The Johns Hopkins University over the last eight years which is tabulated in the Appendix 1 to Volume 12 of this series. Despite uncertainties in the thermodynamic characterisation of species, all the above calculations suggest that the uranyl phosphate zone at Koongarra has not formed from present-day groundwaters (Volume 12 of this series). The present-day groundwaters in the weathered zone (eg. at 13 m depth) appear to be undersaturated with respect to saleeite. Furthermore, as present-day groundwaters descend below the water table they rapidly lose their atmospheric oxygen imprint, as is typical of most groundwaters, and become even more reducing in character. Under these circumstances, the groundwaters become more undersaturated with respect to saleeite than the shallow groundwaters. Because much of the phosphate zone is currently below the water table, under saturated zone conditions, it is suggested in the present study that the uranyl phosphate

  9. Alligator Rivers Analogue project. Geochemical modelling of secondary uranium ore formation. Final Report - Volume 11

    Energy Technology Data Exchange (ETDEWEB)

    Sverjensky, D. [The John Hopkins Univ, Dept of Earth and Planetary Sciences, Baltimore (United States); Bennett, D.G.; Read, D. [W.S. Atkins Science and Technology, Epsom Surrey, (United Kingdom)

    1992-12-31

    The purpose of the present study was to establish how the uranyl phosphate zone at the Koongarra site was formed. The overall approach taken in the present study employed theoretical chemical mass transfer calculations and models that permit investigation and reconstruction of the kinds of waters that could produce the uranyl phosphate zone. These calculations have used the geological and mineralogical data for the Koongarra weathered zone (Volumes 2, 8, and 9 of this series), to constrain the initial compositions and reactions undergone by groundwater during the formation of the uranyl phosphate zone. In carrying out these calculations the present-day analyses of Koongarra waters are used only as a guide to the possible initial composition of the fluids associated with the formation of the phosphate zone. Aqueous speciation, saturation state and chemical mass transfer calculations were carried out using the computer programs EQ3NR and EQ6 (Wolery, 1983; Wolery et al., 1984) and a thermodynamic database generated at The Johns Hopkins University over the last eight years which is tabulated in the Appendix 1 to Volume 12 of this series. Despite uncertainties in the thermodynamic characterisation of species, all the above calculations suggest that the uranyl phosphate zone at Koongarra has not formed from present-day groundwaters (Volume 12 of this series). The present-day groundwaters in the weathered zone (eg. at 13 m depth) appear to be undersaturated with respect to saleeite. Furthermore, as present-day groundwaters descend below the water table they rapidly lose their atmospheric oxygen imprint, as is typical of most groundwaters, and become even more reducing in character. Under these circumstances, the groundwaters become more undersaturated with respect to saleeite than the shallow groundwaters. Because much of the phosphate zone is currently below the water table, under saturated zone conditions, it is suggested in the present study that the uranyl phosphate

  10. Uranium: a basic evaluation

    International Nuclear Information System (INIS)

    Crull, A.W.

    1978-01-01

    All energy sources and technologies, including uranium and the nuclear industry, are needed to provide power. Public misunderstanding of the nature of uranium and how it works as a fuel may jeopardize nuclear energy as a major option. Basic chemical facts about uranium ore and uranium fuel technology are presented. Some of the major policy decisions that must be made include the enrichment, stockpiling, and pricing of uranium. Investigations and lawsuits pertaining to uranium markets are reviewed, and the point is made that oil companies will probably have to divest their non-oil energy activities. Recommendations for nuclear policies that have been made by the General Accounting Office are discussed briefly

  11. 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

  12. Uranium: one utility's outlook

    International Nuclear Information System (INIS)

    Gass, C.B.

    1983-01-01

    The perspective of the Arizona Public Service Company (APS) on the uncertainty of uranium as a fuel supply is discussed. After summarizing the history of nuclear power and the uranium industries, a projection is made for the future uranium market. An uncrtain uranium market is attributed to various determining factors that include international politics, production costs, non-commercial government regulation, production-company stability, and questionable levels of uranium sales. APS offers its solutions regarding type of contract, choice of uranium producers, pricing mechanisms, and aids to the industry as a whole. 5 references, 10 figures, 1 table

  13. Methods for analyzing occupational cohort data with application to lung cancer in US uranium miners: Techniques for fitting and checking exposure-time-response models

    International Nuclear Information System (INIS)

    Halpern, J.; Whittemore, A.S.

    1987-01-01

    Two methods were used to examine how lung cancer death rates vary with cumulative exposures to radiation and tobacco among uranium miners. The two methods produced similar results when death rate ratios were taken to be the product of radiation and tobacco effects. The estimates were discrepant when death rate ratios were taken to be the sum of radiation and tobacco effects. Both methods indicated better fit for the multiplicative model. It may be that cumulative exposures are inappropriate measures of the effects of radiation and tobacco on lung cancer death rates, as well as for other pollutants where the assumption of cumulative dose is the basis for risk assessments

  14. 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)

  15. 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.

  16. Towards a Predictive Thermodynamic Model of Oxidation States of Uranium Incorporated in Fe (hydr) oxides

    Energy Technology Data Exchange (ETDEWEB)

    Bagus, Paul S. [Univ. of North Texas, Denton, TX (United States)

    2013-01-01

    -Level Excited States: Consequences For X-Ray Absorption Spectroscopy”, J. Elec. Spectros. and Related Phenom., 200, 174 (2015) describes our first application of these methods. As well as applications to problems and materials of direct interest for our PNNL colleagues, we have pursued applications of fundamental theoretical significance for the analysis and interpretation of XPS and XAS spectra. These studies are important for the development of the fields of core-level spectroscopies as well as to advance our capabilities for applications of interest to our PNNL colleagues. An excellent example is our study of the surface core-level shifts, SCLS, for the surface and bulk atoms of an oxide that provides a new approach to understanding how the surface electronic of oxides differs from that in the bulk of the material. This work has the potential to lead to a new key to understanding the reactivity of oxide surfaces. Our theoretical studies use cluster models with finite numbers of atoms to describe the properties of condensed phases and crystals. This approach has allowed us to focus on the local atomistic, chemical interactions. For these clusters, we obtain orbitals and spinors through the solution of the Hartree-Fock, HF, and the fully relativistic Dirac HF equations. These orbitals are used to form configuration mixing wavefunctions which treat the many-body effects responsible for the open shell angular momentum coupling and for the satellites of the core-level spectra. Our efforts have been in two complementary directions. As well as the applications described above, we have placed major emphasis on the enhancement and extension of our theoretical and computational capabilities so that we can treat complex systems with a greater range of many-body effects. Noteworthy accomplishments in terms of method development and enhancement have included: (1) An improvement in our treatment of the large matrices that must be handled when many-body effects are treated. (2

  17. 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.

  18. Uranium production

    International Nuclear Information System (INIS)

    Jones, J.Q.

    1981-01-01

    The domestic uranium industry is in a state of stagflation. Costs continue to rise while the market for the product remains stagnant. During the last 12 months, curtailments and closures of mines and mills have eliminated over 5000 jobs in the industry, plus many more in those industries that furnish supplies and services. By January 1982, operations at four mills and the mines that furnish them ore will have been terminated. Other closures may follow, depending on cost trends, duration of current contracts, the degree to which mills have been amortized, the feasibility of placing mines on standby, the grade of the ore, and many other factors. Open-pit mines can be placed on standby without much difficulty, other than the possible cost of restoration before all the ore has been removed. There are a few small, dry, underground mines that could be mothballed; however, the major underground producers are wet sandstone mines that in most cases could not be reopened after a prolonged shutdown; mills can be mothballed for several years. Figure 8 shows the location of all the production centers in operation, as well as those that have operated or are on standby. Table 1 lists the same production centers plus those that have been deferred, showing nominal capacity of conventional mills in tons of ore per calendar day, and the industry production rate for those mills as of October 1, 1981

  19. Granite metallogenic specialization study based on RS information model-A case of hydrothermal uranium and tungsten deposits in Nanling region

    International Nuclear Information System (INIS)

    Huang Hongye; Qin Qiming

    2009-01-01

    According to the granite hydrothermal metallogenic principle, metallogenic specialization information model for uranium producing and tungsten producing granites in Nanling region is built up and the group factor system of granite metallogenic specialization is initially proposed by using RS information model. On the basis of the above aspects, the geographical index and coefficients of information model of granite metallogenic specialization are respectively analyzed, metallogenic specialization discrimination criterion is built up. After the non-discriminatory massif is forecasted, the results are basically accordant with geological fact, at the same time they are used in the geological metallogenic research, which indicates that metallogenic specialization information model is objective and operative, realizes quantitative appraisal on metallogenic specialization and provides a scientific basis for further discriminating the ore-forming massif. (authors)

  20. INTRAVAL phase 2, test case 8. Alligator Rivers Natural Analogue - Modelling of uranium transport in the weathered zone at Koongarra (Australia). Progress report

    NARCIS (Netherlands)

    van der Weerd H; Hassanizadeh SM; Richardson-van der Poel MA; LBG

    1993-01-01

    A study of uranium transport in the Koongarra site of Alligator Rivers Uranium deposit (Australia) is carried out. The analysis of the solid phase uranium concentration measured at various depths provides a useful picture of the dispersion process. Results of this analysis seem to support the

  1. Adsorption of uranium on halloysite

    International Nuclear Information System (INIS)

    Kilislioglu, A.; Bilgin, B.

    2002-01-01

    Adsorption of uranium (U(VI)) from aqueous solutions on halloysite type clay was studied as a function of amount of adsorbent, initial concentration and pH. The values of adsorption data were fitted to Freundlich, Langmuir and Dubinin-Radushkevich (D-R) adsorption isotherms. The mean energy of adsorption was calculated as 5.91 kJ/mol from D-R adsorption isotherm. Lagergren and Bangham equation has been used for dynamic modelling of process and the rate constants of adsorption of uranium on halloysite type clay were calculated at 293, 313 and 333 K. In order to explain the mechanism of adsorption reaction, the rate constants were calculated at high and low uranium concentrations. Adsorption reaction was studied at 293, 303, 313, 323 and 333 K for halloysite type clay and also thermodynamic constants have been calculated. The results show that the adsorption reaction was endothermic and more spontaneous at high temperature. (orig.)

  2. Adsorption of uranium on halloysite

    Energy Technology Data Exchange (ETDEWEB)

    Kilislioglu, A.; Bilgin, B. [Istanbul Univ. (Turkey). Faculty of Engineering

    2002-07-01

    Adsorption of uranium (U(VI)) from aqueous solutions on halloysite type clay was studied as a function of amount of adsorbent, initial concentration and pH. The values of adsorption data were fitted to Freundlich, Langmuir and Dubinin-Radushkevich (D-R) adsorption isotherms. The mean energy of adsorption was calculated as 5.91 kJ/mol from D-R adsorption isotherm. Lagergren and Bangham equation has been used for dynamic modelling of process and the rate constants of adsorption of uranium on halloysite type clay were calculated at 293, 313 and 333 K. In order to explain the mechanism of adsorption reaction, the rate constants were calculated at high and low uranium concentrations. Adsorption reaction was studied at 293, 303, 313, 323 and 333 K for halloysite type clay and also thermodynamic constants have been calculated. The results show that the adsorption reaction was endothermic and more spontaneous at high temperature. (orig.)

  3. Uranium mining in Australia

    International Nuclear Information System (INIS)

    Anon.

    1980-01-01

    Known uranium deposits and the companies involved in uranium mining and exploration in Australia are listed. The status of the development of the deposits is outlined and reasons for delays to mining are given

  4. Uranium Processing Facility

    Data.gov (United States)

    Federal Laboratory Consortium — An integral part of Y‑12's transformation efforts and a key component of the National Nuclear Security Administration's Uranium Center of Excellence, the Uranium...

  5. Uranium in Niger

    International Nuclear Information System (INIS)

    Gabelmann, E.

    1978-03-01

    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 [fr

  6. Price of military uranium

    International Nuclear Information System (INIS)

    Klimenko, A.V.

    1998-01-01

    The theoretical results about optimum strategy of use of military uranium confirmed by systems approach accounts are received. The numerical value of the system approach price of the highly enriched military uranium also is given

  7. Uranium market and resources

    International Nuclear Information System (INIS)

    Capus, G.; Arnold, Th.

    2004-01-01

    The controversy about the extend of the uranium resources worldwide is still important, this article sheds some light on this topic. Every 2 years IAEA and NEA (nuclear energy agency) edit an inventory of uranium resources as reported by contributing countries. It appears that about 4.6 millions tons of uranium are available at a recovery cost less than 130 dollars per kg of uranium and a total of 14 millions tons of uranium can be assessed when including all existing or supposed resources. In fact there is enough uranium to sustain a moderate growth of the park of nuclear reactors during next decades and it is highly likely that the volume of uranium resources can allow a more aggressive development of nuclear energy. It is recalled that a broad use of the validated breeder technology can stretch the durability of uranium resources by a factor 50. (A.C.)

  8. Uranium from phosphate ores

    International Nuclear Information System (INIS)

    Hurst, F.J.

    1983-01-01

    The following topics are described briefly: the way phosphate fertilizers are made; how uranium is recovered in the phosphate industry; and how to detect covert uranium recovery operations in a phsophate plant

  9. Industrial realities: Uranium

    International Nuclear Information System (INIS)

    Thiron, H.

    1990-01-01

    In this special issue are examined ores and metals in France and in the world for 1988. The chapter on uranium gives statistical data on the uranium market: Demand, production, prices and reserves [fr

  10. Brazilian uranium deposits

    International Nuclear Information System (INIS)

    Santos, L.C.S. dos.

    1985-01-01

    Estimatives of uranium reserves carried out in Figueira, Itataia, Lagoa Real and Espinharas, in Brazil are presented. The samples testing allowed to know geological structures, and the characteristics of uranium mineralization. (M.C.F.) [pt

  11. Uranium mining in Australia

    International Nuclear Information System (INIS)

    Anon.

    1984-01-01

    The mining of uranium in Australia is criticised in relation to it's environmental impact, economics and effects on mine workers and Aborigines. A brief report is given on each of the operating and proposed uranium mines in Australia

  12. Application of the HGSYSTEM/UF6 model to simulate atmospheric dispersion of UF6 releases from uranium enrichment plants

    International Nuclear Information System (INIS)

    Goode, W.D. Jr.; Bloom, S.G.; Keith, K.D. Jr.

    1995-01-01

    Uranium hexafluoride is a dense, reactive gas used in Gaseous Diffusion Plants (GDPs) to make uranium enriched in the 235 U isotope. Large quantities of UF 6 exist at the GDPs in the form of in-process gas and as a solid in storage cylinders; smaller amounts exist as hot liquid during transfer operations. If liquid UF 6 is released to the environment, it immediately flashes to a solid and a dense gas that reacts rapidly with water vapor in the air to form solid particles of uranyl fluoride and hydrogen fluoride gas. Preliminary analyses were done on various accidental release scenarios to determine which scenarios must be considered in the safety analyses for the GDPS. These scenarios included gas releases due to failure of process equipment and liquid/gas releases resulting from a breach of transfer piping from a cylinder. A major goal of the calculations was to estimate the response time for mitigating actions in order to limit potential off-site consequences of these postulated releases. The HGSYSTEM/UF 6 code was used to assess the consequences of these release scenarios. Inputs were developed from release calculations which included two-phase, choked flow followed by expansion to atmospheric pressure. Adjustments were made to account for variable release rates and multiple release points. Superpositioning of outputs and adjustments for exposure time were required to evaluate consequences based on health effects due to exposures to uranium and HF at a specific location

  13. 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

  14. Simplified modeling photo-ionisation of uranium in Silva project; Modelisation simplifiee de la photo-ionisation de l'uranium dans le procede Silva

    Energy Technology Data Exchange (ETDEWEB)

    Bodin, B; Pourre-Brichot, P; Valadier, L [CEA Saclay, Dept. des Procedes d' Enrichissement (DCC/DPE/SPTE), 91 - Gif-sur-Yvette (France)

    2000-07-01

    SILVA is a process which targets {sup 235}U by photo-ionization. It is therefore important to compute the proportion of ionized atoms depending on the properties of the lasers. The interaction between atoms and lasers occurs via the link between the Maxwell and Schroedinger equations. This kind of approach is only feasible for a few simple cases: e.g. wave plane or simple laser profiling. Introducing the characteristics of SILVA, computation time increases substantially (several hundred days per kilogram of vapor). To circumvent this problem, we wrote a program (Jackpot) that treats photo-ionization by a simplified model: kinetics equations. However, various optical components were introduced with absorption factor by wavelength, to account for the effects of optics systems on the trajectory. Instead of seeking the complex wavefunction solutions of the Maxwell-Schroedinger equations, we solve a system where the unknown values are a set of populations. The size of the set depends only on the number of hold points in the process. Recent work shows that we can converge towards the same results as the Maxwell-Schroedinger system if we can fit the cross-sections of the kinetic system correctly. As to the optical aspect, Jackpot can handle diffraction. In this case, it solves the propagation equation of an electric field by a double Fourier transform method. For interactions with mirrors, the new direction of a ray is calculated with Descartes law, applying a numerical phase mask to the electric field. We account for diaphragmation mechanisms as well as the absorption law for each mirror, by a real factor by wavelength. Jackpot is simple to use and can be used to predict experimental results. Jackpot is now a library calling by a script written in Python. Changes are being made for a closer approach to reality (real laser, new photo-ionization model)

  15. Uranium mining in Australia

    International Nuclear Information System (INIS)

    Mackay, G.A.

    1978-01-01

    Western world requirements for uranium based on increasing energy consumption and a changing energy mix, will warrant the development of Australia's resources. By 1985 Australian mines could be producing 9500 tonnes of uranium oxide yearly and by 1995 the export value from uranium could reach that from wool. In terms of benefit to the community the economic rewards are considerable but, in terms of providing energy to the world, Australias uranium is vital

  16. Radiation damage of uranium

    International Nuclear Information System (INIS)

    Lazarevic, Dj.

    1966-11-01

    Study of radiation damage covered the following: Kinetics of electric resistance of uranium and uranium alloy with 1% of molybdenum dependent on the second phase and burnup rate; Study of gas precipitation and diffusion of bubbles by transmission electron microscopy; Numerical analysis of the influence of defects distribution and concentration on the rare gas precipitation in uranium; study of thermal sedimentation of uranium alloy with molybdenum; diffusion of rare gas in metal by gas chromatography method

  17. Bicarbonate leaching of uranium

    International Nuclear Information System (INIS)

    Mason, C.

    1998-01-01

    The alkaline leach process for extracting uranium from uranium ores is reviewed. This process is dependent on the chemistry of uranium and so is independent on the type of mining system (conventional, heap or in-situ) used. Particular reference is made to the geochemical conditions at Crownpoint. Some supporting data from studies using alkaline leach for remediation of uranium-contaminated sites is presented

  18. Bicarbonate leaching of uranium

    Energy Technology Data Exchange (ETDEWEB)

    Mason, C.

    1998-12-31

    The alkaline leach process for extracting uranium from uranium ores is reviewed. This process is dependent on the chemistry of uranium and so is independent on the type of mining system (conventional, heap or in-situ) used. Particular reference is made to the geochemical conditions at Crownpoint. Some supporting data from studies using alkaline leach for remediation of uranium-contaminated sites is presented.

  19. Uranium in fossil bones

    International Nuclear Information System (INIS)

    Koul, S.L.

    1978-01-01

    An attempt has been made to determine the uranium content and thus the age of certain fossil bones Haritalyangarh (Himachal Pradesh), India. The results indicate that bones rich in apatite are also rich in uranium, and that the radioactivity is due to radionuclides in the uranium series. The larger animals apparently have a higher concentration of uranium than the small. The dating of a fossil jaw (elephant) places it in the Pleistocene. (Auth.)

  20. Uranium evaluation and mining techniques

    International Nuclear Information System (INIS)

    1980-01-01

    accurate, comprehensive, and understandable appraisal of the world's potential uranium resources, and the ability to discover, develop and produce these resources within an acceptable time frame are absolutely essential to making meaningful decisions in relation to the future supply of nuclear fuel. Therefore, the methods used to appraise undiscovered uranium resources were examined and compared in the light of the needs of the world nuclear power industry as a whole. Notable among these methods is one based on interactive genetic models. It is currently being developed to reduce the amount of subjectivity inherent in most of the currently used appraisal techniques The goal is to use more geologic data and depend less on the intuition and experience of the estimator. The more esoteric statistical techniques based on past production rates, prices, rates of increase or decrease in reported reserves or resources, etc., while of unknown or unproved value, were not discussed at the symposium. The symposium provided a forum for discussion of closely related subjects as well. One of the major problems in reporting internationally in uranium resources is classification of the resources into various categories and defining those categories. Conceptually, among earth scientists, there is general agreement, but defining these concepts is a difficult task. At least three organizations have undertaken to develop classifications and definitions to satisfy the needs of international reporting. Two of these were described at the symposium. (The third has been used by the joint NEA/IAEA Working Party on Uranium Resources but was not described.) The techniques of winning uranium from its several sources include, besides mining by conventional open pit or underground methods, in situ leaching of low-grade ores in special environments, and from ores left in mines In addition, virtually all marine phosphates contain some uranium that can be recovered as a by-product in the manufacture of

  1. 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

  2. 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)

  3. Mechanistically-Based Field-Scale Models of Uranium Biogeochemistry from Upscaling Pore-Scale Experiments and Models

    International Nuclear Information System (INIS)

    Tim Scheibe; Alexandre Tartakovsky; Brian Wood; Joe Seymour

    2007-01-01

    Effective environmental management of DOE sites requires reliable prediction of reactive transport phenomena. A central issue in prediction of subsurface reactive transport is the impact of multiscale physical, chemical, and biological heterogeneity. Heterogeneity manifests itself through incomplete mixing of reactants at scales below those at which concentrations are explicitly defined (i.e., the numerical grid scale). This results in a mismatch between simulated reaction processes (formulated in terms of average concentrations) and actual processes (controlled by local concentrations). At the field scale, this results in apparent scale-dependence of model parameters and inability to utilize laboratory parameters in field models. Accordingly, most field modeling efforts are restricted to empirical estimation of model parameters by fitting to field observations, which renders extrapolation of model predictions beyond fitted conditions unreliable. The objective of this project is to develop a theoretical and computational framework for (1) connecting models of coupled reactive transport from pore-scale processes to field-scale bioremediation through a hierarchy of models that maintain crucial information from the smaller scales at the larger scales; and (2) quantifying the uncertainty that is introduced by both the upscaling process and uncertainty in physical parameters. One of the challenges of addressing scale-dependent effects of coupled processes in heterogeneous porous media is the problem-specificity of solutions. Much effort has been aimed at developing generalized scaling laws or theories, but these require restrictive assumptions that render them ineffective in many real problems. We propose instead an approach that applies physical and numerical experiments at small scales (specifically the pore scale) to a selected model system in order to identify the scaling approach appropriate to that type of problem. Although the results of such studies will

  4. Mechanistically-Based Field-Scale Models of Uranium Biogeochemistry from Upscaling Pore-Scale Experiments and Models

    Energy Technology Data Exchange (ETDEWEB)

    Tim Scheibe; Alexandre Tartakovsky; Brian Wood; Joe Seymour

    2007-04-19

    Effective environmental management of DOE sites requires reliable prediction of reactive transport phenomena. A central issue in prediction of subsurface reactive transport is the impact of multiscale physical, chemical, and biological heterogeneity. Heterogeneity manifests itself through incomplete mixing of reactants at scales below those at which concentrations are explicitly defined (i.e., the numerical grid scale). This results in a mismatch between simulated reaction processes (formulated in terms of average concentrations) and actual processes (controlled by local concentrations). At the field scale, this results in apparent scale-dependence of model parameters and inability to utilize laboratory parameters in field models. Accordingly, most field modeling efforts are restricted to empirical estimation of model parameters by fitting to field observations, which renders extrapolation of model predictions beyond fitted conditions unreliable. The objective of this project is to develop a theoretical and computational framework for (1) connecting models of coupled reactive transport from pore-scale processes to field-scale bioremediation through a hierarchy of models that maintain crucial information from the smaller scales at the larger scales; and (2) quantifying the uncertainty that is introduced by both the upscaling process and uncertainty in physical parameters. One of the challenges of addressing scale-dependent effects of coupled processes in heterogeneous porous media is the problem-specificity of solutions. Much effort has been aimed at developing generalized scaling laws or theories, but these require restrictive assumptions that render them ineffective in many real problems. We propose instead an approach that applies physical and numerical experiments at small scales (specifically the pore scale) to a selected model system in order to identify the scaling approach appropriate to that type of problem. Although the results of such studies will

  5. Characteristics of gravity and magnetic field and their relationship with uranium mineralization in northern Guangxi area

    International Nuclear Information System (INIS)

    Shu Xiaojing; Yin Zhongfan; Hao Yuhua; guan Nansheng; Li Xuexun

    1993-08-01

    The characteristics of gravity and magnetic field, deep-seated structures and their relationship with uranium mineralization in Northern Guangxi are investigated. Especially, based on geophysical investigation, the distinguishing features of uranium ore-forming are discussed, involved with the uranium source body, the heating force and mechanical force of granite magma acted on uranium mineralization, the deep-seated geological process, the hydrothermal activity, the formation environments of granite-type uranium deposit, the source of pyrite and its influence on uranium mineralization, the uranium ore-forming of Sinian-Cambrian periods and devonian period formations, and the simple model of uranium ore-forming. On the basis of the relationship of uranium mineralization with geophysical field, as well as the ore-forming geological environments inferred by gravity and magnetic field investigation, the physical-geological model is established in order to predicate uranium prospect

  6. Microbial accumulation of uranium

    International Nuclear Information System (INIS)

    Zhang Wei; Dong Faqin; Dai Qunwei

    2005-01-01

    The mechanism of microbial accumulation of uranium and the effects of some factors (including pH, initial uranium concentration, pretreatment of bacteria, and so on) on microbial accumulation of uranium are discussed briefly. The research direction and application prospect are presented. (authors)

  7. Uranium energy dependence

    International Nuclear Information System (INIS)

    Erkes, P.

    1981-06-01

    Uranium supply and demand as projected by the Uranium Institute is discussed. It is concluded that for the industrialized countries, maximum energy independence is a necessity. Hence it is necessary to achieve assurance of supply for uranium used in thermal power reactors in current programs and eventually to move towards breeders

  8. Australian uranium today

    International Nuclear Information System (INIS)

    Fisk, B.

    1978-01-01

    The subject is covered in sections, entitled: Australia's resources; Northern Territory uranium in perspective; the government's decision [on August 25, 1977, that there should be further development of uranium under strictly controlled conditions]; Government legislation; outlook [for the Australian uranium mining industry]. (U.K.)

  9. 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.)

  10. Recycling of reprocessed uranium

    International Nuclear Information System (INIS)

    Randl, R.P.

    1987-01-01

    Since nuclear power was first exploited in the Federal Republic of Germany, the philosophy underlying the strategy of the nuclear fuel cycle has been to make optimum use of the resource potential of recovered uranium and plutonium within a closed fuel cycle. Apart from the weighty argument of reprocessing being an important step in the treatment and disposal of radioactive wastes, permitting their optimum ecological conditioning after the reprocessing step and subsequent storage underground, another argument that, no doubt, carried weight was the possibility of reducing the demand of power plants for natural uranium. In recent years, strategies of recycling have emerged for reprocessed uranium. If that energy potential, too, is to be exploited by thermal recycling, it is appropriate to choose a slightly different method of recycling from the one for plutonium. While the first generation of reprocessed uranium fuel recycled in the reactor cuts down natural uranium requirement by some 15%, the recycling of a second generation of reprocessed, once more enriched uranium fuel helps only to save a further three per cent of natural uranium. Uranium of the second generation already carries uranium-232 isotope, causing production disturbances, and uranium-236 isotope, causing disturbances of the neutron balance in the reactor, in such amounts as to make further fabrication of uranium fuel elements inexpedient, even after mixing with natural uranium feed. (orig./UA) [de

  11. High-Resolution Mineralogical Characterization and Biogeochemical Modeling of Uranium Reduction Pathways at the NABIR Field-Research Center

    International Nuclear Information System (INIS)

    David R. Veblen; Chen Zhu; Lee Krumholz; Claudine Stirling; Emma-Kate Potter; Alex N. Halliday

    2004-01-01

    The effectiveness and feasibility of bioremediation at the field scale cannot be fully assessed until the mechanisms of immobilization and U speciation in the solid matrix are resolved. However, characterization of the immobilized U and its valence states is extremely difficult, because microbially mediated mineral precipitates are generally nanometer (nm)-sized, poorly crystalline, or amorphous. We are developing combined field emission gun--scanning electron microscopy (FEG-SEM, at Indiana University) and FEG transmission electron microscopy (TEM, at Hopkins) to detect and isolate uranium containing phases; (1) method developments for TEM sample preparations and parallel electron energy loss spectroscopy (EELS) determination of uranium valence; and (2) to determine the speciation, fate, reactivity, valence states of immobilized uranium, using the state-of-the-art 300-kV, FEG-TEM. We have obtained preliminary results on contaminated sediments from Area 3 at the Oak Ridge Field Research Center (FRC). TEM results show that the sediments contain numerous minerals, including quartz, mica/clay (muscovite and/or illite), rutile, ilmenite, zircon, and an Al-Sr-Ce-Ca phosphate mineral, none of which contain uranium above the EDS detection limit. Substantial U (up to ∼2 wt.%) is, however, clearly associated with two materials: (1) the Fe oxyhydroxide and (2) clots of a chemically complex material that is likely a mixture of several nm-scale phases. The Fe oxyhydroxide was identified as goethite from its polycrystalline SAED pattern and EDS analysis showing it to be very Fe-rich; the aggregate also displays one of several morphologies that are common for goethite. U is strongly sorbed to goethite in the FRC sediment, and the ubiquitous association with phosphorous suggests that complexes containing both U and P may play an important role in that sorption. Results from bulk analysis and SEM had previously demonstrated the association of U with Fe and thus suggested that U

  12. Uranium in tertiary stream channels, Lake Frome area, South Australia

    International Nuclear Information System (INIS)

    Brunt, D.A.

    1978-01-01

    Uranium exploration over a wide area of the Southern Frome Embayment, South Australia, has defined a number of Lower Tertiary fluvial palacochannels incised in older rocks. The buried channels contain similar stratigraphic sequences of interbedded sand, silt, and clay, probably derived from the adjacent uranium-rich Olary Province. Uranium mineralization is pervasive within two major palacochannels, and four small uranium deposits have been found in the basal sands of these channel sequences, at the margins of extensive tongues of limonitic sand. A genetic model is proposed suggesting formation by a uraniferous geochemical cell which migrated down the stream gradient and concentrated uranium on its lateral margins adjacent to the channel bank

  13. A regional multi-scale 3-D geological model of the Eastern Sub-Athabasca Basement, Canada: Implications for vectoring towards unconformity-type uranium deposits

    International Nuclear Information System (INIS)

    Annesley, I.; Reilkoff, B.; Takacs, E.; Hajnal, Z.; Pandit, B.

    2014-01-01

    The Proterozoic Athabasca Basin of northern Saskatchewan is one of the most important mining districts in Canada; hosting the world’s highest grade uranium deposits and prospects. In the basin, many of the near-surface deposits have been discovered; hence new ore deposits at greater depths need to be discovered. To help make new discoveries, 3D geological modelling is being carried out. Here, we present our multidisciplinary approach, whereby a 3D geological model of the eastern sub- Athabasca basement of northern Saskatchewan (i.e. the eastern and western Wollaston domains, the Wollaston-Mudjatik Transition Zone (WMTZ), and the Mudjatik Domain) was developed in the common earth environment. The project was directed towards building a robust 3D model(s) of the upper 3-5 km of the Earth’s crust in three different scales: deposit-, district-, and regional-scale, using the GOCAD software platform (Paradigm). Our eastern sub-Athabasca basement model is constrained by both geological studies and geophysical techniques, such as topographic, outcrop, drill hole, petrophysical, and petrological data, along with geophysical potential field, electrical, and highresolution regional seismic data, in order to better understand the regional- to district-scale tectonics and controls on the uranium mineral system(s) operating pre-, syn-, and post-Athabasca deposition. The resulting data were interpreted and visualized as 3D-surfaces and bodies in GOCAD. This model reveals a framework of key lithological contacts, major high-strain zones, and the setting of unconformity-type uranium deposits. As a result, this new knowledge is being used to identify key exploration vectoring criteria for unconformity-type, magmatic, and metamorphic/ metasomatic uranium deposits and to delineate new exploration targets in the basin. Hence, this regional-scale 3D GOCAD model can be utilized as a guide for exploration activities within the region (e.g. picking new drill targets). As well, this 3D

  14. Crystal field effect in the uranium compounds - model calculations for CsUF/sub 6/, Cs/sub 2/UCl/sub 6/ and UCl/sub 4/

    Energy Technology Data Exchange (ETDEWEB)

    Gajek, Z.; Mulak, J.; Faucher, M.

    1987-01-01

    A practical crystal field model allowing one to estimate the crystal field parameters from first principles is presented and applied to the actinide compounds. The model results directly from the renormalization (and reduction) procedure of the true Schroedinger equation for an effective Hamiltonian acting on the 5f spin-orbitals only. In practice this approach becomes convergent with the ab initio model of Newman. Three ionic uranium compounds: CsUF/sub 6/, Cs/sub 2/UCl/sub 6/ and UCl/sub 4/ have served as examples of the application. The results obtained, particularly for the first two compounds, are in good agreement with the experimental data. The contributions of different mechanisms responsible for the crystal field effect are discussed.

  15. Crystal field effect in the uranium compounds - model calculations for CsUF6, Cs2UCl6 and UCl4

    International Nuclear Information System (INIS)

    Gajek, Z.; Mulak, J.

    1987-01-01

    A practical crystal field model allowing one to estimate the crystal field parameters from first principles is presented and applied to the actinide compounds. The model results directly from the renormalization (and reduction) procedure of the true Schroedinger equation for an effective Hamiltonian acting on the 5f spin-orbitals only. In practice this approach becomes convergent with the ab initio model of Newman. Three ionic uranium compounds: CsUF 6 , Cs 2 UCl 6 and UCl 4 have served as examples of the application. The results obtained, particularly for the first two compounds, are in good agreement with the experimental data. The contributions of different mechanisms responsible for the crystal field effect are discussed. (author)

  16. 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

  17. High loading uranium plate

    International Nuclear Information System (INIS)

    Wiencek, T.C.; Domagala, R.F.; Thresh, H.R.

    1990-01-01

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

  18. PROCESS OF RECOVERING URANIUM

    Science.gov (United States)

    Carter, J.M.; Larson, C.E.

    1958-10-01

    A process is presented for recovering uranium values from calutron deposits. The process consists in treating such deposits to produce an oxidlzed acidic solution containing uranium together with the following imparities: Cu, Fe, Cr, Ni, Mn, Zn. The uranium is recovered from such an impurity-bearing solution by adjusting the pH of the solution to the range 1.5 to 3.0 and then treating the solution with hydrogen peroxide. This results in the precipitation of uranium peroxide which is substantially free of the metal impurities in the solution. The peroxide precipitate is then separated from the solution, washed, and calcined to produce uranium trioxide.

  19. Uranium dioxide-sodium interactions. Development of a theoretical model. Fitting of this model to the experimental results

    International Nuclear Information System (INIS)

    Syrmalenios, Panayotis

    1973-01-01

    This research thesis addresses the issue of safety of fast neutron reactors, and more particularly is a contribution of the study of mechanisms of interaction between molten fuel and sodium. It aims at developing tools of prediction of consequences of three main types of accidents: local fusion of a fuel rod and contact of the fuel with the surrounding sodium, failure of an assembly due to the fusion of several rods and fuel-coolant interaction within the assembly, and fuel-coolant interaction at the level of the reactor core. The author first proposes a bibliographical analysis of experimental and theoretical studies related to this issue of interaction between a hot body and a cold liquid, and of its consequences. Then, he introduces a mathematical model and its resolution method, and reports the use of the associated code (Corfou) for the interpretation of experimental results: expulsion of cold sodium column by expansion of an overheated sodium mass, fusion of a rod by Joule effect, interaction between UO_2 molten by high frequency with liquid sodium. Finally, the author discusses a comparison between the Corfou code and other models which are being currently developed [fr

  20. Extraction of uranium from seawater

    International Nuclear Information System (INIS)

    Kanno, M.

    1977-01-01

    The nuclear power generation is thought to be very important in Japan. However, known domestic uranium resources in Japan are very rare. So, extraction of uranium from sea water have been carried out since 1962 at Japan Tobacco and Salt Public Corporation. There are a number of results obtained also by Kyoto University, Shikoku Govenment Industrial Research Institute, Tokyo University and others. In order to investigate the technical and economical feasibility of extraction of uranium and other resources from sea water, a research program was started in fiscal 1975, sponsored by the Ministry of International Trade and Industry with the budget of about $440,000. In this program, the conceptional design of two types of model plants, the ''column type'' and the ''tidal type'' was drawn on the design bases set up with available information. It was found that there has been several problems waiting solution, but there were no technically fatal problems. Adsorption tests were carried out with adsorbents of more than eleven types, including titanium hydroxide, and it was found that titanium hydroxide made by titanyl surphate and urea had the largest adsorption capacity of uranium among them. Elution experiments were performed only with ammonium carbonate and the efficiency at the temperature of 60 0 C showed three times higher than that of 20 0 C. A few long term column operation was conducted, mainly with the adsorbent of granulated titanium hydroxide for 15-60 days. The maximum yield of uranium throughout the adsorption and elution operation was over 20% and macimum concentration of uranium in eluate was 7 ppm

  1. 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

  2. A modelling exercise on the importance of ternary alkaline earth carbonate species of uranium(VI) in the inorganic speciation of natural waters

    International Nuclear Information System (INIS)

    Vercouter, Thomas; Reiller, Pascal E.; Ansoborlo, Eric; Février, Laureline; Gilbin, Rodolphe; Lomenech, Claire; Philippini, Violaine

    2015-01-01

    Highlights: • The U(VI) speciation in natural waters has been modelled through a modelling exercise. • The results evidence the importance of alkaline earth U(VI) carbonate complexes. • Possible solubility-controlling phases were reported and discussed. • The differences were related to the choice and reliability of thermodynamic data. • Databases need to be improved for reliable U(VI) speciation calculations. - Abstract: Predictive modelling of uranium speciation in natural waters can be achieved using equilibrium thermodynamic data and adequate speciation software. The reliability of such calculations is highly dependent on the equilibrium reactions that are considered as entry data, and the values chosen for the equilibrium constants. The working group “Speciation” of the CETAMA (Analytical methods establishment committee of the French Atomic Energy commission, CEA) has organized a modelling exercise, including four participants, in order to compare modellers’ selections of data and test thermodynamic data bases regarding the calculation of U(VI) inorganic speciation. Six different compositions of model waters were chosen so that to check the importance of ternary alkaline earth carbonate species of U(VI) on the aqueous speciation, and the possible uranium solid phases as solubility-limiting phases. The comparison of the results from the participants suggests (i) that it would be highly valuable for end-users to review thermodynamic constants of ternary carbonate species of U(VI) in a consistent way and implement them in available speciation data bases, and (ii) stresses the necessary care when using data bases to avoid biases and possible erroneous calculations

  3. Model for the behaviour of thorium and uranium fuels at pelletization; Modelo para o comportamento de microesferas combustiveis de torio e uranio na peletizacao

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira Neto, Ricardo Alberto

    2000-11-15

    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)

  4. 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.

  5. 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.)

  6. Combined Estimation of Hydrogeologic Conceptual Model, Parameter, and Scenario Uncertainty with Application to Uranium Transport at the Hanford Site 300 Area

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Philip D.; Ye, Ming; Rockhold, Mark L.; Neuman, Shlomo P.; Cantrell, Kirk J.

    2007-07-30

    This report to the Nuclear Regulatory Commission (NRC) describes the development and application of a methodology to systematically and quantitatively assess predictive uncertainty in groundwater flow and transport modeling that considers the combined impact of hydrogeologic uncertainties associated with the conceptual-mathematical basis of a model, model parameters, and the scenario to which the model is applied. The methodology is based on a n extension of a Maximum Likelihood implementation of Bayesian Model Averaging. Model uncertainty is represented by postulating a discrete set of alternative conceptual models for a site with associated prior model probabilities that reflect a belief about the relative plausibility of each model based on its apparent consistency with available knowledge and data. Posterior model probabilities are computed and parameter uncertainty is estimated by calibrating each model to observed system behavior; prior parameter estimates are optionally included. Scenario uncertainty is represented as a discrete set of alternative future conditions affecting boundary conditions, source/sink terms, or other aspects of the models, with associated prior scenario probabilities. A joint assessment of uncertainty results from combining model predictions computed under each scenario using as weight the posterior model and prior scenario probabilities. The uncertainty methodology was applied to modeling of groundwater flow and uranium transport at the Hanford Site 300 Area. Eight alternative models representing uncertainty in the hydrogeologic and geochemical properties as well as the temporal variability were considered. Two scenarios represent alternative future behavior of the Columbia River adjacent to the site were considered. The scenario alternatives were implemented in the models through the boundary conditions. Results demonstrate the feasibility of applying a comprehensive uncertainty assessment to large-scale, detailed groundwater flow

  7. Spectroscopy and DFT studies of uranyl carbonate, rutherfordine, UO2CO3: a model for uranium transport, carbon dioxide sequestration, and seawater species

    Science.gov (United States)

    Kalashnyk, N.; Perry, D. L.; Massuyeau, F.; Faulques, E.

    2017-12-01

    Several optical microprobe experiments of the anhydrous uranium carbonate—rutherfordine—are presented in this work and compared to periodic density functional theory results. Rutherfordine is the simplest uranyl carbonate and constitutes an ideal model system for the study of the rich uranium carbonate family relevant for environmental sustainability. Micro-Raman, micro-reflectance, and micro-photoluminescence (PL) spectroscopy studies have been carried out in situ on native, micrometer-sized crystals. The sensitivity of these techniques is sufficient to analyze minute amounts of samples in natural environments without using x-ray analysis. In addition, very intense micro-PL and micro-reflectance spectra that were not reported before add new results on the ground and excited states of this mineral. The optical gap value determined experimentally is found at about 2.6-2.8 eV. Optimized geometry, band structure, and phonon spectra have been calculated. The main vibrational lines are identified and predicted by this theoretical study. This work is pertinent for optical spectroscopy, for identification of uranyl species in various environmental settings, and for nuclear forensic analysis.

  8. Conceptual model of fractured aquifer of Uranium Deposit in Caetité, Bahia: implications for groundwater flow

    International Nuclear Information System (INIS)

    Silva, Liliane Ferreira da

    2015-01-01

    The studied area is represented by the uraniferous district of Lagoa Real, located in the center-south of Bahia State, Brazil. The region is set in a semiarid climate context, with hot and dry weather parameters, with hydric deficit along all months of the year and high aridity index. Rural population is affected on drought periods since small agriculture and animal rearing are the main economic activities which are vulnerable in dry seasons. Groundwater represents the main supply source considering that most surface water sources are temporary and only exhibit flow in rainy periods. The main aquifer system present on the region is fractured, and the presence of groundwater flow occurs through the discontinuities of the rock considering that the rock mass corresponds to the set formed by the rock matrix and all its discontinuities (fractures, foliations, discordance, etc). In this sense, the main purpose of this Master Dissertation was to develop a conceptual model for the aquifer system, through the geotechnical characterization of discontinuities, once these structures allow the secondary porosity of the medium. Hydrochemical data hand out as complement for physical characterization for the behavioral interpretation of the aquifer. The aquifer system is unconfined, however, presents points of stagnation of flow forming compartments without communication with the surrounding areas. According to the International Society of Rock Mechanics ISRM method, which consist on qualitative and quantitative characterization of discontinuities of rock mass scanlines were constructed, systematically, describing, the following structure parameters: attitude, spacing, persistence, openness, infilling and roughness. From the results analysis it could be concluded that the aquifer system is composed of three discontinuities sets: one set which dips to NE, second set dipping to SW-W-NW and the last set sub-horizontal. The first and second sets are responsible for the aquifer

  9. 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...

  10. Application of a catchment evolution model to the prediction of long-term erosion on the spoil heap at Ranger uranium mine. Supervising Scientist report 132

    International Nuclear Information System (INIS)

    Willgoose, G.

    1998-01-01

    There is a need to assess the long-term stability of engineered landforms associated with the rehabilitation of Ranger Uranium Mine, Northern Territory, Australia, as it is a requirement that mill tailings must be contained for periods in excess of 1000 years. The geomorphic model, SIBERIA, is calibrated on hydrology and erosion data collected by a combination of monitoring and rainfall simulation experiments on the waste rock dumps of Ranger. Preliminary analysis of Ranger's preferred above-grade and below-grade rehabilitation options suggests that erosion of the order of 7-8 m will occur on the structure in a period of 1000 years. This depth of erosion may be sufficient to compromise the integrity of the containment. It is shown that SIBERIA has significant advantages over steady-state erosion models. Suggestions are made for the design that will enhance the stability of the structure and extend the structural life of the containment

  11. 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

  12. 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

  13. 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.

  14. Uranium recovery from seawater

    International Nuclear Information System (INIS)

    Bitte, J.; Fremery, M.I.; Kellner, A.; Schroeer, K.; Knippenberg, W.

    1984-09-01

    The present publication describes the development work of a process to recover uranium from seawater and the proposition of a commercial demonstration plant. The essential components of this process are verified in the laboratory scale as well as in some field tests. A detailed engineering design for a model plant in a semi-technical scale to allow field tests in the marine environment is also presented. These field tests are expected to produce more realistic data on the technical and economical feasibility of the proposed technology. Production cost estimates based on state-of-the-art technology lie around 250 Dollar/1b U 3 O 8 . However, the effect of a corresponding uranium price increase on electricity costs are comparable to cost increases in coal operated power plants caused by the desulfurisation of coal. Further reductions of the production costs in the range below 150 Dollar/1b U 3 O 8 seem possible through special research efforts in the area of sorber development and concept design. (orig.) [de

  15. 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

  16. 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

  17. 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)

  18. 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

  19. An experimental and modeling study of grain-scale uranium desorption from field-contaminated sediments and the potential influence of microporosity on mass-transfer

    Science.gov (United States)

    Stoliker, D.; Liu, C.; Kent, D. B.; Zachara, J. M.

    2012-12-01

    The aquifer below the 300-Area of the Hanford site (Richland, WA, USA) is plagued by a persistent plume of dissolved uranium (U(VI)) in excess of the Environmental Protection Agency drinking water maximum contamination level even after the removal of highly contaminated sediments. The aquifer sediments in the seasonally saturated lower vadose zone act as both a source and sink for uranium during stage changes in the nearby Columbia River. Diffusion limitation of uranium mass-transfer within these sediments has been cited as a potential cause of the plume's persistence. Equilibrium U(VI) sorption is a strong function of variable chemical conditions, especially carbonate, hydrogen, and uranyl ion activities. Field-contaminated sediments from the site require up to 1,000 hours to reach equilibrium in static batch reactors. Increases in U(VI) concentrations over longer time-scales result from changes in chemical conditions, which drive reactions with sediments that favor U(VI) desorption. Grain-scale U(VI) sorption/desorption rates are slow, likely owing to diffusion of U(VI) and other solutes through intra-granular pore domains. In order to improve understanding of the impact of intra-granular diffusion and chemical reactions controlling grain-scale U(VI) release, experiments were conducted on individual particle size fractions of a single set of constant chemical conditions with multiple stop-flow events, were similar for all size fractions displacement from equilibrium and multiple diffusion domains were described with a two-parameter lognormal distribution of mass-transfer rate coefficients. Parameters describing mass transfer were the same for all size fractions reaction models calibrated with individual size fractions predicted U(VI) and chemical composition as a function of time for the bulk sediment sample. Volumes of pores less than 2.4 nm, quantified using nitrogen adsorption-desorption isotherms, were the same for all size fractions < 2 mm, nearly double

  20. Corrosion of Al-7075 by uranium hexafluoride

    International Nuclear Information System (INIS)

    1989-01-01

    The results of the Al-7075 corrosion by uranium hexafluoride are presented in this work. The kinetic study shows that corrosion process occurs by two temperature dependent mechanism and that the alloy can be safely used up to 140 0 C. The corrosion film is formed by uranium oxifluoride with variable composition in depth. Two alternative corrosion models are proposed in order to explain the experimental results, as well as the tests taht will be carried out to confirm one of them [pt

  1. Exact Solution of Fractional Diffusion Model with Source Term used in Study of Concentration of Fission Product in Uranium Dioxide Particle

    International Nuclear Information System (INIS)

    Fang Chao; Cao Jianzhu; Sun Lifeng

    2011-01-01

    The exact solution of fractional diffusion model with a location-independent source term used in the study of the concentration of fission product in spherical uranium dioxide (UO 2 ) particle is built. The adsorption effect of the fission product on the surface of the UO 2 particle and the delayed decay effect are also considered. The solution is given in terms of Mittag-Leffler function with finite Hankel integral transformation and Laplace transformation. At last, the reduced forms of the solution under some special physical conditions, which is used in nuclear engineering, are obtained and corresponding remarks are given to provide significant exact results to the concentration analysis of nuclear fission products in nuclear reactor. (nuclear physics)

  2. Rupture of Model 48Y UF6 cylinder and release of uranium hexafluoride, Sequoyah Fuels Facility, Gore, Oklahoma, January 4, 1986. Volume 1

    International Nuclear Information System (INIS)

    1986-02-01

    At 11:30 a.m. on January 4, 1986, a Model 48Y UF 6 cylinder filled with uranium hexafluoride (UF 6 ) ruptured while it was being heated in a steam chest at the Sequoyah Fuels Conversion Facility near Gore, Oklahoma. One worker died because he inhaled hydrogen fluoride fumes, a reaction product of UF 6 and airborne moisture. Several other workers were injured by the fumes, but none seriously. Much of the facility complex and some offsite areas to the south were contaminated with hydrogen fluoride and a second reaction product, uranyl fluoride. The interval of release was approximately 40 minutes. The cylinder, which had been overfilled, ruptured while it was being heated because of the expansion of UF 6 as it changed from the solid to the liquid phase. The maximum safe capacity for the cylinder is 27,560 pounds of product. Evidence indicates that it was filled with an amount exceeding this limit. 18 figs

  3. The uranium cycle

    International Nuclear Information System (INIS)

    Ferguson, J.

    1988-01-01

    In identifying uranium provinces, and, more importantly, mineralized zones within these provinces, it is of paramount importance to attempt to trace the geochemical behaviour of an element through all stages of Earth's evolution. Aspects that need to be addressed in this regard include solar abundance levels and fractionation processes during accretion, changing patterns of crustal evolution, effects of an evolving atmosphere, and the weathering cycle. Abundance patterns and partition coefficients of some of the siderophile elements in mantle rocks lend support to a multistage accretionary process. Lack of a terrestrial record in the first 500 Ma necessitates that lunar models be invoked, which suggests that early fractionation of a mafic/ultramafic magma resulted in an anorthositic crust. Fractionation of the mantle and transfer of materials to the upper levels must be central to any model invoked for development of the crust. Given high heat flow conditions in the early Archaean it would seem inescapable that the process of sea floor spreading and plate tectonics was an ongoing process. If the plate tectonic model is taken back to 3500 Ma, and assuming current speading rates, then about half of the mantle has passed through the irreversible differentiation cycle. Arguments in support of recycled material must be balanced against mantle metasomatism effects. With the associated advent of partial melting of the mantle material a partitioning of minor and trace elements into the melt fraction would take place. The early primitive mafic and ultramafic komatiites exemplify this feature by concentrating U and Th by a factor of 5 compared to chondritic abundances. It is of tantamount importance to understand the generation of the magmas in order to predict which are the 'fertile' bodies in terms of radioelement concentrations. In that the granitoid magmas image their source compositions, the association of high radioelements will primarily be source-dependent. Uranium

  4. Titrimetric determination of uranium

    International Nuclear Information System (INIS)

    Florence, T.M.

    1989-01-01

    Titrimetric methods are almost invariably used for the high precision assay of uranium compounds, because gravimetric methods are nonselective, and not as reliable. Although precipitation titrations have been used, for example with cupferron and ferrocyanide, and chelate titrations with EDTA and oxine give reasonable results, in practice only redox titrations find routine use. With all redox titration methods for uranium a precision of 01 to 02 percent can be achieved, and precisions as high as 0.003 percent have been claimed for the more refined techniques. There are two types of redox titrations for uranium in common use. The first involves the direct titration of uranium (VI) to uranium (IV) with a standard solution of a strong reductant, such as chromous chloride or titanous chloride, and the second requires a preliminary reduction of uranium to the (IV) or (III) state, followed by titration back to the (VI) state with a standard oxidant. Both types of redox titrations are discussed. 4 figs

  5. Politics of Uranium

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    Uranium is the most political of all the elements, the material for the production of both the large amounts of electricity and the most destructive weapons in the world. The problems that its dual potential creates are only now beginning to become evident. Author Norman Moss looks at this situation and sheds light on many of the questions that emerge. The nuclear issue always comes back to how much uranium there is, what can be done with it, and which countries have it. Starting with a concise history of uranium and explaining its technology in terms the nonspecialist can understand, The Politics of Uranium considers the political issues that technical arguments obscure. It tells the little-known story of the international uranium cartel, explains the entanglements of governments with the uranium trade, and describes the consequences of wrong decisions and blunders-especially the problems of nuclear waste. It also examines the intellectual and emotional roots of the anti-nuclear movement

  6. Uranium resources and supply

    International Nuclear Information System (INIS)

    Cameron, J.

    1973-01-01

    The future supply of uranium has to be considered against a background of forecasts of uranium demand over the next decades which show increases of a spectacular nature. It is not necessary to detail these forecasts, they are well known. A world survey by the Joint NEA/IAEA Working Party on 'Uranium Resources, Production and Demand', completed this summer, indicates that from a present production level of just over 19,000 tonnes uranium per year, the demand will rise to the equivalent of an annual production requirement of 50,000 tonnes uranium by 1980, 100,000 by 1985 and 180,000 by 1990. Few, if any, mineral production industries have been called upon to plan for a near tenfold increase in production in a space of about 15 years as these forecasts imply. This might possibly mean that, perhaps, ten times the present number of uranium mines will have to be planned and engineered by 1990

  7. How much uranium

    International Nuclear Information System (INIS)

    Kenward, M.

    1976-01-01

    Comment is made on the latest of a series of reports on world uranium resources from the OECD's Nuclear Energy Agency and the UN's International Atomic Energy Agency (Uranium resources, production and demand (including other nuclear fuel cycle data), published by the Organisation for Economic Cooperation and Development, Paris). The report categories uranium reserves by their recovery cost and looks at power demand and the whole of the nuclear fuel cycle, including uranium enrichment and spent fuel reprocessing. The effect that fluctuations in uranium prices have had on exploration for new uranium resources is considered. It is stated that increased exploration is essential considering the long lead times involved but that thanks to today's higher prices there are distinct signs that prospecting activities are increasing again. (U.K.)

  8. Uranium Mill Tailings Management

    International Nuclear Information System (INIS)

    Nelson, J.D.

    1982-01-01

    This book presents the papers given at the Fifth Symposium on Uranium Mill Tailings Management. Advances made with regard to uranium mill tailings management, environmental effects, regulations, and reclamation are reviewed. Topics considered include tailings management and design (e.g., the Uranium Mill Tailings Remedial Action Project, environmental standards for uranium mill tailings disposal), surface stabilization (e.g., the long-term stability of tailings, long-term rock durability), radiological aspects (e.g. the radioactive composition of airborne particulates), contaminant migration (e.g., chemical transport beneath a uranium mill tailings pile, the interaction of acidic leachate with soils), radon control and covers (e.g., radon emanation characteristics, designing surface covers for inactive uranium mill tailings), and seepage and liners (e.g., hydrologic observations, liner requirements)

  9. Geochemical exploration for uranium

    International Nuclear Information System (INIS)

    1988-01-01

    This Technical Report is designed mainly to introduce the methods and techniques of uranium geochemical exploration to exploration geologists who may not have had experience with geochemical exploration methods in their uranium programmes. The methods presented have been widely used in the uranium exploration industry for more than two decades. The intention has not been to produce an exhaustive, detailed manual, although detailed instructions are given for a field and laboratory data recording scheme and a satisfactory analytical method for the geochemical determination of uranium. Rather, the intention has been to introduce the concepts and methods of uranium exploration geochemistry in sufficient detail to guide the user in their effective use. Readers are advised to consult general references on geochemical exploration to increase their understanding of geochemical techniques for uranium

  10. Classification of Uranium deposits

    International Nuclear Information System (INIS)

    Dahlkamp, F.J.

    1978-01-01

    A listing of the recognized types of uranium mineralization shows nineteen determinable types out of which only six can be classified as of economic significance at present: Oligomiitic quartz pebble conglomerates, sandstone types, calcretes, intra-intrusive types, hydrothermal veins, veinlike types. The different types can be genetically related to prevalent geological environments, i.e. 1. the primary uranium occurrences formed by endogenic processes, 2. the secondary derived from the primary by subsequent exogenic processes, 3. the tertiary occurrences are assumed to be formed by endogenic metamorphic processes, although little is known about the behaviour of the uranium during the metamorphosis and therefore the metallogenesis of this tertiary uranium generation is still vague. A metallotectonic-geochronologic correlation of the uranium deposits shows a distinct affinity of the uranium to certain geological epochs: The Upper Archean, Lower Proterozoic, the Hercynian and, in a less established stage, the Upper Proterozoic. (orig.) 891 HP/orig. 892 MKO [de

  11. Uranium Newsletter. No. 1

    International Nuclear Information System (INIS)

    1987-03-01

    The new Uranium Newsletter is presented as an IAEA annual newsletter. The organization of the IAEA and its involvement with uranium since its founding in 1957 is described. The ''Red Book'' (Uranium Resources, Production and Demand) is mentioned. The Technical Assistance Programme of the IAEA in this field is also briefly mentioned. The contents also include information on the following meetings: The Technical Committee Meeting on Uranium Deposits in Magmatic and Metamorphic Rocks, Advisory Group Meeting on the Use of Airborne Radiometric Data, and the Technical Committee Meeting on Metallogenesis. Recent publications are listed. Current research contracts in uranium exploration are mentioned. IAEA publications on uranium (in press) are listed also. Country reports from the following countries are included: Australia, Brazil, Canada, China (People's Republic of), Denmark, Finland, Germany (Federal Republic of), Malaysia, Philippines, Portugal, South Africa (Republic of), Spain, Syrian Arab Republic, United Kingdom, United States of America, Zambia, and Greece. There is also a report from the Commission of European Communities

  12. Uranium purchases report 1992

    International Nuclear Information System (INIS)

    1993-01-01

    Data reported by domestic nuclear utility companies in their responses to the 1991 and 1992 ''Uranium Industry Annual Survey,'' Form EIA-858, Schedule B ''Uranium Marketing Activities,are provided in response to the requirements in the Energy Policy Act 1992. Data on utility uranium purchases and imports are shown on Table 1. Utility enrichment feed deliveries and secondary market acquisitions of uranium equivalent of US DOE separative work units are shown on Table 2. Appendix A contains a listing of firms that sold uranium to US utilities during 1992 under new domestic purchase contracts. Appendix B contains a similar listing of firms that sold uranium to US utilities during 1992 under new import purchase contracts. Appendix C contains an explanation of Form EIA-858 survey methodologies with emphasis on the processing of Schedule B data

  13. 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.

  14. 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.

  15. Scale-up of the mixer of a mixer-settler model used in a uranium solvent extraction process

    International Nuclear Information System (INIS)

    Santana, A.O. de; Dantas, C.C.

    1995-01-01

    Scale-up relations were obtained for the mixer of a box type mixer-settler used in an uranium extraction process from chloridric leaches. Three box type mixers of different sizes and with the same geometry were used for batch and continuous-flow experiments. The correlations between the extraction rate and he specific power input, D/T ratio(=turbine diameter/mixer width) and residence time were experimentally determined. The results showed that the extraction rate increases with the power input at a constant D/T ratio equal to 1/3, remaining however, independent from the mixer size for a specific value of the power input. This behaviour was observed for power input values ranging from 100 to 750 W/m 3 . (author) 8 refs.; 8 figs.; 4 tabs

  16. New french uranium mineral species

    International Nuclear Information System (INIS)

    Branche, G.; Chervet, J.; Guillemin, C.

    1952-01-01

    In this work, the authors study the french new uranium minerals: parsonsite and renardite, hydrated phosphates of lead and uranium; kasolite: silicate hydrated of uranium and lead uranopilite: sulphate of uranium hydrated; bayleyite: carbonate of uranium and of hydrated magnesium; β uranolite: silicate of uranium and of calcium hydrated. For all these minerals, the authors give the crystallographic, optic characters, and the quantitative chemical analyses. On the other hand, the following species, very rare in the french lodgings, didn't permit to do quantitative analyses. These are: the lanthinite: hydrated uranate oxide; the α uranotile: silicate of uranium and of calcium hydrated; the bassetite: uranium phosphate and of hydrated iron; the hosphuranylite: hydrated uranium phosphate; the becquerelite: hydrated uranium oxide; the curite: oxide of uranium and lead hydrated. Finally, the authors present at the end of this survey a primary mineral: the brannerite, complex of uranium titanate. (author) [fr

  17. Uranium demand. An exploration challenge

    Energy Technology Data Exchange (ETDEWEB)

    Roux, A J.A.

    1976-10-01

    The estimated world resources of uranium as well as the estimated consumption of uranium over the next 25 years are briefly discussed. Attention is also given to the prospecting for uranium in South Africa and elsewhere in the world.

  18. 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.

  19. 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

  20. 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

  1. Uranium industry annual, 1988

    International Nuclear Information System (INIS)

    1989-01-01

    This report presents data on US uranium raw materials and marketing activities of the domestic uranium industry. It contains aggregated data reported by US companies on the ''Uranium Industry Annual Survey'' (1988), Form EIA-858, and historical data from prior data collections and other pertinent sources. The report was prepared by the Energy Information Administration (EIA), the independent agency for data collection and analysis with the US Department of Energy

  2. Gold and uranium extraction

    International Nuclear Information System (INIS)

    James, G.S.; Davidson, R.J.

    1977-01-01

    A process for extracting gold and uranium from an ore containing them both comprising the steps of pulping the finely comminuted ore with a suitable cyanide solution at an alkaline pH, acidifying the pulp for uranium dissolution, adding carbon activated for gold recovery to the pulp at a suitable stage, separating the loaded activated carbon from the pulp, and recovering gold from the activated carbon and uranium from solution

  3. Uranium mine ventilation

    International Nuclear Information System (INIS)

    Katam, K.; Sudarsono

    1982-01-01

    Uranium mine ventilation system aimed basically to control and decreasing the air radioactivity in mine caused by the radon emanating from uranium ore. The control and decreasing the air ''age'' in mine, with adding the air consumption volume, increasing the air rate consumption, closing the mine-out area; using closed drainage system. Air consumption should be 60m 3 /minute for each 9m 2 uranium ore surfaces with ventilation rate of 15m/minute. (author)

  4. Pine Creek uranium province

    International Nuclear Information System (INIS)

    Bower, M.B.; Needham, R.S.; Page, R.W.; Stuart-Smith, P.G.; Wyborn, L.A.I.

    1985-01-01

    The objective of this project is to help establish a sound geological framework of the Pine Creek region through regional geological, geochemical and geophysical studies. Uranium ore at the Coronation Hill U-Au mine is confined to a wedge of conglomerate in faulted contact with altered volcanics. The uranium, which is classified as epigenetic sandstone type, is derived from a uranium-enriched felsic volcanic source

  5. Chemical thermodynamics of uranium

    International Nuclear Information System (INIS)

    Grenthe, I.; Fuger, J.; Lemire, R.J.; Muller, A.B.; Nguyen-Trung Cregu, C.; Wanner, H.

    1992-01-01

    A comprehensive overview on the chemical thermodynamics of those elements that are of particular importance in the safety assessment of radioactive waste disposal systems is provided. This is the first volume in a series of critical reviews to be published on this subject. The book provides an extensive compilation of chemical thermodynamic data for uranium. A description of procedures for activity corrections and uncertainty estimates is given. A critical discussion of data needed for nuclear waste management assessments, including areas where significant gaps of knowledge exist is presented. A detailed inventory of chemical thermodynamic data for inorganic compounds and complexes of uranium is listed. Data and their uncertainty limits are recommended for 74 aqueous complexes and 199 solid and 31 gaseous compounds containing uranium, and on 52 aqueous and 17 solid auxiliary species containing no uranium. The data are internally consistent and compatible with the CODATA Key Values. The book contains a detailed discussion of procedures used for activity factor corrections in aqueous solution, as well as including methods for making uncertainty estimates. The recommended data have been prepared for use in environmental geochemistry. Containing contributions written by experts the chapters cover various subject areas such a s: oxide and hydroxide compounds and complexes, the uranium nitrides, the solid uranium nitrates and the arsenic-containing uranium compounds, uranates, procedures for consistent estimation of entropies, gaseous and solid uranium halides, gaseous uranium oxides, solid phosphorous-containing uranium compounds, alkali metal uranates, uncertainties, standards and conventions, aqueous complexes, uranium minerals dealing with solubility products and ionic strength corrections. The book is intended for nuclear research establishments and consulting firms dealing with uranium mining and nuclear waste disposal, as well as academic and research institutes

  6. Uranium in Canada

    International Nuclear Information System (INIS)

    1985-09-01

    In 1974 the Minister of Energy, Mines and Resources (EMR) established a Uranium Resource Appraisal Group (URAG) within EMR to audit annually Canada's uranium resources for the purpose of implementing the federal government's uranium export policy. A major objective of this policy was to ensure that Canadian uranium supplies would be sufficient to meet the needs of Canada's nuclear power program. As projections of installed nuclear power growth in Canada over the long term have been successively revised downwards (the concern about domestic security of supply is less relevant now than it was 10 years ago) and as Canadian uranium supply capabilities have expanded significantly. Canada has maintained its status as the western world's leading exporter of uranium and has become the world's leading producer. Domestic uranium resource estimates have increased to 551 000 tonnes U recoverable from mineable ore since URAG completed its last formal assessment (1982). In 1984, Canada's five primary uranium producers employed some 5800 people at their mining and milling operations, and produced concentrates containing some 11 170 tU. It is evident from URAG's 1984 assessment that Canada's known uranium resources, recoverable at uranium prices of $150/kg U or less, are more than sufficient to meet the 30-year fuelling requirements of those reactors that are either in opertaion now or committed or expected to be in-service by 1995. A substantial portion of Canada's identified uranium resources, recoverable within the same price range, is thus surplus to Canadian needs and available for export. Sales worth close to $1 billion annually are assured. Uranium exploration expenditures in Canada in 1983 and 1984 were an estimated $41 million and $35 million, respectively, down markedly from the $128 million reported for 1980. Exploration drilling and surface development drilling in 1983 and 1984 were reported to be 153 000 m and 197 000 m, respectively, some 85% of which was in

  7. Research and Development of Multiphysics Models in Support of the Conversion of the High Flux Isotope Reactor to Low Enriched Uranium Fuel

    International Nuclear Information System (INIS)

    Bodey, Isaac T.; Curtis, Franklin G.; Arimilli, Rao V.; Ekici, Kivanc; Freels, James D.

    2015-01-01

    The findings presented in this report are results of a five year effort led by the RRD Division of the ORNL, which is focused on research and development toward the conversion of the High Flux Isotope Reactor (HFIR) fuel from high-enriched uranium (HEU) to low-enriched uranium (LEU). This report focuses on the tasks accomplished by the University of Tennessee Knoxville (UTK) team from the Department of Mechanical, Aerospace, and Biomedical Engineering (MABE) that provided expert support in multiphysics modeling of complex problems associated with the LEU conversion of the HFIR reactor. The COMSOL software was used as the main computational modeling tool, whereas Solidworks was also used in support of computer-aided-design (CAD) modeling of the proposed LEU fuel design. The UTK research has been governed by a statement of work (SOW), which was updated annually to clearly define the specific tasks reported herein. Ph.D. student Isaac T. Bodey has focused on heat transfer and fluid flow modeling issues and has been aided by his major professor Dr. Rao V. Arimilli. Ph.D. student Franklin G. Curtis has been focusing on modeling the fluid-structure interaction (FSI) phenomena caused by the mechanical forces acting on the fuel plates, which in turn affect the fluid flow in between the fuel plates, and ultimately the heat transfer, is also affected by the FSI changes. Franklin Curtis has been aided by his major professor Dr. Kivanc Ekici. M.Sc. student Adam R. Travis has focused two major areas of research: (1) on accurate CAD modeling of the proposed LEU plate design, and (2) reduction of the model complexity and dimensionality through interdimensional coupling of the fluid flow and heat transfer for the HFIR plate geometry. Adam Travis is also aided by his major professor, Dr. Kivanc Ekici. We must note that the UTK team, and particularly the graduate students, have been in very close collaboration with Dr. James D. Freels (ORNL technical monitor and mentor) and have

  8. Research and Development of Multiphysics Models in Support of the Conversion of the High Flux Isotope Reactor to Low Enriched Uranium Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Bodey, Isaac T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Curtis, Franklin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Arimilli, Rao V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ekici, Kivanc [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Freels, James D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-11-01

    The findings presented in this report are results of a five year effort led by the RRD Division of the ORNL, which is focused on research and development toward the conversion of the High Flux Isotope Reactor (HFIR) fuel from high-enriched uranium (HEU) to low-enriched uranium (LEU). This report focuses on the tasks accomplished by the University of Tennessee Knoxville (UTK) team from the Department of Mechanical, Aerospace, and Biomedical Engineering (MABE) that provided expert support in multiphysics modeling of complex problems associated with the LEU conversion of the HFIR reactor. The COMSOL software was used as the main computational modeling tool, whereas Solidworks was also used in support of computer-aided-design (CAD) modeling of the proposed LEU fuel design. The UTK research has been governed by a statement of work (SOW), which was updated annually to clearly define the specific tasks reported herein. Ph.D. student Isaac T. Bodey has focused on heat transfer and fluid flow modeling issues and has been aided by his major professor Dr. Rao V. Arimilli. Ph.D. student Franklin G. Curtis has been focusing on modeling the fluid-structure interaction (FSI) phenomena caused by the mechanical forces acting on the fuel plates, which in turn affect the fluid flow in between the fuel plates, and ultimately the heat transfer, is also affected by the FSI changes. Franklin Curtis has been aided by his major professor Dr. Kivanc Ekici. M.Sc. student Adam R. Travis has focused two major areas of research: (1) on accurate CAD modeling of the proposed LEU plate design, and (2) reduction of the model complexity and dimensionality through interdimensional coupling of the fluid flow and heat transfer for the HFIR plate geometry. Adam Travis is also aided by his major professor, Dr. Kivanc Ekici. We must note that the UTK team, and particularly the graduate students, have been in very close collaboration with Dr. James D. Freels (ORNL technical monitor and mentor) and have

  9. 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

  10. Uranium production from phosphates

    International Nuclear Information System (INIS)

    Ketzinel, Z.; Folkman, Y.

    1979-05-01

    According to estimates of the world's uranium consumption, exploitation of most rich sources is expected by the 1980's. Forecasts show that the rate of uranium consumption will increase towards the end of the century. It is therefore desirable to exploit poor sources