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Sample records for estimating uranium partition

  1. Estimating Uranium Partition Coefficients from Laboratory Adsorption Isotherms

    International Nuclear Information System (INIS)

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

    2002-01-01

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

  2. Uranium partitioning under acidic conditions in a sandy soil aquifer

    International Nuclear Information System (INIS)

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

    1995-01-01

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

  3. Consistent Estimation of Partition Markov Models

    Directory of Open Access Journals (Sweden)

    Jesús E. García

    2017-04-01

    Full Text Available The Partition Markov Model characterizes the process by a partition L of the state space, where the elements in each part of L share the same transition probability to an arbitrary element in the alphabet. This model aims to answer the following questions: what is the minimal number of parameters needed to specify a Markov chain and how to estimate these parameters. In order to answer these questions, we build a consistent strategy for model selection which consist of: giving a size n realization of the process, finding a model within the Partition Markov class, with a minimal number of parts to represent the process law. From the strategy, we derive a measure that establishes a metric in the state space. In addition, we show that if the law of the process is Markovian, then, eventually, when n goes to infinity, L will be retrieved. We show an application to model internet navigation patterns.

  4. Estimation of potential uranium resources

    International Nuclear Information System (INIS)

    Curry, D.L.

    1977-09-01

    Potential estimates, like reserves, are limited by the information on hand at the time and are not intended to indicate the ultimate resources. Potential estimates are based on geologic judgement, so their reliability is dependent on the quality and extent of geologic knowledge. Reliability differs for each of the three potential resource classes. It is greatest for probable potential resources because of the greater knowledge base resulting from the advanced stage of exploration and development in established producing districts where most of the resources in this class are located. Reliability is least for speculative potential resources because no significant deposits are known, and favorability is inferred from limited geologic data. Estimates of potential resources are revised as new geologic concepts are postulated, as new types of uranium ore bodies are discovered, and as improved geophysical and geochemical techniques are developed and applied. Advances in technology that permit the exploitation of deep or low-grade deposits, or the processing of ores of previously uneconomic metallurgical types, also will affect the estimates

  5. 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

  6. Partitioning ratio of depleted uranium during a melt decontamination by arc melting

    International Nuclear Information System (INIS)

    Min, Byeong Yeon; Choi, Wang Kyu; Oh, Won Zin; Jung, Chong Hun

    2008-01-01

    In a study of the optimum operational condition for a melting decontamination, the effects of the basicity, slag type and slag composition on the distribution of depleted uranium were investigated for radioactively contaminated metallic wastes of iron-based metals such as stainless steel (SUS 304L) in a direct current graphite arc furnace. Most of the depleted uranium was easily moved into the slag from the radioactive metal waste. The partitioning ratio of the depleted uranium was influenced by the amount of added slag former and the slag basicity. The composition of the slag former used to capture contaminants such as depleted uranium during the melt decontamination process generally consists of silica (SiO 2 ), calcium oxide (CaO) and aluminum oxide (Al 2 O 3 ). Furthermore, calcium fluoride (CaF 2 ), magnesium oxide (MgO), and ferric oxide (Fe 2 O 3 ) were added to increase the slag fluidity and oxidative potential. The partitioning ratio of the depleted uranium was increased as the amount of slag former was increased. Up to 97% of the depleted uranium was captured between the ingot phase and the slag phase. The partitioning ratio of the uranium was considerably dependent on the basicity and composition of the slag. The optimum condition for the removal of the depleted uranium was a basicity level of about 1.5. The partitioning ratio of uranium was high, exceeding 5.5x10 3 . The slag formers containing calcium fluoride (CaF 2 ) and a high amount of silica proved to be more effective for a melt decontamination of stainless steel wastes contaminated with depleted uranium

  7. The Influence of Oxygen and Sulfur on Uranium Partitioning Into the Core

    Science.gov (United States)

    Moore, R. D., Jr.; Van Orman, J. A.; Hauck, S. A., II

    2017-12-01

    Uranium, along with K and Th, may provide substantial long-term heating in planetary cores, depending on the magnitude of their partitioning into the metal during differentiation. In general, non-metallic light elements are known to have a large influence on the partitioning of trace elements, and the presence of sulfur is known to enhance the partitioning of uranium into the metal. Data from the steelmaking literature indicate that oxygen also enhances the solubility of oxygen in liquid iron alloys. Here we present experimental data on the partitioning of U between immiscible liquids in the Fe-S-O system, and use these data along with published metal-silicate partitioning data to calibrate a quantitative activity model for U in the metal. We also determined partition coefficients for Th, K, Nb, Nd, Sm, and Yb, but were unable to fully constrain activity models for these elements with available data. A Monte Carlo fitting routine was used to calculate U-S, U-O, and U-S-O interaction coefficients, and their associated uncertainties. We find that the combined interaction of uranium with sulfur and oxygen is predominant, with S and O together enhancing the solubility of uranium to a far greater degree than either element in isolation. This suggests that uranium complexes with sulfite or sulfate species in the metal. For a model Mars core composition containing 14 at% S and 5 at% O, the metal/silicate partition coefficient for U is predicted to be an order of magnitude larger than for a pure Fe-Ni core.

  8. Probabilistic estimates of US uranium supply

    International Nuclear Information System (INIS)

    Piepel, G.F.; Long, L.W.; McLaren, R.A.; Ford, C.E.

    1981-02-01

    This report develops and presents probabilistic estimates of total US uranium supply. The word supply is used in the broad sense that both uranium quantity and cost are of interest. Cost implies minimum acceptable selling price rather than market price. Specifically, four types of probability distributions are developed: (1) quantity of US uranium; (2) cost of US uranium; (3) quantity of US uranium available at or below a certain cost; and (4) cost of US uranium given a certain consumption. In this report, uranium refers to recoverable U 3 O 8 (endowment adjusted for mining recovery and milling losses) occurring in both reserve and potential deposits meeting minimum size requirements with minimum grade above 0.01%. Cost includes operating and capital costs, taxes, profit, and cost capital. This definition of cost is often used to better denote this meaning. This definition of cost is contrasted with forward costs, that exclude sunk costs, taxes, and return on investment. Consumption refers to uranium that has been used from the current time to any point in the future. Uranium quantity and consumption are expressed in short tons, while full recovery costs are stated in constant 1980 dollars per pound

  9. The partitioning of uranium and neptunium onto hydrothermally altered concrete

    International Nuclear Information System (INIS)

    Zhao, P.; Allen, P.G.; Sylwester, E.R.; Viani, B.E.

    2000-01-01

    Partition coefficients (K d ) of U(VI) and Np(V) on untreated and hydrothermally altered concrete were measured in 0.01 M NaCl and 0.01 M NaHCO 3 solutions as functions of concentration of the radionuclides, pH, and time. The partition coefficients for both U(VI) and Np(V) on hydrothermally altered concrete are significantly lower than those on untreated concrete. The partition of both U(VI) and Np(V) are pH dependent, although the pH dependence does not appear to reflect precipitation of U and Np-bearing phases. Both sorption and precipitation are likely processes controlling partitioning of U to concrete; sorption is the most likely process controlling the partitioning of Np to concrete. The presence of 0.01 M carbonate species in solution decreases K d of U(VI) for both hydrothermally altered and untreated concrete from ≥ 10 4 mL/g to ∝ 400 to 1000 mL/g indicating a significant impact on U(VI) sorption. In contrast, the presence of carbonate only reduced the K d of Np(V) by one order of magnitude or less. X-ray absorption spectroscopy analysis of U/concrete mixtures at different pHs and times indicate that uranyl ions are partitioned as monomeric species on untreated concrete, but oligomeric species on hydrothermally altered concrete. Similar analysis of Np/concrete mixtures shows that about half of the partitioned Np(V) is reduced to Np(IV) over a period of 6 months. (orig.)

  10. Estimation of octanol/water partition coefficients using LSER parameters

    Science.gov (United States)

    Luehrs, Dean C.; Hickey, James P.; Godbole, Kalpana A.; Rogers, Tony N.

    1998-01-01

    The logarithms of octanol/water partition coefficients, logKow, were regressed against the linear solvation energy relationship (LSER) parameters for a training set of 981 diverse organic chemicals. The standard deviation for logKow was 0.49. The regression equation was then used to estimate logKow for a test of 146 chemicals which included pesticides and other diverse polyfunctional compounds. Thus the octanol/water partition coefficient may be estimated by LSER parameters without elaborate software but only moderate accuracy should be expected.

  11. Plutonium--uranium partitioning; alternate flowsheet Plutonium Reclamation Facility. [SEPHIS

    Energy Technology Data Exchange (ETDEWEB)

    Fort, L.A.

    1975-12-01

    The SEPHIS computer program was used to predict the transient and steady-state concentrations in a stage-wise scheme for the Pu reclamation solvent extraction system. With the aid of the computer an alternative flowsheet for Pu--U partitioning was constructed. The goal of the alternative program is to reduce Pu losses from the initial stripping column and reduce the quantity of Pu-bearing wastes from the solvent extraction system. (JSR)

  12. Partitioning of plutonium and uranium in aqueous medium using hydroxyurea as reducing agent

    International Nuclear Information System (INIS)

    Sivakumar, P.; Subba Rao, R.V.; Meenakshi, S.

    2012-01-01

    A new process for the partitioning of plutonium and uranium during the reprocessing of spent fuel discharged from fast reactor was optimised using hydroxyurea (HU) as a reductant. Stoichiometric ratio of HU required for the reduction of Pu(IV) was studied. The effect of concentration of uranium, plutonium and acidity on the distribution ratio (Kd) of Pu in the presence of HU was studied. The effect of HU in further purification of Pu such as solvent extraction and precipitation of plutonium as oxalate was also studied. The results of the study indicate that Pu and U can be separated from each other using HU as reductant. (author)

  13. Speculative resources of uranium. A review of International Uranium Resources Evaluation Project (IUREP) estimates 1982-1983

    International Nuclear Information System (INIS)

    1983-01-01

    On a country by country basis the International Uranium Resources Evaluation Project (IUREP) estimates 1982-1983 are reviewed. Information provided includes exploration work, airborne survey, radiometric survey, gamma-ray spectrometric survey, estimate of speculative resources, uranium occurrences, uranium deposits, uranium mineralization, agreements for uranium exploration, feasibilities studies, geological classification of resources, proposed revised resource range, production estimate of uranium

  14. Uranium-thorium disequilibria and partitioning on melting of garnet peridotite

    International Nuclear Information System (INIS)

    Beattie, P.

    1993-01-01

    The abundances of isotopes in the 238 U decay series can be used as both tracers and chronometers of magmatic processes. In the subsolidus asthenosphere, the activity of each daughter isotope (defined as the product of its concentration and decay constant, and denoted by parentheses) is assumed to be equal to that of its parent. By contrast, ( 230 Th/ 238 U) is greater than unity in most recent mid-ocean-ridge and ocean-island basalts, implying that thorium is more incompatible (that is, it is partitioned into the melt phase more strongly) than uranium. Melting of spinel peridotite cannot produce the ( 230 Th) excesses, because measured partition coefficients for pyroxenes and olivine demonstrate that uranium is more incompatible than thorium for this rock. Here I report garnet-melt partitioning data which show that for this mineral-melt pair thorium does behave more incompatibility than uranium, thus supporting the suggestion that mid-ocean-ridge basalts (MORB) are produced by melting initiated at depths where garnet is stable. Using these data, I show that the observed ( 230 Th/ 238 U) ratios of MORB and most ocean-island basalts can be explained by slow, near-fractional melting initiated in the garnet stability field. (author)

  15. Energy analysis applied to uranium resource estimation

    International Nuclear Information System (INIS)

    Mortimer, N.D.

    1980-01-01

    It is pointed out that fuel prices and ore costs are interdependent, and that in estimating ore costs (involving the cost of fuels used to mine and process the uranium) it is necessary to take into account the total use of energy by the entire fuel system, through the technique of energy analysis. The subject is discussed, and illustrated with diagrams, under the following heads: estimate of how total workable resources would depend on production costs; sensitivity of nuclear electricity prices to ore costs; variation of net energy requirement with ore grade for a typical PWR reactor design; variation of average fundamental cost of nuclear electricity with ore grade; variation of cumulative uranium resources with current maximum ore costs. (U.K.)

  16. 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.

  17. Determination of uranium partition coefficients of a semi-arid soil in Bahia

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Heloisa H.F.; Pontedeiro, Elizabeth M.; Su, Jian, E-mail: heloisa@lasme.coppe.ufrj.br, E-mail: bettinadulley@hotmail.com, E-mail: sujian@lasme.coppe.ufrj.br [Coordenacao dos Cursos de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Lab. de Simulacao e Metodos de Engenharia; Dourado, Eneida R.G., E-mail: eneida@inb.gov.br [Industrias Nucleares do Brasil (INB), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    In mining and processing industries, the subsurface is one of the most vulnerable compartments to environmental contamination. Understanding the interactions between soil and contaminants is critical for predicting the possible environmental impacts caused by mining and milling operations. One of the main parameters used for this purpose is the partition (or distribution) coefficient, K{sub d}, which allows a relatively simple modeling approach by grouping various sorption phenomena into a single value. However, this parameter is strongly influenced by the physical and chemical characteristics of the medium, such as soil type, pH and solution composition. Thus, this study aims to assess the values of K{sub d} for uranium of typical soils from Bahia's semi-arid region using two different types of solute, one being a standard solution of uranyl acetate and one the liquor of uranium generated during processing. To calculate this parameter, batch adsorption experiments were carried out and adsorption isotherms (linear, Langmuir and Freundlich) were constructed using the Mathematica software. Results obtained for a single type of soil showed reduced values of K{sub d} for a liquor containing uranium when compared to values obtained with the uranyl acetate solution. This indicates that uranium from liquor is less adsorbed onto soil particles, and hence may move more quickly into the subsurface. (author)

  18. Determination of uranium partition coefficients of a semi-arid soil in Bahia

    International Nuclear Information System (INIS)

    Fernandes, Heloisa H.F.; Pontedeiro, Elizabeth M.; Su, Jian

    2013-01-01

    In mining and processing industries, the subsurface is one of the most vulnerable compartments to environmental contamination. Understanding the interactions between soil and contaminants is critical for predicting the possible environmental impacts caused by mining and milling operations. One of the main parameters used for this purpose is the partition (or distribution) coefficient, K d , which allows a relatively simple modeling approach by grouping various sorption phenomena into a single value. However, this parameter is strongly influenced by the physical and chemical characteristics of the medium, such as soil type, pH and solution composition. Thus, this study aims to assess the values of K d for uranium of typical soils from Bahia's semi-arid region using two different types of solute, one being a standard solution of uranyl acetate and one the liquor of uranium generated during processing. To calculate this parameter, batch adsorption experiments were carried out and adsorption isotherms (linear, Langmuir and Freundlich) were constructed using the Mathematica software. Results obtained for a single type of soil showed reduced values of K d for a liquor containing uranium when compared to values obtained with the uranyl acetate solution. This indicates that uranium from liquor is less adsorbed onto soil particles, and hence may move more quickly into the subsurface. (author)

  19. Methodology for uranium resource estimates and reliability

    International Nuclear Information System (INIS)

    Blanchfield, D.M.

    1980-01-01

    The NURE uranium assessment method has evolved from a small group of geologists estimating resources on a few lease blocks, to a national survey involving an interdisciplinary system consisting of the following: (1) geology and geologic analogs; (2) engineering and cost modeling; (3) mathematics and probability theory, psychology and elicitation of subjective judgments; and (4) computerized calculations, computer graphics, and data base management. The evolution has been spurred primarily by two objectives; (1) quantification of uncertainty, and (2) elimination of simplifying assumptions. This has resulted in a tremendous data-gathering effort and the involvement of hundreds of technical experts, many in uranium geology, but many from other fields as well. The rationality of the methods is still largely based on the concept of an analog and the observation that the results are reasonable. The reliability, or repeatability, of the assessments is reasonably guaranteed by the series of peer and superior technical reviews which has been formalized under the current methodology. The optimism or pessimism of individual geologists who make the initial assessments is tempered by the review process, resulting in a series of assessments which are a consistent, unbiased reflection of the facts. Despite the many improvements over past methods, several objectives for future development remain, primarily to reduce subjectively in utilizing factual information in the estimation of endowment, and to improve the recognition of cost uncertainties in the assessment of economic potential. The 1980 NURE assessment methodology will undoubtly be improved, but the reader is reminded that resource estimates are and always will be a forecast for the future

  20. Methods for the estimation of uranium ore reserves

    International Nuclear Information System (INIS)

    1985-01-01

    The Manual is designed mainly to provide assistance in uranium ore reserve estimation methods to mining engineers and geologists with limited experience in estimating reserves, especially to those working in developing countries. This Manual deals with the general principles of evaluation of metalliferous deposits but also takes into account the radioactivity of uranium ores. The methods presented have been generally accepted in the international uranium industry

  1. 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

  2. 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

  3. Estimating uranium resources and production. A guide to future supply

    International Nuclear Information System (INIS)

    Taylor, D.M.; Haeussermann, W.

    1983-01-01

    Nuclear power can only continue to grow if sufficient fuel, uranium, is available. Concern has been expressed that, in the not too distant future, the supply of uranium may be inadequate to meet reactor development. This will not be the case. Uranium production capability, actual and planned, is the main indicator of short- and medium-term supply. However, for the longer term, uranium resource estimates and projections of the possible rate of production from the resource base are important. Once an estimate has been made of the resources contained in a deposit, several factors influence the decision to produce the uranium and also the rates at which the uranium can be produced. The effect of these factors, which include uranium market trends and ever increasing lead times from discovery to production, must be taken into account when making projections of future production capability and before comparing these with forecasts of future uranium requirements. The uranium resource base has developed over the last two decades mainly in response to dramatically changing projections of natural uranium requirements. A study of this development and the changes in production, together with the most recent data, shows that in the short- and medium-term, production from already discovered resources should be sufficient to cover any likely reactor requirements. Studies such as those undertaken during the International Uranium Resources Evaluation Project, and others which project future discovery rates and production, are supported by past experience in resource development in showing that uranium supply could continue to meet demand until well into the next century. The uranium supply potential has lessened the need for the early large-scale global introduction of the breeder reactor

  4. Analytical control of reducing agents on uranium/plutonium partitioning at purex process

    International Nuclear Information System (INIS)

    Araujo, Izilda da Cruz de

    1995-01-01

    Spectrophotometric methods for uranium (IV), hydrazine (N 2 H 4 ) and its decomposition product hydrazoic acid(HN 3 ), and hydroxylamine (NH 2 OH) determinations were developed aiming their applications for the process control of CELESTE I installation at IPEN/CNEN-SP. These compounds are normally present in the U/Pu partitioning phase of the spent nuclear treatment via PUREX process. The direct spectrophotometry was used for uranium (IV) analysis in nitric acid-hydrazine solutions based on the absorption measurement at 648 nm. The azomethine compound formed by reaction of hydrazine and p-dimethylamine benzaldehyde with maximum absorption at 457 nm was the basis for the specific analytical method for hydrazine determination. The hydrazoic acid analysis was performed indirectly by its conversion into ferric azide complex with maximum absorption at 465 nm. The hydroxylamine detection was accomplished based on its selective oxidation to nitrous acid which is easily analyzed by the reaction with Griess reagent. The resulted azocompound gas a maximum absorption at 520 nm. The sensibility of 1,4x10 -6 M for U(IV) with 0,8% of precision, 1,6x10 -6 M for hydrazine with 0,8% of precision, 2,3x10 -6 M hydrazoic acid with 0,9% of precision and 2,5x10 -6 M for hydroxylamine with 0,8% of precision were achieved. The interference studies have shown that each reducing agent can be determined in the presence of each other without any interference. Uranium(VI) and plutonium have also shown no interference in these analysis. The established methods were adapted to run inside glove-boxes by using an optical fiber colorimetry and applied to process control of the CELESTE I installation. The results pointed out that the methods are reliable and safety in order to provide just-in-time information about process conditions. (author)

  5. Study on interference of technetium in spectrophotometric estimation of uranium

    International Nuclear Information System (INIS)

    Revathi, P.; Saipriya, K.; Madhavan Kutty, V.K.; Srinivasa Rao, G.; Vijayakumar, N.; Kumar, T.

    2015-01-01

    Estimation of uranium is essential for process control purposes as well as to arrive optimum parameters for further waste management in reprocessing industry. Uranium estimation is done by spectrophotometry using ammonium thiocyanate, DBM, PAR and Br-PADAP as chromogenic reagents for colour development. Extractive spectrophotometry can also be used to eliminate some of the interfering ions. During inter method comparison, technetium was found to be interfering in the thiocyanate spectrophotometry. This study is an effort to find out the extent of technetium interference in the estimation of uranium by spectrophotometry using the above said chromogenic reagents. (author)

  6. Estimation of uranium GI absorption fractions for children and adults

    International Nuclear Information System (INIS)

    Chen, J.; Lariviere, D.; Timmins, R.; Verdecchia, K.

    2011-01-01

    Uranium is ubiquitously found in drinking water and food. The gastrointestinal tract absorption fraction (f 1 ) is an important parameter in risk assessment of uranium burdens from ingestion. Although absorption of uranium from ingestion has been studied extensively in the past, human data concerning children and adults are still limited. In a previous study based on measurements of uranium concentration in 73 bone-ash samples collected by Health Canada, the absorption fractions for uranium ingestion were determined to be 0.093 ± 0.113 for infants, and 0.050 ± 0.032 for young children ranging from 1 to 7 y of age. To extend the study, a total of 69 bone-ash samples were selected for children and adults ranging from 7 to 25 y of age and residing in the same Canadian community that is known to have an elevated level of uranium in its drinking water supply. For each bone-ash sample, the total uranium concentration was measured by inductively coupled plasma mass spectrometry. To solve uranium transfer in the biokinetic model for uranium given in International Commission of Radiological Protection (ICRP) Publication 69 with estimated daily uranium intake, the program WinSAAM v3.0.1 was used. The absorption fractions were determined to be 0.030 ± 0.022 for children (7-18 y) and 0.021 ± 0.015 for adults (18-25 y). For anyone more than 18 y of age, the estimated f 1 value for uranium agree well with the ICRP recommended value of 0.02. Published by Oxford Univ. Press on behalf of the Canadian Government 2010. (authors)

  7. Relative estimation of the mineral ages using uranium migration

    International Nuclear Information System (INIS)

    Danis, A.

    1990-01-01

    Using the uranium fission track micro mapping technique the correlation between the age and uranium migration from inclusions was studied. It is shown that during geological time, as function of the mineral, its age and its uranium migration speed, the pattern of the track, clusters corresponding to the uranium inclusions got a typical feature. Thus for a bulk polished geological sample it is possible to establish an age succession of the constituent minerals as a function of the track cluster patterns. Also, it is shown that knowing the migration speed of the uranium in a mineral it is possible to estimate the age of this mineral by measuring the migration distance on the micro mapping. (Author)

  8. Estimation of uranium in some edible and commercial plants

    International Nuclear Information System (INIS)

    Choudhury, S.; Goswami, T.D.

    1992-01-01

    The trace contents of uranium have been estimated in some edible and commercial plants by PTA (particle track analysis) method. The groups of food plants studied are cereals, pulses, underground vegetables, leafy vegetables, and fruit vegetables. The commercial plants and ingredients taken are betel leaves, tobacco leaves, areca nuts, and lime. Among the different samples studied, the average uranium content, in general, is found to vary from 0.25 to 2.67 ppm. (author). 10 refs., 2 tabs., 1 fig

  9. Uncertainty estimation of uranium determination in urine by fluorometry

    International Nuclear Information System (INIS)

    Shakhashiro, A.; Al-Khateeb, S.

    2003-11-01

    In this study an applicable mathematical model is proposed for the estimation of uncertainty in uranium determination by fluorometry in urine sample. The study based on EURACHEM guide for uncertainty estimation. This model was tested on a sample containing 0.02 μg/ml uranium, where calculated uncertainty was 0.007 μg/ml. The sources of uncertainty were shown on fish-bone plane as the following: In addition, the weight of each uncertainty parameter was shown in a histogram: Finally, it was found that the estimated uncertainty by the proposed model was 3 to 4 time more that the usually reported standard deviation. (author)

  10. 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

  11. 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

  12. Estimating the Partition Function Zeros by Using the Wang-Landau Monte Carlo Algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seung-Yeon [Korea National University of Transportation, Chungju (Korea, Republic of)

    2017-03-15

    The concept of the partition function zeros is one of the most efficient methods for investigating the phase transitions and the critical phenomena in various physical systems. Estimating the partition function zeros requires information on the density of states Ω(E) as a function of the energy E. Currently, the Wang-Landau Monte Carlo algorithm is one of the best methods for calculating Ω(E). The partition function zeros in the complex temperature plane of the Ising model on an L × L square lattice (L = 10 ∼ 80) with a periodic boundary condition have been estimated by using the Wang-Landau Monte Carlo algorithm. The efficiency of the Wang-Landau Monte Carlo algorithm and the accuracies of the partition function zeros have been evaluated for three different, 5%, 10%, and 20%, flatness criteria for the histogram H(E).

  13. Soil-water partition coefficients for uranium and thorium: a systematic study of Tummalapalle mining site, India

    International Nuclear Information System (INIS)

    Dalvi, Aditi; Verma, Rakesh; Kumar, Sangita D.; Reddy, A.V.R.

    2012-01-01

    The simplest and most common parameter for modeling radionuclide mobility in soils is the partition coefficient (K d ). The soil-water partition coefficient for radionuclide is affected by numerous geochemical parameters like pH, sorption to clays, presence of organic matter, iron oxides, other soil constituents and the chemical forms of the radionuclide as well as oxidation/reduction conditions and major ion chemistry. In these studies radionuclides uranium and thorium were systematically assessed for their behaviour in the soils from Tummalapalle mining site. Physico-chemical characteristics such as chemical composition, pH, CaCO 3 content and organic carbon were determined for soils and synthetic groundwater samples. Oven dried soil samples (1g) were taken in polycarbonate tube and washed with synthetic ground water till the pH of the supernatant solution remained unchanged. The soil sample was then equilibrated with 30 mL of synthetic ground water spiked with an element of interest. The pH was adjusted to its initial value by addition of small increments of dilute NaOH/HNO 3 . The tubes containing samples were gently shaken for 72 h at room temperature. On completion of the experiment, it was centrifuged using high-speed centrifugation for 30 min and the aqueous phase was separated and analysed. The blank was processed in the same manner without adding soil. Determination of U and Th in the supernatant was carried out using ICPMS. The K d of thorium was found to be two-three order of magnitude higher than that of uranium for both the soil samples assessed in this study. The presence of carbonates and organic carbon in the groundwater has a significant effect on the K d of uranium. The K d values for uranium were found to be hundred fold lower in the presence of carbonates. (author)

  14. Variance of a product with application to uranium estimation

    International Nuclear Information System (INIS)

    Lowe, V.W.; Waterman, M.S.

    1976-01-01

    The U in a container can either be determined directly by NDA or by estimating the weight of material in the container and the concentration of U in this material. It is important to examine the statistical properties of estimating the amount of U by multiplying the estimates of weight and concentration. The variance of the product determines the accuracy of the estimate of the amount of uranium. This paper examines the properties of estimates of the variance of the product of two random variables

  15. Uranium mill tailings and risk estimation

    International Nuclear Information System (INIS)

    Marks, S.

    1984-04-01

    Work done in estimating projected health effects for persons exposed to mill tailings at vicinity properties is described. The effect of the reassessment of exposures at Hiroshima and Nagasaki on the risk estimates for gamma radiation is discussed. A presentation of current results in the epidemiological study of Hanford workers is included. 2 references

  16. Estimation of metallic impurities in uranium by carrier distillation method

    International Nuclear Information System (INIS)

    Page, A.G.; Godbole, S.V.; Deshkar, S.B.; Joshi, B.D.

    1976-01-01

    An emission spectrographic method has been standardised for the estimation of twenty-two metallic impurities in uranium using carrier-distillation technique. Silver chloride with a concentration of 5% has been used as the carrier and palladium and gallium are used as internal standards. Precision and accuracy determinations of the synthetic samples indicate 6-15% deviation for most of the elements. Using the method described here, five uranium reference samples received from C.E.A.-France were analysed. The detection limits obtained for Cd, Co and W are lower than those reported in the literature while limits for the remaining elements are comparable to the values reported. The method is suitable for the chemical quality control analysis of uranium used for the Fast Breeder Test Reactor (FBTR) fuel. (author)

  17. Development of a pyro-partitioning process for long-lived radioactive nuclides. Process test for pretreatment of simulated high-level waste containing uranium

    International Nuclear Information System (INIS)

    Kurata, Masateru; Hijikata, Takatoshi; Kinoshita, Kensuke; Inoue, Tadashi

    2000-01-01

    A pyro-partitioning process developed at CRIEPI requires a pre-treatment process to convert high-level liquid waste to chloride. A combination process of denitration and chlorination has been developed for this purpose. Continuous process tests using simulated high-level waste were performed to certify the applicability of the process. Test results indicated a successful material balance sufficient for satisfying pyro-partitioning process criteria. In the present study, process tests using simulated high-level waste containing uranium were also carried out to prove that the pre-treatment process is feasible for uranium. The results indicated that uranium can be converted to chloride appropriate for the pyro-partitioning process. The material balance obtained from the tests is to be used to revise the process flow diagram. (author)

  18. Estimation of uranium migration parameters in sandstone aquifers.

    Science.gov (United States)

    Malov, A I

    2016-03-01

    The chemical composition and isotopes of carbon and uranium were investigated in groundwater samples that were collected from 16 wells and 2 sources in the Northern Dvina Basin, Northwest Russia. Across the dataset, the temperatures in the groundwater ranged from 3.6 to 6.9 °C, the pH ranged from 7.6 to 9.0, the Eh ranged from -137 to +128 mV, the total dissolved solids (TDS) ranged from 209 to 22,000 mg L(-1), and the dissolved oxygen (DO) ranged from 0 to 9.9 ppm. The (14)C activity ranged from 0 to 69.96 ± 0.69 percent modern carbon (pmC). The uranium content in the groundwater ranged from 0.006 to 16 ppb, and the (234)U:(238)U activity ratio ranged from 1.35 ± 0.21 to 8.61 ± 1.35. The uranium concentration and (234)U:(238)U activity ratio increased from the recharge area to the redox barrier; behind the barrier, the uranium content is minimal. The results were systematized by creating a conceptual model of the Northern Dvina Basin's hydrogeological system. The use of uranium isotope dating in conjunction with radiocarbon dating allowed the determination of important water-rock interaction parameters, such as the dissolution rate:recoil loss factor ratio Rd:p (a(-1)) and the uranium retardation factor:recoil loss factor ratio R:p in the aquifer. The (14)C age of the water was estimated to be between modern and >35,000 years. The (234)U-(238)U age of the water was estimated to be between 260 and 582,000 years. The Rd:p ratio decreases with increasing groundwater residence time in the aquifer from n × 10(-5) to n × 10(-7) a(-1). This finding is observed because the TDS increases in that direction from 0.2 to 9 g L(-1), and accordingly, the mineral saturation indices increase. Relatively high values of R:p (200-1000) characterize aquifers in sandy-clayey sediments from the Late Pleistocene and the deepest parts of the Vendian strata. In samples from the sandstones of the upper part of the Vendian strata, the R:p value is ∼ 24, i.e., sorption processes are

  19. Ammonium uranyl carbonate (AUC) based process of simultaneous partitioning and reconversion for uranium and plutonium in fast breeder reactors (FBRs) fuel reprocessing

    International Nuclear Information System (INIS)

    Govindan, P.; Palamalai, A.; Vijayan, K.S.; Subba Rao, R.V.; Venkataraman, M.; Natarajan, R.

    2013-01-01

    Ammonium uranyl carbonate (AUC) based process of simultaneous partitioning and reconversion for uranium and plutonium is developed for the recovery of uranium and plutonium present in spent fuel of fast breeder reactors (FBRs). Effect of pH on the solubility of carbonates of uranium and plutonium in ammonium carbonate medium is studied. Effect of mole ratios of uranium and plutonium as a function of uranium and plutonium concentration at pH 8.0-8.5 for effective separation of uranium and plutonium to each other is studied. Feasibility of reconversion of plutonium in carbonate medium is also studied. The studies indicate that uranium is selectively precipitated as AUC at pH 8.0-8.5 by adding ammonium carbonate solution leaving plutonium in the filtrate. Plutonium in the filtrate after acidified with concentrated nitric acid could also be precipitated as carbonate at pH 6.5-7.0 by adding ammonium carbonate solution. A flow sheet is proposed and evaluated for partitioning and reconversion of uranium and plutonium simultaneously in the FBR fuel reprocessing. (author)

  20. Estimation of intermediate grade uranium resources. Final report

    International Nuclear Information System (INIS)

    Lambie, F.W.; Kendall, G.R.; Klahn, L.J.; Davis, J.C.; Harbaugh, J.W.

    1980-12-01

    The purpose of this project is to analyze the technique currently used by DOE to estimate intermediate grade uranium (0.01 to 0.05% U 3 O 8 ) and, if possible, suggest alternatives to improve the accuracy and precision of the estimate. There are three principal conclusions resulting from this study. They relate to the quantity, distribution and sampling of intermediate grade uranium. While the results of this study must be validated further, they indicate that DOE may be underestimating intermediate level reserves by 20 to 30%. Plots of grade of U 3 O 8 versus tonnage of ore and tonnage U 3 O 8 indicate grade-tonnage relationships that are essentially log-linear, at least down to 0.01% U 3 O 8 . Though this is not an unexpected finding, it may provide a technique for reducing the uncertainty of intermediate grade endowment. The results of this study indicate that a much lower drill hole density is necessary for DOE to estimate uranium resources than for a mining company to calculate ore resources. Though errors in local estimates will occur, they will tend to cancel over the entire deposit

  1. Nuclear-fuel-cycle education: Module 2. Exploration, reserve estimation, mining, milling, conversion, and properties of uranium

    International Nuclear Information System (INIS)

    Brookins, D.G.

    1981-12-01

    In this module geological and geochemical data pertinent to locating, mining, and milling of uranium are examined. Chapters are devoted to: uranium source characteristics; uranium ore exploration methods; uranium reserve estimation for sandstone deposits; mining; milling; conversion processes for uranium; and properties of uranium, thorium, plutonium and their oxides and carbides

  2. A Convenient Method for Estimation of the Isotopic Abundance in Uranium Bearing Samples

    International Nuclear Information System (INIS)

    AI -Saleh, F.S.; AI-Mukren, Alj.H.; Farouk, M.A.

    2008-01-01

    A convenient and simple method for estimation of the isotopic abundance in some uranium bearing samples using gamma-ray spectrometry is developed using a hyper pure germanium spectrometer and a standard uranium sample with known isotopic abundance

  3. Estimated natural uranium requirements to the year 2000

    International Nuclear Information System (INIS)

    Bennett, L.L.

    1981-01-01

    The future requirements for natural uranium are mainly dependent on the future growth of nuclear energy generation and the types of reactors operated to provide that energy. These topics were examined extensively by the International Nuclear Fuel Cycle Evaluation (INFCE). The resulting projections of nuclear power plant capacity and estimated requirements for natural uranium, other nuclear raw materials and fuel cycle services were presented in the final report of INFCE. The projections from INFCE are the most recent results published by an international body, and can therefore be taken as the most authoritative estimates presently available. The INFCE results have been reviewed in the light of latest trends in national nuclear power capacity figures, and a sub-set of the INFCE results are used as the basis for the demand estimates presented in this article. The principal criteria involved in the selection of this sub-set are the nuclear power growth estimates and the reactor and fuel cycle strategies. These criteria are discussed in the following sections

  4. 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

  5. Covariance Partition Priors: A Bayesian Approach to Simultaneous Covariance Estimation for Longitudinal Data.

    Science.gov (United States)

    Gaskins, J T; Daniels, M J

    2016-01-02

    The estimation of the covariance matrix is a key concern in the analysis of longitudinal data. When data consists of multiple groups, it is often assumed the covariance matrices are either equal across groups or are completely distinct. We seek methodology to allow borrowing of strength across potentially similar groups to improve estimation. To that end, we introduce a covariance partition prior which proposes a partition of the groups at each measurement time. Groups in the same set of the partition share dependence parameters for the distribution of the current measurement given the preceding ones, and the sequence of partitions is modeled as a Markov chain to encourage similar structure at nearby measurement times. This approach additionally encourages a lower-dimensional structure of the covariance matrices by shrinking the parameters of the Cholesky decomposition toward zero. We demonstrate the performance of our model through two simulation studies and the analysis of data from a depression study. This article includes Supplementary Material available online.

  6. A passive technique using SSNTDs for Estimation of thorium to uranium ratios in rocks

    International Nuclear Information System (INIS)

    Kenawy, M.A.; Sayyah, T.A.; Said, A.F.; Hafez, A.F.

    2005-01-01

    A passive technique using plastic nuclear track detectors (CR-39 and LR-115) is presented to estimate Th/U ratios and consequently the thorium and uranium content in granites taken from uranium exploration mines in Egyptian desert. The registration sensitivities of both CR-39 and LR-115 detector for close contact alpha-radiography uranium and thorium concentrations in ppm were computed

  7. Distributed State Estimation Using a Modified Partitioned Moving Horizon Strategy for Power Systems.

    Science.gov (United States)

    Chen, Tengpeng; Foo, Yi Shyh Eddy; Ling, K V; Chen, Xuebing

    2017-10-11

    In this paper, a distributed state estimation method based on moving horizon estimation (MHE) is proposed for the large-scale power system state estimation. The proposed method partitions the power systems into several local areas with non-overlapping states. Unlike the centralized approach where all measurements are sent to a processing center, the proposed method distributes the state estimation task to the local processing centers where local measurements are collected. Inspired by the partitioned moving horizon estimation (PMHE) algorithm, each local area solves a smaller optimization problem to estimate its own local states by using local measurements and estimated results from its neighboring areas. In contrast with PMHE, the error from the process model is ignored in our method. The proposed modified PMHE (mPMHE) approach can also take constraints on states into account during the optimization process such that the influence of the outliers can be further mitigated. Simulation results on the IEEE 14-bus and 118-bus systems verify that our method achieves comparable state estimation accuracy but with a significant reduction in the overall computation load.

  8. Clinical evaluation of the partition model for estimating radiation doses from yttrium-90 microspheres in the treatment of hepatic cancer

    International Nuclear Information System (INIS)

    Ho, S.; Lau, W.Y.; Leung, T.W.T.; Chan, M.; Johnson, P.J.; Li, A.K.C.

    1997-01-01

    Radiation doses to the tumour and non-tumorous liver compartments from yttrium-90 microspheres in the treatment of hepatic cancer, as estimated by a partition model, have been verified by correlation with the actual doses measured with a beta probe at open surgery. The validity of the doses to the lungs, the tumour and non-tumours liver compartment as estimated by the partition model was further evaluated in clinical settings. On the basis of the observation that one of three patients who received more than 30 Gy from a single treatment and one of two patients who received more than 50 Gy from multiple treatments developed radiation pneumonitis, it was deduced that an estimated lung dose 30 Gy as estimated by the partition model and were predicted to develop radiation pneumonitis, did so despite the use of partial hepatic embolization to reduce the degree of lung shunting. Furthermore, a higher radiological response rate and prolonged survival were found in the group of patients who received higher tumour doses, as estimated by the partition model, than in the group with lower estimated tumour doses. Thus the radiation doses estimated by the partition model can be used to predict (a) complication rate, (b) response rate and (c) duration of survival in the same manner as the actual radiation doses measured with a beta probe at open surgery. The partition model has made selective internal radiation therapy using 90 Y microspheres safe and repeatable without laparotomy. (orig.)

  9. Estimating contaminant discharge rates from stabilized uranium tailings embankments

    International Nuclear Information System (INIS)

    Weber, M.F.

    1986-01-01

    Estimates of contaminant discharge rates from stabilized uranium tailings embankments are essential in evaluating long-term impacts of tailings disposal on groundwater resources. Contaminant discharge rates are a function of water flux through tailings covers, the mass and distribution of tailings, and the concentrations of contaminants in percolating pore fluids. Simple calculations, laboratory and field testing, and analytical and numerical modeling may be used to estimate water flux through variably-saturated tailings under steady-state conditions, which develop after consolidation and dewatering have essentially ceased. Contaminant concentrations in water discharging from the tailings depend on tailings composition, leachability and solubility of contaminants, geochemical conditions within the embankment, tailings-water interactions, and flux of water through the embankment. These concentrations may be estimated based on maximum reported concentrations, pore water concentrations, extrapolations of column leaching data, or geochemical equilibria and reaction pathway modeling. Attempts to estimate contaminant discharge rates should begin with simple, conservative calculations and progress to more-complicated approaches, as necessary

  10. Ore reserve estimation of uranium deposit Zirovski vrh

    International Nuclear Information System (INIS)

    Lukacs, E.

    1979-01-01

    The uranium ore deposit Zirovski vrh is in the Permian sediments of Northwest Yugoslavia. Lenticular bodies occur at several stratiform levels in grey, medium-grained sandstone. The ore deposit will be mined entirely by underground methods. It is possible to define three stages of deposit evaluation requiring different densities of exploration effort: preliminary evaluation of in situ ore reserves; evaluation of mineable ore reserves; evaluation of production capability and mine planning. The drilling density increases markedly with each succeeding stage. The optimal drilling density for all three stages of evaluation should be determined, but there is some concern that too close spaced drilling would considerably increase the exploration costs without a corresponding increase in effectiveness. On the other hand, too sparsely spaced drilling may result in some difficulties in following the ore in mining. The paper treats the problem of the density of drilling for evaluation of mineable ore reserves compared to that required for mine planning and mine production capability. The purpose of investigation of mineral raw materials is to define economic deposits (ore bodies). To evaluate the deposit economically an accurate reserve estimate is required. If it is accordingly established that such an estimate is within the degree of admissible error, the purpose of the exploration is satisfied. However, the problem as to whether the drilling grid is sufficiently dense remains, because the majority of estimates of ore reserves do not provide a measure of the reliability of the estimate. (author)

  11. Estimation grade of uranium from drill hole gamma logs

    International Nuclear Information System (INIS)

    Juliao, B.

    1986-01-01

    Radiometric grade of uranium deposits can be determined from drill hole gamma logs. The calculation of uranium oxide content can be obtained with good precision when the uranium ore is in radioactive equilibrium, containing only a small amount of thorium and no interference of potassium. This is the case of uranium ore from the Lagoa Real Uranium Province presented in this paper. The radioactive disequilibrium study in this province were made working over nine hundred samples analised with this special purpose in the CDTN-NUCLEBRAS laboratories. The data obtained indicated that the uranium in the ore is in perfect equilibrium with their daughter gamma emitters. Futhermore, the amount of Th and K is of no significance, so that the gamma counting represents exactly the uranium content of the ore. (author) [pt

  12. Investigation on neptunium behavior in electrolytic partitioning process of uranium and plutonium

    International Nuclear Information System (INIS)

    Zhang Qingxuan; Zhang Jiajun; Tian Baosheng; Jiang Dongliang; Li Zhaoyi; He Jianyu

    1988-01-01

    The electrolytic oxidation-raduction of Np(V, VI) in HNO 3 solution was studied. Experimental results showed that the electrode process of Np(V)-Np(VI) couple is reversible, and the half reaction time of the process mentioned above is about 1.5 minutes under given conditions. The overpotential of reduction of Np(V) is high, which makes it difficult to reduce Np(V) into Np(IV) directly at cathode. Owing to a large quantity of U(IV) produced through electrolysis, it is presaged that neptunium will be mainly in tetravalent state in the electrolytic M-S battery. A new type of electrolytic M-S battery was developed, in which anodes were installed in each settling chamber without any specific anode chamber in the battery. Owing to using of the mechanical stirrer driven by a wheel gear, stage efficiency is high. Demonstration campaign was carried out. It follows from the results that the yield of Pu is 99.90 ∼ 99.99%. Separation factor of U from Pu is 3900 ∼ 33000. Material balance of U and Pu is satisfactory. Heavy accumulation of Np in the battery was observed. Np in the battery is mainly in the tetravalent state. It is believed that it is difficult to recover Np quantitatively from single fluent (e.g. 1BP or 1BU) under normal conditions of partitioning step of the PUREX process

  13. Pyrometallurgical partitioning of uranium and transuranic elements from rare earth elements by electrorefining and reductive extraction

    International Nuclear Information System (INIS)

    Uozumi, Koichi; Kinoshita, Kensuke; Inoue, Tadashi; Storvick, T.S.; Krueger, C.L.; Nabelek, C.R.

    2001-01-01

    High-level liquid waste generated from PUREX reprocessing contains a small amount of transuranic elements, such as Np, Pu, Am, and Cm, with long-lived radioactivities. A pyrometallurgical partitioning process is being developed to recover transuranic elements from such waste. Small amounts of U contained in the high-level liquid waste are also recovered in the process. A key issue for developing the process is effective separation of U and the transuranic elements from the rare-earth elements, because the two elemental groups are chemically analogous. A series of process tests were carried out in the present study to demonstrate that a combination of electrorefining and reductive extraction is useful for separating U and transuranic elements from the rare-earth elements. The results indicate that 99% of U and each transuranic elements is recovered by the combination process as a product, and that the quantity of rare-earth elements contained in the product is smaller than the transuranic elements by weight. The overall mass balance of U and transuranic elements in the system ranged within the experimental errors assigned to sampling and analysis. (author)

  14. Estimation of uranium in different types of water and sand samples by adsorptive stripping voltammetry

    International Nuclear Information System (INIS)

    Bhalke, Sunil; Raghunath, Radha; Mishra, Suchismita; Suseela, B.; Tripathi, R.M.; Pandit, G.G.; Shukla, V.K.; Puranik, V.D.

    2005-01-01

    A method is standardized for the estimation of uranium by adsorptive stripping voltammetry using chloranilic acid (CAA) as complexing agent. The optimum parameters to get best sensitivity and good reproducibility for uranium were 60s adsorption time, pH 1.8, chloranilic acid (2x10 -4 M) and 0.002M EDTA. The peak potential under this condition was found to be -0.03 V. With these optimum parameters a sensitivity of 1.19 nA/nM uranium was observed. Detection limit for this optimum parameter was found to be 0.55 nM. This can be further improved by increasing adsorption time. Using this method, uranium was estimated in different type of water samples such as seawater, synthetic seawater, stream water, tap water, well water, bore well water and process water. This method has also been used for estimation of uranium in sand, organic solvent used for extraction of uranium from phosphoric acid and its raffinate. Sample digestion procedures used for estimation of uranium in various matrices are discussed. It has been observed from the analysis that the uranium peak potentials changes with matrix of the sample, hence, standard addition method is the best method to get reliable and accurate results. Quality assurance of the standardized method is verified by analyzing certified reference water sample from USDOE, participating intercomparison exercises and also by estimating uranium content in water samples both by differential pulse adsorptive stripping voltammetric and laser fluorimetric techniques. (author)

  15. Uranium budget of the Thames River, Ontario, Great Lakes Region: partitioning between dissolved and microorganism components

    International Nuclear Information System (INIS)

    Mann, H.; Fyfe, W.S.

    1987-01-01

    The average level of dissolved U in the Thames River of southern Ontario is 1.45 ± 0.61 ppb, representing about twice the global mean riverine U solute concentration of 0.6 ppb. Systematic seasonal variations of dissolved U occur, peaking over the fall and winter months September-February, contrasting with depressed levels during the spring and summer: the winter and fall peaks correlate with higher discharge rates during thawing and rainfall maxima respectively, and the peak during thawing is probably indigenous to a transient melt-water surge. Whereas variations in discharge rate of up to 100-fold occur over a year, the magnitude of differences in aqueous U are at most a factor of 2, such that the U supply to the river is over-compensated for by extra water in the river system. Algae are abundant in Thames River waters at all seasons, constituting a significant fraction of the suspended > 0.45-μm particulates: they have enhanced U contents of 10 3 -10 5 times that of the river water, and an average of 28,000 ppb U. The average weight of suspended algae in river water is 9.7 mg l -1 (± 6.6 1σ), and these microorganisms carry ∼ 15% of the total riverine U flux. A correlation exists between levels of dissolved U and the U abundance of suspended algae, implying a relatively uniform partitioning of U between algae and water of 2x10 4 . 13 refs.; 7 figs.; 2 tabs

  16. Contribution to the methods for estimating uranium deposits (1963)

    International Nuclear Information System (INIS)

    Carlier, A.

    1964-02-01

    Having defined a deposit of economic value according to the marginal theory, the author discriminates several categories of ore reserves according to the degree of knowledge of the deposit and according to the mining stage where the ore is considered. He dismisses the conventional French classification of 'on sight', 'probable' and 'possible' ore categories and suggests more suitable ones. The 'sensu stricto', ore reserves are those for which the random error can be calculated. The notion of the natural contrast of grades in an ore deposit (absolute dispersion coefficient α) is introduced in relation to this topic. The author considers three types of mining exploration. The first is the random exploration so often met; the second is the logical exploration based on a systematic location of underground works, bore-holes, etc. The third, and hardest to achieve, is the one which minimizes exploration costs for a given level of accuracy. Part of the publication deals with sampling errors such as those resulting from the quartering of a heap of ore (theory of Pierre GY) or those resulting from the use of radiometric measurement of grade. Another part deals with the extension error (entailed by the assimilation of samples to the deposit they are issued from) and gives the essential formulae in order to appraise the random error (Geo-statistics of Matheron). As to the estimator itself the work shows how the disharmony between the ore sample and the associated influence zone can be solved by the way of 'kriging'. The thesis gives numerous examples of the various numerical parameters, characteristics of an uranium deposit (absolute dispersion coefficient) or of an uranium ore (liberation parameter) as well as a few examples of linear correlations between gamma radioactivity and uranium grade. Three complete examples of reserve evaluation are given. The end of the thesis deals with the notion of ruin risk which has to be taken in some cases. A detailed alphabetical index is

  17. South African uranium resource and production capability estimates

    International Nuclear Information System (INIS)

    Camisani-Calzolari, F.A.G.M.; Toens, P.D.

    1980-09-01

    South Africa, along with Canada and the United States, submitted forecasts of uranium capacities and capabilites to the year 2025 for the 1979 'Red Book' edition. This report deals with the methodologies used in arriving at the South African forecasts. As the future production trends of the South African uranium producers cannot be confidently defined, chiefly because uranium is extracted as a by-product of the gold mining industry and is thus highly sensitive to market fluctuations for both uranium and gold, the Evaluation Group of the Atomic Energy Board has carried out numerous forecast exercises using current and historical norms and assuming various degrees of 'adverse', 'normal' and 'most favourable' conditions. The two exercises, which were submitted for the 'Red Book', are shown in the Appendices. This paper has been prepared for presentation to the Working Group on Methodologies for Forecasting Uranium Availability of the NEA/IAEA Steering Group on Uranium Resources [af

  18. 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

  19. 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

  20. Estimation of uranium in bioassay samples of occupational workers by laser fluorimetry

    International Nuclear Information System (INIS)

    Suja, A.; Prabhu, S.P.; Sawant, P.D.; Sarkar, P.K.; Tiwari, A.K.; Sharma, R.

    2010-01-01

    A newly established uranium processing facility has been commissioned at BARC, Trombay. Monitoring of occupational workers at regulars intervals is essential to assess intake of uranium by the workers in this facility. The design and engineering safety features of the plant are such that there is very low probability of uranium getting air borne during normal operations. However, the leakages from the system during routine maintenance of the plant may result in intake of uranium by workers. As per the new biokinetic model for uranium, 63% of uranium entering the blood stream gets directly excreted in urine. Therefore, bioassay monitoring (urinalysis) was recommended for these workers. A group of 21 workers was selected for bioassay monitoring to assess the existing urinary excretion levels of uranium before the commencement of actual work. For this purpose, sample collection kit along with an instruction slip was provided to the workers. Bioassay samples received were wet ashed with conc. nitric acid and hydrogen peroxide to break down the metabolized complexes of uranium and it was co-precipitated with calcium phosphate. Separation of uranium from the matrix was done using ion exchange technique and final activity quantification in these samples was done using laser fluorimeter (Quantalase, Model No. NFL/02). Calibration of the laser fluorimeter is done using 10 ppb uranium standard (WHO, France Ref. No. 180000). Verification of the system performance is done by measuring concentration of uranium in the standards (1 ppb to 100 ppb). Standard addition method was followed for estimation of uranium concentration in the samples. Uranyl ions present in the sample get excited by pulsed nitrogen laser at 337.1 nm, and on de-excitation emit fluorescence light (540 nm) intensity which is measured by the PMT. To estimate the uranium in the bioassay samples, a known aliquot of the sample was mixed with 5% sodium pyrophosphate and fluorescence intensity was measured

  1. Spectrum of Singly Charged Uranium (U II : Theoretical Interpretation of Energy Levels, Partition Function and Classified Ultraviolet Lines

    Directory of Open Access Journals (Sweden)

    Ali Meftah

    2017-06-01

    Full Text Available In an attempt to improve U II analysis, the lowest configurations of both parities have been interpreted by means of the Racah-Slater parametric method, using Cowan codes. In the odd parity, including the ground state, 253 levels of the interacting configurations 5 f 3 7 s 2 + 5 f 3 6 d 7 s + 5 f 3 6 d 2 + 5 f 4 7 p + 5 f 5 are interpreted by 24 free parameters and 64 constrained ones, with a root mean square (rms deviation of 60 cm − 1 . In the even parity, the four known configurations 5 f 4 7 s , 5 f 4 6 d , 5 f 2 6 d 2 7 s , 5 f 2 6 d 7 s 2 and the unknown 5 f 2 6 d 3 form a basis for interpreting 125 levels with a rms deviation of 84 cm − 1 . Due to perturbations, the theoretical description of the higher configurations 5 f 3 7 s 7 p + 5 f 3 6 d 7 p remains unsatisfactory. The known and predicted levels of U II are used for a determination of the partition function. The parametric study led us to a re-investigation of high resolution ultraviolet spectrum of uranium recorded at the Meudon Observatory in the late eighties, of which the analysis was unachieved. In the course of the present study, a number of 451 lines of U II has been classified in the region 2344 –2955 Å. One new level has been established as 5 f 3 6 d 7 p ( 4 I 6 K ( J = 5.5 at 39113.98 ± 0.1 cm − 1 .

  2. A Quantitative Property-Property Relationship for Estimating Packaging-Food Partition Coefficients of Organic Compounds

    DEFF Research Database (Denmark)

    Huang, L.; Ernstoff, Alexi; Xu, H.

    2017-01-01

    Organic chemicals encapsulated in beverage and food packaging can migrate to the food and lead to human exposures via ingestion. The packaging-food (Kpf) partition coefficient is a key parameter to estimate the chemical migration from packaging materials. Previous studies have simply set Kpf to 1...... or 1000, or provided separate linear correlations for several discrete values of ethanol equivalencies of food simulants (EtOH-eq). The aim of the present study is to develop a single quantitative property-property relationship (QPPR) valid for different chemical-packaging combinations and for water...... because only two packaging types are included. This preliminary QPPR demonstrates that the Kpf for various chemicalpackaging-food combinations can be estimated by a single linear correlation. Based on more than 1000 collected Kpf in 15 materials, we will present extensive results for other packaging types...

  3. The fate of uranium contaminants of phosphate fertiliser: chemical partitioning of uranium in two New Zealand soils of volcanic origin and the effect on partitioning of amending one of those soils with uranium

    International Nuclear Information System (INIS)

    Taylor, M.D.

    1998-01-01

    This study assessed the chemical partitioning of U isotopes in Horomanga Sandy Loam and Te Kowhai silt loam, two agricultural soils derived from rhyolitic ash and receiving low level contamination from U impurities in phosphate fertiliser. To simulate future U additions, a sub-sample of the Horomanga soil was amended with 2.259 μg U g -1 soil before sequential extraction. The hypothesis that U additions will be strongly held on to the soil and are not available for leaching or plant uptake was tested. After extraction U was purified and determined by alpha spectrometry. Results were corrected for tailing, background, for losses in the purification process (using 232 U), and for soil moisture. It is concluded that only a small proportion of U in the two type of soils examined was derived from fertiliser and that very little U would be available to plants or to leaching

  4. Selective extraction and subsequent estimation of uranium in membrane optode

    International Nuclear Information System (INIS)

    Joshi, J.M.; Pandey, A.K.; Manchanda, V.K.

    2006-01-01

    In the present work, the possibility of colour changeable optode for uranium detection in groundwater using 2-(5-bromo-2pyridylazo)-5-diethylaminophenol(Br-PADAP) has been explored. The choice for Br-PADAP was based on the fact that it has been used for developing a uranium specific spectrophotometric determination method in the presence of a large excess of thorium

  5. Estimation of Partition Coefficients of Benzene, Toluene, Ethylbenzene, and ρ-Xylene by Consecutive Extraction with Solid Phase Microextraction

    International Nuclear Information System (INIS)

    Eom, In Yong

    2011-01-01

    The results show that the partition coefficients of the BTEX compound can be estimated using the SPME method under the consecutive extraction mode. The proposed technique is much simpler than previously reported methods. Its novelty is that it eliminated the calibration step in the GC/FID, i. e., liquid injection method. The use of the autosampler for the SPME fiber can facilitate the adoption of consecutive extractions; thus, it allows estimation of the partition coefficients of various analytes. Recently, GC/MS has increasingly been used in analytical laboratories; this may facilitate the identification of an unknown analyte as well as the computation of the corresponding partition coefficients with the proposed method. It is very important to use partition coefficients of organic pollutants to predict their fate in the environment. A liquid-liquid extraction technique was used to determine the partition coefficients of organic compounds between water and organic solvent. The concentration of the target compounds must be determined after equilibrium is established between the two phases. The partition coefficients can be estimated using the capacity factors of HPLC and GC

  6. Ergo betters estimates after shaky first years. [Recovery of gold, uranium and sulphuric acid

    Energy Technology Data Exchange (ETDEWEB)

    1982-05-20

    Having completed its fourth year of full operation, East Rand Gold and Uranium (ERGO) has established itself as a succesful low-cost gold producer. The recovering of gold, uranium and sulphuric acid from some old slimes dams has beaten its production estimates for 1981 till the end of March 1982. Overall Ergo has settled down well from its first years of production.

  7. Estimation of ultratrace level of uranium in sea water by laser fluorimeter

    International Nuclear Information System (INIS)

    Sahoo, S.K.; Tripathi, R.M.; Mohapatra, S.; Patra, A.C.; Lenka, P.; Puranik, V.D.

    2010-01-01

    Full text: Uranium, a naturally occurring primordial radionuclide, is imperative in the present Indian Nuclear Power Programme. Seawater may be an alternate source of uranium to meet the future demand. The total estimated quantity of uranium in seawater is around four and a half billion tonnes. Estimation of uranium in sea water is cumbersome and tedious because of ultra-trace concentration of uranium with high salt content and other interfering elements of sea water. Mainly chloride interferes in sea water analysis for estimation of nanogram level uranium because the ion at high concentration in sea water depresses uranyl complex fluorescence. At 500 ppm of chloride, the fluorescence response from a given uranium level is reduced by nearly 50%. Dilution method may be used in order to minimize the interference effect but it can't be implemented in this case as sea water contains 19000 ppm chloride but only 2-3 ppb of uranium. Thus, the separation of the interfering elements is necessary to analyze nanogram level of uranium in sea water. In the present study, an attempt has been made to analyze uranium in sea water by laser fluorimeter. Sample was treated with potassium persulphate to remove chloride ion and subsequent measurement was carried out after pH adjustment. The method was used for analysis of uranium content in 23 seawater samples ranged from 0.2 ± 0.1 μg/l to 2.2 ± 0.4 μg/l with a mean value of 1.01 ± 0.11 μg/l

  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)

    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

  11. Improvements to the quality of the estimates of US uranium reserves

    International Nuclear Information System (INIS)

    Nikodem, Z.D.

    1998-01-01

    Extensive work has been done in the United States in the estimation of uranium reserves. The government's role in uranium raw materials shifted from support of military programmes to assessing the supply available for commercial power generation. A comprehensive system evolved in which government staff estimated reserves for each property over a range of cost levels using standardized estimation methodology and criteria. The programme was assigned to the Energy Information Administration (EIA) of the Department of Energy in 1983 which has the responsibility for reporting on energy resources. As uranium supply had increased and demand had decreased, there was less concern about the adequacy of resources. In this situation, and with reduced staffing levels, the EIA adopted a two part interim approach to preparing reserve estimates. One used questionnaires to obtain uranium company estimates of their economic and subeconomic reserves, with company determined economic criteria. A second approach modified the earlier detailed government property estimates to account for production. The EIA developed a new system with the assistance of consultants and the uranium industry. The goal of the new system is to produce one set of estimates at various cost categories for each property based on a rigorous adherence to EIA criteria. Initial information is gathered from the industry through a revised annual questionnaire. Company estimates that conform to EIA standards are incorporated into the EIA reserve data base. Additional information is gathered for those estimates requiring clarification, primarily through detailed technical conferences with company staff. The EIA has the capability to prepare independent reserve estimates from basic drill hole data when required. Uranium reserves estimated for 1990 by the EIA include the initial results from the new methodology. The cooperation and support of the uranium industry have been excellent. Detailed evaluation of properties is

  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. Analysis of data on radon monitoring and dose estimates for uranium mines

    International Nuclear Information System (INIS)

    Khan, A.H.; Srivastava, G.K.; Jha, Shankar; Sagar, D.V.

    1994-01-01

    Radon progeny are the major contributors to the radiation dose to uranium miners. Monitoring for radon and gamma radiation is an integral part of radiation protection in such mines. Data for equilibrium equivalent radon and the estimated mean annual doses are presented in this paper for Jaduguda uranium mine from 1986 to 1992. The 1992 data for Jaduguda and Bhatin mines are compared. The average annual effective dose for uranium miners is estimated at around 15.5 mSv. (author). 1 ref., 2 figs

  14. Uranium estimation in toothpastes and fruit juices using solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Singh, S.; Virk, H.S.

    1984-01-01

    A fission track analysis has been used to estimate the uranium concentration in some toothpastes manufactured in India and fruit juices derived from the fruits available in the local market of Amritsar. The uranium content in these toothpastes has been found to vary from 0.91 to 3.56 ppm. The uranium content in fruit juices has been found to vary from 0.25 to 1.69 ppb. The present investigations have been carried out with an aim to estimate the level of U content in these materials for the studies of radiation health hazards. (author)

  15. 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

  16. Equal Graph Partitioning on Estimated Infection Network as an Effective Epidemic Mitigation Measure

    Science.gov (United States)

    Hadidjojo, Jeremy; Cheong, Siew Ann

    2011-01-01

    Controlling severe outbreaks remains the most important problem in infectious disease area. With time, this problem will only become more severe as population density in urban centers grows. Social interactions play a very important role in determining how infectious diseases spread, and organization of people along social lines gives rise to non-spatial networks in which the infections spread. Infection networks are different for diseases with different transmission modes, but are likely to be identical or highly similar for diseases that spread the same way. Hence, infection networks estimated from common infections can be useful to contain epidemics of a more severe disease with the same transmission mode. Here we present a proof-of-concept study demonstrating the effectiveness of epidemic mitigation based on such estimated infection networks. We first generate artificial social networks of different sizes and average degrees, but with roughly the same clustering characteristic. We then start SIR epidemics on these networks, censor the simulated incidences, and use them to reconstruct the infection network. We then efficiently fragment the estimated network by removing the smallest number of nodes identified by a graph partitioning algorithm. Finally, we demonstrate the effectiveness of this targeted strategy, by comparing it against traditional untargeted strategies, in slowing down and reducing the size of advancing epidemics. PMID:21799777

  17. Uranium mass and neutron multiplication factor estimates from time-correlation coincidence counts

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Wenxiong [China Academy of Engineering Physics, Center for Strategic Studies, Beijing 100088 (China); Li, Jiansheng [China Academy of Engineering Physics, Institute of Nuclear Physics and Chemistry, Mianyang 621900 (China); Zhu, Jianyu [China Academy of Engineering Physics, Center for Strategic Studies, Beijing 100088 (China)

    2015-10-11

    Time-correlation coincidence counts of neutrons are an important means to measure attributes of nuclear material. The main deficiency in the analysis is that an attribute of an unknown component can only be assessed by comparing it with similar known components. There is a lack of a universal method of measurement suitable for the different attributes of the components. This paper presents a new method that uses universal relations to estimate the mass and neutron multiplication factor of any uranium component with known enrichment. Based on numerical simulations and analyses of 64 highly enriched uranium components with different thicknesses and average radii, the relations between mass, multiplication and coincidence spectral features have been obtained by linear regression analysis. To examine the validity of the method in estimating the mass of uranium components with different sizes, shapes, enrichment, and shielding, the features of time-correlation coincidence-count spectra for other objects with similar attributes are simulated. Most of the masses and multiplications for these objects could also be derived by the formulation. Experimental measurements of highly enriched uranium castings have also been used to verify the formulation. The results show that for a well-designed time-dependent coincidence-count measuring system of a uranium attribute, there are a set of relations dependent on the uranium enrichment by which the mass and multiplication of the measured uranium components of any shape and size can be estimated from the features of the source-detector coincidence-count spectrum.

  18. Laser fluorimetric analysis of uranium in water from Vishakhapatnam and estimation of health risk

    International Nuclear Information System (INIS)

    Bhangare, R.C.; Tiwari, M.; Ajmal, P.Y.; Sahu, S.K.; Pandit, G.G.

    2013-01-01

    Uranium is a naturally occurring radioactive element that is both radiologically and chemically toxic. The presence of uranium in the aquatic environment is due to the leaching from natural deposits, release in mill tailings, the combustion of coal and other fuels, and the use of phosphate fertilizers that contain uranium. Intake of uranium through air and water is normally low, but in circumstances in which uranium is present in a drinking water source, the majority of intake can be through drinking water route. The uranium concentrations in ground water samples from Vishakhapatnam, India were estimated using laser fluorimetric technique and were observed to range from 0.6 to 12.3 ppb. The laser fluorimetry technique was found to be an excellent tool for direct measurement of uranium concentration in water samples at ultra-trace levels. The annual effective dose, cumulative dose for 70 years and the lifetime excess cancer risk from drinking of this water were calculated. The risks were low averaging only 10.6 x 10 -6 as none of the samples were observed to exceed the WHO recommended uranium concentration limit of 30 ppb. (author)

  19. Evapotranspiration estimation using a parameter-parsimonious energy partition model over Amazon basin

    Science.gov (United States)

    Xu, D.; Agee, E.; Wang, J.; Ivanov, V. Y.

    2017-12-01

    The increased frequency and severity of droughts in the Amazon region have emphasized the potential vulnerability of the rainforests to heat and drought-induced stresses, highlighting the need to reduce the uncertainty in estimates of regional evapotranspiration (ET) and quantify resilience of the forest. Ground-based observations for estimating ET are resource intensive, making methods based on remotely sensed observations an attractive alternative. Several methodologies have been developed to estimate ET from satellite data, but challenges remained in model parameterization and satellite limited coverage reducing their utility for monitoring biodiverse regions. In this work, we apply a novel surface energy partition method (Maximum Entropy Production; MEP) based on Bayesian probability theory and nonequilibrium thermodynamics to derive ET time series using satellite data for Amazon basin. For a large, sparsely monitored region such as the Amazon, this approach has the advantage methods of only using single level measurements of net radiation, temperature, and specific humidity data. Furthermore, it is not sensitive to the uncertainty of the input data and model parameters. In this first application of MEP theory for a tropical forest biome, we assess its performance at various spatiotemporal scales against a diverse field data sets. Specifically, the objective of this work is to test this method using eddy flux data for several locations across the Amazonia at sub-daily, monthly, and annual scales and compare the new estimates with those using traditional methods. Analyses of the derived ET time series will contribute to reducing the current knowledge gap surrounding the much debated response of the Amazon Basin region to droughts and offer a template for monitoring the long-term changes in global hydrologic cycle due to anthropogenic and natural causes.

  20. Estimation of octanol/water partition coefficient and aqueous solubility of environmental chemicals using molecular fingerprints and machine learning methods

    Science.gov (United States)

    Octanol/water partition coefficient (logP) and aqueous solubility (logS) are two important parameters in pharmacology and toxicology studies, and experimental measurements are usually time-consuming and expensive. In the present research, novel methods are presented for the estim...

  1. Uranium, thorium and REE partitioning into sulfide liquids at high pressure and high temperature: Implications for reduced, S-rich planetary bodies

    Science.gov (United States)

    Wohlers, A.; Wood, B. J.

    2017-12-01

    Based on models of the young solar nebula it is likely that the inner planets went through an early reduced phase of accretion with high metal/silicate ratio and low volatile element contents. Mercury is an existing example of a large planetary embryo with these characteristics but also with a very high S content. In order to investigate the geochemical evolution of Mercury-like bodies we experimentally determined the partitioning of lithophile elements (U, Th, Eu, Sm, Nd, Zr, La, Ce, Yb) between sulfide liquid, low-S metals and silicate melt at 1.5 GPa and 1400-2100˚C. Our results, when combined with those of Wohlers and Wood (2015) show that under highly reducing conditions (FeOsilicatemetal and FeO contents of the silicate may be understood in terms of exchange reactions: UO2 + 2FeS = 2FeO + US2silicate sulfide silicate sulfideHigh concentrations of FeSmetal and low FeO contents of the silicate melts drive the reaction to the right, yielding high US2 in the sulfide and high DU. A second effect which raises DU (and other lithophile D's) is the S content of the silicate melt. The latter increases rapidly at low FeO contents and reaches 11wt %. This greatly reduces the activity coefficient of FeO, displacing the reaction further to the right. At 1.5GPa and 1400˚C we obtain sulfide-silicate partitioning with DNd/DSm 1.4 and DTh 0.1DU. As temperature increases to 2100˚C, DNd/DSm declines to 1.0 and DTh/DU increases to 0.3. We estimated the effects of accreting a reduced sulfur-rich component (with FeS core) added to early Earth. The results at 1400˚C imply the possibility of a significant ( 11ppm) 142Nd anomaly in silicate Earth and the addition of >8 ppb U to the core, but require an unreasonably high Th/U of silicate Earth (4.54). Results at 2100˚C lead to a 142Nd anomaly of 0 but addition of such a reduced sulfur-rich body could add up to 10 ppb of U to the core, together with 21 ppb Th. This combination would generate 3 TW of the energy required for the

  2. 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)

  3. Geostatistics applied to estimation of uranium bearing ore reserves

    International Nuclear Information System (INIS)

    Urbina Galan, L.I.

    1982-01-01

    A computer assisted method for assessing uranium-bearing ore deposit reserves is analyzed. Determinations of quality-thickness, namely quality by thickness calculations of mineralization, were obtained by means of a mathematical method known as the theory of rational variables for each drill-hole layer. Geostatistical results were derived based on a Fortrand computer program on a DEC 20/40 system. (author)

  4. Systems and economics for the estimation of uranium potential supply

    International Nuclear Information System (INIS)

    Harris, D.P.; Ortiz-Vertiz, R.; Chavex, M.L.; Agbolosoo, E.K.

    1981-07-01

    This report consists of four parts, each one reasonably complete unto itself: Part I - Potential Supply Systems Based upon the Simulation of Sequential Exploration and Economic Decisions -- Systems Designed for the Analysis of NURE Endowment; Part II - Crustal Abundance and a Potential Supply System; Part III - An Investigation of Productivity and Technical Change in Exploration for and Production of Uranium; and Part IV - The Use of Solute Transport Models to Generate Geochemical Responses from a Hypothetical Uranium Deposit - An Early Effort in the Exploration Model Design. The bulk of this research was devoted to the design of potential supply systems. However, in that such systems require the modeling of exploration and exploitation, both of these activities were investigated as economic phenomena and as the subjects of models. Part I represents the largest of the research efforts. An attempt was made to design a system in which exploration is modeled in terms of both its efficiency and economics. While the exploration model demonstrated in this report is for roll-type sandstone deposits, this potential supply system, as a system per se, also applies to tabular deposits (San Juan Basin). Part II explores the concept of crustal abundance and existing crustal abundance models. The design of this crustal abundance potential supply system differs from that of any previously constructedcrustal abundance models in that it explicitly considers the third dimension, depth to deposit, and it places great emphasis upon the credible representation of the economics of exploration and exploitation. Part III reports on an attempt to measure the magnitude of technical change and depletion on the productivity of exploration and mining. This research examined these issues from the perspective of the economist, not the engineer. Part IV reports on an investigation of the feasibility of modeling the geochemical exploration for uranium, radon, and helium plumes

  5. Estimates of health risks associated with uranium transportation by air

    International Nuclear Information System (INIS)

    Elert, M.; Skagius, K.; Ericsson, A.M.; Karlsson, L.G.; Markstroem, A.

    1989-01-01

    There is today an increased interest for air transport of large quantities of uranium compounds. In this report the health risks from an aircrash where uraniumhexafluoride, uraniumdioxide powder, low enriched unirradiated fuel used in Swedish power reactors and unirradiated MTR-fuel used in the research reactor in Studsvik, is analysed. The radiation doses to personnel and the general public is calculated as well as the ground contamination from the spreaded material. Also air concentration of hydrogenflouride, from uraniumhexaflouride reacting with moisture in the air, is calculated. A number of intermediate results are presented. (authors) (69 refs.)

  6. 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.

  7. Development of flow injection analysis technique for uranium estimation

    International Nuclear Information System (INIS)

    Paranjape, A.H.; Pandit, S.S.; Shinde, S.S.; Ramanujam, A.; Dhumwad, R.K.

    1991-01-01

    Flow injection analysis is increasingly used as a process control analytical technique in many industries. It involves injection of the sample at a constant rate into a steady flowing stream of reagent and passing this mixture through a suitable detector. This paper describes the development of such a system for the analysis of uranium (VI) and (IV) and its gross gamma activity. It is amenable for on-line or automated off-line monitoring of uranium and its activity in process streams. The sample injection port is suitable for automated injection of radioactive samples. The performance of the system has been tested for the colorimetric response of U(VI) samples at 410 nm in the range of 35 to 360mg/ml in nitric acid medium using Metrohm 662 Photometer and a recorder as detector assembly. The precision of the method is found to be better than +/- 0.5%. This technique with certain modifications is used for the analysis of U(VI) in the range 0.1-3mg/ailq. by alcoholic thiocynate procedure within +/- 1.5% precision. Similarly the precision for the determination of U(IV) in the range 15-120 mg at 650 nm is found to be better than 5%. With NaI well-type detector in the flow line, the gross gamma counting of the solution under flow is found to be within a precision of +/- 5%. (author). 4 refs., 2 figs., 1 tab

  8. 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.

  9. Nonlinear estimation of weathering rate parameters for uranium in surface soil near a nuclear facility

    International Nuclear Information System (INIS)

    Killough, G.G.; Rope, S.K.; Shleien, B.; Voilleque, P.G.

    1999-01-01

    A dynamic mass-balance model has been calibrated by a nonlinear parameter estimation method, using time-series measurements of uranium in surface soil near the former Feed Materials Production Center (FMPC) near Fernald, Ohio, USA. The time-series data, taken at six locations near the site boundary since 1971, show a statistically significant downtrend of above-background uranium concentration in surface soil for all six locations. The dynamic model is based on first-order kinetics in a surface-soil compartment 10 cm in depth. Median estimates of weathering rate coefficients for insoluble uranium in this soil compartment range from about 0.065-0.14 year -1 , corresponding to mean transit times of about 7-15 years, depending on the location sampled. The model, calibrated by methods similar to those discussed in this paper, has been used to simulate surface soil kinetics of uranium for a dose reconstruction study. It was also applied, along with other data, to make confirmatory estimates of airborne releases of uranium from the FMPC between 1951 and 1988. Two soil-column models (one diffusive and one advective, the latter similar to a catenary first-order kinetic box model) were calibrated to profile data taken at one of the six locations in 1976. The temporal predictions of the advective model approximate the trend of the time series data for that location. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  10. Estimation of uranium in bioassay samples of occupational workers by laser fluorimetry

    International Nuclear Information System (INIS)

    Suja, A.; Prabhu, S.P.; Sawant, P.D.; Sarkar, P.K.; Tiwari, A.K.; Sharma, R.

    2012-01-01

    A newly established uranium processing facility has been commissioned at BARC, Trombay. Monitoring of occupational workers is essential to assess intake of uranium in this facility. A group of 21 workers was selected for bioassay monitoring to assess the existing urinary excretion levels of uranium before the commencement of actual work. Bioassay samples collected from these workers were analyzed by ion-exchange technique followed by laser fluorimetry. Standard addition method was followed for estimation of uranium concentration in the samples. The minimum detectable activity by this technique is about 0.2 ng. The range of uranium observed in these samples varies from 19 to 132 ng/L. Few of these samples were also analyzed by fission track analysis technique and the results were found to be comparable to those obtained by laser fluorimetry. The urinary excretion rate observed for the individual can be regarded as a 'personal baseline' and will be treated as the existing level of uranium in urine for these workers at the facility. (author)

  11. Estimated dose to man from uranium milling via the terrestrial food-chain pathway

    Energy Technology Data Exchange (ETDEWEB)

    Rayno, D.R.

    1982-01-01

    One of the major pathways of radiological exposure to man from uranium milling operations is through the terrestrial food chain. Studies by various investigators have shown the extent of uptake and distribution of U-238, U-234, Th-230, Ra-226, Pb-210, and Po-210 in plants and animals. These long-lived natural radioisotopes, all nuclides of the uranium decay series, are found in concentrated amounts in uranium mill tailings. Data from these investigations are used to estimate the dose to man from consumption of beef and milk contaminated by the tailings. This dose estimate from this technologically enhanced source is compared with that from average normal dietary intake of these radionuclides from natural sources.

  12. Estimated dose to man from uranium milling via the terrestrial food-chain pathway

    International Nuclear Information System (INIS)

    Rayno, D.R.

    1982-01-01

    One of the major pathways of radiological exposure to man from uranium milling operations is through the terrestrial food chain. Studies by various investigators have shown the extent of uptake and distribution of U-238, U-234, Th-230, Ra-226, Pb-210, and Po-210 in plants and animals. These long-lived natural radioisotopes, all nuclides of the uranium decay series, are found in concentrated amounts in uranium mill tailings. Data from these investigations are used to estimate the dose to man from consumption of beef and milk contaminated by the tailings. This dose estimate from this technologically enhanced source is compared with that from average normal dietary intake of these radionuclides from natural sources

  13. Estimated dose to man from uranium milling via the beef/milk food-chain pathway

    Energy Technology Data Exchange (ETDEWEB)

    Rayno, D R

    1983-12-01

    One of the major pathways of radiological exposure to man from uranium milling operations is through the beef/milk food chain. Studies by various investigators have shown the extent of uptake and distribution of 238U, 234U, 230Th, 226Ra, 210Pb, and 210Po in plants and cattle. These long-lived natural radioisotopes, all nuclides of the uranium decay series, are found in concentrated amounts in uranium mill tailings. In this paper, data from these investigations are used to estimate the dose to man from consumption of beef and milk from cattle that have fed on forage contaminated with the tailings. The estimated doses from this technologically enhanced source are compared with those resulting from average dietary intake of these radionuclides from natural sources.

  14. Analytical control of reducing agents on uranium/plutonium partitioning at purex process; Controle analitico dos agentes redutores na particao uranio/plutonio no processo purex

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Izilda da Cruz de

    1995-07-01

    Spectrophotometric methods for uranium (IV), hydrazine (N{sub 2}H{sub 4}) and its decomposition product hydrazoic acid(HN{sub 3}), and hydroxylamine (NH{sub 2} OH) determinations were developed aiming their applications for the process control of CELESTE I installation at IPEN/CNEN-SP. These compounds are normally present in the U/Pu partitioning phase of the spent nuclear treatment via PUREX process. The direct spectrophotometry was used for uranium (IV) analysis in nitric acid-hydrazine solutions based on the absorption measurement at 648 nm. The azomethine compound formed by reaction of hydrazine and p-dimethylamine benzaldehyde with maximum absorption at 457 nm was the basis for the specific analytical method for hydrazine determination. The hydrazoic acid analysis was performed indirectly by its conversion into ferric azide complex with maximum absorption at 465 nm. The hydroxylamine detection was accomplished based on its selective oxidation to nitrous acid which is easily analyzed by the reaction with Griess reagent. The resulted azocompound gas a maximum absorption at 520 nm. The sensibility of 1,4x10{sup -6}M for U(IV) with 0,8% of precision, 1,6x10{sup -6}M for hydrazine with 0,8% of precision, 2,3x10{sup -6}M hydrazoic acid with 0,9% of precision and 2,5x10{sup -6}M for hydroxylamine with 0,8% of precision were achieved. The interference studies have shown that each reducing agent can be determined in the presence of each other without any interference. Uranium(VI) and plutonium have also shown no interference in these analysis. The established methods were adapted to run inside glove-boxes by using an optical fiber colorimetry and applied to process control of the CELESTE I installation. The results pointed out that the methods are reliable and safety in order to provide just-in-time information about process conditions. (author)

  15. 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

  16. A rapid method for the separation and estimation of uranium in geological materials using ion chromatography

    International Nuclear Information System (INIS)

    Prakash, Satya; Bangroo, P.N.

    2013-01-01

    Ion Chromatography is an elegant analytical technique which was primarily developed for the analysis of anionic species and over the years it has been used successfully to analyse various elements in different matrices. In this work the potential of Ion Chromatography has been used for the rapid separation and estimation of uranium in hydrogeochemical and other geological materials

  17. A New Approach on Estimation of Solubility and n-Octanol/ Water Partition Coefficient for Organohalogen Compounds

    Directory of Open Access Journals (Sweden)

    Chenzhong Cao

    2008-06-01

    Full Text Available The aqueous solubility (logW and n-octanol/water partition coefficient (logPOW are important properties for pharmacology, toxicology and medicinal chemistry. Based on an understanding of the dissolution process, the frontier orbital interaction model was suggested in the present paper to describe the solvent-solute interactions of organohalogen compounds and a general three-parameter model was proposed to predict the aqueous solubility and n-octanol/water partition coefficient for the organohalogen compounds containing nonhydrogen-binding interactions. The model has satisfactory prediction accuracy. Furthermore, every item in the model has a very explicit meaning, which should be helpful to understand the structure-solubility relationship and may be provide a new view on estimation of solubility.

  18. 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

  19. 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

  20. Typology and Geographic Geotectonic Distribution of Uranium Deposits Typologie et répartition géographique/géotectonique des gisements d'uranium

    Directory of Open Access Journals (Sweden)

    Dahlkamp F. J.

    2006-11-01

    Full Text Available In the last ten years, twenty new uranium deposits have been discovered. They provide nearly 50% of the known and reasonably assured resources. The most important deposits known in the past by size and ore grade were those found in oligomictic quartz pebble conglomerates, sandstones and, to a lesser extent, hydrothermal veins. The types found more recently, which are greater in quantity than the former ones, are of the vein type (Canada, Australia as well as of the intrusive type (Rössing, Namibia and in calcretes (Yeelirrie, Australia and acid volcanic rocks (Mexico. Several classifications have been worked out in the past (E. W. Heinrich, 1958; M. Roubault, 1958; A. Mancher, 1962. More recently new data have enabled these classifications to be extended on a worldwide basis (Ruzicka, 1971; Ziegler, 1974; Dahlkamp, 1974, 1978 or on a regional basis (McMillon for Canada, 1978; Ingram for Australia, 1974. This classification attempt takes all available useful data into consideration to define different types of uranium deposits in as comprehensive and strict a manner as possible. Pendant les dix dernières années 20 nouveaux types de gisements d'uranium ont été découverts. Ils contribuent à assurer près de 50 % des ressources connues raisonnablement assurées. Dans le passé, les gisements les plus importants par la taille et la teneur en minerai étaient ceux des conglomérats à galets de quartz monogéniques, ceux des grès et, dans une plus faible mesure, ceux des filons hydrothermaux. Les nouveaux types connus, qui dépassent les premiers par la quantité, sont classés en gisements filoniens (Canada, Australie aussi bien qu'en intrusifs (Rössing, Namibie, en calcrêtes (Yeelirie, Australie et volcaniques acides (Mexique. Plusieurs classifications furent élaborées dans le passé (E. W. Heinrich, 1958 ; M. Roubault, 1958 ; A. Mancher, 1962. Plus récemment les données recueillies ont permis de les développer sur une base mondiale

  1. Bayesian approach to estimate AUC, partition coefficient and drug targeting index for studies with serial sacrifice design.

    Science.gov (United States)

    Wang, Tianli; Baron, Kyle; Zhong, Wei; Brundage, Richard; Elmquist, William

    2014-03-01

    The current study presents a Bayesian approach to non-compartmental analysis (NCA), which provides the accurate and precise estimate of AUC 0 (∞) and any AUC 0 (∞) -based NCA parameter or derivation. In order to assess the performance of the proposed method, 1,000 simulated datasets were generated in different scenarios. A Bayesian method was used to estimate the tissue and plasma AUC 0 (∞) s and the tissue-to-plasma AUC 0 (∞) ratio. The posterior medians and the coverage of 95% credible intervals for the true parameter values were examined. The method was applied to laboratory data from a mice brain distribution study with serial sacrifice design for illustration. Bayesian NCA approach is accurate and precise in point estimation of the AUC 0 (∞) and the partition coefficient under a serial sacrifice design. It also provides a consistently good variance estimate, even considering the variability of the data and the physiological structure of the pharmacokinetic model. The application in the case study obtained a physiologically reasonable posterior distribution of AUC, with a posterior median close to the value estimated by classic Bailer-type methods. This Bayesian NCA approach for sparse data analysis provides statistical inference on the variability of AUC 0 (∞) -based parameters such as partition coefficient and drug targeting index, so that the comparison of these parameters following destructive sampling becomes statistically feasible.

  2. 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.

  3. 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

  4. Estimates of radiological risk from depleted uranium weapons in war scenarios.

    Science.gov (United States)

    Durante, Marco; Pugliese, Mariagabriella

    2002-01-01

    Several weapons used during the recent conflict in Yugoslavia contain depleted uranium, including missiles and armor-piercing incendiary rounds. Health concern is related to the use of these weapons, because of the heavy-metal toxicity and radioactivity of uranium. Although chemical toxicity is considered the more important source of health risk related to uranium, radiation exposure has been allegedly related to cancers among veterans of the Balkan conflict, and uranium munitions are a possible source of contamination in the environment. Actual measurements of radioactive contamination are needed to assess the risk. In this paper, a computer simulation is proposed to estimate radiological risk related to different exposure scenarios. Dose caused by inhalation of radioactive aerosols and ground contamination induced by Tomahawk missile impact are simulated using a Gaussian plume model (HOTSPOT code). Environmental contamination and committed dose to the population resident in contaminated areas are predicted by a food-web model (RESRAD code). Small values of committed effective dose equivalent appear to be associated with missile impacts (50-y CEDE radiological risk. These computer simulations suggest that little radiological risk is associated to the use of depleted uranium weapons.

  5. Estimating the threshold levels of uranium and fluorine for the development of pulmonitis and toxic lung edema resultant from accidents involving uranium hexafluoride release

    International Nuclear Information System (INIS)

    Gasteva, G.N.; Antipin, E.B.; Bad'in, V.I.; Molokanov, A.A.; Mordasheva, V.V.; Mirkhajdarov, A.Kh.; Sorokin, A.V.; Savinova, I.A.

    1999-01-01

    Threshold doses of uranium and fluorine for the development of pulmonitis and toxic edema of the lung with lethal outcome are estimated. The levels of UF 6 entry under emergency conditions are evaluated and bronchopulmonary disease is described in subjects involved in three accidents with UF 6 release which occurred in the seventies and eighties, as shown by records. The results deny the previous assumption on the leading role of uranium in a single exposure to uranium hexafluoride. Fluorine ion triggering the mechanism of reactions in systems which determine the disease outcome is vitally important [ru

  6. Estimating the impact of land use change on surface energy partition based on the Noah model

    Science.gov (United States)

    Chen, Shaohui; Su, Hongbo; Zhan, Jinyan

    2014-03-01

    It is well known that land use has an important impact on surface energy partition. It is important to study the evolving trend of the partition of sensible heat flux (SHF) and latent heat flux (LHF) from the net radiance (NR) with land use change in the context of regional climate changes. In this paper, we studied the response of energy partition to land use using the Noah model. First, the Noah model simulation results of SHF and LHF between 2003 and 2005 were comprehensively validated using the observation data from the Changbai Mountain Station, the Xilinhot Station, and the Yucheng Station. The study domains represent three different types of land use change: excessive deforestation, grassland degeneration aggravation, and groundwater level decline, respectively. The study period was subsequently extended from 2015 through 2034, using four projected land use maps and forcing data from Princeton (2000-2004). The simulation results show that during the land use conversions, the annual average of LHF drops by 10.7%, rises by 10.1%, and drops by 11.5% for the Changbai Mountain, Inner Mongolia, and Northern China stations, respectively while the annual average of SHF rises by 10.6%, drops by 10.1%, and drops by 11.3% for the three areas.

  7. 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.

  8. 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.

  9. Method for estimate the economic characteristics of an uranium enrichment plant by gaseous diffusion

    International Nuclear Information System (INIS)

    Berault, J.C.

    1975-01-01

    To estimate the economic characteristics of an uranium enrichment plant by gaseous diffusion is to determine the prospective price of the separative work unit to which leads the concerned technology, and to collect the data allowing to ascertain that this price remains in the area of development of the prices forecasted by the other projects. The prospective price estimated by the promoter is the synthesis of the components of the go decision and which are a potential market and a comprehensive industrially proven plant design, including the basic economic and technical data of the project. Procedures for estimating these components and their synthesis, exclusive of financing problems are reviewed [fr

  10. Breccia-pipe uranium mining in northern Arizona; estimate of resources and assessment of historical effects

    Science.gov (United States)

    Bills, Donald J.; Brown, Kristin M.; Alpine, Andrea E.; Otton, James K.; Van Gosen, Bradley S.; Hinck, Jo Ellen; Tillman, Fred D.

    2011-01-01

    About 1 million acres of Federal land in the Grand Canyon region of Arizona were temporarily withdrawn from new mining claims in July 2009 by the Secretary of the Interior because of concern that increased uranium mining could have negative impacts on the land, water, people, and wildlife. During a 2-year interval, a Federal team led by the Bureau of Land Management is evaluating the effects of withdrawing these lands for extended periods. As part of this team, the U.S. Geological Survey (USGS) conducted a series of short-term studies to examine the historical effects of breccia-pipe uranium mining in the region. The USGS studies provide estimates of uranium resources affected by the possible land withdrawal, examine the effects of previous breccia-pipe mining, summarize water-chemistry data for streams and springs, and investigate potential biological pathways of exposure to uranium and associated contaminants. This fact sheet summarizes results through December 2009 and outlines further research needs.

  11. Estimation of intermediate-grade uranium resources II. Proposed method for estimating intermediate-grade uranium resources in roll-front deposits. Final report

    International Nuclear Information System (INIS)

    Lambie, F.W.; Yee, S.N.

    1981-09-01

    The purpose of this and a previous project was to examine the feasibility of estimating intermediate grade uranium (0.01 to 0.05% U 3 O 8 ) on the basis of existing, sparsely drilled holes. All data are from the Powder River Basin in Wyoming. DOE makes preliminary estimates of endowment by calculating an Average Area of Influence (AAI) based on densely drilled areas, multiplying that by the thickness of the mineralization and then dividing by a tonnage factor. The resulting tonnage of ore is then multiplied by the average grade of the interval to obtain the estimate of U 3 O 8 tonnage. Total endowment is the sum of these values over all mineralized intervals in all wells in the area. In regions where wells are densely drilled and approximately regularly spaced this technique approaches the classical polygonal estimation technique used to estimate ore reserves and should be fairly reliable. The method is conservative because: (1) in sparsely drilled regions a large fraction of the area is not considered to contribute to endowment; (2) there is a bias created by the different distributions of point grades and mining block grades. A conservative approach may be justified for purposes of ore reserve estimation, where large investments may hinge on local forecasts. But for estimates of endowment over areas as large as 1 0 by 2 0 quadrangles, or the nation as a whole, errors in local predictions are not critical as long as they tend to cancel and a less conservative estimation approach may be justified.One candidate, developed for this study and described is called the contoured thickness technique. A comparison of estimates based on the contoured thickness approach with DOE calculations for five areas of Wyoming roll-fronts in the Powder River Basin is presented. The sensitivity of the technique to well density is examined and the question of predicting intermediate grade endowment from data on higher grades is discussed

  12. The use of double laser pulses for the atomic-emission spectral estimation of uranium content in biological samples

    International Nuclear Information System (INIS)

    Patapovich, M.P.; Umreiko, D.S.; Zajogin, A.P.; Buloichik, J.I.

    2012-01-01

    This paper is aimed at the development of the techniques for estimation of the uranium content in biological objects (hair) using the atomic-emission laser analysis with a sufficient accuracy and high processing rate. (authors)

  13. Estimation of uranium isotope in urine samples using extraction chromatography resin

    International Nuclear Information System (INIS)

    Thakur, Smita S.; Yadav, J.R.; Rao, D.D.

    2012-01-01

    Internal exposure monitoring for alpha emitting radionuclides is carried out by bioassay samples analysis. For occupational radiation workers handling uranium in reprocessing or fuel fabrication facilities, there exists a possibility of internal exposure and urine assay is the preferred method for monitoring such exposure. Estimation of lower concentration of uranium at mBq level by alpha spectrometry requires preconcentration and its separation from large volume of urine sample. For this purpose, urine samples collected from non radiation workers were spiked with 232 U tracer at mBq level to estimate the chemical yield. Uranium in urine sample was pre-concentrated by calcium phosphate coprecipitation and separated by extraction chromatography resin U/TEVA. In this resin extractant was DAAP (Diamylamylphosphonate) supported on inert Amberlite XAD-7 support material. After co-precipitation, precipitate was centrifuged and dissolved in 10 ml of 1M Al(NO 3 ) 3 prepared in 3M HNO 3 . The sample thus prepared was loaded on extraction chromatography resin, pre-conditioned with 10 ml of 3M HNO 3 . Column was washed with 10 ml of 3M HNO 3 . Column was again rinsed with 5 ml of 9M HCl followed by 20 ml of 0.05 M oxalic acid prepared in 5M HCl to remove interference due to Th and Np if present in the sample. Uranium was eluted from U/TEVA column with 15 ml of 0.01M HCl. The eluted uranium fraction was electrodeposited on stainless steel planchet and counted by alpha spectrometry for 360000 sec. Approximate analysis time involved from sample loading to stripping is 2 hours when compared with the time involved of 3.5 hours by conventional ion exchange method. Seven urine samples from non radiation worker were radio chemically analyzed by this technique and the radiochemical yield was found in the range of 69-91 %. Efficacy of this method against conventional anion exchange technique earlier standardized at this laboratory is also being highlighted. Minimum detectable activity

  14. Estimation of the soil-water partition coefficient normalized to organic carbon for ionizable organic chemicals

    DEFF Research Database (Denmark)

    Franco, Antonio; Trapp, Stefan

    2008-01-01

    The sorption of organic electrolytes to soil was investigated. A dataset consisting of 164 electrolytes, composed of 93 acids, 65 bases, and six amphoters, was collected from literature and databases. The partition coefficient log KOW of the neutral molecule and the dissociation constant pKa were...... calculated by the software ACD/Labs®. The Henderson-Hasselbalch equation was applied to calculate dissociation. Regressions were developed to predict separately for the neutral and the ionic molecule species the distribution coefficient (Kd) normalized to organic carbon (KOC) from log KOW and pKa. The log...... KOC of strong acids (pKa correlated to these parameters. The regressions derived for weak acids and bases (undissociated at environmental pH) were similar. The highest sorption was found for strong bases (pKa > 7.5), probably due to electrical interactions. Nonetheless, their log KOC...

  15. 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)

  16. A rapid method to estimate uranium using ionic liquid as extracting agent from basic aqueous media

    International Nuclear Information System (INIS)

    Prabhath Ravi, K.; Sathyapriya, R.S.; Rao, D.D.; Ghosh, S.K.

    2016-01-01

    Room temperature ionic liquids, as their name suggests are salts with a low melting point typically less than 100 °C and exist as liquid at room temperature. The common cationic parts of ionic liquids are imidazolium, pyridinium, pyrrolidinium, quaternary ammonium, or phosphonium ions, and common anionic parts are chloride, bromide, boron tetrafluorate, phosphorous hexafluorate, triflimide etc. The physical properties of ionic liquids can be tuned by choosing appropriate cations with differing alkyl chain lengths and anions. Application of ionic liquids in organic synthesis, liquid-liquid extractions, electrochemistry, catalysis, speciation studies, nuclear reprocessing is being studied extensively in recent times. In this paper a rapid method to estimate the uranium content in aqueous media by extraction with room temperature ionic liquid tricaprylammoniumthiosalicylate ((A- 336)(TS)) followed by liquid scintillation analysis is described. Re-extraction of uranium from ionic liquid phase to aqueous phase was also studied

  17. Methods for the estimation and economic evaluation of undiscovered uranium endowment and resources

    International Nuclear Information System (INIS)

    1992-01-01

    The present Instruction Manual was prepared as part of a programme of the International Atomic Energy Agency to supply the international uranium community with standard guides for a number of topics related to uranium resource assessment and supply. The quantitative estimation of undiscovered resources and endowments aims at supplying data on potential mineral resources; these data are needed to compare long term projections with one another and to assess the mineral supplies to be obtained from elsewhere. These objectives have relatively recently been supplemented by the concern of land managers and national policy planners to assess the potential of certain lands before the constitution of national parks and other areas reserved from mineral exploration and development. 88 refs, 28 figs, 33 tabs

  18. Estimates of health risks associated with uranium hexafluoride transport by air

    International Nuclear Information System (INIS)

    Elert, M.; Skagius, K.

    1990-01-01

    In Sweden air transport is considered as an alternative for the shipment of uranium hexafluoride (UF 6 ). The radiological consequences of an aeroplane accident involving UF 6 transport have been estimated and are presented as the dose from acute exposure and the dose from long-term exposure caused by ground contamination. Chemical effects of a UF 6 release are also discussed. A number of limiting scenarios have been defined, resulting in different mechanical and thermal impacts on the transport packages. The expected accident environment and the physical and chemical behaviour of the material have been used to derive a source term for the release to the air. A Gaussian dispersion model has been used to calculate the expected air concentration downwind from the accident site. The radiation dose from short-term exposure was found to be higher than the long-term exposure from uranium deposited on the ground. (author)

  19. Comparison of modeling approaches for carbon partitioning: Impact on estimates of global net primary production and equilibrium biomass of woody vegetation from MODIS GPP

    Science.gov (United States)

    Ise, Takeshi; Litton, Creighton M.; Giardina, Christian P.; Ito, Akihiko

    2010-12-01

    Partitioning of gross primary production (GPP) to aboveground versus belowground, to growth versus respiration, and to short versus long-lived tissues exerts a strong influence on ecosystem structure and function, with potentially large implications for the global carbon budget. A recent meta-analysis of forest ecosystems suggests that carbon partitioning to leaves, stems, and roots varies consistently with GPP and that the ratio of net primary production (NPP) to GPP is conservative across environmental gradients. To examine influences of carbon partitioning schemes employed by global ecosystem models, we used this meta-analysis-based model and a satellite-based (MODIS) terrestrial GPP data set to estimate global woody NPP and equilibrium biomass, and then compared it to two process-based ecosystem models (Biome-BGC and VISIT) using the same GPP data set. We hypothesized that different carbon partitioning schemes would result in large differences in global estimates of woody NPP and equilibrium biomass. Woody NPP estimated by Biome-BGC and VISIT was 25% and 29% higher than the meta-analysis-based model for boreal forests, with smaller differences in temperate and tropics. Global equilibrium woody biomass, calculated from model-specific NPP estimates and a single set of tissue turnover rates, was 48 and 226 Pg C higher for Biome-BGC and VISIT compared to the meta-analysis-based model, reflecting differences in carbon partitioning to structural versus metabolically active tissues. In summary, we found that different carbon partitioning schemes resulted in large variations in estimates of global woody carbon flux and storage, indicating that stand-level controls on carbon partitioning are not yet accurately represented in ecosystem models.

  20. 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

  1. Estimating long-term uranium resource availability and discovery requirements. A Canadian case study

    International Nuclear Information System (INIS)

    Martin, H.L.; Azis, A.; Williams, R.M.

    1979-01-01

    Well-founded estimates of the rate at which a country's resources might be made available are a prime requisite for energy planners and policy makers at the national level. To meet this need, a method is discussed that can aid in the analysis of future supply patterns of uranium and other metals. Known sources are first appraised, on a mine-by-mine basis, in relation to projected domestic needs and expectable export levels. The gap between (a) production from current and anticipated mines, and (b) production levels needed to meet both domestic needs and export opportunities, would have to be met by new sources. Using as measuring sticks the resources and production capabilities of typical uranium deposits, a measure can be obtained of the required timing and magnitude of discovery needs. The new discoveries, when developed into mines, would need to be sufficient to meet not only any shortfalls in production capability, but also any special reserve requirements as stipulated, for example, under Canada's uranium export guidelines. Since the method can be followed simply and quickly, it can serve as a valuable tool for long-term supply assessments of any mineral commodity from a nation's mines. (author)

  2. 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.

  3. Radiation dose estimates from a mining plan for a high-grade uranium deposit

    International Nuclear Information System (INIS)

    Scott, L.M.

    1981-01-01

    The significance of gamma exposure to uranium miners has been recognized only in the last few years. Most ore deposits which have been underground mined, were 1% or less U 3 O 8 . Full-time mining of this grade ore can result in exposure exceeding 1 Rem per year. Several companies in Saskatchewan are planning to mine recently discovered ore bodies which contain ore pods in excess of 10% U 3 O 8 . The purpose of this paper is to present dose data which can be used to estimate gamma exposure from high-grade ore deposits, and to present mining techniques which will minimize miner exposure

  4. On a Bayesian estimation procedure for determining the average ore grade of a uranium deposit

    International Nuclear Information System (INIS)

    Heising, C.D.; Zamora-Reyes, J.A.

    1996-01-01

    A Bayesian procedure is applied to estimate the average ore grade of a specific uranium deposit (the Morrison formation in New Mexico). Experimental data taken from drilling tests for this formation constitute deposit specific information, E 2 . This information is combined, through a single stage application of Bayes' theorem, with the more extensive and well established information on all similar formations in the region, E 1 . It is assumed that the best estimate for the deposit specific case should include the relevant experimental evidence collected from other like formations giving incomplete information on the specific deposit. This follows traditional methods for resource estimation, which presume that previous collective experience obtained from similar formations in the geological region can be used to infer the geologic characteristics of a less well characterized formation. (Author)

  5. Contribution to the methods for estimating uranium deposits (1963); Contribution aux methodes d'estimation des gisements d'uranium (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Carlier, A. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-02-15

    Having defined a deposit of economic value according to the marginal theory, the author discriminates several categories of ore reserves according to the degree of knowledge of the deposit and according to the mining stage where the ore is considered. He dismisses the conventional French classification of 'on sight', 'probable' and 'possible' ore categories and suggests more suitable ones. The 'sensu stricto', ore reserves are those for which the random error can be calculated. The notion of the natural contrast of grades in an ore deposit (absolute dispersion coefficient {alpha}) is introduced in relation to this topic. The author considers three types of mining exploration. The first is the random exploration so often met; the second is the logical exploration based on a systematic location of underground works, bore-holes, etc. The third, and hardest to achieve, is the one which minimizes exploration costs for a given level of accuracy. Part of the publication deals with sampling errors such as those resulting from the quartering of a heap of ore (theory of Pierre GY) or those resulting from the use of radiometric measurement of grade. Another part deals with the extension error (entailed by the assimilation of samples to the deposit they are issued from) and gives the essential formulae in order to appraise the random error (Geo-statistics of Matheron). As to the estimator itself the work shows how the disharmony between the ore sample and the associated influence zone can be solved by the way of 'kriging'. The thesis gives numerous examples of the various numerical parameters, characteristics of an uranium deposit (absolute dispersion coefficient) or of an uranium ore (liberation parameter) as well as a few examples of linear correlations between gamma radioactivity and uranium grade. Three complete examples of reserve evaluation are given. The end of the thesis deals with the notion of ruin risk which has to

  6. Contribution to the methods for estimating uranium deposits (1963); Contribution aux methodes d'estimation des gisements d'uranium (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Carlier, A [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-02-15

    Having defined a deposit of economic value according to the marginal theory, the author discriminates several categories of ore reserves according to the degree of knowledge of the deposit and according to the mining stage where the ore is considered. He dismisses the conventional French classification of 'on sight', 'probable' and 'possible' ore categories and suggests more suitable ones. The 'sensu stricto', ore reserves are those for which the random error can be calculated. The notion of the natural contrast of grades in an ore deposit (absolute dispersion coefficient {alpha}) is introduced in relation to this topic. The author considers three types of mining exploration. The first is the random exploration so often met; the second is the logical exploration based on a systematic location of underground works, bore-holes, etc. The third, and hardest to achieve, is the one which minimizes exploration costs for a given level of accuracy. Part of the publication deals with sampling errors such as those resulting from the quartering of a heap of ore (theory of Pierre GY) or those resulting from the use of radiometric measurement of grade. Another part deals with the extension error (entailed by the assimilation of samples to the deposit they are issued from) and gives the essential formulae in order to appraise the random error (Geo-statistics of Matheron). As to the estimator itself the work shows how the disharmony between the ore sample and the associated influence zone can be solved by the way of 'kriging'. The thesis gives numerous examples of the various numerical parameters, characteristics of an uranium deposit (absolute dispersion coefficient) or of an uranium ore (liberation parameter) as well as a few examples of linear correlations between gamma radioactivity and uranium grade. Three complete examples of reserve evaluation are given. The end of the thesis deals with the notion of ruin risk which has to be taken in some cases. A detailed alphabetical

  7. Application of covariance clouds for estimating the anisotropy ellipsoid eigenvectors, with case study in uranium deposit

    International Nuclear Information System (INIS)

    Jamali Esfahlan, D.; Madani, H.; Tahmaseb Nazemi, M. T.; Mahdavi, F.; Ghaderi, M. R.; Najafi, M.

    2010-01-01

    Various methods of Kriging and nonlinear geostatistical methods considered as acceptable methods for resource and reserve estimations have characters such as the least estimation variance in their nature, and accurate results in the acceptable confidence levels range could be achieved if the required parameters for the estimation are determined accurately. If the determined parameters don't have the sufficient accuracy, 3-D geostatistical estimations will not be reliable any more, and by this, all the quantitative parameters of the mineral deposit (e.g. grade-tonnage variations) will be misinterpreted. One of the most significant parameters for 3-D geostatistical estimation is the anisotropy ellipsoid. The anisotropy ellipsoid is important for geostatistical estimations because it determines the samples in different directions required for accomplishing the estimation. The aim of this paper is to illustrate a more simple and time preserving analytical method that can apply geophysical or geochemical analysis data from the core-length of boreholes for modeling the anisotropy ellipsoid. By this method which is based on the distribution of covariance clouds in a 3-D sampling space of a deposit, quantities, ratios, azimuth and plunge of the major-axis, semi-major axis and the minor-axis determine the ore-grade continuity within the deposit and finally the anisotropy ellipsoid of the deposit will be constructed. A case study of an uranium deposit is also analytically discussed for illustrating the application of this method.

  8. Estimates of future demand for uranium and nuclear fuel cycle services

    Energy Technology Data Exchange (ETDEWEB)

    Krymm, R; Woite, G [International Atomic Energy Agency, Division of Nuclear Power and Reactors, Economic Studies Section, Vienna (Austria)

    1976-07-01

    As a review of forecasts made over the last few years amply demonstrates, projections of nuclear power capacity on a country, regional or world basis are subject to uncertainties. It summarizes the evolution of estimates made in the recent past, should provide a sobering reminder of the advisability of relying on ranges rather than on single figures. Although they are derived from a relatively narrow range of assumptions for nuclear power capacity, the alternative estimates of demands for uranium and nuclear-fuel-cycle services differ by about 50%. If plausible variations in breeder penetration, load factors, tails assays and fuel performance were taken into account, a ratio of 2 between maximum and minimum possible demands for the 2000 could easily be approached. Thus, for instance, a 15% (instead of 5%) breeder penetration by the year 2000 would decrease annual natural uranium demand by about 10%, a drop of load factor from 0.7 to 0.6 would drop the demand by another 10%, a decrease in tail assay from 0.25% to 0.2% would drop the demand by 8%. These momentous uncertainties, characteristic of medium- and long-term demand projections, offer a sharp contrast to the inflexibility of short-term requirements. Once a nuclear plant is ordered, the demand for the fuel services required for its core and for its replacement loadings is practically fixed (subject to minor trade-offs) and it can only be delayed in time by accepting exceedingly heavy additional costs. The demand for uranium can be characterized as being uncertain in the future and inelastic in the present. It faces sources of supply which, with the exception of fabrication and conversion facilities, are characterized by long planning times, lengthy prospecting and construction times, and above all by heavy capital investments. This combination offers an almost ideal framework for instability and wild price fluctuations if consumers and suppliers operate independently seeking temporary guidance in their

  9. Estimates of future demand for uranium and nuclear fuel cycle services

    International Nuclear Information System (INIS)

    Krymm, R.; Woite, G.

    1976-01-01

    As a review of forecasts made over the last few years amply demonstrates, projections of nuclear power capacity on a country, regional or world basis are subject to uncertainties. It summarizes the evolution of estimates made in the recent past, should provide a sobering reminder of the advisability of relying on ranges rather than on single figures. Although they are derived from a relatively narrow range of assumptions for nuclear power capacity, the alternative estimates of demands for uranium and nuclear-fuel-cycle services differ by about 50%. If plausible variations in breeder penetration, load factors, tails assays and fuel performance were taken into account, a ratio of 2 between maximum and minimum possible demands for the 2000 could easily be approached. Thus, for instance, a 15% (instead of 5%) breeder penetration by the year 2000 would decrease annual natural uranium demand by about 10%, a drop of load factor from 0.7 to 0.6 would drop the demand by another 10%, a decrease in tail assay from 0.25% to 0.2% would drop the demand by 8%. These momentous uncertainties, characteristic of medium- and long-term demand projections, offer a sharp contrast to the inflexibility of short-term requirements. Once a nuclear plant is ordered, the demand for the fuel services required for its core and for its replacement loadings is practically fixed (subject to minor trade-offs) and it can only be delayed in time by accepting exceedingly heavy additional costs. The demand for uranium can be characterized as being uncertain in the future and inelastic in the present. It faces sources of supply which, with the exception of fabrication and conversion facilities, are characterized by long planning times, lengthy prospecting and construction times, and above all by heavy capital investments. This combination offers an almost ideal framework for instability and wild price fluctuations if consumers and suppliers operate independently seeking temporary guidance in their

  10. Computational estimation of logarithm of octanol/air partition coefficients and subcooled vapour pressures for each of 75 chloronaphtalene congeners

    Energy Technology Data Exchange (ETDEWEB)

    Puzyn, T.; Falandysz, J.; Rostkowski, P.; Piliszek, S.; Wilczyniska, A. [Univ. of Gdansk (Poland)

    2004-09-15

    Polychlorinated naphthalenes (PCNs, CNs) are known persistent organic pollutants, contaminating natural ecosystems in effect of technical human activity. Toxic effects induced by individual congers of PCNs are reported elsewhere. Great risk of these chemical compounds is additionally connected with theirs excellent ability to be transported via atmosphere from a source to the remote regions on the Glob. Chloronaphthalene congeners had been found in Arctic regions at significant level in spite of the fact, that they had never been synthesized there, and also thermal processes like municipal waste incineration or domestic heating (other possible sources of PCNs in the environment) were not so intensive there. In 1996 F. Wania and D. Mackay have formulated some empirical rules, which have been very useful in estimation and modeling of environmental transport processes of persistent organic pollutants like PCNs. Two very important physico-chemical parameters in the theory of global distillation and cold condensation are: logarithm of n-octanol/air partition coefficient (log K{sub OA}) and logarithm of subcooled vapour pressure (log P{sub L}). Values of log K{sub OA} and log P{sub L} in standard procedures are determined by means of chromatographic methods. In order to reduce costs and number of experiments, we have proposed simple computational method of estimation log K{sub OA} and log P{sub L}.

  11. Landform partitioning and estimates of deep storage of soil organic matter in Zackenberg, Greenland

    Directory of Open Access Journals (Sweden)

    J. Palmtag

    2018-05-01

    Full Text Available Soils in the northern high latitudes are a key component in the global carbon cycle, with potential feedback on climate. This study aims to improve the previous soil organic carbon (SOC and total nitrogen (TN storage estimates for the Zackenberg area (NE Greenland that were based on a land cover classification (LCC approach, by using geomorphological upscaling. In addition, novel organic carbon (OC estimates for deeper alluvial and deltaic deposits (down to 300 cm depth are presented. We hypothesise that landforms will better represent the long-term slope and depositional processes that result in deep SOC burial in this type of mountain permafrost environments. The updated mean SOC storage for the 0–100 cm soil depth is 4.8 kg C m−2, which is 42 % lower than the previous estimate of 8.3 kg C m−2 based on land cover upscaling. Similarly, the mean soil TN storage in the 0–100 cm depth decreased with 44 % from 0.50 kg (± 0.1 CI to 0.28 (±0.1 CI kg TN m−2. We ascribe the differences to a previous areal overestimate of SOC- and TN-rich vegetated land cover classes. The landform-based approach more correctly constrains the depositional areas in alluvial fans and deltas with high SOC and TN storage. These are also areas of deep carbon storage with an additional 2.4 kg C m−2 in the 100–300 cm depth interval. This research emphasises the need to consider geomorphology when assessing SOC pools in mountain permafrost landscapes.

  12. Landform partitioning and estimates of deep storage of soil organic matter in Zackenberg, Greenland

    Science.gov (United States)

    Palmtag, Juri; Cable, Stefanie; Christiansen, Hanne H.; Hugelius, Gustaf; Kuhry, Peter

    2018-05-01

    Soils in the northern high latitudes are a key component in the global carbon cycle, with potential feedback on climate. This study aims to improve the previous soil organic carbon (SOC) and total nitrogen (TN) storage estimates for the Zackenberg area (NE Greenland) that were based on a land cover classification (LCC) approach, by using geomorphological upscaling. In addition, novel organic carbon (OC) estimates for deeper alluvial and deltaic deposits (down to 300 cm depth) are presented. We hypothesise that landforms will better represent the long-term slope and depositional processes that result in deep SOC burial in this type of mountain permafrost environments. The updated mean SOC storage for the 0-100 cm soil depth is 4.8 kg C m-2, which is 42 % lower than the previous estimate of 8.3 kg C m-2 based on land cover upscaling. Similarly, the mean soil TN storage in the 0-100 cm depth decreased with 44 % from 0.50 kg (± 0.1 CI) to 0.28 (±0.1 CI) kg TN m-2. We ascribe the differences to a previous areal overestimate of SOC- and TN-rich vegetated land cover classes. The landform-based approach more correctly constrains the depositional areas in alluvial fans and deltas with high SOC and TN storage. These are also areas of deep carbon storage with an additional 2.4 kg C m-2 in the 100-300 cm depth interval. This research emphasises the need to consider geomorphology when assessing SOC pools in mountain permafrost landscapes.

  13. Estimation of rare earth elements in uranium matrix after solvent extraction of uranium as uranium-antipyrine-anion complex using chloroform as solvent

    International Nuclear Information System (INIS)

    Bose, Roopa; Murthy, D.S.R.; Malhotra, R.K.

    1999-01-01

    The neutron economy in a nuclear reactor dictates the occurrence of neutron absorbers at very low levels. Hence the determination of lanthanides especially Sm, Eu, Gd and Dy is one of the most difficult and complicated analytical tasks particularly in high uranium matrix. Solvent extraction is a potent and versatile technique for the separation of lanthanides. The systems generally used for lanthanide extraction are TBP-nitrate, TBP-chloride, TBP-thiocyanate TOPO, DEHPA-nitrate etc. However, these methods of extraction of lanthanides fail to give a clear cut separation for their determination from uranium matrix. Hence analytical procedures have been standardised for extraction of uranium matrix into the organic phase leaving lanthanides unextracted in the aqueous phase. In this direction Cyanex-923 a mixture of 4 trialkyl phosphine oxides, TBP- TOPO and trioctylamine in xylene have been used for extraction of uranium and consequent determination of lanthanides by ICP-AES in the aqueous phase. In this paper the authors have investigated uranium -antipyrine -anion, a different combination other than the well known phosphine oxides and tertiary amines for extraction of uranium

  14. Health effects estimation: Methods and results for uranium mill tailings contaminated properties

    International Nuclear Information System (INIS)

    Denham, D.H.; Cross, F.T.; Soldat, J.K.

    1990-01-01

    This paper describes methods for estimating potential health effects from exposure to uranium mill tailings and presents a summary of risk projections for 50 contaminated properties (residences, schools, churches, and businesses) in the US. The methods provide realistic estimates of cancer risk to exposed individuals based on property-specific occupancy and contamination patterns. External exposure to gamma radiation, inhalation of radon daughters, and consumption of food products grown in radium-contaminated soil are considered. Most of the projected risk was from indoor exposure to radon daughters; however, for some properties the risk from consumption of locally grown food products is similar to that from radon daughters. In all cases, the projected number of lifetime cancer deaths for specific properties is less than one, but for some properties the increase in risk over that normally expected is greater than 100%

  15. Estimation of uranium and cobalt-60 distribution coefficients and uranium-235 enrichment at the Combustion Engineering Company site in Windsor, Connecticut

    International Nuclear Information System (INIS)

    Wang, Y.; Orlandini, K.A.; Yu, C.

    1996-05-01

    Site-specific distribution coefficients for uranium isotopes and cobalt-60 (Co-60) and the fraction of uranium-235 (U-235) enrichment by mass were estimated for environmental samples collected from the Combustion Engineering Company site in Windsor, CT. This site has been identified for remedial action under the US Department of Energy's (DOE) Formerly Utilized Sites Remedial Action Program. The authority of DOE at the Combustion Engineering site is limited to (1) Building 3; (2) other activities or areas associated exclusively with Building 3 (such as sewer lines); or (3) contamination that is exclusively highly enriched uranium. In this study, 16 samples were collected from the Combustion Engineering site, including 8 soil, 4 sediment, 3 water, and 1 water plus sludge sample. These samples were analyzed for isotopic uranium by alpha spectrometry and for Co-60 by gamma spectrometry. The site-specific distribution coefficient for each isotope was estimated as the ratio of extractable radionuclide activity in the solid phase to the activity in the contact solution following a 19-day equilibration. The uranium activity measurements indicate that uranium-234 (U-234) and uranium-238 (U-238) were in secular equilibrium in two soil samples and that soil and sediment samples collected from other sampling locations had higher U-234 activity than U-238 activity in both the solid and solution phases. The site-specific distribution coefficient (Kd) ranged from 82 to 44,600 mL/g for U-238 and from 102 to 65,900 mL/g for U-234. Calculation of U-235 enrichment by mass indicated that four soil samples had values greater than 0.20; these values were 0.37, 0.38, 0.46, and 0.68. Cobalt-60 activity was detected in only three sediment samples. The measured Co-60 activity in the solid phase ranged from 0.15 to 0.45 pCi/g and that in the water phase of all three samples combined was 4 pCi/L. The Kd value for Co-60 in the site brook sediment was calculated to be 70 mL/g

  16. Intermediate-term uranium supply curve estimation. Final report, February 1981

    International Nuclear Information System (INIS)

    Steyn, J.J.; Goudarzi, L.A.; Douglas, R.F.

    1981-02-01

    The study was undertaken to estimate US natural uranium supply capacities and associated economic costs over the intermediate term period, 1979 to 1990, and to develop the general supply outlook to 2000. Annual supply capacity schedules were estimated on an individual mill and mine family (production center) basis. Future production schedules were estimated by balancing estimated supply capacity with DOE future demand projections ranging from 150 GWe to 396 GWe of installed nuclear capacity in 2000; the impact of private sector inventory levels was accounted for. The long run economic cost of production was estimated by applying a specifically derived production cost model to individual mines and mills using available data, as for example, ore depths, grades, production type and capacity, mill recovery; economic assumptions, as for example, 16% return on equity, were also made. The study report presents details of the methodology and data used, and the results obtained; the production center assessment, the supply/cost curves developed, and the cost models used, are also presented. For the current trend outlook, the results indicate that existing and under-construction centers can meet the bulk of demand through 1990, and that new centers will be required to meet substantial shortfalls in the 1990s. The study indicated that the US average long run economic cost of $30 per pound in 1979, in constant dollars, will begin to increase after 1985 at between 4 and 5%

  17. Criticality accident in uranium fuel processing plant. The estimation of the total number of fissions with related reactor physics parameters

    International Nuclear Information System (INIS)

    Nishina, Kojiro; Oyamatsu, Kazuhiro; Kondo, Shunsuke; Sekimoto, Hiroshi; Ishitani, Kazuki; Yamane, Yoshihiro; Miyoshi, Yoshinori

    2000-01-01

    This accident occurred when workers were pouring a uranium solution into a precipitation tank with handy operation against the established procedure and both the cylindrical diameter and the total mass exceeded the limited values. As a result, nuclear fission chain reactor in the solution reached not only a 'criticality' state continuing it independently but also an instantly forming criticality state exceed the criticality and increasing further nuclear fission number. The place occurring the accident at this time was not reactor but a place having not to form 'criticality' called by a processing process of uranium fuel. In such place, as because of relating to mechanism of chain reaction, it is required naturally for knowledge on the reactor physics, it is also necessary to understand chemical reaction in chemical process, and functions of tanks, valves and pumps mounted at the processes. For this purpose, some information on uranium concentration ratio, atomic density of nuclides largely affecting to chain reaction such as uranium, hydrogen, and so forth in the solution, shape, inner structure and size of container for the solution, and its temperature and total volume, were necessary for determining criticality volume of the accident uranium solution by using nuclear physics procedures. Here were described on estimation of energy emission in the JCO accident, estimation from analytical results on neutron and solution, calculation of various nuclear physics property estimation on the JCO precipitation tank at JAERI. (G.K.)

  18. Estimating the octanol/water partition coefficient for aliphatic organic compounds using semi-empirical electrotopological index.

    Science.gov (United States)

    Souza, Erica Silva; Zaramello, Laize; Kuhnen, Carlos Alberto; Junkes, Berenice da Silva; Yunes, Rosendo Augusto; Heinzen, Vilma Edite Fonseca

    2011-01-01

    A new possibility for estimating the octanol/water coefficient (log P) was investigated using only one descriptor, the semi-empirical electrotopological index (I(SET)). The predictability of four octanol/water partition coefficient (log P) calculation models was compared using a set of 131 aliphatic organic compounds from five different classes. Log P values were calculated employing atomic-contribution methods, as in the Ghose/Crippen approach and its later refinement, AlogP; using fragmental methods through the ClogP method; and employing an approach considering the whole molecule using topological indices with the MlogP method. The efficiency and the applicability of the I(SET) in terms of calculating log P were demonstrated through good statistical quality (r > 0.99; s < 0.18), high internal stability and good predictive ability for an external group of compounds in the same order as the widely used models based on the fragmental method, ClogP, and the atomic contribution method, AlogP, which are among the most used methods of predicting log P.

  19. Bioavailability of Antibiotics at Soil-Water Interfaces: A Comparison of Measured Activities and Equilibrium Partitioning Estimates.

    Science.gov (United States)

    Menz, Jakob; Müller, Julia; Olsson, Oliver; Kümmerer, Klaus

    2018-06-05

    There are growing concerns that antibiotic pollution impacts environmental microbiota and facilitates the propagation of antibiotic resistance. However, the prediction or analytical determination of bioavailable concentrations of antibiotics in soil is still subject to great uncertainty. Biological assays are increasingly recognized as valuable complementary tools that allow a more direct determination of the residual antibiotic activity. This study assessed the bioavailability of structurally diverse antibiotics at a soil-water interface applying activity-based analyses in conjunction with equilibrium partitioning (EqP) modeling. The activity against Gram-positive and Gram-negative bacteria of nine antibiotics from different classes was determined in the presence and absence of standard soil (LUFA St. 2.2). The addition of soil affected the activity of different antibiotics to highly varying degrees. Moreover, a highly significant correlation ( p < 0.0001) between the experimentally observed and the EqP-derived log EC 50 (half-maximal effective concentration) values was observed. The innovative experimental design of this study provided new insights on the bioavailability of antibiotics at soil-water interfaces. EqP appears to be applicable to a broad range of antibiotics for the purpose of screening-level risk assessment. However, EqP estimates cannot replace soil-specific ecotoxicity testing in higher-tier assessments, since their accuracy is still compromised by a number of factors.

  20. Biamperometric estimation of uranium in input KMP samples of spent fuel reprocessing plant: field experience

    International Nuclear Information System (INIS)

    Gurba, P.B.; Dhakras, S.P.; Chaugule, G.A.; Venugopal, A.K.; Singh, R.K.; Bajpai, D.D.; Nair, P.R.; Xavier, Mary; Aggarwal, S.K.

    2000-01-01

    Feasibility of simple, precise and accurate biamperometric determination of uranium at about 0.1 mg level was earlier established using simulated uranium standards. To evaluate the usefulness of this method for accurate determination of uranium in spent fuel dissolver solution samples, analytical work was carried out

  1. Methods for obtaining distributions of uranium occurrence from estimates of geologic features

    International Nuclear Information System (INIS)

    Ford, C.E.; McLaren, R.A.

    1980-04-01

    The problem addressed in this paper is the determination of a quantitative estimate of a resource from estimates of fundamental variables which describe the resource. Due to uncertainty about the estimates, these basic variables are stochastic. The evaluation of random equations involving these variables is the core of the analysis process. The basic variables are originally described in terms of a low and a high percentile (the 5th and 95th, for example) and a central value (the mode, mean or median). The variable thus described is then generally assumed to be represented by a three-parameter lognormal distribution. Expressions involving these variables are evaluated by computing the first four central moments of the random functions (which are usually products and sums of variables). Stochastic independence is discussed. From the final set of moments a Pearson distribution is obtained; the high values of skewness and kurtosis resulting from uranium data require obtaining Pearson curves beyond those described in published tables. A cubic spline solution to the Pearson differential equation accomplishes this task. A sample problem is used to illustrate the application of the process; sensitivity to the estimated values of the basic variables is discussed. Appendices contain details of the methods and descriptions of computer programs

  2. Methods for obtaining distributions of uranium occurrence from estimates of geologic features

    International Nuclear Information System (INIS)

    Ford, C.E.; McLaren, R.A.

    1980-04-01

    The problem addressed in this report is the determination of a quantitative estimate of a resource from estimates of fundamental variables which describe the resource. Due to uncertainty about the estimates, these basic variables are stochastic. The evaluation of random equations involving these variables is the core of the analysis process. The basic variables are originally described in terms of a low and a high percentile (the 5th and 95th, for example) and a central value (the mode, mean or median). The variable thus described is then generally assumed to be represented by a three-parameter lognormal distribution. Expressions involving these variables are evaluated by computing the first four central moments of the random functions (which are usually products and sums of variables). Stochastic independence is discussed. From the final set of moments a Pearson distribution is obtained; the high values of skewness and kurtosis resulting from uranium data requires obtaining Pearson curves beyond those described in published tables. A cubic spline solution to the Pearson differential equation accomplishes this task. A sample problem is used to illustrate the application of the process; sensitivity to the estimated values of the basic variables is discussed. Appendices contain details of the methods and descriptions of computer programs

  3. Lifetime estimates of a fusion reactor first wall by linear damage summation and strain range partitioning methods

    International Nuclear Information System (INIS)

    Liu, K.C.; Grossbeck, M.L.

    1979-01-01

    A generalized model of a first wall made of 20% cold-worked steel was examined for neutron wall loadings ranging from 2 to 5 MW/m 2 . A spectrum of simplified on-off duty cycles was assumed with a 95% burn time. Independent evaluations of cyclic lifetimes were based on two methods: the method of linear damage summation currently being employed for use in ASME high-temperature design Code Case N-47 and that of strain range partitioning being studied for inclusion in the design code. An important point is that the latter method can incorporate a known decrease in ductility for materials subject to irradiation as a parameter, so low-cycle fatigue behavior can be estimated for irradiated material. Lifetimes predicted by the two methods agree reasonably well despite their diversity in concept. Lack of high-cycle fatigue data for the material tested at temperatures within the range of our interest precludes making conclusions on the accuracy of the predicted results, but such data are forthcoming. The analysis includes stress relaxation due to thermal and irradiation-induced creep. Reduced ductility values from irradiations that simulate the environment of the first wall of a fusion reactor were used to estimate the lifetime of the first wall under irradiation. These results indicate that 20% cold-worked type 316 stainless steel could be used as a first-wall material meeting a 8 to 10 MW-year/m 2 lifetime goal for a neutron wall loading of about 2 MW-year/m 2 and a maximum temperature of about 500 0 C

  4. Estimates of population distributions and tailings areas around licensed uranium mill sites. Final report

    International Nuclear Information System (INIS)

    Hans, J.M.; Hall, J.B.; Moore, W.E.

    1986-08-01

    Population distributions and tailings areas were estimated from aerial photography for each of 21 licensed uranium millsites. Approximately 11,600 persons live within 5 kilometers of the tailings impoundments at the millsites. About 82% of these persons live near five of the millsites. No persons were found living within 5 kilometers of six of the millsites. Tailings area measurements include the surface area of tailings in impoundments, heap-leached ore, and carryover tailings in evaporation ponds. Approximately 4,000 acres of tailings surfaces were measured for the 21 millsites. About 55% of the tailings surfaces were dry, 11% wet, and the remainder ponded. The average tailings surface area for the millsites is about 200 acres and ranges from 7 to 813 acres

  5. Laser fluorimetric analysis of uranium in water from Vishakhapatnam and estimation of health risk

    International Nuclear Information System (INIS)

    Bhangare, R.C.; Tiwari, M.; Ajmal, P.Y.; Sahu, S.K.; Pandit, G.G.

    2014-01-01

    Uranium is a naturally occurring radioactive element that is both radiologically and chemically toxic. The presence of uranium in the aquatic environment is due to the leaching from natural deposits, release in mill tailings, the combustion of coal and other fuels, and the use of phosphate fertilizers that contain uranium up to a concentration of 150g g -1 and contribute to ground water pollution. The most prevalent states of uranium are the hexavalent and tetravalent. The hexavalent state of uranium is particularly important in water because of the insolubility of almost all tetravalent compounds. Uranium enters into human tissues mainly through drinking water, food, air and other occupational and accidental exposures. Intake of uranium through air and water is normally low, but in circumstances in which uranium is present in a drinking water source the majority of intake can be through drinking water. Seeing potential health hazards from natural radionuclides in consuming water, many countries worldwide adopted the guideline activity concentration for drinking water quality recommended by the WHO (2011). For uranium WHO has set limit for drinking water to 30μgL -1 . The main purpose of this study was to measure the level of uranium in drinking water samples from the health hazard point of view and to observe the trend in the variation of uranium content in drinking water from upcoming BARC site at Vishakhapatnam area

  6. Assessment of the meteorological data and atmospheric dispersion estimates in the Ranger 1 Uranium Mining Environmental Impact Statement

    International Nuclear Information System (INIS)

    Clark, G.H.

    1977-03-01

    Wind records from Jabiru, Northern Territory, Australia have been re-analysed to give atmospheric dispersion estimates of sulphur dioxide and radioactive contaminants associated with a proposed uranium mining and milling operation. Revisions in the plume rise equations have led to lower annual average sulphur dioxide air concentrations than those presented in the Ranger 1 Uranium Mining Environmental Impact Statement. Likewise, the short term peak air concentrations of sulphur dioxide were all within the United States Environment Protection Agency air quality standards. Even though the radon gas inventory was revised upwards, predicted concentrations were only slightly higher than those in the RUMEIS. An attempt was made at a first estimate of the uranium dust source term caused by wind suspension from stockpiled ore and waste rock. In a preliminary analysis using a 'surface depletion' model, it was estimated that uranium dust air concentrations would be decreased by about an order of magnitude when dry deposition was included in the atmospheric dispersion model. Integrating over all sources, radionuclides and meteorological conditions, the annual radiation dose to members of the public in the Regional Centre is estimated to be a maximum of 5 per cent of the recommended annual limits. (author)

  7. Coding Partitions

    Directory of Open Access Journals (Sweden)

    Fabio Burderi

    2007-05-01

    Full Text Available Motivated by the study of decipherability conditions for codes weaker than Unique Decipherability (UD, we introduce the notion of coding partition. Such a notion generalizes that of UD code and, for codes that are not UD, allows to recover the ``unique decipherability" at the level of the classes of the partition. By tacking into account the natural order between the partitions, we define the characteristic partition of a code X as the finest coding partition of X. This leads to introduce the canonical decomposition of a code in at most one unambiguouscomponent and other (if any totally ambiguouscomponents. In the case the code is finite, we give an algorithm for computing its canonical partition. This, in particular, allows to decide whether a given partition of a finite code X is a coding partition. This last problem is then approached in the case the code is a rational set. We prove its decidability under the hypothesis that the partition contains a finite number of classes and each class is a rational set. Moreover we conjecture that the canonical partition satisfies such a hypothesis. Finally we consider also some relationships between coding partitions and varieties of codes.

  8. 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

  9. Fission track dating and estimation of uranium in some garnets of Rajasthan (India)

    Energy Technology Data Exchange (ETDEWEB)

    Singh, S; Virk, H S [Punjabi Univ., Patiala (India). Dept. of Physics

    1978-09-01

    The experimental procedure, involving the preparation, etching, thermal neutron irradiation and scanning of the garnet samples, is described. The calculated fission track ages and uranium concentration are tabulated.

  10. 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.

  11. 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

  12. 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.

  13. Procedures for estimating the radiation dose in the vicinity of uranium mines and mills by direct calculation methodology

    International Nuclear Information System (INIS)

    Coelho, C.P.

    1983-01-01

    A methodology for estimating the radiation doses to the members of the general public, in the vicinity of uranium mines and mills is presented. The data collected in the surveys performed to characterize the neighborhood of the site, and used in this work to estimate the radiation dose, are required by the Regulatory Body, for the purpose of Licensing. Initially, a description is shown of the main processing steps to obtain the uranium concentrate and the critical instalation radionuclides are identified. Following, some studies required to characterize the facility neighborhood are presented, specially those related to geography, demography, metheorology, hydrology and environmental protection. Also, the basic programs for monitoring the facility neighborhood in the pre-operational and operational phases are included. It is then proposed a procedure to estimate inhalation, ingestion and external doses. As an example, the proposed procedure is applied to a hypotetical site. Finally, some aspects related to the applicability of this work are discussed. (Author) [pt

  14. Estimation of radiating conditions in the reservoirs located close uranium mining of regions of Kazakhstan

    International Nuclear Information System (INIS)

    Bakhtin, M.; Kazymbet, P.; Akhmetova, Z.

    2010-01-01

    For the first time by the analysis of capacity of an equivalent doze of scales - radiations, the maintenance radionuclide and heavy metals in water, ground adjournment and hydrobionts the objective estimation of a radioecological condition of reservoirs in places of extraction, processing and warehousing of uranium ores Akmolinsk of area is given. It is shown, that the investigated reservoirs differ among themselves with a weak, average and high mineralization of water. These circumstances can influence essentially behaviour radionuclides at their hit in a reservoir, and consequently, and on radiating conditions arising at it. Capacity of an equivalent doze of scales - radiations in a coastal part of the majority of the investigated reservoirs corresponds to background values ( 2 ) and beta particles (4,75-4,93 part./mines x sm 2 ) also is marked. The analysis of a radioecological situation in river system Aksu has shown, that its basic components - river water, ground adjournment, water plants and fishes test radiating loading: concentration 238 U in water, ground deposits, a cane and fabrics of the perch makes accordingly 0,66±0,21 Bk/l, 210±2,8 Bk/kg, 0,64±0,19 Bk/kg and 2,50±0,11 Bk/kg. Specific activity 226 Ra in water, ground adjournment, plants and fishes made accordingly 0,02±0,005 Bk/l, 32,20±0,45 Bk/kg, 0,78±0,05 Bk/kg and 2,41±0,31 Bk/kg. Complex radioecological conditions in river system 'Kutunguz' is caused by dump in the river of miner waters with mine 1. In river water concentration 238 U, 226 Ra, 210 Po, 230 Th and 210 Pb makes accordingly on the average - 4,54 Bk/l, 0,11 Bk/l, 2,50 Bk/l, 0,1 Bk/l and 0,37 Bk/l. If the maintenance specified radionuclides in a ground before dump of miner waters varied in limits from 33,1 Bk/kg up to 56,5 Bk/kg in places of dump of miner waters it makes in limits from 62,0 Bk/kg up to 122 Bk/kg, and is lower on a watercourse, in area of settlement B eseloe , in 27 km from a place of dumps - from 92,0 Bk/kg up

  15. Estimation of uranium in drinking water samples collected from different locations across Tarapur, India

    International Nuclear Information System (INIS)

    Dusane, C.B.; Maity, Sukanta; Sahu, S.K.; Pandit, G.G.

    2015-01-01

    In this study, drinking water samples were collected from different locations across Tarapur, India for screening uranium contents. Uranium concentrations were determined by differential pulse adsorptive stripping voltammetry (DPASV). Uranium concentration in water samples varied in a wide range from 0.6-7.9 μg L -1 . Results were compared with the international water quality guidelines World Health Organization (WHO, 2011) and were found within the permissible limit. Results were also compared with the safe limit values for drinking water recommended by national organization like Atomic Energy Regulatory Board (AERB). (author)

  16. Survey on basic data of risk estimation of lung cancer among non-uranium miners in China

    International Nuclear Information System (INIS)

    Fu Yinghua; Sun Quanfu; Du Weixia; Lei Suwen; Lei Shujie; Li Xiaoying; Zhang Shouzhi; Qian Yekan; Su Xu

    2009-01-01

    Objective: To investigate the basic data of risk estimation of lung cancer among non-uranium miners in China. Methods: 2836 workers from 24 mines in 9 provinces/regions were face-to-face interviewed to collect information including age at exposure,exposure duration, cigarette smoking among others. Results: Age of the investigated non-uranium miners ranged from 17 to 72 (36.9 ± 8.0) years. The miners received low and poor education, 3% of them were illiterate, 58% with primary and middle school education, only 7% with junior college and higher education. Seventy-five percent of the uranium miners are migrant rural workers. Ethnic minority miners accoungted for 16% of all the investigated miners. Among the migrant rural workers age at initial exposure was estimated to be 29.6 ± 8.0 years. By the time of the investigation, 46.7% of the miners had worked in the mine for five years and longer, working years in the mine was 6.7 ± 6.8 years with a median of 4.1 years. 3.4% of the non-uranium miners began the initial radon exposure in mines before their 18 years of old. 17.5% of the investigated miners reported working more than 8 h every working day. Among the males, 58.0% were current smokers with a median of 16 cigarettes per day. Age to begin the cigarette smoking was 20 years on average. Current smoking rate was age-dependent, the rate as high as 69.2% for the males aged 15-19 years. Current smoking rate was significantly statistically lower in coal mines than that in other mines, 49.0% vs 62.5%. Compared with other miners, more frequent mechanical ventilations were reported by coal miners, Conclusions: In China non-uranium mines, 75% were migrant rural workers, by the time of the investigation about half of them had worked in the mines for at least five years. Non-uranium miners began their mining at 30 years on average, with a very small percentage of 3%, exposed to the mining radon before their 18 years. Current cigarette smoking rate in non-uranium male miners

  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. A study of contaminated soils near Crucea-Botus, ana uranium mine (East Carpathians, Romania): metal distribution and partitioning of natural actinides with implications for vegetation uptake

    Science.gov (United States)

    Petrescu, L.; Bilal, E.

    2012-04-01

    Between 1962 and 2009, National Company of Uranium - CNU, the former Romanian Rare Metals Mining Company, mined over 1,200,000 tones of pitchblende ore in the East Carpathians (Crucea-Botušana area, Bistrita Mountains). The exploration and mining facilities include 32 adits, situated between 780 and 1040 m above sea level. Radioactive waste resulted from mining are disposed next to the mining facilities. Mine dumps (32) cover an area of 364,000 square meters and consist of waste rock (rocks with sub-economic mineralization) and gangue minerals. Older dumps (18) have been already naturally reclaimed by forest vegetation, which played an important role in stabilizing the waste dump cover and in slowing down the uranium migration processes. The soils samples have been collected from different mine dumps in the Crucea-Botušana uranium deposit, mainly from 1, 4, 5, 6, 8, 9, 1/30 and 950 mine waste galleries. Soil samples were collected from the upper part and slope at each mine dump, from the vegetation root zones. Total uranium concentration in soils collected from Crucea-Botušana site ranged from 6.10 to 680.70 ppm, with a mean of 52.48 ppm (dry wt.). Total thorium varies between 7.70 and 115.30 ppm (dry wt.). This indicates that the adsorption of the radioactive elements by the soils is high and variable, influenced by the ore dump - sample relationship. The sequential extraction has emphasized the fact that the uranium is associated with all the mineral fractions present in the soil samples. A great percentage of U can be found in the carbonate (21.77%), organic (15.04%) and oxides fractions (15.88%) - in accordance with the high absorbed/adsorbed properties of this element. The percentage of uranium detected in the exchangeable fraction is rather small - 2.16%. It is also to be expected that the uranium should be irreversible adsorbed by the organic matter and by the clay minerals due to its ionic radius and to its positive charge. The fact that 21.77% of the

  19. Polydimethylsiloxane-air partition ratios for semi-volatile organic compounds by GC-based measurement and COSMO-RS estimation: Rapid measurements and accurate modelling.

    Science.gov (United States)

    Okeme, Joseph O; Parnis, J Mark; Poole, Justen; Diamond, Miriam L; Jantunen, Liisa M

    2016-08-01

    Polydimethylsiloxane (PDMS) shows promise for use as a passive air sampler (PAS) for semi-volatile organic compounds (SVOCs). To use PDMS as a PAS, knowledge of its chemical-specific partitioning behaviour and time to equilibrium is needed. Here we report on the effectiveness of two approaches for estimating the partitioning properties of polydimethylsiloxane (PDMS), values of PDMS-to-air partition ratios or coefficients (KPDMS-Air), and time to equilibrium of a range of SVOCs. Measured values of KPDMS-Air, Exp' at 25 °C obtained using the gas chromatography retention method (GC-RT) were compared with estimates from a poly-parameter free energy relationship (pp-FLER) and a COSMO-RS oligomer-based model. Target SVOCs included novel flame retardants (NFRs), polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), organophosphate flame retardants (OPFRs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). Significant positive relationships were found between log KPDMS-Air, Exp' and estimates made using the pp-FLER model (log KPDMS-Air, pp-LFER) and the COSMOtherm program (log KPDMS-Air, COSMOtherm). The discrepancy and bias between measured and predicted values were much higher for COSMO-RS than the pp-LFER model, indicating the anticipated better performance of the pp-LFER model than COSMO-RS. Calculations made using measured KPDMS-Air, Exp' values show that a PDMS PAS of 0.1 cm thickness will reach 25% of its equilibrium capacity in ∼1 day for alpha-hexachlorocyclohexane (α-HCH) to ∼ 500 years for tris (4-tert-butylphenyl) phosphate (TTBPP), which brackets the volatility range of all compounds tested. The results presented show the utility of GC-RT method for rapid and precise measurements of KPDMS-Air. Copyright © 2016. Published by Elsevier Ltd.

  20. Rapid non-destructive quantitative estimation of urania/ thoria in mixed thorium uranium di-oxide pellets by high-resolution gamma-ray spectrometry

    International Nuclear Information System (INIS)

    Shriwastwa, B.B.; Kumar, Anil; Raghunath, B.; Nair, M.R.; Abani, M.C.; Ramachandran, R.; Majumdar, S.; Ghosh, J.K.

    2001-01-01

    A non-destructive technique using high-resolution gamma-ray spectrometry has been standardised for quantitative estimation of uranium/thorium in mixed (ThO 2 -UO 2 ) fuel pellets of varying composition. Four gamma energies were selected; two each from the uranium and thorium series and the time of counting has been optimised. This technique can be used for rapid estimation of U/Th percentage in a large number of mixed fuel pellets from a production campaign

  1. 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

  2. Estimation of gas-particle partitioning coefficients (Kp) of carcinogenic polycyclic aromatic hydrocarbons in carbonaceous aerosols collected at Chiang-Mai, Bangkok and Hat-Yai, Thailand.

    Science.gov (United States)

    Pongpiachan, Siwatt; Ho, Kin Fai; Cao, Junji

    2013-01-01

    To assess environmental contamination with carcinogens, carbonaceous compounds, water-soluble ionic species and trace gaseous species were identified and quantified every three hours for three days at three different atmospheric layers at the heart of Chiang-Mai, Bangkok and Hat-Yai from December 2006 to February 2007. A DRI Model 2001 Thermal/Optical Carbon Analyzer with the IMPROVE thermal/optical reflectance (TOR) protocol was used to quantify the organic carbon (OC) and elemental carbon (EC) contents in PM10. Diurnal and vertical variability was also carefully investigated. In general, OC and EC mass concentration showed the highest values at the monitoring period of 21.00-00.00 as consequences of human activities at night bazaar coupled with reduction of mixing layer, decreased wind speed and termination of photolysis at nighttime. Morning peaks of carbonaceous compounds were observed during the sampling period of 06:00-09:00, emphasizing the main contribution of traffic emission in the three cities. The estimation of incremental lifetime particulate matter exposure (ILPE) raises concern of high risk of carbonaceous accumulation over workers and residents living close to the observatory sites. The average values of incremental lifetime particulate matter exposure (ILPE) of total carbon at Baiyoke Suit Hotel and Baiyoke Sky Hotel are approximately ten times higher than those air samples collected at Prince of Songkla University Hat-Yai campus corpse incinerator and fish-can manufacturing factory but only slightly higher than those of rice straw burning in Songkla province. This indicates a high risk of developing lung cancer and other respiratory diseases across workers and residents living in high buildings located in Pratunam area. Using knowledge of carbonaceous fractions in PM10, one can estimate the gas-particle partitioning of polycyclic aromatic hydrocarbons (PAHs). Dachs-Eisenreich model highlights the crucial role of adsorption in gas

  3. Computer-assisted decision aid for the estimation of mineral endowment: uranium in the San Juan Basin, New Mexico, a case study

    International Nuclear Information System (INIS)

    Carrigan, F.J.

    1983-01-01

    This methodology comprises two main sections, each executed on a different computer system. The first section, the Geologic Decision Model, has been computerized as an interactive PLATO program. Using the PLATO system, the geologist describes probabilistically the perceived states of geologic processes and conditions. The decision model analyzes this information and computes a probability distribution for mineral occurrence. The second section, the Endowment Simulation Model (program MASTER), is run on the DEC 10 and Cyber 175 computers. Program MASTER takes the product of the Geologic Decision Model, combines it with other data, and produces a probabilistic estimate of mineral endowment for the region being evaluated. Development and testing of the Arizona Appraisal System were carried out simultaneously over a period of about three years. During this period, four geologists from government and industry were called upon four or five times over a period of about a year for a study of the uranium (U 3 O 8 ) endowment in the San Juan Basin of northwestern New Mexico. The results produced by the system consist, for each geologist, of a probability distribution for tons of U 3 O 8 endowment for (1) each partition of each stratigraphic unit, (2) each stratigraphic unit as a whole, (3) ''formations'' or ''merged units'' (groups of stratigraphic units), and (4) the San Juan Basin as a whole (all stratigraphic units). The system also calculates the average distribution across all geologists for the various merged units and for the basin as a whole. The result for the basin as a whole (in thousands of tons) is: mean 3,855, variance 4,108 x 10 9 , and 95th percentile 6,541

  4. Fission track dating and uranium estimation in pegmatitic minerals of Rajasthan state (India)

    Energy Technology Data Exchange (ETDEWEB)

    Singh, S; Virk, H S [Punjabi Univ., Patiala (India). Dept. of Physics

    1978-12-01

    Fission track geochronology of muscovite samples collected from some pegmatitic mines of Bhilwara and Ajmer districts of Rajasthan state (India) has been discussed. The ages obtained suggest the occurrence of Delhi Orogenic Cycle as the last major metamorphic activity in the region. The atomic fraction of uranium in muscovite samples is less than 1 p.p.b.

  5. Uranium solution mining cost estimating technique: means for rapid comparative analysis of deposits

    International Nuclear Information System (INIS)

    Anon.

    1978-01-01

    Twelve graphs provide a technique for determining relative cost ranges for uranium solution mining projects. The use of the technique can provide a consistent framework for rapid comparative analysis of various properties of mining situations. The technique is also useful to determine the sensitivities of cost figures to incremental changes in mining factors or deposit characteristics

  6. Geostatistical ore reserve estimation for a roll-front type uranium deposit (practitioner's guide)

    International Nuclear Information System (INIS)

    Kim, Y.C.; Knudsen, H.P.

    1977-01-01

    This report comprises two parts. Part I contains illustrative examples of each phase of a geostatistical study using a roll-front type uranium deposit. Part II contains five computer programs and comprehensive users' manuals for these programs which are necessary to make a practical geostatistical study

  7. Estimation of polycyclic aromatic hydrocarbon concentrations in the water column based on tissue residues in mussels and salmon: An equilibrium partitioning approach

    International Nuclear Information System (INIS)

    Neff, J.M.; Burns, W.A.

    1996-01-01

    Equilibrium partitioning was used to estimate concentrations of dissolved polycyclic aromatic hydrocarbons (PAHs) in the water column from PAH residues in tissues of mussels and juvenile pink salmon collected from coastal marine waters affected by the Exxon Valdez oil spill. Estimated concentrations were within factors of 2 to 5 for fish and 5 to 10 for mussels of average total dissolved and particulate PAHs measured in concurrent water samples. Temporal trends of estimated and measured water-column PAH concentrations were comparable. Water-column PAH concentrations estimated from residues in tissues of mussels (Mytilus trossulus) were higher than estimates based on residues in tissues of juvenile pink salmon (Oncorhynchus gorbuscha). Possible reasons for this difference include seasonal variations in mussel lipid content, differences in PAH uptake and depuration rates between fish and mussels, differences in how fish and mussels interact with particulate oil, and possible short exposure times for juvenile pink salmon. All of these factors may play a role. In any event, estimates of dissolved PAHs in the water column, based on PAH residues in either fish or mussel tissue, confirm that PAH concentrations generally did not exceed water quality standards for protection of marine life

  8. 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

  9. 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.

  10. 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

  11. Plutonic mobilization, sodium metasomatism, propylitic wall-rock alteration and element partitioning from Hoehensteinweg uranium occurrence (Northeast Bavaria, F.R.G.)

    International Nuclear Information System (INIS)

    Dill, H.

    1983-01-01

    The investigated U deposit near Poppenreuth (Hoehensteinweg) in northeast Bavaria is situated among Upper Proterozoic biotite gneisses and mica schists with ENE- to NE-striking foliation. In this paper, the element distribution is determined of the elements involved in the U-Th petrogenic cycle (Zr, Ce, Th, U, P and Na); as are the mineralogical changes of the primary U minerals. The problem of lithogene element supply is studied. The area abundant in U is compared with other U-bearing sodium enriched host rocks in order to improve the selection of exploration target areas. Content: the primary U and Th minerals; plutonic mobilizates; episyenites and sodium metasomatites; propylitic rocks; U minerals and their relation to the primary U minerals; the origin of Hoehensteinweg uranium deposits. (Auth.)

  12. Plutonic mobilization, sodium metasomatism, propylitic wall-rock alteration and element partitioning from Hoehensteinweg uranium occurrence (Northeast Bavaria, F. R. G. )

    Energy Technology Data Exchange (ETDEWEB)

    Dill, H. (Bundesanstalt fuer Geowissenschaften und Rohstoffe, Hannover (Germany, F.R.))

    1983-05-01

    The investigated U deposit near Poppenreuth (Hoehensteinweg) in northeast Bavaria is situated among Upper Proterozoic biotite gneisses and mica schists with ENE- to NE-striking foliation. In this paper, the element distribution is determined of the elements involved in the U-Th petrogenic cycle (Zr, Ce, Th, U, P and Na); as are the mineralogical changes of the primary U minerals. The problem of lithogene element supply is studied. The area abundant in U is compared with other U-bearing sodium enriched host rocks in order to improve the selection of exploration target areas. Content: the primary U and Th minerals; plutonic mobilizates; episyenites and sodium metasomatites; propylitic rocks; U minerals and their relation to the primary U minerals; the origin of Hoehensteinweg uranium deposits.

  13. Application of fission track technique for estimation of uranium concentration in drinking waters of Punjab

    International Nuclear Information System (INIS)

    Prabhu, S.P.; Raj, Sanu S.; Sawant, P.D.; Kumar, Ajay; Sarkar, P.K.; Tripathi, R.M.

    2010-01-01

    Full text: Drinking water samples were collected from four different districts, namely Bhatinda, Mansa, Faridkot and Firozpur, of Punjab for ascertaining the U(nat.) concentrations. The samples were collected from bore wells, hand pumps, tube wells and treated municipal water supply. All these samples (235 nos.) collected were preserved and processed by following the international standard protocol and analyzed by Laser Fluorimetry. Results of analysis by laser fluorimetry have been already reported. To ensure accuracy of the data obtained by laser fluorimetry, few samples (10 nos) from each district were analyzed by alpha spectrometry as well as by fission track analysis (FTA) technique. FTA in solution media for uranium has been already standardized in Bioassay laboratory of Health Physics Division. Few of drinking water sample was directly transferred to polythene tube sealed at one end. Lexan detector with proper identification mark was immersed in the samples and the other open end of the tube was also heat-sealed. Two tubes containing samples and one containing uranium standard (80 ppb) were irradiated in the Pneumatic Carrier Facility (PCF) of DHRUVA reactor. The Lexan detectors were then chemically etched and tracks were counted under an optical microscope at 400X magnification. Concentration of uranium in sample was determined by comparison technique. Quality assurance was carried out by replicate analysis and by analysis of standard reference materials. Uranium concentration in these samples ranged from 3.2 to 60.5 ppb with an average of 28.8 ppb. A t-test analysis for paired data was done to compare the results obtained by FTA and those obtained by laser fluorimeter. The calculated value for t is -1.19, which is greater than the tabulated value of t for 40 observations (-2.02 at 95% confidence level). This shows that the results of the measurements carried out by the FTA and laser fluorimetry are not significantly different. The preliminary studies

  14. Application of fission track technique for estimation of uranium concentration in drinking waters of Punjab

    International Nuclear Information System (INIS)

    Prabhu, S.P.; Sawant, P.D.; Raj, S.S.; Kumar, A.; Sarkar, P.K.; Tripathi, R.M.

    2012-01-01

    Drinking water samples were collected from four different districts, namely Bhatinda, Mansa, Faridkot and Firozpur, of Punjab for ascertaining the U(nat.) concentrations. All samples were preserved, processed and analyzed by laser fluorimetry (LF). To ensure accuracy of the data obtained by LF, few samples (10 nos) from each district were analyzed by alpha spectrometry as well as by fission track analysis (FTA) technique. For FTA technique few μl of water sample was transferred to polythene tube, lexan detector was immersed in it and the other end of the tube was also heat-sealed. Two samples and one uranium standard were irradiated in DHRUVA reactor. Irradiated detectors were chemically etched and tracks counted using an optical microscope. Uranium concentrations in samples ranged from 3.2 to 60.5 ppb and were comparable with those observed by LF. (author)

  15. Estimates of naturally occurring pools of thorium, uranium and iodine in boreal forests of southeast Sweden

    International Nuclear Information System (INIS)

    Loefgren, A.; Kautsky, U.

    2009-01-01

    The distribution patterns of naturally occurring radionuclides or their stable isotopes have been used to study the long-term behaviour of the radionuclides that may originate from nuclear waste. The Swedish Nuclear Fuel and Waste Management Company is performing investigations at two potential sites for nuclear waste disposal in southern Sweden. Here is the distribution and total content of the three naturally occurring radionuclides/stable isotopes, thorium, uranium and iodine, described for six forest localities at those sites. (LN)

  16. Estimating the concentration of uranium in some environmental samples in Kuwait after the 1991 Gulf War

    International Nuclear Information System (INIS)

    Bou-Rabee, F.

    1995-01-01

    The concentration of uranium in Kuwait soil samples as well as in solid fall-out and surface air-suspended matter samples has been assayed by inductively coupled plasma mass spectrometry (ICP-MS). It was found that average U concentration in the soil samples (∼ 0.7 μg/g) is half of that in solid fall-out and air particulate matter samples. The average U concentration in the latter samples in the summer season was 2 μg g -1 and decreased to 1 μg g -1 during the winter of 1993/94. The higher concentration in the solid fall-out and air samples cannot be explained by fall-out from the oil fired power station as the U average concentration of the escaping fly ashes from the station was only 0.22 μg g -1 . The uranium concentration in the tap water was a very low 0.02 μg L -1 . The total per capita annual intake of uranium via inhalation by Kuwait inhabitants was appraised to be ''approx =''0.05 Bq, which is <0.2% of the recommended annual limit on intake for members of the general population. (author)

  17. Using carbon emissions, oxygen consumption, and energy retention estimates to calculate dietary energy partitioning and estimate forage intake by beef steers

    Science.gov (United States)

    Take home Message: Estimating ME intake by grazing cattle seems possible using respiration gas exchange estimates. Introduction: We hypothesized that carbon dioxide, methane, and oxigen exchange estimates in breath clouds could be used as biomarkers to ultimately estimate dry matter intake in grazi...

  18. [Application of reversed-phase ion-pair chromatography for universal estimation of octanol-water partition coefficients of acid, basic and amphoteric drugs].

    Science.gov (United States)

    Zhu, Hui; Yang, Ri-Fang; Yun, Liu-Hong; Jiang, Yu; Li, Jin

    2009-09-01

    This paper is to establish a reversed-phase ion-pair chromatography (RP-IPC) method for universal estimation of the octanol/water partition coefficients (logP) of a wide range of structurally diverse compounds including acidic, basic, neutral and amphoteric species. The retention factors corresponding to 100% water (logk(w)) were derived from the linear part of the logk'/phi relationship, using at least four isocratic logk' values containing different organic compositions. The logk(w) parameters obtained were close to the corresponding logP values obtained with the standard "shake flask" methods. The mean deviation for test drugs is 0.31. RP-IPC with trifluoroacetic acid as non classic ion-pair agents can be applicable to determine the logP values for a variety of drug-like molecules with increased accuracy.

  19. The parent magma of the Nakhla (SNC) meteorite: Reconciliation of composition estimates from magmatic inclusions and element partitioning

    Science.gov (United States)

    Treiman, A. H.

    1993-01-01

    The composition of the parent magma of the Nakhla meteorite was difficult to determine, because it is accumulate rock, enriched in olivine and augite relative to a basalt magma. A parent magma composition is estimated from electron microprobe area analyses of magmatic inclusions in olivine. This composition is consistent with an independent estimate based on the same inclusions, and with chemical equilibria with the cores of Nakhla's augites. This composition reconciles most of the previous estimates of Nakhla's magma composition, and obviates the need for complex magmatic processes. Inconsistency between this composition and those calculated previously suggests that magma flowed through and crystallized into Nakhla as it cooled.

  20. Identification and quantitative grade estimation of Uranium mineralization based on gross-count gamma ray log at Lemajung sector West Kalimantan

    International Nuclear Information System (INIS)

    Adi Gunawan Muhammad

    2014-01-01

    Lemajung sector, is one of uranium potential sector in Kalan Area, West Kalimantan. Uranium mineralization is found in metasiltstone and schistose metapelite rock with general direction of mineralization east - west tilted ± 70° to the north parallel with schistocity pattern (S1). Drilling evaluation has been implemented in 2013 in Lemajung sector at R-05 (LEML-(S1). Drilling evaluation has been implemented in 2013 in Lemajung sector at R-05 (LEML-gamma ray. The purpose of this activity is to determine uranium mineralization grade with quantitatively methode in the rocks and also determine the geological conditions in sorounding of drilling area. The methodology involves determining the value of k-factor, geological mapping for the sorounding of drill hole, determination of the thickness and grade estimation of uranium mineralization with gross-count gamma ray. Quantitatively from grade estimation of uranium using gross-count gamma ray log can be known that the highest % eU_3O_8 in the hole R-05 (LEML-40) reaches 0.7493≈6354 ppm eU found at depth interval from 30.1 to 34.96 m. Uranium mineralization is present as fracture filling (vein) or tectonic breccia matrix filling in metasiltstone with thickness from 0.10 to 2.40 m associated with sulphide (pyrite) and characterized by high ratio of U/Th. (author)

  1. 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

  2. Integrating spot short-term measurements of carbon emissions and backward dietary energy partition calculations to estimate intake in lactating dairy cows fed ad libitum or restricted.

    Science.gov (United States)

    Pereira, A B D; Utsumi, S A; Dorich, C D; Brito, A F

    2015-12-01

    The objective of this study was to use spot short-term measurements of CH4 (QCH4) and CO2 (QCO2) integrated with backward dietary energy partition calculations to estimate dry matter intake (DMI) in lactating dairy cows. Twelve multiparous cows averaging 173±37d in milk and 4 primiparous cows averaging 179±27d in milk were blocked by days in milk, parity, and DMI (as a percentage of body weight) and, within each block, randomly assigned to 1 of 2 treatments: ad libitum intake (AL) or restricted intake (RI=90% DMI) according to a crossover design. Each experimental period lasted 22d with 14d for treatments adaptation and 8d for data and sample collection. Diets contained (dry matter basis): 40% corn silage, 12% grass-legume haylage, and 48% concentrate. Spot short-term gas measurements were taken in 5-min sampling periods from 15 cows (1 cow refused sampling) using a portable, automated, open-circuit gas quantification system (GreenFeed, C-Lock Inc., Rapid City, SD) with intervals of 12h between the 2daily samples. Sampling points were advanced 2h from a day to the next to yield 16 gas samples per cow over 8d to account for diurnal variation in QCH4 and QCO2. The following equations were used sequentially to estimate DMI: (1) heat production (MJ/d)=(4.96 + 16.07 ÷ respiratory quotient) × QCO2; respiratory quotient=0.95; (2) metabolizable energy intake (MJ/d)=(heat production + milk energy) ± tissue energy balance; (3) digestible energy (DE) intake (MJ/d)=metabolizable energy + CH4 energy + urinary energy; (4) gross energy (GE) intake (MJ/d)=DE + [(DE ÷ in vitro true dry matter digestibility) - DE]; and (5) DMI (kg/d)=GE intake estimated ÷ diet GE concentration. Data were analyzed using the MIXED procedure of SAS (SAS Institute Inc., Cary, NC) and Fit Model procedure in JMP (α=0.05; SAS Institute Inc.). Cows significantly differed in DMI measured (23.8 vs. 22.4kg/d for AL and RI, respectively). Dry matter intake estimated using QCH4 and QCO2 coupled with

  3. An attempt for economic estimate of the shutdown of uranium production

    International Nuclear Information System (INIS)

    Jonchev, L.

    1997-01-01

    Uranium ore has been obtained since the end of 30s till 1992. No measures for protection of the environment and restricting the risk for the population during the production have been taken. Among the three possible models of shutting down the most inexpedient from economic point of view has been applied . It meant that the beginning of closing down took place far behind ceasing the production itself and the expenses for restoration were as big as fourteen times more in comparison to the two ones. The investments for prospecting and preparing new resources were lost. The whole process was made extremely inefficiently and unprofessionally. Because of the sudden closing down of production activities there was no enough time for gathering, processing and analyzing of necessary data, even the radioecological and hydro-ecological evaluations were doubtfully reliable. The shutdown of uranium production as worldwide practice takes place considering ALARA (As Low As Reasonably Achievable) principle. The aim is to achieve maximum possible results by minimum investments taking into account the radioecological risk, socially accounted for and psychologically conditioned expenses. There is no statement of the radioecological risk in the preliminary evaluations of the uranium mines in Bulgaria. The investment funds for the period 1992-1996 were about 2.1 bill. leva, (equally allocated for each year) which was about 46.5 mil. US$. Because of inflation process the investments crucially decreased during the last years when most capital-intensive activities had to be carried out - the engineering shutdown and land-reclamations procedures. The biggest share of investments (about 30 mil. US$) was for environmental status maintenance, 2.5 times less (about 13 mil. US$) - for technical shutdown and only 2.1 mil. US$ - for land reclamation. The investments for the shutdown process referred to the whole production obtained were only 2.5 US$/kg U 3 O 8 while the most effective model

  4. Robust extrapolation scheme for fast estimation of 3D Ising field partition functions: application to within subject fMRI data

    Energy Technology Data Exchange (ETDEWEB)

    Risser, L.; Vincent, T.; Ciuciu, Ph. [NeuroSpin CEA, F-91191 Gif sur Yvette (France); Risser, L.; Vincent, T. [Laboratoire de Neuroimagerie Assistee par Ordinateur (LNAO) CEA - DSV/I2BM/NEUROSPIN (France); Risser, L. [Institut de mecanique des fluides de Toulouse (IMFT), CNRS: UMR5502 - Universite Paul Sabatier - Toulouse III - Institut National Polytechnique de Toulouse - INPT (France); Idier, J. [Institut de Recherche en Communications et en Cybernetique de Nantes (IRCCyN) CNRS - UMR6597 - Universite de Nantes - ecole Centrale de Nantes - Ecole des Mines de Nantes - Ecole Polytechnique de l' Universite de Nantes (France)

    2009-07-01

    In this paper, we present a first numerical scheme to estimate Partition Functions (PF) of 3D Ising fields. Our strategy is applied to the context of the joint detection-estimation of brain activity from functional Magnetic Resonance Imaging (fMRI) data, where the goal is to automatically recover activated regions and estimate region-dependent, hemodynamic filters. For any region, a specific binary Markov random field may embody spatial correlation over the hidden states of the voxels by modeling whether they are activated or not. To make this spatial regularization fully adaptive, our approach is first based upon it, classical path-sampling method to approximate a small subset of reference PFs corresponding to pre-specified regions. Then, file proposed extrapolation method allows its to approximate the PFs associated with the Ising fields defined over the remaining brain regions. In comparison with preexisting approaches, our method is robust; to topological inhomogeneities in the definition of the reference regions. As a result, it strongly alleviates the computational burden and makes spatially adaptive regularization of whole brain fMRI datasets feasible. (authors)

  5. Rapid non-destructive quantitative estimation of urania/ thoria in mixed thorium uranium di-oxide pellets by high-resolution gamma-ray spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Shriwastwa, B.B.; Kumar, Anil; Raghunath, B.; Nair, M.R.; Abani, M.C.; Ramachandran, R.; Majumdar, S.; Ghosh, J.K

    2001-06-01

    A non-destructive technique using high-resolution gamma-ray spectrometry has been standardised for quantitative estimation of uranium/thorium in mixed (ThO{sub 2}-UO{sub 2}) fuel pellets of varying composition. Four gamma energies were selected; two each from the uranium and thorium series and the time of counting has been optimised. This technique can be used for rapid estimation of U/Th percentage in a large number of mixed fuel pellets from a production campaign.

  6. Estimation of uranium isotopes in soil affected by Fukushima nuclear power plant accident and its mobility based on distribution coefficient and soil properties

    Energy Technology Data Exchange (ETDEWEB)

    Sahoo, S.K. [National Institute of Radiological Sciences (Japan); Mishra, S. [Bhabha Atomic Research Centre (India); Sorimachi, A.; Hosoda, M.; Tokonami, S. [Hirosaki University (Japan); Kritsananuwat, R. [Tokyo Metropolitan University (Japan); Ishikawa, T. [Fukushima Medical University (Japan)

    2014-07-01

    An extraordinary earthquake of magnitude 9.0 followed by Tsunami on 11 March 2011 caused serious nuclear accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP) about 250 km north to Tokyo, capital of Japan. This resulted in radioactive contamination due to deposition of long-lived radionuclides. Contaminated soil can cause an enhanced radiation exposure even after many years. Depending upon environmental conditions radionuclides can be mobilized to aquatic systems. Therefore, the fate and transfer of these radionuclides in the soil water system is very important for radiation protection and dose assessment. In the present study, emphasis has been given on isotope ratio measurement of uranium that may give some idea about its contamination during accident. Soil and water samples were collected from contaminated areas around FDNPP. Inductively coupled plasma mass spectrometry (ICPMS) is used for total uranium concentration and thermal ionization mass spectrometry (TIMS) has been used for uranium isotopes measurement. Extraction chromatography has been used for the separation of uranium. We have observed, isotope ratio {sup 235}U/{sup 238}U is of natural origin, however in a few soil samples {sup 236}U has been detected. For the migration behavior, its distribution coefficient (K{sub d}) has been determined using laboratory batch method. Depleted uranium is used as tracer for uranium K{sub d} estimation. Chemical characterization of soil with respect to different parameters has been carried out. The effect of these soil parameters on distribution coefficient of uranium has been studied in order to explain the radionuclide mobility in this particular area. The distribution coefficient values for uranium are found to vary from 30-35679 L/Kg. A large variation in the distribution coefficient values shows the retention or mobility of uranium is highly dependent on soil characteristics in the particular area. This variation is explained with respect to pH, Fe, Mn

  7. Estimation of distribution coefficient for uranium in soil around a waste disposal site at Trombay

    International Nuclear Information System (INIS)

    Mishra, S.; Chaudhary, D.K.; Sandeep, P.; Pandit, G.G.

    2014-01-01

    Soil contamination arising from the disposed waste from industrial origin is of major concern now a days. There is a possibility of run off as well as Ieaching of contaminants from the sites to nearby aquatic bodies through rain water. Distribution coefficient, K d in soil is an important parameter to predict the migration of contaminants. However it requires precise measurement not only for the accurate prediction of contaminant transport but also for describing the sorption behavior in a particular environment. The variation of K d values for a radionuclide is due to differences in geochemical conditions, soil materials, nature of water and methods used for the measurements. For the present study soil samples have been collected near a waste disposal site at Trombay and the sorption of uranium has been studied by measuring the distribution coefficient (K d ) by laboratory batch method. In our earlier studies, we could notice substantial effect of ionic composition of ground water on the K d values of uranium. In this study we have used rain water as the sorption media and the measured K d value s were compared with previous values for different soil and water characteristics from different regions of India

  8. 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

  9. Use of the Boron partition coefficient ‘KD’ and B/Ca from planktonic foraminifera in the estimation of past seawater pCO2

    Digital Repository Service at National Institute of Oceanography (India)

    Naik, S.S.; Naidu, P.D.

    We assess the usefulness of the empirical boron partition coefficient, KD and B/Ca measured from planktonic foraminifera in estimation of pCO2 using three different relationships between KD and temperature derived...

  10. Uranium-Series Constraints on Subrepository Water Flow at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    L.A. Neymark; J.B. Paces; S.J. Chipera; D.T. Vaniman

    2006-01-01

    Mineral abundances and whole-rock chemical and uranium-series isotopic compositions were measured in unfractured and rubble core samples from borehole USWSD-9 in the same layers of variably zeolitized tuffs that underlie the proposed nuclear waste repository at Yucca Mountain, Nevada. Uranium concentrations and isotopic compositions also were measured in pore water from core samples from the same rock units and rock leachates representing loosely bound U adsorbed on mineral surfaces or contained in readily soluble secondary minerals. The chemical and isotopic data were used to evaluate differences in water-rock interaction between fractured and unfractured rock and between fracture surfaces and rock matrix. Samples of unfractured and rubble fragments (about 1 centimeter) core and material from fracture surfaces show similar amounts of uranium-series disequilibrium, recording a complex history of sorption and loss of uranium over the past 1 million years. The data indicate that fractures in zeolitized tuffs may not have had greater amounts of water-rock interaction than the rock matrix. The data also show that rock matrix from subrepository units is capable of scavenging uranium with elevated uranium-234/uranium-238 from percolating water and that retardation of radionuclides and dose reduction may be greater than currently credited to this aspect of the natural barrier. Uranium concentrations of pore water and the rock leachates are used to estimate long-term in situ uranium partition coefficient values greater than 7 milliliters per gram

  11. 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.

  12. Comparison of modeling approaches for carbon partitioning: Impact on estimates of global net primary production and equilibrium biomass of woody vegetation from MODIS GPP

    Science.gov (United States)

    Takeshi Ise; Creighton M. Litton; Christian P. Giardina; Akihiko Ito

    2010-01-01

    Partitioning of gross primary production (GPP) to aboveground versus belowground, to growth versus respiration, and to short versus long�]lived tissues exerts a strong influence on ecosystem structure and function, with potentially large implications for the global carbon budget. A recent meta-analysis of forest ecosystems suggests that carbon partitioning...

  13. Polyacrylate–water partitioning of biocidal compounds: Enhancing the understanding of biocide partitioning between render and water

    DEFF Research Database (Denmark)

    Bollmann, Ulla E.; Ou, Yi; Mayer, Philipp

    2014-01-01

    -N-octylisothiazolinone). The correlation of the polyacrylate-water partition constants with the octanol-water partition constants is significant, but the polyacrylate-water partition constants were predominantly below octanol-water partition constants (Kow). The comparison with render-water distribution constants showed that estimating...

  14. Aquatic pathway variables affecting the estimation of dose commitment from uranium mill tailings

    International Nuclear Information System (INIS)

    Lush, D.L.; Snodgrass, W.J.; McKee, P.

    1982-01-01

    As one of a series of studies being carried out for the Atomic Energy Control Board of Canada, the environmental variables affecting population dose commitment and critical group dose rates from aquatic pathways were investigated. A model was developed to follow uranium and natural thorium decay series radionuclides through aquatic pathways leading both to long-term sediment sinks and to man. Pathways leading to man result in both a population dose commitment and a critical group dose rate. The key variables affecting population dose commitment are suspended particulate concentrations in the receiving aquatic systems, the settling velocities of these particulates and the solid-aqueous phase distribution coefficient associated with each radionuclide. Of secondary importance to population dose commitment are the rate at which radionuclides enter the receiving waters and the value of the water to food transfer coefficients that are used in the model. For the critical group dose rate, the rate at which the radionuclides leave the tailings, the water to food transfer coefficients, the rate of water and fish consumption and the dose conversion factors for 210 Pb and 210 Po are of secondary importance (author)

  15. Oligomeric models for estimation of polydimethylsiloxane-water partition ratios with COSMO-RS theory: impact of the combinatorial term on absolute error.

    Science.gov (United States)

    Parnis, J Mark; Mackay, Donald

    2017-03-22

    A series of 12 oligomeric models for polydimethylsiloxane (PDMS) were evaluated for their effectiveness in estimating the PDMS-water partition ratio, K PDMS-w . Models ranging in size and complexity from the -Si(CH 3 ) 2 -O- model previously published by Goss in 2011 to octadeca-methyloctasiloxane (CH 3 -(Si(CH 3 ) 2 -O-) 8 CH 3 ) were assessed based on their RMS error with 253 experimental measurements of log K PDMS-w from six published works. The lowest RMS error for log K PDMS-w (0.40 in log K) was obtained with the cyclic oligomer, decamethyl-cyclo-penta-siloxane (D5), (-Si(CH 3 ) 2 -O-) 5 , with the mixing-entropy associated combinatorial term included in the chemical potential calculation. The presence or absence of terminal methyl groups on linear oligomer models is shown to have significant impact only for oligomers containing 1 or 2 -Si(CH 3 ) 2 -O- units. Removal of the combinatorial term resulted in a significant increase in the RMS error for most models, with the smallest increase associated with the largest oligomer studied. The importance of inclusion of the combinatorial term in the chemical potential for liquid oligomer models is discussed.

  16. Min-max Extrapolation Scheme for Fast Estimation of 3D Potts Field Partition Functions. Application to the Joint Detection-Estimation of Brain Activity in fMRI

    International Nuclear Information System (INIS)

    Risser, L.; Vincent, T.; Ciuciu, P.; Risser, L.; Idier, J.; Risser, L.; Forbes, F.

    2011-01-01

    In this paper, we propose a fast numerical scheme to estimate Partition Functions (PF) of symmetric Potts fields. Our strategy is first validated on 2D two-color Potts fields and then on 3D two- and three-color Potts fields. It is then applied to the joint detection-estimation of brain activity from functional Magnetic Resonance Imaging (fMRI) data, where the goal is to automatically recover activated, deactivated and inactivated brain regions and to estimate region dependent hemodynamic filters. For any brain region, a specific 3D Potts field indeed embodies the spatial correlation over the hidden states of the voxels by modeling whether they are activated, deactivated or inactive. To make spatial regularization adaptive, the PFs of the Potts fields over all brain regions are computed prior to the brain activity estimation. Our approach is first based upon a classical path-sampling method to approximate a small subset of reference PFs corresponding to pre-specified regions. Then, we propose an extrapolation method that allows us to approximate the PFs associated to the Potts fields defined over the remaining brain regions. In comparison with preexisting methods either based on a path sampling strategy or mean-field approximations, our contribution strongly alleviates the computational cost and makes spatially adaptive regularization of whole brain fMRI datasets feasible. It is also robust against grid inhomogeneities and efficient irrespective of the topological configurations of the brain regions. (authors)

  17. Estimated inventory of plutonium and uranium radionuclides for vegetation in aged fallout areas

    International Nuclear Information System (INIS)

    Romney, E.M.; Wallace, A.; Kinnear, J.; Gilbert, R.O.

    1977-01-01

    Data are presented pertinent to the contamination of vegetation by plutonium and other radionuclides in aged fallout areas on the Nevada Test Site (NTS) and the Tonopah Test Range (TTR). The standing biomass of vegetation estimated by nondestructive dimensional methods varied from about 200 to 600 g/m 2 for the different fallout areas. Estimated inventories of 238 Pu, 239 Pu, 240 Pu, and 235 U in plants and their biological effects are discussed

  18. Radionuclide Partitioning in an Underground Nuclear Test Cavity

    Energy Technology Data Exchange (ETDEWEB)

    Rose, T P; Hu, Q; Zhao, P; Conrado, C L; Dickerson, R; Eaton, G F; Kersting, A B; Moran, J E; Nimz, G; Powell, B A; Ramon, E C; Ryerson, F J; Williams, R W; Wooddy, P T; Zavarin, M

    2009-01-09

    In 2004, a borehole was drilled into the 1983 Chancellor underground nuclear test cavity to investigate the distribution of radionuclides within the cavity. Sidewall core samples were collected from a range of depths within the re-entry hole and two sidetrack holes. Upon completion of drilling, casing was installed and a submersible pump was used to collect groundwater samples. Test debris and groundwater samples were analyzed for a variety of radionuclides including the fission products {sup 99}Tc, {sup 125}Sb, {sup 129}I, {sup 137}Cs, and {sup 155}Eu, the activation products {sup 60}Co, {sup 152}Eu, and {sup 154}Eu, and the actinides U, Pu, and Am. In addition, the physical and bulk chemical properties of the test debris were characterized using Scanning Electron Microscopy (SEM) and Electron Microprobe measurements. Analytical results were used to evaluate the partitioning of radionuclides between the melt glass, rubble, and groundwater phases in the Chancellor test cavity. Three comparative approaches were used to calculate partitioning values, though each method could not be applied to every nuclide. These approaches are based on: (1) the average Area 19 inventory from Bowen et al. (2001); (2) melt glass, rubble, and groundwater mass estimates from Zhao et al. (2008); and (3) fission product mass yield data from England and Rider (1994). The U and Pu analyses of the test debris are classified and partitioning estimates for these elements were calculated directly from the classified Miller et al. (2002) inventory for the Chancellor test. The partitioning results from this study were compared to partitioning data that were previously published by the IAEA (1998). Predictions of radionuclide distributions from the two studies are in agreement for a majority of the nuclides under consideration. Substantial differences were noted in the partitioning values for {sup 99}Tc, {sup 125}Sb, {sup 129}I, and uranium. These differences are attributable to two factors

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  20. Uranium resources, demand and production

    International Nuclear Information System (INIS)

    Stipanicic, P.N.

    1985-05-01

    Estimations of the demand and production of principal uranium resource categories are presented. The estimations based on data analysis made by a joint 'NEA/IAEA Working Party on Uranium Resources' and the corresponding results are published by the OECD (Organization for Economic Co-operation and Development) in the 'Uranium Resources, Production and Demand' Known as 'Red Book'. (M.C.K.) [pt

  1. Biological characterization of radiation exposure and dose estimates for inhaled uranium milling effluents. Annual progress report April 1, 1982-March 31, 1983

    International Nuclear Information System (INIS)

    Eidson, A.F.

    1984-05-01

    The problems addressed are the protection of uranium mill workers from occupational exposure to uranium through routine bioassay programs and the assessment of accidental worker exposures. Comparisons of chemical properties and the biological behavior of refined uranium ore (yellowcake) are made to identify important properties that influence uranium distribution patterns among organs. These studies will facilitate calculations of organ doses for specific exposures and associated health risk estimates and will identify important bioassay procedures to improve evaluations of human exposures. A quantitative analytical method for yellowcake was developed based on the infrared absorption of ammonium diuranate and U 3 O 8 mixtures in KBr. The method was applied to yellowcake samples obtained from six operating mills. The composition of yellowcake from the six mills ranged from nearly pure ammonium diuranate to nearly pure U 3 O 8 . The composition of yellowcake samples taken from lots from the same mill was only somewhat less variable. Because uranium mill workers might be exposed to yellowcake either by contamination of a wound or by inhalation, a study of retention and translocation of uranium after subcutaneous implantation in rats was done. The results showed that 49% of the implanted yellowcake cleared from the body with a half-time (T sub 1/2) in the body of 0.3 days, and the remainder was cleared with a T sub 1/2 of 11 to 30 days. Exposures of Beagle dogs by nose-only inhalation to aerosols of commercial yellowcake were completed. Biochemical indicators of kidney dysfunction that appeared in blood and urine 4 to 8 days after exposure to the more soluble yellowcake showed significant changes in dogs, but levels returned to normal by 16 days after exposure. No biochemical evidence of kidney dysfunction was observed in dogs exposed to the less soluble yellowcake form. 18 figures, 9 tables

  2. 232Th/238U in a uranium mobility estimate in an agricultural area in the municipality of Pedra-Pernambuco - Brazil

    International Nuclear Information System (INIS)

    Santos Junior, Jose Araujo dos; Amaral, Romilton dos Santos; Bezerra, Jairo Dias; Damascena, Kennedy Francys Rodrigues; Oliveira, Jose Valdez Monterazo de; Bispo, Rodrigo Cesar Bezerra; Silva, Cleomacio Miguel da; Rocha, Edilson Accioly

    2011-01-01

    The mobility of the radionuclides in soil depends primarily on the physic-chemical parameters. The uranium is easily oxidized in aqueous environment, which allows its characterization with higher mobility. The Thorium is practically insoluble, mainly if the environment has organic matter and sulfates. The geochemical characteristics of the rocks, associated with the weather and metamorphism produce alterations in the concentration diagrams of the natural radionuclides in different types of soil. The ratio 232 Th/ 238 U has been used as an indicator of oxidizing and reducing conditions. Th/U less than 2 suggests that the uranium is in its concentrated form abundantly when compared to the thorium. In reducing conditions, the value Th/U higher than 7 indicates a removal of the uranium. In this work it was possible to analyze the agricultural soil in the municipality of Pedra, Pernambuco, Brazil where there are uranium anomaly and thorium in rocky outcrops. Sixty-two samples of the horizon C soil were collected, in an area of 2 km 2 , where the main uranium occurrences are located. The analyses were done by High-Resolution Gamma-Spectroscopy. In the analyses the secular equilibrium was assumed and the 238 U and the 232 Th specific activities were used to estimate the oxidizing and reducing conditions defining the uranium mobility in the soil. The obtained findings show that the ratio Th/U varied from 0.3 to 13.4, with average of 4.6. The biggest 238 U fraction was fix (80.3%), with low mobility; the smallest fraction concentrated (6.6%) and a lixiviated intermediate fraction (13.1%). (author)

  3. Estimated inventory of plutonium and uranium radionuclides for vegetation in aged fallout areas

    International Nuclear Information System (INIS)

    Romney, E.M.; Gilbert, R.O.; Wallace, A.; Kinnear, J.

    1976-02-01

    Data are presented on the contamination of vegetation by 239 Pu, 240 Pu, and other radionuclides in aged fallout areas on the Nevada Test Site (NTS) and the Tonopah Test Range (TTR). Comparisons of soil and vegetation inventory estimates indicate that the standing vegetation contributes an insignificant portion of the total amount of 239-240 Pu present in these aged fallout areas. The amounts of Pu available for vegetation-transport to animals grazing on-site would appear to be relatively small in comparison to the total amounts deposited upon soil. Findings indicate that most of the contaminant found on vegetation probably is attributable to resuspendable materials

  4. Unique Path Partitions

    DEFF Research Database (Denmark)

    Bessenrodt, Christine; Olsson, Jørn Børling; Sellers, James A.

    2013-01-01

    We give a complete classification of the unique path partitions and study congruence properties of the function which enumerates such partitions.......We give a complete classification of the unique path partitions and study congruence properties of the function which enumerates such partitions....

  5. Estimation of the radiological background and dose assessment in areas with naturally occurring uranium geochemical anomalies—a case study in the Iberian Massif (Central Portugal)

    International Nuclear Information System (INIS)

    Pereira, A.J.S.C.; Neves, L.J.P.F.

    2012-01-01

    Naturally occurring uranium geochemical anomalies, representative of the several thousand recognized in the Portuguese section of the Iberian Massif and outcropping in three target areas with a total of a few thousand square metres, were subjected to a detailed study (1:1000 scale) to evaluate the radiological health-risk on the basis of a dose assessment. To reach this goal some radioactive isotopes from the uranium, thorium and potassium radioactive series were measured in 52 samples taken from different environmental compartments: soils, stream sediments, water, foodstuff (vegetables) and air; external radiation was also measured through a square grid of 10 × 10 m, with a total of 336 measurements. The results show that some radioisotopes have high activities in all the environmental compartments as well as a large variability, namely for those of the uranium decay chain, which is a common situation in the regional geological setting. Isotopic disequilibrium is also common and led to an enrichment of several isotopes in the different pathways, as is the case of 226 Ra; maximum values of 1.76 Bq L −1 (water), 986 Bq kg −1 (soils) and 18.9 Bq kg −1 (in a turnip sample) were measured. On the basis of a realistic scenario combined with the experimental data, the effective dose from exposure to ionizing radiation for two groups of the population (rural and urban) was calculated; the effective dose is variable between 8.0 and 9.5 mSv year −1 , which is 3–4 times higher than the world average. Thus, the radiological health-risk for these populations could be significant and the studied uranium anomalies must be taken into account in the assessment of the geochemical background. The estimated effective dose can also be used as typical of the background of the Beiras uranium metalogenetic province and therefore as a “benchmark” in the remediation of the old uranium mining sites. - Highlights: ► The importance of small-sized naturally occurring uranium

  6. Estimation of terrorist attack resistibility of dual-purpose cask TP-117 with DU (depleted uranium) gamma shield

    International Nuclear Information System (INIS)

    Alekseev, O.G.; Matveev, V.Z.; Morenko, A.I.; Il'kaev, R.I.; Shapovalov, V.I.

    2004-01-01

    Report is devoted to numerical research of dual-purpose unified cask (used for SFA transportation and storage) resistance to terrorist attacks. High resistance of dual-purpose unified cask has been achieved due to the unique design-technological solutions and implementation of depleted uranium in cask construction. In suggested variant of construction depleted uranium fulfils functions of shielding and constructional material. It is used both in metallic and cermet form (basing on steel and depleted uranium dioxide). Implementation of depleted uranium in cask construction allows maximal load in existing overall dimensions of the cask. At the same time: 1) all safety requirements (IAEA) are met, 2) dual-purpose cask with SFA has high resistance to terrorist attacks

  7. Estimation of terrorist attack resistibility of dual-purpose cask TP-117 with DU (depleted uranium) gamma shield

    Energy Technology Data Exchange (ETDEWEB)

    Alekseev, O.G.; Matveev, V.Z.; Morenko, A.I.; Il' kaev, R.I.; Shapovalov, V.I. [Russian Federal Nuclear Center - All-Russian Research Inst. of Experimental Physics, Sarov (Russian Federation)

    2004-07-01

    Report is devoted to numerical research of dual-purpose unified cask (used for SFA transportation and storage) resistance to terrorist attacks. High resistance of dual-purpose unified cask has been achieved due to the unique design-technological solutions and implementation of depleted uranium in cask construction. In suggested variant of construction depleted uranium fulfils functions of shielding and constructional material. It is used both in metallic and cermet form (basing on steel and depleted uranium dioxide). Implementation of depleted uranium in cask construction allows maximal load in existing overall dimensions of the cask. At the same time: 1) all safety requirements (IAEA) are met, 2) dual-purpose cask with SFA has high resistance to terrorist attacks.

  8. 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 not yet in use. In the near future, the most reasonable source for developing uranium is phosphate rock. Uranium reserves in phosphates are estimated at a few million tons. Production of uranium from phosphates is as a by-product of phosphate rock processing and phosphoric acid production; it will then be possible to save the costs incurred in crushing and dissolving the rock when calculating uranium production costs. Estimates show that the U.S. wastes about 3,000 tons of uranium per annum in phosphoric acid based fertilisers. Studies have also been carried out in France, Yugoslavia and India. In Israel, during the 1950's, a small plant was operated in Haifa by 'Chemical and Phosphates'. Uranium processes have also been developed by linking with the extraction processes at Arad. Currently there is almost no activity on this subject because there are no large phosphoric acid plants which would enable production to take place on a reasonable scale. Discussions are taking place about the installation of a plant for phosphoric acid production utilising the 'wet process', producing 200 to 250,000 tons P 2 O 5 per annum. It is necessary to combine these facilities with uranium production plant. (author)

  9. The geochemistry of acid rock drainage and estimating its ecological impact at a uranium mine in tropical Australia

    International Nuclear Information System (INIS)

    Brown, P.L.; Twining, J.R.; Bennett, J.W.; Comarmond, M.J.

    2000-01-01

    Geochemical kinetic modelling of the effluent chemistry from waste rock dumps at the Rum Jungle copper/uranium mine has been undertaken. The modelling examined the periods both before and after the installation of covers being placed on the dumps. Effluent from the waste rock dump migrates into the adjacent East Branch of the Finniss River and may induce ecological detriment. The model predicts pollutant loads that are significantly greater than that currently observed in the field. The observed reduction of pollutant loads after the cover was placed on the dump is attributed to a decrease in the rate of water infiltration due to the cover placement. It is estimated that a significant increase in pollutant loads is likely to occur Ca. 35 years after remediation. A computer program for ecological risk assessment, AQUARISK, has been developed and applied to evaluate the likelihood of biotic detriment due to exposure to pollutants from the site. Measured and modelled water quality data have been used in AQUARISK, in conjunction with national water quality guidelines and literature derived ecotoxicological data, to estimate the ecological risk for copper, this being a key pollutant. Both the present and past copper concentrations in the East Branch have a 100% risk of exceeding current regulatory criteria in addition to criteria derived from available dose-response data. The predicted increase in copper is unlikely to change these risks. However, the present reduction has led to an appreciable increase in the measured diversity of species at the site (from 8 to 50% implied) as also reflected in the AQUARISK estimate of increased tolerance (from 5 to 36% predicted). Modelled bioavailable copper concentrations will have a deleterious impact on the present degree of recovery and a return to the previous, unacceptably low, system diversity. To achieve a situation where 67% of species are likely to tolerate the effluent from the site, the average target copper concentration

  10. 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

  11. Classification algorithms using adaptive partitioning

    KAUST Repository

    Binev, Peter; Cohen, Albert; Dahmen, Wolfgang; DeVore, Ronald

    2014-01-01

    © 2014 Institute of Mathematical Statistics. Algorithms for binary classification based on adaptive tree partitioning are formulated and analyzed for both their risk performance and their friendliness to numerical implementation. The algorithms can be viewed as generating a set approximation to the Bayes set and thus fall into the general category of set estimators. In contrast with the most studied tree-based algorithms, which utilize piecewise constant approximation on the generated partition [IEEE Trans. Inform. Theory 52 (2006) 1335.1353; Mach. Learn. 66 (2007) 209.242], we consider decorated trees, which allow us to derive higher order methods. Convergence rates for these methods are derived in terms the parameter - of margin conditions and a rate s of best approximation of the Bayes set by decorated adaptive partitions. They can also be expressed in terms of the Besov smoothness β of the regression function that governs its approximability by piecewise polynomials on adaptive partition. The execution of the algorithms does not require knowledge of the smoothness or margin conditions. Besov smoothness conditions are weaker than the commonly used Holder conditions, which govern approximation by nonadaptive partitions, and therefore for a given regression function can result in a higher rate of convergence. This in turn mitigates the compatibility conflict between smoothness and margin parameters.

  12. Classification algorithms using adaptive partitioning

    KAUST Repository

    Binev, Peter

    2014-12-01

    © 2014 Institute of Mathematical Statistics. Algorithms for binary classification based on adaptive tree partitioning are formulated and analyzed for both their risk performance and their friendliness to numerical implementation. The algorithms can be viewed as generating a set approximation to the Bayes set and thus fall into the general category of set estimators. In contrast with the most studied tree-based algorithms, which utilize piecewise constant approximation on the generated partition [IEEE Trans. Inform. Theory 52 (2006) 1335.1353; Mach. Learn. 66 (2007) 209.242], we consider decorated trees, which allow us to derive higher order methods. Convergence rates for these methods are derived in terms the parameter - of margin conditions and a rate s of best approximation of the Bayes set by decorated adaptive partitions. They can also be expressed in terms of the Besov smoothness β of the regression function that governs its approximability by piecewise polynomials on adaptive partition. The execution of the algorithms does not require knowledge of the smoothness or margin conditions. Besov smoothness conditions are weaker than the commonly used Holder conditions, which govern approximation by nonadaptive partitions, and therefore for a given regression function can result in a higher rate of convergence. This in turn mitigates the compatibility conflict between smoothness and margin parameters.

  13. Use of air sampling data from uranium mills to estimate respiratory tract deposition rates for inhaled yellowcake

    International Nuclear Information System (INIS)

    Eidson, A.F.

    1982-01-01

    Uranium aerosols generated during normal yellowcake packaging operations were sampled at four uranium mills. Samplers located in the packaging area were operated before, during and after drums of dried yellowcake were filled and sealed. Mediar aerosol concentrations ranged from 0.04 μg U/l to 0.34 μg U/1 during the routine packaging operations at the four mills. The aerosols were heterogeneous and included a broad range of particle sizes. Both the concentrations and particle size distributions varied with time. Aerosol characteristics could often be related to individual packaging steps. Sampling of yellowcake by hand from a filled open drum to measure the yellowcake moisture content need not pose a unique hazard to the operator. The combined results show that appreciable amounts of airborne uranium would be expected to deposit in the nasopharyngeal compartment of the respiratory tract if inhaled by a worker not wearing respiratory protection

  14. 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

  15. 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.)

  16. Use of historical uranium air sampling data to estimate worker exposure potential to airborne radioactive particulate in a uranium processing facility.

    Science.gov (United States)

    Methner, M M; Feng, H A; Utterback, D F

    2001-12-01

    Historical industrial hygiene monitoring records from a uranium processing plant were collected and analyzed to characterize exposure potential to airborne radioactive particulate. More than 2,100 samples were collected during the period of 1954-1968. The data was organized by job title, plant number, and year of measurement. Laboratory analysis of air samples indicated a wide range of potential exposures to the alpha-emitting particulate. Logarithmic transformation of the data was necessary to approximate Gaussian distributions. Geometric Mean (GM) values were used as the measure of central tendency within years. GM values ranged from 23-49 disintegrations per minute per cubic meter of air sampled (dpm/m3) with the years 1963 and 1964 being significantly higher than other years (ANOVA: p exposure potential across plants, GM ranged from 20-68 dpm/m3, with plants 5 and 8 being significantly higher than the others (ANOVA: p Exposure potential for specific job titles across the plants varied widely. GM for clerks was the lowest (11 dpm/m3) while furnace operators were the highest (235 dpm/m3). Other job titles with potentially high exposures were chemical operators, forklift operators, machine operators, and furnace operators. This analysis indicates the magnitude and distributions of worker exposure to alpha-emitting airborne particulate. Additional analysis and epidemiologic studies are planned for this facility.

  17. Estimation of the uranium body radiation and the commitment dose from the results of the radio toxicological analysis of the urine

    International Nuclear Information System (INIS)

    Hirayama, Tomie

    1978-01-01

    The principal way of intake when individuals are accidentally exposed to the uranium compounds is the respiratory one. The deposition and clearance of the inhaled particles are influenced by the chemical, physical and biological characteristics of uranium. Kidney, lung and bones are the principal organs of deposition of absorbed uranium compounds, whose biological half-lives are approximately 6,62 ± 0,9 5 , 72,6 ± 2,2 and 322 ± 6 days respectively. An excretion function for the urinary pat radio toxicological urinalysis. This function is composed by three exponential terms, corresponding to the three organs of deposition. An estimation of the committed dose equivalent was carried out by utilizing: half-lives and the excreted, fraction suggested by I.C.R.F.; the average excreted fraction calculated from experimental data; half-life in the kidney and the fraction y u (1) excreted during the first day, experimentally determined; experimental half-lives in the kidney and lung and y u (1), and finally by utilizing all parameters of the individual, obtaining therefore, through this fifth determination a more reliable value of the committed dose equivalent in function of the particular metabolism of the individual. (author)

  18. Absorbed Dose Rate Due to Intake of Natural Radionuclides by Tilapia Fish (Tilapia nilotica,Linnaeus, 1758) Estimated Near Uranium Mining at Caetité, Bahia, Brazil

    Science.gov (United States)

    Pereira, Wagner de S.; Kelecom, Alphonse; Py Júnior, Delcy de Azevedo

    2008-08-01

    The uranium mining at Caetité (Uranium Concentrate Unit—URA) is in its operational phase. Aiming to estimate the radiological environmental impact of the URA, a monitoring program is underway. In order to preserve the biota of the deleterious effects from radiation and to act in a pro-active way as expected from a licensing body, the present work aims to use an environmental protection methodology based on the calculation of absorbed dose rate in biota. Thus, selected target organism was the Tilapia fish (Tilapia nilotica, Linnaeus, 1758) and the radionuclides were: uranium (U-238), thorium (Th-232), radium (Ra-226 and Ra-228) and lead (Pb-210). As, in Brazil there are no radiation exposure limits adopted for biota the value proposed by the Department of Energy (DOE) of the United States of 3.5×103 μGy y-1 has been used. The derived absorbed dose rate calculated for Tilapia was 2.51×100 μGy y-1, that is less than 0.1% of the dose limit established by DOE. The critical radionuclide was Ra-226, with 56% of the absorbed dose rate, followed by U-238 with 34% and Th-232 with 9%. This value of 0.1% of the limit allows to state that, in the operational conditions analyzed, natural radionuclides do not represent a radiological problem to biota.

  19. Absorbed Dose Rate Due to Intake of Natural Radionuclides by Tilapia Fish (Tilapia nilotica,Linnaeus, 1758) Estimated Near Uranium Mining at Caetite, Bahia, Brazil

    International Nuclear Information System (INIS)

    Pereira, Wagner de S; Kelecom, Alphonse; Azevedo Py Junior, Delcy de

    2008-01-01

    The uranium mining at Caetite (Uranium Concentrate Unit--URA) is in its operational phase. Aiming to estimate the radiological environmental impact of the URA, a monitoring program is underway. In order to preserve the biota of the deleterious effects from radiation and to act in a pro-active way as expected from a licensing body, the present work aims to use an environmental protection methodology based on the calculation of absorbed dose rate in biota. Thus, selected target organism was the Tilapia fish (Tilapia nilotica, Linnaeus, 1758) and the radionuclides were: uranium (U-238), thorium (Th-232), radium (Ra-226 and Ra-228) and lead (Pb-210). As, in Brazil there are no radiation exposure limits adopted for biota the value proposed by the Department of Energy (DOE) of the United States of 3.5x10 3 μGy y -1 has been used. The derived absorbed dose rate calculated for Tilapia was 2.51x10 0 μGy y -1 , that is less than 0.1% of the dose limit established by DOE. The critical radionuclide was Ra-226, with 56% of the absorbed dose rate, followed by U-238 with 34% and Th-232 with 9%. This value of 0.1% of the limit allows to state that, in the operational conditions analyzed, natural radionuclides do not represent a radiological problem to biota

  20. Uncertainties achievable for uranium isotope-amount ratios. Estimates based on the precision and accuracy of recent characterization measurements

    International Nuclear Information System (INIS)

    Mathew, K.J.; Essex, R.M.; Gradle, C.; Narayanan, U.

    2015-01-01

    Certified reference materials (CRMs) recently characterized by the NBL for isotope-amount ratios are: (i) CRM 112-A, Uranium (normal) Metal Assay and Isotopic Standard, (ii) CRM 115, Uranium (depleted) Metal Assay and Isotopic Standard, and (iii) CRM 116-A, Uranium (enriched) Metal Assay and Isotopic Standard. NBL also completed re-characterization of the isotope-amount ratios in CRM 125-A, Uranium (UO 2 ) Pellet Assay, Isotopic, and Radio-chronometric Standard. Three different TIMS analytical techniques were employed for the characterization analyses. The total evaporation technique was used for the major isotope-amount ratio measurement, the modified total evaporation technique was used for both the major and minor isotope-amount ratios, and minor isotope-amount ratios were also measured using a Conventional technique. Uncertainties for the characterization studies were calculated from the combined TIMS data sets following the ISO Guide to the expression of uncertainty in measurement. The uncertainty components for the isotope-amount ratio values are discussed. (author)

  1. Depleted uranium management alternatives

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-08-01

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

  2. Depleted uranium management alternatives

    International Nuclear Information System (INIS)

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

    1994-08-01

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

  3. 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

  4. 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)

  5. Uranium from seawater

    International Nuclear Information System (INIS)

    Gregg, D.; Folkendt, M.

    1982-01-01

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

  6. Laboratory Enrichment of Radioactive Assemblages and Estimation of Thorium and Uranium Radioactivity in Fractions Separated from Placer Sands in Southeast Bangladesh

    International Nuclear Information System (INIS)

    Sasaki, Takayuki; Rajib, Mohammad; Akiyoshi, Masafumi; Kobayashi, Taishi; Takagi, Ikuji; Fujii, Toshiyuki; Zaman, Md. Mashrur

    2015-01-01

    The present study reports the likely first attempt of separating radioactive minerals for estimation of activity concentration in the beach placer sands of Bangladesh. Several sand samples from heavy mineral deposits located at the south-eastern coastal belt of Bangladesh were processed to physically upgrade their radioactivity concentrations using plant and laboratory equipment. Following some modified flow procedure, individual fractions were separated and investigated using gamma-ray spectrometry and powder-XRD analysis. The radioactivity measurements indicated contributions of the thorium and uranium radioactive series and of 40 K. The maximum values of 232 Th and 238 U, estimated from the radioactivity of 208 Tl and 234 Th in secular equilibrium, were found to be 152,000 and 63,300 Bq/kg, respectively. The fraction of the moderately conductive part in electric separation contained thorium predominantly, while that of the non-conductive part was found to be uranium rich. The present arrangement of the pilot plant cascade and the fine tuning of setting parameters were found to be effective and economic separation process of the radioactive minerals from placer sands in Bangladesh. Probable radiological impacts and extraction potentiality of such radioactive materials are also discussed

  7. Laboratory Enrichment of Radioactive Assemblages and Estimation of Thorium and Uranium Radioactivity in Fractions Separated from Placer Sands in Southeast Bangladesh

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Takayuki, E-mail: sasaki@nucleng.kyoto-u.ac.jp [Kyoto University, Department of Nuclear Engineering (Japan); Rajib, Mohammad [Bangladesh Atomic Energy Commission, Nuclear Minerals Unit, Atomic Energy Research Establishment (Bangladesh); Akiyoshi, Masafumi; Kobayashi, Taishi; Takagi, Ikuji [Kyoto University, Department of Nuclear Engineering (Japan); Fujii, Toshiyuki [Kyoto University, Research Reactor Institute (Japan); Zaman, Md. Mashrur [Bangladesh Atomic Energy Commission, Nuclear Minerals Unit, Atomic Energy Research Establishment (Bangladesh)

    2015-06-15

    The present study reports the likely first attempt of separating radioactive minerals for estimation of activity concentration in the beach placer sands of Bangladesh. Several sand samples from heavy mineral deposits located at the south-eastern coastal belt of Bangladesh were processed to physically upgrade their radioactivity concentrations using plant and laboratory equipment. Following some modified flow procedure, individual fractions were separated and investigated using gamma-ray spectrometry and powder-XRD analysis. The radioactivity measurements indicated contributions of the thorium and uranium radioactive series and of {sup 40}K. The maximum values of {sup 232}Th and {sup 238}U, estimated from the radioactivity of {sup 208}Tl and {sup 234}Th in secular equilibrium, were found to be 152,000 and 63,300 Bq/kg, respectively. The fraction of the moderately conductive part in electric separation contained thorium predominantly, while that of the non-conductive part was found to be uranium rich. The present arrangement of the pilot plant cascade and the fine tuning of setting parameters were found to be effective and economic separation process of the radioactive minerals from placer sands in Bangladesh. Probable radiological impacts and extraction potentiality of such radioactive materials are also discussed.

  8. Uranium deposit research, 1983

    International Nuclear Information System (INIS)

    Ruzicka, V.; LeCheminant, G.M.

    1984-01-01

    Research on uranium deposits in Canada, conducted as a prerequisite for assessment of the Estimated Additional Resources of uranium, revealed that (a) the uranium-gold association in rudites of the Huronian Supergroup preferably occurs in the carbon layers; (b) chloritized ore at the Panel mine, Elliot Lake, Ontario, occurs locally in tectonically disturbed areas in the vicinity of diabase dykes; (c) mineralization in the Black Sturgeon Lake area, Ontario, formed from solutions in structural and lithological traps; (d) the Cigar Lake deposit, Saskatchewan, has two phases of mineralization: monomineralic and polymetallic; (e) mineralization of the JEB (Canoxy Ltd.) deposit is similar to that at McClean Lake; (f) the uranium-carbon assemblage was identified in the Claude deposit, Carswell Structure; and (g) the Otish Mountains area, Quebec, should be considered as a significant uranium-polymetallic metallogenic province

  9. One-year study of polycyclic aromatic compounds at an urban site in Grenoble (France): Seasonal variations, gas/particle partitioning and cancer risk estimation

    Energy Technology Data Exchange (ETDEWEB)

    Tomaz, Sophie [Institut National de l' Environnement industriel et des RISques (INERIS), Parc Technologique Alata BP2, 60550 Verneuil en Halatte (France); CNRS, EPOC, UMR 5805, F-33405 Talence Cedex (France); Université de Bordeaux, EPOC, UMR 5805, F-33405, Talence Cedex (France); Shahpoury, Pourya [Max Planck Institute for Chemistry, Multiphase Chemistry Department, Mainz (Germany); Jaffrezo, Jean-Luc [Laboratoire de Glaciologie et Géophysiques de l' Environnement (LGGE), Université de Grenoble-Alpes/CNRS, Grenoble (France); Lammel, Gerhard [Max Planck Institute for Chemistry, Multiphase Chemistry Department, Mainz (Germany); Masaryk University, Research Centre for Toxic Compounds in the Environment, Brno (Czech Republic); Perraudin, Emilie; Villenave, Eric [CNRS, EPOC, UMR 5805, F-33405 Talence Cedex (France); Université de Bordeaux, EPOC, UMR 5805, F-33405, Talence Cedex (France); Albinet, Alexandre, E-mail: alexandre.albinet@gmail.com [Institut National de l' Environnement industriel et des RISques (INERIS), Parc Technologique Alata BP2, 60550 Verneuil en Halatte (France)

    2016-09-15

    21 PAHs, 27 oxy-PAHs and 32 nitro-PAHs were measured every third day over a year in both gaseous (G) and particulate PM{sub 10} (P) phases in ambient air of Grenoble (France). Mean total concentrations (G + P) of PAHs and oxy-PAHs were in the same range and about 10 ng m{sup −3}. Nitro-PAHs were 50 to 100 times less concentrated averaging 100 pg m{sup −3}. Polycyclic aromatic compound (PAC) concentrations were 5 to 7 times higher in “cold” period (October to March) than in “warm” period (April to September). Seasonal variations may be explained by higher primary emissions from residential heating, especially biomass burning in “cold” season. Meteorological conditions and influence of the geomorphology around Grenoble, with the formation of thermal inversion layers leading to the stagnation of pollutants, were additional key parameters. Maximum individual PAC concentrations were observed during two PM{sub 10} pollution events in December and February–March. Chemical processes and secondary formation of oxy- and nitro-PAH were probably enhanced by the accumulation of the pollutants during these events. PAC gas/particle partitioning depended on compound molecular weight and vapour pressure. Gas/particle partitioning of oxy- and nitro-PAHs were evaluated using a multi-phase poly-parameter linear free energy relationship model. The PAC cancer risk was assessed using toxic equivalency factors available in the literature (19 PAHs, 10 nitro-PAHs and 1 oxy-PAH). Overall, particle-bound PACs contributed about 76% of the cancer risk. While PAHs accounted for most of the total PAC cancer risk, oxy- and nitro-PAHs could account for up to 24%. The risk quantification across substance classes is limited by toxicological data availability. - Highlights: • The most comprehensive study about PAH, nitro- and oxy-PAH in ambient air. • 80 species studied in gaseous and particle phases over a year at French urban site. • Concentration seasonality governed by

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

    International Nuclear Information System (INIS)

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

    1994-09-01

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

  11. Uranium in Canada

    International Nuclear Information System (INIS)

    1987-09-01

    Canadian uranium exploration and development efforts in 1985 and 1986 resulted in a significant increase in estimates of measured uranium resources. New discoveries have more than made up for production during 1985 and 1986, and for the elimination of some resources from the overall estimates, due to the sustained upward pressure on production costs and the stagnation of uranium prices in real terms. Canada possesses a large portion of the world's uranium resources that are of current economic interest and remains the major focus of inter-national uranium exploration activity. Expenditures for uranium exploration in Canada in 1985 and 1986 were $32 million and $33 million, respectively. Although much lower than the $130 million total reported for 1979, expenditures for 1987 are forecast to increase. Exploration and surface development drilling in 1985 and 1986 were reported to be 183 000 m and 165σ2 000 m, respectively, 85 per cent of which was in Saskatchewan. Canada has maintained its position as the world's leading producer and exporter of uranium. By the year 2000, Canada's annual uranium requirements will be about 2 100 tU. Canada's known uranium resources are more than sufficient to meet the 30-year fuel requirements of those reactors in Canada that are either in operation now or expected to be in service by the late 1990s. A substantial portion of Canada's identified uranium resources is thus surplus to Canadian needs and available for export. Annual sales currently approach $1 billion, of which exports account for 85 per cent. Forward domestic and export contract commitments totalled 73 000 tU and 62 000 tU, respectively, as of early 1987

  12. An Australian view of the uranium market

    International Nuclear Information System (INIS)

    Lloyd, B.

    1978-01-01

    The subject is covered in sections, entitled as shown. Numerical data are indicated in parenthesis. Introduction (principal Australian uranium deposits, possible Australian production, estimates of world-wide uranium resources and production, estimates of world-wide uranium requirements); Australian marketing policy; commercial considerations; uncertainties affecting the industry, including unnecessary and undesirable government involvement, and supply and demand. (U.K.)

  13. Uranium resource assessments

    International Nuclear Information System (INIS)

    1981-01-01

    The objective of this investigation is to examine what is generally known about uranium resources, what is subject to conjecture, how well do the explorers themselves understand the occurrence of uranium, and who are the various participants in the exploration process. From this we hope to reach a better understanding of the quality of uranium resource estimates as well as the nature of the exploration process. The underlying questions will remain unanswered. But given an inability to estimate precisely our uranium resources, how much do we really need to know. To answer this latter question, the various Department of Energy needs for uranium resource estimates are examined. This allows consideration of whether or not given the absence of more complete long-term supply data and the associated problems of uranium deliverability for the electric utility industry, we are now threatened with nuclear power plants eventually standing idle due to an unanticipated lack of fuel for their reactors. Obviously this is of some consequence to the government and energy consuming public. The report is organized into four parts. Section I evaluates the uranium resource data base and the various methodologies of resource assessment. Part II describes the manner in which a private company goes about exploring for uranium and the nature of its internal need for resource information. Part III examines the structure of the industry for the purpose of determining the character of the industry with respect to resource development. Part IV arrives at conclusions about the emerging pattern of industrial behavior with respect to uranium supply and the implications this has for coping with national energy issues

  14. Use of geoprocessing tools in uranium mining: volume estimation of sterile piles from the Osamu Utsumi Mine of INB / Caldas

    International Nuclear Information System (INIS)

    Ferreira, A.M.; Menezes, P.H.B.J.; Alberti, H.L.C.; Silva, N.C. da; Goda, R.T.

    2017-01-01

    The determination of the volumes of the sterile piles generated in the uranium mining and their respective characterization is of extreme importance for the management of mining wastes and future decommissioning actions of a nuclear facility. With the development of information technology, it becomes possible to simulate different scenarios in a computational environment, being able to store, represent and process data from existing information. In the industrial mining context, the sterile is represented with rocky materials of different granulometries and with ore content below the cut content determined by the industrial process. In this sense, the present work has the objective of calculating the volume of the sterile stacks of the Osamu Utsumi uranium mine of INB - Nuclear Industries of Brazil / Caldas. The MOU was officially inaugurated in 1977 and operated until 1995, where 1,200 tons of U 2 O 3 were produced generating about 94.5 x 106 tons of sterile material containing low levels of radioactive material and pyrite. The methodology for the development of this work initially involves integration approaches between the Geographic Information System (GIS) and terrain modeling for the sterile piles called BF4 and BF8. The results obtained were compared with the existing literature, translating the importance of GIS as a tool in the management of wastes

  15. Estimation of ventilation rate in uranium or thorium handling laboratories using short-lived thoron daughter activity

    International Nuclear Information System (INIS)

    Shivade, R.K.; Deshpande, S.B.

    2016-01-01

    Natural uranium in oxide form is used as fuel in the Indian PHWR. Natural 238 U fuel contains 232 Th as an impurity to the extent of 50 - 60 ppm. This thorium impurity is converted to 232 U in reactor during irradiation. 232 U is converted to 224 Ra by alpha decays, 224 Ra further decays to 220 Rn by alpha decays. 220 Rn decays to stable 208 Pb by emitting alpha, beta particles and gamma rays. 220 Rn is inert gas but its daughter products are in particulate form. Effective half-life of Tn decay series is 10.6 hrs and four days are required to reduce the air borne activity concentration to negligible level on a filter paper sample. Uranium or thorium is handled remotely in the glove boxes with proper shielding. Glove boxes are under optimum negative pressure. Exhausts from glove boxes are connected to stack with proper filtration. Amber ares of the Lab is also supplied with conditioned air supply for human comfort and to keep the atmospheric thoron daughter concentration under control. Even after using proper engineering safety features, thoron that is in the gaseous form can came out from glove boxes due to holes on the neoprene gloves of micro or nano dimensions. Probability of thoron gas leakage is more during bagging out or bagging in operations. This gives rise to thoron daughter activity in the working atmosphere of Lab constantly and workers should be protected adequately

  16. U for uranium

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    The Beisa Mine is unique in South Africa - it is the only underground mine with uranium as its main product and gold as a by-product. At the rate of 1,2 Mt/a, the life of Beisa is estimated on 26 years. Beisa's metallurgical plant is designed to handle initially a monthly throughput of 100 000t of ore, from which uranium, gold and silver will be extracted

  17. Determination of transfer factors of uranium, thorium, radium and lead from soil to agricultural product in Japan for estimating internal radiation dose through ingestion

    International Nuclear Information System (INIS)

    Sasaki, Tomozo; Tashiro, Yoshikazu; Fujinaga, Hideshi; Ishii, Tomoaki; Gunji, Yasuyoshi

    2002-01-01

    The transfer factors (TFs) of uranium (U), thorium (Th), radium (Ra) and lead (Pb) from soil to agricultural products were determined in order to estimate the internal radiation dose to the human body through ingestion. Samples of rice, potato, onion, cabbage, mandarin orange, spinach, apple and soil were collected from various districts in Japan. After appropriate pretreatment of the samples, concentrations in the sample solutions were measured by Inductively coupled plasma-mass spectrometry (ICP-MS) (for U, Th and Pb) and liquid scintillation counter (for Ra). It was recognized that TFs were 4.9 x 10 -6 (apple) and 3.6 x 10 -4 (spinach) for U, 2.8 x 10 -6 (apple) and 2.3 x 10 -4 (spinach) for Th, and 4.0 x 10 -3 (hulled rice), 7.0 x 10 -5 (onion) and 5.0 x 10 -3 (hulled rice) for Pb. The TF of Ra, however, was not determined due to detection limitations. TF values obtained in the present study range from the same order of magnitude to 1/100 compared to the data in Technical Report Series No.364 (TRS364) as reported by IAEA. It was revealed that the internal radiation dose caused by the intake of uranium series radioactive nuclides through agricultural food ingestion was 16 μSv/y, where Pb was the most contributory nuclide. (author)

  18. Absorbed dose rate due to intake of natural radionuclides by Tilapia fish (Tilapia nilotica, Linnaeus, 1758) estimated near uranium anomaly at Santa Quiteria, Ceara, Brazil

    International Nuclear Information System (INIS)

    Pereira, Wagner de; Kelecom, Alphonse; Py Junior, Delcy de Azevedo

    2007-01-01

    The uranium mining at Santa Quiteria (Santa Quiteria Unit - USQ) is in its environmental licensing phase. Aiming to estimate the radiological environmental impact of the USQ, a monitoring program is underway. However, radioprotection of biota is not explicitly mentioned in Brazilian norms. In order to preserve the biota of the deleterious effects from radiation and to behave in a pro-active way as expected by licensing organs, the present work aims to use an environmental protection methodology, based on the calculation of absorbed dose rate in biota. Thus, selected biomarker was the fish tilapia (Tilapia nilotica, Linnaeus, 1758) and the radionuclides were: uranium (U-238), thorium (Th-232), radium (Ra-226 and Ra-228) and lead (Pb-210). Since there are no exposition limits for biota, in Brazil, the value proposed by the Department of Energy (DOE) of the United States of 3.5 x 10 3 μGy/y has been used. The derived absorbed dose rate calculated for tilapia was 2.76 x 10 0 μGy/y, that is less than 0.1 % of the limit established by DOE. The critical radionuclide was U-238, with 99% of the absorbed dose rate. This value of 0.1% of the limit allows to state that in pre-operational conditions analyzed natural radionuclides do not represent a radiological problem to the biota. (author)

  19. Absorbed dose rate due to intake of natural radionuclides by Tilapia fish (Tilapia nilotica, Linnaeus, 1758) estimated near uranium anomaly at Santa Quiteria, Ceara, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Wagner de [Industrias Nucleares do Brasil S.A. (INB), Pocos de Caldas, MG (Brazil). Coordenacao de Protecao Radiologica. Unidade de Tratamento de Minerios], E-mail: wspereira@inb.gov.br; Kelecom, Alphonse [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Programa de Pos-graduacao em Ciencia Ambiental; Py Junior, Delcy de Azevedo [Industrias Nucleares do Brasil S.A. (INB), Caetite, BA (Brazil). Coordenacao de Protecao Radiologica. Unidade de Concentrado de Uranio], E-mail: Delcy@inb.gov.br

    2007-07-01

    The uranium mining at Santa Quiteria (Santa Quiteria Unit - USQ) is in its environmental licensing phase. Aiming to estimate the radiological environmental impact of the USQ, a monitoring program is underway. However, radioprotection of biota is not explicitly mentioned in Brazilian norms. In order to preserve the biota of the deleterious effects from radiation and to behave in a pro-active way as expected by licensing organs, the present work aims to use an environmental protection methodology, based on the calculation of absorbed dose rate in biota. Thus, selected biomarker was the fish tilapia (Tilapia nilotica, Linnaeus, 1758) and the radionuclides were: uranium (U-238), thorium (Th-232), radium (Ra-226 and Ra-228) and lead (Pb-210). Since there are no exposition limits for biota, in Brazil, the value proposed by the Department of Energy (DOE) of the United States of 3.5 x 10{sup 3} {mu}Gy/y has been used. The derived absorbed dose rate calculated for tilapia was 2.76 x 10{sup 0} {mu}Gy/y, that is less than 0.1 % of the limit established by DOE. The critical radionuclide was U-238, with 99% of the absorbed dose rate. This value of 0.1% of the limit allows to state that in pre-operational conditions analyzed natural radionuclides do not represent a radiological problem to the biota. (author)

  20. Biotransformation of dichlorodiphenyltrichloroethane in the benthic polychaete, Nereis succinea: quantitative estimation by analyzing the partitioning of chemicals between gut fluid and lipid.

    Science.gov (United States)

    Wang, Fei; Pei, Yuan-yuan; You, Jing

    2015-02-01

    Biotransformation plays an important role in the bioaccumulation and toxicity of a chemical in biota. Dichlorodiphenyltrichloroethane (DDT) commonly co-occurs with its metabolites (dichlorodiphenyldichloroethane [DDD] and dichlorodiphenyldichloroethylene [DDE]), in the environment; thus it is a challenge to accurately quantify the biotransformation rates of DDT and distinguish the sources of the accumulated metabolites in an organism. The present study describes a method developed to quantitatively analyze the biotransformation of p,p'-DDT in the benthic polychaete, Nereis succinea. The lugworms were exposed to sediments spiked with DDT at various concentrations for 28 d. Degradation of DDT to DDD and DDE occurred in sediments during the aging period, and approximately two-thirds of the DDT remained in the sediment. To calculate the biotransformation rates, residues of individual compounds measured in the bioaccumulation testing (after biotransformation) were compared with residues predicted by analyzing the partitioning of the parent and metabolite compounds between gut fluid and tissue lipid (before biotransformation). The results suggest that sediment ingestion rates decreased when DDT concentrations in sediment increased. Extensive biotransformation of DDT occurred in N. succinea, with 86% of DDT being metabolized to DDD and biotransformation, and the remaining 30% was from direct uptake of sediment-associated DDD. In addition, the biotransformation was not dependent on bulk sediment concentrations, but rather on bioaccessible concentrations of the chemicals in sediment, which were quantified by gut fluid extraction. The newly established method improved the accuracy of prediction of the bioaccumulation and toxicity of DDTs. © 2014 SETAC.

  1. Estimating fate and transport of multiple contaminants in the vadose zone using a multi-layered soil column and three-phase equilibrium partitioning model

    International Nuclear Information System (INIS)

    Rucker, Gregory G.

    2007-01-01

    Soils at waste sites must be evaluated for the potential of residual soil contamination to leach and migrate to the groundwater beneath the disposal area. If migration to the aquifer occurs, contaminants can travel vast distances and pollute drinking water wells, thus exposing human receptors to harmful levels of toxins and carcinogens. To prevent groundwater contamination, a contaminant fate and transport analysis is necessary to assess the migration potential of residual soil contaminants. This type of migration analysis is usually performed using a vadose zone model to account for complex geotechnical and chemical variables including: decay processes, infiltration rate, soil properties, vadose zone thickness, and chemical behavior. The distinct advantage of using a complex model is that less restrictive, but still protective, soil threshold levels may be determined avoiding the unnecessary and costly remediation of marginally contaminated soils. However, the disadvantage of such modeling is the additional cost for data collection and labor required to apply these models. In order to allay these higher costs and to achieve a less restrictive but still protective clean-up level, a multiple contaminant and multi layered soil column equilibrium partitioning model was developed which is faster, simpler and less expensive to use. (authors)

  2. Australian uranium resources

    International Nuclear Information System (INIS)

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

    1987-01-01

    Australia's uranium resources amount to 29% of the WOCA countries (world outside centrally-planned-economies areas) low-cost Reasonably Assured Resources and 28% of the WOCA countries low-cost Estimated Additional Resources. As at 1 January 1986, the Bureau of Mineral Resources estimated Australia's uranium resources as: (1) Cost range to US$80/kg U -Reasonably Assured Resources, 465 000 t U; Estimated Additional Resources, 256 000 t U; (2) Cost range US$80-130/kg U -Reasonably Assured Resources, 56 000 t U; Estimated Additional Resources, 127 000 t U. Most resources are contained in Proterozoic unconformity-related deposits in the Alligator Rivers uranium field in the Northern Territory (Jabiluka, Ranger, Koongarra, Nabarlek deposits) and the Proterozoic stratabound deposit at Olympic Dam on the Stuart Shelf in South Australia

  3. Parameterization of the 3-PG model for Pinus elliottii stands using alternative methods to estimate fertility rating, biomass partitioning and canopy closure

    Science.gov (United States)

    Carlos A. Gonzalez-Benecke; Eric J. Jokela; Wendell P. Cropper; Rosvel Bracho; Daniel J. Leduc

    2014-01-01

    The forest simulation model, 3-PG, has been widely applied as a useful tool for predicting growth of forest species in many countries. The model has the capability to estimate the effects of management, climate and site characteristics on many stand attributes using easily available data. Currently, there is an increasing interest in estimating biomass and assessing...

  4. Incentives for partitioning, revisited

    International Nuclear Information System (INIS)

    Cloninger, M.O.

    1980-01-01

    The incentives for separating and eliminating various elements from radioactive waste prior to final geologic disposal were investigated. Exposure pathways to humans were defined, and potential radiation doses to an individual living within the region of influence of the underground storage site were calculated. The assumed radionuclide source was 1/5 of the accumulated high-level waste from the US nuclear power economy through the year 2000. The repository containing the waste was assumed to be located in a reference salt site geology. The study required numerous assumptions concerning the transport of radioactivity from the geologic storage site to man. The assumptions used maximized the estimated potential radiation doses, particularly in the case of the intrusion water well scenario, where hydrologic flow field dispersion effects were ignored. Thus, incentives for removing elements from the waste tended to be maximized. Incentives were also maximized by assuming that elements removed from the waste could be eliminated from the earth without risk. The results of the study indicate that for reasonable disposal conditions, incentives for partitioning any elements from the waste in order to minimize the risk to humans are marginal at best

  5. Recovery of uranium from seawater

    International Nuclear Information System (INIS)

    Hirotsu, Takahiro; Takagi, Norio; Katoh, Shunsaku

    1995-01-01

    Present status of the development of chelating adsorbents for the recovery of uranium from seawater is outlined with emphasis on the research by the author. Uranium is estimated to exist as stable tri (carbonate) uranylate (6) ion in seawater in a very low concentration. The adsorbent for uranium from seawater in a very low concentration. The adsorbent for uranium from seawater should have high selectivity and affinity for uranium around pH 8. The required characteristics for uranium adsorbent are examined. Various chelating adsorbents have been proposed for the uranium adsorbent and their structures are discussed. Amidoxime type adsorbents have the highest adsorbing power for uranium among the adsorbents hitherto developed and fibrous amidoxime adsorbents are most promising for the practical application. Synthesis, structure and suitable shape of the amidoxime adsorbents are discussed. Uranium adsorption behavior and the amount of saturated adsorption are examined theoretically based on the complexation of an amidoxime monomer and the formula for the adsorption equiliburium is derived. The adsorption and recovery process for uranium from seawater is composed of adsorption, desorption, separation and concentration and finally, uranium is recovered as the yellow cake. A floating body mooring system is proposed by Nobukawa. (T.H.)

  6. The Estimation of Internal Contamination with Uranium from Urine Analysis Results; Evaluation de la Contamination Interne par l'Uranium a Partir des Resultats de l'Analyse d'Urines; 041e 0426 0414 ; Evaluacion de la Contaminacion Interna con Uranio a Partir de los Resultados del Analisis de Orina

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, S. [Authority Health and Safety Branch, Radiological Protection Division, United Kingdom Atomic Energy Authority, Harwell, Berks. (United Kingdom)

    1964-11-15

    The most common cause of internal contamination with uranium is inhalation of uranium dust. Soluble uranium compounds are rapidly absorbed from the lungs, and most of the uranium entering the circulation is rapidly excreted in the urine. The intake of soluble uranium at work can be estimated from the uranium content of urine samples taken immediately afterwards. It is a special feature of soluble compounds of natural uranium that the primary consideration is not radiological but toxicological due to chemical effects of uranium deposited in the kidneys. Some uranium is also deposited in the skeleton, but the irradiation of bone is less critical, in the case of natural uranium, than the toxicity to kidney. For soluble compounds of highly-enriched uranium with its high specific activity, the primary concern is radiological; the chemical effects on the kidneys are less limiting than the irradiation of bone, which thus becomes the critical organ. In this case, it is better to attempt to assess the retained body burden rather than the intake of uranium. This may be done by analysing urine samples taken not immediately after exposure but when some time has elapsed. Samples taken after a holiday are probably the best material available in practice, but it may be necessary to accept samples after only a week-end of removal from uranium work. (author) [French] Evaluation de la contamination interne par l'uranium a partir des resultats de l'analyse d'urines. La cause la plus frequente de contamination interne par l'uranium est l'inhalation de poussieres d'uranium. Les composes solubles de l'uranium sont rapidement absorbes au niveau des poumons et la plus grande partie de l'uranium qui passe dans le sang est rapidement rejetee avec l'urine. La quantite d'uranium soluble actif qui est absorbee peut etre determinee a partir de la teneur en uranium d'echantillons preleves immediatement apres. Les composes solubles de l'uranium naturel ont une particularite en ce sens que la

  7. Uranium tipped ammunition

    International Nuclear Information System (INIS)

    Roche, P.

    1993-01-01

    During the uranium enrichment process required to make nuclear weapons or fuel, the concentration of the 'fissile' U-235 isotope has to be increased. What is left, depleted uranium, is about half as radioactive as natural uranium, but very dense and extremely hard. It is used in armour piercing shells. External radiation levels from depleted uranium (DU) are low. However DU is about as toxic as lead and could be harmful to the kidneys if eaten or inhaled. It is estimated that between 40 and 300 tonnes of depleted uranium were left behind by the Allied armies after the Gulf war. The biggest hazard would be from depleted uranium shells which have hit Iraqui armoured vehicles and the resulting dust inhaled. There is a possible link between depleted uranium shells and an illness known as 'Desert Storm Syndrome' occurring in some Gulf war veterans. As these shells are a toxic and radioactive hazard to health and the environment their use and testing should be stopped because of the risks to troops and those living near test firing ranges. (UK)

  8. Uranium and the generation of power - the South African perspective

    International Nuclear Information System (INIS)

    Von Backstrom, J.W.

    1975-01-01

    The author examines uranium requirements, uranium production capacity and uranium reserves in the light of estimated energy forecasts for South Africa and the western world. The impact of breeder reactors, plutonium and uranium enrichment is also considered. He then deals with the South African uranium situation and the exploration that is currently under way, and makes some recommendations. These are followed by a list of characteristics and criteria that have a bearing on uranium mineralisation in various formations in South Africa

  9. Fossile fuel and uranium resources

    International Nuclear Information System (INIS)

    Gorkum, A.A. van.

    1975-01-01

    The world's resources of coal, lignite, oil, natural gas, shale oil and uranium are reviewed. These quantities depend on the prices which make new resources exploitable. Uranium resources are given exclusively for the USSR, Eastern Europe and China. Their value in terms of energy depends heavily on the reactor type used. All figures given are estimated to be conservative

  10. World uranium production in 1995

    International Nuclear Information System (INIS)

    Anon.

    1996-01-01

    For the first time since the political and economic opening of the former Soviet Union and Eastern Europe, world uranium production actually increased in 1995. Preliminary estimates for 1996 continue this trend, indicating additional (if slight) production increases over 1995 levels. Natural uranium production increased by about 5% in 1995 to 34,218 tons uranium or 89 Mlbs U3O8. This is an increase of approximately 1700 tons of uranium or 4.3 Mlbs of U3O8 over the updated 1994 quantities. Data is presented for each of the major uranium producing countries, for each of the world's largest uranium mines, for each of the world's largest corporate producers, and for major regions of the world

  11. 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

  12. Lake Michigan Diversion Accounting land cover change estimation by use of the National Land Cover Dataset and raingage network partitioning analysis

    Science.gov (United States)

    Sharpe, Jennifer B.; Soong, David T.

    2015-01-01

    The U.S. Army Corps of Engineers (USACE), Chicago District, is responsible for monitoring and computation of the quantity of Lake Michigan water diverted by the State of Illinois. As part of this effort, the USACE uses the Hydrological Simulation Program–FORTRAN (HSPF) with measured meteorological data inputs to estimate runoff from the Lake Michigan diversion special contributing areas (SCAs), the North Branch Chicago River above Niles and the Little Calumet River above South Holland gaged basins, and the Lower Des Plaines and the Calumet ungaged that historically drained to Lake Michigan. These simulated runoffs are used for estimating the total runoff component from the diverted Lake Michigan watershed, which is accountable to the total diversion by the State of Illinois. The runoff is simulated from three interpreted land cover types in the HSPF models: impervious, grass, and forest. The three land cover data types currently in use were derived from aerial photographs acquired in the early 1990s.

  13. Uranium 2003 resources, production and demand

    CERN Document Server

    Organisation for Economic Cooperation and Development. Paris

    2004-01-01

    Uranium 2003: Resources, Production and Demand paints a detailed statistical profile of the world uranium industry in the areas of exploration, resource estimates, production and reactor-related requirements. It provides substantial new information from all major uranium production centres in Africa, Australia, Eastern Europe and North America and for the first time, a report for Turkmenistan. Also included are international expert analyses and projections of nuclear generating capacity and reactor-related uranium requirements through 2020.

  14. 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

  15. 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.)

  16. 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)

  17. 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?

  18. Empirical Bayes Approaches to Multivariate Fuzzy Partitions.

    Science.gov (United States)

    Woodbury, Max A.; Manton, Kenneth G.

    1991-01-01

    An empirical Bayes-maximum likelihood estimation procedure is presented for the application of fuzzy partition models in describing high dimensional discrete response data. The model describes individuals in terms of partial membership in multiple latent categories that represent bounded discrete spaces. (SLD)

  19. Australia's uranium export potential

    International Nuclear Information System (INIS)

    Mosher, D.V.

    1981-01-01

    During the period 1954-71 in Australia approximately 9000 MT of U 3 O 8 was produced from five separate localities. Of this, 7000 MT was exported to the United Kingdom and United States and the balance stockpiled by the Australian Atomic Energy Commission (AAEC). Australia's uranium ore reserves occur in eight deposits in three states and the Northern Territory. However, 83% of Australia's reserves are contained in four deposits in lower Proterozoic rocks in the East Alligator River region of the Northern Territory. The AAEC has calculated Australia's recoverable uranium reserves by eliminating estimated losses during the mining and milling of the ores. AAEC has estimated reasonably assured resources of 289,000 MT of uranium at a recovery cost of less than US$80 per kilogram uranium. The companies have collectively announced a larger ore reserve than the Australian Atomic Energy Commission. This difference is a result of the companies adopting different ore reserve categories. On August 25, 1977, the federal government announced that Australia would develop its uranium resources subject to stringent environmental controls, recognition of Aboriginal Land Rights, and international safeguards. Australian uranium production should gradually increase from 1981 onward, growing to 10,000 to 15,000 MT by 1985-86. Further increases in capacity may emerge during the second half of the 1980s when expansion plans are implemented. Exploration for uranium has not been intensive due to delays in developing the existing deposits. It is likely that present reserves can be substantially upgraded if more exploration is carried out. 6 figures, 3 tables

  20. Uranium in Canada

    International Nuclear Information System (INIS)

    1989-01-01

    In 1988 Canada's five uranium producers reported output of concentrate containing a record 12,470 metric tons of uranium (tU), or about one third of total Western world production. Shipments exceeded 13,200 tU, valued at $Cdn 1.1 billion. Most of Canada's uranium output is available for export for peaceful purposes, as domestic requirements represent about 15 percent of production. The six uranium marketers signed new sales contracts for over 11,000 tU, mostly destined for the United States. Annual exports peaked in 1987 at 12,790 tU, falling back to 10,430 tU in 1988. Forward domestic and export contract commitments were more than 70,000 tU and 60,000 tU, respectively, as of early 1989. The uranium industry in Canada was restructured and consolidated by merger and acquisition, including the formation of Cameco. Three uranium projects were also advanced. The Athabasca Basin is the primary target for the discovery of high-grade low-cost uranium deposits. Discovery of new reserves in 1987 and 1988 did not fully replace the record output over the two-year period. The estimate of overall resources as of January 1989 was down by 4 percent from January 1987 to a total (measured, indicated and inferred) of 544,000 tU. Exploration expenditures reached $Cdn 37 million in 1987 and $59 million in 1988, due largely to the test mining programs at the Cigar Lake and Midwest projects in Saskatchewan. Spot market prices fell to all-time lows from 1987 to mid-1989, and there is little sign of relief. Canadian uranium production capability could fall below 12,000 tU before the late 1990s; however, should market conditions warrant output could be increased beyond 15,000 tU. Canada's known uranium resources are more than sufficient to meet the 30-year fuel requirements of those reactors in Canada that are now or are expected to be in service by the late 1990s. There is significant potential for discovering additional uranium resources. Canada's uranium production is equivalent, in

  1. Plane partition vesicles

    International Nuclear Information System (INIS)

    Rensburg, E J Janse van; Ma, J

    2006-01-01

    We examine partitions and their natural three-dimensional generalizations, plane partitions, as models of vesicles undergoing an inflation-deflation transition. The phase diagrams of these models include a critical point corresponding to an inflation-deflation transition, and exhibits multicritical scaling in the vicinity of a multicritical point located elsewhere on the critical curve. We determine the locations of the multicritical points by analysing the generating functions using analytic and numerical means. In addition, we determine the numerical values of the multicritical scaling exponents associated with the multicritical scaling regimes in these models

  2. Matrix string partition function

    CERN Document Server

    Kostov, Ivan K; Kostov, Ivan K.; Vanhove, Pierre

    1998-01-01

    We evaluate quasiclassically the Ramond partition function of Euclidean D=10 U(N) super Yang-Mills theory reduced to a two-dimensional torus. The result can be interpreted in terms of free strings wrapping the space-time torus, as expected from the point of view of Matrix string theory. We demonstrate that, when extrapolated to the ultraviolet limit (small area of the torus), the quasiclassical expressions reproduce exactly the recently obtained expression for the partition of the completely reduced SYM theory, including the overall numerical factor. This is an evidence that our quasiclassical calculation might be exact.

  3. 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

  4. Development of long-lived radionuclide partitioning technology

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Jae Hyung; Lee, Eil Hee; Kim, Kwang Wook; Yang, Han Beom; Chung, Dong Yong; Lim, Jae Kwan; Shin, Young Jun; Kim, Heung Ho; Kown, Sun Gil; Kim, Young Hwan; Hwang, Doo Seung

    1996-07-01

    This study has been focused on the development of unit processes for partitioning in the 1st stage, and experimentally carried out to examine the separation characteristics and operation conditions on the following unit processes. (1) Removal of a small amount of uranium by extraction with TBP, (2) Removal of Zr and Mo and destruction of nitric acid by uranium by denitration with formic acid, (3) Co-precipitation of Am, Np and RE oxalic acid, (4) Dissolution and destruction of oxalate by hydrogen peroxide, (5) Co-extraction of Am, Np and RE by nitric acid, (8) Back-extraction of Np by oxalic acid, (9) Adsorption and elution of Cs and Sr by zeolite, and (10) Advanced separation of radionuclide by electrochemical REDOX method. The results obtained from each unit process will be use as the basic materials for the establishment of optimal partitioning and design of process equipment. (author). 46 refs., 54 tabs., 222 figs.

  5. Developments in uranium in 1986

    International Nuclear Information System (INIS)

    Chenoweth, W.L.

    1987-01-01

    Imported uranium and low prices continued to plague the domestic uranium industry and, as a result, the Secretary of Energy declared the domestic industry to be nonviable for the second straight year. Uranium exploration expenditures in the US declined for the eighth consecutive year. In 1986, an estimated $19 million was spent on uranium exploration, including 1.9 million ft of surface drilling. This drilling was done mainly in producing areas and in areas of recent discoveries. Production of uranium concentrate increased in 1986, when 13.8 million lb of uranium oxide (U 3 O 8 ) were produced, a 22% increase over 1985. Uranium produced as the result of solution mining and as the by-product of phosphoric acid production accounted for about 37% of the total production in the US. At the end of 1986, only 6 uranium mills were operating in the US. Canada continued to dominate the world market. The development under way at the huge Olympic Dam deposit in Australia will increase that country's production. US uranium production is expected to show a small decrease in 1987. 3 figures, 2 tables

  6. Bio-precipitation of uranium by two bacterial isolates recovered from extreme environments as estimated by potentiometric titration, TEM and X-ray absorption spectroscopic analyses

    Energy Technology Data Exchange (ETDEWEB)

    Merroun, Mohamed L., E-mail: merroun@ugr.es [Institute of Radiochemistry, Helmholtz Centre Dresden-Rossendorf, Dresden (Germany); Departamento de Microbiologia, Universidad de Granada, Campus Fuentenueva s/n 18071, Granada (Spain); Nedelkova, Marta [Institute of Radiochemistry, Helmholtz Centre Dresden-Rossendorf, Dresden (Germany); Ojeda, Jesus J. [Cell-Mineral Interface Research Programme, Kroto Research Institute, University of Sheffield, Broad Lane, Sheffield S3 7HQ (United Kingdom); Experimental Techniques Centre, Brunel University, Uxbridge, Middlesex UB8 3PH (United Kingdom); Reitz, Thomas [Institute of Radiochemistry, Helmholtz Centre Dresden-Rossendorf, Dresden (Germany); Fernandez, Margarita Lopez; Arias, Jose M. [Departamento de Microbiologia, Universidad de Granada, Campus Fuentenueva s/n 18071, Granada (Spain); Romero-Gonzalez, Maria [Cell-Mineral Interface Research Programme, Kroto Research Institute, University of Sheffield, Broad Lane, Sheffield S3 7HQ (United Kingdom); Selenska-Pobell, Sonja [Institute of Radiochemistry, Helmholtz Centre Dresden-Rossendorf, Dresden (Germany)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer Precipitation of uranium as U phosphates by natural bacterial isolates. Black-Right-Pointing-Pointer The uranium biomineralization involves the activity of acidic phosphatase. Black-Right-Pointing-Pointer Uranium bioremediation could be achieved via the biomineralization of U(VI) in phosphate minerals. - Abstract: This work describes the mechanisms of uranium biomineralization at acidic conditions by Bacillus sphaericus JG-7B and Sphingomonas sp. S15-S1 both recovered from extreme environments. The U-bacterial interaction experiments were performed at low pH values (2.0-4.5) where the uranium aqueous speciation is dominated by highly mobile uranyl ions. X-ray absorption spectroscopy (XAS) showed that the cells of the studied strains precipitated uranium at pH 3.0 and 4.5 as a uranium phosphate mineral phase belonging to the meta-autunite group. Transmission electron microscopic (TEM) analyses showed strain-specific localization of the uranium precipitates. In the case of B. sphaericus JG-7B, the U(VI) precipitate was bound to the cell wall. Whereas for Sphingomonas sp. S15-S1, the U(VI) precipitates were observed both on the cell surface and intracellularly. The observed U(VI) biomineralization was associated with the activity of indigenous acid phosphatase detected at these pH values in the absence of an organic phosphate substrate. The biomineralization of uranium was not observed at pH 2.0, and U(VI) formed complexes with organophosphate ligands from the cells. This study increases the number of bacterial strains that have been demonstrated to precipitate uranium phosphates at acidic conditions via the activity of acid phosphatase.

  7. 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

  8. Bacterial diversity in a soil sample from Uranium mining waste pile as estimated via a culture-independent 16S rDNA approach

    International Nuclear Information System (INIS)

    Satchanska, G.; Golovinsky, E.; Selenska-Pobell, S.

    2004-01-01

    Bacterial diversity was studied in a soil sample collected from a uranium mining waste pile situated near the town of Johanngeorgenstadt, Germany. As estimated by ICP-MS analysis the studied sample was highly contaminated with Fe, Al, Mn, Zn, As, Pb and U. The 16S rDNA retrieval, applied in this study, demonstrated that more than the half of the clones of the constructed 16S rDNA library were represented by individual RFLP profiles. This indicates that the composition of the bacterial community in the sample was very complex. However, several 16S rDNA RFLP groups were found to be predominant and they were subjected to a sequence analysis. The most predominant group, which represented about 13% of the clones of the 16S rDNA library, was affiliated with the Holophaga/Acidobacterium phylum. Significant was also the number of the proteobacterial sequences which were distributed in one predominant α-proteobacterial cluster representing 11% of the total number of clones and in two equal-sized β- and γ-proteobacterial clusters representing each 6% of the clones. Two smaller groups representing both 2% of the clones were affiliated with Nitrospira and with the novel division WS3. Three of the analysed sequences were evaluated as a novel, not yet described lineage and one as a putative chimera. (authors)

  9. 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.)

  10. Prediction of Partition Coefficients of Organic Compounds for SPME/PDMS

    Directory of Open Access Journals (Sweden)

    Liao Hsuan-Yu

    2016-01-01

    Full Text Available The partition coefficients of 51 organic compounds between SPME/PDMS and gas were compiled from the literature sources in this study. The effect of physicochemical properties and descriptors on the partitioning process of partition coefficients was explicated by the correlation analysis. The PDMS-gas partition coefficients were well correlated to the molecular weight of organic compounds (r = 0.832, p < 0.05. An empirical model, consisting of the molecular weight and the polarizability, was developed to appropriately predict the partition coefficients of organic compounds. The empirical model for estimating the PDMS-gas partition coefficient will contribute to the practical applications of the SPME technique.

  11. Uranium conversion wastes

    International Nuclear Information System (INIS)

    Vicente, R.; Dellamano, J.C.

    1989-12-01

    A set of mathematical equations was developed and used to estimate the radiological significance of each radionuclide potentially present in the uranium refining industry effluents. The equations described the evolution in time of the radionuclides activities in the uranium fuel cycle, from mining and milling, through the yellowcake, till the conversion effluents. Some radionuclides that are not usually monitored in conversion effluents (e.g. Pa-231 and Ac-227) were found to be potentially relevant from the radiological point of view in conversion facilities, and are certainly relevant in mining and milling industry, at least in a few waste streams. (author) [pt

  12. Bio-precipitation of uranium by two bacterial isolates recovered from extreme environments as estimated by potentiometric titration, TEM and X-ray absorption spectroscopic analyses.

    Science.gov (United States)

    Merroun, Mohamed L; Nedelkova, Marta; Ojeda, Jesus J; Reitz, Thomas; Fernández, Margarita López; Arias, José M; Romero-González, María; Selenska-Pobell, Sonja

    2011-12-15

    This work describes the mechanisms of uranium biomineralization at acidic conditions by Bacillus sphaericus JG-7B and Sphingomonas sp. S15-S1 both recovered from extreme environments. The U-bacterial interaction experiments were performed at low pH values (2.0-4.5) where the uranium aqueous speciation is dominated by highly mobile uranyl ions. X-ray absorption spectroscopy (XAS) showed that the cells of the studied strains precipitated uranium at pH 3.0 and 4.5 as a uranium phosphate mineral phase belonging to the meta-autunite group. Transmission electron microscopic (TEM) analyses showed strain-specific localization of the uranium precipitates. In the case of B. sphaericus JG-7B, the U(VI) precipitate was bound to the cell wall. Whereas for Sphingomonas sp. S15-S1, the U(VI) precipitates were observed both on the cell surface and intracellularly. The observed U(VI) biomineralization was associated with the activity of indigenous acid phosphatase detected at these pH values in the absence of an organic phosphate substrate. The biomineralization of uranium was not observed at pH 2.0, and U(VI) formed complexes with organophosphate ligands from the cells. This study increases the number of bacterial strains that have been demonstrated to precipitate uranium phosphates at acidic conditions via the activity of acid phosphatase. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. 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)

  14. Uranium resources, production and demand in South Africa

    International Nuclear Information System (INIS)

    Brynard, H.J.; Ainslie, L.C.

    1990-01-01

    This paper provides a review of the historical development of the South African uranium market and the current status of uranium exploration, resources and production. A prognosticated view of possible future demand for uranium in South Africa is attempted, taking cognisance of the finite nature of the country's coal resources and estimated world uranium demand. Although well endowed with uranium resources, South Africa could face a shortage of this commodity in the next century, should the predicted electricity growth materials. (author)

  15. Uranium resources, production and demand in South Africa

    Energy Technology Data Exchange (ETDEWEB)

    Brynard, H J; Ainslie, L C [Atomic Energy Corporation of South Africa Ltd., Pretoria (South Africa)

    1990-06-01

    This paper provides a review of the historical development of the South African uranium market and the current status of uranium exploration, resources and production. A prognosticated view of possible future demand for uranium in South Africa is attempted, taking cognisance of the finite nature of the country's coal resources and estimated world uranium demand. Although well endowed with uranium resources, South Africa could face a shortage of this commodity in the next century, should the predicted electricity growth materials. (author)

  16. Features of the distribution of uranium in igneous rocks - uranium deposits associated with igneous rocks

    International Nuclear Information System (INIS)

    Soerensen, H.

    1977-01-01

    The generally accepted main features of the distribution of uranium and thorium in igneous rocks are briefly reviewed. It is pointed out that uranium in most cases examined is strongly partitioned into the melt during consolidation of magmas and that uranium is concentrated in the most volatile-rich parts of magmas. The mode of emplacement and the consolidation of magmas control the retention or the expulsion of the volatile phase from consolidating magmas and also the distribution of uranium between magmas and the volatile phase. After a brief review of the types of uranium deposits associated with igneous rocks it is concluded that it is difficult to establish universally valid exploration criteria to be used in the search of these types of deposit. It is emphasized, however, that detailed petrological and geochemical studies may be useful in outlining exploration targets. (author)

  17. Estimation of the Pitzer equation parameters for aqueous complexes. A case study for uranium at 298.15 K and 1 atm

    International Nuclear Information System (INIS)

    Plyasunov, A.; Grenthe, I.; Fanghaenel, T.

    1998-01-01

    A procedure to estimate the Pitzer parameters for complexes or complex formation reactions from a small number of equilibrium constants (log K vs. I) obtained in 'constant ionic media' is discussed in some detail. It is then often impossible to determine both log K deg., the equilibrium constant at I=0, and all Pitzer parameters, hence some estimations or other simplifications are necessary. Solution coordination chemists have therefore preferred to use the less parametrized Broensted-Guggenheim-Scatchard (SIT) model. By comparison of analytical statements for the mean activity coefficients and equilibrium constants, for the SIT and Pitzer models we have shown that they are equivalent for ionic strengths less than 4 mol kg -1 , and have also established relationships between the Pitzer parameter β (1) and the charge type of the interacting ions, and between Δβ (1) for a complex formation reaction and ΔZETA 2 for the reaction, where ΔZETA 2 is the sum of the squared charges of the reactants/products with the proper stoichiometric coefficients. The first relationship is based on data in single electrolyte systems and the second on equilibrium-constant data determined in ionic media. For reactions involving species of charges one and two in 1-1 electrolyte ionic media we recommend the use of Δβ (1) /ΔZETA 2 = 0.337±0.014 kg mol -1 for the estimation of the Δβ (1) at 298.15 K and 1 atm. In this way we have used concentration equilibrium constant data to estimate log K deg. and Pitzer parameters β (0) and β (1) for more than 30 uranium complexes with other ions at 298.15 K and 1 atm. The procedure makes it possible to use the information on complex formation, acid/base and redox equilibria obtained in ionic media together with the Pitzer parameters for strong electrolytes for the modeling of complex equilibrium systems oer a broad range of ionic strength/ionic medium compositions, up to at least 4 mol kg -1 . (au)

  18. Uranium extraction from seawater

    International Nuclear Information System (INIS)

    Bals, H.G.

    1976-03-01

    After an introduction to the physics and chemistry of the sea and an estimation of the chances for the absorption of uranium from rivers, the material-sepecific characteristics of the adsorber technology are decribed in detail. Then, the methods used for gaining uranium form seawater are described with special regard to the tidal and the so-called serial (sequency) method. Whether all methods described can be realised is an economic problem since very high quantitics of water are necessary because of the low contents of uranium. A positive energy balance (gained energy/lost energy) is not definitely ensured yet for the production methods used. The development measures to be taken to obtain a positive energy balance are briefly described, and the research programme of the UEBG is mentioned. (UA) [de

  19. Uranium development in Nigeria

    International Nuclear Information System (INIS)

    Karniliyus, J.; Egieya, J.

    2014-01-01

    Nigeria uranium exploration started in 1973. Uranium was found in seven states of the country; Cross River, Adamawa, Taraba, Plateau, Bauchi, Kogi and Kano. Three government agencies were involved. At the end of the various exploration campaigns in 2001, the uranium reserve was estimated at about 200 t U. The Grade ranges from 0.63% - 0-9% at a vertical depth between 130 – 200 m. Currently, the Nigeria Atomic Energy Commission activated in 2006 is charged with the responsibility among others to prospect for and mine radioactive minerals. The main aim of this poster presentation is to review the development of uranium in Nigeria with a view to encourage local and international investors to develop and exploit these deposits. Nigeria is located on latitude 100 N and longitude 80 E surrounded in the north by Niger and Chad, in the east by Cameroun and in the west by the Benin Republic. Available data indicated the viability of mineral investment in the Nigerian uranium resources. With the current economic reforms and investment incentives in Nigeria, interested investors are highly welcome to take advantage of developing these mineral resources. (author)

  20. International uranium market

    International Nuclear Information System (INIS)

    Neff, T.L.; Jacoby, H.D.

    1980-12-01

    Discussed in this report are 1) how one might think about uranium demand, resources and supply, 2) how producers and consumers see the market and are likely to behave, including specifics about export and import commitments, and 3) how these actors are brought together in the international market. The general conclusion is that much of current anxiety about future uranium supply results primarily from a brief but difficult period in the mid- to late-1970's; and that current conditions and trends are favorable (at least to consumers) that there is now little basis for concern. Inventories contractual positions and producer commitments--when compared with realistic (or even unrealistic) demand estimates--imply a buyer's market for at least the next decade. The result will be considerable increases in market flexibility and resilience to shock, and real prices that are low relative to those of the past few years. There is a need to reconsider assumptions about desired directions of technological development, for many current programs were planned in an era of pessimism about uranium supply and process. Similar questions must be raided about nonproliferation policies that depend on some level of control of fuel supplies by the industrial nations. With a soft and more diversified uranium market, leverage that may have existed in the past is rapidly being eroded. Finally, as world prices turn soft, there may be significant problems created for U.S. uranium producers, who have relatively high costs in relation to several large-scale foreign suppliers

  1. The prediction of blood-tissue partitions, water-skin partitions and skin permeation for agrochemicals.

    Science.gov (United States)

    Abraham, Michael H; Gola, Joelle M R; Ibrahim, Adam; Acree, William E; Liu, Xiangli

    2014-07-01

    There is considerable interest in the blood-tissue distribution of agrochemicals, and a number of researchers have developed experimental methods for in vitro distribution. These methods involve the determination of saline-blood and saline-tissue partitions; not only are they indirect, but they do not yield the required in vivo distribution. The authors set out equations for gas-tissue and blood-tissue distribution, for partition from water into skin and for permeation from water through human skin. Together with Abraham descriptors for the agrochemicals, these equations can be used to predict values for all of these processes. The present predictions compare favourably with experimental in vivo blood-tissue distribution where available. The predictions require no more than simple arithmetic. The present method represents a much easier and much more economic way of estimating blood-tissue partitions than the method that uses saline-blood and saline-tissue partitions. It has the added advantages of yielding the required in vivo partitions and being easily extended to the prediction of partition of agrochemicals from water into skin and permeation from water through skin. © 2013 Society of Chemical Industry.

  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. Determination of uranium content in dental porcelains by means of the fission track method and estimation of radiation dose to oral mucosa by radioactive elements

    International Nuclear Information System (INIS)

    Sairenji, E.; Moriwaki, K.; Shimizu, M.; Noguchi, K.

    1980-01-01

    Porcelain teeth, some of which contain uranium compounds for aesthetic purpose, have been widely used in dental clinics. Hazardous effects due to uranium radiation have been suggested in recent publications. In the present study uranium concentrations were determined in four major brands of porcelain teeth marketed in Japan using the fission track method, and the absorbed doses to oral tissued were calculated. Average uranium concentrations of the brands studied were determined to be 3.6 ppm (0.33-10 ppm, Japan), 18 ppm (0.69-81 ppm, Japan), 9.4 ppm (2.5-14 ppm, Japan) and 82 ppm (11-205 ppm, U.S.), respectively. The corresponding dose equivalents at the surface of oral mucosal membrane were 2.9 rem yr -1 . 14 rem yr -1 , 7.6 rem yr -1 and 66 rem yr -1 . (author)

  5. Determination of uranium content in dental porcelains by means of the fission track method and estimation of radiation dose to oral mucosa by radioactive elements

    International Nuclear Information System (INIS)

    Sairenji, Eiko; Moriwaki, Kazunari; Shimizu, Masami; Noguchi, Kunikazu; Anzai, Ikuro.

    1979-01-01

    Porcelain teeth, some of which contained uranium compounds for aesthetic purpose, have been widely used in dental clinics. Recently, the hazardous effects by uranium radiation were suggested. In the present study, the authors carried out the determination of uranium concentrations of four major brands of porcelain teeth marketed in Japan using the fission track method, and the absorbed doses of oral tissues were calculated by the authors' introduced formula for calculation of alpha radiation. Average uranium concentrations of the brands studied were determined 3.6 ppm (0.33 - 10 ppm, Japan), 18 ppm (0.69 - 81 ppm, Japan), 9.4 ppm (2.5 - 14 ppm, Japan) and 82 ppm (11 - 205 ppm, U.S.A.), respectively. The corresponding dose equivalents at the surface of oral mucosal membrane were 2.9 rem y -1 , 14 rem y -1 , 7.6 rem y -1 and 66 rem y -1 . (author)

  6. Partitional clustering algorithms

    CERN Document Server

    2015-01-01

    This book summarizes the state-of-the-art in partitional clustering. Clustering, the unsupervised classification of patterns into groups, is one of the most important tasks in exploratory data analysis. Primary goals of clustering include gaining insight into, classifying, and compressing data. Clustering has a long and rich history that spans a variety of scientific disciplines including anthropology, biology, medicine, psychology, statistics, mathematics, engineering, and computer science. As a result, numerous clustering algorithms have been proposed since the early 1950s. Among these algorithms, partitional (nonhierarchical) ones have found many applications, especially in engineering and computer science. This book provides coverage of consensus clustering, constrained clustering, large scale and/or high dimensional clustering, cluster validity, cluster visualization, and applications of clustering. Examines clustering as it applies to large and/or high-dimensional data sets commonly encountered in reali...

  7. Why partition nuclear waste

    International Nuclear Information System (INIS)

    Cohen, J.J.

    1976-01-01

    A cursory review of literature dealing with various separatory processes involved in the handling of high-level liquid nuclear waste discloses that, for the most part, discussion centers on separation procedures and methodology for handling the resulting fractions, particularly the actinide wastes. There appears to be relatively little discussion on the incentives or motivations for performing these separations in the first place. Discussion is often limited to the assumption that we must separate out ''long-term'' from our ''short-term'' management problems. This paper deals with that assumption and devotes primary attention to the question of ''why partition waste'' rather than the question of ''how to partition waste'' or ''what to do with the segregated waste.''

  8. Criticality accident in uranium fuel processing plant. Emergency medical care and dose estimation for the severely overexposed patients

    Energy Technology Data Exchange (ETDEWEB)

    Akashi, Makoto; Ishigure, Nobuhito [National Inst. of Radiological Sciences, Chiba (Japan)

    2000-08-01

    A criticality accident occurred in JCO, a plant for nuclear fuel production in 1999 and three workers were exposed to extremely high-level radiation (neutron and {gamma}-ray). This report describes outlines of the clinical courses and the medical cares for the patients of this accident and the emergent medical system for radiation accident in Japan. One (A) of the three workers of JCO had vomiting and diarrhea within several minutes after the accident and another one (B) had also vomiting within one hour after. Based on these evidences, the exposure dose of A and B were estimated to be more than 8 and 4 GyEq, respectively. Generally, acute radiation syndrome (ARS) is assigned into three phases; prodromal phase, critical or manifestation phase and recovery phase or death. In the prodromal phase, anorexia, nausea, vomiting and diarrhea often develop, whereas the second phase is asymptotic. In the third phase, various syndromes including infection, hemorrhage, dehydration shock and neurotic syndromes are apt to occur. It is known that radiation exposure at 1 Gy or more might induce such acute radiation syndromes. Based on the clinical findings of Chernobyl accident, it has been thought that exposure at 0.5 Gy or more causes a lowering of lymphocyte level and a decrease in immunological activities within 48 hours. Lymphocyte count is available as an indicator for the evaluation of exposure dose in early phase, but not in later phase The three workers of JCO underwent chemical analysis of blood components, chromosomal analysis and analysis of blood {sup 24}Na immediately after the arrival at National Institute of Radiological Sciences via National Mito Hospital specified as the third and the second facility for the emergency medical care system in Japan, respectively. (M.N.)

  9. BKP plane partitions

    International Nuclear Information System (INIS)

    Foda, Omar; Wheeler, Michael

    2007-01-01

    Using BKP neutral fermions, we derive a product expression for the generating function of volume-weighted plane partitions that satisfy two conditions. If we call a set of adjacent equal height-h columns, h > 0, an h-path, then 1. Every h-path can assume one of two possible colours. 2. There is a unique way to move along an h-path from any column to another

  10. BKP plane partitions

    Energy Technology Data Exchange (ETDEWEB)

    Foda, Omar; Wheeler, Michael [Department of Mathematics and Statistics, University of Melbourne, Parkville, Victoria 3010 (Australia)

    2007-01-15

    Using BKP neutral fermions, we derive a product expression for the generating function of volume-weighted plane partitions that satisfy two conditions. If we call a set of adjacent equal height-h columns, h > 0, an h-path, then 1. Every h-path can assume one of two possible colours. 2. There is a unique way to move along an h-path from any column to another.

  11. Generalised twisted partition functions

    CERN Document Server

    Petkova, V B

    2001-01-01

    We consider the set of partition functions that result from the insertion of twist operators compatible with conformal invariance in a given 2D Conformal Field Theory (CFT). A consistency equation, which gives a classification of twists, is written and solved in particular cases. This generalises old results on twisted torus boundary conditions, gives a physical interpretation of Ocneanu's algebraic construction, and might offer a new route to the study of properties of CFT.

  12. Problems of natural uranium supply

    Energy Technology Data Exchange (ETDEWEB)

    Huwyler, S [Eidgenoessisches Inst. fuer Reaktorforschung, Wuerenlingen (Switzerland)

    1977-11-01

    The estimated uranium reserves in the Western World and the forecast uranium requirement in this region make the supply of nuclear power stations appear guaranteed well beyond the turn of the century. At least in the next decade it will be possible to exploit the advantageous uranium reserves in low price category, provided that prospection activities are stepped up soon and production capacities are expanded in time which are not even fully utilized today. However, difficulties could arise earlier in those countries which have no uranium reserves of their own. There is an increasing tendency among uranium producing countries to link supplies of their uranium with restrictive conditions. This makes long term contractual uranium supply guarantees a most pressing matter for those countries which have no uranium of their own. Even if the delays in the addition of new nuclear power plants are likely to improve the supply situation in the next few years, supply shortages will have to be anticipated at least from the nineties onward, unless exploitation and dressing activities are expanded considerably and also low grade ores are included in the production. At the same time it appears that the use of plutonium fueled fast breeder reactors will be unavoidable in the nineties.

  13. 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

  14. 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

  15. The measurement test of uranium in a uranium-contaminated waste by passive gamma-rays measurement method

    CERN Document Server

    Sukegawa, Y; Ohki, K; Suzuki, S; Yoshida, M

    2002-01-01

    This report is completed about the measurement test and the proofreading of passive gamma - rays measurement method for Non - destructive assay of uranium in a uranium-contaminated waste. The following are the results of the test. 1) The estimation of the amount of uranium by ionization survey meter is difficult for low intensity of gamma-rays emitted from uranium under about 50g. 2) The estimation of the amount of uranium in the waste by NaI detector is possible in case of only uranium, but the estimation from mixed spectrums with transmission source (60-cobalt) is difficult to confirm target peaks. 3) If daughter nuclides of uranium and thorium chain of uranium ore exist, measurement by NaI detector is affected by gamma-rays from the daughter nuclides seriously-As a result, the estimation of the amount of uranium is difficult. 4) The measurement of uranium in a uranium-contaminated waste by germanium detector is possible to estimate of uranium and other nuclides. 5) As to estimation of the amount of uranium...

  16. 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)

  17. Establishment of THERPRO Database and Estimation of the Effect of Fuel Burn-up on the Thermal Conductivity of Uranium Dioxide

    International Nuclear Information System (INIS)

    Lee, Hyun Seon

    2005-02-01

    Materials property data are an essential part of major disciplines in many engineering fields. To nuclear engineering, fundamental understanding of thermo-physical chemical mechanical properties of nuclear materials is very important. THERPRO data base that is re-designed and re-constructed through this study is a web-based on-line nuclear materials properties data base. For the future upgrade of the data base contemporary information technologies have been incorporated during the construction. Basically THERPRO data base has a hierarchical structure consisting of several levels: home page, element, compound, property, author, report, and bibliography level. All of data sets in each level are interconnected using network structure and thus every data can be easily retrieved including the bibliographical information by an appropriate query action. As a part of THERPRO DB utilization, the effect of fuel burn-up on the thermal conductivity of irradiated uranium dioxide is analyzed with the data contained in the data base as well as recent data published in the relevant journals. Their data are comparatively studied and the effect is estimated using FRAPCON-3 code with two in-pile data sets, BR-3 111i5 and Oconee rod 15309. The results show that the fuel center line temperature can differ 200 .deg. C∼400 .deg. C from thermal conductivity models depending on burn-up, which can significantly influence high burn-up fuel performance. In conclusion, it is demonstrated through this study that THERPRO data base can be a great utility for nuclear engineers and researchers, if appropriately utilized

  18. 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

  19. Partitioning of organochlorine pesticides from water to polyethylene passive samplers

    International Nuclear Information System (INIS)

    Hale, Sarah E.; Martin, Timothy J.; Goss, Kai-Uwe; Arp, Hans Peter H.; Werner, David

    2010-01-01

    The mass transfer rates and equilibrium partitioning behaviour of 14 diverse organochlorine pesticides (OCP) between water and polyethylene (PE) passive samplers, cut from custom made PE sheets and commercial polyethylene plastic bags, were quantified. Overall mass transfer coefficients, k O , estimated PE membrane diffusion coefficients, D PE , and PE-water partitioning coefficients, K PE-water, are reported. In addition, the partitioning of three polycyclic aromatic hydrocarbons (PAHs) from water to PE is quantified and compared with literature values. K PE-water values agreed mostly within a factor of two for both passive samplers and also with literature values for the reference PAHs. As PE is expected to exhibit similar sorption behaviour to long-chain alkanes, PE-water partitioning coefficients were compared to hexadecane-water partitioning coefficients estimated with the SPARC online calculator, COSMOtherm and a polyparameter linear free energy relationship based on the Abraham approach. The best correlation for all compounds tested was with COSMOtherm estimated hexadecane-water partitioning coefficients. - The partitioning of organochlorine pesticides between single phase polyethylene passive samplers and water is quantified.

  20. Kvanefjeld uranium project

    International Nuclear Information System (INIS)

    Erlendsson, G.; Jensen, J.; Kofoed, S.; Paulsen, J.L.

    1983-11-01

    The draft uranium project ''Kvanefjeld'' describes the establishment and operation of an industrial plant for exploiting the uranium deposit at Kvanefjeld. The draft project is part of the overall pre-feasibility project and is based on its results. The draft project includes two alternative locations for the processing plant and the tailings deposit plant. The ore reserve is estimated at 56 million tons with an average content of 365 PPM. The mine will be established as an open pit, with a slope angle of 55deg. Conventional techniques are used in drilling, blasting and handling the ore. Waste rock with no uranium content will be disposed of in two ponds near the mine. The waste rock volume is estimated at 80 million tons. A processing plant for extracting uranium from the ore will be established. The technical layout of the plant is based on the extraction experiments performed at Risoe from 1981-83. Yearly capacity is 4.2 million tons of ore. Electrical energy will be supplied from a hydroelectric station to be built at Johan Dahl Land. Thermal energy (steam/heat) will be supplied from a coal-fired district heating plant to be built in connection with the processing plant. Expected power consumption is estimated at 225 GWh/year. Heat consumption is of the same order. In the third year the plant is expected to operate at full capacity. Operating costs will be Dkr. 121/ton of ore from years 1 through 7. Consumption of chemicals will be reduced from the 7th year, and operating costs will consequently drop to Dkr. 115/ton of ore. Calculations show that industrial extraction of the uranium deposit in Kvanefjeld is economically advantageous. In addition, the economy of the project is expected to improve by extracting byproducts from the ore. (EG)

  1. Uranium resources: the Canadian status

    International Nuclear Information System (INIS)

    Runnalls, O.J.C.

    1976-01-01

    The history of the uranium industry in Canada is reviewed beginning with the first discoveries and progressing through the booming years of the 1950's, the doldrums of the 1960's, to the present bouyant seller's market and the promising prospects for new discoveries. The upsurge in demand has led to the establishment of a uranium export policy which is described in detail. Recent estimates of resources, production capacity, and domestic demand are also outlined. Finally, a brief description of the utilization of natural uranium in CANDU power reactors is presented

  2. Uranium 2005 Resources, Production and Demand

    CERN Document Server

    Organisation for Economic Cooperation and Development. Paris. Nuclear Energy Agency

    2006-01-01

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

  3. Uranium 2014 resources, production and demand

    CERN Document Server

    Organisation for Economic Cooperation and Development. Paris

    2014-01-01

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

  4. Uranium ore mining in the future

    International Nuclear Information System (INIS)

    Ertle, H.J.; Schmid, K.

    1979-01-01

    Since energy supply has to be secured in the long term (hardly without a uranium contribution), the disparate laws governing the uranium market need a closer lock, taking into account the economic advantages or uranium as compared with other energies, the strategic importance, market fluctuations and price formation. Regarding costs, the paper highlights the imbalance between the modest increase in uranium reserves and the steadily growing production costs over the last four years. In this context, the pattern of exploration outlays of a number of countries active in the uranium field since 1972 and the size of the main uranium reserves of the Western World are relevant. Lastly, an attempt is made to estimate uranium availability, production and demand for the period 1985 to 1990 on the basis of two scenarios, one based on a moderate rate of nuclear power development and one on an accelerated rate. (orig./HS) [de

  5. 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.

  6. 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.'

  7. Space-partition method for the variance-based sensitivity analysis: Optimal partition scheme and comparative study

    International Nuclear Information System (INIS)

    Zhai, Qingqing; Yang, Jun; Zhao, Yu

    2014-01-01

    Variance-based sensitivity analysis has been widely studied and asserted itself among practitioners. Monte Carlo simulation methods are well developed in the calculation of variance-based sensitivity indices but they do not make full use of each model run. Recently, several works mentioned a scatter-plot partitioning method to estimate the variance-based sensitivity indices from given data, where a single bunch of samples is sufficient to estimate all the sensitivity indices. This paper focuses on the space-partition method in the estimation of variance-based sensitivity indices, and its convergence and other performances are investigated. Since the method heavily depends on the partition scheme, the influence of the partition scheme is discussed and the optimal partition scheme is proposed based on the minimized estimator's variance. A decomposition and integration procedure is proposed to improve the estimation quality for higher order sensitivity indices. The proposed space-partition method is compared with the more traditional method and test cases show that it outperforms the traditional one

  8. Hanford soil partitioning and vapor extraction study

    International Nuclear Information System (INIS)

    Yonge, D.; Hossain, A.; Cameron, R.; Ford, H.; Storey, C.

    1996-07-01

    This report describes the testing and results of laboratory experiments conducted to assist the carbon tetrachloride soil vapor extraction project operating in the 200 West Area of the Hanford Site in Richland, Washington. Vapor-phase adsorption and desorption testing was performed using carbon tetrachloride and Hanford Site soils to estimate vapor-soil partitioning and reasonably achievable carbon tetrachloride soil concentrations during active vapor extractions efforts at the 200 West Area. (CCl 4 is used in Pu recovery from aqueous streams.)

  9. Estimated population near uranium tailings

    International Nuclear Information System (INIS)

    Bloomster, C.H.; Brown, D.R.; Bruno, G.A.; Craig, S.N.; Dirks, J.A.; Griffin, E.A.; Reis, J.W.; Young, J.K.

    1984-01-01

    Population studies, which took place during the months of April, May, and June 1983, were performed for 27 active and 25 inactive mill sites. For each mill site, a table showing population by radius (1/2, 1, 2, 3, 4, and 5 km) in 16 compass directions was generated. 22 references, 6 tables

  10. 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

  11. Comparative study of Uranium estimation in drinking water samples of seismically active regions of NW-Himalayas, Himachal Pradesh and SW-Punjab, India using Laser Fluorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Bajwa, B.; Arora, V.; Saini, K. [Guru Nanak Dev University, Amritsar (India)

    2014-07-01

    The Laser Fluorimetry Technique has been used for the microanalysis of uranium content in drinking water samples collected from different sources like the hand pumps and natural springs of seismically active regions of Chamba and Dharamshala, Himachal Pradesh, NW-Himalayas and Bathinda and Mansa districts of SW-Punjab, state, India. The purpose of this study was to investigate the uranium concentration levels of ground water being used for drinking purposes and to determine its health effects, if any, to the local population of these regions. In the present study 47 samples of drinking water collected from different villages of the seismic active belt of Chamba and Dharamshala region of Himachal Pradesh, India have been analyzed for chemical and radiological toxicity. Uranium concentration in drinking water sample of study region ranged between 2.7 μgL{sup -1} - 53.9 μgL{sup -1} with an average value of 20.1 μgL{sup -1}. In SW-Punjab, Uranium concentration in 76 drinking water samples has been found to vary between 0.13 μgL{sup -1} and 676 μgL{sup -1} with an average of 90.2 μgL{sup -1}. Data analysis reveals that, 19% samples of NW-Himalayas water have uranium concentration higher than recommended limit of 30 μgL{sup -1} (WHO, 2011) while none of the samples exceeds the threshold of 60 μgL{sup -1} recommended by AERB, DAE, India, 2004. On the other hand, 64% water samples of SW-Punjab have uranium concentration higher than recommended limit of 30 μgL{sup -1} (WHO, 2011) while 39% water samples exceeds the threshold of 60 μgL{sup -1} recommended by AERB, DAE, India, 2004. Document available in abstract form only. (authors)

  12. 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.)

  13. New Linear Partitioning Models Based on Experimental Water: Supercritical CO2 Partitioning Data of Selected Organic Compounds.

    Science.gov (United States)

    Burant, Aniela; Thompson, Christopher; Lowry, Gregory V; Karamalidis, Athanasios K

    2016-05-17

    Partitioning coefficients of organic compounds between water and supercritical CO2 (sc-CO2) are necessary to assess the risk of migration of these chemicals from subsurface CO2 storage sites. Despite the large number of potential organic contaminants, the current data set of published water-sc-CO2 partitioning coefficients is very limited. Here, the partitioning coefficients of thiophene, pyrrole, and anisole were measured in situ over a range of temperatures and pressures using a novel pressurized batch-reactor system with dual spectroscopic detectors: a near-infrared spectrometer for measuring the organic analyte in the CO2 phase and a UV detector for quantifying the analyte in the aqueous phase. Our measured partitioning coefficients followed expected trends based on volatility and aqueous solubility. The partitioning coefficients and literature data were then used to update a published poly parameter linear free-energy relationship and to develop five new linear free-energy relationships for predicting water-sc-CO2 partitioning coefficients. A total of four of the models targeted a single class of organic compounds. Unlike models that utilize Abraham solvation parameters, the new relationships use vapor pressure and aqueous solubility of the organic compound at 25 °C and CO2 density to predict partitioning coefficients over a range of temperature and pressure conditions. The compound class models provide better estimates of partitioning behavior for compounds in that class than does the model built for the entire data set.

  14. Status of uranium in Brazil

    International Nuclear Information System (INIS)

    Majdalani, S.A.; Tavares, A.M.

    2001-01-01

    Uranium exploration in Brazil was started in 1952 by the Brazilian National Research Council. This led to the discovery of the first uranium deposits in Pocos de Caldas and Jacobina. These activities was later continued by the National Energy Commission/Comissao Nacional de Energia Nuclear (CNEN), formed in 1962. The founding of NUCLEBRAS at the end of 1974 marked the increasing effort of the country's uranium exploration programme. At this time only the Pocos de Caldas deposit was known with measurable resources. Due to the reorganization of the Brazilian nuclear programme in 1988, all uranium exploration in the country was stopped. By then, eight areas with uranium reserves has been identified. Brazil uranium resources in the RAR category at ≤ $80/kg U cost range are estimated to be 162,000 tonnes U, out of which 56,100 tonnes are in the ≤ $40/kg U cost range. Additional resources in the EAR-I category and the cost range ≤ 80/kg U are in the order of 100,200 tonnes U. The first production of uranium in Brazil, at the Osamu Utsumi mine (Pocos de Caldas deposit), started in 1982. Because of escalated costs and reduced demand, this activity was put on stand-by status between 1990 and 1992. The mine was restarted in 1993, but was stopped again in October 1995. The cumulative production of the mine to 1996 was 1241 tonnes U. The Lagoa Real deposit is currently being prepared as a new producing mine. (author)

  15. Uranium distribution and availability

    International Nuclear Information System (INIS)

    Bowie, S.H.U.

    1977-01-01

    Uranium deposits are not uniformly distributed in the earth's crust but occur in well-defined provinces, mainly in Precambrian terrain and in association with acid igneous rocks. Deposits can conveniently be classified into four main groups; uranium in sandstones; uranium in conglomerates; vein-and similar-type deposits; and other uranium deposits. Most of the presently known reserves occur in sandstones; vein-type deposits are now second in importance; conglomerates are third and other deposits, excluding shales, fourth. The shales of southern Sweden constitute a special case; although recoverable reserves are large (300 000 t U), annual production from them is not likely to exceed 1000 to 2000 t U. The estimation of reserves has been complicated by rapid price rises since 1973 and by uncertainty as to what cost or price levels should be adopted in distinguishing between reserves and resources. Also there has been a tendency for requirements to be revised downwards, and this, together with the apparent acceptance of cost levels of around $30/lb U 3 O 8 , has relieved the medium-term prospects so far as supply is concerned. In the longer term, however, there is clearly a need for increased prospecting effort on a world scale and for the introduction of new search methods, particularly those aimed at the detection of hidden orebodies. this requirement will be greatly enhanced if there is any retardation in the introduction of fast reactors. (author)

  16. First-principles estimation of electronic structure of uranium oxychalcogenides UOY, Y = S, Se, Te. Application to the INS spectra of UOS

    Energy Technology Data Exchange (ETDEWEB)

    Gajek, Z. [Instytut Niskich Temperatur i Badan Strukturalnych, Polska Akademia Nauk, Skr. Poczt. 1410, 50-950 Wroclaw 2 (Poland). E-mail: gajek at int.pan.wroc.pl

    2000-01-31

    A consistent description of the electronic structure of the U{sup 4+} (5f{sup 2}) ion in the UOY (Y = S, Se, Te) compounds derived on the basis of a model first-principles calculation is presented. The crystal field potential is discussed in detail. Special attention is paid to contributions of non-equivalent ligand groups. Their competition and variation along the series explain apparently random total values of the crystal field parameters (CFPs). Discussion of an interplay of factors dependent on the coordination geometry and so called 'intrinsic parameters' describing the separated metal-ligand (ML) linear ligators points to presumably rational ranges of actual values of CFP. Contrary to some earlier findings, the calculations evidence an approximate axial character of the crystal field potential. A dependence of the intrinsic parameters on the ML distance is examined thoroughly. The new numerical data show a dependence weaker than that reported before. At small ML distances, the intrinsic parameters behave in a manner characteristic of the metallic state. Some simplifications of the common phenomenological models suggested on the basis of the ab initio calculations open new possibilities of interpretation of complex magnetic and other properties of UOY. The obtained eigenstates of the uranium ion and simulated temperature characteristics of such quantities as the magnetic susceptibility or heat capacity may serve as good reference data. The crystal field (CF) parameters estimated from first principles have been used as starting data in the conventional phenomenological description of the recent inelastic neutron scattering (INS) data reported for UOS by Amoretti et al. In contrast to the earlier phenomenological approaches the effect of the term mixing has been taken into account. In initial steps of the fitting of the INS transition energies, a variation of the CF parameters has been restricted by using the angular overlap model. Then, the CF

  17. First-principles estimation of electronic structure of uranium oxychalcogenides UOY, Y = S, Se, Te. Application to the INS spectra of UOS

    International Nuclear Information System (INIS)

    Gajek, Z.

    2000-01-01

    A consistent description of the electronic structure of the U 4+ (5f 2 ) ion in the UOY (Y = S, Se, Te) compounds derived on the basis of a model first-principles calculation is presented. The crystal field potential is discussed in detail. Special attention is paid to contributions of non-equivalent ligand groups. Their competition and variation along the series explain apparently random total values of the crystal field parameters (CFPs). Discussion of an interplay of factors dependent on the coordination geometry and so called 'intrinsic parameters' describing the separated metal-ligand (ML) linear ligators points to presumably rational ranges of actual values of CFP. Contrary to some earlier findings, the calculations evidence an approximate axial character of the crystal field potential. A dependence of the intrinsic parameters on the ML distance is examined thoroughly. The new numerical data show a dependence weaker than that reported before. At small ML distances, the intrinsic parameters behave in a manner characteristic of the metallic state. Some simplifications of the common phenomenological models suggested on the basis of the ab initio calculations open new possibilities of interpretation of complex magnetic and other properties of UOY. The obtained eigenstates of the uranium ion and simulated temperature characteristics of such quantities as the magnetic susceptibility or heat capacity may serve as good reference data. The crystal field (CF) parameters estimated from first principles have been used as starting data in the conventional phenomenological description of the recent inelastic neutron scattering (INS) data reported for UOS by Amoretti et al. In contrast to the earlier phenomenological approaches the effect of the term mixing has been taken into account. In initial steps of the fitting of the INS transition energies, a variation of the CF parameters has been restricted by using the angular overlap model. Then, the CF parameters have been

  18. 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)

  19. Aqueous biphasic extraction of uranium and thorium from contaminated soils. Final report

    International Nuclear Information System (INIS)

    Chaiko, D.J.; Gartelmann, J.; Henriksen, J.L.; Krause, T.R.; Deepak; Vojta, Y.; Thuillet, E.; Mertz, C.J.

    1995-07-01

    The aqueous biphasic extraction (ABE) process for soil decontamination involves the selective partitioning of solutes and fine particulates between two immiscible aqueous phases. The biphase system is generated by the appropriate combination of a water-soluble polymer (e.g., polyethlene glycol) with an inorganic salt (e.g., sodium carbonate). Selective partitioning results in 99 to 99.5% of the soil being recovered in the cleaned-soil fraction, while only 0.5 to 1% is recovered in the contaminant concentrate. The ABE process is best suited to the recovery of ultrafine, refractory material from the silt and clay fractions of soils. During continuous countercurrent extraction tests with soil samples from the Fernald Environmental Management Project site (Fernald, OH), particulate thorium was extracted and concentrated between 6- and 16-fold, while the uranium concentration was reduced from about 500 mg/kg to about 77 mg/kg. Carbonate leaching alone was able to reduce the uranium concentration only to 146 mg/kg. Preliminary estimates for treatment costs are approximately $160 per ton of dry soil. A detailed flowsheet of the ABE process is provided

  20. Use of tail less amphibians in system of biomonitoring for estimation of influencing of wastes of enterprises on processing of uranium ore on zoocenosis

    International Nuclear Information System (INIS)

    Misyura, A.N.; Marchenkovskaya, A.A.

    2006-01-01

    The researches of influencing of wastes of enterprises on processing of uranium ore showed that by the sole type of amphibious, dwelling in sewage of amphibians - lake frog. Individuals of senior age groups of this type of amphibians partly oneself adapted to influencing of pollutants sewage due to the change of physiology-biochemical parameters of the organs, actively participating in metabolism. (authors)

  1. 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

  2. Uranium in South Africa: 1985

    International Nuclear Information System (INIS)

    1986-03-01

    South Africa's participation in the nuclear industry was limited to the production of uranium and research, with minor commercial activities. The commissioning of the Koeberg Nuclear power station in 1984 placed South Africa firmly on the path of commercial nuclear power generation. A unique, locally developed uranium enrichment process will enable South Africa to be self-sufficient in its nuclear-fuel needs. Uranium has always been of secondary importance to gold as a target commodity in the exploration of the quartz-pebble conglomerates. In the Witwatersrand Basin it is estimated that in excess of R100 million was spent on exploration during 1985. This was spent primarily in the search for gold but as many of the gold reefs are uraniferous, new uranium resources are being discovered concurrently with those of gold. Uranium mineralization is present in rocks which encompass almost the whole of the geological history of South Africa. Significant mineralization is restricted to five fairly well-defined time periods. Each period is characterized by a distinct type or combination of types of mineralization. Resource estimates are divided into separate categories that reflect different levels of confidence in the quantities reported. The resource categories are further separated into levels of exploitability based on the estimated cost of their exploitation. A major part (87%) of South Africa's uranium resources is present as a by-product of gold in the quartz-pebble conglomerates of the Witwatersrand Basin. The uranium resources in the reasonably assured resources (RAR) and estimated additional resources - category I (EAR-I) catogories were 483 300 t U. Production during 1985 was 4880 t U. Although a production peaking at over 1200 t U/a is theoretically attainable, it is considered, from market projections, that a production ceilling of 10 000 t U/a would be more realistic

  3. Assessment of background gamma radiation levels using airborne gamma ray spectrometer data over uranium deposits, Cuddapah Basin, India - A comparative study of dose rates estimated by AGRS and PGRS.

    Science.gov (United States)

    Srinivas, D; Ramesh Babu, V; Patra, I; Tripathi, Shailesh; Ramayya, M S; Chaturvedi, A K

    2017-02-01

    The Atomic Minerals Directorate for Exploration and Research (AMD) has conducted high-resolution airborne gamma ray spectrometer (AGRS), magnetometer and time domain electromagnetic (TDEM) surveys for uranium exploration, along the northern margins of Cuddapah Basin. The survey area includes well known uranium deposits such as Lambapur-Peddagattu, Chitrial and Koppunuru. The AGRS data collected for uranium exploration is utilised for estimating the average absorbed rates in air due to radio-elemental (potassium in %, uranium and thorium in ppm) distribution over these known deposit areas. Further, portable gamma ray spectrometer (PGRS) was used to acquire data over two nearby locations one from Lambapur deposit, and the other from known anomalous zone and subsequently average gamma dose rates were estimated. Representative in-situ rock samples were also collected from these two areas and subjected to radio-elemental concentration analysis by gamma ray spectrometer (GRS) in the laboratory and then dose rates were estimated. Analyses of these three sets of results complement one another, thereby providing a comprehensive picture of the radiation environment over these deposits. The average absorbed area wise dose rate level is estimated to be 130 ± 47 nGy h -1 in Lambapur-Peddagattu, 186 ± 77 nGy h -1 in Chitrial and 63 ± 22 nGy h -1 in Koppunuru. The obtained average dose levels are found to be higher than the world average value of 54 nGy h -1 . The gamma absorbed dose rates in nGy h -1 were converted to annual effective dose rates in mSv y -1 as proposed by the United Nations Scientific Committee on the Effect of Atomic Radiation (UNSCEAR). The annual average effective dose rates for the entire surveyed area is 0.12 mSv y -1 , which is much lower than the recommended limit of 1 mSv y -1 by International Commission on Radiation protection (ICRP). It may be ascertained here that the present study establishes a reference data set (baseline) in these areas

  4. Gentile statistics and restricted partitions

    Indian Academy of Sciences (India)

    The partition function of Gentile statistics also has the property that it nicely interpolates between the ... We now construct the partition function for such a system which also incorporates the property of interpolation ... As in [4], we however keep s arbitrary even though for s > 2 there are no quadratic. Hamiltonian systems.

  5. Present status of uranium resource development in foreign countries, 1984

    International Nuclear Information System (INIS)

    1984-12-01

    The book of the same title as this one was published in 1983. Since then, the situation requiring the correction of the contents, such as the correction of uranium resource policy in various countries accompanying the change of uranium market condition and the change of uranium policy in Australia due to the political situation, has occurred, consequently, the revision has been made adding these new information. The confirmed resources of uranium and the resources of uranium to be added by estimation in the free world are tabulated. About each country, the organization and policy, the policy of exporting uranium and the present status of the export, the quantity of uranium resources, the production of uranium, the state of exploration and development and so on are reported. Japan has taken part in the development of uranium resources in Australia, Canada, Gabon, Zambia, Morocco, Guinea, Mali and so on. (Kako, I.)

  6. Conceptual design on uranium recovery plant from seawater

    International Nuclear Information System (INIS)

    Kato, Toshiaki; Okugawa, Katsumi; Sugihara, Yutaka; Matsumura, Tsuyoshi

    1999-01-01

    Uranium containing in seawater is extremely low concentration, which is about 3 mg (3 ppb) per 1 ton of seawater. Recently, a report on development of a more effective collector of uranium in seawater (a radiation graft polymerization product of amidoxime onto polyethylene fiber) was issued by Japan Atomic Energy Research Institute. In this paper, an outline design of a uranium recovery plant from seawater was conducted on a base of the collector. As a result of cost estimation, the collection cost of seawater uranium using this method was much higher than that of uranium mine on land and described in the Red Book for mineral uranium cost. In order to make the seawater uranium cost comparable to the on-land uranium cost, it is necessary to establish comprehensive efforts in future technical development, such as development in absorption property of uranium with the collector, resolution method using less HCl, and so forth. (G.K.)

  7. 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)

  8. 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

  9. Present status of development of uranium resources in foreign countries

    International Nuclear Information System (INIS)

    1983-10-01

    The book with the same title as this was published in 1981. Thereafter, the necessity to correct the contents arose, such as the remarkable change in uranium market condition and the change of uranium resource policy in Australia accompanying the change of regime, accordingly, the revision was carried out by adding more new information. As the main sources of the information collected in this book, 25 materials are shown. The confirmed resources of uranium in the free world as of the beginning of 1981 amounted to 2,293,000 t U, and the estimated additional resources were 2,720,000 t U. The political system and uranium policy, the present status of uranium export, the quantity of resources and the estimated amount of deposits, the uranium production and the status of uranium exploration and development of 25 foreign countries are reported. Japan has carried out uranium development activities in Australia, Canada, Niger, Gabon, Zambia and so on. (Kako, I.)

  10. Uranium - raw material reserves for coming generations

    International Nuclear Information System (INIS)

    Keutner, H.

    1981-01-01

    Large uranium occurences have been discovered in the South of Mexico. The deposits are situated in the Sierra Mixteca. Reserves of 9.400 tons had been at Mexico's disposal even before these new discoveries. The quantitiy discovered recentyl amounts to 20.000 tons. The uranium reserves available apart from those in centrally controlled economic systems are presently estimated at five million tons. Meanwhile American scientists have found out that all the rivers of the world transport about 16.000 tons of uranium from the continents into the oceans per annum. The energy value of this washed out amount of uranium corresponds to the 25-fold world power demand of today. US scientists have discovered that the oceans can provide uranium for about seven million years of the present world energy demand. While the petroleum reserves decrease worldwide it seems that the exploration of uranium has just been started. (orig.) [de

  11. Uranium 2003: resources, production and demand

    International Nuclear Information System (INIS)

    2004-01-01

    The 'Red Book', jointly prepared by the OECD Nuclear Energy Agency and the International Atomic Energy Agency, is a recognised world reference on uranium. This edition, the 20., presents the results of a thorough review of world uranium supplies and demand as of 1 January 2003 based on official information received from 43 countries. Uranium 2003: Resources, Production and Demand paints a statistical profile of the world uranium industry in the areas of exploration, resource estimates, production and reactor related requirements. It provides substantial new information from all major uranium production centres in Africa, Australia, Eastern Europe and North America and for the first time, a report for Turkmenistan. Also included are international expert analyses and projections of nuclear generating capacity and reactor-related uranium requirements through 2020. The long lead times required to bring resources into production underscore the importance of making timely decisions to pursue production capability well in advance of any supply shortfall. (author)

  12. National uranium resource evaluation, preliminary report

    International Nuclear Information System (INIS)

    1976-06-01

    The results of the initial phase of the National Uranium Resource Evaluation (NURE) are reported. NURE is a comprehensive nationwide program to evaluate uranium resources and to identify areas favorable for uranium exploration. Part I presents estimates of uranium ore reserves and potential resources available at costs (not prices) of $10, $15, and $30 per pound U 3 O 8 (uranium oxide). These estimates comprise the national uranium resource position. They are, however, preliminary because limitations of time and available geologic data prevented adequate assessment of some areas that may be favorable for potential resources. Part II presents the potential uranium resources for each of 13 regions, whose boundaries have been drawn chiefly on geologic considerations. The general geology is summarized, and the types of uranium deposits are described. Although limited geologic reconnaissance was done in various parts of the country, the report is based primarily on the compilation and evaluation of data in ERDA files. Mining companies furnished a substantial amount of information on exploration results, development, production, and future plans. Published, manuscript, and open-file reports by government agencies, universities, and research organizations were reviewed. In addition, many individuals affiliated with universities and with state and federal agencies provided supplemental geologic information. This was particularly helpful in the eastern and central states and in Alaska, where information on uranium occurrences is limited

  13. Simulation and control synthesis for a pulse column separation system for plutonium--uranium recovery

    International Nuclear Information System (INIS)

    McCutcheon, E.B.

    1975-05-01

    Control of a plutonium-uranium partitioning column was studied using a mathematical model developed to simulate the dynamic response and to test postulated separation mechanisms. The column is part of a plutonium recycle flowsheet developed for the recovery of plutonium and uranium from metallurgical scrap. In the first step of the process, decontamination from impurities is achieved by coextracting plutonium and uranium in their higher oxidation states. In the second step, reduction of the plutonium to a lower oxidation state allows partitioning of the plutonium and uranium. The use of hydroxylamine for the plutonium reduction in this partitioning column is a unique feature of the process. The extraction operations are carried out in pulse columns. (U.S.)

  14. Uranium in South Africa: 1987

    International Nuclear Information System (INIS)

    1988-06-01

    South Africa's participation in the nuclear industry was limited to the production of uranium and research, with minor commercial activities. The commissioning of the Koeberg Nuclear power station in 1984 placed South Africa firmly on the path of commercial nuclear power generation. A unique locally developed uranium enrichment process wil enable South Africa to be self-sufficient in its nuclear-fuel needs. Uranium has always been of secondary importance to gold as a target commodity in the exploration of the quartz-pebble conglomerates. In the Witwatersrand Basin it is estimated that in excess of R300 million was spend on exploration during 1987. This was spend primarily in the search for gold but as many of the gold reefs are uraniferous, new uranium resources are being discovered concurrently with those of gold. Uranium mineralization is present in rocks which encompass almost the whole of the geological history of South Africa. Significant mineralization is restricted to five fairly well-defined time periods. Each period is characterized by a distinct type or combination of types of mineralization. Resource estimates are divided into separate categories that reflect different levels of confidence in the quantities reported. The resource categories are further separated into levels of exploitability based on the estimated cost of their exploitation. A major part (87%) of South Africa's uranium resources is present as a by-product of gold in the quartz-pebble conglomerates of the Witwatersrand Basin. The uranium resources in the RAR and EAR-I categories were 536 500 t u. Production during 1987 was 3963 t u. Although a production peaking at over 1100 t U/a is theoretically attainable, it is considered, from market projections, that a production ceiling of 10 000 t U/a would be more realistic

  15. Uranium resources and requirements

    International Nuclear Information System (INIS)

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

    1975-08-01

    Australia has about 19% of the reasonably assured resources of uranium in the Western World recoverable at costs of less than $A20 per kilogram, or about 9% of the resources (reasonably assured and estimated additional) recoverable at costs of less than $A30 per kilogram. Australia's potential for further discoveries of uranium is good. Nevertheless, if Australia did not export any of these resources it would probably have only a marginal effect on the development of nuclear power; other resources would be exploited earlier and prices would rise, but not sufficiently to make the costs of nuclear power unattractive. On the other hand, this policy could deny to Australia real benefits in foreign currency earnings, employment and national development. (author)

  16. 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

  17. The uranium resources and production of Namibia

    International Nuclear Information System (INIS)

    Palfi, A.G.

    1997-01-01

    The promulgation of the Minerals (Prospecting and Mining) Act, 1992, on 1 April 1994 and the simultaneous repeal of restrictive South African legislation on reporting uranium exploration and production results, allowed the Namibian Government for the first time to present information for publication of the report ''Uranium 1995 - Resource, Production and Demand'', by the OECD Nuclear Energy Agency and the IAEA. Namibia, one of the youngest independent nations in Africa, has a large number of uranium occurrences and deposits in several geological environments. The total estimated uranium resource amounts to about 299 thousand tonnes recoverable uranium at a cost of less than US$ 130/kg U, within the known conventional resources category. The most prominent geological type of these is the unique, granite-related uranium occurrences located in the central part of the Namib Desert. Permo-Triassic age Karoo sandstone-hosted uranium deposits were subject to only limited exploration due to the down-turn of uranium prices in the latter part of 1980s, despite they very encouraging exploration results. As only limited Karoo sandstone-covered areas were tested there is still great potential for further discoveries. The planned output of Roessing Uranium Mine at 40,000 tonnes of ore per day which results in an annual production of 4536 tonnes of uranium oxide, was achieved in 1979. In case of improved uranium market conditions, Namibia is in a strong position to increase uranium production and open up new production centres to strengthen the country's position as an important uranium producer in the world. 6 figs, 2 tabs

  18. Vertical partitioning of relational OLTP databases using integer programming

    DEFF Research Database (Denmark)

    Amossen, Rasmus Resen

    2010-01-01

    A way to optimize performance of relational row store databases is to reduce the row widths by vertically partition- ing tables into table fractions in order to minimize the number of irrelevant columns/attributes read by each transaction. This pa- per considers vertical partitioning algorithms...... for relational row- store OLTP databases with an H-store-like architecture, meaning that we would like to maximize the number of single-sited transactions. We present a model for the vertical partitioning problem that, given a schema together with a vertical partitioning and a workload, estimates the costs...... applied to the TPC-C benchmark and the heuristic is shown to obtain solutions with costs close to the ones found using the quadratic program....

  19. 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

  20. 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

  1. 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

  2. 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.)

  3. Uranium availability for power generation

    International Nuclear Information System (INIS)

    Stoller, S.M.; Hogerton, J.F.

    1977-01-01

    Utilities are encouraged to participate in the effort to explore and develop adequate supplies of uranium in order to assure a high level of effort and have some control over production rates. Regulatory commissions are likewise encouraged to be receptive to utility initiatives by granting assurances of favorable rate treatment to cover investments. Confusion arises over the difference between forward coverage based on proven reserves of commercial-grade uranium and long-range availability based on potential resources. Cancellations and delays in the licensing of nuclear power plants have made it difficult for uranium suppliers to proceed with confidence. Drilling difficulties and the short productive life of most uranium mines will probably keep proven reserve levels lower than long-term plant requirements. Several approaches are outlined for developing uranium reserve estimates. ERDA projections are based on ''favorable ground'' areas where uranium deposits are most probable. It is assumed that, where a market exists, minerals will be extracted and traditional procurement methods will evolve. Since utilities are the only industry committed to a viable fuel cycle, they are justified in joining in the search for supplies

  4. Partitioning ecosystems for sustainability.

    Science.gov (United States)

    Murray, Martyn G

    2016-03-01

    Decline in the abundance of renewable natural resources (RNRs) coupled with increasing demands of an expanding human population will greatly intensify competition for Earth's natural resources during this century, yet curiously, analytical approaches to the management of productive ecosystems (ecological theory of wildlife harvesting, tragedy of the commons, green economics, and bioeconomics) give only peripheral attention to the driving influence of competition on resource exploitation. Here, I apply resource competition theory (RCT) to the exploitation of RNRs and derive four general policies in support of their sustainable and equitable use: (1) regulate resource extraction technology to avoid damage to the resource base; (2) increase efficiency of resource use and reduce waste at every step in the resource supply chain and distribution network; (3) partition ecosystems with the harvesting niche as the basic organizing principle for sustainable management of natural resources by multiple users; and (4) increase negative feedback between consumer and resource to bring about long-term sustainable use. A simple policy framework demonstrates how RCT integrates with other elements of sustainability science to better manage productive ecosystems. Several problem areas of RNR management are discussed in the light of RCT, including tragedy of the commons, overharvesting, resource collapse, bycatch, single species quotas, and simplification of ecosystems.

  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. Present status of partitioning developments

    International Nuclear Information System (INIS)

    Nakamura, Haruto; Kubota, Masumitsu; Tachimori, Shoichi

    1978-09-01

    Evolution and development of the concept of partitioning of high-level liquid wastes (HLLW) in nuclear fuel reprocessing are reviewed historically from the early phase of separating useful radioisotopes from HLLW to the recent phase of eliminating hazardous nuclides such as transuranium elements for safe waste disposal. Since the criteria in determining the nuclides for elimination and the respective decontamination factors are important in the strategy of partitioning, current views on the criteria are summarized. As elimination of the transuranium is most significant in the partitioning, various methods available of separating them from fission products are evaluated. (auth.)

  7. 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

  8. 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

  9. Applied internal dosimetry staff exposed to Uranium

    International Nuclear Information System (INIS)

    Trotta, Marisa V.; Arguelles, Maria G.

    2009-01-01

    Dosimetric calculations are performed in order to estimate the quantity of a radionuclide that is incorporated by a worker. Urine determinations of activity and mass of uranium are made in the laboratory of Personal and Area Dosimetry. The paper presents reference values concerning the activity excreted in urine due to the incorporation of uranium compounds. The compounds analyzed are natural uranium and uranium enriched to 20 %, both soluble and insoluble. According to the limits allowed for the incorporation of uranium compounds of Type F and M, we verify that the times of monitoring and the detection limits of the equipment used to determine the activity are appropriate. On the other hand, the S-type compounds determination in urine is useful in cases of accidental incorporations (above the ALI) as a first and quick estimate; MDA (0.017 Bq / L) does not allow detection in routine monitoring; measurement in lungs, and faeces should be included. (author)

  10. 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

  11. 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

  12. Choosing the best partition of the output from a large-scale simulation

    Energy Technology Data Exchange (ETDEWEB)

    Challacombe, Chelsea Jordan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Casleton, Emily Michele [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-09-26

    Data partitioning becomes necessary when a large-scale simulation produces more data than can be feasibly stored. The goal is to partition the data, typically so that every element belongs to one and only one partition, and store summary information about the partition, either a representative value plus an estimate of the error or a distribution. Once the partitions are determined and the summary information stored, the raw data is discarded. This process can be performed in-situ; meaning while the simulation is running. When creating the partitions there are many decisions that researchers must make. For instance, how to determine once an adequate number of partitions have been created, how are the partitions created with respect to dividing the data, or how many variables should be considered simultaneously. In addition, decisions must be made for how to summarize the information within each partition. Because of the combinatorial number of possible ways to partition and summarize the data, a method of comparing the different possibilities will help guide researchers into choosing a good partitioning and summarization scheme for their application.

  13. 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)

  14. 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

  15. 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.

  16. Department of Energy depleted uranium recycle

    International Nuclear Information System (INIS)

    Kosinski, F.E.; Butturini, W.G.; Kurtz, J.J.

    1994-01-01

    With its strategic supply of depleted uranium, the Department of Energy is studying reuse of the material in nuclear radiation shields, military hardware, and commercial applications. the study is expected to warrant a more detailed uranium recycle plan which would include consideration of a demonstration program and a program implementation decision. Such a program, if implemented, would become the largest nuclear material recycle program in the history of the Department of Energy. The bulk of the current inventory of depleted uranium is stored in 14-ton cylinders in the form of solid uranium hexafluoride (UF 6 ). The radioactive 235 U content has been reduced to a concentration of 0.2% to 0.4%. Present estimates indicate there are about 55,000 UF 6 -filled cylinders in inventory and planned operations will provide another 2,500 cylinders of depleted uranium each year. The United States government, under the auspices of the Department of Energy, considers the depleted uranium a highly-refined strategic resource of significant value. A possible utilization of a large portion of the depleted uranium inventory is as radiation shielding for spent reactor fuels and high-level radioactive waste. To this end, the Department of Energy study to-date has included a preliminary technical review to ascertain DOE chemical forms useful for commercial products. The presentation summarized the information including preliminary cost estimates. The status of commercial uranium processing is discussed. With a shrinking market, the number of chemical conversion and fabrication plants is reduced; however, the commercial capability does exist for chemical conversion of the UF 6 to the metal form and for the fabrication of uranium radiation shields and other uranium products. Department of Energy facilities no longer possess a capability for depleted uranium chemical conversion

  17. International Uranium Resources Evaluation Project (IUREP) national favourability studies: Israel

    International Nuclear Information System (INIS)

    1977-12-01

    The geology of Israel is relatively simple. Most of the country is underlain by sedimentary rocks of Secondary and Tertiary age. As far as the IAEA is aware no systematic exploration has been done for conventional type uranium deposits. Israel has no uranium deposits, and no high or low-grade uranium ores. However, there are uranium 'sources' which are mainly phosphate rock.Proven phosphate reserves in Israel are estimated at about 220 million tons in five different locations. The average uranium concentration is between 100 and 170 ppm. This makes the uranium content in the proven phosphate reserves of Israel to be about 25,000 tons. Together with the possibility of additional discoveries and on the assumption that the economic conditions for the production of both phosphate and uranium become favourable the Speculative Potential is placed in the 10,000 to 50,000 tonnes uranium category. (author)

  18. Application of non-reductive partial partitioning in FBR fuel reprocessing: a simulation study

    International Nuclear Information System (INIS)

    Shekhar Kumar; Koganti, S.B.

    2002-06-01

    The observed performance of conventional partitioning contactor in the Purex process in the Purex process is seldom satisfactory due to over-consumption of reductant and poor U-Pu decontamination factors. Contemporary trends indicate gradually move-over to MOX fuels for FBRs. In this scenario, it is not necessary to separate uranium and plutonium completely. By controlling the acid concentration and flow rates, it is possible to selectively strip essentially all the plutonium and part of the uranium in the aqueous stream. Therefore, a mixed product enriched in plutonium is obtained which can be precipitated and denitrated. Alternatively direct denitration by microwave heating can be used. The idea is particularly attractive for the flowsheet meant for the first core of FBTR where Pu/(U+Pu) ratio of 0.7 (in the discharged fuel) is diluted by addition of uranium to 0.3. By partial partitioning in the 2B contactor, a product enriched in plutonium (Pu/(U+Pu) ratio ∼0.6) can be obtained. After a minor uranium addition, this product will be suitable for the direct fabrication of II core of FBTR where a Pu/(U+Pu) ratio of 0.55 will be required. In a similar fashion, the enriched product can be used for multiple core zones of proposed PFBR by selective additions of uranium for each zone. To explore the feasibility of such partial partitioning step, an exhaustive simulation study was made using the in-house developed computer code SIMPSEX. 1300 simulations runs were completed for different combinations of parameters and results were analyzed. In this report, the results of this study and a possible flowsheet step have been discussed. Simultaneous variation in the flow rates has been considered and safe operating limits for the partial partitioning step have been established. (author)

  19. Hawk: A Runtime System for Partitioned Objects

    NARCIS (Netherlands)

    Ben Hassen, S.; Bal, H.E.; Tanenbaum, A.S.

    1997-01-01

    Hawk is a language-independent runtime system for writing data-parallel programs using partitioned objects. A partitioned object is a multidimensional array of elements that can be partitioned and distributed by the programmer. The Hawk runtime system uses the user-defined partitioning of objects

  20. 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

  1. 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)

  2. Constitution of a group of Czech and French uranium miners in order to estimate lung cancer risk linked to low chronic exposure to radon decay products

    International Nuclear Information System (INIS)

    Tirmarche, M.; Tomasek, L.

    1996-01-01

    West Bohemian and French uranium miners are characterized by a long duration of exposure to radon and its decay products, in comparison to most of the other groups of miners, studied in the recent international joint analysis by the National Cancer Institute (NCI) in USA. This analysis has confirmed the linearly increasing risk of lung cancer by cumulative radon exposure, describing the different factors that may influence this dose-response relationship. One of the main factors presently discussed is the influence of the exposure-rate effect: in other words, has the same cumulated exposure spread over 10 years the same risk of lung cancer as if it is cumulated in 2 years? The implication of an inverse exposure-rate effect for low chronic exposures as well as some methodological approaches will be discussed and tested by using the data of the Czech and French cohorts. These two cohorts present annual exposures varying by a factor of 5 to 10, French exposure rates being close or even less than 0.1 Working Level during the last 20 years. The project is integrated in a larger European project on uranium miners, co-ordinated by IPSN. (author)

  3. 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.)

  4. Uranium evaluation and mining techniques

    International Nuclear Information System (INIS)

    1980-01-01

    Full text: Report on an IAEA/NEA/IANEC international symposium, Buenos Aires, Argentina, 1-5 October 1979. The symposium was attended by 162 participants from 35 countries and five international organizations, with 35 observers also registered. Twenty-nine papers and two informal discussions were presented in seven sessions. Planning nuclear power programmes is fraught with a very wide range of uncertainties, some of which are the uncertainties associated with rising costs and ever-lengthening lead times, the uncertainties of the rate of growth of nuclear energy, the uncertainties caused by anti-nuclear activities, and the uncertainties of uranium resources and availability of uranium supplies. Present known resources, not all of which may actually become uranium supply before the year 2025, are slightly less than 5 million tonnes uranium. Even if all these resources could be produced, production rates from them would drop seriously in the mid-1990s. It is, therefore, most important that the uncertainty of uranium resources and availability of supply be dealt with promptly. In this respect many countries of the world have begun national programmes either to determine their uranium potential, or to explore for uranium deposits. The symposium held in Buenos Aires at the invitation of the Government of Argentina sought to provide these countries with a state-of-the-art report on the various methods of uranium resource evaluation. Developments and improvements in both new and old techniques of mineral assessment proliferate. Notable among the 'newer' methods are geostatistical estimation of ore reserves, a sophisticated method which, although still under development, has gained wide recognition. In the domain of objective measurements and sample-based estimation procedures, the older classical methods also yield acceptable estimates when properly used. But uranium ore reserves are always inadequate for long-range planning, seldom exceeding a few years' demand. An

  5. 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.

  6. 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

  7. 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.

  8. 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

  9. 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

  10. 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.

  11. 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

  12. 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

  13. 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

  14. 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.

  15. 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)

  16. World uranium: resources, production and demand

    International Nuclear Information System (INIS)

    Anon.

    1978-01-01

    The OECD Nuclear Energy Agency recently announced the publication of a new edition of its report on Uranium resources, production and demand which has been published periodically since 1965, jointly with the International Atomic Energy Agency. In addition to bringing uranium resources and production estimates up-to-date, the new edition offers a more comprehensive treatment of exploration activity and uranium availability, and includes a greater number of countries within the scope of the survey. Information on uranium demand has also been revised, in the light of more recent forecasts of the growth of nuclear power. Finally, a comparison is made between uranium availability and requirements, and the implications of this comparison analysed. The main findings and conclusions of the report are summarized here. (author)

  17. The uranium market: 1986-2000

    International Nuclear Information System (INIS)

    Lewiner, C.; Walton, D.; Sinclair-Smith, D.

    1987-01-01

    This paper summarizes the main conclusions of the 1986 supply and demand report of the Uranium Institute. The probable nuclear generating capacity is estimated for 1986-2000. Previous capacity forecasts (1981-1986) are compared with actual generating capacity. When looking at demand, a distinction has to be made between what reactor operators require to fuel reactors (reactor requirements) and what they intend to purchase (uranium procurements). This distinction is defined and discussed. The interaction between supply and demand is shown and factors affecting trade (eg government policies) are discussed. 1985 was the first year when uranium production was less than reactor requirements. This shortfall will continue for a number of years with the current excess in consumer inventories supplying the difference between reactor requirements and uranium procurements. Uranium demand should exceed production by 1988 but additional capacity should be available from planned and possible restart and possible new facilities. (U.K.)

  18. Distribution of uranium supply and enrichment

    International Nuclear Information System (INIS)

    Bamford, F.W.

    1982-01-01

    Uranium supply and demand is examined from the perspective of companies in the uranium hexafluoride (UF6) conversion business whose main interest is their sources of uranium supply and UF6 destinations because of transportation costs. Because of the variations in yellowcake transport, charges for conversion, and UF6 transport costs, most converters don't have standard prices. Companies try to look ahead to determine patterns of supplies and delivery points when they analyze the market and estimate future prices. Market analyses must take into account the purchasing policies of utilities around the world. The presentation shows North America supplying about 40% of world uranium, with about 13% of the enrichment done elsewhere. It also shows North American converters getting 53% of the business, but that will require importing uranium from outside North America. 6 tables

  19. Geochemical prospecting for thorium and uranium deposits

    International Nuclear Information System (INIS)

    Boyle, R.W.

    1982-01-01

    The basic purpose of this book is to present an analysis of the various geochemical methods applicable in the search for all types of thorium and uranium deposits. The general chemistry and geochemistry of thorium and uranium are briefly described in the opening chapter, and this is followed by a chapter on the deposits of the two elements with emphasis on their indicator (pathfinder) elements and on the primary and secondary dispersion characteristics of thorium and uranium in the vicinity of their deposits. The next seven chapters form the main part of the book and describe geochemical prospecting for thorium and uranium, stressing selection of areas in which to prospect, radiometric surveys, analytical geochemical surveys based on rocks (lithochemical surveys), unconsolidated materials (pedochemical surveys), natural waters and sediments (hydrochemical surveys), biological materials (biogeochemical surveys), gases (atmochemical surveys), and miscellaneous methods. A final brief chapter reviews radiometric and analytical methods for the detection and estimation of thorium and uranium. (Auth.)

  20. Uranium 2001: resources, production and demand

    International Nuclear Information System (INIS)

    2002-01-01

    The 'Red Book', jointly prepared by the OECD Nuclear Energy Agency and the International Atomic Energy Agency, is a recognised world reference on uranium. Its contents are based on official information received from 45 countries, supplemented by unofficial information for two others. This edition, the 19., presents the results of a thorough review of world uranium supply and demand as of 1 January 2001 and provides a statistical profile of the world uranium industry in the areas of exploration, resource estimates, production and reactor-related requirements. It provides substantial new information from all major uranium production centres in Africa, Australia, Eastern Europe and North America and, for the first time, includes a report on Tajikistan. This edition also features international expert analyses and projections of nuclear generating capacity and reactor-related uranium requirements through 2020. (authors)

  1. Uranium issues and policies: an overview

    International Nuclear Information System (INIS)

    Patterson, J.A.

    1979-01-01

    US policy is to reestablish the viability of nuclear energy and to expand the useful energy derived from uranium. A comprehensive assessment of US uranium resources is a key part of this effort. This assessment should lead to resolution of issues regarding adequacy of US uranium resources and production capability to meet long-term need in an economic manner. DOE programs on ore-reserve estimation, resource appraisal (particularly NURE), and production capability analysis are responsive to these information needs, as well as concerns regarding uranium demand, market growth, uranium prices, and foreign supply and demand. The cooperation of industry, particularly in providing basic information needed for DOE studies, is a vital element of this activity

  2. 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

  3. Estimation of ionizing radiation impact on natural Vicia cracca populations inhabiting areas contaminated with uranium mill tailings and radium production wastes

    Energy Technology Data Exchange (ETDEWEB)

    Evseeva, T.; Majstrenko, T. [Institute of Biology, Komi Scientific Center, Ural Division RAS, Kommunisticheskaya 28, 167982 Syktyvkar (Russian Federation); Geras' kin, S. [Russian Institute of Agricultural Radiology and Agroecology RAAS, 249020 Obninsk, Kaluga region (Russian Federation); Brown, J.E., E-mail: Justin.brown@nrpa.no [Norwegian Radiation Protection Authority, Grini naeringspark 13, 1332 Osteras (Norway); Belykh, E. [Institute of Biology, Komi Scientific Center, Ural Division RAS, Kommunisticheskaya 28, 167982 Syktyvkar (Russian Federation)

    2009-10-01

    Industrial areas in proximity to the Vodny settlement in the Komi Republic, Russia, have been contaminated by uranium mill tailings and radium production wastes. These areas, exhibiting high activity concentrations of naturally occurring radionuclides in soils, constitute a field laboratory where the effects of combined chronic exposures to {alpha}-, {beta}- and {gamma}-emitting radionuclides on natural plant populations can be studied. The aim of the present work was to determine dose-effect relationships and the range of doses that cause biological effects in natural Vicia cracca L. populations inhabiting the study area. The studied plant species is native to the area and is found ubiquitously. Soil and vegetation samples were taken at a reference location and six contaminated sites characterized by distinct floodplain depositional units with different enhanced levels of naturally occurring radionuclides. A large fraction of the dose at the study sites (including the reference location) was attributable to internal irradiation and {sup 226}Ra was found to be an important contributor to this component of dose. The relationship between the frequency of chromosome aberrations in seedlings' root tip cells and the absorbed dose was found to be quadratic. An exponential model provided the best result in describing the empirical dependence between the absorbed dose and both the germination capacity of seeds and the survival rate of sprouts of V. cracca. For V. cracca plants inhabiting areas contaminated with uranium mill tailings and radium production wastes, a weighted absorbed dose of 0.2 Gy (weighting factor for alpha particles = 5) during the vegetation period could be considered to be a level below which no increase in genetic variability and decrease in reproductive capacity might be observed above background.

  4. Analysis of uranium intake, risk assessments uranium content in blood and urine

    International Nuclear Information System (INIS)

    Mukesh Kumar; Prasher, Sangeeta; Singh, Surinder

    2015-01-01

    Bathinda district of Punjab is in light since the last few years because of the high mortality rate due to cancer. In order to explore the possibility of uranium as one of the causes for cancer an attempt has been made to estimate the level of uranium in the environmental samples viz. soil, water, food items and to correlate it with that in the blood and urine of the cancer patients and the normal persons of the area. The fission track technique has been employed for such studies. Though the uranium content in soil is normal and close to the world average, the uranium values in most of the water samples exceed the recommended safe limits. The cancer risk estimate from drinking of uranium contaminated water during the life time of sixty year is very high. The daily intake of Uranium for the population of these villages including the drinking water has also been estimated using the daily intake of these foodstuffs recommended by WHO and is found to exceed the typical world wide dietary intake of 0.9-4.5 μg/day. The concentration of uranium in urine and blood is found higher in cancer patients, whereas the urine excretion of uranium is lower in the cancer patients compared to the normal persons. (author)

  5. Assessment of Partitioning Processes for Transmutation of Actinides

    International Nuclear Information System (INIS)

    2010-04-01

    develop element-specific, highly durable, materials for solidification and final disposal of residual actinides; To develop advanced characterisation methods for measurement of actinide hold-up in plants for the purpose of fissile material tracking as needed for nuclear material safeguards and criticality control; To establish element specific partitioning criteria to achieve a radiotoxicity reduction of about a factor of 100; To define proliferation resistance attributes for the processes and products; To compare advantages and disadvantages of aqueous and pyro-partitioning processes; and To assess the benefits of partitioning processes by reducing public radiation exposure, decreasing final repository capacity, reducing necessity of uranium mining and, consequently, diminishing the impact of uranium mill tailings

  6. Waste management in future. Partitioning and transmutation (P and T)

    International Nuclear Information System (INIS)

    Calic, D.

    2005-01-01

    Current research and development (R and D) in radioactive waste management is mainly associated with the quantities and toxicity of high level waste and spent fuel. One of the solutions that already exists, but has not yet reached scientific and technological maturity, is the process of partitioning and transmutation (P and T). Partitioning is the selective separation of radiotoxic isotopes from reprocessing streams. After the successive partitioning has been done, the long-lived radionuclides are converted into shorter-lived or stable nuclides by process called transmutation. P and T can reduce the radiotoxic inventory of spent fuel by a factor of 100 to 1000 and can achieve the reduction of time needed to reach the radioactivity level of the uranium ore from 100,000 to 5000 years. To achieve this, the separation of plutonium, minor actinides and long-lived fission products has to be implemented as early as possible in the fuel cycle strategy. Currently, P and T is still at the research and development stage and it needs to be scaled up, before it can be introduced on an industrial scale, therefore the paper will present the current status of the development of P and T and plans for the future. (author)

  7. Uranium in river water

    International Nuclear Information System (INIS)

    Palmer, M.R.; Edmond, J.M.

    1993-01-01

    The concentration of dissolved uranium has been determined in over 250 river waters from the Orinoco, Amazon, and Ganges basins. Uranium concentrations are largely determined by dissolution of limestones, although weathering of black shales represents an important additional source in some basins. In shield terrains the level of dissolved U is transport limited. Data from the Amazon indicate that floodplains do not represent a significant source of U in river waters. In addition, the authors have determined dissolved U levels in forty rivers from around the world and coupled these data with previous measurements to obtain an estimate for the global flux of dissolved U to the oceans. The average concentration of U in river waters is 1.3 nmol/kg, but this value is biased by very high levels observed in the Ganges-Brahmaputra and Yellow rivers. When these river systems are excluded from the budget, the global average falls to 0.78 nmol/kg. The global riverine U flux lies in the range of 3-6 x 10 7 mol/yr. The major uncertainty that restricts the accuracy of this estimate (and that of all other dissolved riverine fluxes) is the difficulty in obtaining representative samples from rivers which show large seasonal and annual variations in runoff and dissolved load

  8. 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

  9. Study on the radiotoxicology of enriched uranium

    International Nuclear Information System (INIS)

    Zhu Shoupeng; Zheng Siying; Wang Guolin; Wang Chongdao; Cao Genfa

    1987-12-01

    A study on the retentive peculiarity of soluble enriched uranium UO 2 F 2 were observed after iv once or consecutive ip qd x 3d to Wistar male rats. The dynamic retention of radioactivity in the body showed that the enriched uranium UO 2 F 2 was chiefly localized in kidney, and then in skeleton and liver. The radioactivity of the enriched uranium UO 2 F 2 in skeleton rose steadily while the concentratoin in kidney and liver droped. When enriched uranium UO 2 F 2 was accumulated in organism, it caused chromosome aberrations on bone marrow cells. Results indicated that the chromosome aberration rates were elevated when the dose of the enriched uranium UO 2 F 2 was increased, at the same time, the cell division was depressed. Accumulation of insoluble enriched uranium U 3 O 8 in gastrointestinal tract was well described by a two exponential expression. Values of retention estimate for fast component, T 1 = 0.34 d, and for relatively long term component, T 2 = 4.05 d. The deposition of UO 2 F 2 in the intact skin was only 0.16 to 0.18% of the total contaminated UO 2 F 2 . Penetration of the enriched uranium UO 2 F 2 was dominantly increased in abraded skin. This value is about 25 to 32 times as compaired with that in intact skin. Retention of the enriched uranium UO 2 F 2 through abraded skins was dominantly localized in kidney and skeleton

  10. Analysis of load balance in hybrid partitioning | Talib | Botswana ...

    African Journals Online (AJOL)

    In information retrieval systems, there are three types of index partitioning schemes - term partitioning, document partitioning, and hybrid partitioning. The hybrid-partitioning scheme combines both term and document partitioning schemes. Term partitioning provides high concurrency, which means that queries can be ...

  11. 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)

  12. Uptake of uranium by aquatic plants growing in fresh water ecosystem around uranium mill tailings pond at Jaduguda, India

    Energy Technology Data Exchange (ETDEWEB)

    Jha, V.N., E-mail: jhavn1971@gmail.com; Tripathi, R.M., E-mail: tripathirm@yahoo.com; Sethy, N.K., E-mail: sethybarc@rediffmail.com; Sahoo, S.K., E-mail: sksbarc@gmail.com

    2016-01-01

    Concentration of uranium was determined in aquatic plants and substrate (sediment or water) of fresh water ecosystem on and around uranium mill tailings pond at Jaduguda, India. Aquatic plant/substrate concentration ratios (CRs) of uranium were estimated for different sites on and around the uranium mill tailings disposal area. These sites include upstream and downstream side of surface water sources carrying the treated tailings effluent, a small pond inside tailings disposal area and residual water of this area. Three types of plant groups were investigated namely algae (filamentous and non-filamentous), other free floating & water submerged and sediment rooted plants. Wide variability in concentration ratio was observed for different groups of plants studied. The filamentous algae uranium concentration was significantly correlated with that of water (r = 0.86, p < 0.003). For sediment rooted plants significant correlation was found between uranium concentration in plant and the substrate (r = 0.88, p < 0.001). Both for other free floating species and sediment rooted plants, uranium concentration was significantly correlated with Mn, Fe, and Ni concentration of plants (p < 0.01). Filamentous algae, Jussiaea and Pistia owing to their high bioproductivity, biomass, uranium accumulation and concentration ratio can be useful for prospecting phytoremediation of stream carrying treated or untreated uranium mill tailings effluent. - Highlights: • Uranium mill tailings pond. • Jaduguda, India. • Fresh water plants. • Uranium uptake. • Relationship of uranium with stable elements.

  13. Potentiometric determination of hexavalent uranium in uranium silicide samples

    International Nuclear Information System (INIS)

    Arlegui, Oscar

    1999-01-01

    The Chilean Nuclear Energy Commission's Department of Nuclear Materials has among its projects the production of fuels elements for nuclear reactors, and, therefore, the Chemical Analysis Laboratory must have a rapid and reliable method for uranium analysis, to control the uranium concentration during each stage of the production process. For this reason the Chilean Nuclear Energy Commission's Chemical Analysis Laboratory has validated a potentiometric method, which is a modification of the Davies and Gray method proposed by A.R. Eberle. This method uses the Potentiometric Titration Technique and is based on the direct and rapid reduction of uranium (VI) to Uranium (IV), in a concentrated phosphoric acid medium, with excess iron (II) used as a reducing agent. In this medium the excess iron (II) selectively oxidizes to iron (III) with nitric acid, using molybdenum (IV) as a catalyzer, the nitrous acid that is produced is eliminated by adding amidosulfuric acid. The solution is diluted with 1M sulfuric acid and the uranium (IV) obtained is titrated potentiometrically with potassium dichromate in the presence of vanadilic sulfate to obtain a better defined final titration point. The samples were softened with hydrochloric acid and nitric acid and later 50 ml were estimated in a 20% sulfuric acid medium. The analytical method was validated by comparing it with Certified Reference Material (C.R.M.) from the New Brunswick Laboratory (NBL), Metallic Uranium, CRM 112-A. The F Test and the T Test show that the value calculated is less than the tabulated value so the result is traceable to the reference material. The quantification limit, sensitivity, precision and accuracy were quantified for the method

  14. Uranium and the War: The effects of depleted uranium weapons in Iraq

    International Nuclear Information System (INIS)

    Jon williams

    2007-01-01

    The U.S. Army revealed in March 2003 that it dropped between 320 and 390 tons of depleted uranium during the Gulf War-the first time the material was ever used in combat-and it is estimated that more still has been dropped during the current invasion, though there have been no official counts as yet. Nuclear weapons and nuclear power plants require highly radioactive uranium, so the uranium 238 is removed from the naturally occurring uranium by a process known as enrichment. Depleted uranium is the by-product of the uranium enrichment process. Depleted uranium was a major topic of discussion during a Feb. 24 forum at Santa Cruz with speakers from the Iraq Veterans Against War (IVAW). The panel consisted of five members of the IVAW chapter in Olympia, Washington who visited Santa Cruz as part of a speaking tour of the west coast. These members of the IVAW believe that their experiences in the Gulf War were the beginnings of what will be a long-term health problem in the region. A study conducted by the Pentagon in 2002 predicted that every future battlefield will be contaminated with depleted uranium. Up-to-date health information from Iraq is difficult to come by. But a November report from Al-jazeera concluded that the cancer rate in Iraq has increased tenfold, and the number of birth defects has multiplied fivefold times since the 1991 war. The increase is believed to be caused by depleted uranium.

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

    International Nuclear Information System (INIS)

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

    1982-11-01

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

  16. Predicting radon flux from uranium mill tailings

    International Nuclear Information System (INIS)

    Freeman, H.D.; Hartley, J.N.

    1983-11-01

    Pacific Northwest Laboratory (PNL), under contract to the US Department of Energy (DOE) Uranium Mill Tailings Remedial Action Project (UMTRAP) office, is developing technology for the design of radon barriers for uranium mill tailings piles. To properly design a radon cover for a particular tailings pile, the radon flux emanating from the bare tailings must be known. The tailings characteristics required to calculate the radon flux include radium-226 content, emanating power, bulk density, and radon diffusivity. This paper presents theoretical and practical aspects of estimating the radon flux from an uranium tailings pile. Results of field measurements to verify the calculation methodology are also discussed. 24 references, 4 figures, 4 tables

  17. 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

  18. 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.

  19. 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

  20. 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

  1. 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

  2. Gentile statistics and restricted partitions

    Indian Academy of Sciences (India)

    In a recent paper (Tran et al, Ann. Phys. 311, 204 (2004)), some asymptotic number theoretical results on the partitioning of an integer were derived exploiting its connection to the quantum density of states of a many-particle system. We generalise these results to obtain an asymptotic formula for the restricted or coloured ...

  3. Monomial Crystals and Partition Crystals

    Science.gov (United States)

    Tingley, Peter

    2010-04-01

    Recently Fayers introduced a large family of combinatorial realizations of the fundamental crystal B(Λ0) for ^sln, where the vertices are indexed by certain partitions. He showed that special cases of this construction agree with the Misra-Miwa realization and with Berg's ladder crystal. Here we show that another special case is naturally isomorphic to a realization using Nakajima's monomial crystal.

  4. Hemisphere partition function and monodromy

    Energy Technology Data Exchange (ETDEWEB)

    Erkinger, David; Knapp, Johanna [Institute for Theoretical Physics, TU Wien,Wiedner Hauptstrasse 8-10, 1040 Vienna (Austria)

    2017-05-29

    We discuss D-brane monodromies from the point of view of the gauged linear sigma model. We give a prescription on how to extract monodromy matrices directly from the hemisphere partition function. We illustrate this procedure by recomputing the monodromy matrices associated to one-parameter Calabi-Yau hypersurfaces in weighted projected space.

  5. Long-term outlook for global natural uranium and uranium enrichment supply and demand situations after the impact of Fukushima Daiichi Nuclear Power Plant accident

    International Nuclear Information System (INIS)

    Matsuo, Yuhji; Murakami, Tomoko

    2012-01-01

    In this paper, the authors propose long-term projections of global nuclear power generation, uranium production, and uranium enrichment capacities by region, and estimate the trade flows of natural uranium and uranium enrichment activities in 2020 and 2035. In spite of the rapid nuclear power generation capacity growth expected especially in Asia, the natural uranium and uranium enrichment trade will not be tightened by 2020 due to the projected increase in both natural uranium production and uranium enrichment capacities, which may cause a drop in natural uranium and uranium enrichment prices. Thus, there is a great possibility that the current projects for capacity expansion will be delayed considerably. However, in the 'high-demand scenario', where nuclear expansion will be accelerated due to growing concerns about global warming and energy security issues, additional investments in uranium production and enrichment facilities will be needed by 2035. In Asia, the self-sufficiency ratio for both natural uranium supply and uranium enrichment activities will remain relatively low until 2035. However, the Herfindahl-Hirschman (HH) index of natural uranium and uranium enrichment activity trade to Asia will be lowered considerably up to 2035, indicating that nuclear capacity expansion can contribute to enhancing energy security in Asia. (author)

  6. 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)

  7. 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.

  8. SVOC partitioning between the gas phase and settled dust indoors

    Science.gov (United States)

    Weschler, Charles J.; Nazaroff, William W.

    2010-09-01

    Semivolatile organic compounds (SVOCs) are a major class of indoor pollutants. Understanding SVOC partitioning between the gas phase and settled dust is important for characterizing the fate of these species indoors and the pathways by which humans are exposed to them. Such knowledge also helps in crafting measurement programs for epidemiological studies designed to probe potential associations between exposure to these compounds and adverse health effects. In this paper, we analyze published data from nineteen studies that cumulatively report measurements of dustborne and airborne SVOCs in more than a thousand buildings, mostly residences, in seven countries. In aggregate, measured median data are reported in these studies for 66 different SVOCs whose octanol-air partition coefficients ( Koa) span more than five orders of magnitude. We use these data to test a simple equilibrium model for estimating the partitioning of an SVOC between the gas phase and settled dust indoors. The results demonstrate, in central tendency, that a compound's octanol-air partition coefficient is a strong predictor of its abundance in settled dust relative to its gas phase concentration. Using median measured results for each SVOC in each study, dustborne mass fractions predicted using Koa and gas-phase concentrations correlate reasonably well with measured dustborne mass fractions ( R2 = 0.76). Combined with theoretical understanding of SVOC partitioning kinetics, the empirical evidence also suggests that for SVOCs with high Koa values, the mass fraction in settled dust may not have sufficient time to equilibrate with the gas phase concentration.

  9. The influence of hydrogen bonding on partition coefficients

    Science.gov (United States)

    Borges, Nádia Melo; Kenny, Peter W.; Montanari, Carlos A.; Prokopczyk, Igor M.; Ribeiro, Jean F. R.; Rocha, Josmar R.; Sartori, Geraldo Rodrigues

    2017-02-01

    This Perspective explores how consideration of hydrogen bonding can be used to both predict and better understand partition coefficients. It is shown how polarity of both compounds and substructures can be estimated from measured alkane/water partition coefficients. When polarity is defined in this manner, hydrogen bond donors are typically less polar than hydrogen bond acceptors. Analysis of alkane/water partition coefficients in conjunction with molecular electrostatic potential calculations suggests that aromatic chloro substituents may be less lipophilic than is generally believed and that some of the effect of chloro-substitution stems from making the aromatic π-cloud less available to hydrogen bond donors. Relationships between polarity and calculated hydrogen bond basicity are derived for aromatic nitrogen and carbonyl oxygen. Aligned hydrogen bond acceptors appear to present special challenges for prediction of alkane/water partition coefficients and this may reflect `frustration' of solvation resulting from overlapping hydration spheres. It is also shown how calculated hydrogen bond basicity can be used to model the effect of aromatic aza-substitution on octanol/water partition coefficients.

  10. Development of partitioning method

    International Nuclear Information System (INIS)

    Kubota, Kazuo; Dojiri, Shigeru; Kubota, Masumitsu

    1988-10-01

    The literature survey was carried out on the amount of natural resources, behaviors in reprocessing process and in separation and recovery methods of the platinum group elements and technetium which are contained in spent fuel. The essential results are described below. (1) The platinum group elements, which are contained in spent fuel, are quantitatively limited, compared with total demand for them in Japan. And estimated separation and recovery cost is rather high. In spite of that, development of these techniques is considered to be very important because the supply of these elements is almost from foreign resources in Japan. (2) For recovery of these elements, studies of recovery from undisolved residue and from high level liquid waste (HLLW) also seem to be required. (3) As separation and recovery methods, following techniques are considered to be effective; lead extraction, liquid metal extraction, solvent extraction, ion-exchange, adsorption, precipitation, distillation, electrolysis or their combination. (4) But each of these methods has both advantages and disadvantages. So development of such processes largely depends on future works. (author) 94 refs

  11. EXTENSION OF FORMULAS FOR PARTITION FUNCTIONS

    African Journals Online (AJOL)

    Ladan et al.

    2Department of Mathematics, Ahmadu Bello University, Zaria. ... 2 + 1 + 1. = 1 + 1 + 1 + 1. Partition function ( ). Andrew and Erikson (2004) stated that the ..... Andrews, G.E., 1984, The Theory of Partitions, Cambridge ... Pure Appl. Math.

  12. Optimisation of parameters for co-precipitation of uranium and plutonium - results of simulation studies

    International Nuclear Information System (INIS)

    Pandey, N.K.; Velvandan, P.V.; Murugesan, S.; Ahmed, M.K.; Koganti, S.B.

    1999-01-01

    Preparation of plutonium oxide from plutonium nitrate solution generally proceeds via oxalate precipitation route. In a nuclear fuel reprocessing scheme this step succeeds the partitioning step (separation of uranium and plutonium). Results of present studies confirm that it is possible to avoid partitioning step and recover plutonium and uranium as co-precipitated product. This also helps in minimising the risk of proliferation of fissile material. In this procedure, the solubility of uranium oxalate in nitric acid is effectively used. Co-precipitation parameters are optimised with simulated solutions of uranium nitrate and thorium nitrate (in place of plutonium). On the basis of obtained results a reconversion flow-sheet is designed and reported here. (author)

  13. Uranium abundance in some sudanese phosphate ores

    International Nuclear Information System (INIS)

    Adam, A.A.; Eltayeb, M.A.H.

    2009-01-01

    This work was carried out mainly to analysis of some Sudanese phosphate ores, for their uranium abundance and total phosphorus content measured as P 2 O 5 %. For this purpose, 30 samples of two types of phosphate ore from Eastern Nuba Mountains, in Sudan namely, Kurun and Uro areas were examined. In addition, the relationship between uranium and major, and trace elements were obtained, also, the natural radioactivity of the phosphate samples was measured, in order to characterize and differentiate between the two types of phosphate ores. The uranium abundance in Uro phosphate with 20.3% P 2 O 5 is five time higher than in Kurun phosphate with 26.7% P 2 O 5 . The average of uranium content was found to be 56.6 and 310 mg/kg for Kurun and Uro phosphate ore, respectively. The main elements in Kurun and Uro phosphate ore are silicon, aluminum, and phosphorus, while the most abundant trace elements in these two ores are titanium, strontium and barium. Pearson correlation coefficient revealed that uranium in Kurun phosphate shows strong positive correlation with P 2 O 5 , and its distribution is essentially controlled by the variations of P2O5 concentration, whereas uranium in Uro phosphate shows strong positive correlation with strontium, and its distribution is controlled by the variations of Sr concentration. Uranium behaves in different ways in Kurun phosphate and in Uro phosphate. Uro phosphate shows higher concentrations of all the estimated radionuclides than Kurun phosphate. According to the obtained results, it can be concluded that Uro phosphate is consider as secondary uranium source, and is more suitable for uranium recovery, because it has high uranium abundance and low P 2 O 5 %, than Kurun phosphate. (authors) [es

  14. Colloids from the aqueous corrosion of uranium nuclear fuel

    Science.gov (United States)

    Kaminski, M. D.; Dimitrijevic, N. M.; Mertz, C. J.; Goldberg, M. M.

    2005-12-01

    Colloids may enhance the subsurface transport of radionuclides and potentially compromise the long-term safe operation of the proposed radioactive waste repository at Yucca Mountain. Little data is available on colloid formation for the many different waste forms expected to be buried in the repository. This work expands the sparse database on colloids formed during the corrosion of metallic uranium nuclear fuel. We characterized spherical UO 2 and nickel-rich montmorilonite smectite-clay colloids formed during the corrosion of uranium metal fuel under bathtub conditions at 90 °C. Iron and chromium oxides and calcium carbonate colloids were present but were a minor population. The estimated upper concentration of the UO 2 and clays was 4 × 10 11 and 7 × 10 11-3 × 10 12 particles/L, respectively. However, oxygen eventually oxidized the UO 2 colloids, forming long filaments of weeksite K 2(UO 2) 2Si 6O 15 · 4H 2O that settled from solution, reducing the UO 2 colloid population and leaving predominantly clay colloids. The smectite colloids were not affected by oxygen. Plutonium was not directly observed within the UO 2 colloids but partitioned completely to the colloid size fraction. The plutonium concentration in the colloidal fraction was slightly higher than the value used in the viability assessment model, and does not change in concentration with exposure to oxygen. This paper provides conclusive evidence for single-phase radioactive colloids composed of UO 2. However, its impact on repository safety is probably small since oxygen and silica availability will oxidize and effectively precipitate the UO 2 colloids from concentrated solutions.

  15. 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

  16. Environmental significance of copper, lead, manganese, uranium and zinc speciation in the event of contaminated waters release from the Ranger Uranium Mining Complex

    International Nuclear Information System (INIS)

    Noller, B.N.; Currey, N.A.

    1983-01-01

    The likely impact of the accidental release of tailings dam water during the dry season at the Ranger Uranium Mining Complex was examined. A speciation scheme utilising sizing by filtration and ion-exchange with Chelex 100 has given an insight into the likely partitioning of zinc, copper, lead, manganese and uranium following the addition of tailings dam water to samples from waterbodies in the vicinity of the uranium mining/milling complex. The speciation findings are discussed in terms of likely toxic effects on fish

  17. 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

  18. Uranium from seawater

    International Nuclear Information System (INIS)

    1974-12-01

    The report concerns the possibilities of extracting uranium from seawater using either 'tidal' and 'pumped' schemes. It was decided to undertake an initial exercise on the pumped scheme. It was to take into account not only the direct energy requirements, but also the indirect energy inputs needed to produce the capital equipment, operating materials, etc. The report begins with a discussion of the technique of energy accounting, and the merits and limitations of the two principal approaches are compared. These are: 'Process Analysis' (or 'Energy Cost of Materials') and 'Input-Output Analysis' (or 'Energy Cost of Money'). A comparison is made between the energy cost of the tidal and pumped schemes, by both methods of analysis. A 'Best Estimate' is compiled calling on both methods, and this indicates that on an energy cost basis the pumped scheme is three times as expensive as the tidal scheme. Intermediate schemes are feasible, however. There is some evidence that the energy cost of an ore refining process with an initial concentration of 0.007% would be of the same order as that of the pumped seawater scheme. The energy cost of generating electricity using seawater uranium in an SGHWR is compared with the present UK generating system as a whole. (U.K.)

  19. 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

  20. 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...

  1. 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

  2. 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

  3. 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.)

  4. 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

  5. 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

  6. 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

  7. Partitioning in P-T concept

    International Nuclear Information System (INIS)

    Zhang Peilu; Qi Zhanshun; Zhu Zhixuan

    2000-01-01

    Comparison of dry- and water-method for partitioning fission products and minor actinides from the spent fuels, and description of advance of dry-method were done. Partitioning process, some typical concept and some results of dry-method were described. The problems fond in dry-method up to now were pointed out. The partitioning study program was suggested

  8. 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

  9. 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

  10. 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

  11. 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.

  12. 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.)

  13. 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

  14. A Timing-Driven Partitioning System for Multiple FPGAs

    Directory of Open Access Journals (Sweden)

    Kalapi Roy

    1996-01-01

    Full Text Available Field-programmable systems with multiple FPGAs on a PCB or an MCM are being used by system designers when a single FPGA is not sufficient. We address the problem of partitioning a large technology mapped FPGA circuit onto multiple FPGA devices of a specific target technology. The physical characteristics of the multiple FPGA system (MFS pose additional constraints to the circuit partitioning algorithms: the capacity of each FPGA, the timing constraints, the number of I/Os per FPGA, and the pre-designed interconnection patterns of each FPGA and the package. Existing partitioning techniques which minimize just the cut sizes of partitions fail to satisfy the above challenges. We therefore present a timing driven N-way partitioning algorithm based on simulated annealing for technology-mapped FPGA circuits. The signal path delays are estimated during partitioning using a timing model specific to a multiple FPGA architecture. The model combines all possible delay factors in a system with multiple FPGA chips of a target technology. Furthermore, we have incorporated a new dynamic net-weighting scheme to minimize the number of pin-outs for each chip. Finally, we have developed a graph-based global router for pin assignment which can handle the pre-routed connections of our MFS structure. In order to reduce the time spent in the simulated annealing phase of the partitioner, clusters of circuit components are identified by a new linear-time bottom-up clustering algorithm. The annealing-based N-way partitioner executes four times faster using the clusters as opposed to a flat netlist with improved partitioning results. For several industrial circuits, our approach outperforms the recursive min-cut bi-partitioning algorithm by 35% in terms of nets cut. Our approach also outperforms an industrial FPGA partitioner by 73% on average in terms of unroutable nets. Using the performance optimization capabilities in our approach we have successfully partitioned the

  15. 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)

  16. 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

  17. 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.)

  18. 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.)

  19. 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

  20. Uranium guidebook for the Paradox Basin, Utah and Colorado

    International Nuclear Information System (INIS)

    Anon.

    1978-01-01

    Various data concerning uranium production and reserves of the Paradox Basin are compiled herein. Current production from 2 Utah mills and 1 Colorado mill is estimated at 5.4 million pounds of U 3 O 8 . An overview of uranium mining, geology, tectonics, and types of ore deposits is presented. Detailed description of the 11 mining districts and 21 mining areas are included. Detailed maps and exploration guides are included as assistance to evaluating and seeking new uranium deposits

  1. Internal dosimetry and radiotoxicity of long-lived uranium isotopes

    International Nuclear Information System (INIS)

    Jacobi, W.

    1980-03-01

    The dose to relevant tissues and the effective dose equivalent by ingestion and inhalation of uranium compounds are evaluated on the basis of the new metabolic and dosimetric models recommended by ICRP. Applying these dose factors annual limits for intake of these compounds by workers are derived. Finally the natural uranium exposure of the population is described. From the measured natural U-content of body tissues dose factors for the dietary intake of uranium can be estimated. (orig.) [de

  2. Uranium reserves and exploration activity

    International Nuclear Information System (INIS)

    Meehan, R.J.

    1975-01-01

    The strategy that ERDA plans to employ regarding resource appraisal is outlined. All types of uranium occurrences will be evaluated as sources of domestic ore reserves. Industry's exploration efforts will be compiled. These data will include information on land acquisition and costs, footage drilled and costs, estimates of exploration activities and expenditures, exploration for non-sandstone deposits, exploration in non-established areas, and foreign exploration plans and costs. Typical data in each of these areas are given

  3. The concentrations of uranium in marine organisms

    Energy Technology Data Exchange (ETDEWEB)

    Matsuba, Mitsue; Ishii, Toshiaki; Nakahara, Motokazu; Nakamura, Ryoichi; Watabe, Teruhisa; Hirano, Shigeki [National Inst. of Radiological Sciences, Hitachinaka, Ibaraki (Japan). Laboratory for Radioecology

    2000-07-01

    Determination of uranium in sixty-one species of marine organisms was carried out by inductively coupled plasma mass spectrometry to obtain concentration factors and to estimate the internal radiation dose. The concentrations of uranium in soft tissues of marine animals were ranged from 0.077 to 5040 ng/g wet wt. Especially, the branchial heart of cephalopod molluscs showed the specific accumulation of uranium. The concentration factor of the branchial heart of Octopus vulgaris, which indicated the highest value, was calculated to be about 1.6 x 10{sup 3}, comparing with that (3.1 ng/ml) in coastal seawaters of Japan. The concentrations of uranium in hard tissues of marine invertebrates such as clam and sea urchin were similar to those in soft tissues. In contrast, hard tissues like bone, scale, fin, etc. of fishes showed much higher concentrations of uranium than soft tissues like muscle. The concentrations of uranium of twenty-two species of algae were ranged from 2 to 310 ng/g wet wt. Particularly, the brown alga Undaria pinnatifida showed the highest value of the uranium content in the algae and its concentration factor was calculated to be 10{sup 2}. (author)

  4. The concentrations of uranium in marine organisms

    International Nuclear Information System (INIS)

    Matsuba, Mitsue; Ishii, Toshiaki; Nakahara, Motokazu; Nakamura, Ryoichi; Watabe, Teruhisa; Hirano, Shigeki

    2000-01-01

    Determination of uranium in sixty-one species of marine organisms was carried out by inductively coupled plasma mass spectrometry to obtain concentration factors and to estimate the internal radiation dose. The concentrations of uranium in soft tissues of marine animals were ranged from 0.077 to 5040 ng/g wet wt. Especially, the branchial heart of cephalopod molluscs showed the specific accumulation of uranium. The concentration factor of the branchial heart of Octopus vulgaris, which indicated the highest value, was calculated to be about 1.6 x 10 3 , comparing with that (3.1 ng/ml) in coastal seawaters of Japan. The concentrations of uranium in hard tissues of marine invertebrates such as clam and sea urchin were similar to those in soft tissues. In contrast, hard tissues like bone, scale, fin, etc. of fishes showed much higher concentrations of uranium than soft tissues like muscle. The concentrations of uranium of twenty-two species of algae were ranged from 2 to 310 ng/g wet wt. Particularly, the brown alga Undaria pinnatifida showed the highest value of the uranium content in the algae and its concentration factor was calculated to be 10 2 . (author)

  5. Classification of uranium reserves/resources

    International Nuclear Information System (INIS)

    1998-08-01

    Projections of future availability of uranium to meet present and future nuclear power requirements depend on the reliability of uranium resource estimates. Lack of harmony of the definition of the different classes of uranium reserves and resources between countries makes the compilation and analysis of such information difficult. The problem was accentuated in the early 1990s with the entry of uranium producing countries from the former Soviet Union, eastern Europe and China into the world uranium supply market. The need for an internationally acceptable reserve/resource classification system and terminology using market based criteria is therefore obvious. This publication was compiled from participant's contributions and findings of the Consultants Meetings on Harmonization of Uranium Resource Assessment Concepts held in Vienna from 22 to 25 June 1992, and two Consultants Meetings on the Development of a More Meaningful Classification of Uranium Resources held in Kiev, Ukraine on 24-26 April 1995 and 20-23 August 1996. This document includes 11 contributions, summary, list of participants of the Consultants Meetings. Each contribution has been indexed and provided with an abstract

  6. Jabiluka gold-uranium project

    International Nuclear Information System (INIS)

    1988-01-01

    The Jabiluka gold-uranium deposit, 230km east of Darwin in the Alligator Rivers Region of the Northern Territory, was discovered by Pancontinental Mining Limited in 1971. Jabiluka, with reserves in excess of 200,000 tonnes of contained U 3 O 8 in two deposits 500 metres apart, is the world's largest high grade uranium deposit and also contains nearly 12 tonnes of gold. It is proposed that only the larger deposit, Jabiluka II will be mined - by underground extraction methods, and that 275,000 tonnes of ore per year will be mined and processed to produce 1,500 tonnes of U 3 O 8 and up to 30,000 oz of gold. The revenue from the uranium sales is estimated to be of the order of A$100 million per year at A$30/lb. By the end of 1982 all necessary mining and environmental approvals had been obtained and significant marketing progress made. With the Australian Labor Party winning Commonwealth Government in the 1983 election, Pancontinental's permission to seek sales contracts was withdrawn and development of the Jabiluka deposit ceased. Jabiluka remains undeveloped - awaiting a change in Australian Government policy on uranium. figs., maps

  7. Partitioning sparse rectangular matrices for parallel processing

    Energy Technology Data Exchange (ETDEWEB)

    Kolda, T.G.

    1998-05-01

    The authors are interested in partitioning sparse rectangular matrices for parallel processing. The partitioning problem has been well-studied in the square symmetric case, but the rectangular problem has received very little attention. They will formalize the rectangular matrix partitioning problem and discuss several methods for solving it. They will extend the spectral partitioning method for symmetric matrices to the rectangular case and compare this method to three new methods -- the alternating partitioning method and two hybrid methods. The hybrid methods will be shown to be best.

  8. World uranium supply and demand

    International Nuclear Information System (INIS)

    Patterson, J.A.

    1980-01-01

    The role of nuclear energy is under increasing scrutiny and uncertainty. None the less, there will be an increasing need for expansion of uranium supply to fuel committed reactors. Longer-term demand projections are very uncertain. Improved knowledge of the extent of world resources and their availability and economics is needed to support planning for reactor development, especially for breeder reactors, and for fuel-cycle development, especially enrichment, and reprocessing and recycle of uranium and plutonium. Efforts to date to estimate world uranium resources have been very useful but have largely reflected the state of available knowledge for the lower cost resources in regions that have received considerable exploration efforts. The IUREP evaluation of world resources provides an initial speculative estimate of world resources, including areas not previously appraised. Projections of long-range supply from the estimated resources suggest that the high-growth nuclear cases using once-through cycle may not be supportable for very long. However, additional effort is needed to appraise and report more completely and consistently on world resources, the production levels attainable from these resources, and the economic and price characteristics of such production. (author)

  9. PAQ: Partition Analysis of Quasispecies.

    Science.gov (United States)

    Baccam, P; Thompson, R J; Fedrigo, O; Carpenter, S; Cornette, J L

    2001-01-01

    The complexities of genetic data may not be accurately described by any single analytical tool. Phylogenetic analysis is often used to study the genetic relationship among different sequences. Evolutionary models and assumptions are invoked to reconstruct trees that describe the phylogenetic relationship among sequences. Genetic databases are rapidly accumulating large amounts of sequences. Newly acquired sequences, which have not yet been characterized, may require preliminary genetic exploration in order to build models describing the evolutionary relationship among sequences. There are clustering techniques that rely less on models of evolution, and thus may provide nice exploratory tools for identifying genetic similarities. Some of the more commonly used clustering methods perform better when data can be grouped into mutually exclusive groups. Genetic data from viral quasispecies, which consist of closely related variants that differ by small changes, however, may best be partitioned by overlapping groups. We have developed an intuitive exploratory program, Partition Analysis of Quasispecies (PAQ), which utilizes a non-hierarchical technique to partition sequences that are genetically similar. PAQ was used to analyze a data set of human immunodeficiency virus type 1 (HIV-1) envelope sequences isolated from different regions of the brain and another data set consisting of the equine infectious anemia virus (EIAV) regulatory gene rev. Analysis of the HIV-1 data set by PAQ was consistent with phylogenetic analysis of the same data, and the EIAV rev variants were partitioned into two overlapping groups. PAQ provides an additional tool which can be used to glean information from genetic data and can be used in conjunction with other tools to study genetic similarities and genetic evolution of viral quasispecies.

  10. Plutonium in uranium deposits

    International Nuclear Information System (INIS)

    Curtis, D.; Fabryka-Martin, J.; Aguilar, R.; Attrep, M. Jr.; Roensch, F.

    1992-01-01

    Plutonium-239 (t 1/2 , 24,100 yr) is one of the most persistent radioactive constituents of high-level wastes from nuclear fission power reactors. Effective containment of such a long-lived constituent will rely heavily upon its containment by the geologic environment of a repository. Uranium ore deposits offer a means to evaluate the geochemical properties of plutonium under natural conditions. In this paper, analyses of natural plutonium in several ores are compared to calculated plutonium production rates in order to evaluate the degree of retention of plutonium by the ore. The authors find that current methods for estimating production rates are neither sufficiently accurate nor precise to provide unambiguous measures of plutonium retention. However, alternative methods for evaluating plutonium mobility are being investigated, including its measurement in natural ground waters. Preliminary results are reported and establish the foundation for a comprehensive characterization of plutonium geochemistry in other natural environments

  11. 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

  12. 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.

  13. Uranium in Canada: 1982 assessment of supply and requirements

    International Nuclear Information System (INIS)

    1983-09-01

    Estimates of Canada's uranium resources for 1982 remained essentially unchanged from those of 1980. However, the economic conditions facing the industry have changed greatly during the past few years as production costs continued to rise without corresponding increases in uranium prices. As a result, a smaller portion of Canada's uranium resources is of current economic interest. Total resources amount to 573 000 tonnes of uranium. Just over 10% of this uranium will be required domestically during the next 30 years to fuel the more than 15 000 megawatts of nuclear power capacity now operating or committed for operation in Canada by 1993. In 1982 seven uranium producers in Canada, directly employing 4800 people, produced concentrates containing 8075 tonnes of uranium. Based on currently committed expansion plans, Canada's projected annual production capability could grow to some 12 000 tonnes of uranium by 1986. Canadian producers shipped 7643 tonnes of uranium valued at some $838 millon in 1982. As of January 1, 1983, outstanding uranium export commitments amounted to 60 000 tonnes or roughly 10% of the total Canadian uranium resources mentioned above. Japan has been Canada's most important single customer in the past decade, receiving about 34% of Canada's total exports since 1972. Most of the remaining exports have gone to the European Economic Community (33%), other countries in Western Europe (18%), and the United States (15%). Substantial efforts in uranium exploration that have been continued, especially in northern Saskatchewan, where two-thirds of the $71 million total exploration expenditures of 1982 were incurred. This continued effort has led to the discovery of a number of important deposits over the past few years which could be developed if market conditions improve. It is estimated that total Canadian production capability could reach 15 000 tonnes of uranium annually by the mid-1990s

  14. World uranium production and demand: A review

    International Nuclear Information System (INIS)

    Tauchid, M.; Mueller Kahle, E.

    1993-01-01

    Despite the growing public concern on the use of nuclear energy, nuclear power generation capacity in the world is expected to follow a modest, but positive growth at least during the next two decades. Uranium production needed to fuel these reactors has been below demand since 1985. The WOCA production figure for 1991 is in the order of 27,000 tonnes U which is 39% below the peak production of 1980. With the exception of Australia, all other countries produced less uranium than in the previous year. It is expected that the production figure for 1992 will shrink even further to about 23,000 tonnes U. In-situ leaching uranium production contributed about 16% to the 1991 world production figure, most of which came from Eastern Europe and Central Asia. With the closing of a number of production facilities the relative contribution of in-situ leaching to the world uranium production is expected to grow. Only about 60% of WOCA's reactor related uranium demand for 1991 was supplied from its own production. The remaining 40% was filled from existing inventories and imports from the Russian Federation and China. The estimated gap between the world uranium production and reactor related demand for 1991 is in the order 10,900 tones U or 19.7%. The cumulative requirement for the world reactor related demand to the year 2010 has been estimated to be about 1,270,000 tonnes U. (author). 6 refs, 10 figs

  15. 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

  16. World uranium resources, production and demand

    International Nuclear Information System (INIS)

    Lindholm, I.

    1988-01-01

    Reasonably assured resources of uranium in WOCA (World Outside the Centrally Planned Economies Area) countries recoverable at less than US $80/kg U increased by about 9% between 1983 and 1985 and currently stand at 1.5 million tonnes. Uranium also exists in significant quantities in higher cost resources or in less known resources. However, the annual exploration expenditure is less than 20% that of the 1979 level. Uranium production in WOCA countries was higher than consumption during the period 1965 to 1984 and considerable stocks were accumulated. However, the production figures for 1985 were estimated to be slightly less than those of consumption. Production from centres now on stand-by or new centres will probably be necessary around 1990. Analysis of the longer term production possibilities indicates that uranium supplies will probably not be constrained by an ultimate resource adequacy. Constraints, if any, are more likely to be of political nature. (author). 11 figs, 1 tab

  17. 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.

  18. 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.)

  19. 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...

  20. Stream sediment geochemical surveys for uranium

    International Nuclear Information System (INIS)

    Price, V.; Ferguson, R.B.

    1979-01-01

    Stream sediment is more universally available than ground and surface waters and comprises the bulk of NURE samples. Orientation studies conducted by the Savannah River Laboratory indicate that several mesh sizes can offer nearly equivalent information. Sediment is normally sieved in the field to pass a 420-micrometer screen (US Std. 40 mesh) and that portion of the dried sediment passing a 149-micrometer screen (US Std. 100 mesh) is recovered for analysis. Sampling densities usually vary with survey objectives and types of deposits anticipated. Principal geologic features that can be portrayed at a scale of 1:250,000, such as major tectonic units, plutons, and pegmatite districts, are readily defined using a sampling density of 1 site per 5 square miles (13 km 2 ). More detailed studies designed to define individual deposits require greater sampling density. Analyses for elements known to be associated with uranium in a particular mineral host may be used to estimate the relative proportion of uranium in several forms. For example, uranium may be associated with thorium and cerium in monazite, and with zirconium and hafnium in zircon. Readily leachable uranium may be adsorbed to trapped in oxide coatings on mineral particles. Soluble or mobile uranium may indicate an ore source, whereas uranium in monazite or zircon is not likely to be economically attractive. Various schemes may be used to estimate for form of uranium in a sample. Simple elemental ratios are a useful first approach. Multiple ratios and subtractive formulas empirically designed to account for the presence of particular minerals are more useful. Residuals calculated from computer-derived regression equations or factor scores appear to have the greatest potential for locating uranium anomalies

  1. Radiological hazards to uranium miners

    International Nuclear Information System (INIS)

    1990-05-01

    The purpose of the present document is to review and assess the occupational hazards to uranium miners in Canada. Amendments to regulations set the maximum permissible dose to uranium miners at 50 mSv per year. Uranium miners are exposed to radon and thoron progeny, external gamma radiation and long-lived alpha-emitting radionuclides in dust. The best estimate for the lifetime risk of inhaled radon progeny is about 3 x 10 -4 lung cancers per WLM for the average miner, with a range of uncertainty from about 1 -6 x 10 -4 per WLM. This central value is nearly twice as high as that recommended by the ICRP in 1981. The probability of serious biological consequences following exposure to external gamma rays is currently under review but is expected to be in the range of 3 - 6 x 10 -2 Sv -1 . Dosimetric calculations indicate that the stochastic risks per WLM of thoron progeny are about one-third of those for radon progeny. The annual limits on intake of inhaled ore dusts recommended by the ICRP are probably too low by at least a factor of two for the type of ore and dust normally encountered in underground uranium mines in Ontario; this is due in part to the fact that the average diameter of these dusts is five times greater than the value used by the ICRP. Radiological exposures of uranium miners in Canada were reviewed. The biological impact of these exposures were compared with those of conventional accidents on the basis of the years of normal life expectancy that are lost or seriously impaired due to occupational hazards. The objectives in considering all occupational risks are to reduce the total risk from all causes and to use funds spent for health protection as effectively as possible

  2. State of uranium and radium radionuclides in the soil medium

    International Nuclear Information System (INIS)

    Vojnikova, E.V.; Sokolik, G.A.; Ovsyannikova, S.V.; Popenya, M.V.

    2010-01-01

    The reserves of migratory active, potentially mobile and potentially biologically available forms of uranium and radium in the mineral and organic soils of Belarus have been established. The uranium and radium species in the soil pore waters have been also studied. The received data makes possible the estimation of the radionuclide ability to participate in the processes of biogeochemical migration in terrestrial ecosystems. (authors)

  3. Partitioning and transmutation (P and T) 1997. Status report

    International Nuclear Information System (INIS)

    Enarsson, Aasa; Landgren, A.; Liljenzin, J.O.; Skaalberg, M.; Spjuth, L.; Gudowski, W.; Wallenius, J.

    1998-05-01

    Research on and the evaluation of partitioning and transmutation are currently in progress in many industrial countries due to its potential as a long-term, sustainable energy source with low environmental impact and due to its ability to destroy many long-lived nuclides. The cost of the research and development work on partitioning and transmutation is considered to be so great that international co-operation is required. With respect to Sweden, we recommend a balanced research work on both partitioning and transmutation technology. Within the area of partitioning, it is above all a question of locating new reagents which can be used to simplify the necessary partitioning processes and minimize the losses. The requirements with respect to high selectivity and minor losses will be significantly higher in a recirculating system based on transmutation than in the reprocessing facilities of today where only uranium and plutonium are recovered. If the utilized reagents can be easily destroyed, by dry or wet incineration and conversion into non-complex gaseous chemical compounds, this will open up good opportunities for the recovery of the radionuclides. From a purely technical standpoint, it would seem that a combination of different types of reactor systems would give the best possible transmutation efficiency. While existing light water reactors can be utilized for increased plutonium incineration, there is currently consensus about the view that reactors with high-energy neutrons are necessary to achieve a sufficiently high transmutation efficiency for neptunium, americium, curium and certain fission products. By allowing an accelerator-based neutron source to drive a subcritical heavy metal-cooled reactor, the potential for transmutation of fission products is increased, at the same time that satisfactory safety margins are achieved for certain fuel types with a low share of delayed neutrons and a high heat conductivity. Regardless of what types of systems are

  4. Partitioning and transmutation (P and T) 1997. Status report

    Energy Technology Data Exchange (ETDEWEB)

    Enarsson, Aasa; Landgren, A.; Liljenzin, J.O.; Skaalberg, M.; Spjuth, L. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Nuclear Chemistry; Gudowski, W.; Wallenius, J. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Nuclear and Reactor Physics

    1998-05-01

    Research on and the evaluation of partitioning and transmutation are currently in progress in many industrial countries due to its potential as a long-term, sustainable energy source with low environmental impact and due to its ability to destroy many long-lived nuclides. The cost of the research and development work on partitioning and transmutation is considered to be so great that international co-operation is required. With respect to Sweden, we recommend a balanced research work on both partitioning and transmutation technology. Within the area of partitioning, it is above all a question of locating new reagents which can be used to simplify the necessary partitioning processes and minimize the losses. The requirements with respect to high selectivity and minor losses will be significantly higher in a recirculating system based on transmutation than in the reprocessing facilities of today where only uranium and plutonium are recovered. If the utilized reagents can be easily destroyed, by dry or wet incineration and conversion into non-complex gaseous chemical compounds, this will open up good opportunities for the recovery of the radionuclides. From a purely technical standpoint, it would seem that a combination of different types of reactor systems would give the best possible transmutation efficiency. While existing light water reactors can be utilized for increased plutonium incineration, there is currently consensus about the view that reactors with high-energy neutrons are necessary to achieve a sufficiently high transmutation efficiency for neptunium, americium, curium and certain fission products. By allowing an accelerator-based neutron source to drive a subcritical heavy metal-cooled reactor, the potential for transmutation of fission products is increased, at the same time that satisfactory safety margins are achieved for certain fuel types with a low share of delayed neutrons and a high heat conductivity. Regardless of what types of systems are

  5. Adsorption of dissolved uranium from well water. Part I

    International Nuclear Information System (INIS)

    Jasper, S.; Oldham, W.K.

    1982-01-01

    This study was undertaken in response to a request from the provincial Ministry of Health, to evaluate several methods for removal of uranium from well water in the Okanagan Valley of British Columbia. The naturally occurring uranium levels in some of these wells is above 100 ppb, and as the drinking water standard for uranium is 20 ppb, it has become necessary to develop an efficient, easily operated system to reduce uranium concentration. This study comprises the first step in this process by selecting the most appropriate adsorbent and estimating its efficiency and capacity

  6. Measurements of uranium in soils and small mammals

    International Nuclear Information System (INIS)

    Miera, F.R. Jr.

    1980-12-01

    The objective of this study was to evaluate the bioavailability of uranium to a single species of small mammal, Peromyscus maniculatus rufinus (Merriam), white-footed deer mouse, from two different source terms: a Los Alamos National Laboratory dynamic weapons testing site in north central New Mexico, where an estimated 70,000 kg of uranium have been expended over a 31-y period; and an inactive uranium mill tailings pile located in west central New Mexico near Grants, which received wastes over a 5-y period from the milling of 2.7 x 10 9 kg of uranium ore

  7. Measurements of uranium in soils and small mammals

    Energy Technology Data Exchange (ETDEWEB)

    Miera, F.R. Jr.

    1980-12-01

    The objective of this study was to evaluate the bioavailability of uranium to a single species of small mammal, Peromyscus maniculatus rufinus (Merriam), white-footed deer mouse, from two different source terms: a Los Alamos National Laboratory dynamic weapons testing site in north central New Mexico, where an estimated 70,000 kg of uranium have been expended over a 31-y period; and an inactive uranium mill tailings pile located in west central New Mexico near Grants, which received wastes over a 5-y period from the milling of 2.7 x 10/sup 9/ kg of uranium ore.

  8. Calculation of gamma ray exposure rates from uranium ore bodies

    International Nuclear Information System (INIS)

    Thomson, J.E.; Wilson, O.J.

    1980-02-01

    The planning of operations associated with uranium mines often requires that estimates be made of the exposure rates from various ore bodies. A straight-forward method of calculating the exposure rate from an arbitrarily shaped body is presented. Parameters for the calculation are evaluated under the assumption of secular equilibrium of uranium with its daughters and that the uranium is uniformly distributed throughout an average soil mixture. The spectral distribution of the emitted gamma rays and the effect of air attenuation are discussed. Worked examples are given of typical situations encountered in uranium mines

  9. International Uranium Resources Evaluation Project (IUREP) national favourability studies: Thailand

    International Nuclear Information System (INIS)

    1977-08-01

    Thailand is a country with an area of 514?000 square kilometres situated in the centre of continental south-east Asia, The geology of Thailand is very varied with sedimentary formations ranging from Cambrian to Quaternary in age and including sandstones, shales, limestones of many varieties. Among the igneous rocks, granites are very important and rhyolites, tuffs diorites, basalts and ultrabasic rocks also exist. Tin is the most important mineral occurrence. Available information on the geology and mineral resources suggests that the country may contain significant resources of radioactive minerals. Favourable potential host types are; 1) uranium and thorium in monazite in beach sands and tin placer deposits; 2) uranium in sandstones, principally in Jurassic sandstones of the Khorat Plateau; 3) uranium in Tertiary lignite deposits; 4) uranium in veins in granites; 5) uranium related to fluorite deposits; 6) uranium in black shales and phosphates. Uranium mineralization in sedimentary rocks at Phu Wieng was discovered in 1970. The area has been radiometrically grid mapped and limited shallow drilling has shown continuity.of the narrow, carbonaceous, conglomeratic sandstone host bed. No uranium reserves or resources can be stated at the present time, but the favourable geology of the Khorat Plateau, the known uranium occurrence and the very small exploration coverage is possibly indicative of a good future potential. The Speculative Potential is estimated to be between 1000 and 10,000 tonnes uranium. (author)

  10. DYNAMIC PROPERTIES OF SHOCK LOADED THIN URANIUM FOILS

    International Nuclear Information System (INIS)

    Robbins, D.L.; Kelly, A.M.; Alexander, D.J.; Hanrahan, R.J.; Snow, R.C.; Gehr, R.J.; Rupp, Ted Dean; Sheffield, S.A.; Stahl, D.B.

    2001-01-01

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

  11. The uranium market - economic and political factors

    International Nuclear Information System (INIS)

    Price, T.

    1978-01-01

    This is an article by the Secretary General of the Uranium Institute, who is also Head of the Reactor Development Divisiion, UKAE, Winfrith. Estimates are given of the demand for uranium up to 1990 and factors likely to affect it are considered. Estimates of production up to 1985 show that it should be able to keep pace with demand until late in the eighties. The world potential for production after 1985 is examined from the viewpoint of resource availability exploration, price and government policies. (author)

  12. Extraction behavior of uranium(VI) with polyurethane foam

    International Nuclear Information System (INIS)

    Tingchia Huang; Donghwang Chen; Muchang Shieh; Chingtsven Huang

    1992-01-01

    The extraction of uranium(VI) from aqueous solution with polyether-based polyurethane (PU) foam was studied. The effects of the kinds and concentrations of nitrate salts, uranium(VI) concentration, temperature, nitric acid concentration, pH, the content of poly(ethylene oxide) in the polyurethane foam, and the ratio of PU foam weight and solution volume on the extraction of uranium(VI) were investigated. The interferences of fluoride and carbonate ions on the extraction of uranium(VI) were also examined, and methods to overcome both interferences were suggested. It was found that no uranium was extracted in the absence of a nitrate salting-out agent, and the extraction behaviors of uranium(IV) with polyurethane foam could be explained in terms of an etherlike solvent extraction mechanism. In addition, the percentage extraction of a multiple stage was also estimated theoretically

  13. Review of international classification systems for uranium resources

    International Nuclear Information System (INIS)

    Wang Wenyou

    2007-01-01

    The two primary classification systems for uranium resources in common use in the whole world are described. These uranium resource classification systems were developed under two distinct philosophies, it implies two very different processes, criteria, terms and definitions from which the systems evolved and were implemented. However, the two primary systems are all based on two considerations: the degree of geological confidence and the degree of economic attractiveness based on cost of producing the resource. The uranium resource classification methods currently used in most major uranium producing countries have all a bearing on the two aforesaid classification systems. The disparity exists only in the way or practice of classifying and estimating the uranium resources for reasons of different political and economical systems in various countries. The harmonization of these resource classification systems for uranium can be realized with the economic integration on a global scale. (authors)

  14. Distribution of natural uranium in groundwater around Kudankulam

    International Nuclear Information System (INIS)

    Selvi, B.S.; Vijayakumar, B.; Rana, B.K.; Ravi, P.M.

    2016-01-01

    A systematic study was carried out to estimate the uranium concentration in the ground water around Kudankulam in Southern Tamil Nadu. The uranium concentration in ground water varies from 0.2 to 6.6 μg/l, with a mean value of 2.0 μg/l. The Quantalase uranium analyzer was used to measure the uranium concentration. These groundwater samples were analyzed for the water quality parameters such as pH, conductance, total dissolved solids (TDS), salinity, chloride, and sulfate. An attempt has been made to correlate the uranium concentration with the water quality parameters. It is observed that conductance, TDS, salinity, chloride, and sulfate show positive correlation with uranium concentration. (author)

  15. 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

  16. 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

  17. 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)

  18. Energy partition in nuclear fission

    International Nuclear Information System (INIS)

    Ruben, A.; Maerten, H.; Seeliger, D.

    1990-01-01

    A scission point model (two spheroid model TSM) including semi-empirical temperature-dependent shell correction energies for deformed fragments at scission is presented. It has been used to describe the mass-asymmetry-dependent partition of the total energy release on both fragments from spontaneous and induced fission. Characteristic trends of experimental fragment energy and neutron multiplicity data as function of incidence energy in the Th-Cf region of fissioning nuclei are well reproduced. Based on model applications, information on the energy dissipated during the descent from second saddle of fission barrier to scission point have been deduced. (author). 39 refs, 13 figs

  19. Uranium supply analysis: Evolution of concepts

    International Nuclear Information System (INIS)

    Williams, R.M.

    1998-01-01

    Considerable effort has been expended during the last 15 years to develop improved methods of analysing current and future mineral supply, with the objectives of providing illustrations of mineral supply possibilities that are more meaningful and easily understood. Significant contributions toward these objectives have been made in the course of studies on world uranium supply, which took place in the 1970s prompted by concern about the future availability of mineral fuels. The Nuclear Energy Agency (NEA) of the Organization for Economic Co-operation and Development (OECD), and the International Atomic Energy Agency (IAEA) have played a key role in these efforts, through their biennial assessments of world uranium supply. There has been a pronounced shift in emphasis in the NEA/IAEA assessments away from resource estimates by themselves as a measure of supply, because of a growing awareness that, in isolation, resource estimates cannot provide a truly meaningful illustration of uranium availability. Indeed, resource estimates taken out of context can lead to false conclusions about resource adequacy. Successive NEA/IAEA studies have made increasing use of projections of production capability that show the possible availability of uranium from different categories of resources and production centres over specified time-frames. It is believed that such supply scenarios provide a much more meaningful illustration of uranium availability for both short and long-term planning purposes. As part of the effort to introduce such an approach to NEA/IAEA uranium supply analyses, the IAEA has prepared a manual which provides general guidelines for preparing projections of production capability. It is hoped that these efforts will contribute to a better understanding of the constraints on uranium supply and to the wider acceptance of projections of production capability as measures of resource adequacy. (author)

  20. Financing the Ranger uranium project

    International Nuclear Information System (INIS)

    Hodge, S.J.; Miskelly, N.

    1983-01-01

    Construction of the Ranger uranium project located 230 km east of Darwin in the Northern Territory commenced in January 1979. Energy Resources of Australia Ltd was incorporated in February 1980 to acquire all the rights in the project. The total cost to ERA of these rights was $407 million. In October 1980 ERA'S cash requirements were estimated to be $553 million. Overseas participants (power utilities who had agreed to purchase uranium yellowcake under contract) arranged to take up 25% of the equity capital, Peko-Wallsend Ltd and EZ Industries Ltd were allotted 30.5% each and 14% was issued to Australian residents. The loan and equity financing arrangements required the successful resolution of many complex and interlocking factors, including technical and economic feasibility, agreement with aboriginal interests, compliance with Government policies and securing of sales contracts

  1. Uranium Resources, production and demand

    International Nuclear Information System (INIS)

    1988-01-01

    Periodic assessments of world uranium supply and demand have been conducted by the OECD Nuclear Energy Agency (NEA) and the International Atomic Energy Agency (IAEA) since the mid 1960s. Published every two years, the report URANIUM RESOURCES, PRODUCTION AND DEMAND, commonly referred to as the RED BOOK, has become an essential reference document for nuclear planners and policy makers in the international nuclear community. The latest Red Book, published in 1988, was based on data collected mainly in early 1987. Most of the data for 1987 were therefore provisional. The STATISTICAL UPDATE 1988 provides updated 1987 data collected in 1988 and provisional data for 1988. The publication, which covers OECD Countries and gives Secretariat estimates for the rest of the World Outside Centrally Planned Economies (WOCA), is being issued every second year, between publications of more complete Red Books

  2. Uranium, resources, production and demand

    International Nuclear Information System (INIS)

    1986-01-01

    Periodic assessments of world uranium supply have been conducted by the OECD Nuclear Energy Agency (NEA) and the International Atomic Energy Agency (IAEA) since the mid 1960s. Published every two years, the report Uranium resources, production and demand, commonly referred to as the red book, has become an essential reference document for nuclear planners and policy makers in the international nuclear community. The latest red book, published in 1986, was based on data collected mainly in early 1985. Most of the data for 1985 were therefore provisional. The statistical update 1986 provides updated 1985 data collected in 1986 and provisional data for 1986. This is the first time such an annual update of key Red Book statistical data has been prepared. This year it covers only OECD countries with a secretariat estimate for the rest of Woca

  3. Partial Key Grouping: Load-Balanced Partitioning of Distributed Streams

    OpenAIRE

    Nasir, Muhammad Anis Uddin; Morales, Gianmarco De Francisci; Garcia-Soriano, David; Kourtellis, Nicolas; Serafini, Marco

    2015-01-01

    We study the problem of load balancing in distributed stream processing engines, which is exacerbated in the presence of skew. We introduce PARTIAL KEY GROUPING (PKG), a new stream partitioning scheme that adapts the classical “power of two choices” to a distributed streaming setting by leveraging two novel techniques: key splitting and local load estimation. In so doing, it achieves better load balancing than key grouping while being more scalable than shuffle grouping. We test PKG on severa...

  4. 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

  5. Partitioning of copy-number genotypes in pedigrees

    Directory of Open Access Journals (Sweden)

    Andelfinger Gregor U

    2010-05-01

    Full Text Available Abstract Background Copy number variations (CNVs and polymorphisms (CNPs have only recently gained the genetic community's attention. Conservative estimates have shown that CNVs and CNPs might affect more than 10% of the genome and that they may be at least as important as single nucleotide polymorphisms in assessing human variability. Widely used tools for CNP analysis have been implemented in Birdsuite and PLINK for the purpose of conducting genetic association studies based on the unpartitioned total number of CNP copies provided by the intensities from Affymetrix's Genome-Wide Human SNP Array. Here, we are interested in partitioning copy number variations and polymorphisms in extended pedigrees for the purpose of linkage analysis on familial data. Results We have developed CNGen, a new software for the partitioning of copy number polymorphism using the integrated genotypes from Birdsuite with the Affymetrix platform. The algorithm applied to familial trios or extended pedigrees can produce partitioned copy number genotypes with distinct parental alleles. We have validated the algorithm using simulations on a complex pedigree structure using frequencies calculated from a real dataset of 300 genotyped samples from 42 pedigrees segregating a congenital heart defect phenotype. Conclusions CNGen is the first published software for the partitioning of copy number genotypes in pedigrees, making possible the use CNPs and CNVs for linkage analysis. It was implemented with the Python interpreter version 2.5.2. It was successfully tested on current Linux, Windows and Mac OS workstations.

  6. Age, sedimentary environments, and other aspects of sandstone and related host rocks for uranium deposits

    International Nuclear Information System (INIS)

    1983-01-01

    Project II of the Uranium Geology Working Group was assigned to the study of sedimentary basins and sandstone - type uranium deposits. About 40% of the worlds's uranium resources are contained in sandstone-type deposits, which has led to extensive research. The research was carried out mainly by correspondence, and the results reported by 21 geologists from 10 nations are summarized in this report. It investigated five topics dealing with important aspects of the geology of uranium ores in sandstone host formations: age of host rock; partitioning of uranium between continental and marine sediments; latitude limitation on formation of sandstone deposits; effect of rock formation dip on sandstone ores; usefulness of stable isotope and fluid inclusion studies. The results of studies on these subjects form part of a wider programme of the Working Group, whose final results will be presented at the 27th International Geological Congress in Moscow in 1984

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

    International Nuclear Information System (INIS)

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

    1997-07-01

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

  8. Re-examining uranium supply and demand: New insights

    International Nuclear Information System (INIS)

    Kahouli, Sondes

    2011-01-01

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

  9. Re-examining uranium supply and demand: New insights

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-01-15

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

  10. Re-examining uranium supply and demand. New insights

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-01-15

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

  11. Scheduling Driven Partitioning of Heterogeneous Embedded Systems

    DEFF Research Database (Denmark)

    Pop, Paul; Eles, Petru; Peng, Zebo

    1998-01-01

    In this paper we present an algorithm for system level hardware/software partitioning of heterogeneous embedded systems. The system is represented as an abstract graph which captures both data-flow and the flow of control. Given an architecture consisting of several processors, ASICs and shared...... busses, our partitioning algorithm finds the partitioning with the smallest hardware cost and is able to predict and guarantee the performance of the system in terms of worst case delay....

  12. Lift of dilogarithm to partition identities

    International Nuclear Information System (INIS)

    Terhoeven, M.

    1992-11-01

    For the whole set of dilogarithm identities found recently using the thermodynamic Bethe-Ansatz for the ADET series of purely elastic scattering theories we give partition identities which involve characters of those conformal field theories which correspond to the UV-limits of the scattering theories. These partition identities in turn allow to derive the dilogarithm identities using modular invariance and a saddle point approximation. We conjecture on possible generalizations of this correspondance, namely, a lift from dilogarithm to partition identities. (orig.)

  13. 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

  14. 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

  15. 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

  16. 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.)

  17. 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)

  18. 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

  19. 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

  20. 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