Innovative developments in uranium separation and concentration technology abroad

International Nuclear Information System (INIS)

Liang Jinlong; Zhou Mingsheng; Fang Wei; Sun Yuxiang

2014-01-01

Significance of deeply study the innovative developments in Uranium separation and concentration technology abroad was discussed. Development history and innovativeness of eight species of key equipments for separation and concentration were summarized for the first time. Principle and application of seven Uranium separation and concentration technology were analyzed systematically. It is expounded in the paper that high parameter, intelligent and low carbon were three development trends of Uranium separation and concentration technology. (authors)

Activity concentration of uranium in groundwater from uranium mineralized areas and its neighborhood

International Nuclear Information System (INIS)

Arabi, S.A.; Funtua, I.I.; Dewu, B.B.M.; Alagbe, S.A.; Garba, M.L.; Kwaya, M.Y.; Baloga, A.D.

2013-01-01

Uranium mineralization in parts of northeastern Nigeria necessitated its exploration during early eighties by the Nigeria Uranium Mining Company (NUMCO) which was later abandoned. During their course of decay, uranium isotopes pass through radioactive decay stage and eventually into stable isotope of lead. The course of concern for soluble uranium in groundwater especially from the mineralized areas include ionizing radiation, chemical toxicity and reproductive defects for which ingested uranium has been implicated to have caused. This study is aimed at assessing the levels of concentration of uranium in groundwater to ascertain its compliance with the World Health Organization's (WHO) and the United State Environmental Protection Agency's (EPA) guideline for uranium in drinking water. Thirty five groundwater samples were collected using EPA's groundwater sampling protocol and analyzed at the Department of Geology, University of Cape Town using an Inductively Coupled Plasma Mass Spectrometric (ICP-MS) technique. Significant finding of this work was that there is radiological contamination of groundwater in the area. There is also an indication that the extent of radiological contamination is not much within the mineralized zones, therefore, there is likelihood that groundwater has acted as a medium of transporting and enhancing uranium in groundwater in an environment away from that of origin. About 5.7 % of the samples studied had uranium concentration above WHO and EPA's maximum contaminant level of 30 μg/L which is a major concern for inhabitants of the area. It was also apparent that radiological contamination at the southwestern part of the study area extends into the adjacent sheet (sheet 152). Uranium concentration above set standards in those areas might have originated from rocks around established mineralized zones but was transported to those contaminated areas by groundwater that leaches across the host rock and subsequently mobilizing soluble uranium

Anion analysis in uranium more concentrates by ion chromatography

International Nuclear Information System (INIS)

Badaut, V.

2009-01-01

In the present exploratory study, the applicability of anionic impurities or attributing nuclear material to a certain chemical process or origin has been investigated. Anions (e.g., nitrate, sulphate, fluoride, chloride) originate from acids or salt solutions that are used for processing of solutions containing uranium or plutonium. The study focuses on uranium ore concentrates ('yellow cakes') originating from different mines. Uranium is mined from different types of ore body and depending on the type of rock, different chemical processes for leaching, dissolving and precipitating the uranium need to be applied. Consequently, the anionic patterns observed in he products of these processes (the 'ore concentrates') are different. The concentrations of different anionic species were measured by ion chromatography using conductivity detection. The results show clear differences of anion concentrations and patterns between samples from different uranium mines. Besides this, differences between sampling campaigns n a same mine were also observed indicating that the uranium ore is not homogeneous in a mine. These within-mine variations, however, were smaller than the between-mine variations. (author)

Analysis of uranium concentrates by atomic-absorption spectrometry

International Nuclear Information System (INIS)

Naeem, M.; Capdevila, C.; Alduan, F.A.

1977-01-01

The determination of As, Ca, Fe, Mo and V in uranium concentrates, removing the bulk of the uranium matrix by extracting with tributyl phosphate in hexane has been tried. No interferences were found due to uranium, sodium, aluminium, sulfates and phosphates. Only for calcium a depressive effect of aluminium and uranium has been found and it is overcome by addition of lanthanum. Air-acetylene flame for Fe, Ca and As, and nitrous oxide-acetylene flame for Mo and V have been used. The considered concentration range has been 0.15 - 3% for Ca and Fe, 0.1 -2% for As and 0.1 - 1% for Mo and V. (author) [es

Uranium uptake and accumulation in plants from soil contaminated with uranium in different concentrations

International Nuclear Information System (INIS)

Zhao Luxue; Tang Yongjin; Luo Xuegang

2014-01-01

The plants of Medicago sativa L., Hibiscus esulentus L, Waterspinach, Amaranthus retroflexus and Abutilon theophrasti Medic were employed as the indicator to investigate the uranium uptake and accumulation from soils contaminated with uranium (UO_2 (CH_3COO)_2 · 2H_2O) of 25 mg · kg"-"l, 75 mg · kg"-"1, 125 mg · kg"-"l, 175 mg · kg"-"l respectively, in a pot experiment. The result shows that, U concentration in the aerial part and underground part of the whole plant increased with the rise of uranium concentration in the soils. In the contaminated soils with 25∼125 mg · kg"-"l concentrations of uranium, U content of Medicago sativa L is the highset (6.78 mg · kg"-"l, 61.53 mg · kg"-"l, 74.06 mg · kg"-"l separately). While in the 175 mg · kg"-"l concentration of uranium contaminated soils, U content of Hibiscus esulentus L is the highest (86.72 mg · kg"-"1), which is mainly because of U concentration in its roots have higher level of uranium (388.16 mg · kg"-"l). Comprehensive analysis shows that Medicago sativa L. is a good plant for phytoextraction and Hibiscus esulentus L is a good immobilizing plant for phytoremediation. The results can provide some theoretical basis and technical support for remedying U-contaminated soils in different areas of our country. (authors)

A method of uranium isotopes concentration analysis

International Nuclear Information System (INIS)

Lin Yuangen; Jiang Meng; Wu Changli; Duan Zhanyuan; Guo Chunying

2010-01-01

A basic method of uranium isotopes concentration is described in this paper. The iteration method is used to calculate the relative efficiency curve, by analyzing the characteristic γ energy spectrum of 235 U, 232 U and the daughter nuclide of 238 U, then the relative activity can be calculated, at last the uranium isotopes concentration can be worked out, and the result is validated by the experimentation. (authors)

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

REMOVAL AND CONCENTRATION OF URANIUM FROM WASTE MINE

Directory of Open Access Journals (Sweden)

Elizângela Augusta Santos

2011-01-01

Full Text Available The use of leaching agents, such as sodium citrate and ammonium carbonate, were assessed for the extraction of uranium from one mining residue containing 0.25% U. Concentration techniques such as precipitation and ion exchange were employed to recover the uranium from the leaching liquor. Leaching results showed maximum uranium extraction of about 40% for both reagents. The use 10 mol L-1 NaOH to precipitate the uranium from the leach liquor leads to a recovery of 62%; what was considered not satisfactory. In view of this, resins were used to concentrate the uranium from the liquor and the metal loading obtained at pH 3.9 was higher for the resin DOWEX RPU, whose maximum loading maximum capacity was 148.3 mg g-1, compared to 126.9 mg g-1 presented by the resin IRA 910 U.

A survey of natural uranium concentrations in drinking water supplies in Iran

International Nuclear Information System (INIS)

Alirezazadeh, N.; Garshasbi, N.

2003-01-01

Background: Measurement of background concentration of uranium in drinking water is very important for many reasons, specially, for human health. The uranium concentration in drinking water in many countries is a matter of concern for clinical and radioactive poisoning. Materials and methods: The uranium concentration in drinking water is determined using laser fluorimetric uranium analyzer. For this purpose after sampling, sample handling and sample preserving, sample preparation and treatment for reduction of organic matter, the concentration of uranium is measured. Results: To determine the uranium concentrations in drinking water in Iran, nearly 200 water samples were collected from all sources supplying drinking water in 21 provincial centers in the country. The wells were found to be the main source for drinking water. Uranium in the samples was measured by a laser fluorimetry technique. According to results, the concentration values found in the wells ranged from 1.0 to 10.90 μgL -1 , while nearly 95 percent of the cities had uranium concentrations in the wells at less than 4.70 μgL -1 . Surface waters showed uranium concentrations in the range of 0.75 to 2.58 μgL -1 . The daily intake of uranium from drinking water was estimated to range from 2.04 to 21.80 μgd -1 , with the mean value of 5.44 μgd -1 . Conclusion: Highest uranium mean concentration of 10.9 μgL -1 was found in Ardabil area where more studies should be done in that province in the future

Airborne uranium, its concentration and toxicity in uranium enrichment facilities

International Nuclear Information System (INIS)

Thomas, J.; Mauro, J.; Ryniker, J.; Fellman, R.

1979-02-01

The release of uranium hexafluoride and its hydrolysis products into the work environment of a plant for enriching uranium by means of gas centrifuges is discussed. The maximum permissible mass and curie concentration of airborne uranium (U) is identified as a function of the enrichment level (i.e., U-235/total U), and chemical and physical form. A discussion of the chemical and radiological toxicity of uranium as a function of enrichment and chemical form is included. The toxicity of products of UF 6 hydrolysis in the atmosphere, namely, UO 2 F 2 and HF, the particle size of toxic particulate material produced from this hydrolysis, and the toxic effects of HF and other potential fluoride compounds are also discussed. Results of an investigation of known effects of humidity and temperature on particle size of UO 2 F 2 produced by the reaction of UF 6 with water vapor in the air are reported. The relationship of the solubility of uranium compounds to their toxic effects was studied. Identification and discussion of the standards potentially applicable to airborne uranium compounds in the working environment are presented. The effectiveness of High Efficiency Particulate (HEPA) filters subjected to the corrosive environment imposed by the presence of hydrogen fluoride is discussed

The conditions for uranium concentration in the phosphates of Tchivoula, Congo

International Nuclear Information System (INIS)

Giresse, P.; N'Landou, J. de Dieu; Wiber, M.

1986-01-01

The processes of deposition of marine phosphates in the Maastrichtian seas of the Congo do not appear capable alone of having produced the significant concentrations of uranium found. Diagenetic phenomena resulted in a mobilisation and a secondary concentration of uranium in the interior of recrystallized apatites. This secondary uranium may have been derived from the residual organic matrix in the deposit. Towards the top of the beds, hydrolysis of the apatites and authigenesis of crandallite, barrandite and ferruginous variscite led to uranium concentrations which are characteristic of alteration in a tropical climate. In contrast, wavellite, the final product of supergene alteration does not retain uranium. In the case of the Tchivoula deposits, the overlying Paleocene beds may have been the source of the uraniferous solutions' downslope movement which favored concentration in the underlying sediments. (orig.)

Effect of ion concentrations on uranium absorption from sodium carbonate solutions

International Nuclear Information System (INIS)

Traut, D.E.; El Hazek, N.M.T.; Palmer, G.R.; Nichols, I.L.

1979-01-01

The effect of various ion concentrations on uranium absorption from a sodium carbonate solution by a strong-base, anion resin was investigated in order to help assure an adequate uranium supply for future needs. The studies were conducted to improve the recovery of uranium from in situ leach solutions by ion exchange. The effects of carbonate, bicarbonate, chloride, and sulfate ions were examined. Relatively low (less than 5 g/l) concentrations of chloride, sulfate, and bicarbonate were found to be detrimental to the absorption of uranium. High (greater than 10 g/l) carbonate concentrations also adversely affected the uranium absorption. In addition, the effect of initial resin form was investigated in tests of the chloride, carbonate, and bicarbonate forms; resin form was shown to have no effect on the absorption of uranium

Development of system on predicting uranium concentration from pregnant solution

International Nuclear Information System (INIS)

Yi Weiping

2004-01-01

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

Analytical procedure for the titrimetric determination of uranium in concentrates

International Nuclear Information System (INIS)

Florence, T.M.; Pakalns, P.

1989-01-01

In 1964 Davis and gray published a titrimetric method for uranium which does not require column reductors, electronic instruments or inert atmospheres, and is sufficiently selective to enable uranium to be determined without prior separation. The method involves reduction of uranium (VI) to (IV) by ferrous sulphate in concentrated phosphoric acid medium. The excess ion (II) is then selectively oxidised by nitric acid using molybdenum catalyst. After addition of sulphuric acid and dilution with water, the uranium (IV) is titrated with standard potassium dichromate, using barium diphenylamine sulphonate indicator. This method has been found to be simple, precise and reliable, and applicable to a wide range of uranium-containing materials. The method given here for determining uranium in concentrates is essentially that of Davies and Gray. Its applications, apparatus, reagents, procedures and accuracy and precision are discussed. 10 refs

Fabrication procedures for manufacturing high uranium concentration dispersion fuel elements

International Nuclear Information System (INIS)

Souza, J.A.B.; Durazzo, M.

2010-01-01

IPEN developed and made available for routine production the technology for manufacturing dispersion type fuel elements for use in research reactors. However, the fuel produced at IPEN is limited to the uranium concentration of 3.0 gU/cm 3 by using the U 3 Si 2 -Al dispersion. Increasing the uranium concentration of the fuel is interesting by the possibility of increasing the reactor core reactivity and lifetime of the fuel. It is possible to increase the concentration of uranium in the fuel up to the technological limit of 4.8 gU/cm 3 for the U 3 Si 2 -Al dispersion, which is well placed around the world. This new fuel will be applicable in the new Brazilian-Multipurpose Reactor RMB. This study aimed to develop the manufacturing process of high uranium concentration fuel, redefining the procedures currently used in the manufacture of IPEN. This paper describes the main procedures adjustments that will be necessary. (author)

Fabrication procedures for manufacturing high uranium concentration dispersion fuel elements

Energy Technology Data Exchange (ETDEWEB)

Souza, Jose Antonio Batista de; Durazzo, Michelangelo, E-mail: jasouza@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2011-07-01

IPEN developed and made available for routine production the technology for manufacturing dispersion type fuel elements for use in research reactors. However, the fuel produced at IPEN is limited to the uranium concentration of 3.0 g U/c m3 by using the U{sub 3}Si{sub 2}-Al dispersion. Increasing the uranium concentration of the fuel is interesting by the possibility of increasing the reactor core reactivity and lifetime of the fuel. It is possible to increase the concentration of uranium in the fuel up to the technological limit of 4.8 g U/c m3 for the U{sub 3}Si{sub 2}-Al dispersion, which is well placed around the world. This new fuel will be applicable in the new Brazilian- Multipurpose Reactor RMB. This study aimed to develop the manufacturing process of high uranium concentration fuel, redefining the procedures currently used in the manufacture of IPEN. This paper describes the main procedures adjustments that will be necessary. (author)

Automated assay of uranium solution concentration and enrichment

International Nuclear Information System (INIS)

Horley, E.C.; Gainer, K.; Hansen, W.J.; Kelley, T.A.; Parker, J.L.; Sampson, T.E.; Walton, G.; Jones, S.A.

1992-01-01

For the first time, the concentration and enrichment of uranium solutions can be measured in one step. We have developed a new instrument to automatically measure the concentration and enrichment of uranium solutions through the adaptation of a commercial robot. Two identical solution enrichment systems are being installed in the Portsmouth Gaseous Diffusion Plant. These automated systems will reduce radiation exposure to personnel and increase the reliability and repeatability of the measurements. Each robotic system can process up to 40 batch and 8 priority samples in an unattended mode. Both passive gamma-ray and x-ray fluorescence (XRF) analyses are performed to determine total uranium concentration and 235 U enrichment. Coded samples are read by a bar-code reader to determine measurement requirements, then assayed by either or both of the gamma-ray and XRF instruments. The robot moves the sample containers and operates all shield doors and shutters, reducing hardware complexity. If the robots is out of service, an operator can manually perform all operations

Uranium mining and production of concentrates in India

International Nuclear Information System (INIS)

Bhasin, J.L.

1997-01-01

In order to meet the uranium requirements for the atomic power programme of the country, uranium deposits were explored, mined and concentrates were produced indigenously. The geology of the areas, mode of entries and the various extraction methods deployed in different mines with their constraints are described. The various equipments used in mining and processing activities are elaborated. The flow sheets for processing the uranium ore and that of the effluent treatment plant are given in detail. The future plans of the company for undertaking the new projects to meet the demand of uranium requirement for the increasing nuclear power programme are given. (author). 18 figs

Effect of pH and uranium concentration on interaction of uranium(VI) and uranium(IV) with organic ligands in aqueous solutions

International Nuclear Information System (INIS)

Li, W.C.; Victor, D.M.; Chakrabarti, C.L.

1980-01-01

The effect of pH and uranium concentration on the interactions of uranium(VI) and uranium(IV) with organic ligands was studied by employing dialysis and ultrafiltration techniques. The interactions of U(VI) and U(IV) with organic ligands in nitrate or chloride aqueous solution have been found to be pH-dependent. The stability constants of uranium-organic complexes decrease in the order: fulvic acid>humic acid>tannic acid for U(VI) and humic acid>tannic acid>fulvic acid for U(IV). Scatchard plots for the uranium-organic acid systems indicate two types of binding sites with a difference in stability constants of about 10 2 . Ultrafiltration of uranium-humic acid complexes indicates that U(VI) and U(IV) ions are concentrated in larger molecular size fractions (>5.1 nm) at pH less than or equal to 3 and in smaller molecular size fractions (in the range 5.1 to 3.1 nm and 2.4 to 1.9 nm) at pH greater than or equal to 5. 7 figures, 4 tables

Uranium recovery from phosphate rocks concentrated

International Nuclear Information System (INIS)

Azevedo, M.F. de.

1986-01-01

The reserves, geological data, chemical data and technical flowsheet from COPEBRAS and Goiasfertil ores are described, including the process of mining ore concentration. Samples of Goiasfertil ores are analysed by gravimetric analysis, for phosphate, and spectrofluorimetry for uranium. (author)

Uranium concentrations in human bone

International Nuclear Information System (INIS)

Schlenker, R.A.; Oltman, B.G.

1981-01-01

The uranium concentration in bone from an individual injected with 239 Pu has been determined, using the fission-track method. The data are consistent with those reported about 10 years ago by Welford and Baird for New York City area residents and by Hamilton in England. They are at variance with the more recent data of Welford et al

Determination of uranium concentration in an ore sample using laser-induced breakdown spectroscopy

International Nuclear Information System (INIS)

Kim, Y.-S.; Han, B.-Y.; Shin, H.S.; Kim, H.D.; Jung, E.C.; Jung, J.H.; Na, S.H.

2012-01-01

Laser-induced breakdown spectroscopy (LIBS) has been recognized as a promising technique for analyzing sensitive nuclear materials such as uranium, plutonium, and curium in a high-radiation environment, especially since the implementation of IAEA (International Atomic Energy Agency) safeguards. The uranium spectra of ore samples were quantitatively analyzed prior to analyzing sensitive materials in the nuclear industry. The purpose of this experiment is to extract quantitative information about the uranium in a uranium ore using a standard addition approach. The uranium ore samples containing different concentrations of U were prepared by mixing raw ore powder with natural uranium oxide powders. Calibration sets of 0.2, 0.4, 0.6, 0.8 and 1.0 wt.% uranium concentrations within the uranium ore sample were achieved. A pulsed and Q-switched Nd:YAG laser at a wavelength of 532 nm was used as a light source. An echelle spectrometer that covers a 190–420 nm wavelength range is used to generate a calibration curve and determine the detection limit of uranium in the ore matrix. The neutral atomic-emission peak at a wavelength of 356.659 nm indicated a detection limit of ∼ 158 ppm for uranium, and the uranium concentration was determined in a raw ore sample that has an unknown quantity of uranium. - Highlights: ► The feasibility of LIBS application to monitor uranium element was carried out. ► The detection limit of U in ore was determined by a standard additional approach. ► Quantitative analyses of U concentration in a natural uranium ore were performed.

Study of Uranium Concentrations in Water and Organic Material from Streams in Sweden

International Nuclear Information System (INIS)

Ek, J.

1981-12-01

The purpose of the investigation has been to study how uranium concentrations in stream water and organic material are related to various geological parameters such as rock types, average uranium content and radioactivity, fracturing, leachability of uranium from the bedrock, occurrence of uranium mineralisations and thickness and type of Quarternary deposits. The investigation has also taken account of the effects of environmental factors such as climate , precipitation, height above sea level and topography. The background concentration of uranium in organic stream sediment varies from 1 ppm to 45 ppm, with a background value of 10 ppm for all 14 areas considered together. The threshold value for organic stream material varies from 3 ppm U to 303 ppm U with a threshold value of 133 ppm U for all 14 areas considered together. For water, the background concentration varies between the 5 areas from 0.2 ppb U to 0.7 ppb U with a background value of 0.4 ppb U for all 5 areas together. The threshold value varies from 0.3 ppb U to 5.2 ppb U with a threshold value of 2.9 ppb U for all 5 areas together. An investigation of the correlation between uranium concentrations in water and organic stream material from one and the same sampling point shows a positive correlation for high concentrations, but the correlation becomes successively less significant with lower concentrations. Uranium concentrations in organic stream material and water are positively correlated with the following geological parameters:1) Background concentrations of uranium in the bedrock. 2) Abundance of fractures in the bedrock. 3) Leachability of uranium from the bedrock. 4) Presence of uranium mineralisations. For organic stream material, this positive correlation is obtained for both high and low uranium concentrations whereas for water it occurs only with high concentrations. In areas of broken topography and high relief, there is a more clearly defined correlation to the bedrock than in areas of

Uranium concentrations in the water consumed by the resident population in the vicinity of the Lagoa Real uranium province, Bahia, Brazil

Energy Technology Data Exchange (ETDEWEB)

Silva, Luciana S. [State University of Bahia (UNEB), Campus Caetite, BA (Brazil); Pecequilo, Brigitte R.S.; Sarkis, Jorge; Nisti, Marcelo B., E-mail: brigitte@ipen.br, E-mail: jesarkis@ipen.br, E-mail: mbnisti@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2011-07-01

The Lagoa Real Uranium Province, situated in South Central Bahia in the region of Caetite and Lagoa Real, is considered the most important monomineralic province of Brazil. The urban population who lives in the proximities of this uranium province in the cities of Caetite, Lagoa Real and Livramento uses public supply water, while the inhabitants of the rural area due to long terms of dry weather use water from wells, cisterns, small dams, reservoirs and dikes which are supplied with the rains. In this work it was determined the concentration of uranium in the water consumed by the rural and urban population living in the proximities of the Lagoa Real Uranium Province. The study comprehends 32 sampling spots spread throughout the region of interest. Samples were collected in January and July 2010, covering superficial, underground and public supply water from the region. The uranium concentrations were determined by an inductively coupled plasma mass spectrometer (ICP-MS). Preliminary results showed that the uranium concentrations in the water from the Lagoa Real Uranium Province varied from 0.064 {+-} 0.005 {mu}g.L{sup -1} to 90 {+-} 1,5 {+-}g.L{sup -1}. It was observed that only two of them obtained values higher than the World Health Organization's recommended limit (2011) of 30 {mu}g.L{sup -1} for maximum uranium concentration in the water for human consumption. For a conclusive evaluation, the uranium concentrations results will be analyzed together with total alpha and beta concentrations determined elsewhere for the same samples. (author)

Uranium concentrations in the water consumed by the resident population in the vicinity of the Lagoa Real uranium province, Bahia, Brazil

International Nuclear Information System (INIS)

Silva, Luciana S.; Pecequilo, Brigitte R.S.; Sarkis, Jorge; Nisti, Marcelo B.

2011-01-01

The Lagoa Real Uranium Province, situated in South Central Bahia in the region of Caetite and Lagoa Real, is considered the most important monomineralic province of Brazil. The urban population who lives in the proximities of this uranium province in the cities of Caetite, Lagoa Real and Livramento uses public supply water, while the inhabitants of the rural area due to long terms of dry weather use water from wells, cisterns, small dams, reservoirs and dikes which are supplied with the rains. In this work it was determined the concentration of uranium in the water consumed by the rural and urban population living in the proximities of the Lagoa Real Uranium Province. The study comprehends 32 sampling spots spread throughout the region of interest. Samples were collected in January and July 2010, covering superficial, underground and public supply water from the region. The uranium concentrations were determined by an inductively coupled plasma mass spectrometer (ICP-MS). Preliminary results showed that the uranium concentrations in the water from the Lagoa Real Uranium Province varied from 0.064 ± 0.005 μg.L -1 to 90 ± 1,5 ±g.L -1 . It was observed that only two of them obtained values higher than the World Health Organization's recommended limit (2011) of 30 μg.L -1 for maximum uranium concentration in the water for human consumption. For a conclusive evaluation, the uranium concentrations results will be analyzed together with total alpha and beta concentrations determined elsewhere for the same samples. (author)

Management of wastes from the refining and conversion of uranium ore concentrate to uranium hexafluoride

International Nuclear Information System (INIS)

1981-01-01

This report is the outcome of an IAEA Advisory Group Meeting on ''Waste Management Aspects in Relation to the Refining of Uranium Ore Concentrates and their Conversion to Uranium Hexafluoride'', which was held in Vienna from 17 to 21 December 1979. The report summarizes the main topics discussed at the meeting and gives an overview of uranium refining processes, being used in nuclear industry. The meeting was organized by the International Atomic Energy Agency, Radioactive Waste Management Section

Uranium concentrations in sediments of the Suez Canal

International Nuclear Information System (INIS)

Ibrahiem, N.M.; Pimpl, M.

1994-01-01

Suez Canal bottom sediment samples have been analyzed by alpha-spectrometry for the measurement of uranium. This method is based on the extraction of uranium with trioctylphosphine oxide/cyclohexane (TOPO) followed by reextraction and separation on anion exchange resins, and finally electrodeposition. The α-activity of 238 U and 234 U were measured by surface barrier detectors, in Bq/kg dry weight. The obtained results were compared with concentrations determined by γ measurements. The results point to a state of disequilibrium between 238 U and RaeU (radium equivalent uranium) which is attributed to the escape of radon. (author)

Recovery of uranium mineral from Liaoning Fengcheng ludwigite ore by gravity concentration

International Nuclear Information System (INIS)

Zhang Tao; Liang Haijun; Xue Xiangxin

2009-01-01

A laboratory research was carried out to recover uranium mineral from Liaoning Fengcheng ludwigite ore. Gravity concentration methods including hydroclone, spiral chute and shaking table were applied in this study. The results show that a concentrate with uranium grade of 0.216% and recovery of 44.24% could be produced from the feed of uranium content 0.006 3%. This research is helpful to comprehensive utilization of the mineral resources. Increasing further uranium mineral liberation degree is the key to improve separation effects. (authors)

Modeled atmospheric radon concentrations from uranium mines

Energy Technology Data Exchange (ETDEWEB)

Droppo, J.G.

1985-04-01

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

Modeled atmospheric radon concentrations from uranium mines

International Nuclear Information System (INIS)

Droppo, J.G.

1985-04-01

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

Concentration factors of uranium mineralization in VII depositional cycle of Shuixigou group, lower-middle Jurassic at Wukurqi uranium deposit, Yili basin

International Nuclear Information System (INIS)

Liu Taoyong

2004-01-01

Starting with the analysis on uranium mineralization, this paper emphatically discusses factors related to uranium concentration in VII depositional cycle, such as the structure, the paleoclimate, the lithofacies-paleogeography, the lithology, the hydrogeology, the geochemistry, and the content of effective reductant. The author suggests that key factors of uranium migration and concentration at Wukurqi uranium deposit are the existence of ore-hosting formation (sand body), the long-term recharge of oxygen and uranium-bearing groundwater, the existence of effective reductant in ore-hosting formation

Physicochemical characterization of Capstone depleted uranium aerosols I: uranium concentration in aerosols as a function of time and particle size.

Science.gov (United States)

Parkhurst, Mary Ann; Cheng, Yung Sung; Kenoyer, Judson L; Traub, Richard J

2009-03-01

During the Capstone Depleted Uranium (DU) Aerosol Study, aerosols containing DU were produced inside unventilated armored vehicles (i.e., Abrams tanks and Bradley Fighting Vehicles) by perforation with large-caliber DU penetrators. These aerosols were collected and characterized, and the data were subsequently used to assess human health risks to personnel exposed to DU aerosols. The DU content of each aerosol sample was first quantified by radioanalytical methods, and selected samples, primarily those from the cyclone separator grit chambers, were analyzed radiochemically. Deposition occurred inside the vehicles as particles settled on interior surfaces. Settling rates of uranium from the aerosols were evaluated using filter cassette samples that collected aerosol as total mass over eight sequential time intervals. A moving filter was used to collect aerosol samples over time, particularly within the first minute after a shot. The results demonstrate that the peak uranium concentration in the aerosol occurred in the first 10 s after perforation, and the concentration decreased in the Abrams tank shots to about 50% within 1 min and to less than 2% after 30 min. The initial and maximum uranium concentrations were lower in the Bradley vehicle than those observed in the Abrams tank, and the concentration levels decreased more slowly. Uranium mass concentrations in the aerosols as a function of particle size were evaluated using samples collected in a cyclone sampler, which collected aerosol continuously for 2 h after perforation. The percentages of uranium mass in the cyclone separator stages ranged from 38 to 72% for the Abrams tank with conventional armor. In most cases, it varied with particle size, typically with less uranium associated with the smaller particle sizes. Neither the Abrams tank with DU armor nor the Bradley vehicle results were specifically correlated with particle size and can best be represented by their average uranium mass concentrations of 65

Determination of uranium metal concentration in irradiated fuel storage basin sludge using selective dissolution

International Nuclear Information System (INIS)

Delegard, C.H.; Sinkov, S.I.; Chenault, J.W.; Schmidt, A.J.; Pool, K.N.; Welsh, T.L.

2014-01-01

Irradiated uranium metal fuel was stored underwater in the K East and K West storage basins at the US Department of Energy Hanford Site. The uranium metal under damaged cladding reacted with water to generate hydrogen gas, uranium oxides, and spalled uranium metal particles which intermingled with other particulates to form sludge. While the fuel has been removed, uranium metal in the sludge remains hazardous. An expeditious routine method to analyze 0.03 wt% uranium metal in the presence of >30 wt% total uranium was needed to support safe sludge management and processing. A selective dissolution method was designed based on the rapid uranium oxide dissolution but very low uranium metal corrosion rates in hot concentrated phosphoric acid. The uranium metal-bearing heel from the phosphoric acid step then is rinsed before the uranium metal is dissolved in hot concentrated nitric acid for analysis. Technical underpinnings of the selective dissolution method, including the influence of sludge components, were investigated to design the steps and define the reagents, quantities, concentrations, temperatures, and times within the selective dissolution analysis. Tests with simulant sludge proved the technique feasible. Tests with genuine sludge showed a 0.0028 ± 0.0037 wt% (at one standard deviation) uranium metal analytical background, a 0.011 wt% detection limit, and a 0.030 wt% quantitation limit in settled (wet) sludge. In tests using genuine K Basin sludge spiked with uranium metal at concentrations above the 0.030 wt% ± 25 % (relative) quantitation limit, uranium metal recoveries averaged 99.5 % with a relative standard deviation of 3.5 %. (author)

Concentration of uranium in seawater by flotation

International Nuclear Information System (INIS)

Nozaki, Toru; Yamashita, Hiroshi

1986-01-01

A method has been developed for the concentration of uranium in seawater by precipitation flotation-carbonate extraction-ion flotation. Uranium in seawater was coprecipitated with hydrated iron (III) oxide by adjusting the pH to 5.5 after addition of 1.0 x 10 -3 mol/l of iron (III) and agitating for 1 hr, and the precipitate was floated with 1.0 x 10 -5 mol/l of sodium oleate and 5.0 x 10 -5 mol/l of sodium lauryl sulfate by bubbling nitrogen through the seawater for 15 min. Uranium was extracted from the precipitate scum at the yield of 89 % with 100 ml of 1.8 % of ammonium carbonate solution by agitating for 2 hr, and floated with 1.2 x 10 -3 mol/l of cetylpyridinium chloride by bubbling nitrogen through the extract diluted 5-fold for 30 min in the recovery of about 100 %. The fairly selective recovery of uranium was obtained from 4 l of seawater at the yield of 87 % throughout the entire process. (author)

Determination of trace concentration of uranium in soils by the nuclear track technique

International Nuclear Information System (INIS)

Islam, G.S.; Abdullah, M.N.A.

1998-04-01

Solid state nuclear track detector CR-39 has been used to estimate trace concentration of uranium in soil and sand samples from various places of Bangladesh. Uranium contents in soil samples have been found to vary from ∼3.79 to ∼8.63 ppm and in sand samples from ∼2.39 to ∼6.53 ppm. The mean concentration in soil and in sand samples were found to be ∼4.52 and ∼2.96 ppm respectively. The maximum uranium concentration in soil samples was observed in Sylhet while the uranium concentration of sand was found to be maximum in the sea beach of Cox's Bazar. The implication of results is briefly discussed in the paper. (author)

Paleozoic unconformities favorable for uranium concentration in northern Appalachian basin

International Nuclear Information System (INIS)

Dennison, J.M.

1986-01-01

Unconformities can redistribute uranium from protore rock as ground water moves through poorly consolidated strata beneath the erosion surface, or later moves along the unconformity. Groundwater could migrate farther than in present-day lithified Paleozoic strata in the Appalachian basin, now locally deformed by the Taconic and Allegheny orogenies. Several paleoaquifer systems could have developed uranium geochemical cells. Sandstone mineralogy, occurrences of fluvial strata, and reduzate facies are important factors. Other possibilities include silcrete developed during desert exposure, and uranium concentrated in paleokarst. Thirteen unconformities are evaluated to determine favorable areas for uranium concentration. Cambrian Potsdam sandstone (New York) contains arkoses and possible silcretes just above crystalline basement. Unconformities involving beveled sandstones and possible fluvial strata include Cambrian Hardyston sandstone (New Jersey), Cambrian Potsdam Sandstone (New York), Ordovician Oswego and Juniata formations (Pennsylvania and New York), Silurian Medina Group (New York), and Silurian Vernon, High Falls, and Longwood formations (New York and New Jersey). Devonian Catskill Formation is beveled by Pennsylvanian strata (New York and Pennsylvania). The pre-Pennsylvanian unconformity also bevels Lower Mississippian Pocono, Knapp, and Waverly strata (Pennsylvania, New York, and Ohio), truncates Upper Mississippian Mauch Chunk Formation (Pennsylvania), and forms paleokarst on Mississippian Loyalhanna Limestone (Pennsylvania) and Maxville Limestone (Ohio). Strata associated with these unconformities contain several reports of uranium. Unconformities unfavorable for uranium concentration occur beneath the Middle Ordovician (New York), Middle Devonian (Ohio and New York), and Upper Devonian (Ohio and New York); these involve marine strata overlying marine strata and probably much submarine erosion

Measurements of natural uranium concentration in Caspian Sea and Persian Gulf water by laser fluorimetric method

International Nuclear Information System (INIS)

Garshasbi, H.; Karimi Diba, J.; Jahanbakhshian, M. H.; Asghari, S. K.; Heravi, G. H.

2005-01-01

Natural uranium exists in earth crust and seawater. The concentration of uranium might increase by human manipulation or geological changes. The aim of this study was to verify susceptibility of laser fluorimetry method to determine the uranium concentration in Caspian Sea and Persian Gulf water. Materials and Methods: Laser fluorimetric method was used to determine the uranium concentration in several samples prepared from Caspian Sea and Persian Gulf water. Biological and chemical substances were eliminated in samples for better evaluation of the method. Results: As the concentration of natural uranium in samples increases, the response of instrument (uranium analyzer) increases accordingly. The standard deviation also increased slightly and gradually. Conclusion: Results indicate that the laser fluorimetry method show a reliable and accurate response with uranium concentration up to 100 μg/L in samples after removal of biological and organic substances

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

International Nuclear Information System (INIS)

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

2007-01-01

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

On the peculiarities of subsurface uranium concentrations in the arid regions

International Nuclear Information System (INIS)

Kochenov, A.V.; Chernikov, A.A.

1976-01-01

The general features of uranium distribution in the zone of hypergenesis of the area under investigation suggest a lack of accumulations due to climatic or landscape factors alone and formed at the expense of background near-clark contents of uranium in primary rocks. The low uranium concentrations in the debris layer of weathered crusts of acidic effusive rocks and granites as well as in salt marshes are of areal distribution and, in practice, never recorded as anomalies. The processes of salt formation in the area discussed appear, in the absence of organic matter in the sediments, to be insufficient by themselves for the accumulation of uranium from its near-clark contents in the primary rocks. At the same time the arid conditions are undoubtedly favorable for the formation and persistence of accumulative diffusion aureoles emphasizing and revealing on the surface the smallest and poorest primary concentrations of uranium. It is inadmissible to extrapolate the results of a study of one area to the entire variety of geomorphological conditions of the arid zone. The data reported show that care should be taken in interpreting uranium anomalies in arid areas, by all means taking account of the geological structure of the particular anomalous area and the uranium resources of the primary rocks

Organic matter in uranium concentration during ancient bed oxidation of carboniferons sediments

International Nuclear Information System (INIS)

Kruglova, V.G.; Uspenskij, V.A.; Dement'ev, P.K.; Kochenov, A.V.

1984-01-01

Changes in the organic matter accompanying the process of epigenetic ore formation are studied using the example of a deposit localized in carboniferous molasse strata of the Cretaceous period. Peculiarities of the organic matter as the main mineralization agent are studied by a complex of physical and themical methods. A distinct relationship between the uranium concentration and the degree of organic matter oxigenation is a most characteristic feature of the ore localization, however, there is no direct correlation between the contents of uranium and organic matter in ores. Uranium minerallzation was accumulated during infiltration of acid uraniferous.waters into grey stratum in the process of the bed oxidation zone formation oxidizing. Brown coal matter possessing a maximum adsorbability, as compared to other sedimentary rocks, apprared to be the uranium precipitator. The adsorption was accompanie by the formation of proper uranium minerals (coffinite, pitchblende) due to uranium reduction by oxidizing organic matter. Thus, the oxidative epigenesis was an are-forming process with the uranium concentration on organic matter proportionally to oxidation of the latter

Concentrations of heavy metals (lead, manganese, cadmium) in blood and urine of former uranium workers

International Nuclear Information System (INIS)

Apostolova, D.; Pavlova, S.; Paskalev, Z.

1999-01-01

Uranium ores contain heavy metals and other stable chemical elements as oxides, hydro-carbonates, sulphates, etc. During chemical processing of ore they could be transformed into compounds soluble in biologic liquids. The purpose of this study was to determine the combined intoxication of uranium miners and millers by heavy metals and radiation. Heavy metal (lead, manganese and cadmium) concentrations in blood and urine od 149 former uranium miners and millers were determined by AAS method. Data of significantly increased lead and manganese concentration in blood (p<0.05) of two groups were established in comparison with a control group. There is no statistical significant differences in the cadmium concentrations. The lead and manganese blood levels at the uranium millers were significant higher than those of the uranium miner group (p<0.05). Tendency towards increased blood lead concentrations of uranium millers depending on the length of service was established

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

Science.gov (United States)

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

2007-01-01

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

Uranium hydrogeochemical and stream sediment reconnaissance of the Newcastle NTMS Quadrangle, Wyoming, including concentrations of forty-two additional elements

International Nuclear Information System (INIS)

Goff, S.J.; Sandoval, W.F.; Gallimore, D.L.; Talcott, C.L.; Martinez, R.G.; Minor, M.E.; Mills, C.F.

1980-06-01

Water and sediment samples were collected and each water sample was analyzed for U, and each sediment sample was analyzed for 43 elements, including U and Th. Uranium concentrations in water samples range from below the detection limit of 0.02 ppB to 702.26 ppB and have a median of 1.73 ppB and a mean of 11.76 ppB. Water samples containing high uranium concentrations generally are associated with known uranium mining activity or units known to be uranium bearing. About one-third of the water samples containing high uranium concentrations were collected from locations within the Pumpkin Buttes and Turnercrest-Ross Districts. Nearly half of the water samples containing high uranium concentrations were collected from locations just west of the Monument Hill and Highland Flats-Box Creek Districts. Similar anomalous uranium concentrations in this region have been reported updip from Exxon's Highland uranium deposits. High uranium concentrations were also found associated with the Lance Creek-Old Woman Anticline District. Uranium concentrations in sediment samples range from 1.14 to 220.70 ppM and have a median of 3.37 ppM and a mean of 4.03 ppM. Throughout the major uranium mining districts of the Powder River Basin, sediment samples with high uranium concentrations were collected from dry streams located near wells producing water samples with high uranium concentrations. High uranium concentrations were also found associated with the Lance Creek oil field where uranium mineralization is known in the White River formation. High uranium concentrations were also found in sediment samples in areas where uranium mineralization is not known. These samples are from dry streams in areas underlain by the White River formation, the Niobrara formation, and the Pierre, Carlisle, Belle Fourche, and Mowry shales

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

Science.gov (United States)

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

2007-01-01

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

Recovery of uranium in the production of concentrated phosphoric acid by a hemihydrate process

International Nuclear Information System (INIS)

Nakajima, S.; Miyamoto, M.

1983-01-01

Nissan Chemical Industries as manufacturers of phosphoric acid have studied the recovery of uranium, based on a concentrated phosphoric acid production process. The process consists of two stages, a hemihydrate stage with a formation of hemihydrate and a filtration section, followed by a dihydrate stage with hydration and a filtration section. In the hemihydrate stage, phosphate is treated with a mixture of phosphoric acid and sulphuric acid to produce phosphoric acid and hydrous calcium sulphate; the product is recovered in the filtration section and its concentration is 40-50% P 2 O 3 . In the dihydrate stage, the hemihydrate is transformed by re-dissolution and hydration, producing hydrous calcium sulphate, i.e. gypsum. This process therefore comprises two parts, each with different acid concentrations. As the extraction of uranium is easier in the case of a low concentration of phosphoric acid, the process consists of the recovery of uranium starting from the filtrate of the hydration section. The tests have shown that the yield of recovery of uranium was of the order of 80% disregarding the handling losses and no disadvantageous effect has been found in the combination of the process of uranium extraction with the process of concentrated phosphoric acid production. Compared with the classical process where uranium is recovered from acid with 30% P 2 O 5 , the process of producing high-concentration phosphoric acid such as the Nissan process, in which the uranium recovery is effected from acid with 15% P 2 O 5 from the hydration section, presents many advantages [fr

Fabrication procedures for manufacturing high uranium concentration dispersion fuel elements

International Nuclear Information System (INIS)

Souza, Jose Antonio Batista de

2011-01-01

IPEN-CNEN/SP developed the technology to produce the dispersion type fuel elements for research reactors and made it available for routine production. Today, the fuel produced in IPEN-CNEN/SP is limited to the uranium concentration of 3.0 gU/cm 3 for U 3 Si 2 -Al dispersion-based and 2.3 gU/cm 3 for U 3 O 8 -Al dispersion. The increase of uranium concentration in fuel plates enables the reactivity of the reactor core reactivity to be higher and extends the fuel life. Concerning technology, it is possible to increase the uranium concentration in the fuel meat up to the limit of 4.8 gU/cm 3 in U 3 Si 2 -Al dispersion and 3.2 gU/cm 3 U 3 O 8 -Al dispersion. These dispersions are well qualified worldwide. This work aims to develop the manufacturing process of both fuel meats with high uranium concentrations, by redefining the manufacturing procedures currently adopted in the Nuclear Fuel Center of IPEN-CNEN/SP. Based on the results, it was concluded that to achieve the desired concentration, it is necessary to make some changes in the established procedures, such as in the particle size of the fuel powder and in the feeding process inside the matrix, before briquette pressing. These studies have also shown that the fuel plates, with a high concentration of U 3 Si 2 -Al, met the used specifications. On the other hand, the appearance of the microstructure obtained from U 3 O 8 -Al dispersion fuel plates with 3.2 gU/cm 3 showed to be unsatisfactory, due to the considerably significant porosity observed. The developed fabrication procedure was applied to U 3 Si 2 production at 4.8 gU/cm 3 , with enriched uranium. The produced plates were used to assemble the fuel element IEA-228, which was irradiated in order to check its performance in the IEA-R1 reactor at IPEN-CNEN/SP. These new fuels have potential to be used in the new Brazilian Multipurpose Reactor - RMB. (author)

The effects of different uranium concentrations on soil microbial populations and enzymatic activities

International Nuclear Information System (INIS)

Bagherifam, S.; Lakziyan, A.; Ahmadi, S. J.; Fotovvat, A.; Rahimi, M. F.

2010-01-01

Uranium is an ubiquitous constituent of natural environment with an average concentration of 4 mg/kg in earth crust. However, in local areas it may exceed the normal concentration due to human activities resulting in radionuclide contamination in groundwater and surface soil. The effect of six levels of uranium concentration (0, 50, 100,250. 500 and 1000 mg kg -1 ) on soil phosphatase activities and microbial populations were studied in a completely randomized design as a factorial experiment with three replications. The results showed a significant decrease in phosphatase activity. The result of the experiment suggests that soil microbial populations (bacteria, funji and actinomycetes) decrease by increasing the uranium levels in the soil. Therefore, assessment of soil enzymatic activities and microbial populations can be helpful as a useful index for a better management of uranium and radioactive contaminated soils.

Comparative study of uranium concentration in water samples of SW and NE Punjab, India

International Nuclear Information System (INIS)

Saini, Komal; Bajwa, B.S.

2014-01-01

Since the commencement of the earth, radiations and natural radioactivity has always been a part of environment. Uranium is heaviest naturally occurring element which is widespread in nature, mainly occurs in granites mineral deposits. The natural weathering of rocks such as granite dissolves the natural uranium, which goes into groundwater by leaching and precipitation called illumination process. People are always exposed to certain amount of uranium from air, water, soil and food as it is usually present in these components. About 85% of ingested uranium enter into human body through drinking water which makes it very important to estimate uranium concentration in potable water. Uranium and some other heavy metals may increase the risk of kidney damage, cancer diseases where experimental evidence suggests that respiratory and reproductive system are also affected by uranium exposure. In the present study comparative study of uranium concentration in potable water samples of SW and NE Punjab has been analysed

Effects of uranium concentration on microbial community structure and functional potential.

Science.gov (United States)

Sutcliffe, Brodie; Chariton, Anthony A; Harford, Andrew J; Hose, Grant C; Greenfield, Paul; Elbourne, Liam D H; Oytam, Yalchin; Stephenson, Sarah; Midgley, David J; Paulsen, Ian T

2017-08-01

Located in the Northern Territory of Australia, Ranger uranium mine is directly adjacent to the UNESCO World Heritage listed Kakadu National Park, with rehabilitation targets needed to ensure the site can be incorporated into the park following the mine's closure in 2026. This study aimed to understand the impact of uranium concentration on microbial communities, in order to identify and describe potential breakpoints in microbial ecosystem services. This is the first study to report in situ deployment of uranium-spiked sediments along a concentration gradient (0-4000 mg U kg -1 ), with the study design maximising the advantages of both field surveys and laboratory manipulative studies. Changes to microbial communities were characterised through the use of amplicon and shotgun metagenomic next-generation sequencing. Significant changes to taxonomic and functional community assembly occurred at a concentration of 1500 mg U kg -1 sediment and above. At uranium concentrations of ≥ 1500 mg U kg -1 , genes associated with methanogenic consortia and processes increased in relative abundance, while numerous significant changes were also seen in the relative abundances of genes involved in nitrogen cycling. Such alterations in carbon and nitrogen cycling pathways suggest that taxonomic and functional changes to microbial communities may result in changes in ecosystem processes and resilience. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

Adaptive control theory of concentration in the uranium enrichment plant

International Nuclear Information System (INIS)

Sugitsue, Noritake; Miyagawa, Hiroshi; Yokoyama, Kaoru; Nakakura, Hiroyuki

1999-01-01

This paper presents the new adaptive control of concentration in the uranium enrichment plant. The purpose of this control system is average concentration control in production tram. As a result the accuracy and practical use of this control system have already been confirmed by the operation of the uranium enrichment demonstration plant. Three elements of technology are required to this method. The first is the measurement of the concentration using product flow quantity change. This technology shall be called 'Qp difference to Xp transform method'. The second is the relationship between temperature change and flow quantity using G.M.D.H. (Groupe Method of Data Handling) and the third is the estimation of temperature change using AR (Auto-regressive) model. (author)

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

Uranium concentration in building materials used in the central region of Egypt

International Nuclear Information System (INIS)

Higgy, R.H.; El-Tahawy, M.S.; Ghods, A.

1997-01-01

Within a radiological survey of the building materials used in the urban dwellings in the central region of Egypt, the uranium concentration in 80 representative samples of raw and fabricated building materials are determined using laser fluorimetry technique. For 40 samples from the studied raw building materials of sand, gravel, gypsum, lime-stone, granite and marble the determined uranium concentration values range between 0.3 and 3.6 ppm for all these samples except for one type of granite having the corresponding value of 7.8 ppm. For 37 samples from studied fabricated building materials of normal cement, clay brick, sand brick, tiles and ceramic plates the determined uranium concentration values range from 0.5 to 3.4 ppm. The corresponding values for three types of iron cement are 3.1, 6.1 and 9.3 ppm. The radium-226 content (of the uranium-238 series) in the same samples was determined using high resolution gamma-ray spectrometers based on HP Ge-detectors. The data obtained by the two techniques are in good agreement for the majority of the studied samples. (author)

Feasibility study of the dissolution rates of uranium ore dust, uranium concentrates and uranium compounds in simulated lung fluid

International Nuclear Information System (INIS)

Robertson, R.

1986-01-01

A flow-through apparatus has been devised to study the dissolution in simulated lung fluid of aerosol materials associated with the Canadian uranium industry. The apparatus has been experimentally applied over 16 day extraction periods to approximately 2g samples of < 38um and 53-75um particle-size fractions of both Elliot Lake and Mid-Western uranium ores. The extraction of uranium-238 was in the range 24-60% for these samples. The corresponding range for radium-226 was 8-26%. Thorium-230, lead-210, polonium-210, and thorium-232 were not significantly extracted. It was incidentally found that the elemental composition of the ores studied varies significantly with particle size, the radionuclide-containing minerals and several extractable stable elements being concentrated in the smaller size fraction. Samples of the refined compounds uranium dioxide and uranium trioxide were submitted to similar 16 day extraction experiments. Approximately 0.5% of the uranium was extracted from a 0.258g sample of unsintered (fluid bed) uranium dioxide of particle size < 38um. The corresponding figure for a 0.292g sample of uranium trioxide was 97%. Two aerosol samples on filters were also studied. Of the 88ug uranium initially measured on stage 2 of a cascade impactor sample collected from the yellow cake packing area of an Elliot Lake mill, essentially 100% was extracted over a 16 day period. The corresponding figure for an open face filter sample collected in a fuel fabrication plant and initially measured at 288ug uranium was approximately 3%. Recommendations are made with regard to further work of a research nature which would be useful in this area. Recommendations are also made on sampling methods, analytical methods and extraction conditions for various aerosols of interest which are to be studied in a work of broader scope designed to yield meaningful data in connection with lung dosimetry calculations

Process for recovering a uranium containing concentrate and purified phosphoric acid from a wet process phosphoric acid containing uranium

International Nuclear Information System (INIS)

Weterings, C.A.M.; Janssen, J.A.

1985-01-01

A process is claimed for recovering from a wet process phosphoric acid which contains uranium, a uranium containing concentrate and a purified phosphoric acid. The wet process phosphoric acid is treated with a precipitant in the presence of a reducing agent and an aliphatic ketone

Process for recovering a uranium containing concentrate and purified phosphoric acid from a wet process phosphoric acid containing uranium

Energy Technology Data Exchange (ETDEWEB)

Weterings, C.A.M.; Janssen, J.A.

1985-04-30

A process is claimed for recovering from a wet process phosphoric acid which contains uranium, a uranium containing concentrate and a purified phosphoric acid. The wet process phosphoric acid is treated with a precipitant in the presence of a reducing agent and an aliphatic ketone.

International uranium production. A South African perspective

International Nuclear Information System (INIS)

Sinclair-Smith, D.

1984-01-01

Between 1981 and 1983 South Africa experienced a decline in its uranium resources of 23% in the less than $80/kg U category and 12% in the less than $130/kg U category. In 1983 only $5 million was spent on exploration, with activities being concentrated in the Witwatersrand Basin as a byproduct of gold exploration. South Africa has maintained a production level of around 6000 mt U in 1981, 1982 and 1983. One unusual feature of the South African uranium scene is the ability to selectively dump relatively high grade uranium tailings after the extraction of gold and to rework this material as well as material dumped prior to the emergence of the uranium industry. Uranium from this source amounted to some 28% of total production in 1983. (L.L.) (2 tabs., 6 figs.)

Link between ore bodies and biosphere concentrations of uranium

International Nuclear Information System (INIS)

Gordon, S.

1992-01-01

A literature review of uranium exploration studies was carried out to determine the size and concentration of uranium anomalies in the biosphere. Fourteen sites were studied and uranium data were obtained for rocks, water-borne sediments, surface waters, groundwaters, soils and plants. Detailed descriptions of the study areas and of their uranium anomalies are provided. No statistical analyses of the data of anomaly sizes was undertaken because of the variation in the scale of the studies and in the threshold values used and the small number of samples for each medium. The threshold values and the size of the anomaly were found to be dependent on the scale of the study and of the sampling density. Sediments and surface waters were found to have the largest uranium dispersion. Although there was a wide range in the anomaly sizes it was possible to assign typical values for each medium. Based on a typical source of 1 km 2 in the rock it was found that anomalies of similar size as the source are expected in soils and plants, anomalies twice as large are typical for sediments and surface waters and anomalies of smaller areas than the source are possible for groundwater. Some limitations to providing typical groundwater anomaly sizes are outlined. Typical maximum concentrations for the sites studied were greater than 1300 ppm for rock, 10 to 110 ppm for sediment, and 5 ppb for surface waters. No typical values were observed for groundwater, soils and plants. Susceptibility of the host rock to leaching and the presence of discharge zones were assessed for their role in biosphere anomalies

Study PWA8 resin for chromatographic uranium concentration

International Nuclear Information System (INIS)

Coceancigh, Herman; Ramella, J. L.; Marrero, Julieta; Jiménez Rebagliati, Raúl

2013-01-01

For many years nuclear industry have been using resins as filler of chromatographic columns. These methods are specific and give reliable results in different applications, for those reasons are extremely useful as separation process. Currently the nuclear industry is growing and this brings new issues such as the need of reduction of the amount of waste, the optimization of the production process and others that the chromatography could solve with great results. AMBERLITETM PWA8 resin is an anion exchange resin which can be used for the removal of uranium from drinking water. In addition to high exchange capacity, this resin has excellent physical stability and a wide range of pH in which is operational. With the idea of concentrating uranium from wastes solution as main goal we made different experiments to understand the AMBERLITETM PWA8 and obtain the most important characteristics like; pH working range; capacity; activation and elution procedures. These procedures were developed and optimized the capacity was determined using a batch experiment and we obtain that the maximum capacity is 882,5 U ug /resin gr at a pH of 4,2. Following on from these results chromatographic experiments were performed in which both were obtained the percentage of recovery and the concentration factor. The percent recovery (% R) calculated as the percentage ratio between the total mass and the load mass eluted (% R = eluted mass / total mass * 100) was 94% with a concentration factor of 5 times From these results it is intended to concentrate wastes solutions from the fuel cycle processes with two main goals: decreasing volume for storage and for future reusing of the uranium coming from production. (author)

Effect of uranium concentrations on plant growth - a control study

International Nuclear Information System (INIS)

Verma, P.C.; Hegde, A.G.; Arey, N.C.

2010-01-01

This paper presents the details of pot culture experiments carried out to study the migration of uranium in soil to plant system. The effect of varying concentration and chemical forms of uranium on shoot and root length, shoot and root weight, leaf area, water potential, chlorophyll contents, soluble protein, total phenol etc. of two test crops were studied. In case of barley crop, the effect of uranium on seed yield and modulation were also studied. 100% germination could be achieved respectively after a period of 36 hours and 28 hours in uranyl acetate and uranyl nitrate in case of cowpea, whereas it is and 48 hours and 24 hours respectively for barley crop. Higher doses of uranium retarded both the speed as well as germination of seeds for tested crops

Uranium Concentration of Contaminated Zone due to the Cover Depth for Self-Disposal

International Nuclear Information System (INIS)

Koo, Dae Seo; Sung, Hyun Hee; Kim, Gye Nam; Kim, Seung Soo; Kim, Il Gook; Han, Gyu Seong; Choi, Jong Won

2016-01-01

To acquire radiation dose under self disposal from them, the study on decontamination of some uranium contaminated soil and concrete wastes was performed using electrokinetic-electrodialytic. In this study, we evaluated radiation dose due to cover depth on contaminated zone such as uranium contaminated soil and concrete wastes under radiation dose limit using RESRAD Version 6.5. At first, the calculation of the radiation dose on the contaminated zone are carried out. The second, the uranium concentration of contaminated zone due to the cover depth are also analyzed. The uranium contaminated soil and concrete wastes under radiation dose limit by decontaminating them have application to self-disposal of contaminated zone. The area of contaminated zone is 1,500 m"2. The thickness of contaminated zone is 2 m. The length parallel to aquifer flow is 43.702m. The age of the residents on contaminated zone is 15 years old. The period of evaluation on the contaminated zone is from regulation exemption of uranium contaminated soil and concrete wastes till 1,000 years. The calculation of the radiation dose on contaminated zone are carried out. The uranium concentration of contaminated zone due to the cover depth was also analyzed. as the cover depth increases, the uranium concentration has an increasing trend. As the cover depth increases, radiation dose of a person has a decreasing trend. As the cover depth increases, the radiation dose of residents has also a decreasing trend.

Uranium Concentration of Contaminated Zone due to the Cover Depth for Self-Disposal

Energy Technology Data Exchange (ETDEWEB)

Koo, Dae Seo; Sung, Hyun Hee; Kim, Gye Nam; Kim, Seung Soo; Kim, Il Gook; Han, Gyu Seong; Choi, Jong Won [KAERI, Daejeon (Korea, Republic of)

2016-05-15

To acquire radiation dose under self disposal from them, the study on decontamination of some uranium contaminated soil and concrete wastes was performed using electrokinetic-electrodialytic. In this study, we evaluated radiation dose due to cover depth on contaminated zone such as uranium contaminated soil and concrete wastes under radiation dose limit using RESRAD Version 6.5. At first, the calculation of the radiation dose on the contaminated zone are carried out. The second, the uranium concentration of contaminated zone due to the cover depth are also analyzed. The uranium contaminated soil and concrete wastes under radiation dose limit by decontaminating them have application to self-disposal of contaminated zone. The area of contaminated zone is 1,500 m{sup 2}. The thickness of contaminated zone is 2 m. The length parallel to aquifer flow is 43.702m. The age of the residents on contaminated zone is 15 years old. The period of evaluation on the contaminated zone is from regulation exemption of uranium contaminated soil and concrete wastes till 1,000 years. The calculation of the radiation dose on contaminated zone are carried out. The uranium concentration of contaminated zone due to the cover depth was also analyzed. as the cover depth increases, the uranium concentration has an increasing trend. As the cover depth increases, radiation dose of a person has a decreasing trend. As the cover depth increases, the radiation dose of residents has also a decreasing trend.

Uranium industry annual 1993

International Nuclear Information System (INIS)

1994-09-01

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

Uranium industry annual 1993

Energy Technology Data Exchange (ETDEWEB)

1994-09-01

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

Uranium concentration in blood samples of Southern Iraqi leukemia patients using CR-39 track detector

International Nuclear Information System (INIS)

Al-Hamzawi, A.A.; Al-Qadisiyah University, Qadisiyah; Jaafar, M.S.; Tawfiq, N.F.

2014-01-01

The simple and effective technique of fission track etch has been applied to determine trace concentration of uranium in human blood samples taken from two groups of male and female participants: leukemia patients and healthy subjects group. The blood samples of leukemia patients and healthy subjects were collected from three key southern governorates namely, Basrah, Muthanna and Dhi-Qar. These governorates were the centers of intensive military activities during the 1991 and 2003 Gulf wars, and the discarded weapons are still lying around in these regions. CR-39 track detector was used for registration of induced fission tracks. The results show that the highest recorded uranium concentration in the blood samples of leukemia patients was 4.71 ppb (female, 45 years old, from Basrah) and the minimum concentration was 1.91 ppb (male, 3 years old, from Muthanna). For healthy group, the maximum uranium concentration was 2.15 ppb (female, 55 years old, from Basrah) and the minimum concentration was 0.86 ppb (male, 5 years old, from Dhi-Qar). It has been found that the uranium concentrations in human blood samples of leukemia patients are higher than those of the healthy group. These uranium concentrations in the leukemia patients group were significantly different (P < 0.001) from those in the healthy group. (author)

Treatment technology of low concentration uranium-bearing wastewater and its research progress

International Nuclear Information System (INIS)

Wei Guangzhi; Xu Lechang

2007-01-01

With growth of the discharged uranium-bearing wastewater capacity, a low cost and effective treatment technology is required to avoid transferring and diffusion of the radioactive nuclides. On the basis of analyses of the source and characteristics of the low-concentration uranium-bearing wastewater, the conventional treatment technologies, such as, flocculating settling, ion exchange, concentration, adsorption, and some innovatory technologies, such as, membrane, microorganism, phytoremediation and zero-valent iron technology are introduced. (authors)

Optimization of dissolution process parameters for uranium ore concentrate powders

Energy Technology Data Exchange (ETDEWEB)

Misra, M.; Reddy, D.M.; Reddy, A.L.V.; Tiwari, S.K.; Venkataswamy, J.; Setty, D.S.; Sheela, S.; Saibaba, N. [Nuclear Fuel Complex, Hyderabad (India)

2013-07-01

Nuclear fuel complex processes Uranium Ore Concentrate (UOC) for producing uranium dioxide powder required for the fabrication of fuel assemblies for Pressurized Heavy Water Reactor (PHWR)s in India. UOC is dissolved in nitric acid and further purified by solvent extraction process for producing nuclear grade UO{sub 2} powder. Dissolution of UOC in nitric acid involves complex nitric oxide based reactions, since it is in the form of Uranium octa oxide (U{sub 3}O{sub 8}) or Uranium Dioxide (UO{sub 2}). The process kinetics of UOC dissolution is largely influenced by parameters like concentration and flow rate of nitric acid, temperature and air flow rate and found to have effect on recovery of nitric oxide as nitric acid. The plant scale dissolution of 2 MT batch in a single reactor is studied and observed excellent recovery of oxides of nitrogen (NO{sub x}) as nitric acid. The dissolution process is automated by PLC based Supervisory Control and Data Acquisition (SCADA) system for accurate control of process parameters and successfully dissolved around 200 Metric Tons of UOC. The paper covers complex chemistry involved in UOC dissolution process and also SCADA system. The solid and liquid reactions were studied along with multiple stoichiometry of nitrous oxide generated. (author)

Biological processes for concentrating trace elements from uranium mine waters. Technical completion report

International Nuclear Information System (INIS)

Brierley, C.L.; Brierley, J.A.

1981-12-01

Waste water from uranium mines in the Ambrosia Lake district near Grants, New Mexico, USA, contains uranium, selenium, radium and molybdenum. The Kerr-McGee Corporation has a novel treatment process for waters from two mines to reduce the concentrations of the trace contaminants. Particulates are settled by ponding, and the waters are passed through an ion exchange resin to remove uranium; barium chloride is added to precipitate sulfate and radium from the mine waters. The mine waters are subsequently passed through three consecutive algae ponds prior to discharge. Water, sediment and biological samples were collected over a 4-year period and analyzed to assess the role of biological agents in removal of inorganic trace contaminants from the mine waters. Some of the conclusions derived from this study are: (1) The concentrations of soluble uranium, selenium and molybdenum were not diminished in the mine waters by passage through the series of impoundments which constituted the mine water treatment facility. Uranium concentrations were reduced but this was due to passage of the water through an ion exchange column. (2) The particulate concentrations of the mine water were reduced at least ten-fold by passage of the waters through the impoundments. (3) The sediments were anoxic and enriched in uranium, molybdenum and selenium. The deposition of particulates and the formation of insoluble compounds were proposed as mechanisms for sediment enrichment. (4) The predominant algae of the treatment ponds were the filamentous Spirogyra and Oscillatoria, and the benthic alga, Chara. (5) Adsorptive processes resulted in the accumulation of metals in the algae cells. (6) Stimulation of sulfate reduction by the bacteria resulted in retention of molybdenum, selenium, and uranium in sediments. 1 figure, 16 tables

Monitoring of uranium concentrations in water samples collected near potentially hazardous objects in North-West Tajikistan.

Science.gov (United States)

Zoriy, P; Schläger, M; Murtazaev, K; Pillath, J; Zoriy, M; Heuel-Fabianek, B

2018-01-01

The water contamination near ecologically problematic objects was investigated between 2009 and 2014 in North-West Tajikistan as a part of a joint project between Forschungszentrum Jülich and Khujand State University. The main part of this work was the determination of uranium in water samples collected near the Degmay tailings dump, the Taboshar pit lake and the Syr Darya river. More than 130 water samples were collected and analyzed to monitor the uranium concentration near the investigated areas. Two different mass spectrometers and an ion chromatograph were used for element concentration measurements. Based on the results obtained, the uranium influence of the Degmay tailings on the rivers Khoja-Bakyrgan-Say and Syr Darya and surrounding water was not found. The uranium concentration in water samples was monitored for a lengthy period at seven locations Great differences in the uranium concentration in waters collected in 2010, 2011, 2012, 2013 for each location were not observed. Drinking water samples from the region of North-West Tajikistan were analyzed and compared with the World Health Organization's guidelines. Seven out of nine drinking water samples near Taboshar exceeded the WHO guideline value for uranium concentrations (30 μg/L). The average uranium concentration of water samples from Syr Darya for the period from 2009 to 2014 was determined to be 20.1 (±5.2) μg/L. The uranium contamination of the Syr Darya was determined from the western border to the eastern border and the results are shown in this paper. Copyright © 2017 Elsevier Ltd. All rights reserved.

Feasibility of Uranium Concentration Measurements for H Canyon Tank 16.7

International Nuclear Information System (INIS)

Lascola, R.J.

2003-01-01

Savannah River Technology Center (SRTC) evaluated the feasibility of using the H Canyon on-line diode array spectrophotometer to measure uranium concentrations in Tank 16.7. On-line measurements will allow an increase in highly enriched uranium (HEU) production by removing delays associated with off-line measurements. The instrument must be able to measure uranium at concentrations below 1.0 g/L with an uncertainty no greater than 0.3 g/L. SRTC determined that the system has a limit of quantitation of 0.15 g/L. At concentrations of 0.5 and 1.0 g/L, the spectrometer uncertainty is 0.10 g/L. No design changes, such as an increase in flow cell path length, are required to obtain this performance. Expected levels of iron in Tank 16.7 solutions will not interfere with the measurement. The CHEMCHEK method should not be used for confirmatory analysis, as it contributes excessively to the overall uncertainty of the measurement. SRTC expects that the spectrophotometer will meet the measurement requirements for Tank 16.7

Uranium concentration measurements in human blood for some governorates in Iraq using CR-39 track detector

International Nuclear Information System (INIS)

Tawfiq, N.F.; Ali, L.T.; Al-Jobouri, H.A.

2013-01-01

The sensitive and simple technique of fission track etch has been applied to determine trace concentration of uranium in blood samples for occupational and non-occupational workers, male and female, using CR-39 track detector that is employed for registration of induced fission tracks. The results show that the highest recorded uranium concentration in human blood of workers in the ministry of Science and Technology were 1.90 ppb (male, 36 years old, 12 years' work experience, and living in Basrah governorate) and minimum concentration 0.26 ppb (female, 40 years old, 10 years' work experience, and living in Baghdad), while for non-occupational worker, the maximum uranium concentration was 1.76 ppb (female, 63 years old, and living in Al-Muthana) and minimum concentration was 0.28 ppb (female, 20 years old, and living in Baghdad). It has also been found that the uranium concentration in human blood samples of workers in the ministry of Science and Technology are higher than those of non-occupational workers, and the uranium concentrations for female workers and for non-occupational workers were higher than those for male workers and non-occupational workers. (author)

Acid pressure leaching of a concentrate containing uranium, thorium and rare earth elements

International Nuclear Information System (INIS)

Lan Xinghua; Peng Ruqing.

1987-01-01

The acid pressure leaching of a concentrate containing rinkolite for recovering uranium, thorium and rare earth elements is described. The laboratory and the pilot plant test results are given. Under the optimum leaching conditions, the recovery of uranium, thorium and rare earth elements are 82.9%, 86.0% and 88.3% respectively. These results show that the acid pressure leaching process is a effective process for treating the concentrate

Radium and uranium concentrations and associated hydrogeochemistry in ground water in southwestern Pueblo County, Colorado

Science.gov (United States)

Felmlee, J. Karen; Cadigan, Robert Allen

1979-01-01

Radium and uranium concentrations in water from 37 wells tapping the aquifer system of the Dakota Sandstone and Purgatoire Formation in southwestern Pueblo County, Colorado, have a wide range of values and define several areas of high radioactivity in the ground water. Radium ranges from 0.3 to 420 picocuries per liter and has a median value of 8.8, and uranium ranges from 0.02 to 180 micrograms per liter and has a median value of 2.4. Radon concentrations, measured in 32 of the 37 wells, range from less than 100 picocuries per liter to as much as 27,000 and have a median value of 580. Relationships among the radioactive elements and 28 other geochemical parameters were studied by using correlation coefficients and R-mode factor analysis. Five factor groups were determined to represent major influences on water chemistry: (1) short-term solution reactions, (2) oxidation reactions, (3) hydrolysis reactions, (4) uranium distribution, and (5) long-term solution reactions. Uranium concentrations are most strongly influenced by oxidation reactions but also are affected by solution reactions and distribution of uranium in the rocks of the aquifer system. Radon and radium concentrations are mostly controlled by uranium distribution; radium also shows a moderate negative relationship with oxidation. To explain the statistical and spatial relationships among the parameters, a model was developed involving the selective leaching of uranium-bearing phases and metal sulfides which occur in discontinuous zones in sandstone and shale. When reducing conditions prevail, uranium is immobile, but radium can be taken into solution. When faults and associated fractured rocks allow oxidizing conditions to dominate, uranium can be taken into solution; radium can also be taken into solution, or it may become immobilized by coprecipitation with iron and manganese oxides or with barite. Several areas within the study area are discussed in terms of the model.

Elevated Arsenic and Uranium Concentrations in Unregulated Water Sources on the Navajo Nation, USA.

Science.gov (United States)

Hoover, Joseph; Gonzales, Melissa; Shuey, Chris; Barney, Yolanda; Lewis, Johnnye

2017-01-01

Regional water pollution and use of unregulated water sources can be an important mixed metals exposure pathway for rural populations located in areas with limited water infrastructure and an extensive mining history. Using censored data analysis and mapping techniques we analyzed the joint geospatial distribution of arsenic and uranium in unregulated water sources throughout the Navajo Nation, where over 500 abandoned uranium mine sites are located in the rural southwestern United States. Results indicated that arsenic and uranium concentrations exceeded national drinking water standards in 15.1 % (arsenic) and 12.8 % (uranium) of tested water sources. Unregulated sources in close proximity (i.e., within 6 km) to abandoned uranium mines yielded significantly higher concentrations of arsenic or uranium than more distant sources. The demonstrated regional trends for potential co-exposure to these chemicals have implications for public policy and future research. Specifically, to generate solutions that reduce human exposure to water pollution from unregulated sources in rural areas, the potential for co-exposure to arsenic and uranium requires expanded documentation and examination. Recommendations for prioritizing policy and research decisions related to the documentation of existing health exposures and risk reduction strategies are also provided.

Fission track ages and uranium concentration of apatites of different rocks of South India

International Nuclear Information System (INIS)

Nand Lal; Nagpaul, K.K.; Nagpal, M.K.

1975-01-01

The uranium concentration and ages of apatite grains of various rocks of South India have been measured by fission track technique. The ages range from 100 m.y. to 730 m.y. whereas uranium concentrations vary from 0.5 to 23.8 atom/million atoms of the apatite mineral. The ages agree well with the Deccan volcanic and Ocean Cycle activities. (author)

Domestic uranium exploration activities

International Nuclear Information System (INIS)

Chenoweth, W.L.

1980-01-01

Uranium exploration in the United States reached its alltime high in 1978 when the chief exploration indicator, surface drilling, totaled 47 million feet. In 1979, however, total drilling declined to 41 million feet, and during the first 8 months of 1980 the trend continued, as surface drilling was 27% less than for the same period in 1979. The total drilling for 1980 now is expected to be below 30 million feet, far less than the 39.4 million feet planned by industry at the beginning of the year. Falling uranium prices, the uncertainties of future uranium demand, rising costs, and the possibility of stiff foreign competition are the prime causes for the current reduction in domestic uranium exploration. Uranium exploration in the United States continues to be concentrated in the vicinity of major producing areas such as the San Juan Basin, Wyoming Basins, Texas Coastal Plain, Paradox Basin, and northeastern Washington, and in areas of recent discoveries including the Henry Mountains, Utah, the McDermitt caldera in Nevada and Oregon, and central Colorado. The distributions, by location, of total surface drilling for 1979 and the first half of 1980 are presented

The distribution of E-centres concentration in the minerals of the wall-rocks of uranium deposit

International Nuclear Information System (INIS)

Kislyakov, Ya.M.; Moiseev, B.M.; Rakov, L.T.; Kulagin, Eh.G.

1975-01-01

Electron paramagnetic resonance was used to investigate the distribution of electron-hole centres caused by natural radioactive irradiation in terrigenous arcosic rocks and their principal mineral components (quartz-feldspar concretions, white and smoky quartz, feldspars). The relationship between concentrations of E-centres and the uranium content of the rocks reflects the genetic features of the uranium mineralization. Taking one specific deposit as an example, the author shows the proportional dependence between uranium content and E-centre concentration. The dependence reflects the practically simultraneous formation of the main mass of epigenetic mineralization. The hypothesis that older (syngenetic) ore deposits may have existed was not confirmed. Despite the long interval between sedimentary accumulation end epigenesis, no significant surplus concentrations of E-centres were found in epigenetic-metamorphic rocks. Anomalous concentrations of uranium and E-centres are caused by uranium migration during later epigenetic processes superimposed on the mesozoic ore-controlling zonality. One result of this migration is the formation in limonitized rocks of ''augen'' ores for which low concentrations of paramagnetic centres are typical. For the study of the distribution of E-centres in rocks from uranium deposits, it is possible to use polymineral mixtures. For the proper interpratation of the data obtained, however, account must be taken of the sensitivity to irradiation of the various mineral components, particularly the various forms of quartz, which is the principal natural dosimeter. (E.G.)

Continuous measurement of uranium concentrations with the laser spark

International Nuclear Information System (INIS)

Gutmacher, R.G.; Cremers, D.A.; Wachter, J.R.

1987-01-01

Laser-induced breakdown spectroscopy has been applied to the continuous determination of uranium concentrations between 0.1 and 300 g/L in flowing solutions. The technique is rapid, noninvasive, and unaffected by radioactivity. A concentration of 10 g/L was measured with 0.8% precision in 3 min. Substances that absorb at the laser wavelength, suspended materials, and variations in the acidity of the solution have little or no effect on the results. High concentrations of zirconium, cadmium, aluminum, or stainless steel in solution do not interfere

Concentration of uranium in the drinking and surface water around the WIPP site

International Nuclear Information System (INIS)

Khaing, H.; Lemons, B.G.; Thakur, P.

2016-01-01

Activity concentration of uranium isotopes ( 238 U, 234 U and 235 U) were analyzed in drinking and surface water samples collected in the vicinity of the WIPP site using alpha spectroscopy. The purpose of this study was to investigate the changes in uranium concentrations (if any) in the vicinity of the WIPP site and whether the February 14, 2014 radiation release event at the WIPP had any detectable impact on the water bodies around the WIPP. (author)

New route for uranium concentrate production from Caetite ore, Bahia State, Brazil; dynamic leaching - direct precipitation

Energy Technology Data Exchange (ETDEWEB)

Morais, Carlos A. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)]. E-mail: cmorais@cdtn.br; Gomiero, Luiz A.; Scassiotti Filho, Walter [Industrias Nucleares do Brasil S.A. (INB), Caetite, BA (Brazil)]. E-mails: gomiero@inb.gov.br; scassiotti@inb.gov.br

2007-07-01

The common uranium concentrate production consists of ore leaching, uranium purification/concentration by solvent extraction and uranium precipitation as ammonium diuranate steps. In the present work, a new route of uranium concentrate production from Caetite, BA-Brazil ore was investigated. The following steps were investigated: dynamic leaching of the ground ore with sulfuric acid; sulfuric liquor pre-neutralization until pH 3.7; uranium peroxide precipitation. The study was carried out in bath and continuous circuits. In the dynamic leaching of ground ore in agitated tanks the uranium content in the leached ore may be as low as 100 {mu}g/g U{sub 3}O{sub 8}, depending on grinding size. In the pre-neutralization step, the iron content in the liquor is decreased in 99 wt.%, dropping from 3.62 g/L to 0.030 g/L. The sulfate content in the liquor reduces from 46 g/L to 22 g/L. A calcinated final product assaying 99.7 wt.% U{sub 3}O{sub 8} was obtained. The full process recovery was over 94%. (author)

Development of an on-line analyzer for organic phase uranium concentration in extraction process

International Nuclear Information System (INIS)

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

1998-10-01

The working principle, constitution, performance of an on-line analyzer and the development characteristic of immersion sonde, data processing system and examination standard are reported. The performance of this instrument is reliable. For identical sample, the signal fluctuation in continuous monitoring for four months is less than +-1%. According to required measurement range by choosing appropriate length of sample cell the precision of measurement is better than 1% at uranium concentration 100 g/L. The detection limit is (50 +- 10) mg/L. The uranium concentration in process stream can be automatically displayed and printed out in real time and 4∼20 mA current signal being proportional to the uranium concentration can be presented. So the continuous control and computer management for the extraction process can be achieved

Uranium hydrogeochemical and stream sediment reconnaissance of the Gillette NTMS quadrangle, Wyoming, including concentrations of forty-two additional elements

International Nuclear Information System (INIS)

Warren, R.G.; George, W.E.; Minor, M.M.; Simi, O.R.; Talcott, C.L.; Hensley, W.K.; Cheadle, J.M. III.

1980-08-01

During 1976 and 1977, 752 water and 843 sediment samples were collected from 1419 locations within the 17 700-km 2 area of the Gillette quadrangle, Wyoming. Water samples were collected primarily from wells, and also from springs, ponds, and streams; sediment samples were collected primarily from stream channels, and also from springs and ponds. Each water sample was analyzed for uranium and each sediment sample was analyzed for 43 elements, including uranium and thorium. Uranium concentrations in water samples range from below the detection limit of 0.02 to 212.20 ppB and have a median of 1.10 ppB. The highest background uranium concentrations, as well as the highest individual uranium values, are in areas where favorable host units for uranium mineralization crop out. These units are the Wasatch and Fort Union formations in the Powder River Basin and the Inyan Kara group in the Black Hills. Uranium concentrations in sediment samples range from 0.64 to 29.83 ppM and have a median of 3.24 ppM. Background uranium concentrations are strongly controlled by the exposed geologic unit, and range from 4 to 8 ppM for the Cretaceous Colorado group to 1 to 3 ppM for the Triassic and Paleozoic units exposed in the Black Hills. Several areas where the Wasatch and Fort Union formations are exposed exhibit uranium concentrations in sediment samples that are slightly, but distinctly, above background values for these units. All of these areas are also associated with notably high uranium concentrations in water samples. Because epigenetic uranium mineralization in economically important areas can exhibit a similar geochemical signature, these areas within the Gillette quadrangle should be further examined for the possible presence of uranium mineralization

Ecological change drives a decline in mercury concentrations in southern Beaufort Sea polar bears

Science.gov (United States)

McKinney, Melissa A.; Atwood, Todd C.; Pedro, Sara; Peacock, Elizabeth

2017-01-01

We evaluated total mercury (THg) concentrations and trends in polar bears from the southern Beaufort Sea subpopulation from 2004 to 2011. Hair THg concentrations ranged widely among individuals from 0.6 to 13.3 μg g–1 dry weight (mean: 3.5 ± 0.2 μg g–1). Concentrations differed among sex and age classes: solitary adult females ≈ adult females with cubs ≈ subadults > adult males ≈ yearlings > cubs-of-the-year ≈ 2 year old dependent cubs. No variation was observed between spring and fall samples. For spring-sampled adults, THg concentrations declined by 13% per year, contrasting recent trends observed for other Western Hemispheric Arctic biota. Concentrations also declined by 15% per year considering adult males only, while a slower, nonsignificant decrease of 4.4% per year was found for adult females. Lower THg concentrations were associated with higher body mass index (BMI) and higher proportions of lower trophic position food resources consumed. Because BMI and diet were related, and the relationship to THg was strongest for BMI, trends were re-evaluated adjusting for BMI as the covariate. The adjusted annual decline was not significant. These findings indicate that changes in foraging ecology, not declining environmental concentrations of mercury, are driving short-term declines in THg concentrations in southern Beaufort Sea polar bears.

Uranium concentrations and 234U/238U activity ratios in fault-associated groundwater as possible earthquake precursors

International Nuclear Information System (INIS)

Finkel, R.C.

1981-01-01

In order to assess the utility of uranium isotopes as fluid phase earthquake precursors, uranium concentrations and 234 U/ 238 U activity ratios have been monitored on a monthly or bimonthly basis in water from 24 wells and springs associated with Southern California fault zones. Uranium concentrations vary from 0.002 ppb at Indian Canyon Springs on the San Jacinto fault to 8.3 ppb at Lake Hughes well on the San Andreas fault in the Palmdale area. 234 U/ 238 U activity ratios vary from 0.88 at Agua Caliente Springs on the Elsinore fault to 5.4 at Niland Slab well on the San Andreas fault in the Imperial Valley. There was one large earthquake in the study area during 1979, the 15 October 1979 M = 6.6 Imperial Valley earthquake. Correlated with this event, uranium concentrations varied by a factor of more than 60 and activity ratios by a factor of 3 at the Niland Slab site, about 70 km from the epicenter. At the other sites monitored, uranium concentrations varied in time, but with no apparent pattern, while uranium activity ratios remained essentially constant throughout the monitoring period

Process for the winning of a concentrate containing uranium and purified phosphoric acid, as well as the concentrate containing uranium and purified phosphoric acid obtained by this process

International Nuclear Information System (INIS)

1980-01-01

The uranium containing concentrate and purified phosphoric acid are obtained by treating wet phosphoric acid with an inorganic fluorine compound (ammonium fluoride) and an aliphatic ketone (acetone) in the presence of a reducing agent (finely divided iron). The ketone is added first and the formed uranium precipitate is separated from the solution. If the fluorine compound is added first, the yield is lowered by a factor of 2. (Th.P.)

A study on prediction of uranium concentration in pregnant solution from in-situ leaching

International Nuclear Information System (INIS)

Yi Weiping; Zhou Quan; Yu Yunzhen; Wang Shude; Yang Yihan; Lei Qifeng

2005-01-01

The modeling course on prediction of uranium concentration in pregnant solution from in-situ leaching of uranium is described, a mathematical model based on grey system theory is put forward, and a set of computer application software is correspondingly developed. (authors)

Collection/concentration of trace uranium for spectrophotometric detection using activated carbon and first-derivative spectrophotometry

International Nuclear Information System (INIS)

El-Sayed, A.A.; Hamed, M.M.; El-Reefy, S.; Hmmad, H.A.

2007-01-01

The need exists for preconcentration of trace and ultratrace amounts of uranium from environmental, geological and biological samples. The adsorption of uranium on various solids is important from the purification, environmental, and radioactivity waste disposal points of view. A method is described for the determination of traces of uranium using first-derivative spectrophotometry after adsorptive preconcentration of uranium on activated carbon. Various parameters that influence the adsorptive preconcentration of uranium on activated carbon, viz., pH, amounts of activated carbon and time of stirring and interference of metals have been studied. First-derivative spectrophotometry in conjunction with adsorptive preconcentration of uranium on activated carbon is used for determining uranium at concentration levels down to 20 ppb (w/v). (orig.)

Behaviour of the pH adjustment, Ion exchange and concentrate precipitation stages in the acid leaching of uranium phosphate ores

International Nuclear Information System (INIS)

Estrada Aguilar, J.; Uriarte Hueda, A.

1962-01-01

The uranium recovery from acid leach solutions of uranium-phosphate ores has been studied. Relations have been found between the solution characteristics and the results obtained at different stages of the process. The following data can thus be predicted: solids to remove and uranium recovery in the pH adjustment stage, uranium capacity of the resin, more suitable eluating agent, elution velocity and uranium concentration in the eluate in the ion exchange stage, and composition of the concentrate produced by direct precipitation of the eluate in the concentrate precipitation stage. (Author) 8 refs

Determination of 226Ra and natural uranium concentration in Botafogo river

International Nuclear Information System (INIS)

Nascimento, M.B. do; Amaral, R.S.; Khoury, H.J.; Andrade Lima, R. de

1990-01-01

In the Brazilian Northeast region at the coastal area from Pernambuco to Paraiba there is a 4 km wide strip deposit of phosphate rock. This phosphate is used to produce fertilizes by a factory located at the border of the Botafogo river, which cross this area. The phosphate is associated with uranium and no research has been conducted on the river radioactive contamination due the natural processes and to the fertizer factory the present investigation was undertaken to determine 226 Ra and natural uranium concentration in the river water, near the factory. Results show that the radionuclide concentration increases sharply in front of the place of the factory discharge and then decreases rapidly to the same levels found before the factory, 0,01 Bq/1. (author) [pt

Investigation into sorption of uranium fron its high-concentrated nitric acid solutions on resin AMP

International Nuclear Information System (INIS)

Savel'eva, V.I.; Sudarikov, B.N.; Kireeva, G.N.; Ryzhkova, V.N.; Kandaryuk, V.V.

1976-01-01

Sorption of uranium has been studied on strongly basic anion-exchange resin from nitric acid solutions with concentration in metal 10-150 g/l in presence of sodium, calcium, and aluminium nitrates. Sorption of uranium from solutions has been performed by the static method with the aid of contacting the initial solution with airdry resin for 4 hours, resin to solution ratio being 1:12.5. It has been established that sorption of uranium increases with a rise in concentration of salting out agents in the following order: Al(NO 3 ) 3 > Ca(NO 3 ) 2 > Na(NO 3 ). It has been shown spectrophotometricatly that in solutions of nitrates and HNO 3 with a concentration 3 exceeds 6 mol/l

Hydrochloric acid leach of Agnew Lake uranium concentrate

International Nuclear Information System (INIS)

Haque, K.E.; Ipekoglue, B.

1981-10-01

Hydrochloric acid leaching was conducted on the radioactive mineral concentrate separated from the Agenw Lake uranium ore. Leach tests conducted at the optimum conditions (75 0 C; 36 hours; 66.0 Kg HCl/tonne; solid:liquid -1:1) resulted in the extraction of 87% uranium and 84% radium. The radionuclide level of the residue was U-0.016%, Th-0.24% and Ra-65 pCi/g solids. However to obtain a residue almost free of radium (i.e., Ra level at the detection limit: 4-6 pCi/g solids), the first stage leach residue was further treated with hydrochloric acid. The radium level in the best second stage leach residue was also above the target level. Therefore, multistage (3 or 4) hydrochloric acid and/or neutral chloride leaching is recommended to obtain tailings almost free of radionuclide

Development of uranium industry in Romania

International Nuclear Information System (INIS)

Iuhas, Tiberiu

2000-01-01

The management of the uranium resources is performed in Romania by the National Uranium Company. The tasks to be done are: 1. management and protection of rare and radioactive metal ores in the exploitation areas; 2. mining, preparation, refining and trading the radioactive ores, as well as reprocessing the uranium stock from the uranium concentrate in the national reserve; 3. performing geologic and technologic studies in the exploitation areas; 4. performing studies and projects concerning the maintenance of the present facilities and unearthing new ores; 5. building industrial facilities; 6. carrying out technological transport; 7. importation-exportation operations; 8. performing micro-production activity in experimental research units; 9. personnel training; 10. medical assistance for the personnel; 11. environment protection. The company is organized as follows: 1.three branches for uranium ore mining, located at Suceava, Bihor and Banat; 2. one branch for geologic survey, located at Magurele; 3. one branch for uranium ore preparation and concentration and for refining uranium concentrates, located at Feldioara; 4. One group for mine conservation, closure and ecology, located at Bucuresti. The final product, sintered powder of UO 2 produced at Feldioara plant, was tested in 1994 by the Canadian partner and met successfully the required standards. The Feldioara plant was certified as supplier of raw material for CANDU nuclear fuel production and as such, Romania is the only authorized producer of CANDU nuclear fuel in Europe and the second in the world, after Canada. Maintaining the uranium production in Romania is justified by the existence of uranium ore resources, the declining of natural gas resources, lower costs per kWh for electric nuclear power as compared to fossil-fuel power production, the possibility for Romania to become an important supplier of CANDU nuclear fuel, the low environmental impact and high costs for total shutdown of activity, high

Removing ferric ions from concentrated acid leaching solution of an uranium ore by jarosite

International Nuclear Information System (INIS)

Song Huanbi; Hu Yezang

1997-01-01

The author expounds the fundamental rules of removing ferric ions by jarosite and presents results of removing ferric ions from concentrated acid curing-trickle leaching solution of an uranium ore. It turns out that the method can be applied to uranium hydrometallurgical process effectively

Determination of the uranium concentration in soil solutions by the fission track registration technique

International Nuclear Information System (INIS)

Fernandes, G.P.

1980-02-01

The fission tracks registration technique was used to determine the uranium concentration in soil solutions. The Makrofol KG, a synthetic plastic manufactured by Bayer, was used as a detector and the wet method was applied. From the calibration curves obtained, it was possible to determine uranium concentrations in soil solutions, from 90 to 320 μg U/l, with an error between 9.4% and 4.0%, respectively. The method was applied to a few soil samples from Pocos de Caldas, Minas Gerais in Brazil. The uranium concentrations in the sample and residues were also determined by other methods to compare the results obtained; only one sample showed deviation from the results obtained by the fission tracks method. And this discrepancy was explained in a reasonable way. It was shown that the fission tracks technique can be used with sucess for application in soil solutions. (Author) [pt

Uranium recovery from the concentrated phosphoric acid prepared by the hemi-hydrate process

Energy Technology Data Exchange (ETDEWEB)

Fouad, E A; Mahdy, M A; Bakr, M Y [Nuclear materials authority, Cairo, (Egypt); Zatout, A A [Faculty of engineering, Alex. university, Alex, (Egypt)

1995-10-01

It has been proved that the uranium dissolution from El-sebaiya phosphate ore was possible by using 10 Kg of K Cl O{sub 4}/ ton rock during the preparation of high strength phosphoric acid using the hemi hydrate process. In the present work, effective extraction of uranium (about 90%) from the high strength phosphoric acid using a new synergistic solvent mixture of 0.75 M D 2 EHPA/0.1 M TOHPO had been a success. Stripping of uranium from the organic phase was possible by 10 M phosphoric acid while the direct precipitation of uranium concentrate from the later was feasible by using N H{sub 4} F in presence of acetone. 8 figs.

Uranium recovery from the concentrated phosphoric acid prepared by the hemi-hydrate process

International Nuclear Information System (INIS)

Fouad, E.A.; Mahdy, M.A.; Bakr, M.Y.; Zatout, A.A.

1995-01-01

It has been proved that the uranium dissolution from El-sebaiya phosphate ore was possible by using 10 Kg of K Cl O 4 / ton rock during the preparation of high strength phosphoric acid using the hemi hydrate process. In the present work, effective extraction of uranium (about 90%) from the high strength phosphoric acid using a new synergistic solvent mixture of 0.75 M D 2 EHPA/0.1 M TOHPO had been a success. Stripping of uranium from the organic phase was possible by 10 M phosphoric acid while the direct precipitation of uranium concentrate from the later was feasible by using N H 4 F in presence of acetone. 8 figs

Groundwater radon, radium and uranium concentrations in Regiao dos Lagos, Rio de Janeiro State, Brazil

International Nuclear Information System (INIS)

Almeida, R.M.R.; Lauria, D.C.; Ferreira, A.C.; Sracek, O.

2004-01-01

Ground water from Regiao dos Lagos, a coastal area of Rio de Janeiro state, was analysed for 226 Ra, 228 Ra, 222 Rn, 238 U, major ion concentrations, and physico-chemical parameters were also measured. Concentrations values ranged from -1 for 226 Ra, from -1 for 228 Ra and from -4 to 8.0x10 -2 Bq l -1 for 238 U. Detectable 222 Rn concentrations (>3 Bq l -1 ) were found only in two samples. The spatial distribution of Ra concentration delineated one distinct area and some hot spots with high Ra concentration. Low pH value is the most important water parameter linked to high radium concentration. This is probably related to limited adsorption of radium on soil ferric oxides and hydroxides at low pH range. There was a significant correlation between uranium concentrations and electrical conductivity values, and also between uranium concentrations and concentrations of Ca, Mg, Na, K, and Cl, indicating sea water impact. Uranium concentrations were lower than maximum contaminant level for drinking water, whereas 17 out of the 88 ground water samples had levels of radium that exceeded the maximum contaminant level for tap water. The total annual effective dose for adult due to the water consumption reaches values up to 0.8 mSv

Uranium concentrate analysis by X-ray fluorescence spectroscopy

International Nuclear Information System (INIS)

Diaz-Guerra, J.P.; Bayon, A.; Roca, R.

1978-01-01

The determination of As, Ca, Fe, Mo, P, S, Si. Th, V and U in uranium concentrates by X-ray fluorescence spectroscopy has been studied. As and U are determined in nitric solutions and for the rest of elements analysis is performed by a bead fusion technique using Li 2 B 4 O 7 and Li 2 CO 3 as fluxes. Although the uranium matrix minimizes the absorption and enhancement effects, because of the content variations of this element it is advisable to operate at a constant level of U 3 O 8 . Despite the high matrix absorption and the large dilution of the samples, sensitivity and speed are found to be satisfactory as the result of the use of a high sensitivity automatic spectrometer. The spectral interferences of Mo on S and P, and of Pb on As have been particularly considered. (author) [es

Determination Of Uranium Concentration In Teeth Female Samples Using Fission Tracks In CR-39 From Different Countries

International Nuclear Information System (INIS)

Hummadi, S.S

2010-01-01

The present study was under taken to measure the uranium concentration in female teeth samples collected from different nationalities.The determination of uranium concentration in these samples has been done by using CR-39 track detector.The nuclear reaction is used as a source of nuclear fission fragments is (n, f) obtained by the bombardment of U-235 with thermal neutrons with flux (5*10 3 n/cm 2 .s) was used from (Am-Be) neutron source.The obtained results show the concentration is ranging from (0.58±0.7ppm) in Oman and Uae to (0.35±0.03ppm)in Iraqi for male, the uranium concentration was the highest in Oman and Uae for female

How would a decline in sperm concentration over time influence the probability of pregnancy?

DEFF Research Database (Denmark)

Slama, R.; Jensen, Tina Kold; Scheike, T.

2004-01-01

BACKGROUND: Reports have suggested a decline in sperm concentration during the second half of the 20th century. The effect of this decline on fecundability (the monthly probability of pregnancy) could be detected in principle by a study of time to pregnancy. In practice, the amplitude of this exp......BACKGROUND: Reports have suggested a decline in sperm concentration during the second half of the 20th century. The effect of this decline on fecundability (the monthly probability of pregnancy) could be detected in principle by a study of time to pregnancy. In practice, the amplitude...... of this expected effect is not well known and the statistical power of time-to-pregnancy studies to detect it has not been explored. METHODS: We developed a nonparametric model to describe a temporal decline in sperm concentration using data on French semen donors. We then applied this model to 419 Danish couples...... planning a first pregnancy in 1992, to predict their time to pregnancy as if the pregnancy attempt had begun during earlier decades with higher sperm concentrations. Finally, we used bootstrap simulations to estimate the statistical power of prospective or retrospective studies that compared fecundability...

Nannoplankton and uranium concentration relations in the Black Sea Deposits

Directory of Open Access Journals (Sweden)

Vedia TOKER

1983-12-01

Full Text Available Nannoplanktons obtained from sixty-two core samples taken from twenty-three holes penetrated in the Southern part of Black Sea were investigated in this work. Twelve species belonging to the Emiliania huxleyi zone (NN 21-Holocene were determined. Emiliania huxleyi (Lohmann came into existence in Black Sea three thousand years ago and is very abundant in these sediments. This study clearly showed that uranium concentration increases with increasing nannoplankton content of the sediments. It is also observed that the uranium oxide (U3O8 contents of the Emiliania huxleyi (Lohmann accumulations on the abyssal plains are higher than those other sediments in the same environments.

Determination of uranium concentration and burn-up of irradiated reactor fuel in contaminated areas in Belarus using uranium isotopic ratios in soil samples

International Nuclear Information System (INIS)

Mironov, V.P.; Matusevich, J.L.; Kudrjashov, V.P.; Ananich, P.I.; Zhuravkov, V.V.; Boulyga, S.F.; Becker, J.S.

2005-01-01

An analytical method is described for the estimation of uranium concentrations, of 235 U/ 238 U and 236 U/ 238 U isotope ratios and burn-up of irradiated reactor uranium in contaminated soil samples by inductively coupled plasma mass spectrometry. Experimental results obtained at 12 sampling sites situated on northern and western radioactive fallout tails 4 to 53 km distant from Chernobyl nuclear power plant (NPP) are presented. Concentrations of irradiated uranium in the upper 0-10 cm soil layers at the investigated sampling sites varied from 2.1 x 10 -9 g/g to 2.0 x 10 -6 g/g depending mainly on the distance from Chernobyl NPP. A slight variation of the degree of burn-up of spent reactor uranium was revealed by analyzing 235 U/ 238 U and 236 U/ 238 U isotope ratios and the average value amounted to 9.4±0.3 MWd/(kg U). (orig.)

Determination of uranium concentration and burn-up of irradiated reactor fuel in contaminated areas in Belarus using uranium isotopic ratios in soil samples

Energy Technology Data Exchange (ETDEWEB)

Mironov, V.P.; Matusevich, J.L.; Kudrjashov, V.P.; Ananich, P.I.; Zhuravkov, V.V. [Inst. of Radiobiology, Minsk Univ. (Belarus); Boulyga, S.F. [Inst. of Inorganic Chemistry and Analytical Chemistry, Johannes Gutenberg-Univ. Mainz, Mainz (Germany); Becker, J.S. [Central Div. of Analytical Chemistry, Research Centre Juelich, Juelich (Germany)

2005-07-01

An analytical method is described for the estimation of uranium concentrations, of {sup 235}U/{sup 238}U and {sup 236}U/{sup 238}U isotope ratios and burn-up of irradiated reactor uranium in contaminated soil samples by inductively coupled plasma mass spectrometry. Experimental results obtained at 12 sampling sites situated on northern and western radioactive fallout tails 4 to 53 km distant from Chernobyl nuclear power plant (NPP) are presented. Concentrations of irradiated uranium in the upper 0-10 cm soil layers at the investigated sampling sites varied from 2.1 x 10{sup -9}g/g to 2.0 x 10{sup -6}g/g depending mainly on the distance from Chernobyl NPP. A slight variation of the degree of burn-up of spent reactor uranium was revealed by analyzing {sup 235}U/{sup 238}U and {sup 236}U/{sup 238}U isotope ratios and the average value amounted to 9.4{+-}0.3 MWd/(kg U). (orig.)

Maximum permissible concentrations of uranium in air

CERN Document Server

Adams, N

1973-01-01

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

Anomalously high concentrations of uranium, radium and radon in water from drilled wells in the Helsinki region

International Nuclear Information System (INIS)

Asikainen, M.; Kahlos, H.

1979-01-01

The concentrations of uranium, 226 Ra and 222 Rn were determined in 308 drilled and 58 dug wells in the Helsinki region. The study area was about 400 km 2 and geologically highly variable, with granites, amphibolites and migmatites the dominant rocks. The radioactivity of water in the dug wells was on a 'normal' level, but in numerous drilled wells it was anomalously high. In 14 drilled wells the concentration of uranium exceeded 1000 μg/l, the highest concentration being 14,870 μg/l. For 222 Rn the maximum concentration was 880,000 pCi/l. The 226 Ra/ 228 Ra and 230 Th/ 232 Th activity ratios showed the isotopes of the uranium series to be dominant in the study area. A state of disequilibrium between 238 U and 234 U was very common in the samples. The 234 U/ 238 U activity ratios varied in the range 1.0 to 4.0 regardless of the amount of uranium in the water. The conclusion can be drawn from the isotopic data that the high radioactivity of water is in some cases caused by primary uranium mineralizations, but mostly by uranium deposited in fissures of the bedrock. The paper includes a summary of the results of two studies carried out between 1967 and 1977. (author)

Concentration of uranium on TiO-PAN and NaTiO-PAN composite absorbers

International Nuclear Information System (INIS)

Motl, Alois; Sebesta, Ferdinand; John, Jan; Spendlikova, Irena; Nemec, Mojmir

2013-01-01

Inorganic ion exchangers have been extensively tested for use in separation and concentration of uranium from Surface water. Except for separation of uranium from uranium -Contaminated waste water (e.g. waste water from mining and milling of uranium, Waste from nuclear fuel reprocessing) their main area of application has been foreseen to be their use for extraction of uranium from sea water which could partially cover future needs of uranium. Another perspective area of application is pre-concentration of uranium from natural waters followed by uranium determination via various specialized techniques such as TRLFS or AMS. Possibilities of uranium extraction from sea water have been subject of several international conferences (e.g. Topical meetings on the Recovery of Uranium from Seawater in 1980's, ACS National Meetings 2012 etc.) and are critically evaluated in a review by Bitte or recently by Kim. In the Czech Republic uranium-selective inorganic ion exchangers might be applied for treatment of various wastes from uranium industry, namely underground Water, uranium milling over-balance water, or acid waste water from underground uranium leaching and also like in other countries for determination of uranium isotopic composition focusing on anthropogenic and natural 236 U content. Among the best performing inorganic ion exchangers for the above listed purposes hydrated titanium dioxide (abbreviated as TiO) and sodium titanate (abbreviated as NaTiO) can be listed. Properties of TiO and NaTiO were reviewed by Lehto. From the point of view of ion-exchange, properties of hydrated titanium oxide and sodium titanate are very similar. The main disadvantage of these ion exchangers for industrial-scale application is their insufficient mechanical stability. To improve this property, the sorption materials can be embedded into a binding matrix. Modified polyacrylonitrile (PAN) has been proposed at the Czech Technical University in Prague as a universal binding matrix for

Concentration of Uranium levels in groundwater

International Nuclear Information System (INIS)

Babu, M. N. S.; Somashekar, R. K.; Kumar, S. A.; Shivanna, K.; Krishnamurthy, V.; Eappen, K. P.

2008-01-01

The uranium isotopes during their course of their disintegration decay into other radioactive elements and eventually decay into stable lead isotopes. The cause of environmental concern is the emanation of beta and gamma radiation during disintegration. The present study tends to estimate uranium in groundwater trapped in granite and gneiss rocks. Besides, the study aims at estimating the radiation during natural disintegration process. The water samples were collected and analyzed following inductively coupled plasma mass spectrometric technique while water sample collection was given to the regions of Kolar District, South India, due to the representation. The significant finding was the observation of very high levels of uranium in groundwater compared to similar assays reported at other nearby districts. Also, the levels were considerable to those compared to groundwater levels of uranium reported by other scientists, On the basis of this study, it was inferred that the origin of uranium was from granite strata and there was a trend of diffusion observed in the course of flow-path of water in the region

Evaluation of the precision in fluoride determination in uranium concentrate

International Nuclear Information System (INIS)

Palmieri, Helena E. Leonhardt; Rocha, Zildete; Mata, Maria Olivia Cintra

1995-01-01

The fluoride in uranium concentrate is previously separated by steam distillation and then determined by direct potentiometric with an ion-select electrode. The potential of all ion-specific electrodes is a logarithmic function of the concentration of the ion to which the electrode in question responds. This relationship is expressed by the Nernst equation. A calibration curve, potential (mV) versus standard fluoride concentration is established and then the sample concentration is determined by interpolation. A least squares curve-fitting procedure has been used to determine the parameters of this calibration curve equation. Using these parameters are determined the standard deviation, the confidence limits and the precision of the fluoride concentrations. (author). 3 refs., 2 figs., 1 tab

Characterization and classification of uranium ore concentrates (yellow cakes) using infrared spectrometry

Energy Technology Data Exchange (ETDEWEB)

Varga, Z.; Oeztuerk, B.; Mayer, K.; Wallenius, M.; Apostolidis, C. [Joint Research Centre, Karlsruhe (Germany). Inst. for Transuranium Elements; Meppen, M. [Carl Friedrich von Weizsaecker-Zentrum fuer Naturwissenschaft und Friedensforschung, Hamburg (Germany)

2011-07-01

In this work the applicability of Fourier-transform infrared spectrometry (FTIR) for nuclear forensic studies of uranium ore concentrates (UOC) are investigated. The technique was used for the identification of the type of uranium compound and various process-related impurities, which can give information on the production method of the material. The measured spectra were evaluated also by statistical means, using the soft independent modelling of class analogy (SIMCA) technique to reveal less apparent similarities between the measured UOC samples.

The effect of different uranium concentrations on physiological characteristics and chlorophyll contents in sunflowers and soy bean

International Nuclear Information System (INIS)

Bagherifam, S.; Lakzian, A.; Ahmadi, S. J.; Fotovat, A.; Rahimi, M. F.

2009-01-01

Uranium as a natural radioactive heavy metal, widely disperses throughout the earth's crust. In many cases, the natural abundance has been re-distributed due to anthropogenic activities, resulting in radionuclide contamination in groundwater and surface soil. A pot experiment had been conducted in the Agricultural College Research Greenhouse, at the Ferdowsi University of Mashhad under the controlled condition. The effect of six levels of uranium (0, 50, 100, 250, 500 and 1000 mg U kg -1 ) on physiological characteristics and chlorophyll contents in sunflower and soy bean were studied in a completely randomized design as a factorial experiment with three replications. Plants were harvested after 40 days and before the reproductive stages. Root and stem length, root dry weight, stem dry weight, biomass and chlorophyll contents were determined. The shoot and root length, fresh and dry mass as well as leaf area and chlorophyll contents showed a significant negative correlation with the applied uranium concentrations. The influence on plant growth was also measured in terms of tolerance index and grade of growth inhibition. The results showed that tolerance index increased and grade od growth inhibition decreased with the applied uranium concentration. Biomass and tolerance of sunflower during the experiment on higher uranium concentrations showed that sun flower is more resistant against uranium toxicity

Concentration of uranium in human cancerous tissues of Southern Iraqi patients using fission track analysis

International Nuclear Information System (INIS)

Al-Hamzawi, A.A.; Al-Qadisiyah University, Qadisiyah; Jaafar, M.S.; Tawfiq, N.F.

2015-01-01

The technique of nuclear fission track analysis with solid state nuclear track detectors CR-39 has been applied to determine concentrations of uranium in cancerous samples of human tissues that excised from patients in the three key southern Iraqi governorates namely, Basrah, Dhi-Qar, and Muthanna. These provinces were the sites of intensive military events during the Gulf Wars in 1991 and 2003. The investigation was based on the study of 24 abnormal samples and 12 normal samples for comparing the results. These samples include four types of soft tissues (kidney, breast, stomach and uterus). The results show that uranium concentrations in the normal tissues ranged between (1.42-4.76 μg kg -1 ), whereas in the cancerous tissues ranged between (3.37-7.22 μg kg -1 ). The uranium concentrations in the normal tissues were significantly lower than in the abnormal tissues (P < 0.001). (author)

Ecological, economical and social impact of uranium mining activity on local communities in the area of Banat-Oravita branch of National Uranium Company

International Nuclear Information System (INIS)

Cocar, D.; Grigorita, L.

2000-01-01

In this work, the ecological, economical and social effects of uranium mining activity on environment and local communities in Caras Severin county are considered. 4412 radiochemical analyses and about 6730 radiometric measurements were made. The waters of local rivers were found to be contaminated with natural uranium and 226 radium, but the biological risk is not significant. Their concentrations and effective doses are presented in 8 tables referring to the rivers Lisava, Jitin, Caras. Also, samples of water from springs and wells in the Banat mining area were analysed for natural uranium and 226 Ra, their concentrations being found under the maximum permissible level. The air quality was not affected by accidental radon emissions. In order to limit the ecological impact on the environment, remedial action measures are proposed. The economic and social impact on the local communities are due mainly to the decline of activity, the most important effect being the unemployment

Uranium conversion

International Nuclear Information System (INIS)

Oliver, Lena; Peterson, Jenny; Wilhelmsen, Katarina

2006-03-01

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

Uranium exploration

International Nuclear Information System (INIS)

De Voto, R.H.

1984-01-01

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

Uranium concentration in drinking water from small-scale water supplies in Schleswig-Holstein, Germany; Urankonzentration im Trinkwasser aus Hausbrunnen in Schleswig-Holstein

Energy Technology Data Exchange (ETDEWEB)

Ostendorp, G. [Landesamt fuer soziale Dienste, Kiel (Germany). Dezernat Umweltbezogener Gesundheitsschutz

2015-07-01

In this study the drinking water of 212 small-scale water supplies, mainly situated in areas with intensive agriculture or fruit-growing, was analysed for uranium. The median uranium concentration amounted to 0.04 μg/lL, the 95th percentile was 2.5 μg/L. The maximum level was 14 μg/L. This sample exceeded the guideline value for uranium in drinking water. The uranium concentration in small-scale water supplies was found to be slightly higher than that in central water works in Schleswig-Holstein. Water containing more than 10 mg/L nitrate showed significantly higher uranium contents. The results indicate that the uranium burden in drinking water from small wells is mainly determined by geological factors. An additional anthropogenic effect of soil management cannot be excluded. Overall uranium concentrations were low and not causing health concerns. However, in specific cases higher concentrations may occur.

Evaluating the reliability of uranium concentration and isotope ratio measurements via an interlaboratory comparison program

International Nuclear Information System (INIS)

Oliveira Junior, Olivio Pereira de; Oliveira, Inez Cristina de; Pereira, Marcia Regina; Tanabe, Eduardo

2009-01-01

The nuclear fuel cycle is a strategic area for the Brazilian development because it is associated with the generation of electricity needed to boost the country economy. Uranium is one the chemical elements in this cycle and its concentration and isotope composition must be accurately known. In this present work, the reliability of the uranium concentration and isotope ratio measurements carried out at the CTMSP analytical laboratories is evaluated by the results obtained in an international interlaboratory comparison program. (author)

Uranium hydrogeochemical and stream sediment reconnaissance of the vernal NTMS quadrangle, Utah/Colorado, including concentrations of forty-two additional elements

International Nuclear Information System (INIS)

Purson, J.D.

1980-08-01

The Los Alamos Scientific Laboratory conducted a geochemical reconnaissance for uranium in the Vernal NTMS quadrangle, Utah/Colorado, in the summers of 1977 and 1978. Totals of 422 water and 1552 sediment samples were collected from 1652 locations. These samples were collected at an average density of one sample location per 11 km 2 over an 18,800 km 2 area. Water samples were collected from streams and springs. Only those samples containing >10 ppB uranium for waters and >8 ppM uranium for sediments are discussed; however, all field and analytical data are included in the appendixes. The uranium concentrations in waters range from below the detection limit of 0.01 ppB to 108.04 ppB, with a mean uranium concentration for all water types of 3.11 ppB. Three clusters of samples containing relatively high uranium values are defined; they are associated with the Duchesne River formation, the Mancos shale, or the Uinta Mountain group and Browns Park formations. A few of the samples having the highest uranium values are associated with host rocks favorable for significant uranium mineralization. Sediments collected in this study have uranium concentrations that range between 0.70 ppM and 56.70 ppM, with a mean of 3.46 ppM. The majority of sediment samples with relatively high uranium concentrations were collected from one area in the Sand Wash basin in the northeastern corner of the quadrangle and are associated with the Wasatch formation. None of the water clusters define areas of significant interest; however, the area having high uranium values in sediments is worthy of further study

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

Science.gov (United States)

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

2015-12-01

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

Natural uranium concentrations of native plants over a low-grade ore body

International Nuclear Information System (INIS)

Sheppard, M.I.; Thibault, D.H.

1984-01-01

Plant uranium concentrations generally reflect soil or rock substrate concentrations in upland areas, but they may not in lowland areas where the rhizoids of Sphagnum spp. and rocks of Ledum groenlandicum may be in direct contact either continuously or on a seasonal basis with the groundwater. This study points out the importance of selecting plant species and collection sites where the true substrate can be well defined and sampled. Sphagnum spp. and Ledum groenlandicum best reflect the substrate uranium concentrations in lowland areas, Umbilicaria spp. and Cladonia spp. in rock outcrop, and Picea mariana and Betula papyrifera in upland locations. The study shows the best plant part to sample is the older tissue such as the stems, twigs, and wood. Since no systematic changes in plant tissue concentrations were found throughout the season, sampling can be carried out anytime. Expression of soil concentrations on an ash weight basis gave a considerably different result than those on a dry weight basis, particularly when comparisons were made between litter-enriched mineral soil and true organic soils. The amount of ash varied among plant organs, species, and taxonomic divisions, and a constant value cannot be used to convert plant ash concentrations on a dry weight basis

Effect of pH and Pressure on Uranium Removal from Drinking Water Using NF/RO Membranes.

Science.gov (United States)

Schulte-Herbrüggen, Helfrid M A; Semião, Andrea J C; Chaurand, Perrine; Graham, Margaret C

2016-06-07

Groundwater is becoming an increasingly important drinking water source. However, the use of groundwater for potable purposes can lead to chronic human exposure to geogenic contaminants, for example, uranium. Nanofiltration (NF) and reverse osmosis (RO) processes are used for drinking water purification, and it is important to understand how contaminants interact with membranes since accumulation of contaminants to the membrane surface can lead to fouling, performance decline and possible breakthrough of contaminants. During the current study laboratory experiments were conducted using NF (TFC-SR2) and RO (BW30) membranes to establish the behavior of uranium across pH (3-10) and pressure (5-15 bar) ranges. The results showed that important determinants of uranium-membrane sorption interactions were (i) the uranium speciation (uranium species valence and size in relation to membrane surface charge and pore size) and (ii) concentration polarization, depending on the pH values. The results show that it is important to monitor sorption of uranium to membranes, which is controlled by pH and concentration polarization, and, if necessary, adjust those parameters controlling uranium sorption.

Uranium production in thorium/denatured uranium fueled PWRs

International Nuclear Information System (INIS)

Arthur, W.B.

1977-01-01

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

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)

Uranium and thorium concentration process during partial fusion and crystallization of granitic magma

International Nuclear Information System (INIS)

Cuney, M.

1982-01-01

Two major processes, frequently difficult to distinguish, lead to uranium and thorium enrichment in igneous rocks and more particularly in granitoids; these are partial melting and fractional crystallization. Mont-Laurier uranothoriferous pegmatoids, Bancroft and Roessing deposits are examples of radioelement concentrations resulting mostly of low grade of melting on essentially metasedimentary formations deposited on a continental margin or intracratonic. Fractional crystallization follows generally partial melting even in migmatitic areas. Conditions prevailing during magma crystallization and in particular oxygen fugacity led either to the formation of uranium preconcentrations in granitoids, or to its partition in the fluid phase expelled from the magma. No important economic uranium deposit appears to be mostly related to fractional crystallization of large plutonic bodies

Mining-metallurgical projects for the production of uranium concentrates

International Nuclear Information System (INIS)

Ajuria-Garza, S.

1983-01-01

This report presents an overall view of a complete project for a mining-metallurgical complex for the production of uranium concentrates. Relevant aspects of each important topic are discussed as parts of an integrated methodology. The principal project activities are analyzed and the relationships among the various factors affecting the design are indicated. A list of 96 principal activities is proposed as an example. These activities are distributed in eight groups: initial evaluations preliminary feasibility studies, project engineering, construction, industrial operation, decommissioning and post-decommissioning activities. The environmental impact and the radiological risks due to the construction and operation of the mining metallurgical complex are analyzed. The principles of radiological protection and the regulations, standards and recommendations for radiological protection in uranium mines and mills are discussed. This report is also a guide to the specialized literature: a bibliography with 765 references is included. (author)

Concentration of thorium and uranium in the ecosystem of Atlantic Forest (Mata Atlantica) of Pernambuco state

International Nuclear Information System (INIS)

Ferreira, Fabiano S.; Silva, Waldecy A.; Lira, Marcelo B.G.; Souza, Ebenezer M. de; França, Elvis de

2017-01-01

Thorium (Th) and Uranium (U) are distributed throughout the earth's crust. The mean thorium concentration ranges from 6 to 15 ppm, which makes it 3 times more abundant than uranium. These radionuclides in their natural form, and in low amounts, do not present a risk to the population because they have low activity, but the effects caused by the accumulation in living beings have not yet been fully elucidated. This work aims to evaluate the concentration of Th and U in the soils of an excerpt in the Atlantic Forest in the State of Pernambuco. Soil sampling (depth 0-20 cm) occurred in the projection of tree crowns of the predominant species in the studied areas. After drying and comminution, samples of 0.1 g of soil were submitted to chemical treatment to enable the analysis. This treatment consisted in the addition of 9 ml of HNO 3 (nitric acid) and 3 ml of HF (hydrofluoric acid) with subsequent heating of the sample and reference materials in a digester oven. The concentrations of Th and U were quantified by Inductively Coupled Plasma Mass Spectrometry - ICP-MS. The mean concentrations found were: 10.5 mg kg -1 for thorium and 2.18 mg.kg -1 for uranium, with values of 35 mg.kg -1 and 26 mg.kg -1 quantified in a thorium sample and uranium respectively. In this region, uranium and thorium hotspot were found, which reinforces the need for greater attention to these radionuclides in the Atlantic Forest of the State of Pernambuco

Determination by neutron activation of the uranium-235 concentration in uranium oxides; Determination par activation neutronique de la concentration d'uranium-235 dans des oxydes d'urane

Energy Technology Data Exchange (ETDEWEB)

May, S; Leveque, P [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1959-07-01

Classical methods of measuring isotopic abundance have the disadvantage of being long and of requiring chemical separation. A non-destructive method of measuring the uranium-235 content is described. It is based on an overall measurement of the short lived fission product activity formed during a 15 s neutron irradiation. The precision is of the order {+-} 1.5 per cent for 20 per cent enriched samples. The error due to the contribution from fast fission is discussed in detail. (author) [French] Les methodes classiques de mesure de l'abondance isotopique presentent le gros inconvenient d'etre longues et de necessiter des separations chimiques. Nous exposons une methode non destructive de mesure de la concentration d'uranium-235. Elle est basee sur la mesure globale de l'activite des produits de fission de courte periode formes par une irradiation neutronique de 15 s de l'echantillon. La precision est de l'ordre de {+-} 1,5 pour cent pour des echantillons enrichis jusqu'a 20 pour cent. L'erreur a la contribution de la fission rapide est discutee en detail. (auteur)

Quantification of Kinetic Rate Law Parameters of Uranium Release from Sodium Autunite as a Function of Aqueous Bicarbonate Concentrations

Energy Technology Data Exchange (ETDEWEB)

Gudavalli, Ravi; Katsenovich, Yelena; Wellman, Dawn M.; Lagos, Leonel; Tansel, Berrin

2013-09-05

ABSTRACT: Hydrogen carbonate is one of the most significant components within the uranium geochemical cycle. In aqueous solutions, hydrogen carbonate forms strong complexes with uranium. As such, aqueous bicarbonate may significantly increase the rate of uranium release from uranium minerals. Quantifying the relationship of aqueous hydrogen carbonate solutions to the rate of uranium release during dissolution is critical to understanding the long-term fate of uranium within the environment. Single-pass flow-through (SPTF) experiments were conducted to estimate the rate of uranium release from Na meta-autunite as a function of bicarbonate solutions (0.0005-0.003 M) under the pH range of 6-11 and temperatures of 5-60oC. Consistent with the results of previous investigation, the rate of uranium release from sodium autunite exhibited minimal dependency on temperature; but were strongly dependent on pH and increasing concentrations of bicarbonate solutions. Most notably at pH 7, the rate of uranium release exhibited 370 fold increases relative to the rate of uranium release in the absence of bicarbonate. However, the effect of increasing concentrations of bicarbonate solutions on the release of uranium was significantly less under higher pH conditions. It is postulated that at high pH values, surface sites are saturated with carbonate, thus the addition of more bicarbonate would have less effect on uranium release. Results indicate the activation energies were unaffected by temperature and bicarbonate concentration variations, but were strongly dependent on pH conditions. As pH increased from 6 to 11, activation energy values were observed to decrease from 29.94 kJ mol-1 to 13.07 kJ mol-1. The calculated activation energies suggest a surface controlled dissolution mechanism.

Determination of the uranium concentration in water samples by the technique of fission track recording

International Nuclear Information System (INIS)

Geraldo, L.P.

1979-01-01

The technique of fission track register was developed for the determination of micrograms of uranium. The Makrofol KG, a synthetic plastic made by Bayer, was used as the detector and the wet method was utilized. The detector calibration curve allows the determination of the uranium concentration in a sample within an interval from 8.0 to 0.4μgU/L, the total error ranging from 3.3% to 29.0% respectively. The method was used in the determination of the uranium content in various water samples, obtained from various sources like rivers, sea etc. in the state of Sao Paulo, Brazil. Results were compared with those obtained by other authors using different methods. The average concentration found in sea waters (3.27 +- 9.12μgU/l) by this method is compatible with the international average accepted value of 3.3μgU/l, irrespective of site and depth. The determination of the uranium content by fission track counting has proved to be very convenient. (Author) [pt

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.

Uranium in the shadow of the worldwide nuclear power crisis

International Nuclear Information System (INIS)

Finon, D.

1989-01-01

This paper provides an analysis of the world market for uranium, particularly as it relates to the production of nuclear power. The major characteristics of the uranium market are first described in detail: the geographic concentration of uranium ore and production; the oligopolistic structure of the market; the nature of contracts; the unusual links between buyers and sellers in a large portion of the market created by governmental action; and the role of other political factors. The period of declining average prices and excess capacity that began in 1981 is then discussed and the future of the uranium market is considered. The author shows how the market is evolving into a form somewhat closer to that of markets for other minerals and fuels; henceforth the delivery price of uranium will play a normal role in adjusting supply to the demand conditions that prevail in the uranium market. He also believes that, contrary, the market is not likely to attain an equilibrium before the latter years of the next decade

Determination of Uranium Concentration in Soil of Baghdad Governorate and its Effect on Mitotic Index Assay

International Nuclear Information System (INIS)

Mryoush, A.Q.; Salim, H.M.

2015-01-01

The aim of this work is to determine the uranium concentration in soil samples taken from the north, south, east, west and center of the city of Baghdad and measure its impact on the rate of cell division for non-smokers peoples and living in those areas and that between the ages 25-30 year.The uranium concentration in the samples determined by using CR-39 track detector.As calculated for the ten samples of each site when irradiated by thermal neutrons from the (Am - Be) source with flux (5x 10 3 n S -1 cm -2 ), the concentration values were calculated by a comparison with standard geological samples. The results indicate that the extent of the concentration of uranium in the soil north and east of Baghdad was 12.9 ± 0.7 in Al- Taji north of Baghdad and 12.4 ± 0.23ppm in the Diyala- Bridge area east of Baghdad and the results were recorded lower concentration of uranium in the western, central and southern Baghdad, which stood at 0.60 ± 0.21 in the Abu Ghraib area west of Baghdad, and 4.6 ± 0.7ppm in the Bab-Al-Sharqee of central Baghdad and 0.87 ± 0.7ppm in Al-Mhmodya area south of Baghdad.The mitotic index assay MI in the north and east of Baghdad was 2.3 ± 0.059 in the north and 2.43 ± 0.059 in eastern Baghdad, while the lowest rate in West and Central and South compared with the threshold level of 0.6 . Which indicates contamination north and east of Baghdad as a result of uranium wars on Iraq passed in 2003 which negatively affects the behavior of lymphocytes and on the rate of division

Development of a process to reduce the uranium concentration of liquid radioactive waste

International Nuclear Information System (INIS)

Fuentealba Toro, Edgardo David

2015-01-01

The purpose of radioactive waste management is to prevent the discharge of waste into the biosphere, a function carried out in Chile by the Chilean Nuclear Energy Commission (CCHEN), which stores around 500 [L] of these organic and inorganic waste in cans coming from research of Universities and CCHEN' laboratories. Within the inorganic liquid waste are concentrations of Uranyl salts with sulfates, chlorides and phosphates. The purpose of this work is to develop at laboratory level a process to concentrate and precipitate uranium salts (Sulfate and Uranyl Chloride) present in radioactive liquid effluents, because in the case of these very long period wastes in liquid state, the most widely used processes are aimed at concentrating or extracting radioactive compounds through separation processes, for their conditioning and final storage under conditions whose radiological risk is minimized. The selected process is liquid-liquid extraction, being evaluated solvents such as benzene and kerosene with the following extractants: tri-n-octylphosphine oxide (TOPO), di-2-ethylhexyl phosphoric acid (DEHPA) and Cyanex© 923. To determine the extraction conditions, which allow to reduce the concentration of uranium to values lower than 10 ppm, the extractant concentration was modified from 0.05 to 0.41 [M] with solvent volume / residue (VO/VA) ratios of 0.2 to 0.5, at an initial concentration of 8,446 [gU/L] and subsequent precipitation of uranium extracted by a reaction with ammonium carbonate. From these experimental tests the maximum extraction conditions were determined. To the generated effluents, a second stage of extraction was necessary in order to reduce its concentration below 10 [mg / L]. The experimental tests allowed to reduce the concentration under 2.5 [mgU/L], equivalent to 99.97% extraction efficiency. The tests with Cyanex© 923 in replacement of the TOPO, allowed to obtain similar results and even better in some cases, due to the fact that final

Evaluation the effect of uranium ore concentrations on the cyc2 gene expression in the mutated Acidithiobacillus sp. FJ2

Directory of Open Access Journals (Sweden)

Faezeh Fatemi

2018-06-01

Full Text Available Introduction: The uranium bioleaching process is performed using Acidithiobacillus ferrooxidans. This bacterium is capable of iron oxidation by an electron transport chain. One of the most important components of this chain is the cyc2 gene product that involved in the oxidation process of iron. Materials and methods: Evaluation of UV mutated (60, 120 and 180s Acidithiobacillus sp. FJ2 cyc2gene in the presence of uranium ore concentrations, has been implemented in this project. For this purpose, the original and mutated bacteria were cultivated in the presence of uranium ore concentrations (5, 10, 15, 25 and 50%. Uranium extraction, variation of pH and Eh values were measured at 24 h intervals. Then, when the uranium extraction yield reached to 100%, gene expressions of cyc2 original and mutatedAcidithiobacillus sp. FJ2 were analyzed using Real-time PCR method. Results: The results of the experiments showed that, with increasing pulp density, the uranium extraction rate and oxidation activity of bacteria were reduced. In addition, the result of cyc2 gene expression showed that the target gene expression increases in the presence of uranium ore compared to sample with absence of uranium ore, andwith further increase of pulp density, due to the toxicity of uranium, shows a decreasing trend. Discussion and conclusion: The results of this study indicated that the mutation in the bacterium has a positive effect on the uranium bioleaching process, which can play an important role in the process of uranium bioleaching at high concentrations. In addition, with increasing pulp density due to uranium toxicity, there is a decreasing trend in the process of uranium extraction, which indicates the important role of this factor in the uranium bioleaching process.

Method and apparatus for determining uranium concentration in a moving stream

International Nuclear Information System (INIS)

Bartko, J.; Wonn, J.W.

1977-01-01

The concentration of uranium in a moving stream is determined by agglomerating background microbubbles out of the 6 to 10 micron size range, counting microbubbles in the stream which are about 6 to about 10 microns in size, exposing the stream to a radiation source to cause uranium fission fragments to produce microbubbles, counting microbubbles which are about 6 to about 10 microns in size, and subtracting one count from the other and multiplying by a calibration constant. The subtraction can be performed on an earlier first count so that both counts are made on the same volume. The radiation exposure can be automatically increased when the difference between the first and second counts is low

Concentrations and fluxes of dissolved uranium in the Yellow River estuary: seasonal variation and anthropogenic (Water-Sediment Regulation Scheme) impact

International Nuclear Information System (INIS)

Juanjuan, Sui; Zhigang, Yu; Bochao, Xu; Wenhua, Dong; Dong, Xia; Xueyan, Jiang

2014-01-01

The Water-Sediment Regulation Scheme (WSRS) of the Yellow River is a procedure implemented annually from June to July to expel sediments deposited in Xiaolangdi and other large middle-reach reservoirs and to scour the lower reaches of the river, by controlling water and sediment discharges. Dissolved uranium isotopes were measured in river waters collected monthly as well as daily during the 2010 WSRS (June 19–July 16) from Station Lijin (a hydrologic station nearest to the Yellow River estuary). The monthly samples showed dissolved uranium concentrations of 3.85–7.57 μg l −1 and 234 U/ 238 U activity ratios of 1.24–1.53. The concentrations were much higher than those reported for other global major rivers, and showed seasonal variability. Laboratory simulation experiments showed significant uranium release from bottom and suspended sediment. The uranium concentrations and activity ratios differed during the two stages of the WSRS, which may reflect desorption/dissolution of uranium from suspended river sediments of different origins. An annual flux of dissolved uranium of 1.04 × 10 8 g y −1 was estimated based on the monthly average water discharge and dissolved uranium concentration in the lower reaches of the Yellow River. The amount of dissolved uranium (2.65 × 10 7 g) transported from the Yellow River to the sea during the WSRS constituted about 1/4 of the annual flux. -- Highlights: • Dissolved U in the Yellow River estuary has distinct seasonal variability. • Geochemistry of dissolved U influenced by the WSRS has been analyzed. • Uranium flux during the WSRS has been evaluated

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.

Research on deeply purifying effluent from uranium mining and metallurgy to remove uranium by ion exchange. Pt.2: Elution uranium from lower loaded uranium resin by the intense fractionation process

International Nuclear Information System (INIS)

Zhang Jianguo; Chen Shaoqiang; Qi Jing

2002-01-01

Developing macroporous resin for purifying uranium effluent from uranium mining and metallurgy is presented. The Intense Fractionation Process is employed to elute uranium from lower loaded uranium resin by the eluent of sulfuric acid and ammonium sulfate. The result is indicated that the uranium concentration in the rich elutriant is greatly increased, and the rich liquor is only one bed column volume, uranium concentration in the elutriant is increased two times which concentration is 10.1 g/L. The eluent is saved about 50% compared with the conventional fixed bed elution operation. And also the acidity in the rich elutriant is of benefit to the later precipitation process in uranium recovery

Uranium hydrogeochemical and stream sediment reconnaissance data release for the Leadville NTMS Quadrangle, Colorado, including concentrations of forty-two additional elements

International Nuclear Information System (INIS)

Planner, H.N.

1980-10-01

A total of 1797 locations was sampled over a 19 330-km 2 area, providing an average density of one sample location per 11 km 2 . This report contains results for uranium in water samples and uranium and 42 additional elements in sediment samples. A total of 1279 water samples was collected from streams (1125) and springs (154). Uranium concentrations for all water samples range from below the detection limit of 0.02 ppB to 37.56 ppB. Mean concentrations in streams and springs are 1.05 ppB and 1.19 ppB, respectively. A total of 1784 sediment samples was collected from streams (1590), springs (193), and one pond. Uranium concentrations in sediments range from 1.27 to 223.80 ppM. Statistical mean uranium concentrations for wet stream (8.55 ppM) and spring (7.51 ppM) sediments are found to be greater than their dry counterparts (5.13 ppM and 4.96 ppM, respectively). Field data, recorded at the collection site, are reported with the elemental concentrations for each water and sediment sample listed. These data include a scintillometer determination of the equivalent uranium, pH and conductivity measurements, and geographic and weather information

Concentrations and fluxes of dissolved uranium in the Yellow River estuary: seasonal variation and anthropogenic (Water-Sediment Regulation Scheme) impact.

Science.gov (United States)

Juanjuan, Sui; Zhigang, Yu; Bochao, Xu; Wenhua, Dong; Dong, Xia; Xueyan, Jiang

2014-02-01

The Water-Sediment Regulation Scheme (WSRS) of the Yellow River is a procedure implemented annually from June to July to expel sediments deposited in Xiaolangdi and other large middle-reach reservoirs and to scour the lower reaches of the river, by controlling water and sediment discharges. Dissolved uranium isotopes were measured in river waters collected monthly as well as daily during the 2010 WSRS (June 19-July 16) from Station Lijin (a hydrologic station nearest to the Yellow River estuary). The monthly samples showed dissolved uranium concentrations of 3.85-7.57 μg l(-1) and (234)U/(238)U activity ratios of 1.24-1.53. The concentrations were much higher than those reported for other global major rivers, and showed seasonal variability. Laboratory simulation experiments showed significant uranium release from bottom and suspended sediment. The uranium concentrations and activity ratios differed during the two stages of the WSRS, which may reflect desorption/dissolution of uranium from suspended river sediments of different origins. An annual flux of dissolved uranium of 1.04 × 10(8) g y(-1) was estimated based on the monthly average water discharge and dissolved uranium concentration in the lower reaches of the Yellow River. The amount of dissolved uranium (2.65 × 10(7) g) transported from the Yellow River to the sea during the WSRS constituted about 1/4 of the annual flux. Copyright © 2013 Elsevier Ltd. All rights reserved.

Uranium recovery from slags of metallic uranium

International Nuclear Information System (INIS)

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

2006-01-01

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

Uranium hydrogeochemical and stream sediment reconnaissance of the Arminto NTMS quadrangle, Wyoming, including concentrations of forty-three additional elements

International Nuclear Information System (INIS)

Morgan, T.L.

1979-11-01

During the summers of 1976 and 1977, 570 water and 1249 sediment samples were collected from 1517 locations within the 18,000-km 2 area of the Arminto NTMS quadrangle of central Wyoming. Water samples were collected from wells, springs, streams, and artifical ponds; sediment samples were collected from wet and dry streams, springs, and wet and dry ponds. All water samples were analyzed for 13 elements, including uranium, and each sediment sample was analyzed for 43 elements, including uranium and thorium. Uranium concentrations in water samples range from below the detection limit to 84.60 parts per billion (ppb) with a mean of 4.32 ppb. All water sample types except pond water samples were considered as a single population in interpreting the data. Pond water samples were excluded due to possible concentration of uranium by evaporation. Most of the water samples containing greater than 20 ppb uranium grouped into six clusters that indicate possible areas of interest for further investigation. One cluster is associated with the Pumpkin Buttes District, and two others are near the Kaycee and Mayoworth areas of uranium mineralization. The largest cluster is located on the west side of the Powder River Basin. One cluster is located in the central Big Horn Basin and another is in the Wind River Basin; both are in areas underlain by favorable host units. Uranium concentrations in sediment samples range from 0.08 parts per million (ppm) to 115.50 ppm with a mean of 3.50 ppm. Two clusters of sediment samples over 7 ppm were delineated. The first, containing the two highest-concentration samples, corresponds with the Copper Mountain District. Many of the high uranium concentrations in samples in this cluster may be due to contamination from mining or prospecting activity upstream from the sample sites. The second cluster encompasses a wide area in the Wind River Basin along the southern boundary of the quadrangle

Uranium hydrogeochemical and stream sediment reconnaissance of the Arminto NTMS quadrangle, Wyoming, including concentrations of forty-three additional elements

Energy Technology Data Exchange (ETDEWEB)

Morgan, T.L.

1979-11-01

During the summers of 1976 and 1977, 570 water and 1249 sediment samples were collected from 1517 locations within the 18,000-km/sup 2/ area of the Arminto NTMS quadrangle of central Wyoming. Water samples were collected from wells, springs, streams, and artifical ponds; sediment samples were collected from wet and dry streams, springs, and wet and dry ponds. All water samples were analyzed for 13 elements, including uranium, and each sediment sample was analyzed for 43 elements, including uranium and thorium. Uranium concentrations in water samples range from below the detection limit to 84.60 parts per billion (ppb) with a mean of 4.32 ppb. All water sample types except pond water samples were considered as a single population in interpreting the data. Pond water samples were excluded due to possible concentration of uranium by evaporation. Most of the water samples containing greater than 20 ppb uranium grouped into six clusters that indicate possible areas of interest for further investigation. One cluster is associated with the Pumpkin Buttes District, and two others are near the Kaycee and Mayoworth areas of uranium mineralization. The largest cluster is located on the west side of the Powder River Basin. One cluster is located in the central Big Horn Basin and another is in the Wind River Basin; both are in areas underlain by favorable host units. Uranium concentrations in sediment samples range from 0.08 parts per million (ppm) to 115.50 ppm with a mean of 3.50 ppm. Two clusters of sediment samples over 7 ppm were delineated. The first, containing the two highest-concentration samples, corresponds with the Copper Mountain District. Many of the high uranium concentrations in samples in this cluster may be due to contamination from mining or prospecting activity upstream from the sample sites. The second cluster encompasses a wide area in the Wind River Basin along the southern boundary of the quadrangle.

Marine mollusks as bio concentrators of uranium and plutonium

International Nuclear Information System (INIS)

Ordonez R, E.; Almazan T, M. G.; Escalante G, D. C.

2017-09-01

The sudden presence of certain radionuclides in the marine environment has been of global concern and has raised concerns about the nature and abundance of these, in an attempt to establish dispersion patterns from their discharge points. In the particular case of our country, there are few data on the presence and concentration of alpha emitters, such as uranium and plutonium in the littorals and due to this fact there is a need to establish their reference levels in some specific points of the Mexican littoral. This work thus raises the study of part of the biota that grows and develops in sites near the sampling points. Is known that bivalve mollusks are natural bio-concentrators due to their capacity to absorb some metals dissolved in water, being able to find contaminating metals in their soft bodies, but they also accumulate large quantities when they generate their shells from dissolved carbonates that are complex with uranium and plutonium. The shells of the mollusks were studied to determine the physicochemical characteristics of their shells and the U and Pu were also separated by means of radiochemical techniques, being then electrodeposited in steel discs and evaluated by means of alpha spectroscopy. The results of the methodology prototype are presented to determine the U and Pu dispersed in the littoral by means of the analysis of some mollusks of the zone. (Author)

Ore-concentrating structures with telescoped uranium mineralization

International Nuclear Information System (INIS)

Shchetochkin, V.N.; Dmitriyev, V.I.; Tkachenko, I.I.

1986-01-01

Deep faults are the main controlling elements in uranium ore fields, although the immediate geologic environments may be quite varied. Within the fault zones, the uranium fields are usually associated with areas where major transverse and diagonal faults intersect or link, and with points of splitting or change in strike in disjunctive zones. Another distinctive feature of the mineralized structure is their long history, with a combination of tectonic elements differing in age and type, usually associated with retrograde dislocation metamorphism. The specific features of these structures control the uranium mineralization, which is usually localized in foci with telescoped tectonic, magmatic, hydrothermal, metasomatic, and sometimes exogenous processes. The unnamed area (in the Ukraine?) furnishes a good example of how successive stages of a complex geologic history affect the occurrence of such a highly mobile element as uranium. 12 references, 4 figures

Uranium geochemistry of Orca Basin

International Nuclear Information System (INIS)

Weber, F.F. Jr.; Sackett, W.M.

1981-01-01

Orca Basin, an anoxic, brine-filled depression at a depth of 2200 m in the Northwestern Gulf of Mexico continental slope, has been studied with respect to its uranium geochemistry. Uranium concentration profiles for four cores from within the basin were determined by delayed-neutron counting. Uranium concentrations ranged from 2.1 to 4.1 ppm on a salt-free and carbonate-corrected basis. The highest uranium concentrations were associated with the lowest percentage and delta 13 C organic carbon values. For comparison, cores from the brine-filled Suakin and Atlantis II Deeps, both in the Red Sea, were also analyzed. Uranium concentrations ranged from 1.2 to 2.6 ppm in the Suakin Deep and from 8.0 to 11.0 ppm in the Atlantis II Deep. No significant correlation was found between uranium concentrations and organic carbon concentrations and delta 13 C values for these cores. Although anoxic conditions are necessary for significant uranium uptake by non-carbonate marine sediments, other factors such as dilution by rapidly depositing materials and uranium supply via mixing and diffusion across density gradients may be as important in determining uranium concentrations in hypersaline basin sediments. (author)

Simple, cost effective method for determination of phosphorus in uranium ore concentrate

International Nuclear Information System (INIS)

Misra, U.B.; Ramamurty, Vasantha; Dutta, M.; Balaji Rao, Y.; Subba Rao, Y.

2015-01-01

In this paper determination of phosphate as phosphorus in uranium ore concentrate has been described. The method used is spectrophotometric determination of phosphorus as phospho-molybdenum blue complex. As uranyl ion do not absorb in 600-900 nm range of visible region in the present medium, the phosphomolybdenum blue complex formation which is having maximum absorbance at 825 nm is exploited for determination of phosphorus. The molar absorptivity coefficient with and without the presence of uranium matrix are 2.6048 x 10 4 and 2.6730 x 10 4 lmol -1 cm -1 . The effect of matrix is not evident from the experiment carried out. (author)

Measurement of uranium concentration by molecular absorption spectrophotometry by means optical fibers

International Nuclear Information System (INIS)

Gauna, Alberto C.; Pascale, Ariel A.

1996-01-01

An on-line method for measuring the concentration of uranium in uranyl nitrate-nitric acid aqueous solutions is described. The method is based on molecular absorption spectrophotometry with transmission of light by means of optical fibers. It is ideally suited for control and processes development applications. (author)

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

International Nuclear Information System (INIS)

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

1995-11-01

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

Decommissioning of U.S. uranium production facilities

Energy Technology Data Exchange (ETDEWEB)

1995-02-01

From 1980 to 1993, the domestic production of uranium declined from almost 44 million pounds U{sub 3}O{sub 8} to about 3 million pounds. This retrenchment of the U.S. uranium industry resulted in the permanent closing of many uranium-producing facilities. Current low uranium prices, excess world supply, and low expectations for future uranium demand indicate that it is unlikely existing plants will be reopened. Because of this situation, these facilities eventually will have to be decommissioned. The Uranium Mill Tailings and Radiation Control Act of 1978 (UMTRCA) vests the U.S. Environmental Protection Agency (EPA) with overall responsibility for establishing environmental standards for decommissioning of uranium production facilities. UMTRCA also gave the U.S. Nuclear Regulatory Commission (NRC) the responsibility for licensing and regulating uranium production and related activities, including decommissioning. Because there are many issues associated with decommissioning-environmental, political, and financial-this report will concentrate on the answers to three questions: (1) What is required? (2) How is the process implemented? (3) What are the costs? Regulatory control is exercised principally through the NRC licensing process. Before receiving a license to construct and operate an uranium producing facility, the applicant is required to present a decommissioning plan to the NRC. Once the plan is approved, the licensee must post a surety to guarantee that funds will be available to execute the plan and reclaim the site. This report by the Energy Information Administration (EIA) represents the most comprehensive study on this topic by analyzing data on 33 (out of 43) uranium production facilities located in Colorado, Nebraska, New Mexico, South Dakota, Texas, Utah, and Washington.

Decommissioning of U.S. uranium production facilities

International Nuclear Information System (INIS)

1995-02-01

From 1980 to 1993, the domestic production of uranium declined from almost 44 million pounds U 3 O 8 to about 3 million pounds. This retrenchment of the U.S. uranium industry resulted in the permanent closing of many uranium-producing facilities. Current low uranium prices, excess world supply, and low expectations for future uranium demand indicate that it is unlikely existing plants will be reopened. Because of this situation, these facilities eventually will have to be decommissioned. The Uranium Mill Tailings and Radiation Control Act of 1978 (UMTRCA) vests the U.S. Environmental Protection Agency (EPA) with overall responsibility for establishing environmental standards for decommissioning of uranium production facilities. UMTRCA also gave the U.S. Nuclear Regulatory Commission (NRC) the responsibility for licensing and regulating uranium production and related activities, including decommissioning. Because there are many issues associated with decommissioning-environmental, political, and financial-this report will concentrate on the answers to three questions: (1) What is required? (2) How is the process implemented? (3) What are the costs? Regulatory control is exercised principally through the NRC licensing process. Before receiving a license to construct and operate an uranium producing facility, the applicant is required to present a decommissioning plan to the NRC. Once the plan is approved, the licensee must post a surety to guarantee that funds will be available to execute the plan and reclaim the site. This report by the Energy Information Administration (EIA) represents the most comprehensive study on this topic by analyzing data on 33 (out of 43) uranium production facilities located in Colorado, Nebraska, New Mexico, South Dakota, Texas, Utah, and Washington

Mineralogical characterization of uranium yellow cake concentrates

International Nuclear Information System (INIS)

Hausen, D.M.

1992-01-01

Uranium yellow cake concentrates have been analyzed and characterized mineralogically by means of differential thermal analysis, X-ray diffraction, infrared spectra and wet chemical methods. On the basis of mineralogical methods of characterization, the following four major structural types of yellow cake may be classified: Uranyl Hydroxide Hydrate, UO 2 (OH) 2 nH 2 O; Basic Uranyl Sulfate Hydrate, (UO 2 ) x (SO 4 ) y (OH) s(x-y ).nH 2 O; Sodium Para-Uranate, Na 5 U 7 O 24 and Uranyl Peroxide Hydrate, UO 4 .nH 2 O. In this paper conditions of yellow cake preparation and characterization are described, along with discussion of significance of structural types to the physical and chemical properties of yellow cake production

Comparison of neutron activation analysis techniques for the determination of uranium concentrations in geological and environmental materials

International Nuclear Information System (INIS)

Landsberger, S.; Kapsimalis, R.

2013-01-01

We have described the determination of uranium in environmental, geological, and agricultural specimens by three different non-destructive nuclear methods. The effectiveness, as defined as the lower limits of detection in this work, of quantifying trace levels of bulk uranium in geological samples was evaluated for several common NAA techniques. These techniques include short-lived and medium-lived neutron activation analysis using thermal and epithermal neutrons; these results were compared with an assessment of Compton suppressed gamma-ray counting. A careful evaluation of three major (n,γ) reactions with chlorine, manganese and sodium that could impede determining low levels of uranium due to high Compton continuums was done. The evaluation of Compton suppressed passive gamma counting revealed that uranium concentrations below 50 mg kg −1 were not adequate to achieve good counting statistics using the 234m Pa the second daughter product of 238 U. -- Highlights: ► Determination of uranium concentrations in geological, environmental, and agricultural specimens. ► Use of several NAA and passive counting methods. ► Identified several key interferences. ► Use of Compton suppression to minimize effects of interferences

Uranium hydrogeochemical and stream sediment reconnaissance data release for the Butte NTMS Quadrangle, Montana, including concentrations of forty-two additional elements

International Nuclear Information System (INIS)

Broxton, D.E.; George, W.E.; Montoya, J.V.; Martell, C.J.; Hensley, W.K.; Hanks, D.

1980-05-01

This report contains data collected during a geochemical survey for uranium in the Butte National Topographic Map Series (NTMS) quadrangle of west-central Montana. Histograms and statistical data for uranium concentrations in water and sediment samples and thorium concentrations in sediment samples are given. Elemental concentration, field measurement, weather, geologic, and geographic data for each sample location are listed for waters and for sediments. Uranium/thorium ratios for sediment samples are also included. This report contains uranium analyses for water samples and multielement analyses for sediment samples. A supplemental report containing the results of multielement analyses of water samples will be open filed in the near future. Sediments were analyzed for uranium and thorium as well as aluminum, antimony, barium, beryllium, bismuth, cadmium, calcium, cerium, cesium, chlorine, chromium, cobalt, copper, dysprosium, europium, gold, hafnium, iron, lanthanum, lead, lithium, lutetium, magnesium, manganese, nickel, niobium, potassium, rubidium, samarium, scandium, silver, sodium, strontium, tantalum, terbium, tin, titanium, tungsten, vanadium, ytterbium, and zinc. All elemental analyses were performed at the LASL. Water samples were initially analyzed for uranium by fluorometry. All water samples containing more than 40 ppB uranium were reanalyzed by delayed-neutron counting (DNC). All sediments were analyzed for uranium by DNC. Other elemental concentrations in sediments were determined by neutron activation analysis for 31 elements, by x-ray fluorescence for 9 elements, and by arc-source emission spectrography for 2 elements. Analytical results for sediments are reported as parts per million. Descriptions of procedures used for analysis of water and sediment samples as well as analytical precisions and detection limits are given

Uranium concentrations in lake and stream waters and sediments from selected sites in the Susitna River Basin, Alaska

International Nuclear Information System (INIS)

Hill, D.E.

1977-03-01

During the summer of 1976, 141 water and 211 sediment samples were taken from 147 locations in the Susitna River basin in Alaska by the Geophysical Institute of the University of Alaska for the LASL. These samples were taken to provide preliminary information on the uranium concentrations in waters and sediments from the Susitna River basin and to test the analytical methods proposed for the NURE Hydrogeochemical and Stream Sediment Reconnaissance for uranium in Alaska. The uranium determinations resulting from the fluorometric analysis of the water samples and the delayed-neutron counting of the sediment samples are presented. The low levels of uranium in the water samples, many of which were below the detectable limit of the LASL fluorometric technique, indicate that a more sensitive analytical method is needed for the analysis of Alaskan water samples from this area. An overlay showing numbered sample locations and overlays graphically portraying the concentrations of uranium in the water and sediment samples, all at 1:250,000 scale for use with existing USGS topographic sheets, are also provided as plates

An Overview of Process Monitoring Related to the Production of Uranium Ore Concentrate

Energy Technology Data Exchange (ETDEWEB)

McGinnis, Brent [Innovative Solutions Unlimited, LLC

2014-04-01

Uranium ore concentrate (UOC) in various chemical forms, is a high-value commodity in the commercial nuclear market, is a potential target for illicit acquisition, by both State and non-State actors. With the global expansion of uranium production capacity, control of UOC is emerging as a potentially weak link in the nuclear supply chain. Its protection, control and management thus pose a key challenge for the international community, including States, regulatory authorities and industry. This report evaluates current process monitoring practice and makes recommendations for utilization of existing or new techniques for managing the inventory and tracking this material.

Measurements of radon daughter concentrations in structures built on or near uranium mine tailings

International Nuclear Information System (INIS)

Haywood, F.F.; Kerr, G.D.; Goldsmith, W.A.; Perdue, P.T.; Thorngate, J.H.

1976-01-01

A technique is discussed that has been used to measure air concentrations of short-lived daughters of 222 Rn in residential and commercial structures built on or near uranium mill tailings in the western part of the United States. In this technique, the concentrations of RaA, RaB, and RaC are calculated from one integral count of the RaA and two integral counts of the RaC' alpha-particle activity collected on a filter with an air sampling device. A computer program is available to calculate the concentrations of RaA, RaB, and RaC in air and to estimate the accuracy in these calculated concentrations. This program is written in the BASIC language. Also discussed in this paper are the alpha-particle spectrometer used to count activity on the air filters and the results of our radon daughter measurements in Colorado, Utah, and New Mexico. These results and results of other measurements discussed in a companion paper are now being used in a comprehensive study of potential radiation exposures to the public from uranium mill tailing piles

Uranium 2007 resources, production and demand

CERN Document Server

Organisation for Economic Cooperation and Development. Paris

2008-01-01

Based on official information received from 40 countries, Uranium 2007 provides a comprehensive review of world uranium supply and demand as of 1st January 2007, as well as data on global uranium exploration, resources, production and reactor-related requirements. It provides substantive new information from 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 2030 are also featured, along with an analysis of long-term uranium supply and demand issues. It finds that with rising demand and declining inventories, uranium prices have increased dramatically in recent years. As a result, the uranium industry is undergoing a significant revival, bringing to an end a period of over 20 years of underinvestment.

Analysis of queuing mine-cars affecting shaft station radon concentrations in Quzhou uranium mine, eastern China

Directory of Open Access Journals (Sweden)

Changshou Hong

2018-04-01

Full Text Available Shaft stations of underground uranium mines in China are not only utilized as waiting space for loaded mine-cars queuing to be hoisted but also as the principal channel for fresh air taken to working places. Therefore, assessment of how mine-car queuing processes affect shaft station radon concentration was carried out. Queuing network of mine-cars has been analyzed in an underground uranium mine, located in Quzhou, Zhejiang province of Eastern China. On the basis of mathematical analysis of the queue network, a MATLAB-based quasi-random number generating program utilizing Monte-Carlo methods was worked out. Extensive simulations were then implemented via MATALB operating on a DELL PC. Thereafter, theoretical calculations and field measurements of shaft station radon concentrations for several working conditions were performed. The queuing performance measures of interest, like average queuing length and waiting time, were found to be significantly affected by the utilization rate (positively correlated. However, even with respect to the “worst case”, the shaft station radon concentration was always lower than 200 Bq/m3. The model predictions were compared with the measuring results, and a satisfactory agreement was noted. Under current working conditions, queuing-induced variations of shaft station radon concentration of the study mine are not remarkable. Keywords: Hoist and Transport Systems, Mine-cars, Queuing Simulation, Radon Concentration, Underground Uranium Mine

Uranium hydrogeochemical and stream sediment reconnaissance data release for the Socorro NRMS Quadrangle, New Mexico, including concentrations of forty-two additional elements

International Nuclear Information System (INIS)

Planner, H.N.; Fuka, M.A.; Hanks, D.E.; Hansel, J.M.; Minor, M.M.; Montoya, J.D.; Sandoval, W.F.

1980-10-01

Results for uranium in water samples and uranium and 42 additional elements in sediment samples are given. A total of 650 water samples was collected from wells (525), springs (99), streams (25), and one pond. Uranium concentrations for all water samples range from below the detection limit to 157.20 parts per billion (ppB). Mean concentrations in springs and well waters are 4.91 ppB and 5.04 ppB, respectively, compared to a value of 2.78 ppB in stream waters. Of the 1384 sediment samples collected, 1246 are from dry stream beds. The remaining 138 samples are from springs (68), ponds (50), and flowing streams (20). Uranium concentrations in sediments range from 0.84 to 13.40 parts per million (ppM) with the exception of a single 445.10-ppM concentration. The mean uranium content of all sediments is 3.12 ppM. Field data, recorded at the collection site, are reported with the elemental concentrations for each water and sediment sample listed in Appendixes I-A and I-B. These data include a scintillometer determination of the equivalent uranium, pH and conductivity measurements, and geographic and weather information. Appendix II explains the codes used in Appendix I and describes the standard field and analytical procedures used by the LASL in the HSSR program

Calculation of depleted uranium concentration in dental fillings samples using the nuclear track detector CR-39

International Nuclear Information System (INIS)

Mahdi, K. H.; Subhi, A. T.; Tawfiq, N. F.

2012-12-01

The purpose of this study is to determine the concentration of depleted uranium in dental fillings samples, which were obtained some hospital and dental office, sale of materials deployed in Iraq. 8 samples were examined from two different fillings and lead-filling (amalgam) and composite filling (plastic). concentrations of depleted uranium were determined in these samples using a nuclear track detector CR-39 through the recording of the tracks left by of fragments of fission resulting from the reaction 2 38U (n, f). The samples are bombarded by neutrons emitted from the neutron source (2 41A m-Be) with flux of ( 10 5 n. cm- 2. s -1 ). The period of etching to show the track of fission fragments is 5 hours using NaOH solution with normalization (6.25N), and temperature (60 o C ). Concentration of depleted uranium were calculated by comparison with standard samples. The result that obtained showed that the value of the weighted average for concentration of uranium in the samples fillings (5.54± 1.05) ppm lead to thr filling (amalgam) and (5.33±0.6) ppm of the filling composite (plastic). The hazard- index, the absorbed dose and the effective dose for these concentration were determined. The obtained results of the effective dose for each of the surface of the bone and skin (as the areas most affected by this compensation industrial) is (0.56 mSv / y) for the batting lead (amalgam) and (0.54 mSv / y) for the filling composite (plastic). From the results of study it was that the highest rate is the effective dose to a specimen amalgam filling (0.68 mSv / y) which is less than the allowable limit for exposure of the general people set the World Health Organization (WHO), a (1 mSv / y). (Author)

Investigation of spectral interference effects on determination of uranium concentration in phosphate ore by inductively coupled plasma optical emission spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Bachari, Ayoob H.; Jalali, Fatemeh; Alahyarizadeh, Ghasem [Tehran Univ. (Iran, Islamic Republic of). Engineering Dept.

2017-04-01

Effects of spectral interferences on determination of the uranium concentration in phosphate ore were investigated by inductively coupled plasma optical emission spectroscopy (ICP-OES). Eleven high intensity emission lines including four lines recommended by ICP-OES apparatus were chosen to determine the uranium concentration. The ore samples were collected from phosphate acid producing industry in the south of Iran. Three different acid combinations [(HNO{sub 3}:HCl:HF-2:6:2), (H{sub 3}PO{sub 4}:H{sub 2}SO{sub 4}:HF-3:3:3), (HNO{sub 3}:H{sub 2}O{sub 2}:HF-4:2:2)] used in microwave digestion method to explore the spectral interference effects in different solvent environments. The results showed that the trusty uranium concentration, obtained in the 367.007 nm, 386.592 nm, 389.036 nm and 409.014 nm by second acid digestion method which were 0.665 ppm, 0.972 ppm, 0.670 ppm and 0.801 ppm, respectively. Although the line of 409.014 nm was reported as the best line for determining of the uranium concentration in several literatures, the results showed that this line has a significant spectral interference with vanadium in some ores which should be considered in determining of the uranium concentration. Spectral interference effects of some elements which have high concentrations in the phosphate ore including Ca, Fe, Mg, Pb, V, Mn, and Ti on the line intensities were also investigated. Results indicated that the chosen elements affect emission intensities of all of 11 lines. They also indicated that the line of 409.014 nm provides a trusty precision in the determination of the uranium concentration in the ore sample with low vanadium concentration (at least, U/V ratio of 1:5). Results show that the line of 409.014 nm provides acceptable precision with some corrections in comparison with other selected lines. For instance in high concentrations of other elements including Fe and Ti in the ore samples, strong influences on the line intensities of the 367.007 nm (by Fe

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

Distribution of indoor radon concentrations and uranium-bearing rocks in Texas

International Nuclear Information System (INIS)

Hudak, P.F.

1996-01-01

The purpose of this study was to compare regional patterns of indoor radon concentration with uranium-bearing rock zones and county populations in Texas. Zones yielding radon concentrations that are relatively high for Texas include shale and sandstone in northwest Texas; red beds in north-central Texas; felsic volcanic rocks in west Texas; and sandstone, limestone, and igneous rocks in central Texas. Located in northwest Tecas, only five of the 202 counties evaluated have mean indoor radon concentrations above 4.0 pCi l -1 . Two of those counties have populations above the state median of 20115. The highest county mean concentration is 8.8 pCi l -1 . Results of the study suggest that (1) regional geology influences indoor radon concentrations in Texas, (2) statewide, the radon concentrations are relatively low, (3) highly populated counties do not coincide with regions of high indoor radon concentration, and (4) regions that may warrant further monitoring include northwest Texas and, to a lesser degree, west and central Texas. (orig.)

Influence of season growth, soils and irrigation water composition on the concentration of uranium in two lettuce (Lactuca sativa L.) varieties. Field experiments

Science.gov (United States)

Abreu, M. M.; Neves, O.; Marcelino, M.

2012-04-01

Former uranium mines areas are frequently the sources of environmental radionuclides problems even many years after the closure of mining operations. A concern for inhabitants from mining areas is the use of contaminated land or irrigation water for agriculture, and the potential transfer of metals from soils to vegetables, and to humans through the food chain. The main aim of this study was to compare the uranium concentration in lettuce (Lactuca sativa L. varieties Marady and Romana) grown in different seasons (autumn and summer) and exposed to high and low uranium concentrations both in irrigation water and agricultural soil. The content of uranium in irrigation water, soil (total and available fraction) and in lettuce leaf samples was analyzed in a certified laboratory. In the field experiments, two agricultural soils were divided into two plots (four replicates each); one of them was irrigated with uranium contaminated water (0.94 to 1.14 mg/L) and the other with uncontaminated water (< 0.02 mg/L). Irrigation with contaminated water together with highest soil uranium available concentration (10 to 13 mg/kg) had negative effects on both studied lettuce varieties, namely yield reduction (up to 53% and 87% in autumn and summer experiments, respectively) and increase of uranium leaf concentration (up to 1.4 and 7 fold in autumn and summer, respectively). Effect on lettuce yield was mainly due to the high soil salinity (1.01 to 6.31 mS/cm) as a consequence of high irrigation water electrical conductivity (up to 1.82 mS/cm) and low lettuce soil salinity tolerance (1 to 3 mS/cm). The highest lettuce uranium concentration (dry weight) observed was 2.13 and 5.37 mg/kg for Marady and Romana variety, respectively. The highest uranium lettuce concentration in Romana variety was also the effect of its growing in summer season when it was subject to greatest frequency and amount of water irrigation. The consumption by an adult of the lettuce that concentrate more uranium

Analysis methods and performance of an automated system for measuring both concentration and enrichment of uranium in solutions

International Nuclear Information System (INIS)

Kelley, T.A.; Parker, J.L.; Sampson, T.E.

1993-01-01

For the 1992 INNM meeting, the authors reported on the general characteristics of an automated system--then under development--for measuring both the concentration and enrichment of uranium in solutions. That paper emphasized the automated control capability, the measurement sequences, and safety features of the system. In this paper, the authors report in detail on the measurement methods, the analysis algorithms, and the performance of the delivered system. The uranium concentration is measured by a transmission-corrected X-ray fluorescence method. Cobalt-57 is the fluorescing source and a combined 153 Gd and 57 Co source is used for the transmission measurements. Corrections are made for both the absorption of the exciting 57 Co gamma rays and the excited uranium X-rays. The 235 U concentration is measured by a transmission-corrected method, which employs the 185.7-keV gamma ray of 235 U and a transmission source of 75 Se to make corrections for the self-absorption of the 235 U gamma rays in the solution samples. Both measurements employ high-resolution gamma-ray spectrometry and use the same 50ml sample contained in a custom-molded, flat-bottomed, polypropylene bottle. Both measurements are intended for uranium solutions with concentrations ≥0.1 g U/l, although at higher enrichments the passive measurement will be even more sensitive

Past and future of uranium production

International Nuclear Information System (INIS)

Max, A.; Mason, T.

1996-01-01

Changes in world politics over the last few years have directly affected supplies and price levels in the front-end nuclear industry. Limited by the advance of CIS and East European uranium and nuclear fuel services into the west, the trend towards a declining uranium industry continued until 1994. The expected introduction of military uranium from Russian and American warheads into the civil nuclear fuel cycle creates additional unknowns in the nuclear fuel market. However, the long lasting recession in the uranium industry may already be coming to an end: The uranium inventories still in existence and uranium from the conversion of nuclear warheads will not last long enough to close the existing gap between uranium demand and supply. Additional uranium production will be required as a result. (orig.) [de

Domestic uranium mining and milling

International Nuclear Information System (INIS)

Anon.

1983-01-01

A field hearing was held in Riverton, Wyoming on the erosion of the state's uranium industry as production and capital investment have declined and inventories have continued to rise because of a shift to foreign suppliers. The result has been serious unemployment in Wyoming and a decline in uranium mines from 5400 in 1980 to the present 1200. The seven witnesses spoke for the mining industry and state and federal government. Among the issues raised were mining regulations and the cancellation of nuclear rejects which have impacted the health of the industry. Additional statements and a report supplied for the record follow their testimony

Effect of depositional environment and sources of pollution on uranium concentration in sediment, coral, algae and seagrass species from the Gulf of Aqaba (Red Sea)

International Nuclear Information System (INIS)

Abu-Hilal, A.H.

1994-01-01

Uranium concentrations were determined in sediment samples, four hard and two soft corals, one seagrass and four species of algae collected from phosphate-polluted sites in the northern reef area of the Gulf of Aqaba. High uranium concentrations were found in all samples examined from a phosphate-polluted site near a phosphate loading berth compared to the unpolluted ones. Uranium levels, U/Ca ratios, concentration and discrimination factors were also high compared to those reported from other regions of the world. The effects of the exported raw phosphate powder as the main source of pollution and depositional environment on the concentration of uranium in the examined species are discussed. (Author)

Uranium luminescence in La2 Zr2 O7 : effect of concentration and annealing temperature.

Science.gov (United States)

Mohapatra, M; Rajeswari, B; Hon, N S; Kadam, R M

2016-12-01

The speciation of a particular element in any given matrix is a prerequisite to understanding its solubility and leaching properties. In this context, speciation of uranium in lanthanum zirconate pyrochlore (La 2 Zr 2 O 7  = LZO), prepared by a low-temperature combustion route, was carried out using a simple photoluminescence lifetime technique. The LZO matrix is considered to be a potential ceramic host for fixing nuclear and actinide waste products generated during the nuclear fuel cycle. Special emphasis has been given to understanding the dynamics of the uranium species in the host as a function of annealing temperature and concentration. It was found that, in the LZO host, uranium is stabilized as the commonly encountered uranyl species (UO 2 2+ ) up to a heat treatment of 500 °C at the surface. Above 500 °C, the uranyl ion is diffused into the matrix as the more symmetric octahedral uranate species (UO 6 6- ). The uranate ions thus formed replace the six-coordinated 'Zr' atoms at regular lattice positions. Further, it was observed that concentration quenching takes place beyond 5 mol% of uranium doping. The mechanism of the quenching was found to be a multipolar interaction. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Response of plants to high concentrations of uranium stress and the screening of remediation plants

International Nuclear Information System (INIS)

Tang Yongjin; Luo Xuegang; Zeng Feng; Jiang Shijie

2013-01-01

Studies of the resistance and accumulation ability of different plant species to uranium (U) has important influence on the bioremediation of U contaminated soil. The resistance and enrichment ability of high concentrations of U (500 mg · kg"-"1 soil) in fourteen plant species were investigated and evaluated in this study in order to screen remediation plants for governance soil U contamination. The results showed that: (1) high concentrations of U stress had different effects on the emergence and survival of the different plants. The seed emergence of Hibiscus esculentus was reduced by 2/3, but the seed emergence of Gynura cusimbua (D. Don) S. Moore, Chenopodium album L. and Phaseolus vulgaris var. humilis Alef were not reduced. Under the contaminated soil, all the sesamum indicum died within a month after the emergence and the survival number of Amaranth and Iresine herbstii 'Aureo-reticulata' reduced by about 80%. But the survival number of Alternanthera philoxeroides (Mart.) Griseb., Chenopodium album L. and Phaseolus vulgaris var. humilis Alef were not influenced. (2) The biomass of the plants would be reduced by 8-99% in the uranium-contaminated soil. The anti-stress ability of Phaseolus vulgaris var. humilis Alef was the strongest in the fourteen plants, and Cucurbita pepo L., Sorghumbicolor (L.) Moench, Ipomoea aquatica Forsk, Helianthus annuus, Chenopodium album L. and Alternanthera philoxeroides (Mart.) Griseb. showed some the anti-stress ability. (3) Significant differences were found in the capacity of plants to absorb uranium between under high-uranium contaminated soil and under the non-uranium contaminated soil were. The plants with higher uranium content in thenon-contaminated soil were Gomphrena globosa, and Cucurbita pepo L., which were 2.249 mg · kg"-"1 DW and 1.620 mg · kg"-"1 DW, respectively. But the plants with higher uranium content in the high uranium contaminated soil were Cichorium intybus L., Amaranth and Ipomoea aquatica Forsk, which

Diffusive gradient in thin FILMS (DGT) compared with soil solution and labile uranium fraction for predicting uranium bioavailability to ryegrass.

Science.gov (United States)

Duquène, L; Vandenhove, H; Tack, F; Van Hees, M; Wannijn, J

2010-02-01

The usefulness of uranium concentration in soil solution or recovered by selective extraction as unequivocal bioavailability indices for uranium uptake by plants is still unclear. The aim of the present study was to test if the uranium concentration measured by the diffusive gradient in thin films (DGT) technique is a relevant substitute for plant uranium availability in comparison to uranium concentration in the soil solution or uranium recovered by ammonium acetate. Ryegrass (Lolium perenne L. var. Melvina) is grown in greenhouse on a range of uranium spiked soils. The DGT-recovered uranium concentration (C(DGT)) was correlated with uranium concentration in the soil solution or with uranium recovered by ammonium acetate extraction. Plant uptake was better predicted by the summed soil solution concentrations of UO(2)(2+), uranyl carbonate complexes and UO(2)PO(4)(-). The DGT technique did not provide significant advantages over conventional methods to predict uranium uptake by plants. Copyright 2009 Elsevier Ltd. All rights reserved.

Diffusive gradient in thin FILMS (DGT) compared with soil solution and labile uranium fraction for predicting uranium bioavailability to ryegrass

Energy Technology Data Exchange (ETDEWEB)

Duquene, L. [SCK-CEN, Biosphere Impact Studies, Boeretang 200, B-2400 Mol (Belgium); Vandenhove, H., E-mail: hvandenh@sckcen.b [SCK-CEN, Biosphere Impact Studies, Boeretang 200, B-2400 Mol (Belgium); Tack, F. [Ghent University, Laboratory for Analytical Chemistry and Applied Ecochemistry, Coupure Links 653, B-9000 Gent (Belgium); Van Hees, M.; Wannijn, J. [SCK-CEN, Biosphere Impact Studies, Boeretang 200, B-2400 Mol (Belgium)

2010-02-15

The usefulness of uranium concentration in soil solution or recovered by selective extraction as unequivocal bioavailability indices for uranium uptake by plants is still unclear. The aim of the present study was to test if the uranium concentration measured by the diffusive gradient in thin films (DGT) technique is a relevant substitute for plant uranium availability in comparison to uranium concentration in the soil solution or uranium recovered by ammonium acetate. Ryegrass (Lolium perenne L. var. Melvina) is grown in greenhouse on a range of uranium spiked soils. The DGT-recovered uranium concentration (C{sub DGT}) was correlated with uranium concentration in the soil solution or with uranium recovered by ammonium acetate extraction. Plant uptake was better predicted by the summed soil solution concentrations of UO{sub 2}{sup 2+}, uranyl carbonate complexes and UO{sub 2}PO{sub 4}{sup -}. The DGT technique did not provide significant advantages over conventional methods to predict uranium uptake by plants.

Diffusive gradient in thin FILMS (DGT) compared with soil solution and labile uranium fraction for predicting uranium bioavailability to ryegrass

International Nuclear Information System (INIS)

Duquene, L.; Vandenhove, H.; Tack, F.; Van Hees, M.; Wannijn, J.

2010-01-01

The usefulness of uranium concentration in soil solution or recovered by selective extraction as unequivocal bioavailability indices for uranium uptake by plants is still unclear. The aim of the present study was to test if the uranium concentration measured by the diffusive gradient in thin films (DGT) technique is a relevant substitute for plant uranium availability in comparison to uranium concentration in the soil solution or uranium recovered by ammonium acetate. Ryegrass (Lolium perenne L. var. Melvina) is grown in greenhouse on a range of uranium spiked soils. The DGT-recovered uranium concentration (C DGT ) was correlated with uranium concentration in the soil solution or with uranium recovered by ammonium acetate extraction. Plant uptake was better predicted by the summed soil solution concentrations of UO 2 2+ , uranyl carbonate complexes and UO 2 PO 4 - . The DGT technique did not provide significant advantages over conventional methods to predict uranium uptake by plants.

The end of cheap uranium

International Nuclear Information System (INIS)

Dittmar, Michael

2013-01-01

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

Recovery of uranium by a reverse osmosis process

International Nuclear Information System (INIS)

Cleary, J.G.; Stana, R.R.

1980-01-01

A method for concentrating and recovering uranium material from an aqueous solution, comprises passing a feed solution containing uranium through at least one reverse osmosis membrane system to concentrate the uranium, and then flushing the concentrated uranium solution with water in a reverse osmosis membrane system to further concentrate the uranium

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

Energy Technology Data Exchange (ETDEWEB)

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

2013-07-01

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

Uranium separation and concentration from ground waters on TIO-PAN sorbent and determination by TRLFS

International Nuclear Information System (INIS)

Raindl, Jakub; Spendlikova, Irena; Nemec, Mojmir; Sebesta, Ferdinand; Zavadilova, Alena; John, Jan

2011-01-01

A new sorbent, viz. hydrated titanium dioxide embedded on a polyacrylonitrile solid support, was tested for the title purpose. Uranium so separated was eluted with 0.1M HCl. Uranium concentrations before and after sorption/elution were determined by time resolved laser induced fluorescence spectroscopy (TRLFS ). The study is aimed at the development of a method suitable for sample preparation for Accelerator Mass Spectrometry (AMS) measurements and at determining the 236 U/U ratio (in cooperation with the VERA facility at the University of Vienna, Austria)

Heavy metal and nitrogen concentrations in mosses are declining across Europe whilst some “hotspots” remain in 2010

International Nuclear Information System (INIS)

Harmens, H.; Norris, D.A.; Sharps, K.; Mills, G.; Alber, R.; Aleksiayenak, Y.; Blum, O.; Cucu-Man, S.-M.; Dam, M.; De Temmerman, L.; Ene, A.; Fernández, J.A.; Martinez-Abaigar, J.; Frontasyeva, M.; Godzik, B.; Jeran, Z.

2015-01-01

In recent decades, naturally growing mosses have been used successfully as biomonitors of atmospheric deposition of heavy metals and nitrogen. Since 1990, the European moss survey has been repeated at five-yearly intervals. In 2010, the lowest concentrations of metals and nitrogen in mosses were generally found in northern Europe, whereas the highest concentrations were observed in (south-)eastern Europe for metals and the central belt for nitrogen. Averaged across Europe, since 1990, the median concentration in mosses has declined the most for lead (77%), followed by vanadium (55%), cadmium (51%), chromium (43%), zinc (34%), nickel (33%), iron (27%), arsenic (21%, since 1995), mercury (14%, since 1995) and copper (11%). Between 2005 and 2010, the decline ranged from 6% for copper to 36% for lead; for nitrogen the decline was 5%. Despite the Europe-wide decline, no changes or increases have been observed between 2005 and 2010 in some (regions of) countries. - Highlights: • In 2010, heavy metal and nitrogen concentrations in mosses were determined at up to 4400 sites across Europe. • Moss concentrations complement deposition measurements at high spatial resolution. • For most metals, concentrations in mosses have significantly declined since 1990. • Heavy metal pollution remains high in (South-)eastern Europe. • Nitrogen pollution remains high in the central European belt. - Heavy metal pollution remains high particularly in (south-)eastern Europe, whereas nitrogen pollution remains high in the central belt of Europe

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.

Design scheme of automatic feeding equipment of domestic uranium chemical concentrate

International Nuclear Information System (INIS)

Hu Jinming; Wang Chao; Peng Jinhui; Zhang Libo

2014-01-01

In order to solve problems by artificial feeding mode with low work efficiency, large intensity manual labor and environmental pollution in domestic uranium concentrate purification process, the design scheme of automatic feeding device was set up, including work flow sheet, composition of automatic equipment and operation. By application of automatic feeding equipment, the feeding speed can be greatly increased, labor force can be reduced, and harm to workman health can be decreased. (authors)

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

International Nuclear Information System (INIS)

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

1981-03-01

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

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

International Nuclear Information System (INIS)

Bommer, P.M.

1979-01-01

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

A database of radionuclide activity and metal concentrations for the Alligator Rivers Region uranium province.

Science.gov (United States)

Doering, Che; Bollhöfer, Andreas

2016-10-01

This paper presents a database of radionuclide activity and metal concentrations for the Alligator Rivers Region (ARR) uranium province in the Australian wet-dry tropics. The database contains 5060 sample records and 57,473 concentration values. The data are for animal, plant, soil, sediment and water samples collected by the Environmental Research Institute of the Supervising Scientist (ERISS) as part of its statutory role to undertake research and monitoring into the impacts of uranium mining on the environment of the ARR. Concentration values are provided in the database for 11 radionuclides ( 227 Ac, 40 K, 210 Pb, 210 Po, 226 Ra, 228 Ra, 228 Th, 230 Th, 232 Th, 234 U, 238 U) and 26 metals (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, P, Pb, Rb, S, Sb, Se, Sr, Th, U, V, Zn). Potential uses of the database are discussed. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Study of some modern carbonated marine organisms, using U234/U238 activities and its uranium concentration

International Nuclear Information System (INIS)

Pregnolatto, Y.

1975-01-01

Several types of alive carbonated organisms of marine fluvial or mixed environment origin were analized in its concentrations of Uranium and about its activity ratio U 234 /U 238 . In the same way measurements were made from the water of these three types of environments. The results indicate that the mollusks shells show a very low concentration compared with corals. Its concentration varies from 0.04 to 0.33 ppm. Inside the limit of errors we can say that the several types of carbonated organisms show the same disequilibrium U 234 /U 238 which was found in associated waters. An analysis of a piece of wood from long time immersed in the sea water was made. The result indicates that there was a marked high in concentration of Uranium due to chelatation with organic matter. (C.D.G.) [pt

Uranium hydrogeochemical and stream sediment reconnaissance of the McGrath and Talkeetna NTMS Quadrangles, Alaska, including concentrations of forty-three additional elements

International Nuclear Information System (INIS)

Aamodt, P.L.; Jacobsen, S.I.; Hill, D.E.

1979-04-01

During the summer of 1977, 1268 water and 1206 sediment samples were collected from 1292 lakes and streams throughout the two quadrangles in south-central Alaska. Each of the water samples was analyzed for uranium and 12 other elements and each of the sediment samples for uranium, thorium, and 41 other elements. Uranium concentrations in water samples range from below 0.02 ppB to 19.64 ppB. In general, lake waters contain somewhat less uranium than stream waters, and the highest concentrations in both sample types were found in or near the Alaska Range. Uranium concentrations in sediment samples range from 0.10 ppM to 172.40 ppM. The highest concentrations are found in samples collected in the Alaska Range near areas of felsic igneous rocks. Sediment samples having high thorium concentrations also come from areas underlain by felsic igneous rocks in the Alaska Range. The following areas were found to be most favorable for significant uranium mineralization: (1) the Windy Fork stock on the southeastern boundary of the McGrath quadrangle; (2) an area in the northwest corner of the Talkeetna quadrangle near the Mespelt prospects; (3) the Hidden River drainage in the northeast corner of the Talkeetna quadrangle; (4) an area near Chelatna Lake in the center of the Talkeetna quadrangle; (5) the Kichatna River drainage, near the western border of the Talkeetna quadrangle; and (6) an area near the Mount Estelle pluton in the extreme southwest corner of the Talkeetna quadrangle

Effect of chloride concentration on the solubility of amorphous uranium dioxide at 25deg C under reducing conditions

International Nuclear Information System (INIS)

Aguilar, M.; Casas, I.; Pablo, J. de; Torrero, M.E.

1991-01-01

The dependence of the solubility of a microcrystalline uranium dioxide on the chloride concentration has been studied at 25deg C under reducing conditions. The concentration of uranium in solution has been found to be some orders of magnitude lower than in perchlorate media. Possible changes of both the morphology and the composition of the solid phase have been investigated by means of Energy Dispersive X-ray Analysis (EDX) and X-ray Powder Difraction (XPD). The formation of a secondary solid phase as a reason for the decrease of the solubility has been postulated. (orig.)

Obtaining of uranium tetrafluoride UF4 by electrodialysis reactive from uranium concentrates

International Nuclear Information System (INIS)

Munoz Lay, Danny Mauricio

2014-01-01

The generation of uranium fuels has always been a topic worldwide. The uranium fuel manufacturing base is made under very strict parameters of radiological and industrial safety, being a stage called 'nuclear fuel cycle'. In Chile, it is done constant research for fuels. This report focuses primarily on participating in such research; mainly in the production of uranium tetrafluoride (UF 4 ) .The tetrafluoride production is very crucial for the nuclear fuel industry. Its production varies from precipitation in stirred conditions to electrolysis in mercury. However, both processes has shortcomings either in performance and environmental pollution, which is why it is proposed a new method of production based on a friendly process to the environment and easier to operate, the reactive electrodialysis (RED). Electrodialysis is a hybrid reactive process of separation by membranes, cationic and / or anionic, namely, ionic species. In the process, ions are induced to move by an electric potential applied and separated by these membranes, a highly selective physical barrier which allows passage of ions with certain charge, and prevents the passage of oppositely charged ions. And in turn, it is reactive because it forces a chemical reaction, redox, to obtain uranium tetrafluoride (UF 4 ). The results of these experiments show that by reactive electrodialysis, NH 4 UF 5 deposits were obtained. However, calcinating the NH 4 UF 5 to 450 o C, it decomposes to obtain uranium tetrafluoride, UF 4 . The best working conditions were obtained with an electric current of 0.5 (A), 41 o C and a flow of 16 (ml / s) of the electrolyte. It was possible to obtain 5,995 (g) to 3 (h), giving a current efficiency of 71.42%. In turn, working at high temperatures and flow recirculation is possible to operate with a potential difference of 1.7 (V)

Seasonal variation in concentration of radon and thoron at non-uranium mines in China

International Nuclear Information System (INIS)

Cui Hongxing; Wu Yunyun; Zhang Qingzhao; Shang Bing

2009-01-01

Objective: To study the seasonal variation in concentrations of radon and thoron in non-uranium mine. Methods: Eight kinds of mineral types from 9 non-uranium mines were selected, including copper, gold, aluminium, manganese, antimonium, tungsten, copper-nickel and coal mines in 6 provinces, such as Yunnan, Shandong, Xinjiang, Heilongjiang, Hunan and Guizhou. LD-P R-T discriminative detectors were used to measure radon and thoron concentrations in underground mines during four seasons in one year. Results: Radon concentrations in underground mines showed a significantly seasonal variation. Radon concentration ranged from 35.5 to 4841 Bq/m 3 in summer, and the average value in four mines exceeded 1000 Bq/m 3 of the control limit for workplace (GB 18871-2002) . In winter, radon concentration ranged from 5 to 1917 Bq/m 3 , only one of them exceeded the control limit. The ratio of radon from summer to winter ranged from 2 to 12. Ventilation was one of the main factors which influenced the seasonal variation of radon. While the thoron concentration in underground mines showed a tendency that it was higher in summer and lower in winter. It was difficult to attain representative values for thoron, due to the influence of location of detectors. The seasonal variation of thoron should be further studied. Conclusions: Seasonal variation for radon and thoron should be taken into account to estimate the effective dose to miners. The values of radon concentration during the short term should be corrected. (authors)

Uranium hydrogeochemical and stream sediment reconnaissance data release for the Rock Springs NTMS Quadrangle, Wyoming, including concentrations of forty-two additional elements

International Nuclear Information System (INIS)

Morgan, T.L.

1981-01-01

This report contains data collected by the Los Alamos Scientific Laboratory (LASL) during a regional geochemical survey for uranium in the Rock Springs National Topographic Map Series (NTMS) quadrangle, southwestern Wyoming, as part of the nationwide hydrogeochemical and Stream Sediment Reconnaissance (HSSR). Totals of 397 water and 1794 sediment samples were collected from 1830 locations in the Rock Springs quadrangle of southern Wyoming during the summer of 1976. The average uranium concentration of all water samples is 6.57 ppb and the average sediment uranium concentration is 3.64 ppM. Elemental concentration, field measurement, weather, geologic, and geographic data for each sample location are listed for waters and for sediments in the appendices. Uranium/thorium ratios for sediment samples are also included. A sample location overlay (Plate I) at 1:250 000 scale for use in conjunction with the Rock Springs NTMS quadrangle sheet (US Geological Survey, 1954) is provided. All elemental analyses were performed at the LASL. Water samples were initially analyzed for uranium by fluorometry. All water samples containing more than 40 ppB uranium were reanalyzed by delayed-neutron counting. Sediments were analyzed for uranium and thorium as well as Al, Sb, Ba, Be, Bi, Cd, Ca, Ce, Cs, Cl, Cr, Co, Cu, Dy, Eu, Au, Hf, Fe, La, Pb, Li, Lu, Mg, Mn, Ni, Nb, K, Rb, Sm, Sc, Ag, Na, Sr, Ta, Tb, Sn, T, W, V, Yb, and Zn. All sediments were analyzed for uranium by delayed-neutron counting. Other elemental concentrations in sediments were determined by neutron-activation analysis for 30 elements, by x-ray fluorescence for 12 elements, and by arc-source emission spectrography for 2 elements. These analytical methods are described briefly in the appendix. This report is simply a data release and is intended to make the data available to the DOE and to the public as quickly as possible

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.)

Uranium hydrogeochemical and stream sediment reconnaissance of the Pueblo NTMS quadrangel, Colorado, including concentrations of forty-three additional elements

International Nuclear Information System (INIS)

Shannon, S.S. Jr.

1978-12-01

This report is a supplement to the HSSR uranium evaluation report for the Pueblo quadrangle (Shannon, 1978), which presented the field and uranium data for the 861 water and 1060 sediment samples collected from 1402 locations in the quadrangle. This supplement presents those data again and the results of subsequent multielement analyses of those HSSR samples. In addition to uranium, the concentrations of 12 elements are presented for the waters and 42 elements for the sediments

Nuclear forensic analysis of an unknown uranium ore concentrate sample seized in a criminal investigation in Australia

International Nuclear Information System (INIS)

Keegan, Elizabeth; Kristo, Michael J.; Colella, Michael; Robel, Martin; Williams, Ross; Lindvall, Rachel; Eppich, Gary; Roberts, Sarah; Borg, Lars; Gaffney, Amy; Plaue, Jonathan; Wong, Henri; Davis, Joel; Loi, Elaine; Reinhard, Mark; Hutcheon, Ian

2014-01-01

In early 2009, a state policing agency raided a clandestine drug laboratory in a suburb of a major city in Australia. While searching the laboratory, they discovered a small glass jar labelled 'Gamma Source' and containing a green powder. The powder was radioactive. This paper documents the detailed nuclear forensic analysis undertaken to characterize and identify the material and determine its provenance. Isotopic and impurity content, phase composition, microstructure and other characteristics were measured on the seized sample, and the results were compared with similar material obtained from the suspected source (ore and ore concentrate material). While an extensive range of parameters were measured, the key 'nuclear forensic signatures' used to identify the material were the U isotopic composition, Pb and Sr isotope ratios, and the rare earth element pattern. These measurements, in combination with statistical analysis of the elemental and isotopic content of the material against a database of uranium ore concentrates sourced from mines located worldwide, led to the conclusion that the seized material (a uranium ore concentrate of natural isotopic abundance) most likely originated from Mary Kathleen, a former Australian uranium mine

Uranium isotopes in groundwater: their use in prospecting for sandstone-type uranium deposits

International Nuclear Information System (INIS)

Cowart, J.B.; Osmond, J.K.

1977-01-01

The relative abundances of dissolved 238 U and its daughter 234 U appear to be greatly affected as the uranium is transported downdip in sandstone aquifers. In an actively forming uranium accumulation at a reducing barrier, an input of 234 U occurs in proximity to the isotopically non-selective precipitation of uranium from the water. The result is a downdip water much lower in uranium concentration but relatively enriched in 234 U. The measurement of isotopic as well as concentration changes may increase the effectiveness of hydrogeochemical exploration of uranium. The investigation includes the uranium isotopic patterns in aquifers associated with known uranium orebodies in the Powder River and Shirley Basins, Wyoming, and Karnes County, Texas, USA. In addition, the Carrizo sandstone aquifer of Texas was studied in detail and the presence of an uranium accumulation inferred

Uranium concentration by Crustacea: a structural, ultrastructural and microanalytical study by secondary ion emission and electron probe X ray microanalysis

International Nuclear Information System (INIS)

Chassard-Bouchaud, Colette

1982-01-01

Experimental intoxications were performed on the Crayfish Pontastacus leptodactylus using hydrosoluble uranium nitrate. Investigations demonstrate that Crustacea are able to concentrate both uranium main radioactive isotopes 238 U and 235 U within the cuticle, gill epithelium, midgut gland (=hepatopancreas) and macrophagic hemocytes. The storage occurs within nucleus and lysosomal system where uranium is precipitated in the form of an unsoluble phosphate. The proposed hypothesis for the metal extrusion is the following: residual bodies containing the uranium precipitates are extruded into the extracellular space where they are absorbed by phagocytosis, by the macrophagic hemocytes [fr

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

International Nuclear Information System (INIS)

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

2008-01-01

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

South African uranium resources - 1997 assessment methodology and results

International Nuclear Information System (INIS)

Ainslie, L.C.

2001-01-01

The first commercial uranium production in South Africa started in 1953 to meet the demand for British/US nuclear weapons. This early production reached its peak in 1959 and began to decline with the reduced demand. The world oil crisis in the 1970s sparked a second resurgence of increased uranium production that peaked in 1980 to over 6,000 tonnes. Poor market condition allied with increasing political isolation resulted in uranium production declining to less than a third of the levels achieved in the early 1980s. South Africa is well endowed with uranium resource. Its uranium resources in the RAR and EAR-I categories, extractable at costs of less than $80/kg U, as of 1 January 1997, are estimated to 284 400 tonnes U. Nearly two thirds of these resources are associated with the gold deposits in the Witwatersrand conglomerates. Most of the remaining resources occur in the Karoo sandstone and coal deposits. (author)

Determination of thorium, uranium and potassium elemental concentrations in surface soils in Cyprus

International Nuclear Information System (INIS)

Tzortzis, Michalis; Tsertos, Haralabos

2004-01-01

A comprehensive study was conducted to determine thorium, uranium and potassium elemental concentrations in surface soils throughout the accessible area of Cyprus using high-resolution γ-ray spectrometry. A total of 115 soil samples was collected from all over the bedrock surface of the island based on the different lithological units of the study area. The soil samples were air-dried, sieved through a fine mesh, sealed in 1000-ml plastic Marinelli beakers, and measured in the laboratory in terms of their gamma radioactivity for a counting time of 18 h each. From the measured γ-ray spectra, elemental concentrations were determined for thorium (range from 2.5x10 -3 to 9.8 μg g -1 ), uranium (from 8.1x10 -4 to 3.2 μg g -1 ) and potassium (from 1.3x10 -4 to 1.9%). The arithmetic mean values (A.M.±S.D.) calculated from all samples are: (1.2±1.7) μg g -1 , (0.6±0.7) μg g -1 and (0.4±0.3)%, for thorium, uranium and potassium, respectively, which are by a factor of three-six lower than the world average values of 7.4 μg g -1 (Th), 2.8 μg g -1 (U) and 1.3% (K) derived from all data available worldwide. The best-fitting relation between the concentrations of Th and K versus U and also of K versus Th, is essentially of linear type with a correlation coefficient of 0.93, 0.84 and 0.90, respectively. The Th/U, K/U and K/Th ratios (slopes) extracted are equal to 2.0, 2.8x10 3 and 1.4x10 3 , respectively

Changes of uranium market price and trend in recent years

International Nuclear Information System (INIS)

Wang Xingwu; Chen Zuyi

2008-01-01

The market price (especially the spot price ) of uranium has experienced significant changes since 2004. Several stages of uranium price are summed up. It is the slow increase period of uranium price from 1991 to 2004, The uranium price rapid rise from 2005 to 2007. The price of uranium jumped sharply from the fourth quarter 2006 to first half of 2007. The price of uranium rapid declined and tended to be stable from second half 2007 to this day. Characteristics, reason and change trend of uranium price in these stages are summarized. (authors)

Measurement of the radioactive concentration in consumer's goods containing natural uranium and thorium and evaluation of the exposure by their utilization

International Nuclear Information System (INIS)

Yoshida, Masahiro; Satou, Shigerou; Ohhata, Tsutomu; Watanabe, Masatoshi; Ohyama, Ryutaro; Furuya, Hirotaka; Endou, Akira

2005-01-01

A number of consumer's goods which contain natural uranium and thorium are circulated in the familiar living environment. Based on various kinds of information sources, 20 kinds of these consumer's goods were collected and their radioactive concentrations were measured by using ICP-MS and Ge semiconductor detector. As this result, it was found that the concentrations of uranium and thorium in the consumer's goods used at home and industries were below 34 Bq/g and below 270 Bq/g, respectively. Next, the concentrations of daughter nuclides were not so different from the ones of uranium or thorium, which showed that the secular radioactive equilibrium held between both concentrations. In addition, the radiation exposures for public consumer were evaluated when four kinds of typical consumer's goods frequently used in daily life are utilized. The results computed by MCNP-4C code were below 250 μSv/y. (author)

Influence of Uranium and Polivinyl Alcohol Concentration in the Feed of Sol Gel Process on the Gel Spherical Product

International Nuclear Information System (INIS)

Indra Suryawan; Endang Susiantini

2007-01-01

The gel particles have been made at various uranium and polyvinyl alcohol concentration in the sol gel process. The variables of uranium concentration were 0.3; 0.5; 0.7; 0.9; 1.1; 1.3; 1.5; 1.7; 1.9 and 2.1 M The variables of polyvinyl alcohol concentration were 0.3; 0.6; 0.9; 1.2; 1.5; 1.8; 2.1 and 2.4 M After drying the sol gel process products were heated at 300, 500 and 750°C during 4 hours. The gel particles were characterized using an optic microscope to know the shape and condition morphology of gel. From experimental result using uranium concentration of 0.3 until 2.1 M and polyvinyl alcohol of 1.8 until 2.4 M spherical and gel was formed elastic, after heating at 750°C it was unbreakable. At the concentration of polyvinyl alcohol from 0.3 to 0.5 M, the gel product was soft and broken after being dried. At the concentration of polyvinyl alcohol from 0.6 to 0.8 M, the dried gel product was not perfect. At the concentration of polyvinyl alcohol from 0.9 to 1.7 M, the gel product of gelation process was spherical and it was broken after being heated up to 300°C. (author)

The kinetics of the cerium(IV)-uranium(IV) reaction at low sulfate concentrations

International Nuclear Information System (INIS)

Michaille, P.; Kikindai, T.

1977-01-01

The rate of oxidation of uranium(IV) by cerium(IV) was measured with a stopped-flow spectrophotometer at sulfuric acid concentrations of 2 x 10 -6 to 0.5 M. At a constant hydrogen ion concentration of 0.5 M, the maximum rate constant was observed for 2 x 10 -3 M sulfuric acid; at that concentration, two sulfate ions were involved in the activated complex. The dependence of the rate constant on the hydrogen ion concentration showed that the reaction paths involving one or two sulfate ions also involved one hydroxyl ion, whereas one hydrogen ion was involved in the five sulfate dependent path. Spectrophotometric measurements supported the existence of a hydrolyzed monosulfatocomplex of cerium(IV). (author)

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)

Uranium refining by solvent extraction

International Nuclear Information System (INIS)

Kraikaew, J.; Srinuttrakul, W.

2014-01-01

The solvent extraction process to produce higher purity uranium from yellowcake was studied in laboratory scale. Yellowcake, which the uranium purity is around 70% and the main impurity is thorium, was obtained from monazite processing pilot plant of Rare Earth Research and Development Center in Thailand. For uranium re-extraction process, the extractant chosen was Tributylphosphate (TBP) in kerosene. It was found that the optimum concentration of TBP was 10% in kerosene and the optimum nitric acid concentration in uranyl nitrate feed solution was 4 N. An increase in concentrations of uranium and thorium in feed solution resulted in a decrease in the distribution of both components in the extractant. However, the distribution of uranium into the extractant was found to be more than that of thorium. The equilibration study of the extraction system, UO_2(NO_3)/4N HNO_3 – 10%TBP/Kerosene, was also investigated. Two extraction stages were calculated graphically from 100,000 ppm uranium concentration in feed solution input with 90% extraction efficiency and the flow ratio of aqueous phase to organic phase was adjusted to 1.0. For thorium impurity scrubbing process, 10% TBP in kerosene was loaded with uranium and minor thorium from uranyl nitrate solution prepared from yellowcake and was scrubbed with different low concentration nitric acid. The results showed that at nitric acid normality was lower than 1 N, uranium distributed well to aqueous phase. As conclusion, optimum nitric acid concentration for scrubbing process should not less than 1 N and diluted nitric acid or de-ionized water should be applied to strip uranium from organic phase in the final refining process. (author)

Refining of crude uranium by solvent extraction for production of nuclear pure uranium metal

International Nuclear Information System (INIS)

Gupta, S.K.; Manna, S.; Singha, M.; Hareendran, K.N.; Chowdhury, S.; Satpati, S.K.; Kumar, K.

2007-01-01

Uranium is the primary fuel material for any nuclear fission energy program. Natural uranium contains only 0.712% of 235 U as fissile constituent. This low concentration of fissile isotope in natural uranium calls for a very high level of purity, especially with respect to neutron poisons like B, Cd, Gd etc. before it can be used as nuclear fuel. Solvent extraction is a widely used technique by which crude uranium is purified for reactor use. Uranium metal plant (UMP), BARC, Trombay is engaged in refining of uranium concentrate for production of nuclear pure uranium metal for fabrication of fuel for research reactors. This paper reviews some of the fundamental aspects of this refining process with some special references to UMP, BARC. (author)

Formation conditions of uranium minerals in oxidation zone of uranium deposits

International Nuclear Information System (INIS)

Li Youzhu

2005-01-01

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

Standard practices for sampling uranium-Ore concentrate

CERN Document Server

American Society for Testing and Materials. Philadelphia

2010-01-01

1.1 These practices are intended to provide the nuclear industry with procedures for obtaining representative bulk samples from uranium-ore concentrates (UOC) (see Specification C967). 1.2 These practices also provide for obtaining a series of representative secondary samples from the original bulk sample for the determination of moisture and other test purposes, and for the preparation of pulverized analytical samples (see Test Methods C1022). 1.3 These practices consist of a number of alternative procedures for sampling and sample preparation which have been shown to be satisfactory through long experience in the nuclear industry. These procedures are described in the following order. Stage Procedure Section Primary Sampling One-stage falling stream 4 Two-stage falling stream 5 Auger 6 Secondary Sampling Straight-path (reciprocating) 7 Rotating (Vezin) 8, 9 Sample Preparation 10 Concurrent-drying 11-13 Natural moisture 14-16 Calcination 17, 18 Sample Packaging 19 Wax s...

Current uranium activities in Pakistan

International Nuclear Information System (INIS)

Moghal, M.Y.

2001-01-01

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

The prospects for Canadian uranium

International Nuclear Information System (INIS)

Salaff, S.

1983-07-01

The 1980s have seen a decline in markets for uranium concentrate, largely as a result of falling estimates for reactor fuel requirements and rising inventories. Spot market prices fell to $44 in September 1982, but have since risen back to $60. World production also fell in 1982 and is not expected to increase significantly before 1990. Some opportunities exist for Canadian producers with new low-cost deposits to replace high-cost producers in Canada and other countries, particularly the United States. There will be strong competition between Canadian producers as well as from Australia. Australia's reserves are somewhat larger than Canada's, although the reported ore grades tend to be lower than those of Saskatchewan

Metals other than uranium affected microbial community composition in a historical uranium-mining site.

Science.gov (United States)

Sitte, Jana; Löffler, Sylvia; Burkhardt, Eva-Maria; Goldfarb, Katherine C; Büchel, Georg; Hazen, Terry C; Küsel, Kirsten

2015-12-01

To understand the links between the long-term impact of uranium and other metals on microbial community composition, ground- and surface water-influenced soils varying greatly in uranium and metal concentrations were investigated at the former uranium-mining district in Ronneburg, Germany. A soil-based 16S PhyloChip approach revealed 2358 bacterial and 35 archaeal operational taxonomic units (OTU) within diverse phylogenetic groups with higher OTU numbers than at other uranium-contaminated sites, e.g., at Oak Ridge. Iron- and sulfate-reducing bacteria (FeRB and SRB), which have the potential to attenuate uranium and other metals by the enzymatic and/or abiotic reduction of metal ions, were found at all sites. Although soil concentrations of solid-phase uranium were high, ranging from 5 to 1569 μg·g (dry weight) soil(-1), redundancy analysis (RDA) and forward selection indicated that neither total nor bio-available uranium concentrations contributed significantly to the observed OTU distribution. Instead, microbial community composition appeared to be influenced more by redox potential. Bacterial communities were also influenced by bio-available manganese and total cobalt and cadmium concentrations. Bio-available cadmium impacted FeRB distribution while bio-available manganese and copper as well as solid-phase zinc concentrations in the soil affected SRB composition. Archaeal communities were influenced by the bio-available lead as well as total zinc and cobalt concentrations. These results suggest that (i) microbial richness was not impacted by heavy metals and radionuclides and that (ii) redox potential and secondary metal contaminants had the strongest effect on microbial community composition, as opposed to uranium, the primary source of contamination.

Uranium hydrogeochemical and stream sediment reconnaissance of the Dalhart NTMS quadrangle, New Mexico/Texas/Oklahoma, including concentrations of forty-two additional elements

International Nuclear Information System (INIS)

Morgan, T.L.

1980-08-01

Totals of 1583 water samples and 503 sediment samples were collected from 2028 locations within the 20 000-km 2 area of the quadrangle at an average density of one location per 9.86 km 2 . Water samples were collected from wells, springs, and streams and were analyzed for uranium. Sediment samples were collected from streams and springs and were analyzed for uranium, thorium, and 41 additional elements. All field and analytical data are listed in the appendixes of this report. Discussion is limited to anomalous samples, which are considered to be those containing over 20 ppB uranium for waters and over 5 ppM uranium for sediments. Uranium concentrations in water samples range from below the detection limit of 0.2 ppB to 1457.65 ppB and average 7.41 ppB. Most of the seventy anomalous water samples (4.4% of all water samples) are grouped spatially into five clusters or areas of interest. Samples in three of the clusters were collected along the north edge of the quadrangle where Mesozoic strata are exposed. The other two clusters are from the central and southern portions where the Quaternary Ogallala formation is exposed. Sediment samples from the quadrangle have uranium concentrations that range from 0.90 ppM to 27.20 ppM and average 3.27 ppM. Fourteen samples (2.8% of all sediment samples) contain over 5 ppM uranium and are considered anomalous. The five samples with the highest concentrations occur where downcutting streams expose Cretaceous units beneath the Quaternary surficial deposits. The remaining anomalous sediment samples were collected from scattered locations and do not indicate any single formation or unit as a potential source for the anomalous concentrations

Fission track method for uranium ore exploration

International Nuclear Information System (INIS)

Guo Shilun; Deng Xinlu; Sun Shengfen; Meng Wu; Zhang Pengfa; Hao Xiuhong

1986-01-01

The uranium concentrations in natural water collected in the fields of uranium ore exploration with fission track method have been determined. It shows that the results of fission track method are consistent with that of fluoro-colorimetry and laser fluorometry for the same samples of water with uranium concentration in the region of 10 -4 to 10 -8 g/l. For water samples with lower uranium concentration (≤10 -8 g/l), the fission track method can still give accurate or referential results, but the other two methods failed. The reproducibility of fission track method was checked and discussed by using samples collected in the same fields of uranium ore exploration. The effects of the concentration of the impurities in natural water on determination of uranium concentration were analysed and discussed as well

Radiation dose-dependent risk on individuals due to ingestion of uranium and radon concentration in drinking water samples of four districts of Haryana, India

Science.gov (United States)

Panghal, Amanjeet; Kumar, Ajay; Kumar, Suneel; Singh, Joga; Sharma, Sumit; Singh, Parminder; Mehra, Rohit; Bajwa, B. S.

2017-06-01

Uranium gets into drinking water when the minerals containing uranium are dissolved in groundwater. Uranium and radon concentrations have been measured in drinking water samples from different water sources such as hand pumps, tube wells and bore wells at different depths from various locations of four districts (Jind, Rohtak, Panipat and Sonipat) of Haryana, India, using the LED flourimetry technique and RAD7, electronic silicon solid state detector. The uranium (238U) and radon (222Rn) concentrations in water samples have been found to vary from 1.07 to 40.25 µg L-1 with an average of 17.91 µg L-1 and 16.06 ± 0.97 to 57.35 ± 1.28 Bq L-1 with an average of 32.98 ± 2.45 Bq L-1, respectively. The observed value of radon concentration in 43 samples exceeded the recommended limits of 11 Bq L-1 (USEPA) and all the values are within the European Commission recommended limit of 100 Bq L-1. The average value of uranium concentration is observed to be within the safe limit recommended by World Health Organization (WHO) and Atomic Energy Regulatory Board. The annual effective dose has also been measured in all the water samples and is found to be below the prescribed dose limit of 100 µSv y-1 recommended by WHO. Risk assessment of uranium in water is also calculated using life time cancer risk, life time average daily dose and hazard quotient. The high uranium concentration observed in certain areas is due to interaction of ground water with the soil formation of this region and the local subsurface geology of the region.

Recovery and treatment of uranium from uranium-containing solution by liquid membrane emulsion technology

International Nuclear Information System (INIS)

Xia Liangshu; Zhou Yantong; Xiao Yiqun; Peng Anguo; Xiao Jingshui; Chen Wei

2014-01-01

The recovery and treatment of uranium from uranium-containing solution using liquid membrane emulsion (LME) technology were studied in this paper, which contained the best volume ratio of membrane materials, stirring speed during emulsion process, the conditions of extracting, such as temperature, pH, initial concentration of uranium. Moreover, the mechanism for extracting uranium was also discussed. The best experimental conditions of emulsifying were acquired. The volume fractions of P 204 and liquid paraffin are 0.1 and 0.05, the volume ratios of Span80 and sulphonated kerosene to P 204 are 0.06 and 0.79 respectively, stirring speed is controlled in 2 000 r/min, and the concentration of inner phase is 4 mol/L. The recovery rate of uranium is up to 99% through the LME extracted uranium for 0.5 h at pH 2.5 and room temperature when the initial concentration is less than 400 mg/L and the volume ratio is 5 between the uranium-containing waste water and LME. The calculation results of Gibbs free energy show that the reaction process is spontaneous. (authors)

Determination of uranium in uranium metal, uranium oxides, and uranyl nitrate solutions by potentiometric titration

International Nuclear Information System (INIS)

Tucker, H.L.; McElhaney, R.J.

1983-01-01

A simple, fast method for the determination of uranium in uranium metal, uranium oxides, and uranyl nitrate solutions has been adapted from the Davies-Gray volumetric method to meet the needs of Y-12. One-gram duplicate aliquots of uranium metal or uranium oxide are dissolved in 1:1 HNO 3 and concentrated H 2 SO 4 to sulfur trioxide fumes, and then diluted to 100-mL volume. Duplicate aliquots are then weighed for analysis. For uranyl nitrate samples, duplicate aliquots containing between 50 and 150 mg of U are weighed and analyzed directly. The weighed aliquot is transferred to a Berzelius beaker; 1.5 M sulfamic acid is added, followed in order by concentrated phosphoric acid, 1 M ferrous sulfate, and (after a 30-second interval) the oxidizing reagent. After a timed 3-minute waiting period, 100 mL of the 0.1% vanadyl sulfate-sulfuric acid mixture is added. The sample is then titrated past its endpoint with standard potassium dichromate, and the endpoint is determined by second derivative techniques on a mV/weight basis

International uranium supply to the US market

International Nuclear Information System (INIS)

Bonny, J.

1987-01-01

The 1980s have seen a major redistribution of global uranium production. Since 1984, the first full year of production from the Key Lake Mine, Canada has displaced the US as the world's largest uranium producer. Uranium production in the US has stabilized in the range of 10 to 15 million lb U 3 O 8 per year, having declined from a peak of over 43 million lb in 1980. Production from Africa and Europe has declined slightly, and Australia, with the startup of Ranger Mine, has emerged as a significant producer. The main factors that have affected the distribution of production aside from price and demand are ore grades and production costs, currency exchange rates, long-term contracts, and tied supply. It is interesting to examine uranium supply and demand for the North American continent. In 1980 and 1981, North American production was more than twice reactor requirements. By 1985, however, requirements were only slightly lower than production, a situation that has persisted into 1987. Indeed, given the export commitments by Canadian and US producers to Europe and Asia, it is apparent that the US must import uranium from other countries. The relative balance in North American supply and demand suggests that free trade between Canada and the US for both uranium and conversion services would be beneficial to both countries

Uranium contamination of drinking water in Kazakhstan and Uzbekistan

International Nuclear Information System (INIS)

Kawabata, Y.; Aparin, V.; Shiraishi, K.; Ko, S.; Yamamoto, M.; Nagaia, M.; Katayama, Y.

2006-01-01

Uranium is a naturally occurring radioactive metal, and is widely distributed in the Earth's crust. But it is concentrated in certain rock formations. Most of the uranium for nuclear weapon produced in the Soviet Union during the Cold War came from Central Asia. Uranium has negative effects on the human body, both as a carcinogen and as a kidney toxin. WHO (2004) prescribed that uranium concentrations in drinking water should be less than 15 mcg/l for only chemical aspects of uranium addressed. We determined high uranium concentrations in drinking water in the central region of Uzbekistan (Y. KAWABATA et al. 2004). In this area, some discharge water from farmland has higher uranium concentration. Irrigation systems Kyzyl-orda in Republic of Kazakhstan and in Karakalpakstan in the Republic of Uzbekistan have drains deeper than 5 m, in order to protect against salinization. Water in these drains can mix with ground water. In this area, ground water is used for drinking water. We investigated uranium concentrations in water in Kazakhstan and Uzbekistan. In the half of drinking water sampling points, uranium concentrations exceeded the WHO (2004) guideline level for drinking water. Uranium is a suspected carcinogen that can also have a toxic effect on kidney. However, WHO addresses only the chemical aspects of uranium by giving uranium concentrations in drinking water. The effect of uranium exposure from drinking water on people in these areas is significant. The uranium concentration in the Aral Sea was higher than that in sea water. Aral Sea is accumulating uranium. (author)

Concentrations and biological availability of 238U and 230Th in the environs of a uranium milling operation

International Nuclear Information System (INIS)

Ibrahim, S.; Flot, S.; Whicker, F.W.

1982-01-01

This paper reports on a study whose objectives were to determine 238 U and 230 Th concentrations in soil and native plants from various sites around a conventional acid leach uranium milling operation in the Western US, and to estimate plant/soil concentration factors. Soil and vegetation samples were collected from exposed, weathered tailings; near the edge of a tailings pond; from a reclamation area; and at several native range background (control) locations. The results indicate that mean plant/soil concentration factors varied significantly among sites and between radionuclides, but no significant differences between plant groups were found. Concentration factors for 230 Th were greater than for 238 U for plants growing at the edge of the tailings pond. It is speculated that the lower concentration factors for uranium relative to thorium at this site may be due to the proportion of their contents in soil that is biologically available for plant uptake

Pre-concentration of uranium from water samples by dispersive liquid-liquid micro-extraction

Energy Technology Data Exchange (ETDEWEB)

Khajeh, Mostafa; Nemch, Tabandeh Karimi [Zabol Univ. (Iran, Islamic Republic of). Dept. of Chemistry

2014-07-01

In this study, a simple and rapid dispersive liquid-liquid microextraction (DLLME) was developed for the determination of uranium in water samples prior to high performance liquid chromatography with diode array detection. 1-(2-pyridylazo)-2-naphthol (PAN) was used as complexing agent. The effect of various parameters on the extraction step including type and volume of extraction and dispersive solvents, pH of solution, concentration of PAN, extraction time, sample volume and ionic strength were studied and optimized. Under the optimum conditions, the limit of detection (LOD) and preconcentration factor were 0.3 μg L{sup -1} and 194, respectively. Furthermore, the relative standard deviation of the ten replicate was <2.6%. The developed procedure was then applied to the extraction and determination of uranium in the water samples.

Pre-concentration of uranium from water samples by dispersive liquid-liquid micro-extraction

International Nuclear Information System (INIS)

Khajeh, Mostafa; Nemch, Tabandeh Karimi

2014-01-01

In this study, a simple and rapid dispersive liquid-liquid microextraction (DLLME) was developed for the determination of uranium in water samples prior to high performance liquid chromatography with diode array detection. 1-(2-pyridylazo)-2-naphthol (PAN) was used as complexing agent. The effect of various parameters on the extraction step including type and volume of extraction and dispersive solvents, pH of solution, concentration of PAN, extraction time, sample volume and ionic strength were studied and optimized. Under the optimum conditions, the limit of detection (LOD) and preconcentration factor were 0.3 μg L -1 and 194, respectively. Furthermore, the relative standard deviation of the ten replicate was <2.6%. The developed procedure was then applied to the extraction and determination of uranium in the water samples.

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

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)

Uranium Metal Analysis via Selective Dissolution

Energy Technology Data Exchange (ETDEWEB)

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

2008-09-10

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

Strategy of uranium exploration in Indonesia facing uranium price decreacing trend

International Nuclear Information System (INIS)

Karyono, H.S.

1996-01-01

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

Wet high-intensity magnetic separation for the concentration of Witwatersrand gold-uranium ores and residues

International Nuclear Information System (INIS)

Corrans, I.J.; Levin, J.

1979-01-01

Wet high-intensity magnetic separation (WHIMS) for the concentration of gold and uranium was tested on many Witwatersrand cyanidation residues, and on some ores and flotation tailings. The results varied, but many indicated recoveries of over 60 per cent of the gold and uranium. The main source of loss is the inefficiency of WHIMS for material of smaller particle size than 20μm. The recoveries in the continuous tests were lower than those in the batch tests. The continuous tests indicated an operational difficulty that could be experienced in practice, namely the tendency for wood chips and ferromagnetic particles to block the matrix of the separator. It was decided that a solution to the problem lies in the modification of the separator to allow continuous removal of the matrix for cleaning. A system has been developed for this purpose and is being demonstrated on a pilot-plant scale. Promising results were obtained in tests on a process that combines a coarse grind, gravity concentration, and WHIMS. In the gravity-concentration step, considerable recoveries, generally over 50 per cent, of high-grade pyrite were obtained, together with high recoveries of gold and moderate, but possibly important, recoveries of uranium. A simple model describing the operation of the WHIMS machine in terms of the operating parameters is described. This should reduce the amount of empirical testwork required for the optimization of operating conditions and should provide a basis for scale-up calculations. The economics of the WHIMS process is discussed [af

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

Science.gov (United States)

Jha, V N; Tripathi, R M; Sethy, N K; Sahoo, S K

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, puranium concentration in plant and the substrate (r=0.88, puranium concentration was significantly correlated with Mn, Fe, and Ni concentration of plants (puranium accumulation and concentration ratio can be useful for prospecting phytoremediation of stream carrying treated or untreated uranium mill tailings effluent. Copyright © 2015 Elsevier B.V. All rights reserved.

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.

Uranium Industry Annual, 1992

International Nuclear Information System (INIS)

1993-01-01

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

Uranium Industry Annual, 1992

Energy Technology Data Exchange (ETDEWEB)

1993-10-28

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

PAH concentrations in lake sediment decline following ban on coal-tar-based pavement sealants in Austin, Texas

Science.gov (United States)

Van Metre, Peter C.; Mahler, Barbara J.

2013-01-01

Recent studies have concluded that coal-tar-based pavement sealants are a major source of polycyclic aromatic hydrocarbons (PAHs) in urban settings in large parts of the United States. In 2006, Austin, TX, became the first jurisdiction in the U.S. to ban the use of coal-tar sealants. We evaluated the effect of Austin’s ban by analyzing PAHs in sediment cores and bottom-sediment samples collected in 1998, 2000, 2001, 2012, and 2014 from Lady Bird Lake, the principal receiving water body for Austin urban runoff. The sum concentration of the 16 EPA Priority Pollutant PAHs (∑PAH16) in dated core intervals and surficial bottom-sediment samples collected from sites in the lower lake declined about 44% from 1998–2005 to 2006–2014 (means of 7980 and 4500 μg kg–1, respectively), and by 2012–2014, the decline was about 58% (mean of 3320 μg kg–1). Concentrations of ∑PAH16 in bottom sediment from two of three mid-lake sites decreased by about 71 and 35% from 2001 to 2014. Concentrations at a third site increased by about 14% from 2001 to 2014. The decreases since 2006 reverse a 40-year (1959–1998) upward trend. Despite declines in PAH concentrations, PAH profiles and source-receptor modeling results indicate that coal-tar sealants remain the largest PAH source to the lake, implying that PAH concentrations likely will continue to decline as stocks of previously applied sealant gradually become depleted.

Optimization of Davies and Gray/NBL method used for determination of total uranium concentration in the safeguards destructive analysis

International Nuclear Information System (INIS)

Silva, Jose Wanderley S. da; Viana, Aline Gonzalez; Barros, Pedro Dionisio de; Cristiano, Barbara Fernandes G.

2013-01-01

One important activity conducted by the Brazilian State System of Accounting for and Control of Nuclear Materials - SSAC is to verify inventories of the nuclear facilities by nondestructive analysis and destructive analysis. For destructive analysis, the Safeguards Laboratory of Brazilian Nuclear Energy Commission - LASAL/CNEN has been applying the 'Davies and Gray/NBL' method in samples taken during inspections at nuclear facilities since 1984 in Brazil and Argentina. This method consists of the determination of total uranium concentration by potentiometric titration of uranium (IV) with a standard solution of potassium dichromate as oxidizing agent. This solution is prepared using a K 2 Cr 2 O 7 SRM 136e standard reference material (99.984 ±0.010) wt% certified by National Institute of Standard and Technology - NIST. The procedure also includes the calibration with primary uranium standards reference material (NBL CRM 112A). In order to reduce the consumption of K 2 Cr 2 O 7 and the other reagent involved in the procedure, without any loss in the performance of the method, a K 2 Cr 2 O 7 solution with half the regular concentration was prepared and used to test the uranium concentration in several aliquots with a content between 30 mg to 40 mg of uranium per gram of solution. After optimizing the parameters and procedure, it was possible to get the same performance as well. As a consequence, decreasing of the cost, the amount of waste and also a reduction in the titration time of each aliquot was achieved. Thus, this work describes all details in this research as well as the results and its evaluation. (author)

Method for the recovery of uranium from a concentrate using pure phosphoric acid

International Nuclear Information System (INIS)

1980-01-01

Procedure for the recovery of an uranium bearing concentrate and pure phosphoric acid from a wet process phosphoric acid from the treatment fluid with a precipitation means in conjunction with an organic diluent, the thus formed precipitate to separate and from the remaining mixture of phosphoric acid and diluent the phosphoric acid to extract, characterised in that one applies an inorganic fluorine compound. (G.C.)

Baccharis Salicifolia development in the presence of high concentrations of uranium in the arid environment of San Marcos, Chihuahua

Energy Technology Data Exchange (ETDEWEB)

Luna P, M. Y.; Alarcon H, M. T.; Silva S, M.; Renteria V, M; Rodriguez V, M. A.; Herrera P, E.; Reyes C, M.; Montero C, M. E., E-mail: elena.montero@cimav.edu.m [Centro de Investigacion en Materiales Avanzados, S. C., Miguel de Cervantes 120, Complejo Industrial Chihuahua, 31109 Chihuahua (Mexico)

2011-02-15

In humid zones and marine environments the bio indicator contaminants by trace elements are well established. However, in arid zones it is more difficult to find these tools because there is less biodiversity. The objective of this paper was to analyze the behavior of the Baccharis salicifolia plant in areas with high uranium concentration in arid zones, to determine the characteristics of tolerance and possible use as a bio monitor for the presence of such contaminants. For this project a uraniferous zone was selected in San Marcos, located northwest of the City of Chihuahua. A total of 8 sampling points of the plant and soil were located here. Each sample was divided into the root and the stem and leaves to determine the specific activity of the uranium in both parts of the plant and its sediments. The determination of the specific activities of the total uranium in the samples was obtained by liquid scintillation with alpha-beta separation. The results indicate a tendency for the plant to accumulate the uranium in its different parts, and to trans locate it to its stem and leaves. The plant is resistant to high concentrations of uranium, not showing any specific changes in relation to non contaminated areas that might indicate the presence of the contaminant. Therefore, its use as a bio monitor species is limited. (Author)

Baccharis Salicifolia development in the presence of high concentrations of uranium in the arid environment of San Marcos, Chihuahua

International Nuclear Information System (INIS)

Luna P, M. Y.; Alarcon H, M. T.; Silva S, M.; Renteria V, M; Rodriguez V, M. A.; Herrera P, E.; Reyes C, M.; Montero C, M. E.

2011-01-01

In humid zones and marine environments the bio indicator contaminants by trace elements are well established. However, in arid zones it is more difficult to find these tools because there is less biodiversity. The objective of this paper was to analyze the behavior of the Baccharis salicifolia plant in areas with high uranium concentration in arid zones, to determine the characteristics of tolerance and possible use as a bio monitor for the presence of such contaminants. For this project a uraniferous zone was selected in San Marcos, located northwest of the City of Chihuahua. A total of 8 sampling points of the plant and soil were located here. Each sample was divided into the root and the stem and leaves to determine the specific activity of the uranium in both parts of the plant and its sediments. The determination of the specific activities of the total uranium in the samples was obtained by liquid scintillation with alpha-beta separation. The results indicate a tendency for the plant to accumulate the uranium in its different parts, and to trans locate it to its stem and leaves. The plant is resistant to high concentrations of uranium, not showing any specific changes in relation to non contaminated areas that might indicate the presence of the contaminant. Therefore, its use as a bio monitor species is limited. (Author)

Microbial links between sulfate reduction and metal retention in uranium- and heavy metal-contaminated soil.

Science.gov (United States)

Sitte, Jana; Akob, Denise M; Kaufmann, Christian; Finster, Kai; Banerjee, Dipanjan; Burkhardt, Eva-Maria; Kostka, Joel E; Scheinost, Andreas C; Büchel, Georg; Küsel, Kirsten

2010-05-01

Sulfate-reducing bacteria (SRB) can affect metal mobility either directly by reductive transformation of metal ions, e.g., uranium, into their insoluble forms or indirectly by formation of metal sulfides. This study evaluated in situ and biostimulated activity of SRB in groundwater-influenced soils from a creek bank contaminated with heavy metals and radionuclides within the former uranium mining district of Ronneburg, Germany. In situ activity of SRB, measured by the (35)SO(4)(2-) radiotracer method, was restricted to reduced soil horizons with rates of metals were enriched in the solid phase of the reduced horizons, whereas pore water concentrations were low. X-ray absorption near-edge structure (XANES) measurements demonstrated that approximately 80% of uranium was present as reduced uranium but appeared to occur as a sorbed complex. Soil-based dsrAB clone libraries were dominated by sequences affiliated with members of the Desulfobacterales but also the Desulfovibrionales, Syntrophobacteraceae, and Clostridiales. [(13)C]acetate- and [(13)C]lactate-biostimulated soil microcosms were dominated by sulfate and Fe(III) reduction. These processes were associated with enrichment of SRB and Geobacteraceae; enriched SRB were closely related to organisms detected in soils by using the dsrAB marker. Concentrations of soluble nickel, cobalt, and occasionally zinc declined uranium increased in carbon-amended treatments, reaching metal attenuation and (ii) the fate of uranium mobility is not predictable and may lead to downstream contamination of adjacent ecosystems.

Investigation of Great Basin big sagebrush and black greasewood as biogeochemical indicators of uranium mineralization. Final report. National Uranium Resource Evaluation

International Nuclear Information System (INIS)

Diebold, F.E.; McGrath, S.

1982-11-01

The effects of varying phosphate concentrations in natural aqueous systems upon the uptake of uranium by big sagebrush (Artemesia tridentata subsp. tridentata) and black greasewood (Sarcobatus vermiculatus (Hook) Torr.) were investigated. Two separate growth experiments with five drip-flow hyroponic units were used and plant seedlings were grown for 60 days in solutions of varying phosphate and uranium concentrations. Successful growth experiments were obtained only for big sagebrush; black greasewood did not sustain sufficient growth. The phosphate concentration of the water did affect the uptake of uranium by the big sagebrush, and this effect is most pronounced in the region of higher concentrations of uranium in the water. The ratio of the concentration of uranium in the plant to that in the water was observed to decrease with increasing uranium concentration in solution. This is indicative of an absorption barrier in the plants. The field data shows that big sagebrush responds to uranium concentrations in the soil water and not the groundwater. The manifestation of these results is that the use of big sagebrush as a biogeochemical indicator of uranium is not recommended. Since the concentration of phosphate must also be knwon in the water supplying the uranium to the plant, one should analyze this natural aqueous phase as a hydrochemical indicator rather than the big sagebrush

Recovery of uranium from crude uranium tetrafluoride

Energy Technology Data Exchange (ETDEWEB)

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

1994-06-01

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

Recovery of uranium from crude uranium tetrafluoride

International Nuclear Information System (INIS)

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

1994-01-01

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

Origin assessment of uranium ore concentrates based on their rare-earth elemental impurity pattern

Energy Technology Data Exchange (ETDEWEB)

Varga, Z.; Wallenius, M.; Mayer, K. [Commission of the European Communities, Karlsruhe (Germany). European Inst. for Transuranium Elements

2010-07-01

The rare-earth element pattern was used as an additional tool for the identification and origin assessment of uranium ore concentrates (yellow cakes) for nuclear forensic purposes. By this means, the source of an unknown material can be straightforwardly verified by comparing the pattern with that of a known or declared sample. In contrast to other indicators used for nuclear forensic studies, the provenance of the material can also be assessed in several cases even if no comparison sample is available due to the characteristic pattern. The milling process was found not to change the pattern and no significant elemental fractionation occurs between the rare-earth elements, thus the pattern in the yellow cakes corresponds to that found in the uranium ore. (orig.)

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)

Fabrication procedures for manufacturing high uranium concentration dispersion fuel elements; Procedimentos de fabricacao de elementos combustiveis a base de dispersoes com alta concentracao de uranio

Energy Technology Data Exchange (ETDEWEB)

Souza, J.A.B.; Durazzo, M., E-mail: jasouza@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2010-07-01

IPEN developed and made available for routine production the technology for manufacturing dispersion type fuel elements for use in research reactors. However, the fuel produced at IPEN is limited to the uranium concentration of 3.0 gU/cm{sup 3} by using the U{sub 3}Si{sub 2}-Al dispersion. Increasing the uranium concentration of the fuel is interesting by the possibility of increasing the reactor core reactivity and lifetime of the fuel. It is possible to increase the concentration of uranium in the fuel up to the technological limit of 4.8 gU/cm{sup 3} for the U{sub 3}Si{sub 2}-Al dispersion, which is well placed around the world. This new fuel will be applicable in the new Brazilian-Multipurpose Reactor RMB. This study aimed to develop the manufacturing process of high uranium concentration fuel, redefining the procedures currently used in the manufacture of IPEN. This paper describes the main procedures adjustments that will be necessary. (author)

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.)

Uranium extraction in phosphoric acid

International Nuclear Information System (INIS)

Araujo Figueiredo, C. de

1984-01-01

Uranium is recovered from the phosphoric liquor produced from the concentrate obtained from phosphorus-uraniferous mineral from Itataia mines (CE, Brazil). The proposed process consists of two extraction cycles. In the first one, uranium is reduced to its tetravalent state and then extracted by dioctylpyrophosphoric acid, diluted in Kerosene. Re-extraction is carried out with concentrated phosphoric acid containing an oxidising agent to convert uranium to its hexavalent state. This extract (from the first cycle) is submitted to the second cycle where uranium is extracted with DEPA-TOPO (di-2-hexylphosphoric acid/tri-n-octyl phosphine oxide) in Kerosene. The extract is then washed and uranium is backextracted and precipitated as commercial concentrate. The organic phase is recovered. Results from discontinuous tests were satisfactory, enabling to establish operational conditions for the performance of a continuous test in a micro-pilot plant. (Author) [pt

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

Uranium uptake by hydroponically cultivated crop plants

Energy Technology Data Exchange (ETDEWEB)

Soudek, Petr; Petrova, Sarka [Laboratory of Plant Biotechnologies, Joint Laboratory of Institute of Experimental Botany AS CR, v.v.i. and Crop Research Institute, v.v.i., Rozvojova 263, 162 05 Prague 6 (Czech Republic); Benesova, Dagmar [Laboratory of Plant Biotechnologies, Joint Laboratory of Institute of Experimental Botany AS CR, v.v.i. and Crop Research Institute, v.v.i., Rozvojova 263, 162 05 Prague 6 (Czech Republic); Faculty of Environment Technology, Institute of Chemical Technology, Technicka 5, 166 28 Prague 6 (Czech Republic); Dvorakova, Marcela [Laboratory of Plant Biotechnologies, Joint Laboratory of Institute of Experimental Botany AS CR, v.v.i. and Crop Research Institute, v.v.i., Rozvojova 263, 162 05 Prague 6 (Czech Republic); Vanek, Tomas, E-mail: vanek@ueb.cas.cz [Laboratory of Plant Biotechnologies, Joint Laboratory of Institute of Experimental Botany AS CR, v.v.i. and Crop Research Institute, v.v.i., Rozvojova 263, 162 05 Prague 6 (Czech Republic)

2011-06-15

Hydroponicaly cultivated plants were grown on medium containing uranium. The appropriate concentrations of uranium for the experiments were selected on the basis of a standard ecotoxicity test. The most sensitive plant species was determined to be Lactuca sativa with an EC{sub 50} value about 0.1 mM. Cucumis sativa represented the most resistant plant to uranium (EC{sub 50} = 0.71 mM). Therefore, we used the uranium in a concentration range from 0.1 to 1 mM. Twenty different plant species were tested in hydroponic solution supplemented by 0.1 mM or 0.5 mM uranium concentration. The uranium accumulation of these plants varied from 0.16 mg/g DW to 0.011 mg/g DW. The highest uranium uptake was determined for Zea mays and the lowest for Arabidopsis thaliana. The amount of accumulated uranium was strongly influenced by uranium concentration in the cultivation medium. Autoradiography showed that uranium is mainly localized in the root system of the plants tested. Additional experiments demonstrated the possibility of influencing the uranium uptake from the cultivation medium by amendments. Tartaric acid was able to increase uranium uptake by Brassica oleracea and Sinapis alba up to 2.8 times or 1.9 times, respectively. Phosphate deficiency increased uranium uptake up to 4.5 times or 3.9 times, respectively, by Brassica oleracea and S. alba. In the case of deficiency of iron or presence of cadmium ions we did not find any increase in uranium accumulation. - Highlights: > The uranium accumulation in twenty different plant species varied from 0.160 to 0.011 mg/g DW. > Uranium is mainly localized in the root system. > Tartaric acid was able to increase uranium uptake by Brassica oleracea and Sinapis alba. > The phosphates deficiency increase the uranium uptake.

Uranium uptake by hydroponically cultivated crop plants

International Nuclear Information System (INIS)

Soudek, Petr; Petrova, Sarka; Benesova, Dagmar; Dvorakova, Marcela; Vanek, Tomas

2011-01-01

Hydroponicaly cultivated plants were grown on medium containing uranium. The appropriate concentrations of uranium for the experiments were selected on the basis of a standard ecotoxicity test. The most sensitive plant species was determined to be Lactuca sativa with an EC 50 value about 0.1 mM. Cucumis sativa represented the most resistant plant to uranium (EC 50 = 0.71 mM). Therefore, we used the uranium in a concentration range from 0.1 to 1 mM. Twenty different plant species were tested in hydroponic solution supplemented by 0.1 mM or 0.5 mM uranium concentration. The uranium accumulation of these plants varied from 0.16 mg/g DW to 0.011 mg/g DW. The highest uranium uptake was determined for Zea mays and the lowest for Arabidopsis thaliana. The amount of accumulated uranium was strongly influenced by uranium concentration in the cultivation medium. Autoradiography showed that uranium is mainly localized in the root system of the plants tested. Additional experiments demonstrated the possibility of influencing the uranium uptake from the cultivation medium by amendments. Tartaric acid was able to increase uranium uptake by Brassica oleracea and Sinapis alba up to 2.8 times or 1.9 times, respectively. Phosphate deficiency increased uranium uptake up to 4.5 times or 3.9 times, respectively, by Brassica oleracea and S. alba. In the case of deficiency of iron or presence of cadmium ions we did not find any increase in uranium accumulation. - Highlights: → The uranium accumulation in twenty different plant species varied from 0.160 to 0.011 mg/g DW. → Uranium is mainly localized in the root system. → Tartaric acid was able to increase uranium uptake by Brassica oleracea and Sinapis alba. → The phosphates deficiency increase the uranium uptake.

Uranium 2007: resources, production and demand

International Nuclear Information System (INIS)

2008-01-01

With several countries building nuclear power plants and many more considering the use of nuclear power to produce electricity in order to meet rising demand, the uranium industry has become the focus of considerable attention. In response to rising demand and declining inventories, uranium prices have increased dramatically in recent years. As a result, the uranium industry is undergoing a significant revival, bringing to an end a period of over 20 years of under investment. The ''Red Book'', jointly prepared by the OECD Nuclear Energy Agency and the International Atomic Energy Agency, is a recognised world reference on uranium. It is based on official information received from 40 countries. This 22. edition provides a comprehensive review of world uranium supply and demand as of 1. January 2007, as well as data on global uranium exploration, resources, production and reactor-related requirements. It provides substantive new information from 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 2030 are also featured, along with an analysis of long-term uranium supply and demand issues. (author)

Uranium 2007: resources, production and demand

International Nuclear Information System (INIS)

2008-01-01

With several countries building nuclear power plants and many more considering the use of nuclear power to produce electricity in order to meet rising demand, the uranium industry has become the focus of considerable attention. In response to rising demand and declining inventories, uranium prices have increased dramatically in recent years. As a result, the uranium industry is undergoing a significant revival, bringing to an end a period of over 20 years of under investment. The ''Red Book'', jointly prepared by the OECD Nuclear Energy Agency and the International Atomic Energy Agency, is a recognised world reference on uranium. It is based on official information received from 40 countries. This second edition provides a comprehensive review of world uranium supply and demand as of first January 2007, as well as data on global uranium exploration, resources, production and reactor-related requirements. It provides substantive new information from 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 2030 are also featured, along with an analysis of long-term uranium supply and demand issues. (author)

Sedimentary rocks Uranium in Cerro Largo Province

International Nuclear Information System (INIS)

Scaron, P.; Garau Tous, M.

1976-01-01

With the aim of the uranium minerals exploration has been carried out several studies by UTE technicians in Cerro Largo Province from 1968 to 1969. In uranium concentration has been found pyrite, phosphate, iron oxides and manganese in uranium. Furthermore in La Divisa Ore were studied concentration Uranium enrichment has been studied in La Divisa ore

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

Uranium industry annual 1996

International Nuclear Information System (INIS)

1997-04-01

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

Uranium industry annual 1996

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-04-01

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

Uranium industry annual, 1986

International Nuclear Information System (INIS)

1987-01-01

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

Uranium industry annual 1985

International Nuclear Information System (INIS)

1986-11-01

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

Uranium 2009 resources, production and demand

CERN Document Server

Organisation for Economic Cooperation and Development. Paris

2010-01-01

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

Concentration and characteristics of depleted uranium in water, air and biological samples collected in Serbia and Montenegro

International Nuclear Information System (INIS)

Jia Guogang; Belli, Maria; Sansone, Umberto; Rosamilia, Silvia; Gaudino, Stefania

2005-01-01

During the Balkan conflicts, in 1995 and 1999, depleted uranium (DU) rounds were employed and were left in the battlefield. Health concern is related to the risk arising from contamination of the environment with DU penetrators and dust. In order to evaluate the impact of DU on the environment and population in Serbia and Montenegro, radiological surveys of DU in water, air and biological samples were carried out over the period 27 October-5 November 2001. The uranium isotopic concentrations in biological samples collected in Serbia and Montenegro, mainly lichens and barks, were found to be in the range of 0.67-704 Bq kg -1 for 238 U, 0.48-93.9 Bq kg -1 for 234 U and 0.02-12.2 Bq kg -1 for 235 U, showing uranium levels to be higher than in the samples collected at the control sites. Moreover, 236 U was detectable in some of the samples. The isotopic ratios of 234 U/ 238 U showed DU to be detectable in many biological samples at all examined sites, especially in Montenegro, indicating widespread ground-surface DU contamination, albeit at very low level. The uranium isotopic concentrations in air obtained from the air filter samples collected in Serbia and Montenegro were found to be in the range of 1.99-42.1 μBq m -3 for 238 U, 0.96-38.0 μBq m -3 for 234 U, and 0.05-1.83 μBq m -3 for 235 U, being in the typical range of natural uranium values. Thus said, most of the air samples are DU positive, this fact agreeing well with the widespread DU contamination detected in the biological samples. The uranium concentrations in water samples collected in Serbia and Montenegro were found to be in the range of 0.40-21.9 mBq l -1 for 238 U, 0.27-28.1 mBq l -1 for 234 U, and 0.01-0.88 mBq l -1 for 235 U, these values being much lower than those in mineral water found in central Italy and below the WHO guideline for drinking water. From a radiotoxicological point of view, at this moment there is no significant radiological risk related to these investigated sites in terms of

Concentration and characteristics of depleted uranium in water, air and biological samples collected in Serbia and Montenegro.

Science.gov (United States)

Jia, Guogang; Belli, Maria; Sansone, Umberto; Rosamilia, Silvia; Gaudino, Stefania

2005-09-01

During the Balkan conflicts, in 1995 and 1999, depleted uranium (DU) rounds were employed and were left in the battlefield. Health concern is related to the risk arising from contamination of the environment with DU penetrators and dust. In order to evaluate the impact of DU on the environment and population in Serbia and Montenegro, radiological surveys of DU in water, air and biological samples were carried out over the period 27 October-5 November 2001. The uranium isotopic concentrations in biological samples collected in Serbia and Montenegro, mainly lichens and barks, were found to be in the range of 0.67-704 Bqkg(-1) for (238)U, 0.48-93.9 Bqkg(-1) for (234)U and 0.02-12.2 Bqkg(-1) for (235)U, showing uranium levels to be higher than in the samples collected at the control sites. Moreover, (236)U was detectable in some of the samples. The isotopic ratios of (234)U/(238)U showed DU to be detectable in many biological samples at all examined sites, especially in Montenegro, indicating widespread ground-surface DU contamination, albeit at very low level. The uranium isotopic concentrations in air obtained from the air filter samples collected in Serbia and Montenegro were found to be in the range of 1.99-42.1 microBqm(-3) for (238)U, 0.96-38.0 microBqm(-3) for (234)U, and 0.05-1.83 microBqm(-3) for (235)U, being in the typical range of natural uranium values. Thus said, most of the air samples are DU positive, this fact agreeing well with the widespread DU contamination detected in the biological samples. The uranium concentrations in water samples collected in Serbia and Montenegro were found to be in the range of 0.40-21.9 mBql(-1) for (238)U, 0.27-28.1 mBql(-1) for (234)U, and 0.01-0.88 mBql(-1) for (235)U, these values being much lower than those in mineral water found in central Italy and below the WHO guideline for drinking water. From a radiotoxicological point of view, at this moment there is no significant radiological risk related to these investigated

Application of bimodal distribution to the detection of changes in uranium concentration in drinking water collected by random daytime sampling method from a large water supply zone.

Science.gov (United States)

Garboś, Sławomir; Święcicka, Dorota

2015-11-01

The random daytime (RDT) sampling method was used for the first time in the assessment of average weekly exposure to uranium through drinking water in a large water supply zone. Data set of uranium concentrations determined in 106 RDT samples collected in three runs from the water supply zone in Wroclaw (Poland), cannot be simply described by normal or log-normal distributions. Therefore, a numerical method designed for the detection and calculation of bimodal distribution was applied. The extracted two distributions containing data from the summer season of 2011 and the winter season of 2012 (nI=72) and from the summer season of 2013 (nII=34) allowed to estimate means of U concentrations in drinking water: 0.947 μg/L and 1.23 μg/L, respectively. As the removal efficiency of uranium during applied treatment process is negligible, the effect of increase in uranium concentration can be explained by higher U concentration in the surface-infiltration water used for the production of drinking water. During the summer season of 2013, heavy rains were observed in Lower Silesia region, causing floods over the territory of the entire region. Fluctuations in uranium concentrations in surface-infiltration water can be attributed to releases of uranium from specific sources - migration from phosphate fertilizers and leaching from mineral deposits. Thus, exposure to uranium through drinking water may increase during extreme rainfall events. The average chronic weekly intakes of uranium through drinking water, estimated on the basis of central values of the extracted normal distributions, accounted for 3.2% and 4.1% of tolerable weekly intake. Copyright © 2015 Elsevier Ltd. All rights reserved.

Canadian resources of uranium and thorium

International Nuclear Information System (INIS)

Griffith, J.W.; Roscoe, S.M.

1964-01-01

Canada has been one of the world's leading producers of uranium since the metal became important as a raw material in the development and production of atomic energy. One of the largest known deposits in the world is in Canada where present reserves represent about 37 per cent of the total among those countries that have published reserve statistics. The production of uranium has been characterized by features which are unique in Canadian mining, because the industry was created by the government at a time of emergency and, unlike other minerals, the sale of its product is controlled by the state. The rapid growth of the uranium-mining industry since World War II has been a remarkable achievement. In 1958, Canada was the world's leading producer of uranium and the value of U 3 O 8 produced in both 1958 and 1959 exceeded the value of any other Canadian-produced metal. As an export commodity, uranium ranked fourth in value in 1959 following newsprint, wheat, and lumber. Production from 25 mines in that year was 14 462 tonnes of U 3 O 8 valued at $345 million (all monetary values are in U.S. dollars). Since 1959, however, the decline in production, resulting from declining export markets, has been almost as rapid as the spectacular rise from 1953 to 1959. At the end of 1963 only seven mines were in production and by the end of 1965 only two mines are expected to remain in operation. (author)

Uranium hydrogeochemical and stream sediment reconnaissance of the Bozeman NTMS quadrangle, Montana, including concentrations of forty-two additional elements

International Nuclear Information System (INIS)

Bolivar, S.L.; Hensley, W.K.; Van Haaften, I.J.; Pirtle, J.; George, W.E.; Gallimore, D.; Apel, C.; Hansel, J.

1980-07-01

This report contains uranium analyses for 1251 water samples and multielement analyses for 1536 sediment samples. Sediments were analyzed for uranium and thorium as well as aluminum, antimony, barium, beryllium, bismuth, cadmium, calcium, cerium, cesium, chlorine, chromium, cobalt, copper, dysprosium, europium, gold, hafnium, iron, lanthanum, lead, lithium, lutetium, magnesium, manganese, nickel, niobium, potassium, rubidium, samarium, scandium, silver, sodium, strontium, tantalum, terbium, tin, titanium, tungsten, vanadium, ytterbium, and zinc. Water samples were initially analyzed for uranium by fluorometry. All water samples containing more than 40 ppB uranium were reanalyzed by delayed-neutron counting (DNC). All sediments were analyzed for uranium by DNC. Other elemental concentrations in sediments were determined by neutron activation analysis for 31 elements, by x-ray fluorescence for 9 elements, and by arc-source emission spectrography for 2 elements. Analytical results for sediments are reported as parts per million. Descriptions of procedures used for analysis of water and sediment samples as well as analytical precisions and detection limits are given

Declines in the dissolved organic carbon (DOC) concentration and flux from the UK

Science.gov (United States)

Worrall, Fred; Howden, Nicholas J. K.; Burt, Tim P.; Bartlett, Rebecca

2018-01-01

Increased concentrations of dissolved organic carbon (DOC) have been reported for many catchments across the northern hemisphere. Hypotheses to explain the increase have varied (eg. increasing air temperature or recovery from acidification) but one test of alternative hypotheses is the trend over the recent decade, with the competing hypotheses predicting: continuing increase; the rate of increase declining with time; and even decrease in concentration. In this study, records of DOC concentration in non-tidal rivers across the UK were examined for the period 2003-2012. The study found that: Of the 62 decade-long concentration trends that could be examined, 3 showed a significant increase, 17 experienced no significant change and 42 showed a significant decrease; in 28 of the 42 significant decreases, a significant step change was apparent with step changes being a decrease in concentration in every case. Of the 118 sites where annual flux and concentration records were available from 1974, 28 showed a significant step change down in flux and 52 showed a step down in concentration. The modal year of the step changes was 2000 with no step changes observed before 1982. At the UK national scale, DOC flux peaked in 2005 at 1354 ktonnes C/yr (5.55 tonnes C/km2/yr) but has declined since. The study suggests that there is a disconnection between DOC records from large catchments at their tidal limits and complementary records from headwater catchments, which means that mechanisms believed to be driving increases in DOC concentrations in headwaters will not necessarily be those controlling trends in DOC concentration further downstream. We propose that the changes identified here have been driven by changes in in-stream processing and changes brought about by the Urban Waste Water Treatment Directive. Therefore, signals identified in headwater catchments may bear little relation to those observed in large rivers much further downstream and vice versa.

Optimization of Davies and Gray/NBL method used for determination of total uranium concentration in the safeguards destructive analysis

Energy Technology Data Exchange (ETDEWEB)

Silva, Jose Wanderley S. da; Viana, Aline Gonzalez; Barros, Pedro Dionisio de; Cristiano, Barbara Fernandes G., E-mail: wanderley@ird.gov.br, E-mail: agonzalez@ird.gov.br, E-mail: pedrodio@ird.gov.br, E-mail: barbara@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

2013-07-01

One important activity conducted by the Brazilian State System of Accounting for and Control of Nuclear Materials - SSAC is to verify inventories of the nuclear facilities by nondestructive analysis and destructive analysis. For destructive analysis, the Safeguards Laboratory of Brazilian Nuclear Energy Commission - LASAL/CNEN has been applying the 'Davies and Gray/NBL' method in samples taken during inspections at nuclear facilities since 1984 in Brazil and Argentina. This method consists of the determination of total uranium concentration by potentiometric titration of uranium (IV) with a standard solution of potassium dichromate as oxidizing agent. This solution is prepared using a K{sub 2}Cr{sub 2}O{sub 7} SRM 136e standard reference material (99.984 ±0.010) wt% certified by National Institute of Standard and Technology - NIST. The procedure also includes the calibration with primary uranium standards reference material (NBL CRM 112A). In order to reduce the consumption of K{sub 2}Cr{sub 2}O{sub 7} and the other reagent involved in the procedure, without any loss in the performance of the method, a K{sub 2}Cr{sub 2}O{sub 7} solution with half the regular concentration was prepared and used to test the uranium concentration in several aliquots with a content between 30 mg to 40 mg of uranium per gram of solution. After optimizing the parameters and procedure, it was possible to get the same performance as well. As a consequence, decreasing of the cost, the amount of waste and also a reduction in the titration time of each aliquot was achieved. Thus, this work describes all details in this research as well as the results and its evaluation. (author)

Uranium-238 and thorium-232 series concentrations in soil, radon-222 indoor and drinking water concentrations and dose assessment in the city of Alameda, Chihuahua, Mexico

Energy Technology Data Exchange (ETDEWEB)

Colmenero Sujo, L.; Montero Cabrera, M.E. E-mail: elena.montero@cimav.edu.mx; Villalba, L.; Renteria Villalobos, M.; Torres Moye, E.; Garcia Leon, M.; Garcia-Tenorio, R.; Mireles Garcia, F.; Herrera Peraza, E.F.; Sanchez Aroche, D

2004-07-01

High-resolution gamma spectrometry was used to determine the concentration of {sup 40}K, {sup 238}U and {sup 232}Th series in soil samples taken from areas surrounding the city of Aldama, in Chihuahua. Results of indoor air short-time sampling, with diffusion barrier charcoal detectors, revealed relatively high indoor radon levels, ranging from 29 to 422 Bq/m{sup 3}; the radon concentrations detected exceeded 148 Bq/m{sup 3} in 76% of the homes tested. Additionally, liquid scintillation counting showed concentrations of radon in drinking water ranging from 4.3 to 42 kBq/m{sup 3}. The high activity of {sup 238}U in soil found in some places may be a result of the uranium milling process performed 20 years ago in the area. High radon concentrations indoor and in water may be explained by assuming the presence of uranium-bearing rocks underneath of the city, similar to a felsic dike located near Aldama. The estimated annual effective dose of gamma radiation from the soil and radon inhalation was 3.83 mSv.

Uranium-238 and thorium-232 series concentrations in soil, radon-222 indoor and drinking water concentrations and dose assessment in the city of Aldama, Chihuahua, Mexico.

Science.gov (United States)

Colmenero Sujo, L; Montero Cabrera, M E; Villalba, L; Rentería Villalobos, M; Torres Moye, E; García León, M; García-Tenorio, R; Mireles García, F; Herrera Peraza, E F; Sánchez Aroche, D

2004-01-01

High-resolution gamma spectrometry was used to determine the concentration of 40K, 238U and 232Th series in soil samples taken from areas surrounding the city of Aldama, in Chihuahua. Results of indoor air short-time sampling, with diffusion barrier charcoal detectors, revealed relatively high indoor radon levels, ranging from 29 to 422 Bq/m3; the radon concentrations detected exceeded 148 Bq/m3 in 76% of the homes tested. Additionally, liquid scintillation counting showed concentrations of radon in drinking water ranging from 4.3 to 42 kBq/m3. The high activity of 238U in soil found in some places may be a result of the uranium milling process performed 20 years ago in the area. High radon concentrations indoor and in water may be explained by assuming the presence of uranium-bearing rocks underneath of the city, similar to a felsic dike located near Aldama. The estimated annual effective dose of gamma radiation from the soil and radon inhalation was 3.83 mSv.

Uranium concentrations in natural waters, South Park, Colorado

International Nuclear Information System (INIS)

Sharp, R.R. Jr.; Aamodt, P.L.

1976-08-01

During the summer of 1975, 464 water samples from 149 locations in South Park, Colorado, were taken for the Los Alamos Scientific Laboratory in order to test the field sampling and analytical methodologies proposed for the NURE Hydrogeochemical and Stream Sediment Reconnaissance for uranium in the Rocky Mountain states and Alaska. The study showed, in the South Park area, that the analytical results do not vary significantly between samples which were untreated, filtered and acidified, filtered only, or acidified only. Furthermore, the analytical methods of fluorometry and delayed-neutron counting, as developed at the LASL for the reconnaissance work, provide fast, adequately precise, and complementary procedures for analyzing a broad range of uranium in natural waters. The data generated using this methodology does appear to identify uraniferous areas, and when applied using sound geochemical, geological, and hydrological principles, should prove a valuable tool in reconnaissance surveying to delineate new districts or areas of interest for uranium exploration

Simultaneous determination of nitric acid and uranium concentrations in aqueous solution from measurements of electrical conductivity, density, and temperature

International Nuclear Information System (INIS)

Spencer, B.B.

1991-01-01

Nuclear fuel reprocessing plants handle aqueous solutions of nitric acid and uranium in large quantities. Automatic control of process operations requires reliable measurements of these solutes concentration, but this is difficult to directly measure. Physical properties such as solution density and electrical conductivity vary with solute concentration and temperature. Conductivity, density and temperature can be measured accurately with relatively simple and inexpensive devices. These properties can be used to determine solute concentrations will good correlations. This paper provides the appropriate correlations for solutions containing 2 to 6 Molar (M) nitric acid and 0 to 300 g/L uranium metal at temperatures from 25--90 degrees C. The equations are most accurate below 5 M nitric acid, due to a broad maximum in the conductivity curve at 6 M. 12 refs., 9 figs., 6 tabs

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

International Nuclear Information System (INIS)

Zhang Jindai; Xu Gaozhong; Chen Anping; Wang Cheng

2005-01-01

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

Uranium isotopes in ground water as a prospecting technique

International Nuclear Information System (INIS)

Cowart, J.B.; Osmond, J.K.

1980-02-01

The isotopic concentrations of dissolved uranium were determined for 300 ground water samples near eight known uranium accumulations to see if new approaches to prospecting could be developed. It is concluded that a plot of 234 U/ 238 U activity ratio (A.R.) versus uranium concentration (C) can be used to identify redox fronts, to locate uranium accumulations, and to determine whether such accumulations are being augmented or depleted by contemporary aquifer/ground water conditions. In aquifers exhibiting flow-through hydrologic systems, up-dip ground water samples are characterized by high uranium concentration values (> 1 to 4 ppB) and down-dip samples by low uranium concentration values (less than 1 ppB). The boundary between these two regimes can usually be identified as a redox front on the basis of regional water chemistry and known uranium accumulations. Close proximity to uranium accumulations is usually indicated either by very high uranium concentrations in the ground water or by a combination of high concentration and high activity ratio values. Ground waters down-dip from such accumulations often exhibit low uranium concentration values but retain their high A.R. values. This serves as a regional indicator of possible uranium accumulations where conditions favor the continued augmentation of the deposit by precipitation from ground water. Where the accumulation is being dispersed and depleted by the ground water system, low A.R. values are observed. Results from the Gulf Coast District of Texas and the Wyoming districts are presented

Uranium hydrogeochemical and stream sediment reconnasissance of the Trinidad NTMS Quadrangle, Colorado, including concentrations of forty-two additional elements

International Nuclear Information System (INIS)

Shannon, S.S. Jr.

1980-05-01

Uranium and other elemental data resulting from the Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) of the Trinidad National Topographic Map Series (NTMS) quadrangle, Colorado, by the Los Alamos Scientific Laboratory (LASL) are reported herein. This study was conducted as part of the United States Department of Energy's National Uranium Resource Evaluation (NURE), which is designed to provide improved estimates of the availability and economics of nuclear fuel resources and to make available to industry information for use in exploration and development of uranium resources. The HSSR data will ultimately be integrated with other NURE data (e.g., airborne radiometric surveys and geological investigations) to complete the entire NURE program. This report is a supplement to the HSSR uranium evaluation report for the Trinidad quadrange (Morris et al, 1978), which presented the field and uranium data for the 1060 water and 1240 sediment samples collected from 1768 locations in the quadrangle. The earlier report contains an evaluation of the uranium concentrations of the samples as well as descriptions of the geology, hydrology, climate, and uranium occurrences of the quadrange. This supplement presents the sediment field and uranium data again and the analyses of 42 other elements in the sediments. All uranium samples were redetermined by delayed-neutron counting (DNC) when the sediment samples were analyzed for 31 elements by neutron activation. For 99.6% of the sediment samples analyzed, the differences between the uranium contents first determined (Morris et al, 1978) and the analyses reported herein are less than 10%

Uranium, Thorium and Potassium concentrations and volumetric heat production rates at the eastern border of the Parana basin

International Nuclear Information System (INIS)

Andrade, Telma C.Q.; Ribeiro, Fernando B.

1997-01-01

Uranium, thorium and potassium concentrations were measured and volumetric heat production rates were calculated for rocks from the exposed basement at the eastern-southeastern border of the Parana Basin between 23 deg S and 32 deg S. Heat generating element concentration data available in the literature were also used when possible, for volumetric heat production calculations. The uranium concentrations vary from below determination limit (0.51 ppm) and 16 ppm whereas the thorium concentrations vary from below the determination limit (1.26 ppm) and 68 ppm, and K concentrations vary between 0.08% and 5.6%. Volumetric heat production rates vary between 0.07 μW/m 3 to 6.2 μW/m 3 , and the obtained results show a variable heat generation rate with high heat producing bodies scattered along this Parana Basin border. The higher observed values concentrate in the Ribeira fold belt at about 23 deg S and between 30 deg S and 32 deg S in the Down Feliciano fold belt. Isolated high heat production rates can also be observed between 26 deg S and 28 deg S. (author). 11 refs., 3 tabs

Elevated Uranium in Aquifers of the Jacobsville Sandstone

Science.gov (United States)

Sherman, H.; Gierke, J.

2003-12-01

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

Assessment of the total uranium concentration in surface and underground water samples from the Caetite region, Bahia, Brazil

International Nuclear Information System (INIS)

Silva, Julia Grasiela Batista; Geraldo, Luiz Paulo; Yamazaki, Ione Makiko

2011-01-01

At the region of Caetite, BA, it is located the largest uranium mine in exploration at present days in Brazil. During the uranium extraction process, it may be having an environmental contamination by this heavy metal due to rain water and other natural transport mechanism, with potential exposition risk to the local population. The aim of this work was to investigate the total uranium concentration in surface and underground water samples collected at the Caetite region, using the nuclear track registration technique (SSNTD) in a polycarbonate plastic. A 100 mL volume of water samples were initially treated in 10 mL of HNO 3 (PA) and concentrated by evaporation at a temperature around 80 deg C. The resulting residue was diluted to a total volume of 25 mL without pass it to a filter. About 10 μL of this solution was deposited on the plastic detector surface (around 1.0 cm 2 area) together with 5 μL of a Cyastat detergent solution (5%) and evaporated under an infrared lamp. All the resulting deposits of non volatile constituents were irradiated, together with a uranium standard sample, at the IPEN-IEA-R1 (3.5 MW) nuclear reactor for approximately 3 min. After irradiations, chemical etching of the plastic detectors was carried out at 60 deg C, for 65 min. in a NaOH (6N) solution. The fission tracks were counted scanning all the deposit area of the polycarbonate plastic detector with a system consisting of an optical microscope together with a video camera and TV monitor. The average values of uranium concentrations obtained in this work ranged from (0.95±0.19) μg.L -1 to (25.60±3.3) μg.L -1 . These results were compared to values reported in the literature for water samples from other regions and discussed in terms of safe limits recommended by WHO -World Health Organization and CONAMA - Conselho Nacional do Meio Ambiente. (author)

Assessment of the total uranium concentration in surface and underground water samples from the Caetite region, Bahia, Brazil

Energy Technology Data Exchange (ETDEWEB)

Silva, Julia Grasiela Batista; Geraldo, Luiz Paulo [Centro Universitario da Fundacao Educacional de Barretos (UNIFEB), (SP) (Brazil); Yamazaki, Ione Makiko [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2011-07-01

At the region of Caetite, BA, it is located the largest uranium mine in exploration at present days in Brazil. During the uranium extraction process, it may be having an environmental contamination by this heavy metal due to rain water and other natural transport mechanism, with potential exposition risk to the local population. The aim of this work was to investigate the total uranium concentration in surface and underground water samples collected at the Caetite region, using the nuclear track registration technique (SSNTD) in a polycarbonate plastic. A 100 mL volume of water samples were initially treated in 10 mL of HNO{sub 3} (PA) and concentrated by evaporation at a temperature around 80 deg C. The resulting residue was diluted to a total volume of 25 mL without pass it to a filter. About 10 {mu}L of this solution was deposited on the plastic detector surface (around 1.0 cm{sup 2} area) together with 5 {mu}L of a Cyastat detergent solution (5%) and evaporated under an infrared lamp. All the resulting deposits of non volatile constituents were irradiated, together with a uranium standard sample, at the IPEN-IEA-R1 (3.5 MW) nuclear reactor for approximately 3 min. After irradiations, chemical etching of the plastic detectors was carried out at 60 deg C, for 65 min. in a NaOH (6N) solution. The fission tracks were counted scanning all the deposit area of the polycarbonate plastic detector with a system consisting of an optical microscope together with a video camera and TV monitor. The average values of uranium concentrations obtained in this work ranged from (0.95{+-}0.19) {mu}g.L{sup -1} to (25.60{+-}3.3) {mu}g.L{sup -1}. These results were compared to values reported in the literature for water samples from other regions and discussed in terms of safe limits recommended by WHO -World Health Organization and CONAMA - Conselho Nacional do Meio Ambiente. (author)

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)

Uranium 2016: Resources, Production and Demand

International Nuclear Information System (INIS)

2016-01-01

Uranium is the raw material used to produce fuel for long-lived nuclear power facilities, necessary for the generation of significant amounts of base-load low-carbon electricity for decades to come. Although a valuable commodity, declining market prices for uranium in recent years, driven by uncertainties concerning evolutions in the use of nuclear power, have led to the postponement of mine development plans in a number of countries and to some questions being raised about future uranium supply. This 26. edition of the 'Red Book', a recognised world reference on uranium jointly prepared by the Nuclear Energy Agency (NEA) and the International Atomic Energy Agency (IAEA), provides analyses and information from 49 producing and consuming countries in order to address these and other questions. The present edition provides the most recent review of world uranium market fundamentals and presents data on global uranium exploration, resources, production and reactor-related requirements. It offers updated information on established uranium production centres and mine development plans, as well as projections of nuclear generating capacity and reactor-related requirements through 2035, in order to address long-term uranium supply and demand issues. (authors)

Technology for down-blending weapons grade uranium into commercial reactor-usable uranium

International Nuclear Information System (INIS)

Arbital, J.G.; Snider, J.D.

1996-01-01

The US Department of Energy (DOE) is evaluating options for rendering surplus inventories of highly enriched uranium (HEU) incapable of being used in nuclear weapons. Weapons-capable HEU was earlier produced by enriching the uranium isotope 235 U from its natural occurring 0.71 percent isotopic concentration to at least 20 percent isotopic concentration. Now, by permanently diluting the concentration of the 235 U isotope, the weapons capability of HEU can be eliminated in a manner that is reversible only through isotope re-enrichment, and therefore, highly resistant to proliferation. To the extent that can be economically and technically justified, the down-blended, low-enriched uranium product will be made suitable for use as commercial reactor fuel. Such down-blended uranium product can also be disposed of as waste if chemical or isotopic impurities preclude its use as reactor fuel. The DOE has evaluated three candidate processes for down blending surplus HEU. These candidate processes are: (1) uranium hexafluoride blending; (2) molten uranium metal blending; and (3) uranyl nitrate solution blending. This paper describes each of these candidate processes. It also compares the relative advantages and disadvantages of each process with respect to: (1) the various forms and compounds of HEU comprising the surplus inventory, (2) the use of down-blended product as commercial reactor fuel, or (3) its disposal as waste

On the anomalous concentrations of uranium in sediments from hydrothermal mounds. A geochemical roll-type mechanism

International Nuclear Information System (INIS)

Bernat, M.; Benhassaine, A.

1987-01-01

Sediments close to the nontronite formations of hydrothermal mounds often show anomalously high concentrations of uranium. This is frequently interpreted as being due to seeping of low temperature U bearing hydrothermal water through the basal basalt and into the overlying sediments. But we think that this phenomenon is the consequence of leaching of the sediment by hydrothermal water initially depleted in uranium. The migration of U is favoured by the pH of these water which dissolve the iron oxides and hydroxides giving Fe +++ ions in solution. The location and strength of the formed U anomalies are controlled by geochemical and hydrodynamicals factors. 22 refs [fr

Sandstone-type uranium deposits

International Nuclear Information System (INIS)

Finch, W.I.; Davis, J.F.

1985-01-01

World-class sandstone-type uranium deposits are defined as epigenetic concentrations of uranium minerals occurring as uneven impregnations and minor massive replacements primarily in fluvial, lacustrine, and deltaic sandstone formations. The main purpose of this introductory paper is to define, classify, and introduce to the general geologic setting for sandstone-type uranium deposits

Uranium determination in dental ceramics

International Nuclear Information System (INIS)

Jacobson, I.; Gamboa, I.; Espinosa, G.; Moreno, A.

1984-01-01

There are many reports of high uranium concentration in dental ceramics, so they require to be controlled. The SSNTD is an optional method to determine the uranium concentration. In this work the analysis of several commercial dental ceramics used regularly in Mexico by dentists is presented. The chemical and electrochemical processes are used and the optimal conditions for high sensitivity are determined. CR-39 (allyl diglycol polycarbonate) was used as detector. The preliminary results show some materials with high uranium concentrations. Next step will be the analysis of equivalent dose and the effects in the public health. (author)

Code of Practice on radiation protection in the mining and milling of radioactive ores (1980) - Guidelines for storage and packaging of uranium concentrates

International Nuclear Information System (INIS)

1986-01-01

This Guideline is intended to provide assistance in the application of the 1980 Code of Practice on radiation protection in mining and milling of radioactive ores. Its purpose is to give advice relevant to the design, construction and operation of an uranium concentrate storage and packaging facility in which exposure to ionizing radiation from uranium-bearing concentrate will not only conform to the Code, but will also be as low as reasonably achievable. (NEA) [fr

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.'

The U.S. uranium industry

International Nuclear Information System (INIS)

Glasier, G.E.

1987-01-01

This presentation concentrates on the future of the U.S. uranium industry in light of potential embargo legislation and the uranium producers' lawsuit. The author discusses several possible resolutions which would lead to a more certain and possibly stable uranium market. The probability of one or more Six possible actions which would effect the uranium industry are addressed

Quantum dots as a probe to detect uranium

International Nuclear Information System (INIS)

Singhal, Pallavi; Jha, S.K.; Tripathi, R.M.

2016-01-01

Uranium is one of the most toxic heavy metals. A number of methods have been developed to detect uranium at lower concentrations. Here in we proposed a method which can sense the presence of uranium in nm-μM concentration range. We have synthesized CdSe and CdSe/CdS core shell quantum dots with different thickness of CdS shell and monitor their luminescence property in presence of uranium. Interestingly a quenching in QDs luminescence was observed on addition of uranium in uM concentrations. We have also carried out time resolved studies which suggests faster luminescence decay on addition of uranium. Both time resolved studies and energetic suggest that electron transfer from QDs to uranium is favourable and quenching in luminescence is due to electron transfer from QD to uranium and is found to be different with different thickness of CdS shell. The results presented reveal the promising potential of QDs for their use as chemical sensors to detect uranium. (author)

RA-226 concentration in water samples near uranium mines and in marine fishes

International Nuclear Information System (INIS)

Porntepkasemsan, B.

1987-11-01

Radium-226 and calcium were measured in water samples from the vicinity of three uranium mines and in fish samples collected from Puget sound, Washington State. The radium content of the samples were below the maximum permissible concentration 3 pCi/L for drinking water recommended by the Public Health Service and U.S. Environmental Protection Agency. The mean value of Ra-226 in water was 0.428 pCi/L and ranged from 0.043 to 1.552 pCi/L, whereas calcium content ranged from 3.0 to 190.0 mg/L. Ra-226 concentrations and calcium content in whole fish were 0.833-20.328 pCi/kg wet wt. and 114.1-259.3 mg/g ash, respectively. Results of the study indicated that Ra-226 concentration in water was correlated with calcium concentration but that this correlation was not observed in fish sample except English sole

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.)

Uranium's effects on bone integrity

International Nuclear Information System (INIS)

Souidi, Maamar; Wade-Gueye, Ndeye Marieme; Manens, Line; Blanchardon, Eric; Aigueperse, Jocelyne

2018-01-01

Uranium is a radioactive heavy metal naturally present in the environment. Its recent use in various civilian and military applications sometimes result in its release into the environment. After chronic ingestion, uranium accumulates in various organs, preferentially in bones. Several studies have shown that exposure to high concentrations of uranium affects bone growth. Little is known, however, about the effects of chronic exposure to low doses of uranium on bone, especially when ingested via drinking water, the main route by which the public is exposed to this radionuclide. This study examined the effects of chronic exposure to natural uranium through drinking water on bone integrity and bone turnover. Rats were contaminated with different concentrations of natural uranium (15, 10, and 40 mg / l) for 9 months. A high-resolution three-dimensional microtomography scanner was used for the first time to study uranium's impact on bone metabolism and thus on bone tissue integrity. After nine months of uranium exposure, micro-architecture analysis revealed that the cortical bone diameter of the femoral diaphysis of rats contaminated at a concentration of 40 mg/L of uranium had decreased significantly. In conclusion, our findings that chronic ingestion of uranium at low concentrations affects growth of cortical bone width suggests that it may affect bone strength. These results thus suggest the need to pay special attention to children during chronic low-dose exposure to this radionuclide. (authors)

Potential synergy between two renal toxicants: DTPA and uranium

International Nuclear Information System (INIS)

Muller, D.; Houpert, P.; Henge Napoli, M.H.; Paquet, F.; Muller, D.; Henge Napoli, M.H.; Metivier, H.

2006-01-01

At present, the most appropriate therapeutic approach to treat an accidental contamination with plutonium and uranium oxide mixture (MOX) is administration of diethylene-triamine-penta-acetate acid (DTPA) in order to accelerate plutonium excretion. As uranium and DTPA are both nephro-toxic compounds, the administration of DTPA after a contamination containing uranium could enhance the nephro-toxic effects of uranium. The aim of the present work was to study in vitro on a kidney proximal tubule cell line (LLC-PK 1 ) the cytotoxicity induced by increasing concentrations of uranium in presence of 3 different chemical forms of DTPA. The results showed that the DTPA used alone induced no cytotoxicity at the concentration used here (420 μM). However, this concentration of DTPA increased the cytotoxicity induced by uranium. This increase was maximal for uranium concentrations close to the lethal concentration for 50% of the cells and reached 37, 31 and 28% for anhydrous DTPA, Na 3 CaDTPA and Na 3 ZnDTPA, respectively. These results suggest that administration of DTPA could enhance the nephrotoxicity induced by uranium. (authors)

Canadian resources of uranium and thorium

Energy Technology Data Exchange (ETDEWEB)

Griffith, J W; Roscoe, S M [Dept. of Mines and Technical Surveys, Ottawa, Ontario (Canada)

1964-07-01

Canada has been one of the world's leading producers of uranium since the metal became important as a raw material in the development and production of atomic energy. One of the largest known deposits in the world is in Canada where present reserves represent about 37 per cent of the total among those countries that have published reserve statistics. The production of uranium has been characterized by features which are unique in Canadian mining, because the industry was created by the government at a time of emergency and, unlike other minerals, the sale of its product is controlled by the state. The rapid growth of the uranium-mining industry since World War II has been a remarkable achievement. In 1958, Canada was the world's leading producer of uranium and the value of U{sub 3}O{sub 8} produced in both 1958 and 1959 exceeded the value of any other Canadian-produced metal. As an export commodity, uranium ranked fourth in value in 1959 following newsprint, wheat, and lumber. Production from 25 mines in that year was 14 462 tonnes of U{sub 3}O{sub 8} valued at $345 million (all monetary values are in U.S. dollars). Since 1959, however, the decline in production, resulting from declining export markets, has been almost as rapid as the spectacular rise from 1953 to 1959. At the end of 1963 only seven mines were in production and by the end of 1965 only two mines are expected to remain in operation. (author)

Recovery of uranium from lignites

International Nuclear Information System (INIS)

Hurst, F.J.

1980-01-01

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

Uranium 2009: Resources, Production and Demand

International Nuclear Information System (INIS)

2010-01-01

With several countries currently building nuclear power plants and planning the construction of more to meet long-term increases in electricity demand, uranium resources, production and demand remain topics of notable interest. In response to the projected growth in demand for uranium and declining inventories, the uranium industry - the first critical link in the fuel supply chain for nuclear reactors - is boosting production and developing plans for further increases in the near future. Strong market conditions will, however, be necessary to trigger the investments required to meet projected demand. The 'Red Book', jointly prepared by the OECD Nuclear Energy Agency and the International Atomic Energy Agency, is a recognised world reference on uranium. It is based on information compiled in 40 countries, including those that are major producers and consumers of uranium. This 23. edition provides a comprehensive review of world uranium supply and demand as of 1 January 2009, as well as data on global uranium exploration, resources, production and reactor-related requirements. It provides substantive new information from major uranium production centres around the world, as well as from countries developing production centres for the first time. Projections of nuclear generating capacity and reactor-related uranium requirements through 2035 are also featured, along with an analysis of long-term uranium supply and demand issues

Uranium

International Nuclear Information System (INIS)

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

2010-01-01

concentration in peat bogs, deposits combined with marine phosphates, with coal and lignite, with black shales, with carbonate rocks, deposits in Precambrian quartz pebble conglomerates, basal-type deposits, deposits in sandstones (tabular, roll-type and tectono-lithologic deposits), breccia chimney filling deposits, deposits in metamorphic rocks, metasomatic deposits, deposits in intrusive rocks, deposits associated with hematite breccia complexes, deposits in granitic rocks, deposits in volcanic rocks, deposits in proterozoic discordances (Athabasca basin, Pine Creek geo-syncline); 4 - French uranium bearing areas and deposits: history of the French uranium mining industry, geological characteristics of French deposits (black shales, sandstones, granites), abroad success of French mining companies (Africa, North America, South America, Australia, Asia); 5 - exploration and exploitation; 6 - uranium economy: perspectives of uranium demand, present day production status, secondary resources, possible resources, market balances, prices and trends, future availability and nuclear perspectives. (J.S.)

Uranium 2014: Resources, Production and Demand

International Nuclear Information System (INIS)

2014-01-01

Uranium is the raw material used to fuel over 400 operational nuclear reactors around the world that produce large amounts of electricity and benefit from life cycle carbon emissions as low as renewable energy sources. Although a valuable commodity, declining market prices for uranium since the Fukushima Daiichi nuclear power plant accident in 2011, driven by uncertainties concerning the future of nuclear power, have led to the postponement of mine development plans in a number of countries and raised questions about continued uranium supply. This 25. edition of the 'Red Book', a recognised world reference on uranium jointly prepared by the OECD Nuclear Energy Agency and the International Atomic Energy Agency, provides analyses and information from 45 producing and consuming countries in order to address these and other questions. It includes data on global uranium exploration, resources, production and reactor-related requirements. It offers updated information on established uranium production centres and mine development plans, as well as projections of nuclear generating capacity and reactor-related requirements through 2035, incorporating policy changes following the Fukushima accident, in order to address long-term uranium supply and demand issues. (authors)

Arsenic speciation and uranium concentrations in drinking water supply wells in Northern Greece: Correlations with redox indicative parameters and implications for groundwater treatment

International Nuclear Information System (INIS)

Katsoyiannis, Ioannis A.; Hug, Stephan J.; Ammann, Adrian; Zikoudi, Antonia; Hatziliontos, Christodoulos

2007-01-01

The cities in the Aksios and Kalikratia areas in Northern Greece rely on arsenic contaminated groundwater for their municipal water supply. As remedial action strongly depends on arsenic speciation, the presence of other possible contaminants, and on the general water composition, a detailed study with samples from 21 representative locations was undertaken. Arsenic concentrations were typically 10-70 μg/L. In the groundwaters of the Aksios area with lower Eh values (87-172 mV), pH 7.5-8.2 and 4-6 mM HCO 3 alkalinity, As(III) predominated. Manganese concentrations were mostly above the EC standard of 0.05 mg/L (0.1-0.7 mg/L). In groundwaters of the Kalikratia area with higher Eh values (272-352 mV), pH 6.7-7.5 and 6-12 mM HCO 3 alkalinity, As(V) was the main species. Uranium in the groundwaters was also investigated and correlations with total arsenic concentrations and speciation were examined to understand more of the redox chemistry of the examined groundwaters. Uranium concentrations were in the range 0.01-10 μg/L, with the higher concentrations to occur in the oxidizing groundwaters of the Kalikratia area. Uranium and total arsenic concentrations showed no correlation, whereas uranium concentrations correlated strongly with As(III)/As(tot) ratios, depicting their use as a possible indicator of groundwater redox conditions. Finally, boron was found to exceed the EC drinking water standard of 1 mg/L in some wells in the Kalikratia area and its removal should also be considered in the design of a remedial action

Status of technology of uranium recovery from seawater

International Nuclear Information System (INIS)

Sugo, Takanobu; Saito, Kyoichi.

1990-01-01

By bringing the solid material called adsorbent in contact with seawater, uranium can be collected, therefore, the adsorbent to which uranium was adsorbed in seawater can be regarded as the resource of uranium storing. To the adsorbent, also rare metals are concentrated in addition to uranium. From such viewpoint, the development of the technology for collecting seawater uranium is important for the Japanese energy policy. The uranium concentration in seawater is about 3 mg/m 3 and its form of dissolution is uranyl tricarbonate ions. The technology of collecting seawater uranium is the separation technology for extracting the component of very low concentration from the aqueous solution containing many components. The total amount of uranium in the whole oceans reaches about 4 billion t, which is about 1000 times as much as the uranium commercially mined on land. It is the target of the technology to make artificial uranium ore of as high quality as possible quickly. The process of collecting seawater uranium comprises adsorption, desorption, separation and enrichment. As the adsorbents, hydrated titanium oxide and chelate resin represented by amidoxime are promising. The adsorption system is described. (K.I.)

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

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

International Nuclear Information System (INIS)

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

2004-12-01

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

Lung cancer and inhaled uranium ore dust in rats

International Nuclear Information System (INIS)

Mitchel, R.E.J.; Jackson, J.S.

1997-01-01

Using a nose only inhalation system, 187 nine week old male Sprague-Dawley rats were exposed to two different concentrations of natural uranium ore dust aerosol (44% U) without significant radon content. Inhalation exposures averaged about 4.2 h/day, 5 days/week for 65 weeks at which point lung uranium burdens in the two groups averaged 0.9 and 1.9 mg/g dry weight. Animals (63) exposed to the air stream without dust served as controls. After inhalation exposure ceased, the rats were allowed to live for their natural lifetime, a maximum of about 900 days after the start of dust inhalation. Lung uranium burdens were measured at the time of death of each animal. Lung burdens were found to decline exponentially after dust inhalation ceased, and the rate of decline was independent of the initial lung burden. All lungs were examined at necropsy and histologically for lung tumors. Lung tumors of lung origin were observed in both exposed groups and in the control group. The frequency of primary malignant lung tumors was 0.016, 0.175 and 0.328 and primary non-malignant lung tumors 0.016, 0.135 and 0.131 in the control low and high aerosol exposed groups respectively. Absorbed dose to the lung was calculated for each animal in the study. The average maximum doses for all the animals exposed to the low or high concentration of dust aerosol were 0.87 Gy and 1.64 Gy respectively. The average risk of malignant lung tumors from inhaled natural uranium ore dust was therefore about 0.20 tumors/animal/Gy. For animals with lung tumors, the average doses were 0.98 and 1.90 in the exposed groups. In both exposed groups, the frequency of primary malignant or non-malignant lung tumors was significantly greater than in the control group (p < 0.02) and the frequency of primary malignant lung tumors in the two exposed group were significantly different from each other (p = 0.05). The frequency of primary lung tumors (malignant and non-malignant) was calculated as a function of dose

Worldwide developments in uranium

International Nuclear Information System (INIS)

Hoellen, E.E.

1987-01-01

World uranium production will continue to change in most major producing nations. Canadian production will increase and will be increasingly dominated by western producers as eastern Canadian high-cost production declines. Australian production will increase as major projects come into operation before 2000. US production will stabilize through the end of the century. South African production will be dependent upon the worldwide support for economic sanctions. China's entry into the world market injects yet another variable into the already cloudy supply picture. Many risks and uncertainties will face uranium producers through the 1980s. Recognizing that the uranium industry is not a fast-growing market, many existing and potential producers are seeking alternate investment courses, causing a restructuring of the world uranium production industry in ways not anticipated even a few years ago. During the restructuring process, world uranium production will most likely continue to exceed uranium consumption, resulting in a further buildup of world uranium inventories. Inventory sales will continue to redistribute this material. As inventory selling runs its course, users will turn to normal sources of supply, stimulating additional production to meet needs. Stimulation in the form of higher prices will be determined by how fast producers are willing and able to return to the market. Production costs are expected to have an increasing impact as it has become apparent that uranium resources are large in comparison to projected consumption. Conversely, security-of-supply issues have seemed to be of decreasing magnitude as Canada, Australia, and other non-US producers continue to meet delivery commitments

Valence-associated uranium isotope fractionation of uranium enriched phosphate in a shallow aquifer, Lee County, Florida

International Nuclear Information System (INIS)

Weinberg, J.M.; Levine, B.R.; Cowart, J.B.

1993-01-01

The source of anomalously high concentrations of uranium, characterized by U-234/U-238 activity ratios significantly less than unity, in shallow groundwaters of Lee County, Florida, was investigated. Uranium in cores samples was separated into U(IV) and U(VI) oxidation state fractions, and uranium analyses were conducted by alpha spectrometry. Uranium mobility was also studied in selected leaching experiments. Results indicate that mobilization of unusually soluble uranium, present in uranium enriched phosphate of the Pliocene age Tamiami Formation at determined concentrations of up to 729 ppm, is the source for high uranium concentrations in groundwater. In leaching experiments, approximately one-third of the uranium present in the uranium enriched phosphate was mobilized into the aqueous phase. Results of previous investigations suggest that U-234, produced in rock by U-238 decay, is selectively oxidized to U(VI). The uranium enriched phosphate studied in this investigation is characterized by selective reduction of U-234, with a pattern of increasing isotopic fractionation with core depth. As a consequence, U-234/U-238 activity ratios greater than 1.0 in the U(IV) fraction, and less than 1.0 in the U(VI) fraction have developed in the rock phase. In leaching experiments, the U(VI) fraction from the rock was preferentially mobilized into the aqueous phase, suggesting that U-234/U-238 activity ratios of leaching groundwaters are strongly influenced by the isotopic characteristics of the U(VI) fraction of rock. It is suggested that preferential leaching of U(VI), present in selectivity reduced uranium enriched phosphate, is the source for low activity ratio groundwaters in Lee County

Study of the dry processing of uranium ores; Etude des traitements de minerais d'uranium par voie seche

Energy Technology Data Exchange (ETDEWEB)

Guillet, H

1959-02-01

A description is given of direct fluorination of pre-concentrated uranium ores in order to obtain the hexafluoride. After normal sulfuric acid treatment of the ore to eliminate silica, the uranium is precipitated by a load of lime to obtain: either impure calcium uranate of medium grade, or containing around 10% of uranium. This concentrate is dried in an inert atmosphere and then treated with a current of elementary fluorine. The uranium hexafluoride formed is condensed at the outlet of the reaction vessel and may be used either for reduction to tetrafluoride and the subsequent manufacture of uranium metal or as the initial product in a diffusion plant. (author) [French] Il s'agit d'une description de fluoration directe de preconcentres de minerais d'uranium en vue d'obtention d'hexafluorure. Apres attaque sulfurique normale du minerai, afin d' eliminer la silice, l' uranium est precipite par un toit de chaux pour obtenir: ou uranate de chaux impur de titre moyen, ou uranium de la dizaine du pourcentage. Ce concentre seche en atmosphere inerte est soumis a un courant de fluor elementaire. L'hexafluorure d'uranium forme est condense a la sortie du reacteur et peut etre utilise soit apres reduction en tetrafluorure par l'elaboration d'uranium metal, soit comme produit de base dans le cadre d'une usine de diffusion. (auteur)

Uranium removal from water by five aquatic plants

International Nuclear Information System (INIS)

Hu Nan; Ding Dexin; Li Guangyue; Wang Yongdong; Li Le; Zheng Jifang

2012-01-01

Hydroponic solution culture experiments were conducted on the growth of Eichhornia crassipes, Lemna minor L, Azolla imbircata, Potamogeton crispus, and Alligator alternanthera Herb in water with 0.15, 1.50 and 15.00 mg . L -1 concentrations of uranium, and on the uranium removal from the water by the aquatic plants. For the 21 days of hydroponic solution culture experiments, Azolla imbircata exhibited the strongest resistance to uranium and its growth inhibition rates induced by the water with 0.15, 1.50 and 15.00 mg · L -1 concentrations of uranium were 4.56%, 2.48%, 6.79%, respectively, and the uranium removal rates from the water by the plant amounted to 94%, 97% and 92%, respectively. Further experiments revealed that the most uranium removal could be achieved when 7.5 g Azolla imbircata was grown in 1 L of water, and the time required for the plant to reduce the uranium concentration in water with 1.25, 2.50, 5.00 and 10.00 mg · L -l concentrations of uranium below that stipulated in the national emission standards of China were 17, 19, 23 and 25 days, respectively. The results have laid foundation for further studies of phytoremediation of uranium contaminated water. (authors)

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

Discussion on prospecting potential for rich uranium deposits in Xiazhuang uranium ore-field, northern Guangdong

International Nuclear Information System (INIS)

Wu Lieqin; Tan Zhengzhong

2004-01-01

Based on analyzing the prospecting potential for uranium deposits in Xiazhuang uranium ore field this paper discusses the prospecting for rich uranium deposits and prospecting potential in the region. Research achievements indicate: that the Xiazhuang ore-field is an ore-concentrated area where uranium has been highly enriched, and possesses good prospecting potential and perspective, becoming one of the most important prospecting areas for locating rich uranium deposits in northern Guangdong; that the 'intersection type', the alkaline metasomatic fractured rock type and the vein-group type uranium deposits are main targets and the prospecting direction for future uranium prospecting in this region

Data release for intermediate-density hydrogeochemical and stream sediment sampling in the Vallecito Creek Special Study Area, Colorado, including concentrations of uranium and forty-six additional elements

International Nuclear Information System (INIS)

Warren, R.G.

1981-04-01

A sediment sample and two water samples were collected at each location about a kilometer apart from small tributary streams within the area. One of the two water samples collected at each location was filtered in the field and the other was not. Both samples were acidified to a pH of < 1; field data and uranium concentrations are listed first for the filtered sample (sample type = 07) and followed by the unfiltered sample (sample type = 27) for each location in Appendix I-A. Uranium concentrations are higher in unfiltered samples than in filtered samples for most locations. Measured uranium concentrations in control standards analyzed with the water samples are listed in Appendix II. All sediments were air dried and the fraction finer than 100 mesh was separated and analyzed for uranium and forty-six additional elements. Field data and analytical results for each sediment sample are listed in Appendix I-B. Analytical procedures for both water and sediment samples are briefly described in Appendix III. Most bedrock units within the sampled area are of Precambrian age. Three Precambrian units are known or potential hosts for uranium deposits; the Trimble granite is associated with the recently discovered Florida Mountain vein deposit, the Uncompahgre formation hosts a vein-type occurrence in Elk Park near the contact with the Irving formation, and the Vallecito conglomerate has received some attention as a possible host for a quartz pebble conglomerate deposit. Nearly all sediment samples collected downslope from exposures of Timble granite (geologic unit symbol ''T'' in Appendix I) contain unusually high uranium concentrations. High uranium concentrations in sediment also occur for an individual sample location that has a geologic setting similar to the Elk Park occurrence and for a sample associated with the Vallecito conglomerate

National uranium project - an initiative to generate national database on uranium in drinking water of the country

International Nuclear Information System (INIS)

Sahoo, S.K.; Tripathi, R.M.; Jha, V.N.; Kumar, Ajay; Patra, A.C.; Vinod Kumar, A.

2018-01-01

Uranium is a naturally occurring lithophilic heavy element found in earth crust since inception of the earth. It is present naturally in all rock and soil and the concentration depends on geological formation and local geology. Groundwater interact with the host rocks and the wet weathering process facilitate the solubility of uranium in groundwater. The concentration of uranium in groundwater is influenced by geo-chemical parameters such as host rock characteristics and pH, Eh, ORP, ligands, etc. of the interacting water medium. Uranium is a radioactive element of low specific activity (25 Bq/mg) having both chemical and radiological toxicity but its chemical toxicity supersede the radio-toxicity. After a reporting of high uranium content in drinking water of Punjab, BARC has taken a pro-active initiative to generate a national database on uranium in drinking water in all the districts of India under National Uranium Project (NUP)

The Influences of Uranium Concentration and Polyvinyl Alcohol on the Quality UO2 Microsphere for Fuel of High Temperature Reactor

International Nuclear Information System (INIS)

Damunir; Sukarsono; Bangun-Wasito; Endang Nawangsih

2000-01-01

The influences of uranium concentration and PVA on the quality of UO 2 microspheres for fuel of high temperature reactor have been investigated. The UO 2 particles were prepared by gel precipitation using internal gelation process. Uranyl nitrate solution containing uranium of 100 g/l was neutralized using NH 4 OH 1 M. The solution was changed into sol by adding 60 g PVA/l solution while stirred and heated up to 80 o C for 20 minutes. In order to find gels in spherical shape, the sol solution was dropped into 5 M NH 4 OH medium. The formed gels were small spheres, was washed, screened and heated up to 120 o C. After that, the gels were calcined at 800 o C for 4 hours, resulting in U 3 O 8 spheres. The U 3 O 8 particles were reduced using H 2 gas in a N 2 media at 800 o C for 4 hours, yielded in UO 2 spheres. Using a similar procedure, the influence of uranium concentration of 150-250 g/l and PVA 40-80 g/l were studied. The qualities of UO 2 particles were obtained by their physical properties, i.e. density, specific surface area, total volume of pores and pore radius using surface area meter and N 2 gas used as absorbent, and the particle size was observed using optical microscope. The result showed that the changing of uranium and PVA concentrations on the internal gelation affected the density, specific surface area, total volume of pores and pore radius of UO 2 particles. (author)

Statistical data of the uranium industry

International Nuclear Information System (INIS)

1976-01-01

Historical facts and figures of the uranium industry through 1975 are compiled. Areas covered are ore and concentrate purchases; uranium resources; distribution of $10, $15, and $30 reserves; drilling statistics; uranium exploration expenditures; land holdings for uranium mining and exploration; employment; commercial U 3 O 8 sales and requirements; and processing mills

Uranium concentrations in the phosphates of Congo related to marin and continental mineral authigenesis

International Nuclear Information System (INIS)

Giresse, P.; N'Landou, J. de Dieu; Wiber, M.

1984-01-01

In the Maastrichtian phosphates of Tchivoula (Congo), uanium, for the most part fixed and tetravalent in marine apatites in there after mobilized and occasionally concentrates during the course of successive stages of dissolution, recrystallization (secondary apatite) or authigenesis (ferro-aluminous phosphates, autunite and torbernite). Very high levels near the top of the deposit appear to be related to the percolation of uraniferous solutions from Ypresian phosphatic beds which are no longer present. In the marine Tertiary phosphates of Djeno, diagenesis is less advanced; radial changes in uranium concentration on the scale of individual coprolites of selacians can be observed and are related to the loss of P 2 O 5 [fr

Assessment of heavy metal concentration in water around the proposed Mkuju river uranium project in Tanzania

International Nuclear Information System (INIS)

Banzi, F.P.; Msaki, P.K.; Mohammed, N.K.

2015-01-01

Effective verification for compliance with water quality standards in uranium mining in Tanzania requires data sensitive to monitor heavy metal concentration in water around the Mkuju River Uranium Project before mining commences. The area susceptible for pollution by the project was estimated using AERMOD dispersion model and found to cover about 1300 km"2. Thirty one surface and groundwater samples were collected and analysed for heavy metals and physicochemical properties using ICP-MS and standards techniques, respectively. The physicochemical properties for water samples analysed ranges from 5.7 to 7.8 for pH, 2.8 to 80.2 mg/L for TDS and 15 to 534.5 mS/cm for EC. These values show that the water in the vicinity of the Mkuju River Uranium Project is normal. The ranges of concentration of heavy metals (µgL"-"1) determined in water ranges were: Al(2 to 9049), Cr(0.2 to 19.96), Mn (0.1 to 1452), Fe(2 to 53890), Co(0.02 to 27.63), Ni(0.2 to 9.7), Cu(2 to 17), Zn(2 to 62.94), As(0.4 to 19.17), Cd(0.02 to 0.14), Pb (0.02 to 78.68), Th (0.002 to 1.73), U(0.002 to 29.76). These values are below the tolerance levels of concentrations set by different International organisations. Therefore heavy metal toxicity in the study area is marginal. The parameters that could serve as baseline data because of their enhanced sensitivity to pollution were (i) concentration of chromium, cobalt, nickel, copper, zinc, arsenic, cadmium and lead in water (ii) pH, TDS and EC for water, (iii) TDS ratio for surface to ground water values and (iv) correlation coefficients between the heavy metals. However, since TDS values are season dependent, this indicator can serve as baseline data when measured during the dry season as was the case in the study. (author)

Simultaneous analysis of uranium and nitrate

Energy Technology Data Exchange (ETDEWEB)

Bostick, D.T.

1978-04-01

A direct spectrophotometric method has been developed for the determination of 20 to 200 g/l of uranium in the presence of 3 to 5 M nitric acid. A dual-wavelength analysis is used to eliminate the enhancing effect of nitrate ion on the uranium visible spectra. The precision and accuracy of the simultaneous analysis of uranium and nitrate were compared using combinations of the four uranium wavelength maxima, occurring at 426, 416, 403 and 359 nm. Calculations based on 426 and 416 nm data yielded the most accurate results. The calculated relative standard deviation of uranium and nitrate concentrations was 5.4 percent and 15.5 percent, respectively. The photometric procedure is slightly affected by temperature; an increase of one degree centigrade results in a 0.2 g/l overestimation of uranium concentration. Because the method is non-destructive, it is directly applicable to the continuous in-line analysis of dissolved uranium in aqueous fuel reprocessing streams.

Uranium concentrations in natural waters, South Park, Colorado. [Part of National Uranium Resource Evaluation program

Energy Technology Data Exchange (ETDEWEB)

Sharp, R.R. Jr.; Aamodt, P.L.

1976-08-01

During the summer of 1975, 464 water samples from 149 locations in South Park, Colorado, were taken for the Los Alamos Scientific Laboratory in order to test the field sampling and analytical methodologies proposed for the NURE Hydrogeochemical and Stream Sediment Reconnaissance for uranium in the Rocky Mountain states and Alaska. The study showed, in the South Park area, that the analytical results do not vary significantly between samples which were untreated, filtered and acidified, filtered only, or acidified only. Furthermore, the analytical methods of fluorometry and delayed-neutron counting, as developed at the LASL for the reconnaissance work, provide fast, adequately precise, and complementary procedures for analyzing a broad range of uranium in natural waters. The data generated using this methodology does appear to identify uraniferous areas, and when applied using sound geochemical, geological, and hydrological principles, should prove a valuable tool in reconnaissance surveying to delineate new districts or areas of interest for uranium exploration.

Concentration of gold, sulphide minerals, and uranium oxide minerals by flotation from ores and metallurgical plant products

International Nuclear Information System (INIS)

Weston, D.

1976-01-01

A process is described for the concentration by flotation of gold, gold bearing minerals and uranium oxide minerals from ores and metallurgical plant products. A pulp of a ground ore is agitation conditioned in at least two agitation conditioning stages wherein in at least one stage the pH of the pulp is lowered with an acid agent to within the pH range of about 1.5 to 5.0, and wherein in at least one additional agitation conditioning stage the pH of the pulp is raised to within the pH range of about 6.0 to 11.0 and wherein in at least the last stage prior to flotation at least one collector selected from the group of sulfhydryl anionic collectors is present. Subsequently, the at least two stage agitation conditioned pulp is subjected to flotation to produce a flotation concentrate enriched in at least one of the mineral values from the group consisting of gold, gold bearing minerals and uranium minerals

Introduction. Physicochemical aspects of uranium concentrates obtaining from the wastes and raw materials

International Nuclear Information System (INIS)

Mirsaidov, I.U.

2014-01-01

The uranium deposits of Tajikistan played an immensely significant role in the practical solution of a radioactive raw materials problem which appeared during the post-World War II years in the USSR. The pioneer in this field became complex №6 (currently known as 'Vostokredmet'). The first soviet uranium was produced from the ores extracted from the republic's deposits. For 50 years (1945-1995 y.), uranium bearing raw materials from all over the former USSR were delivered to Tajikistan, and uranium oxide was produced, which was later delivered back to Russia for further production of enriched uranium. The total volume of uranium produced in Tajikistan plants was approximately 100 thousands tons. In Sughd region, during that period, more than 55 million tons of uranium waste was accumulated. The total activity of the waste, according to different calculations, is approximately 240-285 TBq. The total amount of waste in dumps and tailings piles is estimated to be more than 170 million tons, most of which are located in the neighborhoods of hydrometallurgical plants and heap leaching locations. Uranium industry wastes in Northern Tajikistan have become attractive for different investors and commercial companies, from secondary reprocessing of mines and tailings' point of view, since the uranium price is increasing. In this regard, research on developing uranium extraction methods from wastes is broadening. The study of the possibility and economic reasonability of reprocessing former year's dumps requires comprehensive examination, and relates not only to uranium extraction but to safe extraction of dumps from tailings as well.

Interaction of uranium with Pleurotus sp

International Nuclear Information System (INIS)

Ohnuki, Toshihiko; Sakamoto, Fuminori; Kozaki, Naofumi; Ozaki, Takuro; Samadfam, Mohammad

2002-01-01

Uptake of uranium by higher fungi, such as mushroom is little elucidated. We have studied the interaction of uranium with Pleurotus sp. (a mushroom) in pure culture over a wide range of U concentration (50-3000 mg/L). The Pleurotus sp. was cultured in two different media. One was rice bran medium, and the other was agar (yeast extract, peptone and dextrose) medium. The uptake of uranium in Pleurotus sp. was examined by alpha ray autoradiography (A,A), X-ray fluorescence spectroscopy (XRF) and scanning microcopy (SEM) equipped with EDS. In the agar medium, the higher uranium concentration gave lower growth of mycelia, and no fruiting body was observed. In the rice bran medium, the fruiting body was grown at U concentrations up to 1000 mg/L. The AA and XRF analysis showed that uranium taken up in the fruiting body was below the detection limit. The SEM-EDS analysis indicated that U was distributed in the limited region and was not transported to the mycelia far from U containing medium. It is concluded that uranium affects the growth of Pleurotus sp., and little uranium is taken up by Pleurotus sp. during the growth of both mycelia and fruiting body. (author)

Testing of a uranium downhole logging system to measure in-situ plutonium concentrations in sediments

International Nuclear Information System (INIS)

Kasper, R.B.; Kay, M.A.; Bruns, L.E.; Stokes, J.A.; Steinman, D.K.; Adams, J.

1980-11-01

A prototype urainium borehole logging system, developed for uranium exploration, was modified for Pu assay and testing at the site. It uses the delayed fission neutron (DFN) method. It was tested in a retired Pu facility, the 216-Z-1A Crib. General agreement between laboratory determined Pu concentrations in sediment samples and neutron flux measurements was found for the relative distribution with depth

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

Detailed uranium hydrogeochemical and stream sediment reconnaissance data release for the eastern portion of the Montrose NTMS Quadrangle, Colorado, including concentrations of forty-five additional elements

International Nuclear Information System (INIS)

Maassen, L.W.

1981-01-01

In September and October 1979, the Los Alamos Scientific Laboratory (LASL) conducted a detailed geochemical survey for uranium primarily in the Sawatch Range in the eastern part of the Montrose National Topographic Map Series (NTMS) quadrangle, Colorado, as part of the National Hydrogeochemical and Stream Sediment Reconnaissance (HSSR). Totals of 1034 water and 2087 sediment samples were collected from streams and springs from 2088 locations within a 5420-km 2 area. Statistical data for uranium concentrations in water and sediment samples are presented. Elemental concentration, field measurement, weather, geologic, and geographic data for each sample location are listed for waters and for sediments in appendices. Uranium/thorium ratios for sediment samples are also included. This report contains uranium analyses for water samples and multielement analyses for sediment samples. Sediments were analyzed for uranium and thorium as well as Al, Sb, As, Ba, Be, Bi, Cd, Ca, Ce, Cs, Cl, Cr, Co, Cu, Dy, Eu, Au, Hf, Fe, La, Pb, Li, Lu, Mg, Mn, Ni, Nb, K, Rb, Sm, Sc, Se, Ag, Na, Sr, Ta, Tb, Sn, Ti, W, V, Yb, Zn, and Zr. All elemental analyses were performed at the LASL. Water samples were analyzed for uranium by fluorometry. Sediments were analyzed for uranium by delayed neutron counting. Other elemental concentrations in sediments were determined by neutron activation analysis for 31 elements, by x-ray fluorescence for 12 elements, and by arc-source emission spectrography for 2 elements. Descriptions of procedures as analytical precisions and detection limits are given in the appendix

Adsorption behaviour of uranium on immobilized tannin resin

International Nuclear Information System (INIS)

Olivares, Susana; Preval, Ivon; Santana, Jorge L.; Martinez, Francisco; Vargas, Luis M.

1995-01-01

The sorption of uranium by Eucalyptus Saligna Sm. tannin resin was investigated. This resin resulted a suitable adsorbent for the concentration of uranium from aqueous systems. The sorption of uranium is pH dependent. The presence of appreciable quantities of sodium chloride does not have any effect on uranium removal. Carbonate and calcium ions in concentrations similar to these found in seawater and other natural water do not decrease the uranium uptake. TANNsorb resin can be used several times without an appreciable decay of their sorption capacity. (author). 8 refs., 4 figs., 1 tab

Formation mechanism of uranium minerals at sandstone-type uranium deposits

International Nuclear Information System (INIS)

Li Shengfu; Zhang Yun

2004-01-01

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

Uranium purchasing and stockpiling policies of European utilities

International Nuclear Information System (INIS)

Messer, K.P.

1984-01-01

Most European utilities almost entirely depend on uranium imports. Around 1970 there was a worldwide oversupply of uranium, and utilities concluded short and medium term supply contracts for initial power plant programs. A few years later the situation had changed, with uranium becoming scarce and expensive. Many European utilities decided to participate, directly or indirectly, in the exploration and development of uranium resources. In 1984 most utilities believed that long term contracts from each of the big producer regions should supply 20-25% of their demand. Some remaining demand was reserved for the spot market and reprocessed fuel. This buying policy has t be supplemented by uranium stockpiles corresponding to the demand for the coming two years. However, with the declining worldwide economy power demand has not grown as predicted, and supply contracts have obliged utilities to take delivery of more uranium than needed. Stockpiles have grown larger than planned. (L.L.) (7 figs.)

REE characteristics and uranium metallogenesis of sandstone-type uranium deposits in northern Sichuan

International Nuclear Information System (INIS)

Zhu Xiyang; Wang Yunliang; Wang Zhichang; Zhang Chengjiang

2004-01-01

On the basis of the analysis of a large number of samples at sandstone-type uranium deposits in northern Sichuan, this paper analyses the REE composition of country rocks, ores, calcite-veins and uranium minerals, and systematically summarizes their REE geochemical characteristics, and discusses variation regularity of REE during depositional and diagenetic processes. By comparing these characteristics with those of typical hydrothermal volcanics-type and metamorphic rock type uranium deposits both at home and abroad, authors suggest that sandstone-type uranium deposits in northern Sichuan are characterized by REE geochemical features of hydrothermal reworking metallogenesis, the uranium mineralization has experienced two stages: the diagenetic preconcentration and the concentration of hydrothermal reworking

Concentration of Uranium Radioisotopes in Albanian Drinking Waters Measured by Alpha Spectrometry

Science.gov (United States)

Bylyku, Elida; Cfarku, Florinda; Deda, Antoneta; Bode, Kozeta; Fishka, Kujtim

2010-01-01

Uranium is a radioactive material that is frequently found in rocks and soil. When uranium decays, it changes into different elements that are also radioactive, including radon, a gas that is known to cause a lung cancer. The main concern with uranium in drinking water is harm to the kidneys. Public water systems are required to keep uranium levels at or below 500 mBq per liter to protect against kidney damage. Such an interest is needed due to safety, regulatory compliance and disposal issue for uranium in the environment since uranium is included as an obligatory controlled radionuclide in the European Legislation (Directive 98/83 CE of Council of 03.11.1998). The aim of this work is to measure the levels of uranium in drinking and drilled well waters in Albania. At first each sample was measured for total Alpha and total Beta activity. The samples with the highest levels of total alpha activity were chosen for the determination of uranium radioisotopes by alpha spectrometry. A radiochemical procedure using extraction with TBP (Tri-Butyl-Phosphate) is used in the presence of U232 as a yield tracer. Thin sources for alpha spectrometry are prepared by electrodepositing on to stainless steel discs. The results of the U238 activity measured in the different samples, depending from their geological origin range between 0.55-13.87 mBq/l. All samples measured results under the European Directive limits for U238 (5-500 mBq/1), Dose Coefficients according to Directive 96/29 EURATOM.

Microbial uptake of uranium, cesium, and radium

Energy Technology Data Exchange (ETDEWEB)

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

1980-01-01

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

Solubility measurement of uranium in uranium-contaminated soils

International Nuclear Information System (INIS)

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

1993-08-01

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

Accumulation of uranium by filamentous green algae under natural environmental conditions

International Nuclear Information System (INIS)

Aleissa, K.A.; Shabana, El-Said K.; Al-Masoud, F.L.S.

2004-01-01

The capacity of algae to concentrate uranium under natural environmental conditions is measured by a-spectrometry. Spirogyra, a filamentous green fresh-water alga, has concentrated uranium from a surface concrete ponds with elevated uranium levels (140-1140 ppb). The concentration factors (CFs) ranged from 8.9-67 with an average value of 22. Cladophora spp, a filamentous green marine alga has concentrated uranium from the marine water with a concentration factor ranged from 220-280. The average concentration factor was 250. The factors affecting the sorption process are discussed in detail. (author)

The US uranium mining industry: 1980 and today

International Nuclear Information System (INIS)

Stover, D.E.

1991-01-01

In 1980, 16 800 tonnes of uranium were produced in the United States, making it the largest producing nation with about 40% of Western World (WOCA) production. By 1990, US production had fallen to approximately 3500 tonnes U, representing only about 10% of WOCA production. Clearly the US uranium mining industry was strongly altered by the events of the intervening years. Widespread focus on declining prices overshadowed a second important set of events. Namely, the rapidly changing regulatory and environmental atmosphere in the United States which continues adversely to affect conventional uranium mining. As a result of these events, the size and structure of the US uranium mining industry was irrevocably changed. Within this altered industry is a rapidly maturing technology that provides a more efficient and lower-cost means of uranium production, in-situ leaching (ISL). By exploiting the advantages of relatively low capital investments, shorter development times, reduced labour costs, and increased production flexibility of ISL mining, the US uranium mining industry will be a competitive component of the world's uranium supply for the 1990s. (author)

Uranium in surficial deposits and waters at Palmottu

International Nuclear Information System (INIS)

Ahonen, L.; Blomqvist, R.; Ervanne, H.; Suksi, J.; Jaakkola, T.

1994-01-01

Occurrence of uranium in surficial formations in the vicinity of an underground U deposit was studied. Several water samples from the Lake Palmottu and nearby springs, three lake sediment cores and three peat cores were collected for the study. Uranium concentrations in the water samples varied from 1.4 to 6.9 mBq/l, reflecting the average concentration of near-surface waters in Finland. In some samples, however, the 234 U/ 238 U activity ratio and water chemistry suggest a partial mixing with deeper groundwaters. In the lake sediments, uranium concentrations increases from 53 Bq/kg in surface layer to five fold in the bottom layers deposited 9000 years ago. In peat cores large variations in uranium concentrations can be observed: from tens of Bq/kg to over 20 kBq/kg of peat ash. The large variation also in the 234 U/ 238 U activity ratio, from 0.79 to l.91, tends to indicate uranium migration to the peat from more than one uranium source. (orig.) (19 refs., 5 figs., 1 tab.)

Study of the dry processing of uranium ores; Etude des traitements de minerais d'uranium par voie seche

Energy Technology Data Exchange (ETDEWEB)

Guillet, H

1959-02-01

A description is given of direct fluorination of pre-concentrated uranium ores in order to obtain the hexafluoride. After normal sulfuric acid treatment of the ore to eliminate silica, the uranium is precipitated by a load of lime to obtain: either impure calcium uranate of medium grade, or containing around 10% of uranium. This concentrate is dried in an inert atmosphere and then treated with a current of elementary fluorine. The uranium hexafluoride formed is condensed at the outlet of the reaction vessel and may be used either for reduction to tetrafluoride and the subsequent manufacture of uranium metal or as the initial product in a diffusion plant. (author) [French] Il s'agit d'une description de fluoration directe de preconcentres de minerais d'uranium en vue d'obtention d'hexafluorure. Apres attaque sulfurique normale du minerai, afin d' eliminer la silice, l' uranium est precipite par un toit de chaux pour obtenir: ou uranate de chaux impur de titre moyen, ou uranium de la dizaine du pourcentage. Ce concentre seche en atmosphere inerte est soumis a un courant de fluor elementaire. L'hexafluorure d'uranium forme est condense a la sortie du reacteur et peut etre utilise soit apres reduction en tetrafluorure par l'elaboration d'uranium metal, soit comme produit de base dans le cadre d'une usine de diffusion. (auteur)

Recovery of uranium in mine waters; Recuperation de l'uranium dans les eaux des mines

Energy Technology Data Exchange (ETDEWEB)

Sugier, P [Direction des Productions, CEA, Chatillon-Sur-Bagneux (France)

1967-06-15

In a brief introductory survey the author indicates the date on which leaching was first observed in the CEA mines and lists the main factors necessary for, or favourable to, the solubilization of uranium in mines. Information is given on the various sources of this type at present identified in France and the methods used to recover uranium in mines situated near ore-concentration plants. An explanation is given for the use of the calcium precipitation technique in connection with waters produced in mines not situated near ore-concentration plants. Data are given on the results of laboratory tests carried out on waters containing uranium, together with a description of an industrial-scale facility built in consequence of these tests. Details are given of the statistical results obtained. The author concludes by outlining the programme which will be implemented in the near future with a view to increasing the tonnage of uranium produced by in situ leaching and indicates that the CEA engineers are very optimistic about the prospects of this new low-cost method of producing uranium. (author) [French] Apres un bref rappel historique precisant la date de constatation du phenomene de lixiviation dans les mines d'uranium du Commissariat et un rapide inventaire des principales conditions necessaires ou favorisant la solubilisation de l'uranium dans les mines, auteur indique les differentes sources actuellement reconnues en France et les methodes utilisees pour recuperer l'uranium dans les mines situees pres d'une usine de concentration des minerais. Il donne ensuite les raisons motivant le choix du procede de precipitation calcique pour les eaux produites dans des mines eloignees des usines de concentration des minerais. Les resultats d'essais de laboratoire effectues sur des eaux chargees en uranium sont donnes et l'installation industrielle realisee a la suite de ces essais est decrite; les resultats statistiques obtenus sont detailles. En conclusion de son expose, l

Chapter 3. Classical method of uranium leaching from ores and reasons for incomplete recovery at dumps of State Enterprise 'VOSTOKREDMET'. 3.3. Basic regularities of uranium ores leaching

International Nuclear Information System (INIS)

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

2012-01-01

Present article is devoted to basic regularities of uranium ores leaching. It was found that the basic method of uranium ores enrichment and producing of reasonably rich and pure uranium concentrates (usually technical uranium oxide) is a chemical concentration concluded in selective uranium leaching from ore raw materials with further, uranium compounds - so called uranium chemical concentrates. Such reprocessing of uranium ores with the purpose of uranium chemical concentrates production, currently, are produced everywhere by hydrometallurgical methods. This method in comparison with enrichment and thermal reprocessing is a universal one. Hydrometallurgy - the part of chemical technology covering so called moist methods of metals and their compounds (in the current case, uranium) extraction from raw materials, where they are contained. It can be ores or ore concentrates produced by radiometric, gravitational, floatation enrichment, sometimes passed through high-temperature reprocessing or even industry wastes. The basic operation in hydrometallurgy is its important industrial element - metal or metals leaching as one or another compound. Leaching is conversion of one or several components to solution under impact of relevant technical solvents: water, water solutions, acids, alkali or base, solution of some salts and etc. The basic purpose of leaching in uranium technology is to obtain the most full and selective solution of uranium.

Determination of the concentration of radionuclides in soil and water next the uranium mine of Caetite, Bahia, Brazil

International Nuclear Information System (INIS)

Almeida, Geangela M.; Souza, Susana O.; Campos, Simara S.S.; Gennari, Roseli F.

2011-01-01

The economic growing in Brazil is responsible for an urgent demand for energy. Uranium is the fuel used to generate nuclear power. Brazil has the sixth largest reserve of the uranium ore in the world and, nowadays there is only one mine under exploration (Uraniferous District of Lagoa Real - Caetite-BA). Some Non-Governmental Organizations (NGOs), such as Greenpeace, state that the explored uranium mine is dangerous and polluting, causing water contamination by uranium. So, the population would be receiving radiation doses above permissible limits. However, Industrias Nucleares do Brasil (INB) the company in charge of the complex extraction and production of yellow cake rejected these accusations. The main purpose of this work is the determination of the composition of natural radionuclides in the Uraniferous District of Lagoa Real in order to determine if the nearest population is exposed to environmental radiation. It was checked if there is water contamination due to the natural transport in the uranium mining surroundings. Soil and water samples from Caetite mine and also from nearby town were collected. Only one water sample collected had concentrations higher than the limits recommended by World Health Organization. The presence of radionuclides in soil samples is considered independent of mineral exploration. The effective dose rates in almost all samples are above the world average which is 2.4 mSv/y. To sum up, the presence of uranium in water and soil of the tested areas is probably due to the nature of the soil and not to the exploration of mine. (author)

Determination of the concentration of radionuclides in soil and water next the uranium mine of Caetite, Bahia, Brazil

Energy Technology Data Exchange (ETDEWEB)

Almeida, Geangela M.; Souza, Susana O. [Federal University of Sergipe (UFS), Sao Cristovao, SE (Brazil). Dept. of Physics; Campos, Simara S.S. [State University of Southwest Bahia (UESB), Itapetinga, BA (Brazil). Dept. of Basic and Instrumental Studies; Gennari, Roseli F., E-mail: rgennari@dfn.if.usp.b [University of Sao Paulo (USP), Sao Paulo, SP (Brazil). Inst. of Physics. Dept. of Nuclear Physics

2011-07-01

The economic growing in Brazil is responsible for an urgent demand for energy. Uranium is the fuel used to generate nuclear power. Brazil has the sixth largest reserve of the uranium ore in the world and, nowadays there is only one mine under exploration (Uraniferous District of Lagoa Real - Caetite-BA). Some Non-Governmental Organizations (NGOs), such as Greenpeace, state that the explored uranium mine is dangerous and polluting, causing water contamination by uranium. So, the population would be receiving radiation doses above permissible limits. However, Industrias Nucleares do Brasil (INB) the company in charge of the complex extraction and production of yellow cake rejected these accusations. The main purpose of this work is the determination of the composition of natural radionuclides in the Uraniferous District of Lagoa Real in order to determine if the nearest population is exposed to environmental radiation. It was checked if there is water contamination due to the natural transport in the uranium mining surroundings. Soil and water samples from Caetite mine and also from nearby town were collected. Only one water sample collected had concentrations higher than the limits recommended by World Health Organization. The presence of radionuclides in soil samples is considered independent of mineral exploration. The effective dose rates in almost all samples are above the world average which is 2.4 mSv/y. To sum up, the presence of uranium in water and soil of the tested areas is probably due to the nature of the soil and not to the exploration of mine. (author)

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

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)

Bacterial leaching of waste uranium materials.

Science.gov (United States)

Barbic, F F; Bracilović, D M; Krajincanić, B V; Lucić, J L

1976-01-01

The effect of ferrobacteria and thiobacteria on the leaching of waste uranium materials from which 70-80% of uranium was previously leached by classical chemical hydrometallurgical procedure has been investigated. The bacteria used are found in the ore and the mine water of Zletovska River locality, Yugoslavia. Parameters of biological leaching were examined in the laboratory. Leaching conditions were changed with the aim of increasing the amount of uranium leached. The effect of pyrite added to the waste materials before the beginning of leaching has also been examined. Uranium leaching is directly proportional to the composition and number of ferrobacteria and thiobacteria, and increased by almost twice the value obtained from the same starting materials without using bacteria. Increased sulphuric acid concentrations stimulate considerably the rate of leaching. Uranium leaching is increased up to 20% while sulphuric acid consumption is simultaneously decreased by the addition of pyrite. Uranium concentrations in starting waste materials used for leaching were extremely low (0.0278 and 0.372% U) but about 60% recovery of uranium was obtained, with relatively low consumption of sulphuric acid.

Bacterial leaching of waste uranium materials

International Nuclear Information System (INIS)

Barbic, F.F.; Bracilovic, D.M.; Krajincanic, B.V.; Lucic, J.L.

1976-01-01

The effect of ferrobacteria and thiobacteria on the leaching of waste uranium materials from which 70-80% of uranium was previously leached by classical chemical hydrometallurgical procedure has been investigated. The bacteria used are found in the ore and the mine water of Zletovska River locality, Yugoslavia. Parameters of biological leaching were examined in the laboratory. Leaching conditions were changed with the aim of increasing the amount of uranium leached. The effect of pyrite added to the waste materials before the beginning of leaching has also been examined. Uranium leaching is directly proportional to the composition and number of ferrobacteria and thiobacteria, and increased by almost twice the value obtained from the same starting materials without using bacteria. Increased sulphuric acid concentrations stimulate considerably the rate of leaching. Uranium leaching is increased up to 20% while sulphuric acid consumption is simultaneously decreased by the addition of pyrite. Uranium concentrations in starting waste materials used for leaching were extremely low (0.0278 and 0.0372% U) but about 60% recovery of uranium was obtained, with relatively low consumption of sulphuric acid. (author)

Concentration and characteristics of depleted uranium in biological and water samples collected in Bosnia and Herzegovina

International Nuclear Information System (INIS)

Jia Guogang; Belli, Maria; Sansone, Umberto; Rosamilia, Silvia; Gaudino, Stefania

2006-01-01

During Balkan conflicts in 1994-1995, depleted uranium (DU) ordnance was employed and was left in the battlefield. Health concern is related to the risk arising from contamination of the environment with DU penetrators and dust. In order to evaluate the impact of DU on the environment and population in Bosnia and Herzegovina, radiological survey of DU in biological and water samples were carried out over the period 12-24 October 2002. The uranium isotopic concentrations in biological samples collected in Bosnia and Herzegovina, mainly lichens, mosses and barks, were found to be in the range of 0.27-35.7 Bq kg -1 for 238 U, 0.24-16.8 Bq kg -1 for 234 U, and 0.02-1.11 Bq kg -1 for 235 U, showing uranium levels to be higher than in the samples collected at the control site. Moreover, the 236 U in some of the samples was detectable. The isotopic ratios of 234 U/ 238 U showed DU to be detectable in many biological samples at most sites examined, but in very low levels. The presence of DU in the biological samples was as a result of DU contamination in air. The uranium concentrations in water samples collected in Bosnia and Herzegovina were found to be in the range of 0.27-16.2 mBq l -1 for 238 U, 0.41-15.6 mBq l -1 for 234 U and 0.012-0.695 mBq l -1 for 235 U, and two water samples were observed to be DU positive; these values are much lower than those in mineral water found in central Italy and below the WHO guideline for public drinking water. From radiotoxicological point of view, at this moment there is no significant radiological risk related to these investigated sites in terms of possible DU contamination of water and/or plants

Washing technology development for gravel contaminated with uranium

Energy Technology Data Exchange (ETDEWEB)

Park, Uk Ryang; Kim, Gye Nam; Kim, Seung Soo; Kim, Wan Suk; Moon, Jai Kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2013-10-15

The soil washing method has a short decontamination time and is economical. In addition, methods including phytoremediation, solidification/stabilization and bioremediation exist. Phytoremediation and bioremediation are economical, but have low remedial efficiency. In addition, bioremediation causes washing wastewater because it requires a washing process for the separation of microorganisms from the soils. In addition, solidification/stabilization is a commonly used methods, but eventually increases the volume of wastes. As mentioned above, many researches involved in the decontamination of radioactively contaminated soils have been actively processed. On the other hand, researches for decontaminating radioactively contaminated gravels are not being currently processed. In this study, we performed basic experiments using decontamination methods to decontaminate radioactively contaminated gravel. First, we measured the concentration of uranium in gravel included in uranium-contaminated soils and performed a washing experiment to monitor the tendency of uranium removal. In addition, when managing gravel with a low uranium-decontamination rate, we tried to satisfy the radioactivity concentration criteria for self-disposal in the wastes (0.4Bq/g or less) by performing a washing experiment after only a physical crushing process. We performed washing experiments to satisfy the radioactivity concentration criteria for self-disposal (0.4 Bq/g or less) in gravel included in radioactively contaminated soil. We performed washing experiments for gravel whose initial average concentration of uranium was 1.3Bq/g. In addition, the average concentration of uranium was 0.8Bq/g. Too increase the decontamination rate, we crushed the gravel with a jaw crusher and performed the washing experiments. The results were similar to the results without crushing. In addition, it was determined that the smaller the size of the gravel particles, the more efficient the uranium decontamination

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

Uranium extraction from phosphoric acid

International Nuclear Information System (INIS)

Araujo Figueiredo, C. de

1984-01-01

The recovery of uranium from phosphoric liquor by two extraction process is studied. First, uranium is reduced to tetravalent condition and is extracted by dioctypyrophosphoric acid. The re-extraction is made by concentrated phosphoric acid with an oxidizing agent. The re-extract is submitted to the second process and uranium is extracted by di-ethylhexilphosphoric acid and trioctylphosphine oxide. (M.A.C.) [pt

US uranium market developments

International Nuclear Information System (INIS)

Krusiewski, S.V.; Thomas, D.C.

1981-01-01

Domestic uranium delivery commitments for the 1981 to 1990 period reached a peak in the July 1980 survey and then declined in the January 1981 survey and again in the July 1981 survey. However, there are sizable sales contracts through the mid-1980s. In the latter part of this decade, unfilled requirements increase which can provide a needed market for domestic producers. Older contracts are helping to keep the average contract prices, including market price settlements, rather stable. However, average market price settlements decreased from data reported in January 1981, but some of these deliveries represent settlement of litigation. Foreign uranium procurement is scheduled to exceed deliveries of US uranium to foreign buyers in the 1981 to 1990 period. However, the actual use of foreign uranium has been quite low as US enrichment services customers have preferred to buy US uranium. Based on over four and one-half years of data, only about 7% foreign uranium has been brought to the Department of Energy for enrichment. Inventories of natural and enriched uranium in buyers' hands continue to increase. This is a concern to the uranium-producing industry. However, the industry should not be concerned about DOE-owned inventories, which are needed to supply Government requirements. There is absolutely no plan to dispose of DOE inventories on the commercial market. Capital expenditures reached a peak of $800 million in 1979. This decreased to $780 million in 1980, although higher expenditures were planned for the year. A very sharp reduction in plans for 1981, from $830 to $450 million, has been reported. A further reduction to $350 million is planned for 1982. However, it is interesting to note that the planned expenditures for 1982 are above the expenditures for 1975, a period of industury expansion

Biosorption of uranium and lead by Streptomyces longwoodensis

International Nuclear Information System (INIS)

Friis, N.; Myers-Keith, P.

1986-01-01

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

Uranium content measurement in drinking water samples using track etch technique

International Nuclear Information System (INIS)

Kumar, Mukesh; Kumar, Ajay; Singh, Surinder; Mahajan, R.K.; Walia, T.P.S.

2003-01-01

The concentration of uranium has been assessed in drinking water samples collected from different locations in Bathinda district, Punjab, India. The water samples are taken from hand pumps and tube wells. Uranium is determined using fission track technique. Uranium concentration in the water samples varies from 1.65±0.06 to 74.98±0.38 μg/l. These values are compared with safe limit values recommended for drinking water. Most of the water samples are found to have uranium concentration above the safe limit. Analysis of some heavy metals (Zn, Cd, Pb and Cu) in water is also done in order to see if some correlation exists between the concentration of uranium and these heavy metals. A weak positive correlation has been observed between the concentration of uranium and heavy metals of Pb, Cd and Cu

Ultraviolet-B radiation mobilizes uranium from uranium-dissolved organic carbon complexes in aquatic systems, demonstrated by asymmetrical flow field-flow fractionation.

Science.gov (United States)

Nehete, Sachin Vilas; Christensen, Terje; Salbu, Brit; Teien, Hans-Christian

2017-05-05

Humic substances have a tendency to form complexes with metal ions in aquatic medium, impacting the metal mobility, decreasing bioavailability and toxicity. Ultraviolet-B (UV-B) radiation exposure degrades the humic substance, changes their molecular weight distribution and their metal binding capacity in aquatic medium. In this study, we experimented the effect of UV-B radiation on the uranium complexed with fulvic acids and humic acids in a soft water system at different pH, uranium concentrations and radiant exposure. The concentration and distribution of uranium in a complexed form were investigated by asymmetrical flow field-flow fractionation coupled to multi detection technique (AsFlFFF-UV-ICP-MS). The major concentration of uranium present in complexes was primarily associated with average and higher molecular weight fulvic and humic acids components. The concentration of uranium in a complexed form increased with increasing fulvic and humic acid concentrations as well as pH of the solution. The higher molecular weight fraction of uranium was degraded due to the UV-B exposure, transforming about 50% of the uranium-dissolved organic carbon complexes into low molecular weight uranium species in complex form with organic ligands and/or free form. The result also suggests AsFlFFF-UV-ICP-MS to be an important separation and detection technique for understanding the interaction of radionuclides with dissolved organic matter, tracking size distribution changes during degradation of organic complexes for understanding mobility, bioavailability and ecosystem transfer of radionuclides as well as metals. Copyright © 2017 Elsevier B.V. All rights reserved.

Uranium concentrations in stream waters and sediments from selected sites in the eastern Seward Peninsula, Koyukuk, and Charley River areas, and across South-Central Alaska

International Nuclear Information System (INIS)

Sharp, R.R. Jr.; Hill, D.E.

1978-04-01

During the summer of 1975, a 6-week reconnaissance was conducted in widespread areas of Alaska as part of the National Uranium Resource Evaluation (NURE) program; Water, stream sediment, and bedrock samples were taken from the eastern Seward Peninsula, from north of Koyukuk River, from the Charley River area, and from across south central Alaska. This report contains the LASL uranium determinations resulting from fluorometric analysis of the water samples and delayed-neutron counting of the stream sediment samples. Results of total uranium for 611 water and 641 sediment samples, from 691 stream locations, are presented. Overlays showing the numbered sample locations and graphically portraying the concentrations of uranium in water and stream sediment samples, at 1:250,000 scale for use with existing National Topographic Map Series (NTMS) sheets and published geologic maps, are provided as plates. The main purposes of this work are to make the uranium data available to the public in the standard computer format used in the NURE Hydrogeochemical and Stream Sediment Reconnaissance (i.e., with a DOE sample number giving the latitude and longitude of each sample location) and to provide uranium concentration overlays at the standard scale of 1:250,000 adopted by the DOE for the NURE program. It also allows a plausible explanation of differences between the uranium values for sediment as determined by acid dissolution/extraction/fluorometry and by delayed-neutron counting that were noted in the earlier report

Optimization of uranium leach mining

International Nuclear Information System (INIS)

Schecter, R.S.; Bommer, P.M.

1982-01-01

The effects of well pattern and well spacing on uranium recovery and oxidant utilization are considered. As expected, formation permeability heterogeneities and anisotropies are found to be important issues requiring careful consideration; however, it also is shown that the oxidant efficiency and the produced uranium solution concentrations are sensitive to the presence of other minerals competing with uranium for oxidant. If the Damkohler number for competing minerals, which measures the speed of the reaction, exceeds that for uranium, the competing mineral will have to be oxidized completely to recover a large proportion of the uranium. If the Damkohler number is smaller, it may be possible to achieve considerable selectivity for uranium by adjusting the well spacing. 9 refs