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Sample records for natural uranium irradiated

  1. Capital and operating costs of irradiated natural uranium reprocessing plants

    International Nuclear Information System (INIS)

    Thiriet, L.; Jouannaud, C.; Couture, J.; Duboz, J.

    1966-01-01

    This paper presents first a method of analysing natural uranium reprocessing plants investment costs (method similar to LANG and BACH well known in the fuel oil industry) and their operating costs (analysed according to their economic type). This method helps establishing standard cost structures for these plants, allowing thus comparisons between existing or planned industrial facilities. It also helps evaluating the foreseeable consequences of technical progress. Some results obtained are given, concerning: the investment costs sensitivity to the various technical parameters defining the fuel and their comparison according to the country or the economic area taken into account. Finally, the influence of the plants size on their investment costs is shown. (author) [fr

  2. Irradiated uranium reprocessing

    International Nuclear Information System (INIS)

    Gal, I.

    1961-12-01

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

  3. Long term developments in irradiated natural uranium processing costs. Optimal size and siting of plants

    International Nuclear Information System (INIS)

    Thiriet, L.

    1964-01-01

    The aim of this paper is to help solve the problem of the selection of optimal sizes and sites for spent nuclear fuel processing plants associated with power capacity programmes already installed. Firstly, the structure of capital and running costs of irradiated natural uranium processing plants is studied, as well as the influence of plant sizes on these costs and structures. Shipping costs from the production site to the plant must also be added to processing costs. An attempt to reach a minimum cost for the production of a country or a group of countries must therefore take into account both the size and the location of the plants. The foreseeable shipping costs and their structure (freight, insurance, container cost and depreciation), for spent natural uranium are indicated. Secondly, for various annual spent fuel reprocessing programmes, the optimal sizes and locations of the plants are determined. The sensitivity of the results to the basic assumptions relative to processing costs, shipping costs, the starting up year of the plant programme and the length of period considered, is also tested. - this rather complex problem, of a combinative nature, is solved through dynamic programming methods. - It is shown that these methods can also be applied to the problem of selecting the optimal sizes and locations of processing plants for MTR type fuel elements, related to research reactor programmes, as well as to future plutonium element processing plants related to breeder reactors. Thirdly, the case where yearly extraction of the plutonium contained in the irradiated natural uranium is not compulsory is examined; some stockpiling of the fuel is then allowed some years, entailing delayed processing. The load factor of such plants is thus greatly improved with respect to that of plants where the annual plutonium demand is strictly satisfied. By including spent natural uranium stockpiling costs an optimal rhythm of introduction and optimal sizes for spent fuel

  4. Comparison Between Calculated and Measured Cross Section Changes in Natural Uranium Irradiated in NRX

    Energy Technology Data Exchange (ETDEWEB)

    Ahlstroem, P E

    1961-03-15

    It is desirable to obtain an experimental check of the reliability of the methods currently used to determine reactivity changes in a reactor and, with a view to meeting this requirement to some extent, a preliminary comparison has been made between calculated and measured cross-section changes in rods of natural uranium irradiated in NRX. The measurements were made at Harwell in the GLEEP reactor and a description has been given by, inter alia, Ward and Craig. The theory of the calculations, which is briefly described in this report, has been indicated by Littler. The investigation showed that the methods for calculating burn up used at present provides a good illustration of the long-term variations in isotope contents. A satisfactory agreement is obtained with experimental results when calculating apparent cross-section changes in uranium rods due to irradiation if the fission cross- section for {sup 239}Pu is set to 780 b. This is 34 b higher than the figure quoted in BNL - 325 (1958). However, in order to get a good idea as to whether the calculated long-term variations in reactivity really correspond to reality, it is necessary to make further investigations. For this reason the results quoted in this report should be regarded as preliminary.

  5. Natural uranium

    International Nuclear Information System (INIS)

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

    2014-08-01

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

  6. Capital and operating costs of irradiated natural uranium reprocessing plants; Couts d'investissement et d'exploitation des usines de retraitement de l'uranium naturel irradie

    Energy Technology Data Exchange (ETDEWEB)

    Thiriet, L; Jouannaud, C; Couture, J; Duboz, J [Commissariat a l' Energie Atomique (France). Centre d' Etudes Nucleaires; Oger, C [Saint Gobain Nucleaire (France)

    1966-07-01

    This paper presents first a method of analysing natural uranium reprocessing plants investment costs (method similar to LANG and BACH well known in the fuel oil industry) and their operating costs (analysed according to their economic type). This method helps establishing standard cost structures for these plants, allowing thus comparisons between existing or planned industrial facilities. It also helps evaluating the foreseeable consequences of technical progress. Some results obtained are given, concerning: the investment costs sensitivity to the various technical parameters defining the fuel and their comparison according to the country or the economic area taken into account. Finally, the influence of the plants size on their investment costs is shown. (author) [French] La communication expose d'abord une methode d'analyse des couts d'investissement des usines de retraitement de l'uranium naturel irradie (inspiree de celles de LANG et de BACH, bien connues dans l'industrie petroliere) et de leurs couts d'exploitation (selon leur nature economique). Cette methode permet d'etablir des structures types de couts de ces usines et de comparer les realisations industrielles et les projets. Elle facilite l'exploration des consequences previsibles du progres technique. On indique un certain nombre de resultats obtenus, concernant la sensibilite des couts d'investissement de ces usines aux differents parametres techniques definissant le combustible et leur confrontation selon les pays ou aires economiques envisages. On montre enfin comment doit pouvoir s'exprimer l'influence de la taille des usines sur leur cout d'investissement. (auteur)

  7. Long term developments in irradiated natural uranium processing costs. Optimal size and siting of plants; Perspectives a long terme des couts de traitement de l'uranium naturel irradie. Tailles et localisations optimales des usines

    Energy Technology Data Exchange (ETDEWEB)

    Thiriet, L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Oger, C; Vaumas, P de [Saint-Gobain Nucleaire, 92 - Courbevoie (France)

    1964-07-01

    The aim of this paper is to help solve the problem of the selection of optimal sizes and sites for spent nuclear fuel processing plants associated with power capacity programmes already installed. Firstly, the structure of capital and running costs of irradiated natural uranium processing plants is studied, as well as the influence of plant sizes on these costs and structures. Shipping costs from the production site to the plant must also be added to processing costs. An attempt to reach a minimum cost for the production of a country or a group of countries must therefore take into account both the size and the location of the plants. The foreseeable shipping costs and their structure (freight, insurance, container cost and depreciation), for spent natural uranium are indicated. Secondly, for various annual spent fuel reprocessing programmes, the optimal sizes and locations of the plants are determined. The sensitivity of the results to the basic assumptions relative to processing costs, shipping costs, the starting up year of the plant programme and the length of period considered, is also tested. - this rather complex problem, of a combinative nature, is solved through dynamic programming methods. - It is shown that these methods can also be applied to the problem of selecting the optimal sizes and locations of processing plants for MTR type fuel elements, related to research reactor programmes, as well as to future plutonium element processing plants related to breeder reactors. Thirdly, the case where yearly extraction of the plutonium contained in the irradiated natural uranium is not compulsory is examined; some stockpiling of the fuel is then allowed some years, entailing delayed processing. The load factor of such plants is thus greatly improved with respect to that of plants where the annual plutonium demand is strictly satisfied. By including spent natural uranium stockpiling costs an optimal rhythm of introduction and optimal sizes for spent fuel

  8. Strong demand for natural uranium

    International Nuclear Information System (INIS)

    Kalinowski, P.

    1975-01-01

    The Deutsches Atomforum and the task group 'fuel elements' of the Kerntechnische Gesellschaft had organized an international two-day symposium in Mainz on natural uranium supply which was attended by 250 experts from 20 countries. The four main themes were: Demand for natural uranium, uranium deposits and uranium production, attitude of the uranium producing countries, and energy policy of the industrial nations. (orig./AK) [de

  9. Interpretation of measurements made by oscillations of irradiated fuels in natural uranium, graphite-gas piles

    International Nuclear Information System (INIS)

    Laponche, Bernard; Luffin, Jean; Brunet, Max; Guerange, Jacques; Tonolli, Jacky

    1969-06-01

    When considering a pile operation, it is interesting to know the evolution of fuel quality with respect to irradiation, i.e. the variation of its fission rate and of its absorption rate. In order to experimentally obtain these features, a method is to introduce an irradiated cartridge into a critical reactor and to measure the induced effect on its reactivity and on the neutron density at the vicinity of the cartridge. An oscillation method presented in another document and based on a periodic introduction of fuel sample into a critical reactor allows, from the measurement of reactivity variation (global signal), and of the neutron density (local signal), effective macroscopic fission and absorption cross sections of this sample to be obtained. As previous studies revealed that the interpretation of the local signal was notably delicate, this information has been replaced by computed information, the fission rate, which is determined by means of the COREGRAF1 code. Thus, the remaining quantity to be obtained is the fuel absorption rate. The authors report studies performed on several sets of cartridges from different reactors, and with an irradiation range from about 700 to 4000 MWJ/T. In a first part, they describe the characteristics of the studied cartridges, their irradiation and measurement conditions, and the use of the evolution code. In a second part, they try to define the interpretation of oscillation-based measurements by using two methods, a first and fast one which gives an approximation of results, and a more elaborated second one which complies with measurement conditions. The last part presents and discusses the obtained results [fr

  10. Behaviour of uranium under irradiation

    International Nuclear Information System (INIS)

    Adda, Y.; Mustelier, J.P.; Quere, Y.; Commissariat a l'Energie Atomique, Fontenay-aux-Roses

    1964-01-01

    The main results obtained in a study of the formation of defects caused in uranium by fission at low temperature are reported. By irradiation at 20 K. it was possible to determine the number of Frenkel pairs produced by one fission. An analysis of the curves giving the variations in electrical resistivity shows the size of the displacement spikes and the mechanism of defect creation due to fission. Irradiations at 77 K gave additional information, showing behaviour differences in the case of recrystallised and of cold worked uranium. The diffusion of rare gases was studied using metal-rare gas alloys obtained by electrical discharge, and samples of irradiated uranium. Simple diffusion is only responsible for the release of the rare gases under vacuum in cases where the rare gas content is very low (very slightly irradiated U). On the other hand when the concentration is higher (samples prepared by electrical discharge) the gas is given off by the formation, growth and coalescence of bubbles; the apparent diffusion coefficient is then quite different from the true coefficient and cannot be used in calculations on swelling. The various factors governing the phenomenon of simple diffusion were examined. It was shown in particular that a small addition of molybdenum could reduce the diffusion coefficient by a factor of 100. The precipitation of gas in uranium (Kr), in silver (Kr) and in Al-Li alloy (He) have been followed by measurement of the crystal parameter and of the electrical resistivity, and by electron microscope examination of thin films. The important part played by dislocations in the generation and growth of bubbles has been demonstrated, and it has been shown also that precipitation of bubbles on the dislocation lattice could block the development of recrystallisation. The results of these studies were compared with observations made on the swelling of uranium and uranium alloys U Mo and U Nb strongly irradiated between 400 and 700 C. In the case of Cubic

  11. Uranium briquettes for irradiation target

    Energy Technology Data Exchange (ETDEWEB)

    Saliba-Silva, Adonis Marcelo; Garcia, Rafael Henrique Lazzari; Martins, Ilson Carlos; Carvalho, Elita Fontenele Urano de; Durazzo, Michelangelo, E-mail: saliba@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Direct irradiation on targets inside nuclear research or multiple purpose reactors is a common route to produce {sup 99}Mo-{sup 99m}Tc radioisotopes. Nevertheless, since the imposed limits to use LEU uranium to prevent nuclear armament production, the amount of uranium loaded in target meats has physically increased and new processes have been proposed for production. Routes using metallic uranium thin film and UAl{sub x} dispersion have been used for this purpose. Both routes have their own issues, either by bringing difficulties to disassemble the aluminum case inside hot cells or by generating great amount of alkaline radioactive liquid rejects. A potential route might be the dispersion of powders of LEU metallic uranium and nickel, which are pressed as a blend inside a die and followed by pulse electroplating of nickel. The electroplating provides more strength to the briquettes and creates a barrier for gas evolution during neutronic disintegration of {sup 235}U. A target briquette platted with nickel encapsulated in an aluminum case to be irradiated may be an alternative possibility to replace other proposed targets. This work uses pulse Ni-electroplating over iron powder briquette to simulate the covering of uranium by nickel. The following parameters were applied 10 times for each sample: 900Hz, -0.84A/square centimeters with duty cycle of 0.1 in Watts Bath. It also presented the optical microscopy analysis of plated microstructure section. (author)

  12. Uranium briquettes for irradiation target

    International Nuclear Information System (INIS)

    Saliba-Silva, Adonis Marcelo; Garcia, Rafael Henrique Lazzari; Martins, Ilson Carlos; Carvalho, Elita Fontenele Urano de; Durazzo, Michelangelo

    2011-01-01

    Direct irradiation on targets inside nuclear research or multiple purpose reactors is a common route to produce 99 Mo- 99m Tc radioisotopes. Nevertheless, since the imposed limits to use LEU uranium to prevent nuclear armament production, the amount of uranium loaded in target meats has physically increased and new processes have been proposed for production. Routes using metallic uranium thin film and UAl x dispersion have been used for this purpose. Both routes have their own issues, either by bringing difficulties to disassemble the aluminum case inside hot cells or by generating great amount of alkaline radioactive liquid rejects. A potential route might be the dispersion of powders of LEU metallic uranium and nickel, which are pressed as a blend inside a die and followed by pulse electroplating of nickel. The electroplating provides more strength to the briquettes and creates a barrier for gas evolution during neutronic disintegration of 235 U. A target briquette platted with nickel encapsulated in an aluminum case to be irradiated may be an alternative possibility to replace other proposed targets. This work uses pulse Ni-electroplating over iron powder briquette to simulate the covering of uranium by nickel. The following parameters were applied 10 times for each sample: 900Hz, -0.84A/square centimeters with duty cycle of 0.1 in Watts Bath. It also presented the optical microscopy analysis of plated microstructure section. (author)

  13. Irradiated uranium reprocessing; Prerada ozracenog urana

    Energy Technology Data Exchange (ETDEWEB)

    Gal, I [Institute of Nuclear Sciences Boris Kidric, Laboratorijaza visoku aktivnost, Vinca, Beograd (Serbia and Montenegro)

    1961-12-15

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

  14. 31 CFR 540.317 - Uranium feed; natural uranium feed.

    Science.gov (United States)

    2010-07-01

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

  15. 31 CFR 540.309 - Natural uranium.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Natural uranium. 540.309 Section 540... FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.309 Natural uranium. The term natural uranium means uranium found in...

  16. The market for natural uranium

    International Nuclear Information System (INIS)

    Bauder, P.

    1981-01-01

    The natural uranium market is characterized at present by its surplus. This is essentially due to a surplus on the production line. The uranium produced is no longer taken up by the market as it was up to the middle of 1979. The object of this contribution is therefore a survey on the present availability and demand situation, as well as to discuss market mechanisms and forecast the future market trend. (orig./IHO) [de

  17. Study of the recrystallisation of irradiated uranium

    International Nuclear Information System (INIS)

    Bloch, J.; Mustelier, J.P.; Bussy, P.; Blin, J.

    1958-01-01

    1- Study of the recrystallisation of irradiated uranium. The recrystallisation of uranium irradiated to a burnup level of 220 MWj/t, at a temperature of the order of 350 deg. C, has been investigated. The observations were made chiefly by means of micrography an hardness measurements. If the irradiated metal is compared with a cold-drawn metal showing the same shearing of the twinned crystals, and therefore the same rate of plastic deformation, as the irradiated metal, it is noted that the restoring of the irradiated metal takes place at a considerably higher temperature than that of the cold-drawn metal. Pre-crystallisation is very much delayed. Only, a passage of the α-β transformation point quickly wipes out irradiation effect. 2- Hardening of uranium by irradiation. Using hardness measurements we have studied more especially the effect of very weak irradiations on uranium (integrated flux 16 nvt). The hardness does not increase linearly with the flux, but a period of incubation is observed probably representing the time necessary for saturation of the dislocations. (author) [fr

  18. Determination of irradiated reactor uranium in soil samples in Belarus using 236U as irradiated uranium tracer.

    Science.gov (United States)

    Mironov, Vladislav P; Matusevich, Janna L; Kudrjashov, Vladimir P; Boulyga, Sergei F; Becker, J Sabine

    2002-12-01

    This work presents experimental results on the distribution of irradiated reactor uranium from fallout after the accident at Chernobyl Nuclear Power Plant (NPP) in comparison to natural uranium distribution in different soil types. Oxidation processes and vertical migration of irradiated uranium in soils typical of the 30 km relocation area around Chernobyl NPP were studied using 236U as the tracer for irradiated reactor uranium and inductively coupled plasma mass spectrometry as the analytical method for uranium isotope ratio measurements. Measurements of natural uranium yielded significant variations of its concentration in upper soil layers from 2 x 10(-7) g g(-1) to 3.4 x 10(-6) g g(-1). Concentrations of irradiated uranium in the upper 0-10 cm soil layers at the investigated sampling sites varied from 5 x 10(-12) g g(-1) to 2 x 10(-6) g g(-1) depending on the distance from Chernobyl NPP. In the majority of investigated soil profiles 78% to 97% of irradiated "Chernobyl" uranium is still contained in the upper 0-10 cm soil layers. The physical and chemical characteristics of the soil do not have any significant influence on processes of fuel particle destruction. Results obtained using carbonate leaching of 236U confirmed that more than 60% of irradiated "Chernobyl" uranium is still in a tetravalent form, ie. it is included in the fuel matrix (non-oxidized fuel UO2). The average value of the destruction rate of fuel particles determined for the Western radioactive trace (k = 0.030 +/- 0.005 yr(-1)) and for the Northern radioactive trace (k = 0.035 + 0.009 yr(-1)) coincide within experimental errors. Use of leaching of fission products in comparison to leaching of uranium for study of the destruction rate of fuel particles yielded poor coincidence due to the fact that use of fission products does not take into account differences in the chemical properties of fission products and fuel matrix (uranium).

  19. Study of the recrystallisation of irradiated uranium; Etude sur l'uranium irradie

    Energy Technology Data Exchange (ETDEWEB)

    Bloch, J; Mustelier, J P; Bussy, P; Blin, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    1- Study of the recrystallisation of irradiated uranium. The recrystallisation of uranium irradiated to a burnup level of 220 MWj/t, at a temperature of the order of 350 deg. C, has been investigated. The observations were made chiefly by means of micrography an hardness measurements. If the irradiated metal is compared with a cold-drawn metal showing the same shearing of the twinned crystals, and therefore the same rate of plastic deformation, as the irradiated metal, it is noted that the restoring of the irradiated metal takes place at a considerably higher temperature than that of the cold-drawn metal. Pre-crystallisation is very much delayed. Only, a passage of the {alpha}-{beta} transformation point quickly wipes out irradiation effect. 2- Hardening of uranium by irradiation. Using hardness measurements we have studied more especially the effect of very weak irradiations on uranium (integrated flux < 10{sup 16} nvt). The hardness does not increase linearly with the flux, but a period of incubation is observed probably representing the time necessary for saturation of the dislocations. (author)Fren. [French] 1- Etude de la recristallisation de l'uranium irradie. On a etudie la recristallisation d'uranium irradie jusqu'a un taux de combustion de 220 MWj/t a une temperature de l'ordre de 350 deg. C. Les observations ont ete faites principalement a l'aide de la micrographie et de la durete. Si l'on compare le metal irradie avec un metal ecroui presentant le meme cisaillement des macles, donc le meme taux de deformation plastique que le metal irradie, on constate que la restauration du metal irradie se fait a une temperature notablement superieure a celle du metal ecroui. La recristallisation est tres retardee. Seul, un passage du point de transformation {alpha}-{beta} efface rapidement l'effet de l'irradiation. 2- Durcissement de l'uranium par irradiation. Nous avons, a l'aide de la durete, etudie plus particulierement l'effet de tres faibles irrtions sur l'uranium

  20. Micrographic examination of irradiated uranium

    International Nuclear Information System (INIS)

    Bloch, J.; Bourgues, J.

    1959-01-01

    An installation for the metallographic examination of the EL2 reactor uranium rods has been put into service since September 1955 at the High Activity Lab of CEA Saclay center. This paper describes the apparatuses used for these examinations and presents the results of the micrographic studies of the first three rod assemblies removed from EL2 so far. Reprint of a paper published in Revue de Metallurgie, LV, No. 4, 1958, p. 339-344 [fr

  1. Problems of natural uranium supply

    Energy Technology Data Exchange (ETDEWEB)

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

    1977-11-01

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

  2. Behaviour of uranium under irradiation; Comportement de l'uranium sous irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Adda, Y; Mustelier, J P; Quere, Y [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-07-01

    The main results obtained in a study of the formation of defects caused in uranium by fission at low temperature are reported. By irradiation at 20 K. it was possible to determine the number of Frenkel pairs produced by one fission. An analysis of the curves giving the variations in electrical resistivity shows the size of the displacement spikes and the mechanism of defect creation due to fission. Irradiations at 77 K gave additional information, showing behaviour differences in the case of recrystallised and of cold worked uranium. The diffusion of rare gases was studied using metal-rare gas alloys obtained by electrical discharge, and samples of irradiated uranium. Simple diffusion is only responsible for the release of the rare gases under vacuum in cases where the rare gas content is very low (very slightly irradiated U). On the other hand when the concentration is higher (samples prepared by electrical discharge) the gas is given off by the formation, growth and coalescence of bubbles; the apparent diffusion coefficient is then quite different from the true coefficient and cannot be used in calculations on swelling. The various factors governing the phenomenon of simple diffusion were examined. It was shown in particular that a small addition of molybdenum could reduce the diffusion coefficient by a factor of 100. The precipitation of gas in uranium (Kr), in silver (Kr) and in Al-Li alloy (He) have been followed by measurement of the crystal parameter and of the electrical resistivity, and by electron microscope examination of thin films. The important part played by dislocations in the generation and growth of bubbles has been demonstrated, and it has been shown also that precipitation of bubbles on the dislocation lattice could block the development of recrystallisation. The results of these studies were compared with observations made on the swelling of uranium and uranium alloys U Mo and U Nb strongly irradiated between 400 and 700 C. In the case of Cubic

  3. Enhancement of uranium-accumulating ability of microorganisms by irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Sakaguchi, Takashi; Nakajima, Akira; Tsuruta, Takehiko [Miyazaki Medical Coll., Kiyotake (Japan)

    1998-01-01

    Some microorganisms having excellent ability to accumulate uranium were isolated, from soil and water systems in and around the Ningyo-toge Station of Power Reactor and Nuclear Fuel Development Corporation. The enhancement of uranium-accumulating ability of microorganisms by electron-beam irradiation was examined, and the ability of JW-046 was increased 3-5% by the irradiation. The irradiation affect the growth of some of microorganisms tested. (author)

  4. Ecological considerations of natural and depleted uranium

    International Nuclear Information System (INIS)

    Hanson, W.C.

    1980-01-01

    Depleted 238 U is a major by-product of the nuclear fuel cycle for which increasing use is being made in counterweights, radiation shielding, and ordnance applications. This paper (1) summarizes the pertinent literature on natural and depleted uranium in the environment, (2) integrates results of a series of ecological studies conducted at Los Alamos Scientific Laboratory (LASL) in New Mexico where 70,000 kg of depleted and natural uranium has been expended to the environment over the past 34 years, and (3) synthesizes the information into an assessment of the ecological consequences of natural and depleted uranium released to the environment by various means. Results of studies of soil, plant, and animal communities exposed to this radiation and chemical environment over a third of a century provide a means of evaluating the behavior and effects of uranium in many contexts

  5. Fluorometric analysis for uranium in natural waters

    International Nuclear Information System (INIS)

    Waterbury, G.R.

    1977-01-01

    A fluorometric method is used for the routine determination of uranium at 0.2 to parts-per-billion (ppB) concentrations in natural surface waters. Duplicate 200-μl aliquots of the water samples are pipetted onto 0.4-g pellets of 98 percent NaF-2 percent LiF flux contained in platinum dishes. The pellets are dried under heat lamps and fused over special propane burners. The fused pellets are subjected to ultraviolet radiation and the fluorescence is measured in a fluorometer. The lower limit of detection is 0.2 ppB of uranium, and the precision is about 15 relative percent in the 0.2 to 10 ppB uranium concentration range. Two analysts determine uranium in 750 to 900 samples per week using this method. Samples containing solids or more than 19 ppB of uranium are analyzed by a delayed neutron counting method

  6. The light water natural uranium reactor

    International Nuclear Information System (INIS)

    Radkowsky, A.

    A new type of light water seed blanket with the seed having 20% enrichment and the blanket a special combination of elements of natural uranium and thorium, relatively close packed, but sufficient spacing for heat transfer purpose is described. The blanket would deliver approximately half the total energy for about 10,000 MWDIT, so this type of core would be just as economical or better in uranium ore consumation as present cores. (author)

  7. Irradiation Stability of Uranium Alloys at High Exposures

    International Nuclear Information System (INIS)

    McDonell, W.R.

    2001-01-01

    Postirradiation examinations were begun of a series of unrestrained dilute uranium alloy specimens irradiated to exposures up to 13,000 MWD/T in NaK-containing stainless steel capsules. This test, part of a program of development of uranium metal fuels for desalination and power reactors sponsored by the Division of Reactor Development and Technology, has the objective of defining the temperature and exposure limits of swelling resistance of the alloyed uranium. This paper discusses those test results

  8. Sorption of natural uranium by algerian bentonite

    International Nuclear Information System (INIS)

    Megouda, N.; Kadi, H.; Hamla, M.S.; Brahimi, H.

    2004-01-01

    Full text.Batch sorption experiments have been used to assess the sorption behaviour of uranium onto natural and drilling bentonites. The operating parameters (pH, aolis-liquid ratio, particle size, time and initial uranium concentration) influenced the rate of adsorption. The distribution coefficient (Kd) range values at equilibrium time are 45.95-1079.26 ml/g and 32.81-463053 ml/g for the drilling and natural bentonites respectively. The equilibrium isotherms show that the data correlate with both Freundlich and Langmuir models

  9. Separation of rubidium from irradiated aluminum-encapsulated uranium

    International Nuclear Information System (INIS)

    Horwitz, E.P.; Schmitz, F.J.; Rokop, D.J.

    1982-01-01

    A procedure was developed for separating rubidium from irradiated aluminum encapsulated uranium. The separations procedure produces a final ultra-high purity RbCl product for subsequent high performance mass spectrometric analysis. The procedure involves first removing most of the macro-components and fission products by strong base anion exchange using, first, concentrated HCl, then oxalic acid media and second, selectively separating rubidium from alkaline-earth ions and other alkali-metal ions, including cesium, using Bio-Rex-40 cation-exchange resin. The resultant RbCl is then put through a final vacuum sublimation step. Ultra-pure reagents and specially clean glassware are used throughout the procedure to minimize contamination by naturally-occurring rubidium

  10. Effects of heat and pressure on the swelling of irradiated uranium. Part I

    Energy Technology Data Exchange (ETDEWEB)

    Churcman, A. T.; Barnes, R. S.; Cottrell, A. H.

    1956-09-15

    Small pieces of a natural uranium fuel bar from the NRX reactor which had been irradiated to 0.3 - 0.4% burn up have been heat treated either in vacuo or at high pressure and changes in their density measured.

  11. Irradiation behavior of miniature experimental uranium silicide fuel plates

    International Nuclear Information System (INIS)

    Hofman, G.L.; Neimark, L.A.; Mattas, R.F.

    1983-01-01

    Uranium silicides, because of their relatively high uranium density, were selected as candidate dispersion fuels for the higher fuel densities required in the Reduced Enrichment Research and Test Reactor (RERTR) Program. Irradiation experience with this type of fuel, however, was limited to relatively modest fission densities in the bulk from, on the order of 7 x 10 20 cm -3 , far short of the approximately 20 x 10 20 cm -3 goal established for the RERTR program. The purpose of the irradiation experiments on silicide fuels on the ORR, therefore, was to investigate the intrinsic irradiation behavior of uranium silicide as a dispersion fuel. Of particular interest was the interaction between the silicide particles and the aluminum matrix, the swelling behavior of the silicide particles, and the maximum volume fraction of silicide particles that could be contained in the aluminum matrix

  12. Natural fractionation of uranium isotopes

    International Nuclear Information System (INIS)

    Noordmann, Janine

    2015-01-01

    The topic of this thesis was the investigation of U (n( 238 U) / n( 235 U)) isotope variations in nature with a focus on samples (1) that represent the continental crust and its weathering products (i.e. granites, shales and river water) (2) that represent products of hydrothermal alteration on mid-ocean ridges (i.e. altered basalts, carbonate veins and hydrothermal water) and (3) from restricted euxinic basins (i.e. from the water column and respective sediments). The overall goal was to explore the environmental conditions and unravel the mechanisms that fractionate the two most abundant U isotopes, n( 238 U) and n( 235 U), on Earth.

  13. Natural fractionation of uranium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Noordmann, Janine

    2015-01-24

    The topic of this thesis was the investigation of U (n({sup 238}U) / n({sup 235}U)) isotope variations in nature with a focus on samples (1) that represent the continental crust and its weathering products (i.e. granites, shales and river water) (2) that represent products of hydrothermal alteration on mid-ocean ridges (i.e. altered basalts, carbonate veins and hydrothermal water) and (3) from restricted euxinic basins (i.e. from the water column and respective sediments). The overall goal was to explore the environmental conditions and unravel the mechanisms that fractionate the two most abundant U isotopes, n({sup 238}U) and n({sup 235}U), on Earth.

  14. Analysis of fuel cycles with natural uranium; Analiza gorivnih ciklusa sa prirodnim uranom

    Energy Technology Data Exchange (ETDEWEB)

    Stojanovic, A [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Yugoslavia)

    1965-05-15

    A method was developed and a computer code was written for analysis of fuel cycles and it was applied for heavy water and graphite moderated power reactors. Among a variety of possibilities, three methods which enable best utilization of natural uranium and plutonium production were analyzed. Analysis has shown that reprocessing of irradiated uranium and plutonium utilization in the same or similar type of reactor could increase significantly utilization of natural uranium. Increase of burnup is limited exclusively by costs of reprocessing, plutonium extraction and fabrication of new fuel elements.

  15. The French natural uranium industry in 1986

    International Nuclear Information System (INIS)

    Baron, Marcel

    1987-01-01

    France has relatively large uranium deposits. This led to the creation of an internationally significant uranium mining industry. The structure of this industry is explained. In 1985 world supply of uranium was greater than world demand leading to an increase in uranium stocks. However, as demand is expected to increase, the industry is undertaking extensive uranium exploration, mainly abroad. (UK)

  16. Measurement of the high-energy neutron flux on the surface of the natural uranium target assembly QUINTA irradiated by deuterons of 4- and 8-GeV energy

    International Nuclear Information System (INIS)

    Adam, J.; Baldin, A.A.; Chilap, V.

    2014-01-01

    Experiments with a natural uranium target assembly QUINTA exposed to 4- and 8 GeV deuteron beams of the Nuclotron accelerator at the Joint Institute for Nuclear Research (Dubna) are analyzed. The 129 I, 232 Th, 233 U, 235 U, nat U, 237 Np, 238 Pu, 239 Pu and 241 Am radioactive samples were installed on the surface of the QUINTA set-up and irradiated with secondary neutrons. The neutron flux through the RA samples was monitored by Al foils. The reaction rates of 27 Al(n, y 1 ) 24 Na, 27 Al(n, y 2 ) 22 Na and 27 Al(n, y 3 ) 7 Be reactions with the effective threshold energies of 5, 27 and 119 MeV were measured at both 4- and 8-GeV deuteron beam energies. The average neutron fluxes between the effective threshold energies and the effective ends of the neutron spectra (which are 800 or 1000 MeV for energy of 4- or 8-GeV deuterons) were determined. The evidence for the intensity shift of the neutron spectra to higher neutron energies with the increase of the deuteron energy from 4 to 8 GeV was found from the ratios of the average neutron fluxes. The reaction rates and the average neutron fluxes were calculated with MCNPX2.7 and MARS15 codes.

  17. Projections on the future of the natural uranium industry

    International Nuclear Information System (INIS)

    Ishido, Akio

    1995-01-01

    This discussion looks at the future of the uranium industry and considers what type of procurement policy should be adopted. Viewing the future as an extension of the present, it is possible that supplies of natural uranium will begin to run short around 2015. However, natural uranium will have more resources available than petroleum. If rising uranium prices reinvigorate exploration and lead to the discovery of new uranium deposits, future shortages will be unlikely. Nonetheless, with structural changes expected in the world economy, the nature of natural uranium transactions will no doubt change, thereby increasing the present element of uncertainty that much more. At the same time, the oligopolistic situation created by today's major producers will intensify. Based on these projections, the author has reassessed Japan's past procurement policy of government exploration/development support combined with private-sector uranium purchasing and finds this shared risk approach to be the best. (author)

  18. Analysis of fuel cycles with natural uranium, Phase I; Analiza gorivnih ciklusa sa prirodnim uranom, I faza

    Energy Technology Data Exchange (ETDEWEB)

    Stojadinovic, A; Zivkovic, Z; Raisic, N [Institute of Nuclear Sciences Boris Kidric, Laboratorija za fiziku i dinamiku reaktora, Vinca, Beograd (Serbia and Montenegro)

    1964-12-15

    This paper contains analyses of fuel cycles with natural uranium for the following cases: plutonium recycling is not done; recycling of plutonium and irradiated uranium with the condition of equal multiplication factor at the beginning of each cycle; and recycling of plutonium only.

  19. Developments in natural uranium - graphite reactors

    International Nuclear Information System (INIS)

    Bourgeois, J.

    1964-01-01

    The French natural uranium-graphite power-reactor programme has been developing - from EDF 1 to EDF 4 - in the direction of an increase of the unit power of the installations, of the specific and volume powers, and of an improvement in the operational security conditions. The high power of EDF 4 (500 MWe) and the integration of the primary circuit into the reactor vessel, which is itself made of pre-stressed concrete, make it possible to make the most of the annular fuel elements already in use in EDF 1, and to arrive thus at a very satisfactory solution. The use of an internally cooled fuel element (an annular element) has led to a further step forward: it now becomes possible to increase the pressure of the cooling gas without danger of causing creep in the uranium tube. The use of a pre-stressed concrete vessel makes this pressure increase possible, and the integration of the primary circuit avoids the risk of a rapid depressurization which would be in this case a major danger. This report deals with the main problems presented by this new type of nuclear power station, and gives the main lines of research and studies now being carried out in France. - Neutronic and thermal research has made it possible to consider using large size fuel elements (internal diameter = 77 mm, external diameter 95 mm) while still using natural uranium. - The problems connected with the production of these elements and with their in pile behaviour are the subject of a large programme, both out of pile and in power reactors (EDF 2) and test reactors (Pegase). - The increase in the size of the element leads to a large lattice pitch (35 to 40 cm). This makes it possible to consider having one charging aperture per channel or for a small number of channels, whether the charge machine be inside or outside the pressure vessel. In conclusion are given the main characteristics of a project for a 500 MWe power station using such a fuel element. In particular this project is compared to EDF 4

  20. Behaviour of irradiated uranium silicide fuel revisited

    International Nuclear Information System (INIS)

    Finlay, M. Ross; Hofman, Gerard L.; Rest, Jeffrey; Snelgrove, James L.

    2002-01-01

    Irradiated U 3 Si 2 dispersion fuels demonstrate very low levels of swelling, even at extremely high burn-up. This behaviour is attributed to the stability of fission gas bubbles that develop during irradiation. The bubbles remain uniformly distributed throughout the fuel and show no obvious signs of coalescence. Close examination of high burn-up samples during the U 3 Si 2 qualification program revealed a bimodal distribution of fission gas bubbles. Those observations suggested that an underlying microstructure was responsible for the behaviour. An irradiation induced recrystallisation model was developed that relied on the presence of sufficient grain boundary surface to trap and pin fission gas bubbles and prevent coalescence. However, more recent work has revealed that the U 3 Si 2 becomes amorphous almost instantaneously upon irradiation. Consequently, the recrystallisation model does not adequately explain the nucleation and growth of fission gas bubbles in U 3 Si 2 . Whilst it appears to work well within the range of measured data, it cannot be relied on to extrapolate beyond that range since it is not mechanistically valid. A review of the mini-plates irradiated in the Oak Ridge Research Reactor from the U 3 Si 2 qualification program has been performed. This has yielded a new understanding of U 3 Si 2 behaviour under irradiation. (author)

  1. Uranium

    International Nuclear Information System (INIS)

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

    1992-01-01

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

  2. Recovery of uranium from an irradiated solid target after removal of molybdenum-99 produced from the irradiated target

    Science.gov (United States)

    Reilly, Sean Douglas; May, Iain; Copping, Roy; Dale, Gregory Edward

    2017-10-17

    A process for minimizing waste and maximizing utilization of uranium involves recovering uranium from an irradiated solid target after separating the medical isotope product, molybdenum-99, produced from the irradiated target. The process includes irradiating a solid target comprising uranium to produce fission products comprising molybdenum-99, and thereafter dissolving the target and conditioning the solution to prepare an aqueous nitric acid solution containing irradiated uranium. The acidic solution is then contacted with a solid sorbent whereby molybdenum-99 remains adsorbed to the sorbent for subsequent recovery. The uranium passes through the sorbent. The concentrations of acid and uranium are then adjusted to concentrations suitable for crystallization of uranyl nitrate hydrates. After inducing the crystallization, the uranyl nitrate hydrates are separated from a supernatant. The process results in the purification of uranyl nitrate hydrates from fission products and other contaminants. The uranium is therefore available for reuse, storage, or disposal.

  3. Laboratory simulation studies of uranium mobility in natural waters

    International Nuclear Information System (INIS)

    Giblin, A.M.; Swaine, D.J.; Batts, B.D.

    1981-01-01

    The effects of imposed variations of pH and Eh on aqueous uranium mobility at 25 0 C have been studied in three simulations of natural water systems. Constituents tested for their effect on uranium mobility were: (a) hydrous ferric oxide, to represent adsorptive solids which precipitate or dissolve in response to variations in pH and Eh; (b) kaolinite, representing minerals which, although modified by pH and Eh changes, are present as solids over the pH-Eh range of natural waters; and (c) carbonate, to represent a strong uranium-complexing species. Uranium mobility measurements from each simulation were regressed against pH and Eh within a range appropriate to natural waters. Hydrous ferric oxide and kaolinite each affected uranium mobility, but in separate pH-Eh domains. Aqueous carbonate increased mobility of uranium, and adsorption of UO 2 (CO 3 ) 3 4- caused colloidal dispersion of hydrous ferric oxide, possibly explaining the presence of 'hydrothermal hematite' in some uranium deposits. Enhanced uranium mobility observed in the pH-Eh domains of thermodynamically insoluble uranium oxides could be explained if the oxides were present as colloids. Uranium persisting as a mobile species, even after reduction, has implications for the near surface genesis of uranium ores. (author)

  4. Irradiation performance of uranium-molybdenum alloy dispersion fuels

    International Nuclear Information System (INIS)

    Almeida, Cirila Tacconi de

    2005-01-01

    The U-Mo-Al dispersion fuels of Material Test Reactors (MTR) are analyzed in terms of their irradiation performance. The irradiation performance aspects are associated to the neutronic and thermal hydraulics aspects to propose a new core configuration to the IEA-R1 reactor of IPEN-CNEN/SP using U-Mo-Al fuels. Core configurations using U-10Mo-Al fuels with uranium densities variable from 3 to 8 gU/cm 3 were analyzed with the computational programs Citation and MTRCR-IEA R1. Core configurations for fuels with uranium densities variable from 3 to 5 gU/cm 3 showed to be adequate to use in IEA-R1 reactor e should present a stable in reactor performance even at high burn-up. (author)

  5. Market for natural uranium conversion. Commercial aspect

    International Nuclear Information System (INIS)

    Durret, L.F.

    1986-01-01

    The main activity of COMURHEX is the conversion into uranium hexafluoride of uranium concentrates from mines and owned by electricity producers. Capacities of the 5 uranium converters in the Western World are compared. About 50% of COMUREX turnover is exported. Evolution of the market and of stockpile are reviewed [fr

  6. Distinction between natural and depleted uranium using instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Haddad, Kh.

    2008-01-01

    A convenient method to discriminate between natural and depleted uranium samples was developed in this work. Traces of natural and depleted uranium were irradiated separately and the ratios of 95 Zr/ 103 Ru, 239 Np/ 95 Zr, 239 Np/ 103 Ru were measured. The results show that these ratios can be used as indicators of the uranium isotopic composition of the sample. These ratios are independent of the secular equilibrium of the 238 U with its daughters in the sample and indicate the isotopic composition for trace amounts. Date and truffle samples has been analysed also using this method. Results show that the uranium content in this product was less than the detection limit.(author)

  7. Natural uranium utilization without enrichment and reprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Sekimoto, H.; Toshinsky, V.; Ryu, K. [Tokyo Inst. of Tech. (Japan). Research Lab. for Nuclear Reactors

    2001-07-01

    Two types of fast reactor are investigated to utilize the natural uranium without enrichment and reprocessing in an equilibrium state. The first trial is SFPR. Its fuel-shuffling pattern is optimized. An obtained result gives its peak fuel burnup of 22,5%, power peaking factor of 1.5 and peak excess reactivity of 2,15%. The second trial is CANDLE burnup scheme, where distribution shapes of neutron flux and nuclide densities are constant but move in axial direction with a constant velocity. A feasible solution gives the speed of burning region of 4,1 cm/year, k{sub eff} of 1,02 and average spent fuel burnup of 41%. (author)

  8. The dangers of irradiate uranium in nuclear reactors; Les dangers de l'uranium irradie dans les reacteurs nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Jammet, H; Joffre, H [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1955-07-01

    The danger of the uranium cans sur-activated by the use in the nuclear reactors is triple: - Irradiation from afar, during manipulations of the cans. - Contamination of air when decladding. - Contamination of air by fire of uranium in a reactor in function The first two dangers are usual and can be treated thanks to the rules of security in use in the atomic industry. The third has an accidental character and claimed for the use of special and exceptional rules, overflowing the industrial setting, to reach the surrounding populations. (authors) [French] Le danger des cartouches d'uranium suractive par utilisation dans les reacteurs nucleaires est triple: - Irradiation a distance, lors des manipulations des cartouches. - Contamination de l'air au moment de leur degainage. - Contamination de l'air par incendie d'uranium dans un reacteur en fonctionnement. Les deux premiers dangers sont habituels et peuvent etre traites grace aux regles de securite en usage dans l'industrie atomique. Le troisieme revet un caractere accidentel et reclame l'emploi de regles speciales et exceptionnelles, debordant le cadre industriel, pour atteindre celui des populations environnantes. (auteurs)

  9. Irradiation behavior of experimental miniature uranium silicide fuel plates

    International Nuclear Information System (INIS)

    Hofman, Gerard L.; Neimark, L.A.; Mattas, R.F.

    1983-01-01

    Uranium silicides, because of their relatively high uranium density, were selected as candidate dispersion fuels for the higher fuel densities required in the Reduced Enrichment Research and Test Reactor (RERTR) Program. Irradiation experience with this type of fuel, however, was limited to relatively modest fission densities in the bulk form, on the order of 7 x 10 20 cm -3 , far short of he approximately 20 x 10 20 cm -3 goal established for the RERTR Program. The purpose of the irradiation experiments on silicide fuels in the ORR, therefore, was to investigate the intrinsic irradiation behavior of uranium silicide as a dispersion fuel. Of particular interest was the interaction between the silicide particles and the aluminum matrix, the swelling behavior of the silicide particles, and the maximum volume fraction of silicide particles that could be contained in the aluminum matrix. The first group of experimental 'mini' fuel plates have recently reached the program's goal burnup and are in various stages of examination. Although the results to date indicate some limitations, it appears that within the range of parameters examined thus far the uranium silicide dispersion holds promise for satisfying most of the needs of the RERTR Program. The twelve experimental silicide dispersion fuel plates that were irradiated to approximately their goal exposure show the 30-vol % U 3 Si-Al plates to be in a stage of relatively rapid fission-gas-driven swelling at a fission density of 2 x 10 20 cm -3 . This fuel swelling will likely result in unacceptably large plate-thickness increases. The U 3 Si plates appear to be superior in this respect; however, they, too, are starting to move into the rapid fuel-swelling stage. Analysis of the currently available post irradiation data indicates that a 40-vol % dispersed fuel may offer an acceptable margin to the onset of unstable thickness changes at exposures of 2 x 10 21 fission/cm 3 . The interdiffusion between fuel and matrix

  10. Kr ion irradiation study of the depleted-uranium alloys

    Science.gov (United States)

    Gan, J.; Keiser, D. D.; Miller, B. D.; Kirk, M. A.; Rest, J.; Allen, T. R.; Wachs, D. M.

    2010-12-01

    Fuel development for the reduced enrichment research and test reactor (RERTR) program is tasked with the development of new low enrichment uranium nuclear fuels that can be employed to replace existing high enrichment uranium fuels currently used in some research reactors throughout the world. For dispersion type fuels, radiation stability of the fuel-cladding interaction product has a strong impact on fuel performance. Three depleted-uranium alloys are cast for the radiation stability studies of the fuel-cladding interaction product using Kr ion irradiation to investigate radiation damage from fission products. SEM analysis indicates the presence of the phases of interest: U(Al, Si) 3, (U, Mo)(Al, Si) 3, UMo 2Al 20, U 6Mo 4Al 43 and UAl 4. Irradiations of TEM disc samples were conducted with 500 keV Kr ions at 200 °C to ion doses up to 2.5 × 10 19 ions/m 2 (˜10 dpa) with an Kr ion flux of 10 16 ions/m 2/s (˜4.0 × 10 -3 dpa/s). Microstructural evolution of the phases relevant to fuel-cladding interaction products was investigated using transmission electron microscopy.

  11. Kr ion irradiation study of the depleted-uranium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gan, J., E-mail: Jian.Gan@inl.go [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-6188 (United States); Keiser, D.D. [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-6188 (United States); Miller, B.D. [University of Wisconsin, 1500 Engineering Drive, Madison, WI 53706 (United States); Kirk, M.A.; Rest, J. [Argonne National Laboratory, 9700 South Cass Ave., Argonne, IL 60439 (United States); Allen, T.R. [University of Wisconsin, 1500 Engineering Drive, Madison, WI 53706 (United States); Wachs, D.M. [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-6188 (United States)

    2010-12-01

    Fuel development for the reduced enrichment research and test reactor (RERTR) program is tasked with the development of new low enrichment uranium nuclear fuels that can be employed to replace existing high enrichment uranium fuels currently used in some research reactors throughout the world. For dispersion type fuels, radiation stability of the fuel-cladding interaction product has a strong impact on fuel performance. Three depleted-uranium alloys are cast for the radiation stability studies of the fuel-cladding interaction product using Kr ion irradiation to investigate radiation damage from fission products. SEM analysis indicates the presence of the phases of interest: U(Al, Si){sub 3}, (U, Mo)(Al, Si){sub 3}, UMo{sub 2}Al{sub 20}, U{sub 6}Mo{sub 4}Al{sub 43} and UAl{sub 4}. Irradiations of TEM disc samples were conducted with 500 keV Kr ions at 200 {sup o}C to ion doses up to 2.5 x 10{sup 19} ions/m{sup 2} ({approx}10 dpa) with an Kr ion flux of 10{sup 16} ions/m{sup 2}/s ({approx}4.0 x 10{sup -3} dpa/s). Microstructural evolution of the phases relevant to fuel-cladding interaction products was investigated using transmission electron microscopy.

  12. The size distribution of dissolved uranium in natural waters

    International Nuclear Information System (INIS)

    Mann, D.K.; Wong, G.T.F.

    1987-01-01

    The size distribution of dissolved uranium in natural waters is poorly known. Some fraction of dissolved uranium is known to associate with organic matter which had a wide range of molecular weights. The presence of inorganic colloidal uranium has not been reported. Ultrafiltration has been used to quantify the size distribution of a number of elements, such as dissolved organic carbon, selenium, and some trace metals, in both the organic and/or the inorganic forms. The authors have applied this technique to dissolved uranium and the data are reported here

  13. Formation of uranium based nanoparticles via gamma-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Nenoff, Tina M., E-mail: tmnenof@sandia.gov [Nanoscale Sciences Department, Sandia National Laboratories, P.O. Box 5800, MS-1415, Albuquerque, NM 87185 (United States); Ferriera, Summer R. [Nanoscale Sciences Department, Sandia National Laboratories, P.O. Box 5800, MS-1415, Albuquerque, NM 87185 (United States); Huang, Jianyu [Center for Integrated Nanotechnology, Sandia National Laboratories, P.O. Box 5800, MS-1315, Albuquerque, NM 87185 (United States); Hanson, Donald J. [Department of Hot Cells and Gamma Facilities, Sandia National Laboratories, P.O. Box 5800, MS-1143, Albuquerque, NM 87185 (United States)

    2013-11-15

    Graphical abstract: TEM image of d-U nanoparticles formed in aqueous solution by gamma irradiation. Display Omitted -- Highlights: •d-U nanoparticles were grown in solution by gamma irradiation. •The reaction solution does not exceed 25 °C (room temperature). •Only after multiday exposure to air is there evidence of oxidation of the d-U nanoparticles. •Evidence of d-U alloy nanoparticle formation confirmed by TEM/energy-dispersive X-ray (EDS) analysis. -- Abstract: The ability to fabricate nuclear fuels at low temperatures allows for the production of complex Uranium metal and alloys with minimum volatility of alloy components in the process. Gamma irradiation is a valuable method for the synthesis of a wide range of metal-based nanoparticles. We report on the synthesis via room temperature radiolysis and characterization of uranium (depleted, d-U) metal and uranium–lathanide (d-ULn, Ln = lanthanide surrogates) alloy nanoparticles from aqueous acidic salt solutions. The lanthanide surrogates chosen include La and Eu due to their similarity in ionic size and charge in solution. Detailed characterization results including UV–vis, TEM/HR-TEM, and single particle EDX (elemental analyses) are presented for the room temperature formed nanoparticle products.

  14. Formation of uranium based nanoparticles via gamma-irradiation

    International Nuclear Information System (INIS)

    Nenoff, Tina M.; Ferriera, Summer R.; Huang, Jianyu; Hanson, Donald J.

    2013-01-01

    Graphical abstract: TEM image of d-U nanoparticles formed in aqueous solution by gamma irradiation. Display Omitted -- Highlights: •d-U nanoparticles were grown in solution by gamma irradiation. •The reaction solution does not exceed 25 °C (room temperature). •Only after multiday exposure to air is there evidence of oxidation of the d-U nanoparticles. •Evidence of d-U alloy nanoparticle formation confirmed by TEM/energy-dispersive X-ray (EDS) analysis. -- Abstract: The ability to fabricate nuclear fuels at low temperatures allows for the production of complex Uranium metal and alloys with minimum volatility of alloy components in the process. Gamma irradiation is a valuable method for the synthesis of a wide range of metal-based nanoparticles. We report on the synthesis via room temperature radiolysis and characterization of uranium (depleted, d-U) metal and uranium–lathanide (d-ULn, Ln = lanthanide surrogates) alloy nanoparticles from aqueous acidic salt solutions. The lanthanide surrogates chosen include La and Eu due to their similarity in ionic size and charge in solution. Detailed characterization results including UV–vis, TEM/HR-TEM, and single particle EDX (elemental analyses) are presented for the room temperature formed nanoparticle products

  15. Immobilization of uranium from aqueous solutions by using natural diatomites

    International Nuclear Information System (INIS)

    Mokhambetbakr, Kh.E.; Burkitbaev, M.

    2008-01-01

    In this study, the adsorption of uranium on natural diatomite (as high abundant and low-cost material) obtained from Aktyubinsk (Kazakhstan) has been investigated. The main purpose of this work is the immobilization of uranium from liquid waste by using diatomites. The diatomites under study were subjected to treatment with various conditions. The first sample is the natural sample (D) Natural Diatomite, the second (D H CL) is purified 0,5 N HCl and the third is the Calcined Diatomite (D 9 00). The effects of concentration of uranium, contact time and type of diatomite treatment on the adsorption process were examined.

  16. Bremsstrahlung doses from natural uranium ingots

    International Nuclear Information System (INIS)

    Anderson, J. L.; Hertel, N. E.

    2005-01-01

    In the past, some privately owned commercial facilities in the United States were involved in producing or processing radioactive materials used in the production of atomic weapons. Seven different geometrical objects, representative of the configurations of natural uranium metal potentially encountered by workers at these facilities, are modelled to determine gamma ray and Bremsstrahlung dose rates. The dose rates are calculated using the MCNP5 code and also by using the MICROSHIELD point-kernel code. Both gamma ray and Bremsstrahlung dose rates are calculated and combined to obtain a total dose rate. The two methods were found to be in good agreement despite differences in modelling assumptions and method differences. Computed total dose rates on the surface of these objects ranged from ∼51-84 μSv h -1 and 17-95 μSv h -1 using the MCNP5 and the MICROSHIELD modeling, respectively. The partitioning of the computed dose rates between gamma rays and Bremsstrahlung were the same order of magnitude for each object. (authors)

  17. Bremsstrahlung doses from natural uranium ingots.

    Science.gov (United States)

    Anderson, Jeri L; Hertel, Nolan E

    2005-01-01

    In the past, some privately owned commercial facilities in the United States were involved in producing or processing radioactive materials used in the production of atomic weapons. Seven different geometrical objects, representative of the configurations of natural uranium metal potentially encountered by workers at these facilities, are modelled to determine gamma ray and bremsstrahlung dose rates. The dose rates are calculated using the MCNP5 code and also by using the MICROSHIELD point-kernel code. Both gamma ray and bremsstrahlung dose rates are calculated and combined to obtain a total dose rate. The two methods were found to be in good agreement despite differences in modelling assumptions and method differences. Computed total dose rates on the surface of these objects ranged from approximately 51-84 microSv h(-1) and 17-95 microSv h(-1) using the MCNP5 and the MICROSHIELD modeling, respectively. The partitioning of the computed dose rates between gamma rays and bremsstrahlung were the same order of magnitude for each object.

  18. Determination of irradiated uranium in far-field contaminated areas of Belarus

    International Nuclear Information System (INIS)

    Mironov, V.; Pribylev, S.; Hotchkis, M.; Child, D.

    2006-01-01

    The possibility of using U 236 as an indicator for irradiated uranium is shown. The sensitivity of AMS is high enough for measurements of 236 U/ 238 U ratios down to 10 -9 on micrograms of uranium and therefore for the detection of Chernobyl originated uranium in the remote regions of radioactive fallout. (authors)

  19. Preliminary study of the preparation of uranium 232 by irradiation of protactinium 231

    International Nuclear Information System (INIS)

    Guillot, Ph.

    1965-01-01

    A bibliography about preparation of uranium 232 is done. This even-even isotope of uranium is suitable for radioactive tracer, neutron source through α,n reaction and heat source applications. The irradiation of protactinium 231, the chemical separation and the purification of uranium are studied. (author) [fr

  20. Fluorometric determination of uranium in natural waters

    International Nuclear Information System (INIS)

    Hues, A.D.; Henicksman, A.L.; Ashley, W.H.; Romero, D.

    1977-03-01

    Duplicate 200-μl aliquots of the water samples, as received, are transferred by means of Eppendorf pipettors onto 0.4-g pellets of 2 percent LiF-98 percent NaF flux, contained in platinum dishes. The pellets are dried under heat lamps; then fused over special propane burners. The fused pellets are transferred to a Galvanek-Morrison fluorometer, where they are excited with ultraviolet radiation and the fluorescence is measured. The uranium is calculated by comparing the measured fluorescence with that of other pellets, carried through the same procedure, which contain aliquots of standard uranium solutions. The sensitivity of the method is about 0.2 ppB of uranium, and the precision is approximately 15 relative percent in the 0.2- to 10-ppB uranium concentration range

  1. Uranium

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  2. Crystallographic study of the tempering by irradiation of cold-worked uranium (1960); Etude cristallographique du revenu de l'uranium ecroui par irradiation (1960)

    Energy Technology Data Exchange (ETDEWEB)

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

    1960-07-01

    We have studied the phenomenon of the tempering of cold-worked uranium under the action of irradiation by observing the narrowing of the (114) and (133) X-ray diffraction lines as a function of the irradiation level. Simultaneously we have studied the broadening of the 114 line of a recrystallised uranium as a function of the irradiation level. The irradiation temperature was always less than 60 deg. C. Of these two processes, the first is the fastest. We have observed a saturation of the irradiation tempering for a flux of 10{sup 18} n/cm{sup 2}; we deduce from this the dimensions of the volume perturbed by one fission atom to be 10{sup -17} cm{sup 3}. (author) [French] Nous avons etudie le phenomene de revenu par irradiation d'echantillons d'uranium ecroui, en observant l'affinement des raies de diffraction de rayons X (114) et (133) en fonction du taux d'irradiation. Parallelement nous avons etudie l'elargissement de la raie (114 ) d'un uranium recristallise en fonction du taux d'irradiation. La temperature d'irradiation est toujours restee inferieure a 60 deg. C. De ces deux processus le premier est le plus rapide. Nous avons observe une saturation du revenu par irradiation pour un flux de 10{sup 18} n/cm{sup 2}; on en deduit une valeur du volume de la perturbation creee par un atome de fission egale a 10{sup -17} cm{sup 3}. (auteur)

  3. Irradiation of TZM: Uranium dioxide fuel pin at 1700 K

    Science.gov (United States)

    Mcdonald, G. E.

    1973-01-01

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

  4. Depleted and natural uranium: chemistry and toxicological effects.

    Science.gov (United States)

    Craft, Elena; Abu-Qare, Aquel; Flaherty, Meghan; Garofolo, Melissa; Rincavage, Heather; Abou-Donia, Mohamed

    2004-01-01

    Depleted uranium (DU) is a by-product from the chemical enrichment of naturally occurring uranium. Natural uranium is comprised of three radioactive isotopes: (238)U, (235)U, and (234)U. This enrichment process reduces the radioactivity of DU to roughly 30% of that of natural uranium. Nonmilitary uses of DU include counterweights in airplanes, shields against radiation in medical radiotherapy units and transport of radioactive isotopes. DU has also been used during wartime in heavy tank armor, armor-piercing bullets, and missiles, due to its desirable chemical properties coupled with its decreased radioactivity. DU weapons are used unreservedly by the armed forces. Chemically and toxicologically, DU behaves similarly to natural uranium metal. Although the effects of DU on human health are not easily discerned, they may be produced by both its chemical and radiological properties. DU can be toxic to many bodily systems, as presented in this review. Most importantly, normal functioning of the kidney, brain, liver, and heart can be affected by DU exposure. Numerous other systems can also be affected by DU exposure, and these are also reviewed. Despite the prevalence of DU usage in many applications, limited data exist regarding the toxicological consequences on human health. This review focuses on the chemistry, pharmacokinetics, and toxicological effects of depleted and natural uranium on several systems in the mammalian body. A section on risk assessment concludes the review.

  5. Data feature World natural Uranium production 1992

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    NUKEM estimates that world uranium production fell more than 13% last year, from 40,729 tonnes U [106 million lbs U308] in 1991 to 35,363 tonnes U [92 million lbs U308] in 1992. Production fell in both the Western World and non-Western World. How much of demand was met by production? World uranium production in 1992 amounted to about 65% of reactor consumption. That's assuming that reactor demand of the non-Western World has not changed much from the Uranium Institute's estimate for 1991. Civilian stockpiles are being drawn down on a massive scale while the world waits to see what will become of the military stockpiles that could soon enter the global supply picture

  6. Uranium doping and neutron irradiation of Bi-2223 superconduction tapes for improved critical current density

    International Nuclear Information System (INIS)

    Moss, S.D.; Wang, W.G.; Dou, S.X.; Weinstein, R.

    1998-01-01

    It is demonstrated that a combination of neutron irradiation with uranium doping introduce fission tracks through a Bi-2223 tape which act as effective pinning centres, leading to a substantial increase in critical current. Preliminary data suggests that the combination of uranium doping and neutron irradiation produces improved flux pinning in Bi-2223 tapes over neutron irradiation alone. Before irradiation, SEM, DTA and XRD analyses were performed on the tapes. Both before and after irradiation the trapped maximum magnetic flux was measured at 77K. Before neutron irradiation, uranium doping has no effect on critical current. Preliminary SEM data suggested that the uranium is homogeneously distributed throughout the oxide core of the tape. The presence of 2212 and other secondary phases in the doped tapes suggest further refinement of the sintering procedure is necessary. (authors)

  7. Natural uranium lattice in heavy water

    International Nuclear Information System (INIS)

    Girard, Y.; Koechlin, J.C.; Moreau, J.; Naudet, R.

    1959-01-01

    all solid bars are considered and n an d the effective integrals are adjusted then a system of transposition of these results to more complex bars is sought. In the second step, one is compelled to improve the system in studying in greater detail each factor of the calculation of the lattice. A satisfactory interpretation of the results leads definitively to methods of calculation applicable to the most varied types of natural uranium-heavy water lattices. Attention has been given to results obtained in other countries, particularly in Canada. (author) [fr

  8. Study on the uranium-cerium extraction and his application to the treatment of irradiated uranium

    International Nuclear Information System (INIS)

    Lobao, Afonso dos Santos Tome

    1979-01-01

    It was made a study on the behavior of uranium and cerium(IV) extraction, using the latter element as a plutonium simulator in a flowsheet of the treatment of irradiated uranium. Cerium(IV) was used under the same conditions as a plutonium in the Purex process because the admitted similar properties. An experimental work was initiated to determine the equilibrium curves of uranium, under the following conditions: concentration of 1 to 20 g U/1 and acidity varying from 1 to 5M in HNO 3 . Other parameters studied were the volumetric ratio of the phases and the influence of the concentration of TBP (tri-n-butyl phosphate). To guarantee the cerium(IV) extraction, the diluent (varsol) was previously treated with 10% potassium dichromate in perchloric acid, potassium permanganate in 1M sulphuric acid and concentrated sulphuric acid at 70 deg to eliminate reducing compounds. The results obtained for cerium extraction, allowed a better understanding of its behavior in solution. The results permitted to conclude that the decontamination for cerium are very high in the first Purex extraction cycle. The easy as cerium(IV) is reduced to the trivalent state contributes a great deal to its decontamination. (author)

  9. Separation of heavier rare earths from neutron irradiated uranium targets

    International Nuclear Information System (INIS)

    Bhargava, V.K.; Rao, V.K.; Marathe, S.G.; Sahakundu, S.M.; Iyer, R.H.

    1978-01-01

    A radiochemical method is described for the separation of heavier rare earths from the fission of uranium. The method is particularly suitable for the separation of low yield (10sup(-5)%-10sup(-7)%), highly asymmetric rare earth fission products viz. sup(179,177)Lu, sup(175)Yb, sup(173)Tm, sup(172,171)Er, sup(167)Ho and sup(161,160)Tb in the neutron induced fission of natural and depleted uranium targets. Additional separation steps have been incorporated for decontamination from sup(239)Np (an activation product) and sup(93-90)Y (a high fission-yield product) which show similar chemical behaviour to rare earths. Separation of individual rare earths is achieved by a cation exchange method performed at 80 deg C by elution with α-hydroxyisobutyric acid (α-HIBA). (author)

  10. The measurement of natural uranium in urine by fluorometry

    International Nuclear Information System (INIS)

    Kramer, G.H.; Johnson, J.R.; Green, W.

    1984-02-01

    The fluorometric method of measuring natural uranium in urine that is currently used by the Bioassay Laboratory at Chalk River Nuclear Laboratories has been tested, optimized and documented. The method, which measures the fluorescence of uranium in a fused sodium fluoride pellet, has been shown to be quench independent and is routinely used to measure uranium concentrations in the range of 1 μg/L to 90 μg/L. The fluorimeter has a dynamic range of 0.2 μg/L to 200 μg/L

  11. Microbiological decontamination of natural honey by irradiation

    Science.gov (United States)

    Migdał, W.; Owczarczyk, H. B.; K ȩdzia, B.; Hołderna-K ȩdzia, E.; Madajczyk, D.

    2000-03-01

    Degree of microbiological decontamination, organoleptic and physico-chemical properties of natural honeys were investigated after radiation treatment. Seven kinds of honeys were irradiated with the beams of 10 MeV electrons from a 10 kW linear accelerator "Elektronika 10-10" at the dose 10 kGy. It was shown, that after irradiation, the total count of aerobic and anaerobic bacteria and moulds decrease by 99%. The antibiotic value in investigated honeys increased in turn from 1.67 to 2.67 after irradiation. Such factors and parameters of investigated honeys as their consistency, content of water and saccharose, acidity, the diastase and 5-HMF values were not changed significantly after irradiation. Decontamination by irradiation is a process which allows us to obtain high microbiological purity of honeys. It is especially needed, when honeys are used in surgical treatment of injuries and in nutrition of babies with food deficiency.

  12. Microbiological decontamination of natural honey by irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Migdal, W.; Owczarczyk, H.B.; Kedzia, B.; Holderna-Kedzia, E.; Madajczyk, D

    2000-03-01

    Degree of microbiological decontamination, organoleptic and physico-chemical properties of natural honeys were investigated after radiation treatment. Seven kinds of honeys were irradiated with the beams of 10 MeV electrons from a 10 kW linear accelerator ''Elektronika 10-10'' at the dose 10 kGy. It was shown, that after irradiation, the total count of aerobic and anaerobic bacteria and moulds decrease by 99%. The antibiotic value in investigated honeys increased in turn from 1.67 to 2.67 after irradiation. Such factors and parameters of investigated honeys as their consistency, content of water and saccharose, acidity, the diastase and 5-HMF values were not changed significantly after irradiation. Decontamination by irradiation is a process which allows us to obtain high microbiological purity of honeys. It is especially needed, when honeys are used in surgical treatment of injuries and in nutrition of babies with food deficiency.

  13. Microbiological decontamination of natural honey by irradiation

    International Nuclear Information System (INIS)

    Migdal, W.; Owczarczyk, H.B.; Kedzia, B.; Holderna-Kedzia, E.; Madajczyk, D.

    2000-01-01

    Degree of microbiological decontamination, organoleptic and physico-chemical properties of natural honeys were investigated after radiation treatment. Seven kinds of honeys were irradiated with the beams of 10 MeV electrons from a 10 kW linear accelerator ''Elektronika 10-10'' at the dose 10 kGy. It was shown, that after irradiation, the total count of aerobic and anaerobic bacteria and moulds decrease by 99%. The antibiotic value in investigated honeys increased in turn from 1.67 to 2.67 after irradiation. Such factors and parameters of investigated honeys as their consistency, content of water and saccharose, acidity, the diastase and 5-HMF values were not changed significantly after irradiation. Decontamination by irradiation is a process which allows us to obtain high microbiological purity of honeys. It is especially needed, when honeys are used in surgical treatment of injuries and in nutrition of babies with food deficiency

  14. Field technique for the measurement of uranium in natural waters

    Energy Technology Data Exchange (ETDEWEB)

    Robbins, J C [Scintrex Ltd., Concord, Ontario

    1978-05-01

    An analytical method suitable for field determination of trace levels of uranium in natural waters is described. Laser UV radiation causes persistent fluorescence of a uranyl complex. Electronic gating substantially rejects detection of short-lived natural organic matter fluorescence. Further work is required on effects of interferences in samples with complex matrices and interpretative aids such as concurrent conductivity and organic content measurements.

  15. Influence of Uranium on Bacterial Communities: A Comparison of Natural Uranium-Rich Soils with Controls

    Science.gov (United States)

    Mondani, Laure; Benzerara, Karim; Carrière, Marie; Christen, Richard; Mamindy-Pajany, Yannick; Février, Laureline; Marmier, Nicolas; Achouak, Wafa; Nardoux, Pascal; Berthomieu, Catherine; Chapon, Virginie

    2011-01-01

    This study investigated the influence of uranium on the indigenous bacterial community structure in natural soils with high uranium content. Radioactive soil samples exhibiting 0.26% - 25.5% U in mass were analyzed and compared with nearby control soils containing trace uranium. EXAFS and XRD analyses of soils revealed the presence of U(VI) and uranium-phosphate mineral phases, identified as sabugalite and meta-autunite. A comparative analysis of bacterial community fingerprints using denaturing gradient gel electrophoresis (DGGE) revealed the presence of a complex population in both control and uranium-rich samples. However, bacterial communities inhabiting uraniferous soils exhibited specific fingerprints that were remarkably stable over time, in contrast to populations from nearby control samples. Representatives of Acidobacteria, Proteobacteria, and seven others phyla were detected in DGGE bands specific to uraniferous samples. In particular, sequences related to iron-reducing bacteria such as Geobacter and Geothrix were identified concomitantly with iron-oxidizing species such as Gallionella and Sideroxydans. All together, our results demonstrate that uranium exerts a permanent high pressure on soil bacterial communities and suggest the existence of a uranium redox cycle mediated by bacteria in the soil. PMID:21998695

  16. Examination of uranium recovery technique from sea water using natural components for adsorbent

    International Nuclear Information System (INIS)

    Tanaka, Nobuyuki; Masaki, Hiroyuki; Shimizu, Takao; Tokiwai, Moriyasu

    2010-01-01

    In this study, we investigated the potency of natural components as adsorbent for uranium recovery from seawater. In addition, cost evaluation of uranium recovery from seawater using natural components for adsorbents was performed. Furthermore, new ideas on reservation system of adsorbents at sea area were proposed. Several poly-phenols were selected as adsorbent reagents, then they were adsorbed on the support such as cotton fiber by several methods as the followings; chemical syntheses, electrical beam irradiation, and traditional dyeing. As a result, the adsorbent made by traditional dyeing method using gallnut tannin as natural component, was showed high performance for uranium recovery from seawater on only the first. It was evaluated that traditional dyeing method had also advantage in the manufacturing cost, comparing with earlier method. Additionally, it was considered that reservation system of adsorbent at sea was able to be simplified compared with earlier system. Consequently, uranium recovery from sea water using natural components as adsorbent proposed in this study had a potency of practical use. (author)

  17. Immobilization of uranium in contaminated soil by natural apatite addition

    International Nuclear Information System (INIS)

    Mrdakovic Popic, Jelena; Stojanovic, Mirjana; Milosevic, Sinisa; Iles, Deana; Zildzovic, Snezana

    2007-01-01

    Available in abstract form only. Full text of publication follows: The goal of this study was to evaluate the effectiveness of Serbian natural mineral apatite as soil additive for reducing the migration of uranium from contaminated sediments. In laboratory study we investigated the sorption properties of domestic apatite upon different experimental conditions, such as pH, adsorbent mass, reaction period, concentration of P 2 O 5 in apatite, solid/liquid ratio. In second part of study, we did the quantification of uranium in soil samples, taken from uranium mine site 'Kalna', by sequential extraction method. The same procedure was, also, used for uranium determination in contaminated soil samples after apatite addition, in order to determine the changes in U distribution in soil fraction. The obtained results showed the significant level of immobilization (96.7%) upon certain conditions. Increase of %P 2 O 5 in apatite and process of mechano-chemical activation led to increase of immobilization capacity from 17.50% till 91.64%. The best results for uranium binding were obtained at pH 5.5 and reaction period 60 days (98.04%) The sequential extraction showed the presence of uranium (48.2%) in potentially available soil fractions, but with the apatite addition uranium content in these fractions decreased (30.64%), what is considering environmental aspect significant fact. In situ immobilization of radionuclide using inexpensive sequestering agents, such as apatite, is very adequate for big contaminated areas of soil with low level of contamination. This investigation study on natural apatite from deposit 'Lisina' Serbia was the first one of this type in our country. Key words: apatite, uranium, immobilization, soil, contamination. (authors)

  18. Irradiation of an uranium silicide prototype in RA-3 reactor

    International Nuclear Information System (INIS)

    Calabrese, R.; Estrik, G.; Notari, C.

    1996-01-01

    The factibility of irradiation of an uranium silicide (U 3 Si 2 ) prototype in the RA-3 reactor was studied. The standard RA-3 fuel element uses U 3 O 8 as fissible material. The enrichment of both standard and prototype is the same: 20% U 235 and also the frame geometry and number of plates is identical. The differences are in the plate dimensions and the fissile content which is higher in the prototype. The cooling conditions of the core allow the insertion of the prototype in any core position, even near the water trap, if the overall power is kept below 5Mw. Nevertheless, the recommendation was to begin irradiation near the periphery and later on move the prototype towards more central positions in order to increase the burnup rate. The prototype was effectively introduced in a peripheral position and the thermal fluxes were measured between plates with the foil activation technique. These were also evaluated with the fuel management codes and a reasonable agreement was found. (author). 5 refs., 3 figs., 3 tabs

  19. Emergency exposure levels for natural uranium

    International Nuclear Information System (INIS)

    Spoor, N.L.; Harrison, N.T.

    1980-12-01

    An attempt is made to identify the inhalation hazards associated with the over-exposure of workers and of the general public, following an accidental release of uranium hexafluoride. Maximum emergency concentrations are recommended for periods of 10, 30, and 60 minutes. The quantitative aspect of the assessment is considered in the context of the development of exposure standards for chemical substances and this facilitates the derivation of levels which are compatible with occupational and public health experience and attainable by management, and to which most workers and members of the general public may be exposed without adverse effect. The radiological implications are also considered. (author)

  20. Irradiation tests of 99Mo isotope production targets employing uranium metal foils

    International Nuclear Information System (INIS)

    Hofman, G.L.; Wiencek, T.C.; Wood, E.L.; Snelgrove, J.L.; Suripto, A.; Nasution, H.; Lufti-Amin, D.; Gogo, A.

    1996-01-01

    Most of the world's supply of 99 mTc for medical purposes is currently produced from the decay of 99 Mo derived from the fissioning of high-enriched uranium (HEU). Substitution of low-enriched uranium (LEU) metal foils for the HEU UO 2 used in current target designs will allow equivalent 99 Mo yields with little change in target geometries. Substitution of uranium metal for uranium alloy and aluminide in other target designs will also allow the conversion of HEU to LEU. Several uranium-metal-foil targets have been fabricated at ANL and irradiated to prototypic burnup in the Indonesian RSG-GAS reactor. Postirradiation examination of the initial test indicated that design modifications were required to allow the irradiated foil to be removed for chemical processing. The latest test has shown good irradiation behavior, satisfactory dismantling and foil removal when the U-foil is separated from its containment by metallic, fission-recoil absorbing barriers. (author)

  1. Irradiation tests of 99Mo isotope production targets employing uranium metal foils

    International Nuclear Information System (INIS)

    Hofman, G.L.; Wiencek, T.C.; Wood, E.L.; Snelgrove, J.L.; Suripto, A.; Nasution, H.; Lufti-Amin, D.; Gogo, A.

    1996-01-01

    Most of the world's supply of 99m Tc for medical purposes is currently produced form the decay of 99 Mo derived from the fissioning of high-enriched uranium (HEU). Substitution of low-enriched uranium (LEU) metal foils for the HEU UO 2 used in current target designs will allow equivalent 99 Mo yields with little change in target geometries. Substitution of uranium metal for uranium alloy and aluminide in other target designs will also allow the conversion of HEU to LEU. Several uranium-metal-foil targets have been fabricated at ANL and irradiated to prototypic burnup in the Indonesian RSG-GAS reactor. Postirradiation examination of the initial test indicated that design modifications were required to allow the irradiated foil to be removed for chemical processing. The latest test has shown good irradiation behavior, satisfactory dismantling and foil removal when the U-foil is separated from its containment by metallic, fission-recoil absorbing barriers

  2. Natural uranium toxicology - evaluation of internal contamination in man

    International Nuclear Information System (INIS)

    Chalabreysse, J.

    1968-01-01

    After reminding the physical and chemical properties of natural uranium which might affect its toxicology, a comprehensive investigation upon natural uranium metabolism and toxicity and after applying occupational exposure standards to this particular poison, it has been determined, from accident reports and human experience reported in the related literature, a series of formulae obtained by theoretical mathematical development giving principles for internal contamination monitoring and disclosure by determining uranium in the urine of occupationally exposed individuals. An assay is performed to determine individual internal contamination according to the various contamination cases. The outlined purposes, mainly practical, required some options and extrapolations. The proposed formula allows a preliminary approach and also to determine shortly a contamination extent or to discuss the systematical urinalysis results as compared with individual radio-toxicology monitoring professional standards. (author) [fr

  3. The Bare Critical Assembly of Natural Uranium and Heavy Water

    Energy Technology Data Exchange (ETDEWEB)

    Popovic, D [Boris Kidric Institute of Nuclear Sciences, Vinca, Belgrade (Yugoslavia)

    1958-07-01

    The first reactor built in Yugoslavia was the bare zero energy heavy water and natural uranium assembly at the Boris Kidric Institute of Nuclear Sciences, Belgrade. The reactor went critical on April 29, 1958. The possession of four tons of natural uranium metal and the temporary availability of seven tons of heavy water encouraged the staff of the Institute to build a critical assembly. A critical assembly was chosen, rather than high flux reactor, because the heavy water was available only temporarily. Besides, a 10 MW, enriched uranium, research reactor is being built at the same Institute and should be ready for operation late this year. It was supposed that the zero energy reactor would provide experience in carrying out critical experiments, operational experience with nuclear reactors, and the possibility for an extensive program in reactor physics. (author)

  4. 226Ra and natural uranium in egyptian bottled mineral waters

    International Nuclear Information System (INIS)

    Higgy, R.H.

    2000-01-01

    Concentration levels of 226 Ra and natural uranium have been analysed bottled mineral water commercially available in egypt. 226 Ra was determined by applying a chemical procedure in which Ra was coprecipitated with Ba as sulphate. The precipitate was then dissolved with EDTA and then measured by liquid scintillation system, after mixing with a scintillation cocktail. Natural uranium was determined by applying a chemical procedure for uranium extraction using MIBK and then measured using laser fluorimeter system. The concentration values obtained were compared with concentrations reported by other countries and with reference values accepted for drinking water. Based on the consumption rate and the measured concentrations, the collective committed effective doses were calculated. In addition, Ca, Mg and Na were measured using Icp system and compared with some worldwide values

  5. Preliminary study of the preparation of uranium 232 by irradiation of protactinium 231; Etude preliminaire a la preparation d'uranium 232 par irradiation de protactinium 231

    Energy Technology Data Exchange (ETDEWEB)

    Guillot, Ph. [Commissariat a l' Energie Atomique, Fontenay aux Roses (France). Centre d' Etudes Nucleaires

    1965-07-01

    A bibliography about preparation of uranium 232 is done. This even-even isotope of uranium is suitable for radioactive tracer, neutron source through {alpha},n reaction and heat source applications. The irradiation of protactinium 231, the chemical separation and the purification of uranium are studied. (author) [French] Une etude bibliographique de la preparation d'uranium 232 a ete effectuee. Cet isotope pair-pair de l'uranium peut etre utilise en tant que traceur, source d'energie et source de neutrons, lorsqu'il est melange a un element leger tel le beryllium. Une etude du taux de formation des isotopes produits, lors de l'irradiation du protactinium 231 - une des manieres d'obtenir l'uranium 232 - a ete faite a l'aide d'un programme passe sur ordinateur. Les problemes poses par la separation chimique et la purification de l'uranium ont ete egalement envisages dans ce rapport. (auteur)

  6. Production of annular blanks for Mo-99 using natural uranium, LEU uranium, nickel and structural Al-3003 plates

    International Nuclear Information System (INIS)

    Lisboa, J.R.; Barrera, M.E.; Marin, J.

    2010-01-01

    The Tc-99m radioisotope for medical use is the one most used in nuclear medicine worldwide. In Chile the Tc-99m is applied in more than 90% of nuclear medicine studies. In order to supply the whole country with this radioisotope, in 2005-2007 the CCHEN developed its own production of Tc-99m generators from Mo-99 imported from Canada, which are prepared with the activity needed by the Chilean hospitals and clinics. As of 2007 Mo-99 was no longer imported, and since then the Tc-99m is produced only by neutron activation of the Mo. The present challenge is to produce Mo-99 by irradiating blanks that contain enriched uranium foils, with locally produced LEU. The annular blank consists of 2 concentric tubes of A1-3003 structural aluminum that, in an interior annular space, contain a LEU foil, covered on both sides by a nickel foil. This work presents the development of the production technology for annular blanks using natural uranium and U-325 enriched uranium. The structural components are made with A1-3003 aluminum alloy, the foils are 13 grams of uranium measuring 100 x 50 mm and 120-150 μ thick. The blank was assembled using a methodology to control, adapt and assemble the blank's different internal components. A foil of natural uranium and LEU uranium, and a nickel foil are included, used as a barrier for the escape of fission products. During the blank's expansion, for analysis alcohol as lubricant was used, allowing the expander to move smoothly through the inside of the blank. The blank was sealed by TIG welding with a pulsed AC current and a mixture of Ar-5% He gases. Two methods were used for the water tightness test; for high escape levels the temperature was used as a promoter of the ΔP provided by hot water and liquid nitrogen, for low escape levels high vacuum technology was used where the ΔP is provided by a high pressure helium atmosphere. The technology for the production of annular LEU blanks was achieved by applying innovations to technologies

  7. Micromechanical simulation of Uranium dioxide polycrystalline aggregate behaviour under irradiation

    International Nuclear Information System (INIS)

    Pacull, J.

    2011-02-01

    In pressurized water nuclear power reactor (PWR), the fuel rod is made of dioxide of uranium (UO 2 ) pellet stacked in a metallic cladding. A multi scale and multi-physic approaches are needed for the simulation of fuel behavior under irradiation. The main phenomena to take into account are thermomechanical behavior of the fuel rod and chemical-physic behavior of the fission products. These last years one of the scientific issue to improve the simulation is to take into account the multi-physic coupling problem at the microscopic scale. The objective of this ph-D study is to contribute to this multi-scale approach. The present work concerns the micro-mechanical behavior of a polycrystalline aggregate of UO 2 . Mean field and full field approaches are considered. For the former and the later a self consistent homogenization technique and a periodic Finite Element model base on the 3D Voronoi pattern are respectively used. Fuel visco-plasticity is introduced in the model at the scale of a single grain by taking into account specific dislocation slip systems of UO 2 . A cohesive zone model has also been developed and implemented to simulate grain boundary sliding and intergranular crack opening. The effective homogenous behaviour of a Representative Volume Element (RVE) is fitted with experimental data coming from mechanical tests on a single pellet. Local behavior is also analyzed in order to evaluate the model capacity to assess micro-mechanical state. In particular, intra and inter granular stress gradient are discussed. A first validation of the local behavior assessment is proposed through the simulation of intergranular crack opening measured in a compressive creep test of a single fuel pellet. Concerning the impact of the microstructure on the fuel behavior under irradiation, a RVE simulation with a representative transient loading of a fuel rod during a power ramp test is achieved. The impact of local stress and strain heterogeneities on the multi

  8. 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

  9. The development of uranium foil farication technology utilizing twin roll method for Mo-99 irradiation target

    CERN Document Server

    Kim, C K; Park, H D

    2002-01-01

    MDS Nordion in Canada, occupying about 75% of global supply of Mo-99 isotope, has provided the irradiation target of Mo-99 using the rod-type UAl sub x alloys with HEU(High Enrichment Uranium). ANL (Argonne National Laboratory) through co-operation with BATAN in Indonesia, leading RERTR (Reduced Enrichment for Research and Test Reactors) program substantially for nuclear non-proliferation, has designed and fabricated the annular cylinder of uranium targets, and successfully performed irradiation test, in order to develop the fabrication technology of fission Mo-99 using LEU(Low Enrichment Uranium). As the uranium foils could be fabricated in laboratory scale, not in commercialized scale by hot rolling method due to significant problems in foil quality, productivity and economic efficiency, attention has shifted to the development of new technology. Under these circumstances, the invention of uranium foil fabrication technology utilizing twin-roll casting method in KAERI is found to be able to fabricate LEU or...

  10. Radiation damage in uranium under electron irradiation of energies up to 20 MeV

    International Nuclear Information System (INIS)

    Emets, N.L.; Zelenskij, V.F.; Kuz'menko, V.A.; Ranyuk, Yu.N.; Reznichenko, Eh.A.; Shilyaev, B.A.; Yamnitskij, V.A.

    1980-01-01

    The problem of conservation of primary radiation-induced defects in uranium irradiated by electrons with the energy exceeding photo fission threshold is considered. Calculation of uranium burnout is carried out. Calculations are conducted by the method of mathematical simulation, using some nuclear models; development of electromagnetic cascade in uranium, photofission process, elastic and inelastic electron scattering, as well as some secondary processes are taken into account. Proved is the fact of anomalous growth of uranium under electron irradiation, registered earlier experimentally. It is shown, that in case of acquiring the value Ed=15 eV radiation uranium growth at low levels of burnout can be explained by the complete capture of all the primary radiationn-induced defects into dislocation loops [ru

  11. 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.

  12. 10 CFR 40.66 - Requirements for advance notice of export shipments of natural uranium.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Requirements for advance notice of export shipments of natural uranium. 40.66 Section 40.66 Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING OF SOURCE... natural uranium. (a) Each licensee authorized to export natural uranium, other than in the form of ore or...

  13. Depleted uranium (DU) mobility in the natural environment

    International Nuclear Information System (INIS)

    Ragnarsdottir, K.V.

    2002-01-01

    In 1999 the Balkan's conflict lead NATO war planes to leave 10x10 3 kg of depleted uranium (DU) in the environment of Kosovo and neighbouring states (UNEP, 2001). DU behaves in the same manner in the environment as natural uranium and it can be traced with isotopic analysis due to the fact that DU has the isotopic composition of 0.2% 235 U and 99.8% 2 38 U as opposed to natural uranium which has 0.7% 2 35 U and 99.3% 2 38 U. DU is a waste product of the nuclear industry which enrich nuclear fuel by 2 35 U. Large stock piles of DU therefore exist in countries that produce nuclear energy and/or nuclear weapons. The DU is given to the weapons industry for free (or cheap) and has been a popular choice for armour penetrating arsenal due to the high density of uranium (19 g cm -3 ) and therefore its high penetrating power. Indeed the arsenal used in Kosovo consisted of DU penetrators that were shot from A-10 aeroplanes. They weigh roughly 300 g and have the shape of a fat 9 cm long pencil. (author)

  14. 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)

  15. Migration of uranium daughter radionuclides in natural sediments

    International Nuclear Information System (INIS)

    Colley, S.; Thomson, J.

    1991-01-01

    An irregular concentration/depth profile of uranium in deep-sea turbidities, previously elucidated, has been exploited to obtain in-situ effective diffusion coefficients for the long-lived members of the 238 U natural series. The findings are relevant to the assessment of deep-sea sediments as potential repositories for high-level radioactive waste, because waste actinides decay through the same chains of daughter radionuclides as natural actinides. This work was part of the CEC Mirage project-Second phase, Natural analogues research area

  16. Aspects on optimization of natural uranium fuel utilization in heavy water reactors

    International Nuclear Information System (INIS)

    1978-08-01

    This paper is dealing with a possibility to decrease the natural uranium consumption of CANDU PHWR using the once-through cycle. This possibility is based on the utilization of slightly enriched uranium. The optimal two-zone structure of a reactor using natural uranium is found out. The optimal criterium is the maximization of the burnup (equivalent to minimization of uranium requirements) with a constraint on power density radial uniformity factor. As regards the enriched uranium, the optimal enrichment and the two-zone structure of a reactor which minimizes the natural uranium requirement with constraints on uniformity factor and maximum burnup are established. Corresponding to a maximum burnup of 16,000 MWd/t and 1% enrichment, the natural uranium requirement is found to be 10% less than that of the natural uranium reactor

  17. Natural uranium fueled light water moderated breeding hybrid power reactors

    International Nuclear Information System (INIS)

    Greenspan, E.; Schneider, A.; Misolovin, A.; Gilai, D.; Levin, P.

    The feasibility of fission-fusion hybrid reactors based on breeding light water thermal fission systems is investigated. The emphasis is on fuel-self-sufficient (FSS) hybrid power reactors that are fueled with natural uranium. Other LWHRs considered include FSS-LWHRs that are fueled with spent fuel from LWRs, and LWHRs which are to supplement LWRs to provide a tandem LWR-LWHR power economy that is fuel-self-sufficient

  18. Natural uranium metallic fuel elements: fabrication and operating experience

    International Nuclear Information System (INIS)

    Hammad, F.H.; Abou-Zahra, A.A.; Sharkawy, S.W.

    1980-01-01

    The main reactor types based on natural uranium metallic fuel element, particularly the early types, are reviewed in this report. The reactor types are: graphite moderated air cooled, graphite moderated gas cooled and heavy water moderated reactors. The design features, fabrication technology of these reactor fuel elements and the operating experience gained during reactor operation are described and discussed. The interrelation between operating experience, fuel design and fabrication was also discussed with emphasis on improving fuel performance. (author)

  19. Components of natural irradiation and local variations

    International Nuclear Information System (INIS)

    Bouville, A.

    1985-01-01

    The purpose of this paper is to give an overview of the natural radiation environment and of the human exposures from natural radiation sources. Any form of life on earth is unavoidably associated with exposure to natural radiation. There are two kinds of sources of natural radiation: sources in the extraterrestrial environment (i.e. cosmic rays); terrestrial sources (i.e. the radioactive substances in the earth's crust). Both types of sources irradiate the human body from outside but also from inside as naturally occuring nuclides are taken up into the body through normal physiological pathways. When living in a natural environment, man is exposed to all these sources. On the average, the exposure from natural radiation is much greater than the exposures from artificial sources. The extraterrestrial sources and the terrestrial sources will be considered in succession. Some emphasis will be placed on the internal exposures but external exposures will also be discussed. The exposures will be expressed in terms of effective dose equivalent, which is a quantity assumed to be proportional to the radiation risk. Most of the information will be taken from the latest UNSCEAR report, which periodically reviews the information on the sources and effects of ionizing radiation [fr

  20. Internal irradiation by radon daughters in Bulgarian uranium mines over the period 1956-1990

    International Nuclear Information System (INIS)

    Dimitrov, M.; Presiyanov, D.

    1993-01-01

    The results of over 30-years' radiation monitoring in Bulgarian uranium mines are summed up in retrospect. The overall organization and the parameters monitored during the different periods are discussed. A radiological characteristic of the working environment is presented which includes radon and its decay products. The internal irradiation levels during different time periods and in different mines have been estimated. The health costs of uranium mining in Bulgaria are discussed and conclusions and recommendations for radiological control are made. (author)

  1. Improved locations of reactivity devices in future CANDU reactors fuelled with natural uranium or enriched fuels

    International Nuclear Information System (INIS)

    Boczar, P.G.; Van Dyk, M.T.

    1987-02-01

    A new configuration of reactivity devices is proposed for future CANDU reactors which improves the core characteristics with enriched fuels, while still allowing the use of natural uranium fuel. Physics calculations for this new configuration are presented for four fuel types: natural uranium, mixed plutonium - uranium oxide (MOX) having a burnup of 21 MWd/kg, and slightly enriched uranium (SEU) having burnups of either 21 or 31 MWd/kg

  2. Uranium Biomineralization By Natural Microbial Phosphatase Activities in the Subsurface

    Energy Technology Data Exchange (ETDEWEB)

    Taillefert, Martial [Georgia Tech Research Corporation, Atlanta, GA (United States)

    2015-04-01

    This project investigated the geochemical and microbial processes associated with the biomineralization of radionuclides in subsurface soils. During this study, it was determined that microbial communities from the Oak Ridge Field Research subsurface are able to express phosphatase activities that hydrolyze exogenous organophosphate compounds and result in the non-reductive bioimmobilization of U(VI) phosphate minerals in both aerobic and anaerobic conditions. The changes of the microbial community structure associated with the biomineralization of U(VI) was determined to identify the main organisms involved in the biomineralization process, and the complete genome of two isolates was sequenced. In addition, it was determined that both phytate, the main source of natural organophosphate compounds in natural environments, and polyphosphate accumulated in cells could also be hydrolyzed by native microbial population to liberate enough orthophosphate and precipitate uranium phosphate minerals. Finally, the minerals produced during this process are stable in low pH conditions or environments where the production of dissolved inorganic carbon is moderate. These findings suggest that the biomineralization of U(VI) phosphate minerals is an attractive bioremediation strategy to uranium bioreduction in low pH uranium-contaminated environments. These efforts support the goals of the SBR long-term performance measure by providing key information on "biological processes influencing the form and mobility of DOE contaminants in the subsurface".

  3. Reactivity of Uranium and Ferrous Iron with Natural Iron Oxyhydroxides.

    Science.gov (United States)

    Stewart, Brandy D; Cismasu, A Cristina; Williams, Kenneth H; Peyton, Brent M; Nico, Peter S

    2015-09-01

    Determining key reaction pathways involving uranium and iron oxyhydroxides under oxic and anoxic conditions is essential for understanding uranium mobility as well as other iron oxyhydroxide mediated processes, particularly near redox boundaries where redox conditions change rapidly in time and space. Here we examine the reactivity of a ferrihydrite-rich sediment from a surface seep adjacent to a redox boundary at the Rifle, Colorado field site. Iron(II)-sediment incubation experiments indicate that the natural ferrihydrite fraction of the sediment is not susceptible to reductive transformation under conditions that trigger significant mineralogical transformations of synthetic ferrihydrite. No measurable Fe(II)-promoted transformation was observed when the Rifle sediment was exposed to 30 mM Fe(II) for up to 2 weeks. Incubation of the Rifle sediment with 3 mM Fe(II) and 0.2 mM U(VI) for 15 days shows no measurable incorporation of U(VI) into the mineral structure or reduction of U(VI) to U(IV). Results indicate a significantly decreased reactivity of naturally occurring Fe oxyhydroxides as compared to synthetic minerals, likely due to the association of impurities (e.g., Si, organic matter), with implications for the mobility and bioavailability of uranium and other associated species in field environments.

  4. Investigation of efficient {sup 131}I production from natural uranium at Tehran research reactor

    Energy Technology Data Exchange (ETDEWEB)

    Khalafi, H. [Nuclear Research Center, AEOI, No. 54 North Kargar Avenue, P.O. Box 14155/1339, Tehran (Iran, Islamic Republic of)]. E-mail: hossein_khalafi@yahoo.com; Nazari, K. [Jaber-Ibne-Hayan Research laboratories, AEOI, P.O. Box 11365/8486, Tehran (Iran, Islamic Republic of); Ghannadi-Maragheh, M. [Jaber-Ibne-Hayan Research laboratories, AEOI, P.O. Box 11365/8486, Tehran (Iran, Islamic Republic of)

    2005-05-15

    Iodine-131, which has a half-life of 8.05 days, is the one of the most widely used radionuclides in medical diagnosis and treats some diseases of thyroid gland. Optimization of {sup 131}I production in Tehran research reactor (TRR) was studied by two different methods. Primarily, standard nuclear codes such as ORIGEN, WIMS and CITATION were applied and then analytical solutions technique was followed. Calculated results and experimental works in the bench scale indicate that, by irradiation of 100 g natural Uranium (UO{sub 2}) for 100 h at 3.5 x 10{sup 13} (n's/cm{sup 2} s) thermal neutron flux in the TRR, one can produce about 5 Ci of {sup 131}I for medical purposes, on the other hand can produce very useful radionuclides like {sup 99}Mo and {sup 133}Xe in one batch irradiation in the unique production line.

  5. Investigation of efficient 131I production from natural uranium at Tehran research reactor

    International Nuclear Information System (INIS)

    Khalafi, H.; Nazari, K.; Ghannadi-Maragheh, M.

    2005-01-01

    Iodine-131, which has a half-life of 8.05 days, is the one of the most widely used radionuclides in medical diagnosis and treats some diseases of thyroid gland. Optimization of 131 I production in Tehran research reactor (TRR) was studied by two different methods. Primarily, standard nuclear codes such as ORIGEN, WIMS and CITATION were applied and then analytical solutions technique was followed. Calculated results and experimental works in the bench scale indicate that, by irradiation of 100 g natural Uranium (UO 2 ) for 100 h at 3.5 x 10 13 (n's/cm 2 s) thermal neutron flux in the TRR, one can produce about 5 Ci of 131 I for medical purposes, on the other hand can produce very useful radionuclides like 99 Mo and 133 Xe in one batch irradiation in the unique production line

  6. Dietary intake and body content of natural uranium

    International Nuclear Information System (INIS)

    Anon.

    1984-01-01

    The members of the uranium series found in the body that arise primarily from dietary intake are 238 U, 234 U, 226 Ra and 210 Pb. Lead 210, the predominant series radionuclide in the body, decays to the alpha emitter 210 Po, while the others are alpha emitters themselves. While 210 Pb primarily enters the body through diet, inhalation must also be considered, especially in smokers. The primary site of deposition for these nuclides is the skeleton and the dose to bone is the critical factor. In this section, the average background, elevated natural and enhanced dietary intakes of the uranium series radionuclides are discussed. Human skeletal levels and consequent alpha doses are summarized

  7. On the nature of the phase transition in uranium dioxide

    Science.gov (United States)

    Gofryk, K.; Mast, D.; Antonio, D.; Shrestha, K.; Andersson, D.; Stanek, C.; Jaime, M.

    Uranium dioxide (UO2) is by far the most studied actinide material as it is a primary fuel used in light water nuclear reactors. Its thermal and magnetic properties remain, however, a puzzle resulting from strong couplings between magnetism and lattice vibrations. UO2 crystalizes in the face-centered-cubic fluorite structure and is a Mott-Hubbard insulator with well-localized uranium 5 f-electrons. In addition, below 30 K, a long range antiferromagnetic ordering of the electric-quadrupole of the uranium moments is observed, forming complex non-collinear 3-k magnetic structure. This transition is accompanied by Jahn-Teller distortion of oxygen atoms. It is believed that the first order nature of the transition results from the competition between the exchange interaction and the Jahn-Teller distortion. Here we present results of our extensive thermodynamic investigations on well-characterized and oriented single crystals of UO2+x (x = 0, 0.033, 0.04, and 0.11). By focusing on the transition region under applied magnetic field we are able to study the interplay between different competing interactions (structural, magnetic, and electrical), its dynamics, and relationship to the oxygen content. We will discuss implications of these results. Work supported by the Department of Energy, Office of Basic Energy Sciences, Materials Sciences, and Engineering Division.

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

    International Nuclear Information System (INIS)

    Matsuo, Yuhji; Murakami, Tomoko

    2012-01-01

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

  9. Uranium prospecting program: memorandum of request United Nations Assistance Rotatory Fund for Naturals resources in Uranium Prospecting

    International Nuclear Information System (INIS)

    1976-01-01

    The Uruguayan government required assistance to Unit Nations funds with the aim of studies the Natural resources in Uranium prospecting, their antecedent, actual and projected works, equipment and end considerations

  10. 49 CFR 173.426 - Excepted packages for articles containing natural uranium or thorium.

    Science.gov (United States)

    2010-10-01

    ... outer surface of the uranium or thorium is enclosed in an inactive sheath made of metal or other durable... uranium or thorium. 173.426 Section 173.426 Transportation Other Regulations Relating to Transportation....426 Excepted packages for articles containing natural uranium or thorium. A manufactured article in...

  11. Natural radionuclides in the environment and problems of uranium mining

    International Nuclear Information System (INIS)

    Bowie, S.H.U.

    1981-01-01

    The subject is discussed under the headings: introduction (U-238, U-235, Th-232, K-40, and their decay products); distribution of radionuclides; α, β and γ radiation; uranium in rocks; uranium in soil and water; uranium mining (hazards of uranium and radon during mining and in tailings); assessment of risk. (U.K.)

  12. Contribution to the study of the new international philosophy of the radiological safety in the natural uranium chemical treatment

    International Nuclear Information System (INIS)

    Moraes da Silva, T. de

    1990-01-01

    The objective of this work is to adapt the Radiological Safety System in the facilities concerned to the chemical treatment of the uranium concentrated (yellow-cake) until conversion in uranium hexafluoride in the pilot plant of IPEN-CNEN/SP, to the new international philosophy adopted by ICRP and IAEA. The new philosophy changes fully the Radiological Protection concepts of preceding philosophy, changes, also, the concept of the workplace and individual monitoring as well as the classification of the working areas. In this paper we show the monitoring program, in each phase of the natural uranium treatment chemical process in conversion facility for external irradiation, surface contamination and air contamination. The results were analysed according with the new philosophy and used to reclassify the workplace. It was introduced the condition work concept taking account the time spent by the worker in that workplace. (author)

  13. Internal contamination by natural uranium: monitoring by analysis of urine of individuals exposed by occupational inhalation

    International Nuclear Information System (INIS)

    Ramalho, A.T.

    1982-01-01

    Urine samples from men working at Usina Santo Amaro (USAM - State of Sao Paulo), a monazite refinery, were analysed for uranium concentration, using fluorometric analysis and alpha spectrometry. All samples analysed presented uranium concentration below the lower limit of detection. Theoretical values were calculated for uranium concentration in urine samples from workers at the annual limit of intake (ALI) for inhalation of natural uranium, recommended in Publication 30 of the International Commission on Radiological Protection (ICRP, 1979). The two different methods used for analysis of natural uranium concentration in the urine samples were compared: fluorimetry and alpha spectrometry. (author)

  14. Method for the chemical reprocessing of irradiated nuclear fuels, in particular nuclear fuels containing uranium

    International Nuclear Information System (INIS)

    Koch, G.

    1976-01-01

    In the chemical processing of irradiated uranium-containing nuclear fuels which are hydrolyzed with aqueous nitric acid, a suggestion is made to use as quaternary ammonium nitrate trialkyl-methyl ammonium nitrates as extracting agent, in which the sum of C atoms is greater than 16. In the illustrated examples, tricaprylmethylammonium nitrate, trilaurylmethylammonium nitrate and tridecylmethylammonium nitrate are named. (HPH/LH) [de

  15. Shielding Studies for Reducing the associated Radiological Risks Due To Irradiated Low Enriched Uranium Foil

    International Nuclear Information System (INIS)

    Margeanu, C.A.

    2011-01-01

    Present work estimates the radiation dose rates corresponding to irradiated Low Enriched Uranium (20 wt % 235 U) foil as part of shielding studies for radiological risks reduction after irradiation inside TRIGA 14 MW Research Reactor in an investigation on 99 Mo production possibility. Post-Irradiation Examination Laboratory's cell shielding calculations have been performed; radiation source was obtained by using ORIGEN-S code with specific cross-sections libraries. Different post-irradiation cooling times have been considered, gamma dose rates being estimated by using MAVRIC module from Scale 6 programs package, for following exposure situations (relative to Pie cell): i) front side, ii) lateral side and iii) back side. Three different calculations were performed: a) without any protection shield between operator and cell, except for the cell stainless steel wall; b) with a Lead protection shield between operator and cell and c) with a depleted Uranium shield, located inside the cell in between the radiation source and cell window. Radiation dose rates to cell external wall surface and for other eight fixed distances from cell wall were estimated. To obtain a consistent set of solutions, the study was done for various Uranium foil weights and different Lead and depleted Uranium shields thicknesses. Calculations were focused to assure that the dose rate to an operator positioned at 60 cm working distance from the cell will not exceed 0.02 mSv/h, maximum allowed dose rate for professionally exposed personnel according to Romanian regulations.

  16. Stability of uranium silicides during high energy ion irradiation

    International Nuclear Information System (INIS)

    Birtcher, R.C; Wang, L.M.

    1991-11-01

    Changes induced by 1.5 MeV Kr ion irradiation of both U 3 Si and U 3 Si 2 have been followed by in situ transmission electron microscopy. When irradiated at sufficiently low temperatures, both alloys transform from the crystalline to the amorphous state. When irradiated at temperatures above the temperature limit for ion beam amorphization, both compounds disorder with the Martensite twin structure in U 3 Si disappearing from view in TEM. Prolonged irradiation of the disordered crystalline phases results in nucleation of small crystallites within the initially large crystal grains. The new crystallites increase in number during continued irradiation until a fine grain structure is formed. Electron diffraction yields a powder-like diffraction pattern that indicates a random alignment of the small crystallites. During a second irradiation at lower temperatures, the small crystallizes retard amorphization. After 2 dpa at high temperatures, the amorphization dose is increased by over twenty times compared to that of initially unirradiated material

  17. Natural analogue study of uranium deposits in Japan with special reference to the Tono uranium deposit

    International Nuclear Information System (INIS)

    Komuro, Kosei; Sasao, Eiji

    2004-05-01

    In order to verify the safety assessment for geological disposal system of high-level radioactive waste, it is necessary to evaluate properly the stability of the disposal system under natural hydrogeological environment over long period of time (ten to hundred thousands years). For the safety assessment for that in the Japanese Islands, many geological processes inherent in the tectonically active Island-Arc system should be also taken into consideration in addition to those in stable continental environment. However, it is difficult because some processes such as earthquake seem to be accidental and some are periodic or gradual over our life scale. The uranium deposits in Japan are subjected to many geological processes inherent in the tectonically active Island-Arc system. The studies on long-term preservation of uranium deposits in Japan from a natural analogue viewpoint would be expected to provide useful information for the assessment in the Japanese Islands over long period of time. In order to understand the behavior of radionuclides under natural hydrogeological environment in Japanese Islands over long period of time, the uranium deposits in Japan, especially of the Tono uranium deposit was investigated from a natural analogue viewpoint under the course of joint research program by University of Tsukuba and Japan Nuclear Cycle Development Institute. Important conclusions obtained in the present study are summarized as follows: The migration behavior of the radionuclides in the granite area is mainly controlled by the stability of original minerals in oxic condition, being due to poor reducing agents such as organic matter and sulfide minerals. In the case of hydrothermal alteration, yttrialite and fergusonite were decomposed and thorogummite was formed at the altered part, whereas zircon and allanite have not been significantly altered. In the case of weathering, autunite and torbernite were formed, probably due to the high phosphorus weathering

  18. Radiation damage of uranium-thorium oxide, irradiated in water

    International Nuclear Information System (INIS)

    Bloem, P.J.C.; Nagel, W.; Plas, T. van der; Kema, N.V.

    1977-01-01

    A suspension in water of spherical particles of UO 2 -ThO 2 with diameter 5μm has been considered as the working fluid in an aqueous, homogeneous, thermal nuclear reactor. Irradiation experiments have shown that these particles suffer a gradual breakdown when irradiated in water. This behaviour is markedly different from that shown on irradiation in absence of water. As damage was defined the amount of solid dissolved by an etching liquid. Electron microscopic pictures showed that at higher irradiation temperatures in water the actual damage was larger than the etching values indicated. (orig.) [de

  19. The uranium and thorium separation in the chemical reprocessing of the irradiated fuel of thorium and uranium mixed oxides

    International Nuclear Information System (INIS)

    Oliveira, E.F. de.

    1984-09-01

    A bibliographic research has been carried out for reprocessing techniques of irradiated thorium fuel from nuclear reactors. The Thorex/Hoechst process has been specially considered to establish a method for reprocessing thorium-uranium fuel from PWR. After a series of cold tests performed in laboratory it was possible to set the behavior of several parameters affecting the Thorex/Hoechst process. Some comments and suggestions are presented for modifications in the process flosheet conditions. A discussion is carried out for operational conditions such as the aqueous to organic flow ratio the acidity of strip and scrub solutions in the process steps for thorium and uranium recovery. The operation diagrams have been constructed using equilibrium experimental data which correspond to conditions observed in laboratory. (Author) [pt

  20. Estimated natural uranium requirements to the year 2000

    International Nuclear Information System (INIS)

    Bennett, L.L.

    1981-01-01

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

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

    International Nuclear Information System (INIS)

    Zettwoog, Pierre.

    1980-11-01

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

  2. Irradiation testing of high density uranium alloy dispersion fuels

    International Nuclear Information System (INIS)

    Hayes, S.L.; Trybus, C.L.; Meyer, M.K.

    1997-10-01

    Two irradiation test vehicles have been designed, fabricated, and inserted into the Advanced Test Reactor in Idaho. Irradiation of these experiments began in August 1997. These irradiation tests were designed to obtain irradiation performance information on a variety of potential new, high-density dispersion fuels. Each of the two irradiation vehicles contains 32 microplates. Each microplate is aluminum clad, having an aluminum matrix phase and containing one of the following compositions as the fuel phase: U-10Mo, U-8Mo, U-6Mo, U-4Mo, U-9Nb-3Zr, U-6Nb-4Zr, U-5Nb-3Zr, U-6Mo-1Pt, U-6Mo-0.6Ru, U-10Mo-0.05Sn, U 2 Mo, or U 3 Si 2 . These experiments will be discharged at peak fuel burnups of 40% and 80%. Of particular interest is the fission gas retention/swelling characteristics of these new fuel alloys. This paper presents the design of the irradiation vehicles and the irradiation conditions

  3. Irradiation testing of high-density uranium alloy dispersion fuels

    International Nuclear Information System (INIS)

    Hayes, S.L.; Trybus, C.L.; Meyer, M.K.

    1997-01-01

    Two irradiation test vehicles have been designed, fabricated, and inserted into the Advanced Test Reactor in Idaho. Irradiation of these experiments began in August 1997. These irradiation tests were designed to obtain irradiation performance information on a variety of potential new, high-density dispersion fuels. Each of the two irradiation vehicles contains 32 'microplates'. Each microplate is aluminum clad, having an aluminum matrix phase and containing one of the following compositions as the fuel phase: U-10Mo, U-8Mo, U-6Mo, U-4Mo, U-9Nb-3Zr, U-6Nb-4Zr, U-5Nb-3Zr, U-6Mo-1Pt, U-6Mo-0.6Ru, U10Mo-0.05Sn, U2Mo, or U 3 Si 2 . These experiments will be discharged at peak fuel burnups of approximately 40 and 80 at.% U 235 . Of particular interest are the extent of reaction of the fuel and matrix phases and the fission gas retention/swelling characteristics of these new fuel alloys. This paper presents the design of the irradiation vehicles and the irradiation conditions. (author)

  4. 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.

  5. 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

  6. Post irradiation examinations of uranium-plutonium mixed carbide fuels irradiated at low linear power rate

    International Nuclear Information System (INIS)

    Maeda, Atsushi; Sasayama, Tatsuo; Iwai, Takashi; Aizawa, Sakuei; Ohwada, Isao; Aizawa, Masao; Ohmichi, Toshihiko; Handa, Muneo

    1988-11-01

    Two pins containing uranium-plutonium carbide fuels which are different in stoichiometry, i.e. (U,Pu)C 1.0 and (U,Pu)C 1.1 , were constructed into a capsule, ICF-37H, and were irradiated in JRR-2 up to 1.0 at % burnup at the linear heat rate of 420 W/cm. After being cooled for about one year, the irradiated capsule was transferred to the Reactor Fuel Examination Facility where the non-destructive examinations of the fuel pins in the β-γ cells and the destructive ones in two α-γ inert gas atmosphere cells were carried out. The release rates of fission gas were low enough, 0.44 % from (U,Pu)C 1.0 fuel pin and 0.09% from (U,Pu)C 1.1 fuel pin, which is reasonable because of the low central temperature of fuel pellets, about 1000 deg C and is estimated that the release is mainly governed by recoil and knock-out mechanisms. Volume swelling of the fuels was observed to be in the range of 1.3 ∼ 1.6 % for carbide fuels below 1000 deg C. Respective open porosities of (U,Pu)C 1.0 and (U,Pu)C 1.1 fuel were 1.3 % and 0.45 %, being in accordance with the release behavior of fission gas. Metallographic observation of the radial sections of pellets showed the increase of pore size and crystal grain size in the center and middle region of (U,Pu)C 1.0 pellets. The chemical interaction between fuel pellets and claddings in the carbide fuels is the penetration of carbon in the fuels to stainless steel tubes. The depth of corrosion layer in inner sides of cladding tubes ranged 10 ∼ 15 μm in the (U,Pu)C 1.0 fuel and 15 #approx #25 μm in the (U,Pu)C 1.1 fuel, which is correlative with the carbon potential of fuels posibly affecting the amount of carbon penetration. (author)

  7. Determination of natural uranium in urine (233U)

    International Nuclear Information System (INIS)

    Jeanmaire, L.; Jammet, H.

    1959-01-01

    A procedure for the quantitative analysis of uranium in urine is described. The residue obtained by mineralization is dissolved in diluted hydrochloric acid. Uranium is separated by fixation on a permutit 50 column, elution with 0,2 M oxalic acid and electrodeposition on nickel. Uranium is then measured by α counting. It is thus possible to detect less than 1 pico-curie of uranium in the sample. (author) [fr

  8. Irradiation defects in clayey minerals in association with discordance-type uranium deposit; Les Defauts d'Irradiation dans les Mineraux argileux associes aux gisements d'Uranium de type Discordance

    Energy Technology Data Exchange (ETDEWEB)

    Morichon, E.; Beaufort, D. [Universite de Poitiers, Laboratoire HydrASA, CNRS-FRE 3114, 86 - Poitiers (France); Morichon, E.; Allard, Th. [IMPMC, UMR 7590, 75 - Paris (France)

    2009-07-01

    Radioactivity generates defects in minerals and these defects are the witnesses of the presence of radio-elements, and therefore represent an interesting potential for uranium prospecting. Investigations made in the Athabasca basin in Canada reveal irradiation defects in very old clays (kaolinite, illite and sudoite) in the alteration halo of discordance-type uranium deposits. The authors comment the defect concentration variation among the different drillings. These differences show that hexavalent uranium circulated in the whole geological system

  9. Comparative analysis of calculations and experiment for uranium-graphite lattices with natural and slightly-enriched uranium

    International Nuclear Information System (INIS)

    Khrennikov, N.N.; Shchukin, A.V.

    1988-01-01

    Three sets of experiments carried out at different times and in different laboratories on measuring the material parameter for uranium-graphite lattices using natural and slightly enriched uranium are analyzed. Comparison with the calculations by the TRIFOGR and MCU (the Monte Carlo method) codes reveals resonable agreement between the calculation and experiment (of the order of 0.4% in K eff ). 17 refs.; 3 tabs

  10. Developments in natural uranium - graphite reactors; Developpement des reacteurs a graphite et uranium naturel

    Energy Technology Data Exchange (ETDEWEB)

    Bourgeois, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Saitcevsky, B [Electricite de France (EDF), 75 - Paris (France)

    1964-07-01

    The French natural uranium-graphite power-reactor programme has been developing - from EDF 1 to EDF 4 - in the direction of an increase of the unit power of the installations, of the specific and volume powers, and of an improvement in the operational security conditions. The high power of EDF 4 (500 MWe) and the integration of the primary circuit into the reactor vessel, which is itself made of pre-stressed concrete, make it possible to make the most of the annular fuel elements already in use in EDF 1, and to arrive thus at a very satisfactory solution. The use of an internally cooled fuel element (an annular element) has led to a further step forward: it now becomes possible to increase the pressure of the cooling gas without danger of causing creep in the uranium tube. The use of a pre-stressed concrete vessel makes this pressure increase possible, and the integration of the primary circuit avoids the risk of a rapid depressurization which would be in this case a major danger. This report deals with the main problems presented by this new type of nuclear power station, and gives the main lines of research and studies now being carried out in France. - Neutronic and thermal research has made it possible to consider using large size fuel elements (internal diameter = 77 mm, external diameter 95 mm) while still using natural uranium. - The problems connected with the production of these elements and with their in pile behaviour are the subject of a large programme, both out of pile and in power reactors (EDF 2) and test reactors (Pegase). - The increase in the size of the element leads to a large lattice pitch (35 to 40 cm). This makes it possible to consider having one charging aperture per channel or for a small number of channels, whether the charge machine be inside or outside the pressure vessel. In conclusion are given the main characteristics of a project for a 500 MWe power station using such a fuel element. In particular this project is compared to EDF 4

  11. Developments in natural uranium - graphite reactors; Developpement des reacteurs a graphite et uranium naturel

    Energy Technology Data Exchange (ETDEWEB)

    Bourgeois, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Saitcevsky, B. [Electricite de France (EDF), 75 - Paris (France)

    1964-07-01

    The French natural uranium-graphite power-reactor programme has been developing - from EDF 1 to EDF 4 - in the direction of an increase of the unit power of the installations, of the specific and volume powers, and of an improvement in the operational security conditions. The high power of EDF 4 (500 MWe) and the integration of the primary circuit into the reactor vessel, which is itself made of pre-stressed concrete, make it possible to make the most of the annular fuel elements already in use in EDF 1, and to arrive thus at a very satisfactory solution. The use of an internally cooled fuel element (an annular element) has led to a further step forward: it now becomes possible to increase the pressure of the cooling gas without danger of causing creep in the uranium tube. The use of a pre-stressed concrete vessel makes this pressure increase possible, and the integration of the primary circuit avoids the risk of a rapid depressurization which would be in this case a major danger. This report deals with the main problems presented by this new type of nuclear power station, and gives the main lines of research and studies now being carried out in France. - Neutronic and thermal research has made it possible to consider using large size fuel elements (internal diameter = 77 mm, external diameter 95 mm) while still using natural uranium. - The problems connected with the production of these elements and with their in pile behaviour are the subject of a large programme, both out of pile and in power reactors (EDF 2) and test reactors (Pegase). - The increase in the size of the element leads to a large lattice pitch (35 to 40 cm). This makes it possible to consider having one charging aperture per channel or for a small number of channels, whether the charge machine be inside or outside the pressure vessel. In conclusion are given the main characteristics of a project for a 500 MWe power station using such a fuel element. In particular this project is compared to EDF 4

  12. Nondestructive analysis of the natural uranium mass through the measurement of delayed neutrons using the technique of pulsed neutron source

    International Nuclear Information System (INIS)

    Coelho, Paulo Rogerio Pinto

    1979-01-01

    This work presents results of non destructive mass analysis of natural uranium by the pulsed source technique. Fissioning is produced by irradiating the test sample with pulses of 14 MeV neutrons and the uranium mass is calculated on a relative scale from the measured emission of delayed neutrons. Individual measurements were normalised against the integral counts of a scintillation detector measuring the 14 MeV neutron intensity. Delayed neutrons were measured using a specially constructed slab detector operated in anti synchronism with the fast pulsed source. The 14 MeV neutrons were produced via the T(d,n) 4 He reaction using a 400 kV Van de Graaff accelerated operated at 200 kV in the pulsed source mode. Three types of sample were analysed, namely: discs of metallic uranium, pellets of sintered uranium oxide and plates of uranium aluminium alloy sandwiched between aluminium. These plates simulated those of Material Testing Reactor fuel elements. Results of measurements were reproducible to within an overall error in the range 1.6 to 3.9%; the specific error depending on the shape, size and mass of the sample. (author)

  13. On the changing petroleum generation properties of Alum Shale over geological time caused by uranium irradiation

    Science.gov (United States)

    Yang, Shengyu; Schulz, Hans-Martin; Horsfield, Brian; Schovsbo, Niels H.; Noah, Mareike; Panova, Elena; Rothe, Heike; Hahne, Knut

    2018-05-01

    An interdisciplinary study was carried out to unravel organic-inorganic interactions caused by the radiogenic decay of uranium in the immature organic-rich Alum Shale (Middle Cambrian-Lower Ordovician). Based on pyrolysis experiments, uranium content is positively correlated with the gas-oil ratios and the aromaticities of both the free hydrocarbons residing in the rock and the pyrolysis products from its kerogen, indicating that irradiation has had a strong influence on organic matter composition overall and hence on petroleum potential. The Fourier Transform Ion Cyclotron Resonance mass spectrometry data reveal that macro-molecules in the uranium-rich Alum Shale samples are less alkylated than less irradiated counterparts, providing further evidence for structural alteration by α-particle bombardment. In addition, oxygen containing-compounds are enriched in the uranium-rich samples but are not easily degradable into low-molecular-weight products due to irradiation-induced crosslinking. Irradiation has induced changes in organic matter composition throughout the shale's entire ca. 500 Ma history, irrespective of thermal history. This factor has to be taken into account when reconstructing petroleum generation history. The Alum Shale's kerogen underwent catagenesis in the main petroleum kitchen area 420-340 Ma bp. Our calculations suggest the kerogen was much more aliphatic and oil-prone after deposition than that after extensive exposure to radiation. In addition, the gas sorption capacity of the organic matter in the Alum Shale can be assumed to have been less developed during Palaeozoic times, in contrast to results gained by sorption experiments performed at the present day, for the same reason. The kerogen reconstruction method developed here precludes overestimations of gas generation and gas retention in the Alum Shale by taking irradiation exposure into account and can thus significantly mitigate charge risk when applied in the explorations for both

  14. Post-irradiation examinations of uranium-plutonium mixed nitride fuel irradiated in JMTR (89F-3A capsule)

    International Nuclear Information System (INIS)

    Iwai, Takashi; Nakajima, Kunihisa; Kikuchi, Hironobu; Arai, Yasuo; Kimura, Yasuhiko; Nagashima, Hisao; Sekita, Noriaki

    2000-03-01

    Two helium-bonded fuel pins filled with uranium-plutonium mixed nitride pellets were encapsulated in 89F-3A and irradiated in JMTR up to 5.5% FIMA at a maximum linear power of 73 kW/m. The capsule cooled for ∼5 months was transported to Reactor Fuel Examination Facility and subjected to non-destructive and destructive post irradiation examinations. Any failure was not observed in the irradiated fuel pins. Very low fission gas release rate of about 2 ∼ 3% was observed, while the diametric increase of fuel pin was limited to ∼0.4% at the position of maximum reading. The inner surface of cladding tube did not show any signs of chemical interaction with fuel pellet. (author)

  15. Irradiation behavior of uranium oxide - Aluminum dispersion fuel

    International Nuclear Information System (INIS)

    Hofman, Gerard L.; Rest, Jeffrey; Snelgrove, James L.

    1996-01-01

    An oxide version of the DART code has been generated in order to assess the irradiation behavior of UO 2 -Al dispersion fuel. The aluminum-fuel interaction models were developed based on U 3 O 8 -Al irradiation data. Deformation of the fuel element occurs due to fuel particle swelling driven by both solid and gaseous fission products and as a consequence of the interaction between the fuel particles and the aluminum matrix. The calculations show that, with the assumption that the correlations derived from U 3 O 8 are valid for UO 2 , the LEU UO 2 -Al with a 42% fuel volume loading (4 g U/cm 3 ) irradiated at fuel temperatures greater than 413 K should undergo breakaway swelling at core burnups greater than about 1.12 x 10 27 fissions m -3 (∼63% 235 U burnup). (author)

  16. Irradiation behavior of uranium oxide-aluminum dispersion fuel

    International Nuclear Information System (INIS)

    Hofman, G.L.; Rest, J.; Snelgrove, J.L.

    1996-01-01

    An oxide version of the DART code has been generated in order to assess the irradiation behavior of UO 2 -Al dispersion fuel. The aluminum-fuel interaction models were developed based on U 3 O 8 -Al irradiation data. Deformation of the fuel element occurs due to fuel particle swelling driven by both solid and gaseous fission products, as well as a consequence of the interaction between the fuel particles and the aluminum matrix. The calculations show, that with the assumption that the correlations derived from U 3 O 8 are valid for UO 2 , the LEU UO 2 -Al with a 42% fuel volume loading (4 gm/cc) irradiated at fuel temperatures greater than 413 K should undergo breakaway swelling at core burnups greater than about 1.12 x 10 27 fissions m -3 (∼ 63% 235 U burnup)

  17. Irradiation effects of the zirconium oxidation and the uranium diffusion in zirconia; Effets d'irradiation sur l'oxydation du zirconium et la diffusion de l'uranium dans la zircone

    Energy Technology Data Exchange (ETDEWEB)

    Bererd, N

    2003-07-01

    The context of this study is the direct storage of spent fuel assemblies after operation in reactor. In order to obtain data on the capacities of the can as the uranium diffusion barrier, a fundamental study has been carried out for modelling the internal cladding surface under and without irradiation. The behaviour of zirconium in reactor conditions has at first been studied. A thin uranium target enriched with fissile isotope has been put on a zirconium sample, the set being irradiated by a thermal neutrons flux leading to the fission of the deposited uranium. The energetic history of the formed fission products has revealed two steps: 1)the zirconium oxidation and 2)the diffusion of uranium in the zirconia formed at 480 degrees C. A diffusion coefficient under irradiation has been measured. Its value is 10{sup -15} cm{sup 2}.s{sup -1}. In order to be able to reveal clearly the effect of the irradiation by the fission products on the zirconium oxidation, measurements of thermal oxidation and under {sup 129}Xe irradiation have been carried out. They have shown that the oxidation is strongly accelerated by the irradiation and that the temperature is negligible until 480 degrees C. On the other hand, the thermal diffusion of the uranium in zirconium and in zirconia has been studied by coupling ion implantation and Rutherford backscattering spectroscopy. This study shows that the uranium diffuses in zirconium and is trapped in zirconia in a UO{sub 3} shape. (O.M.)

  18. Characteristics of the natural uranium ingots developed in IPEN - CNEN/SP

    International Nuclear Information System (INIS)

    Soares, M.C.B.; Koshimizu, S.

    1990-01-01

    The natural uranium consists of two primary isotopes, the U sup(235) (0,7%) and the U sup(238) (99,3%). The isotopic separation carried out in order to obtain enriched uranium, generates a by-product called depleted uranium, which can be applied for industrial uses. The most singular property, from engineering standpoint, is its high density. When the density is the only important factor, the uranium has great advantage over other heavy metals related to economic and technical considerations. Among some applications of uranium are aircraft and missile counterweights, kinetics energy penetrators, radiation shielding, gyro rotors and oil-well sinker bars. The uranium ingot fabrication is done by direct reduction of UF, with magnesium, without remelting. The microstructure of as-cast uranium is, as in the other as-cast, formed by coarse and. (author)

  19. Contamination with uranium from natural and anthropological sources

    International Nuclear Information System (INIS)

    Todorov, Peter Todorov; Ilieva, Elica Nikolova

    2005-01-01

    Our world is radioactive and always was since it was created. Radioactive elements are often called radioactive isotopes or radionuclides. Radionuclides are found in the environment as naturally occurring elements and as products or byproducts of nuclear technologies. One of the most common radionuclides is Uranium (U). U with atomic number of 92 is the heaviest known natural element. All U isotopes are radioactive. So it is very important their quantity to be under control. Natural U is used in the generation of nuclear fuel. U - 235 is one of two fissile materials used for the production of nuclear weapons and in some nuclear reactors as a source of energy. Because of its use in the fission process U is found in large quantities in stored nuclear waste. Other important source of U to the environment was the nuclear weapon tests, especially during the second half of 20th century. Artificial radionuclides may also be released into the environment from non - nuclear cycle activities in industry and research and from usage in diagnostic and therapeutic medicine. Erosion of agricultural soils may input the 238 U decay radionuclides into drinking water supplies in areas with heavy fertilizer usage. The most common routes of U contamination are through handling, ingesting and inhaling. Inhaling and ingesting increase the risk of lung and bone cancer. U is also chemically toxic at high concentrations. U may also affect reproductive organs and the foetus, and may increase the risk of leukemia and soft tissue cancer. (authors)

  20. Irradiated uranium reprocessing, Final report - I-IV, Part I; Prerada ozracenog urana, Zavrsni izvestaj- I-VI, I Deo

    Energy Technology Data Exchange (ETDEWEB)

    Gal, I [Institute of Nuclear Sciences Boris Kidric, Laboratorija za visoku aktivnost, Vinca, Beograd (Serbia and Montenegro)

    1961-12-15

    This volume of the final report describes the construction and functioning of the cell for dissolving the irradiated uranium. Annexes of this report describe the parts of the cell as follows: description of the metal frame, grid and stainless steel plate; container for irradiated uranium; small opening of the cell; vessel for dissolving; device for opening the cover; device for sampling of the radioactive solution, inner and outer parts; pneumatic taps.

  1. Chlorine diffusion in uranium dioxide under heavy ion irradiation

    International Nuclear Information System (INIS)

    Pipon, Y.; Bererd, N.; Moncoffre, N.; Peaucelle, C.; Toulhoat, N.; Jaffrezic, H.; Raimbault, L.; Sainsot, P.; Carlot, G.

    2007-01-01

    The radiation enhanced diffusion of chlorine in UO 2 during heavy ion irradiation is studied. In order to simulate the behaviour of 36 Cl, present as an impurity in UO 2 , 37 Cl has been implanted into the samples (projected range 200 nm). The samples were then irradiated with 63.5 MeV 127 I at two fluxes and two temperatures and the chlorine distribution was analyzed by SIMS. The results show that, during irradiation, the diffusion of the implanted chlorine is enhanced and slightly athermal with respect to pure thermal diffusion. A chlorine gain of 10% accumulating near the surface has been observed at 510 K. This corresponds to the displacement of pristine chlorine from a region of maximum defect concentration. This behaviour and the mean value of the apparent diffusion coefficient found for the implanted chlorine, around 2.5 x 10 -14 cm 2 s -1 , reflect the high mobility of chlorine in UO 2 during irradiation with fission products

  2. Chlorine diffusion in uranium dioxide under heavy ion irradiation

    Science.gov (United States)

    Pipon, Y.; Bérerd, N.; Moncoffre, N.; Peaucelle, C.; Toulhoat, N.; Jaffrézic, H.; Raimbault, L.; Sainsot, P.; Carlot, G.

    2007-04-01

    The radiation enhanced diffusion of chlorine in UO2 during heavy ion irradiation is studied. In order to simulate the behaviour of 36Cl, present as an impurity in UO2, 37Cl has been implanted into the samples (projected range 200 nm). The samples were then irradiated with 63.5 MeV 127I at two fluxes and two temperatures and the chlorine distribution was analyzed by SIMS. The results show that, during irradiation, the diffusion of the implanted chlorine is enhanced and slightly athermal with respect to pure thermal diffusion. A chlorine gain of 10% accumulating near the surface has been observed at 510 K. This corresponds to the displacement of pristine chlorine from a region of maximum defect concentration. This behaviour and the mean value of the apparent diffusion coefficient found for the implanted chlorine, around 2.5 × 10-14 cm2 s-1, reflect the high mobility of chlorine in UO2 during irradiation with fission products.

  3. Burn-up determination of irradiated uranium oxide by means of direct gama spectrometry and by radiochemical method

    International Nuclear Information System (INIS)

    Cunha, I.I.L.; Nastasi, M.J.C.; Lima, F.W.

    1981-09-01

    The burn-up of thermal neutrons irradiated U 3 O 8 (natural uranium) samples has been determined by using both direct gamma spectrometry and radiochemical methods and the results obtained were compared. The fission products 144 Ce, 103 Ru, 106 Ru, 137 Cs and 95 Zr were chosen as burn-up monitors. In order to isolate the radioisotopes chosen as monitors, a radiochemical separation procedure has been established, in which the solvent extraction technique was used to separate cerium, cesium and ruthenium one from the other and all of them from uranium. The separation between zirconium and niobium and of both elements from the other radioisotopes and uranium was accomplished by means of adsorption on a silica-gel column, followed by selective elution of zirconium and of niobium. When use was made of the direct gamma-ray spectrometry method, the radioactivity of each nuclide of interest was measured in presence of all others. For this purpose use was made of gamma-ray spectrometry and of a Ge-Li detector. Comparison of burn-up values obtained by both methods was made by means of Student's 't' test, and this showed that results obtained in each case are statistically equal. (Author) [pt

  4. Comparison of the Economic Aspects of the Treatment and Storage of Fission Products from Installations Processing Irradiated Natural Uranium; Aspects Economiques Compares du Traitement et du Stockage des Produits de Fission Issus des Usines de Traitement de l'Uranium Naturel Irradie; Sravnitel'nye ehkonomicheskie aspekty obrabotki i khraneniya produktov deleniya, poluchaemykh na zavodakh po pererabotke obluchennogo prirodnogo urana; Aspectos Economicos Comparados del Tratamiento y del Almacenamiento de los Productos de Fision que Salen de las Plantas de Tratamiento de Uranio Natural Irradiado

    Energy Technology Data Exchange (ETDEWEB)

    Thiriet, L.; Lesur, P.; Giraud, R. [Commissariat a l' Energie Atomique, Paris (France); Wanlin, J. [Societe Saint-Gobain Techniques Nouvelles, Paris (France)

    1966-02-15

    The paper summarizes the main policies adopted for the management of fission product effluents and briefly describes the essential technical features of the stainless steel storage installations (in acid medium) used in France, giving a breakdown of the costs involved. The dependence of these costs on the activity of the solutions stored and on their heat release is shown. The second part of the paper discusses the cost of storage in terms of feasible tank size. The optimum size for such tanks and the rate at which they are placed in service are determined in relation to the characteristics of the fission products to be stored and to the respective capacities of the installations for processing irradiated natural uranium. It is shown that although storage costs depend on the assumptions made regarding the useful life of installations, rates of interest and operating costs, optimum policy decisions (as to size and rate of entry into service) are independent of these assumptions, being determined solely by the variation in the cost of tanks, according to size. These are the factors which enter into the optimized cost of storing these effluents indefinitely. In the third part, this method of indefinite storage is compared with other possibilities of fission product management, e.g. vitrification and separation of Cs and Sr. The paper discusses the economics of the various methods and summarizes some possible long-term solutions. (author) [French] Apres avoir rappele les principales politiques de gestion le plus souvent envisagees pour les produits de fission, le memoire decrit sommairement les caracteristiques techniques essentielles des installations de stockage en acier inoxydable (en milieu acide) utilisees en France et la structure des couts de ces installations. U montre la sensibilite de ces couts a l'activite des solutions stockees et a leur degagement de chaleur. Dans une deuxieme partie, les auteurs examinent leur cout de stockage, selon la taille des

  5. 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.)

  6. Paleo-channel deposition of natural uranium at a US Air Force landfill

    International Nuclear Information System (INIS)

    Young, Carl; Weismann, Joseph; Caputo, Daniel

    2007-01-01

    Available in abstract form only. Full text of publication follows: The US Air Force sought to identify the source of radionuclides that were detected in groundwater surrounding a closed solid waste landfill at the former Lowry Air Force Base in Denver, Colorado, USA. Gross alpha, gross beta, and uranium levels in groundwater were thought to exceed US drinking water standards and down-gradient concentrations exceeded up-gradient concentrations. Our study has concluded that the elevated radionuclide concentrations are due to naturally-occurring uranium in the regional watershed and that the uranium is being released from paleo-channel sediments beneath the site. Groundwater samples were collected from monitor wells, surface water and sediments over four consecutive quarters. A list of 23 radionuclides was developed for analysis based on historical landfill records. Concentrations of major ions and metals and standard geochemical parameters were analyzed. The only radionuclide found to be above regulatory standards was uranium. A search of regional records shows that uranium is abundant in the upstream drainage basin. Analysis of uranium isotopic ratios shows that the uranium has not been processed for enrichment nor is it depleted uranium. There is however slight enrichment in the U-234:U- 238 activity ratio, which is consistent with uranium that has undergone aqueous transport. Comparison of up-gradient versus down-gradient uranium concentrations in groundwater confirms that higher uranium concentrations are found in the down-gradient wells. The US drinking water standard of 30 μg/L for uranium was exceeded in some of the up-gradient wells and in most of the down-gradient wells. Several lines of evidence indicate that natural uranium occurring in streams has been preferentially deposited in paleo-channel sediments beneath the site, and that the paleo-channel deposits are causing the increased uranium concentrations in down-gradient groundwater compared to up

  7. Recent irradiation tests of uranium-plutonium-zirconium metal fuel elements

    International Nuclear Information System (INIS)

    Pahl, R.G.; Lahm, C.E.; Villarreal, R.; Hofman, G.L.; Beck, W.N.

    1986-09-01

    Uranium-Plutonium-Zirconium metal fuel irradiation tests to support the ANL Integral Fast Reactor concept are discussed. Satisfactory performance has been demonstrated to 2.9 at.% peak burnup in three alloys having 0, 8, and 19 wt % plutonium. Fuel swelling measurements at low burnup in alloys to 26 wt % plutonium show that fuel deformation is primarily radial in direction. Increasing the plutonium content in the fuel diminishes the rate of fuel-cladding gap closure and axial fuel column growth. Chemical redistribution occurs by 2.1 at.% peak burnup and generally involves the inward migration of zirconium and outward migration of uranium. Fission gas release to the plenum ranges from 46% to 56% in the alloys irradiated to 2.9 at.% peak burnup. No evidence of deleterious fuel-cladding chemical or mechanical interaction was observed

  8. Graphite Isotope Ratio Method Development Report: Irradiation Test Demonstration of Uranium as a Low Fluence Indicator

    International Nuclear Information System (INIS)

    Reid, B.D.; Gerlach, D.C.; Love, E.F.; McNeece, J.P.; Livingston, J.V.; Greenwood, L.R.; Petersen, S.L.; Morgan, W.C.

    1999-01-01

    This report describes an irradiation test designed to investigate the suitability of uranium as a graphite isotope ratio method (GIRM) low fluence indicator. GIRM is a demonstrated concept that gives a graphite-moderated reactor's lifetime production based on measuring changes in the isotopic ratio of elements known to exist in trace quantities within reactor-grade graphite. Appendix I of this report provides a tutorial on the GIRM concept

  9. Progress in irradiation performance of experimental uranium - Molybdenum dispersion fuel

    International Nuclear Information System (INIS)

    Hofman, Gerard L.; Meyer, Mitchell K.

    2002-01-01

    High-density dispersion fuel experiment, RERTR-4, was removed from the Advanced Test Reactor (ATR) after reaching a peak U-235 burnup of ∼80% and is presently undergoing postirradiation examination at the ANL alpha-gamma hot cells. This test consists of 32 mini fuel plates of which 27 were fabricated with nominally 6 and 8 g cm -3 atomized and machined uranium alloy powders containing 7 wt% and 10 wt% molybdenum. In addition, two miniplates containing solid U-10 wt% Mo foils and three containing 6 g cm -3 U 3 Si 2 are part of the test. The results of the postirradiation examination and analysis of RERTR-4 in conjunction with data from previous tests performed to lower burnup will be presented. (author)

  10. Radioactive decay properties of CANDU fuel. Volume 1: the natural uranium fuel cycle

    International Nuclear Information System (INIS)

    Clegg, L.J.; Coady, J.R.

    1977-01-01

    The computer code CANIGEN was used to obtain the mass, activity, decay heat and toxicity of CANDU fuel and its component isotopes. Data are also presented on gamma spectra and neutron emissions. Part 1 presents these data for unirradiated fuel, uranium ore and uranium mill tailings. In Part 2 they have been computed for fuel irradiated to levels of burnup ranging from 140 GJ/kg U to 1150 GJ/kg U. (author)

  11. 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)

  12. Thermophysical properties of the irradiated uranium-zirconium fuel

    International Nuclear Information System (INIS)

    Gajduchenko, A.B.

    2008-01-01

    The dependence of the thermophysical properties of metallic nuclear fuel, i.e. Zr alloy 40U, in a wide temperature range as a function of accumulated fission products amount is presented. Both non-irradiated and irradiated test pieces with different degrees of accumulation of fission products, i.e. 0.4, 0.6, and 0.9 g/cm 3 , are investigated. The specific heat is measured in the range of 50-1000 deg C, the thermal diffusivity is measured in the range 300-1000 deg C, and the variation of the dimensions and density of the samples on heating is also investigated. The thermal conductivity in the range of 50-1000 deg C is calculated on the basis of the experimental data [ru

  13. Cracking and bulk movement in irradiated uranium oxide fuel elements

    International Nuclear Information System (INIS)

    Bain, A.S.

    1963-09-01

    UO 2 pellets were fabricated with simulated circumferential or diametral cracks, and with voids formed by drilling axial or radial holes. Under irradiation the cracks healed in a region extending out slightly beyond the area of discernible grain growth. Cracks in the cooler outer annulus formed early and remained during the irradiation. Similarly voids in the outer annulus were unchanged, whereas those in the grain-growth region closed. Tungsten wire markers stayed in their original positions, demonstrating that the surrounding columnar grains in the UO 2 had not formed during the solidification of a melt. Decreases in diameter of 1 mm thick Zircaloy-2 sheathing assembled with large fuel/sheath diametral clearances were due to multi-axial stresses arising from axial elongation and the lack of diametral restraint. (author)

  14. Cracking and bulk movement in irradiated uranium oxide fuel elements

    Energy Technology Data Exchange (ETDEWEB)

    Bain, A S

    1963-09-15

    UO{sub 2} pellets were fabricated with simulated circumferential or diametral cracks, and with voids formed by drilling axial or radial holes. Under irradiation the cracks healed in a region extending out slightly beyond the area of discernible grain growth. Cracks in the cooler outer annulus formed early and remained during the irradiation. Similarly voids in the outer annulus were unchanged, whereas those in the grain-growth region closed. Tungsten wire markers stayed in their original positions, demonstrating that the surrounding columnar grains in the UO{sub 2} had not formed during the solidification of a melt. Decreases in diameter of 1 mm thick Zircaloy-2 sheathing assembled with large fuel/sheath diametral clearances were due to multi-axial stresses arising from axial elongation and the lack of diametral restraint. (author)

  15. Preparation and Purification of natural uranium metal by Iodine method

    International Nuclear Information System (INIS)

    Taies, J.A.

    2008-01-01

    In this work ,glass-metal apparatus was designed and manufactured which used for preparing a high purity uranium.The reaction is simply take place between iodine vapour and uranium metal at 500C in closed system to form uranium tetra iodide which is decomposed on hot wire at high temperature around 1100C.Also another apparatus was made from Glass and used for preparing a high purity of UI 4 more than 99.9%purity

  16. Temperature Dependence of Uranium and Vanadium Adsorption on Amidoxime-Based Adsorbents in Natural Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, Li-Jung [Marine Sciences Laboratory, Pacific Northwest National Laboratory, Sequim WA 98382 USA; Gill, Gary A. [Marine Sciences Laboratory, Pacific Northwest National Laboratory, Sequim WA 98382 USA; Tsouris, Costas [Oak Ridge National Laboratory, Oak Ridge TN 37831 USA; Rao, Linfeng [Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley CA 94720 USA; Pan, Horng-Bin [Department of Chemistry, University of Idaho, Moscow ID 83844 USA; Wai, Chien M. [Department of Chemistry, University of Idaho, Moscow ID 83844 USA; Janke, Christopher J. [Oak Ridge National Laboratory, Oak Ridge TN 37831 USA; Strivens, Jonathan E. [Marine Sciences Laboratory, Pacific Northwest National Laboratory, Sequim WA 98382 USA; Wood, Jordana R. [Marine Sciences Laboratory, Pacific Northwest National Laboratory, Sequim WA 98382 USA; Schlafer, Nicholas [Marine Sciences Laboratory, Pacific Northwest National Laboratory, Sequim WA 98382 USA; D' Alessandro, Evan K. [Rosensteil School of Marine and Atmospheric Chemistry, University of Miami, Miami FL 33149 USA

    2018-01-16

    The apparent enthalpy and entropy of the complexation of uranium (VI) and vanadium (V) with amidoxime ligands grafted onto polyethylene fiber was determined using time series measurements of adsorption capacities in natural seawater at three different temperatures. The complexation of uranium was highly endothermic, while the complexation of vanadium showed minimal temperature sensitivity. Amidoxime-based polymeric adsorbents exhibit significantly increased uranium adsorption capacities and selectivity in warmer waters.

  17. Natural β-carotene and whole body irradiation in rats

    International Nuclear Information System (INIS)

    Ben-Amotz, A.; Rachmilevich, B.; Greenberg, S.; Sela, M.; Weshler, Z.

    1996-01-01

    β-Carotene and other carotenoids are reported to be potent free radical quenchers, singlet oxygen scavengers, and lipid antioxidants. Whole-body irradiation is known to cause an immunosuppression effect in mammals through the possible initiation and production of reactive oxygen species. We decided to test the possible antioxidative effect against whole-body irradiation of a natural β-carotene, composed of equal amounts of the all-trans and 9-cis isomers, obtained from the unicellular alga Dunaliella bardawil. Rats were fed on ground commercial food enriched with natural β-carotene (50 mg/kg diet). On completion of 1 week with β-carotene, the rats were exposed to a single dose of 4 Gy whole-body irradiation, after which their livers and blood were removed for β-carotene and retinol analysis in comparison with control livers of animals irradiated or not, or supplemented with β-carotene after irradiation. A normal increase in body weight with no ill effects was noted in the groups of rats whose diet was supplemented by β-carotene before and after irradiation, compared with the reduction in the specific growth rate in the group of rats irradiated without β-carotene. Liver β-carotene and retinol decreased significantly after irradiation compared with the rats which were not irradiated. This decrease was not shown in rats fed β-carotene prior to irradiation, and the effect of irradiation was partially cured by supplementation with β-carotene after irradiation. High-pressure liquid chromatography (HPLC) analysis of the irradiated animals showed a selective decline in 9-cis β-carotene and in retinol over all-trans β-carotene and retinyl esters. These results suggest that 9-cis β-carotene and retinol protect in vivo against the cellular damage by free radicals induced after whole-body irradiation. (orig.). With 1 fig., 2 tabs

  18. Study of Irradiation Effect onto Uranium silicide Fuel

    International Nuclear Information System (INIS)

    Suparjo

    1998-01-01

    The irradiation effect onto the U 3 Si-Al and U 3 Si 2 -Al dispersion type of fuel element has been studied. The fuel material performs swelling during irradiation due to boehmite (Al 2 O 3 (H 2 O)) formation in which might occurs inside the meat and on the cladding surface, the interaction between the fuel and aluminium matrix that produce U(Al,Si) 3 phase, and the formation of fission gas bubble inside the fuel. At a constant fission density, the U 3 Si-Al fuel swelling is higher than that of U 3 Si 2 -Al fuel. The swellings of both fuels increase with the increasing of fission density. The difference of swelling behavior was caused by formation of large bubble gases generated from fission product of U 3 Si fuel and distributed non-uniformly over all of fuel zone. On the other hand, the U 3 Si 2 fission produced small bubble gases, and those were uniformly distributed. The growth rate of fission gas bubble in the U 3 Si fuel has shown high diffusivity, transformation into amorph material and thus decrease its mechanical strength

  19. Determination of natural uranium, thorium and radium isotopes in water and soil samples by alpha spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Le Cong; Tao, Chau Van; Thong, Luong Van; Linh, Duong Mong [University of Science Ho Chi Minh City (Viet Nam). Faculty of Physics and Engineering Physics; Dong, Nguyen Van [University of Science Ho Chi Minh City (Viet Nam). Faculty of Chemistry

    2011-08-15

    In this study, a simple procedure for the determination of natural uranium, thorium and radium isotopes in water and soil samples by alpha spectroscopy is described. This procedure allows a sequential extraction polonium, uranium, thorium and radium radionuclides from the same sample in two to three days. It was tested and validated with the analysis of certified reference materials from the IAEA. (orig.)

  20. 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)

  1. Some physical properties of irradiated and non-irradiated oxide glasses containing uranium

    International Nuclear Information System (INIS)

    Simon, V.; Ardelean, I.; Simon, S.; Cozar, O.; Milea, I.; Lupsa, I.; Mih, V.

    1995-01-01

    The x U O 3 (1-x) [2 P 2 O 5 · Na 2 O] non-irradiated and gamma irradiated glasses (0 3+ , U 4+ and U 5+ ions. The gamma irradiation induces paramagnetic defects around the glass network forming sites occupied by phosphorous atoms. The non-irradiated samples are weak paramagnetic up to x = 0.1. For higher U O 3 concentration (0.1 < x ≤ 0.2) the magnetic measurements indicated a larger number of paramagnetic ions which are magnetically isolated and exhibit a Curie type behaviour. (author) 5 figs., 14 refs

  2. Uranium

    International Nuclear Information System (INIS)

    Anon.

    1984-01-01

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

  3. Uranium

    International Nuclear Information System (INIS)

    Mackay, G.A.

    1978-01-01

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

  4. Uranium

    International Nuclear Information System (INIS)

    1982-01-01

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

  5. Uranium

    International Nuclear Information System (INIS)

    Stewart, E.D.J.

    1974-01-01

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

  6. Uranium

    International Nuclear Information System (INIS)

    Toens, P.D.

    1981-03-01

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

  7. Micro-hardness of non-irradiated uranium dioxide

    International Nuclear Information System (INIS)

    Kim, Sung-Sik; Takagi, Osamu; Obata, Naomi; Kirihara, Tomoo.

    1983-01-01

    In order to obtain the optimum conditions for micro-hardness measurements of sintered UO 2 , two kinds of hardness tests (Vickers and Knoop) were examined with non-irradiated UO 2 of 2.5 and 5 μm in grain size. The hardness values were obtained as a function of the applied load in the load range of 25 -- 1,000 g. In the Vickers test, cracks were generated around the periphery of an indentation even at lower load of 50 g, which means the Vickers hardness is not suitable for UO 2 specimens. In the Knoop test, three stages of load dependence were observed for sintered pellet as well as for a single crystal by Bates. Load dependence of Knoop hardness and crack formation were discussed. In the range of applied load around 70 -- 100 g there were plateau region where hardness values were nearly unchanged and did not contain any cracks in the indentation. The plateau region represents a hardness of a specimen. From a comparison between the hardness values of 2.5 μm and those of 5 μm UO 2 , it was approved that the degree of sintering controls the hardness in the plateau region. (author)

  8. World nuclear fuel supply and demand prospects until 2030. Analysis of demand change factor of natural uranium and uranium separation work and its influence

    International Nuclear Information System (INIS)

    Murakami, Tomoko

    2007-01-01

    World nuclear power generation continues to spread gently until 2030 from the viewpoint of increase of the electricity demand around Asia, stable energy supply and anti-global warming measure, and the natural uranium demand is predicted to be increased from about 67 ktU in 2004 to 80-100 ktU in 2030. Steps of conversion/separation/reconversion/molding processing of the natural uranium are necessary for nuclear fuel, and the separation work of those is important because it needs high technology. There is a relation of the trade-off through the tale density (0.3% as a standard) between natural uranium and separation work demand. Therefore an analysis was performed of the influence on natural uranium and separation work demand by the change of the tale density and the influence on natural uranium supply and demand prospects by the recovery uranium use. In conclusion it was very likely that the supply and demand of separation work was tight at 0.2%-0.1% as for the cost of most suitable tale density which would appear earlier than natural uranium one and that the recovery uranium could become the backup of the natural uranium. (T. Tanaka)

  9. Elimination of natural uranium and 226Ra from contaminated waters by rhizofiltration using Helianthus annuus L

    International Nuclear Information System (INIS)

    Vera Tome, F.; Blanco Rodriguez, P.; Lozano, J.C.

    2008-01-01

    The elimination of natural uranium and 226 Ra from contaminated waters by rhizofiltration was tested using Helianthus annuus L. (sunflower) seedlings growing in a hydroponic medium. Different experiments were designed to determine the optimum age of the seedlings for the remediation process, and also to study the principal way in which the radionuclides are removed from the solution by the sunflower roots. In every trial a precipitate appeared which contained a major fraction of the natural uranium and 226 Ra. The results indicated that the seedlings themselves induced the formation of this precipitate. When four-week-old seedlings were exposed to contaminated water, a period of only 2 days was sufficient to remove the natural uranium and 226 Ra from the solution: about 50% of the natural uranium and 70% of the 226 Ra were fixed in the roots, and essentially the rest was found in the precipitate, with only very small percentages fixed in the shoots and left in solution

  10. Irradiation behaviour of mixed uranium-plutonium carbides, nitrides and carbonitrides; Comportement a l'irradiation de carbures, nitrures et carbonitrures mixtes d'uranium et de plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Mikailoff, H; Mustelier, J P; Bloch, J; Leclere, J; Hayet, L [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1967-07-01

    In the framework of the research program of fast reactor fuels two irradiation experiments have been carried out on mixed uranium-plutonium carbides, nitrides and carbo-nitrides. In the first experiment carried out with thermal neutrons, the fuel consisted of sintered pellets sheathed in a stainless steel can with a small gap filled with helium. There were three mixed mono-carbide samples and the maximum linear power was 715 W/cm. After a burn-up slightly lower than 20000 MW day/tonne, a swelling of the fuel which had ruptured the cans was observed. In the second experiment carried out in the BR2 reactor with epithermal neutrons, the samples consisted of sintered pellets sodium bonded in a stainless steel tube. There were three samples containing different fuels and the linear power varies between 1130 and 1820 W/cm. Post-irradiation examination after a maximal burn-up of 1550 MW day/tonne showed that the behaviour of the three fuel elements was satisfactory. (authors) [French] Dans le cadre du programme d'etude des conibustiles pour reacteurs rapides, on a realise deux experiences d'irradiation de carbures, nitrures et carbonitrures mixtes d'uranium et de plutonium. Dans la premiere experience, faite en neutrons thermiques, le combustible etait constitue de,pastilles frittees gainees dans un tube d'acier inoxydable avec un faible jeu rempli d'helium. Il y avait trois echantillons de monocarbures mixtes, et la puissance lineaire maximale etait de 715 W/cm. Apres un taux de combustion legerement inferieur a 20 000 MWj/t, on a observe un gonflement des combustible qui a provoque, la rupture des gaines. Pans la seconde experience, realisee dans le reacteur BR2 en neutrons epithermiques, les echantillons etaient constitues de pastilles frittees gainees dans un tube d'acier avec un joint sodium. Il y avait trois echantillons contenant des combustibles differents, et la puissance lineaire variait de 1130 a 1820 W/cm. Les examens apres irradiation a un taux maximal de

  11. A method for the quantitative determination of uranium-233 in an irradiated thorium rod; Une methode de dosage de l'uranium 233 contenu dans un barreau de thorium irradie

    Energy Technology Data Exchange (ETDEWEB)

    Bathellier, A; Sontag, R; Chesne, A [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1961-07-01

    A rapid method for the quantitative determination of uranium-233 in irradiated thorium is described. A 30 per cent solution of trilaurylamine in xylene is used to extract the uranium from an aqueous hydrochloric acid solution and separate it from the thorium. This may be followed by {alpha} counting or fluorimetry. The practical operating conditions of the separation are discussed in detail. (author) [French] Une methode rapide de dosage de l'uranium-233 contenu dans le thorium irradie est decrite. Elle utilise la trilauryfamine a 30 pour cent dans le xylene pour extraire l'uranium d'une dissolution aqueuse chlorhydrique et le separer du thorium. Le comptage {alpha} ou la fluorimetrie sont alors possibles. Les conditions operatoires de la separation sont discutees et precisees. (auteur)

  12. Uranium Biomineralization by Natural Microbial Phosphatase Activities in the Subsurface

    Energy Technology Data Exchange (ETDEWEB)

    Sobecky, Patricia A. [Univ. of Alabama, Tuscaloosa, AL (United States)

    2015-04-06

    In this project, inter-disciplinary research activities were conducted in collaboration among investigators at The University of Alabama (UA), Georgia Institute of Technology (GT), Lawrence Berkeley National Laboratory (LBNL), Brookhaven National Laboratory (BNL), the DOE Joint Genome Institute (JGI), and the Stanford Synchrotron Radiation Light source (SSRL) to: (i) confirm that phosphatase activities of subsurface bacteria in Area 2 and 3 from the Oak Ridge Field Research Center result in solid U-phosphate precipitation in aerobic and anaerobic conditions; (ii) investigate the eventual competition between uranium biomineralization via U-phosphate precipitation and uranium bioreduction; (iii) determine subsurface microbial community structure changes of Area 2 soils following organophosphate amendments; (iv) obtain the complete genome sequences of the Rahnella sp. Y9-602 and the type-strain Rahnella aquatilis ATCC 33071 isolated from these soils; (v) determine if polyphosphate accumulation and phytate hydrolysis can be used to promote U(VI) biomineralization in subsurface sediments; (vi) characterize the effect of uranium on phytate hydrolysis by a new microorganism isolated from uranium-contaminated sediments; (vii) utilize positron-emission tomography to label and track metabolically-active bacteria in soil columns, and (viii) study the stability of the uranium phosphate mineral product. Microarray analyses and mineral precipitation characterizations were conducted in collaboration with DOE SBR-funded investigators at LBNL. Thus, microbial phosphorus metabolism has been shown to have a contributing role to uranium immobilization in the subsurface.

  13. Uranium Biomineralization by Natural Microbial Phosphatase Activities in the Subsurface

    International Nuclear Information System (INIS)

    Sobecky, Patricia A.

    2015-01-01

    In this project, inter-disciplinary research activities were conducted in collaboration among investigators at The University of Alabama (UA), Georgia Institute of Technology (GT), Lawrence Berkeley National Laboratory (LBNL), Brookhaven National Laboratory (BNL), the DOE Joint Genome Institute (JGI), and the Stanford Synchrotron Radiation Light source (SSRL) to: (i) confirm that phosphatase activities of subsurface bacteria in Area 2 and 3 from the Oak Ridge Field Research Center result in solid U-phosphate precipitation in aerobic and anaerobic conditions; (ii) investigate the eventual competition between uranium biomineralization via U-phosphate precipitation and uranium bioreduction; (iii) determine subsurface microbial community structure changes of Area 2 soils following organophosphate amendments; (iv) obtain the complete genome sequences of the Rahnella sp. Y9-602 and the type-strain Rahnella aquatilis ATCC 33071 isolated from these soils; (v) determine if polyphosphate accumulation and phytate hydrolysis can be used to promote U(VI) biomineralization in subsurface sediments; (vi) characterize the effect of uranium on phytate hydrolysis by a new microorganism isolated from uranium-contaminated sediments; (vii) utilize positron-emission tomography to label and track metabolically-active bacteria in soil columns, and (viii) study the stability of the uranium phosphate mineral product. Microarray analyses and mineral precipitation characterizations were conducted in collaboration with DOE SBR-funded investigators at LBNL. Thus, microbial phosphorus metabolism has been shown to have a contributing role to uranium immobilization in the subsurface.

  14. Uranium mobility in the natural environment - evidence from sedimentary roll-front deposits

    International Nuclear Information System (INIS)

    Deutsch, W.J.; Serne, R.J.

    1983-04-01

    Roll-front deposits consist of naturally occurring ore-grade uranium in selected sandstone aquifers throughout the world. The geochemical environment of these roll-front deposits is analogous to the environment of a radioactive waste repository containing redox-sensitive elements during its post-thermal period. The ore deposits are formed by a combination of dissolution, complexation, sorption/precipitation, and mineral formation processes. The uranium, leached from the soil by percolating rainwater, complexes with dissolved carbonate and moves in the oxidizing ground water at very low concentration (parts per billion) levels. The uranium is extracted from the leaching solution by the chemical processes, over long periods of time, at the interfaces between oxidized and reduced sediments. The Eh of the ground water associated with the reduced sediments (Eh = -100 mv to +100 mv) is higher than the Eh expected for most waste repository environments (Eh = -100 mv to -300 mv); this suggests that uranium solids will not be very soluble in the repositories. Data from in-situ leach mining and restoration of roll-front uranium deposits also provide information on the potential mobility of the waste if oxidizing ground water should enter the repository. Uranium solids probably will be initially very soluble in carbonate ground water; however, as reducing conditions are re-estblished through water/rock interactions, the uranium will reprecipitate and the amount of uranium in solution will again equilibrate with the reduced uranium minerals

  15. Irradiation behavior of uranium-silicide dispersion fuels

    International Nuclear Information System (INIS)

    Hofman, G.L.; Neimark, L.A.

    1984-01-01

    This paper describes and analyzes the irradiation behavior of experimental fuel plates containing U 3 Si, U 3 Si-1.5 w/o Al, and U 3 Si 2 particulate fuel dispersed and clad in aluminum. The fuel is nominally 19.9%-enriched 235 U and the fuel volume fraction in the central ''meat'' section of the plates is approximately 33%. Sets of fuel plates were removed from the Oak Ridge Research reactor at burnup levels of 35, 83, and 94% 235 U depletion and examined at the Alpha-Gamma Hot-Cell Facility at Argonne National Laboratory. The results of the examination may be summarized as follows. The dimensional stability of the U 3 Si 2 and pure U 3 Si fuel was excellent throughout the entire burnup range, with uniform plate thickness increases up to a maximum of 4 mils at the highest burnup level (94% 235 U depletion). This corresponds to a meat volume increase of 11%. The swelling was partially due to solid fission products but to a larger extent to fission gas bubbles. The fission gas bubbles in U 3 Si 2 were small (submicrometer size) and very uniformly distributed, indicating great stability. To a large extent this was also the case for U 3 Si; however, larger bubbles ( 3 Si-1.5 w/o Al fuel became unstable at the higher burnup levels. Fission gas bubbles were larger than in the other two fuels and were present throughout the fuel particles. At 94% 235 U depletion, the formation of fission gas bubbles with diameters up to 20 mils caused the plates to pillow. It is proposed that aluminum in U 3 Si destabilizes fission gas bubble formation to the point of severe breakaway swelling in the prealloyed silicide fuel. (author)

  16. Evaluation of external and internal irradiation on uranium mining enterprise staff by tooth enamel EPR spectroscopy

    Science.gov (United States)

    Zhumadilov, Kassym; Ivannikov, Alexander; Khailov, Artem; Orlenko, Sergei; Skvortsov, Valeriy; Stepanenko, Valeriy; Kuterbekov, Kairat; Toyoda, Shin; Kazymbet, Polat; Hoshi, Masaharu

    2017-11-01

    In order to estimate radiation effects on uranium enterprise staff and population teeth samples were collected for EPR tooth enamel dosimetry from population of Stepnogorsk city and staff of uranium mining enterprise in Shantobe settlment (Akmola region, North of Kazakhstan). By measurements of tooth enamel EPR spectra, the total absorbed dose in the enamel samples and added doses after subtraction of the contribution of natural background radiation are determined. For the population of Stepnogorsk city average added dose value of 4 +/- 11 mGy with variation of 51 mGy was obtained. For the staff of uranium mining enterprise in Shantobe settlment average value of added dose 95 +/- 20 mGy, with 85 mGy variation was obtained. Higher doses and the average value and a large variation for the staff, probably is due to the contribution of occupational exposure.

  17. Gas Generation from K East Basin Sludges and Irradiated Metallic Uranium Fuel Particles Series III Testing

    International Nuclear Information System (INIS)

    Schmidt, Andrew J.; Delegard, Calvin H.; Bryan, Samuel A.; Elmore, Monte R.; Sell, Rachel L.; Silvers, Kurt L.; Gano, Susan R.; Thornton, Brenda M.

    2003-01-01

    The path forward for managing of Hanford K Basin sludge calls for it to be packaged, shipped, and stored at T Plant until final processing at a future date. An important consideration for the design and cost of retrieval, transportation, and storage systems is the potential for heat and gas generation through oxidation reactions between uranium metal and water. This report, the third in a series (Series III), describes work performed at the Pacific Northwest National Laboratory (PNNL) to assess corrosion and gas generation from irradiated metallic uranium particles (fuel particles) with and without K Basin sludge addition. The testing described in this report consisted of 12 tests. In 10 of the tests, 4.3 to 26.4 g of fuel particles of selected size distribution were placed into 60- or 800-ml reaction vessels with 0 to 100 g settled sludge. In another test, a single 3.72-g fuel fragment (i.e., 7150-mm particle) was placed in a 60 ml reaction vessel with no added sludge. The twelfth test contained only sludge. The fuel particles were prepared by crushing archived coupons (samples) from an irradiated metallic uranium fuel element. After loading the sludge materials (whether fuel particles, mixtures of fuel particles and sludge, or sludge-only) into reaction vessels, the solids were covered with an excess of K Basin water, the vessels closed and connected to a gas measurement manifold, and the vessels back-flushed with inert neon cover gas. The vessels were then heated to a constant temperature. The gas pressures and temperatures were monitored continuously from the times the vessels were purged. Gas samples were collected at various times during the tests, and the samples analyzed by mass spectrometry. Data on the reaction rates of uranium metal fuel particles with water as a function of temperature and particle size were generated. The data were compared with published studies on metallic uranium corrosion kinetics. The effects of an intimate overlying sludge layer

  18. Oxidation of naturally reduced uranium in aquifer sediments by dissolved oxygen and its potential significance to uranium plume persistence

    Science.gov (United States)

    Davis, J. A.; Smith, R. L.; Bohlke, J. K.; Jemison, N.; Xiang, H.; Repert, D. A.; Yuan, X.; Williams, K. H.

    2015-12-01

    The occurrence of naturally reduced zones is common in alluvial aquifers in the western U.S.A. due to the burial of woody debris in flood plains. Such reduced zones are usually heterogeneously dispersed in these aquifers and characterized by high concentrations of organic carbon, reduced mineral phases, and reduced forms of metals, including uranium(IV). The persistence of high concentrations of dissolved uranium(VI) at uranium-contaminated aquifers on the Colorado Plateau has been attributed to slow oxidation of insoluble uranium(IV) mineral phases found in association with these reducing zones, although there is little understanding of the relative importance of various potential oxidants. Four field experiments were conducted within an alluvial aquifer adjacent to the Colorado River near Rifle, CO, wherein groundwater associated with the naturally reduced zones was pumped into a gas-impermeable tank, mixed with a conservative tracer (Br-), bubbled with a gas phase composed of 97% O2 and 3% CO2, and then returned to the subsurface in the same well from which it was withdrawn. Within minutes of re-injection of the oxygenated groundwater, dissolved uranium(VI) concentrations increased from less than 1 μM to greater than 2.5 μM, demonstrating that oxygen can be an important oxidant for uranium in such field systems if supplied to the naturally reduced zones. Dissolved Fe(II) concentrations decreased to the detection limit, but increases in sulfate could not be detected due to high background concentrations. Changes in nitrogen species concentrations were variable. The results contrast with other laboratory and field results in which oxygen was introduced to systems containing high concentrations of mackinawite (FeS), rather than the more crystalline iron sulfides found in aged, naturally reduced zones. The flux of oxygen to the naturally reduced zones in the alluvial aquifers occurs mainly through interactions between groundwater and gas phases at the water table

  19. Radioactive wastes of uranium mining and milling: Radiological consequences for human population and natural environment

    International Nuclear Information System (INIS)

    Sazykina, T.G.; Kryshev, I.I.

    2002-01-01

    The sources of wastes and levels of radioactive contamination are considered in the areas of uranium ore mining and milling. Assessments of doses to the population are made using the methodology of multiple sources and pathways of exposure, including calculations of inhalation dose and doses from consumption of contaminated agricultural and natural products, as well as external exposure from the radioactive cloud and soil. On the local (0-100 km) spatial scale, the dose from uranium mining and processing is, on average, about 0.7 man Sv (GWa) -1 . The most significant pathway of the population exposure is inhalation of radon. The impact of uranium ore mining and processing on natural flora and fauna is determined by specific characteristics of the production at uranium mining enterprises and has both radiation and non-radiation components. The estimates of external and internal exposures to the natural biota in the vicinity of hydro-metallurgical works and tailing dumps are presented. (author)

  20. Calculation of oxygen distribution in uranium-plutonium oxide fuels during irradiation (programme CODIF)

    International Nuclear Information System (INIS)

    Moreno, A.; Sari, C.

    1978-01-01

    Radial gradients of oxygen to metal ratio, O/M, in uranium-plutonium oxide fuel pins, during irradiation and at the end of life, have been calculated on the basis of solid-state thermal diffusion using measured values of the heat of transport. A detailed computer model which includes the calculation of temperature profiles and the variation of the average O/M ratio as a function of burn-up is given. Calculations show that oxygen profiles are affected by the isotopic composition of the fuel, by the temperature profiles and by fuel-cladding interactions

  1. The relationship between natural uranium and advanced fuel cycles in CANDU reactors

    International Nuclear Information System (INIS)

    Lane, A.D.; McDonnell, F.N.; Griffiths, J.

    1988-11-01

    CANDU is the most uranium-economic type of thermal power reactor, and is the only type used in Canada. CANDU reactors consume approximately 15% of Canadian uranium production and support a fuel service industry valued at ∼$250 M/a. In addition to their once-through, natural-uranium fuel cycle, CANDU reactors are capable of operating with slightly-enriched uranium (SEU), uranium-plutonium and thorium cycles, more efficiently than other reactors. Only SEU is economically attractive in Canada now, but the other cycles are of interest to countries without indigenous fuel resources. A program is underway to establish the fuel technologies necessary for the use of SEU and the other fuel cycles in CANDU reactors. 22 refs

  2. The shielded chemistry suite at BNL and its use in the study of the irradiated uranium-water reaction

    International Nuclear Information System (INIS)

    Bannister, G.H.; Tyfield, S.P.

    1977-11-01

    A versatile shielded facility for chemical studies is now in use at Berkeley Nuclear Laboratories. The suite was fully commissioned in 1976 and first utilised to study the aqueous corrosion of irradiated reactor grade uranium. The suite consists of three adjacent interconnected cells; a balance cell, a preparation cell and an experimental cell. The development, design and layout of the facilities are described, as are the details of the equipment installed to undertake a uranium corrosion study. The preparation cell is used for procedures that could results in high levels of contamination, such as cutting of uranium specimens. The uranium samples are corroded in sealed steel capsules installed in the experimental cell. The capsules are heated either isothermally or through a transient and the reaction monitored with a pressure transducer which records the rate of hydrogen evolution from the uranium-water reaction. The experimental results will be reported elsewhere. (author)

  3. Experimental studies of neutron irradiated uranium dioxide at high temperatures

    International Nuclear Information System (INIS)

    Tanke, R.H.J.

    1990-01-01

    In case of an accident situation, in which the heat of the nuclear fuel can no longer be transferred to coolin water, the temperature of the nuclear fuel ay rise very strongly, so that radioactive fission products may be released, which can ultimately lead to the release of radioactive substances to the environment. In this respect it is important to know more about the release rate of the various fission products and their fuel samples, used in the investigation, were UO-2 spheres of approximately 1 mm. The chemical forms of the particles which are being released from the sphees during evaporation have been determined using a mass spectrometer. At the same time, the activity of the fission products has been measured using a gamma spectrometer. A gamma tomographer has been developed for determining the three-dimensional distribution of the concentration of radioactive fission products in the sphere. With this tomographer the change of this distribution as a function of temperature could be measured. For interpretation of the results two models have been developed: a model of the evaporation of the non-stoichiometric UO-2, and a model of the diffusion of fission products in UO-2. The first model was used to determine the stoichiometry of the sphere while the second has been used to determine the activation energy for the diffusion of the fission products. The main conclusion is that the microstructure of the nuclear fuel has a great effect on both the amount of free oxygen atoms, the release rate and the chemical form of fission products. This microstructure has not been investigated in greater detail so that all other conclusions are of qualitative nature. (author). 111 refs.; 114 figs.; 13 tabs

  4. Exposure pathways and health effects associated with chemical and radiological toxicity of natural uranium: a review.

    Science.gov (United States)

    Brugge, Doug; de Lemos, Jamie L; Oldmixon, Beth

    2005-01-01

    Natural uranium exposure derives from the mining, milling, and processing of uranium ore, as well as from ingestion of groundwater that is naturally contaminated with uranium. Ingestion and inhalation are the primary routes of entry into the body. Absorption of uranium from the lungs or digestive track is typically low but can vary depending on compound specific solubility. From the blood, two-thirds of the uranium is excreted in urine over the first 24 hours and up to 80% to 90% of uranium deposited in the bone leaves the body within 1.5 years. The primary health outcomes of concern documented with respect to uranium are renal, developmental, reproductive, diminished bone growth, and DNA damage. The reported health effects derive from experimental animal studies and human epidemiology. The Lowest Observed Adverse Effect Level (LOAEL) derived from animal studies is 50 microg/m3 for inhalation and 60 ug/kg body weight/day for ingestion. The current respiratory standard of the Occupational Safety and Health Administration (OSHA), 50 microg/m3, affords no margin of safety. Considering the safety factors for species and individual variation, the ingestion LOAEL corresponds to the daily consumption set by the World Health Organization Drinking Water Standard at 2 microg/L. Based on economic considerations, the United States Environmental Protection Agency maximum contaminant level is 30 microg/L. Further research is needed, with particular attention on the impact of uranium on indigenous populations, on routes of exposure in communities near uranium sites, on the combined exposures present at many uranium sites, on human developmental defects, and on health effects at or below established exposure standards.

  5. The migration of intra-granular fission gas bubbles in irradiated uranium dioxide

    International Nuclear Information System (INIS)

    Baker, C.

    1977-05-01

    The mobility of intragranular fission gas bubbles in uranium dioxide irradiated at 1600-1800 0 C has been studied following isothermal annealing at temperatures below 1600 0 C. The intragranular fission gas bubbles, average diameter approximately 2nm, are virtually immobile at temperatures below 1500 0 C. The bubbles have clean surfaces with no solid fission product contamination and are faceted to the highest observed irradiation temperature of 1800 0 C. This bubble faceting is believed to be a major cause of bubble immobility. In fuel operating below 1500 0 C the predominant mechanism allowing the growth of intragranular bubbles and the subsequent gas release must be the diffusion of dissolved gas atoms rather than the movement of entire intragranular bubbles. (author)

  6. Chemical states of fission products in irradiated uranium-plutonium mixed oxide fuel

    International Nuclear Information System (INIS)

    Kurosaki, Ken; Uno, Masayoshi; Yamanaka, Shinsuke

    1999-01-01

    The chemical states of fission products (FPs) in irradiated uranium-plutonium mixed oxide (MOX) fuel for the light water reactor (LWR) were estimated by thermodynamic equilibrium calculations on system of fuel and FPs by using ChemSage program. A stoichiometric MOX containing 6.1 wt. percent PuO 2 was taken as a loading fuel. The variation of chemical states of FPs was calculated as a function of oxygen potential. Some pieces of information obtained by the calculation were compared with the results of the post-irradiation examination (PIE) of UO 2 fuel. It was confirmed that the multicomponent and multiphase thermodynamic equilibrium calculation between fuel and FPs system was an effective tool for understanding the behavior of FPs in fuel. (author)

  7. Studies on the separation and purification of uranium from thoria irradiated in PHWR

    International Nuclear Information System (INIS)

    Kedari, C.S.; Sinalkar, N.; Dhami, P.S.; Achuthan, P.V.; Vijayan, K.; Moorthy, A.D.; Jambunathan, U.; Munshi, S.K.; Dey, P.K.

    2005-10-01

    About 5 g of thoria pellet extracted from the thoria bundle irradiated to 508 full power days in PHWR at KAPS and cooled for about 4.5 years was dissolved in 25 mL of 13 M HNO 3 containing 0.03 M HF and 0.1 M Al(NO 3 ) 3 under reflux condition in a shielded glove box. Thorium concentration and acidity of the dissolved solution was adjusted to ∼97 g/L and 4M HNO 3 , suitable for solvent extraction studies. The feed solution had a uranium concentration of 1.36 g/L and gross gamma activity of ∼6 Ci/L. Liquid-liquid extraction experiments were carried out in batch with this feed using 3% TBP in n-dodecane as extractant. The uranium product solution obtained from the solvent extraction was further purified by ion-exchange method using cation exchange resin Dowex 50 x 4. Fission product activity and the isotopic composition of the final recovered product were measured. The uranium product had an overall decontamination factor of 10 4 and 2 x 10 4 with respect to thorium and fission product activity respectively. A part of the solution was monitored for dose build-up due to the growth of the decay products of 232 U which is a vital input for designing the shielding of a 233 U separation facility. (author)

  8. Irradiation behavior of uranium-molybdenum dispersion fuel: Fuel performance data from RERTR-1 and RERTR-2

    International Nuclear Information System (INIS)

    Meyer, M.K.; Clark, C.R.; Hayes, S.L.; Strain, R.V.; Hofman, G.L.; Snelgrove, J.L.; Park, J.M.; Kim, K.H.

    1999-01-01

    This paper presents quantitative data on the irradiation behavior of uranium-molybdenum fuels from the low temperature RERTR-1 and -2 experiments. Fuel swelling measurements of U-Mo fuels at ∼40% and ∼70% burnup are presented. The rate of fuel-matrix interaction layer growth is estimated. Microstructures of fuel in the pre- and postirradiation condition were compared. Based on these data, a qualitative picture of the evolution of the U-Mo fuel microstructure during irradiation has been developed. Estimates of uranium-molybdenum fuel swelling and fuel-matrix interaction under high-power research reactor operating conditions are presented. (author)

  9. On the use of thin natural uranium film dosimetry in mineral dating by the fission track method

    International Nuclear Information System (INIS)

    Hadler Neto, J.C.; Iunes, P.J.; Khouri, M.C.

    1993-01-01

    Three obsidian samples were irradiated in a neutron facility and their age was measured by the fission track method; using a thin uranium film dosemeter. The results were compared to others made previously on the same type of rock using conventional neutron dosimetry. The use of thin uranium film for age determination is discussed. (F.E.). 20 refs, 4 tabs

  10. Research on calculation of mixing fraction for natural uranium equivalent fuel

    International Nuclear Information System (INIS)

    Huang Shien; Wang Lianjie; Wei Yanqin; Li Qing; Zheng Jiye

    2013-01-01

    Based on the first-order perturbation theory and reasonable approximations, the calculation method of recycled uranium (RU) and depleted uranium (DU) mixing fraction for natural uranium equivalent (NUE) fuel was studied, so the equivalence between NUE fuel and natural uranium (NU) fuel was assured. The adopted calculation method accurately takes the variation of micro cross sections alone with fuel depletion into account. A computer code named ALPHA was programmed to execute the calculation procedure. Then the ALPHA code and the WIMS-AECL code compose a processing system, which is applicable to the mixing fraction calculation for heavy water reactor NUE fuel. The validation shows that the processing system can accurately calculate the mixing fraction for NUE fuel. (authors)

  11. Uranium

    International Nuclear Information System (INIS)

    Whillans, R.T.

    1981-01-01

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

  12. Irradiation performance of helium-bonded uranium--plutonium carbide fuel elements

    International Nuclear Information System (INIS)

    Latimer, T.W.; Petty, R.L.; Kerrisk, J.F.; DeMuth, N.S.; Levine, P.J.; Boltax, A.

    1979-01-01

    The current irradiation program of helium-bonded uranium--plutonium carbide elements is achieving its original goals. By August 1978, 15 of the original 171 helium-bonded elements had reached their goal burnups including one that had reached the highest burnup of any uranium--plutonium carbide element in the U.S.--12.4 at.%. A total of 66 elements had attained burnups over 8 at.%. Only one cladding breach had been identified at that time. In addition, the systematic and coordinated approach to the current steady-state irradiation tests is yielding much needed information on the behavior of helium-bonded carbide fuel elements that was not available from the screening tests (1965 to 1974). The use of hyperstoichiometric (U,Pu)C containing approx. 10 vol% (U,Pu) 2 C 3 appears to combine lower swelling with only a slightly greater tendency to carburize the cladding than single-phase (U,Pu)C. The selected designs are providing data on the relationship between the experimental parameters of fuel density, fuel-cladding gap size, and cladding type and various fuel-cladding mechanical interaction mechanisms

  13. Neutron irradiated uranium silicides studied by neutron diffraction and Rietveld analysis

    International Nuclear Information System (INIS)

    Birtcher, R.C.; Mueller, M.H.; Richardson, J.W. Jr.; Faber, J. Jr.

    1989-11-01

    Uranium silicides have been considered for use as reactor fuels in both high power and low enrichment applications. However, U 3 Si was found to become amorphous under irradiation and to become mechanically unstable to rapid growth by plastic flow. U 2 Si 2 appears to be stable against amorphization at low displacement rates, but the extent of this stability is uncertain. Although the mechanisms responsible for plastic flow in U 3 Si and other amorphous systems are unknown, as is the importance of crystal structure for amorphization, it may not be surprising that these materials amorphize, in light of the fact that many radioactive nuclide - containing minerals are known to metaminctize (lose crystallinity) under irradiation. The present experiment follows the detailed changes in the crystal structures of U 3 Si and U 3 Si 2 introduced by neutron bombardment and subsequent uranium fission at room temperature. U-Si seems the ideal system for a neutron diffraction investigation since the crystallographic and amorphous forms can be studied simultaneously by combining conventional Rietveld refinement of the crystallographic phases with Fourier-filtering of the non-crystalline scattering component

  14. Antioxidant properties of natural substances in irradiated fresh poultry

    International Nuclear Information System (INIS)

    Mahrour, A.; Lacroix, M.; Nketsa-Tabiri, J.; Calderon, N.; Gagnon, M.

    1998-01-01

    This study was undertaken to determine if a combined treatment (marinating in natural plant extracts or vacuum) with irradiation could have a synergistic effect, in order to prevent the lipid oxidation resulting in the development of undesirable flavours. The fresh chicken legs were irradiated at 0,3 and 5 kGy. The fatty acids composition of lipids was identified using gas liquid chromatography. The effect of irradiation treatment combined with a pre-treatment on the fatty acids composition was followed. The day after irradiation, ten panallists were asked to evaluate, using the instruction scaling, the overall appearance, the odor, the flavor and the overall acceptability of the samples. The major fatty acids identified in lipids were oleic acid, palmitic acid, palmitoleic acid and stearic acid. Pre-treatments have a significant effect on linoleic acid (C18:2) and higher fatty acids. The unsaturated fatty acids derived from phospholipids appeared to be more affected by the irradiation dose: however, marinating have better protection on C18:2 derived from phospholipids. The results of sensory evaluation have shown a significant better odor and flavor for the irradiated chicken at 5 kGy than the control. No significant difference have been found between the marinated chicken, the chicken irradiated under vacuum and the control

  15. Case history of natural analogue research on sandstone type uranium occurrences, Japan

    International Nuclear Information System (INIS)

    Sakamaki, Y.; Kanai, Y.

    1991-01-01

    Previous fundamental studies on the ore genesis of uranium occurrences chiefly in Cenozoic sandstone formations in Japan, have been re-examined as the case history on natural analogue of radionuclides in high-level radioactive wastes (HLRW). Two principal mode of occurrences have been distinguished among Cenozoic uranium localities in Japan. In the Setouchi (Inland Sea) subregion, hot-spots are found in lacustrine to shallow sea facies of calm environment, corresponding to the first stage of formation of tectonic basins. As observed in Ningyo-toge and Tono area, stratabound ore bodies are generally arranged into paleo-channels. Another type of sporadic uranium indications are found within collapse basins in the 'Green-tuff' subregion, where intense volcanisms and block movements had been taken places throughout Middle miocene age. Well-developed fractures were to be favorable paths for uraniferous groundwater, as well as the suitable site for deposition of uranium. In both cases, the source material of uranium is granitic basement. Under oxidizing environment, uranium anomalies have been occasionally detected in surface- or fracture waters which passing through decomposed granite. In contrast to the behavior of uranium, one of the adequate analogues for mobile nuclides, thorium and REE are relatively immobile even under the same geologic and geochemical circumstances. In ore horizon, where reducing condition has still been kept, geochronological age of tetravalent uranium mineral is in concordance with the age of the host rock. Analysis of structural control shows that the principal factors for uranium concentration are the layout of redox front related to paleo-water tables. 234U/238U disequilibrium method has been proved to be the powerful tool for detecting mobility of uranium in the host rock throughout diagenesis and weathering process. The result of field and laboratory works on this is reported as an example. (author)

  16. Determination of natural and depleted uranium in urine at the ppt level: an interlaboratory analytical exercise

    International Nuclear Information System (INIS)

    D'Agostino, P.A.; Ough, E.A.; Glover, S.E.; Vallerand, A.L.

    2002-10-01

    An analytical exercise was initiated in order to determine those analytical procedures with the capacity to measure uranium isotope ratios ( 238 U/ 235 U) in urine samples containing less that 1μ uranium /L urine. A host laboratory was tasked with the preparation of six sets (12 samples per set) of synthetic urine samples spiked with varying amounts of natural and depleted (0.2% 235 U) uranium. The sets of samples contained total uranium in the range 25 ng U/L urine to 770 ng U/L urine, with isotope ratios ( 238 U/ 235 U) from 137.9 (natural uranium) to 215 (∼50% depleted uranium). Sets of samples were shipped to five testing laboratories (four Canadian and one European) for total and isotopic assay. The techniques employed in the analyses included sector field inductively coupled plasma mass spectrometry (ICP-SF-MS), quadrupole inductively coupled plasma mass spectrometry (ICP-Q-MS), thermal ionization mass spectrometry (TIMS) and neutron activation analysis (NAA). Full results were obtained from three testing labs (ICP-SF-MS, ICP-Q-MS and TIMS). Their results, plus partial results from the NAA lab, have been included in this report. Total uranium and isotope ratio results obtained from ICP-SF-MS and ICP-Q-MS were in good agreement with the host lab values. Neutron activation analysis and TIMS reported total uranium concentrations that differed from the host lab. An incomplete set of isotopic ratios was obtained from the NAA lab with some results reporting enriched uranium (% 235 U > 0.7). Based on the reported results, the four analytical procedures were ranked: ICP-SF-MS (1), ICP-Q-MS (2), TIMS (3) and NAA (4). (author)

  17. Study on removal effect and mechanism of uranium by hydroxyapatite and natural apatite

    International Nuclear Information System (INIS)

    Zhang Xiaofeng; Chen Diyun; Tu Guoqing; Huang Xiaozhui

    2014-01-01

    By the static experiments, the effects of reaction time, pH value, initial concentration of uranium, dosage of apatite on adsorption of hydroxyapatite and natural apatite for uranium were studied respectively. The adsorption process was analyzed by thermodynamics and kinetics, and the adsorption mechanism was analyzed by infrared spectroscopy, X-ray diffraction and scanning electron microscope. The results of hydroxyapatite show that the removal capacity of uranium increases with the initial concentration of uranium, and the adsorption rate of hydroxyapatite on UO_2"2"+ reaches 85%, when the pH value is 4 to 5 and dosage of hydroxyapatite is 0.75 g. The results of natural apatite show that the removal capacity of uranium increases with the initial concentration of uranium, and the adsorption rate of natural apatite on UO_2"2"+ is up to 80%, when the pH value is 3 and dosage of hydroxyapatite is l.0 g. Similarly, at 120 minutes both of the removal reactions by hydroxyapatite and natural apatite substantially reach equilibrium. Moreover, both of the reactions by hydroxyapatite and natural apatite are in line with quasi secondary dynamics equation, and follow the Langmuir adsorption isotherm. Infrared spectra indicate that the removal of hydroxyapatite for uranium depends on the complexation of phosphate, which is almost the same as that of natural apatite. X-ray diffraction analysis shows that hydroxyapatite has the composition and structure of pure material, whereas the natural apatite is mainly composed of Ca_5H_2(PO_4)_3F and Ca_8H_2(PO_4)_6H_2O. In addition, scanning electron microscope demonstrates that hydroxyapatite has the appearance of spherical with a hole and the hole has a cavity containing a large amount of floc, while the surface becomes smooth and pores are closed after removal of uranium, which is due to the adsorption of UO_2"2"+ leading a link between molecules on hydroxyapatite surface. But for natural apatite, it depicts the angular mineral shape

  18. Uranium and radium geochemistry. Radioactive disequilibrium in natural waters

    International Nuclear Information System (INIS)

    Beaucaire, C.

    1987-09-01

    Rock-water interactions play a primary part in uranium-series disequilibrium either by different chemical behavior or by recoiling alpha emitting nuclei in solution. Three series of thermal water containing CO 2 (Vichy, Vals and Cezallier) and one from Lodeve uranium deposit are studied to define parameters (pH, Eh, pCO 2 , T,...) controlling studied nuclei. For U complexation by carbonates is in competition with redox conditions. Ra is coprecipitated by barium. For thermal waters keeping their deep characteristics there is a low disequilibriums 234 U- 238 U between 1 and 2. On the contrary important disequilibrium (up to 12) in Vichy Saint Yorre water are due to secondary remobilization. In the same way for these waters 234 U and 226 Ra are correlated. Then leaching is essential for the radioactive disequilibrium but alpha recoil of 234 Th is of secondary importance in this case [fr

  19. Natural uranium lattice in heavy water; Reseaux uranium naturel-eau lourde

    Energy Technology Data Exchange (ETDEWEB)

    Girard, Y; Koechlin, J C; Moreau, J; Naudet, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1959-07-01

    all solid bars are considered and n an d the effective integrals are adjusted then a system of transposition of these results to more complex bars is sought. In the second step, one is compelled to improve the system in studying in greater detail each factor of the calculation of the lattice. A satisfactory interpretation of the results leads definitively to methods of calculation applicable to the most varied types of natural uranium-heavy water lattices. Attention has been given to results obtained in other countries, particularly in Canada. (author) [French] Un ensemble de mesures de Laplaciens a ete realise en regime critique dans une pile a eau lourde construite specialement a cette fin, soit sur reseaux complets, soit sur echantillons de reseaux par une methode a deux zones. L'appareillage experimental est brievement decrit: il a ete etudie pour permettre des modifications rapides du chargement. On decrit egalement sommairement les methodes de mesure: on opere soit par cartes de flux, sur des reseaux qui servent ensuite de reference soit par remplacement progressif des barres par couronnes concentriques et mesures de reactivite. Dans ce cas, on cherche a atteindre l'ecart entre le laplacien-matiere du reseau central inconnu et celui du reseau de reference. La methode a fait l'objet d'une mise au point destinee a la rendre precice. On donne les resultats des mesures de laplaciens pour tous ces types de reseaux, ce qui permet de construire un ensemble de courbes en fonction du pas. Divers effets ont ete egalement mesure: equivalent en reactivite du millimetre d'eau - anisotropie - effet de temperature, etc. On a cependant prefere, dans cette premiere campagne de mesures tout au moins, obtenir une grande variete de laplaciens plutot que des mesures fines dans des cas particuliers. C'est dans cet esprit qu'a ete conduite l'interpretation des resultats. Nombre de phenomenes tres complexes echappant encore a nos possibilites de calcul, on estime qu'un certain nombre d

  20. Natural uranium lattice in heavy water; Reseaux uranium naturel-eau lourde

    Energy Technology Data Exchange (ETDEWEB)

    Girard, Y.; Koechlin, J.C.; Moreau, J.; Naudet, R. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1959-07-01

    all solid bars are considered and n an d the effective integrals are adjusted then a system of transposition of these results to more complex bars is sought. In the second step, one is compelled to improve the system in studying in greater detail each factor of the calculation of the lattice. A satisfactory interpretation of the results leads definitively to methods of calculation applicable to the most varied types of natural uranium-heavy water lattices. Attention has been given to results obtained in other countries, particularly in Canada. (author) [French] Un ensemble de mesures de Laplaciens a ete realise en regime critique dans une pile a eau lourde construite specialement a cette fin, soit sur reseaux complets, soit sur echantillons de reseaux par une methode a deux zones. L'appareillage experimental est brievement decrit: il a ete etudie pour permettre des modifications rapides du chargement. On decrit egalement sommairement les methodes de mesure: on opere soit par cartes de flux, sur des reseaux qui servent ensuite de reference soit par remplacement progressif des barres par couronnes concentriques et mesures de reactivite. Dans ce cas, on cherche a atteindre l'ecart entre le laplacien-matiere du reseau central inconnu et celui du reseau de reference. La methode a fait l'objet d'une mise au point destinee a la rendre precice. On donne les resultats des mesures de laplaciens pour tous ces types de reseaux, ce qui permet de construire un ensemble de courbes en fonction du pas. Divers effets ont ete egalement mesure: equivalent en reactivite du millimetre d'eau - anisotropie - effet de temperature, etc. On a cependant prefere, dans cette premiere campagne de mesures tout au moins, obtenir une grande variete de laplaciens plutot que des mesures fines dans des cas particuliers. C'est dans cet esprit qu'a ete conduite l'interpretation des resultats. Nombre de phenomenes tres complexes echappant encore a nos possibilites de

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

    International Nuclear Information System (INIS)

    1983-01-01

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

  2. The fluorimetry for control of internal contamination of exposed workers to natural and enriched uranium

    International Nuclear Information System (INIS)

    Gaburo, J.C.; Todo, A.S.; Sordi, G.M.A.A.

    2000-01-01

    This study is a part of bioassay program revision applied to the uranium processing plants at IPEN-CNEN/SP. The workers of these facilities handle both natural uranium and uranium compounds with different isotopic composition which could reach up to 20% in 235 U. The most commonly employed techniques for the determination of uranium in urine at IPEN are fluorimetry and alpha spectrometry with detection limit of 1.0 mgL-1. and 1,0 mBqL-1 , respectively. Based in advantages and disadvantages of each technique it is very important to identify the workers groups that should be submitted for these analysis. In this report a limiting value of uranium concentration in urine, mgL-1, obtained by fluorimetry is proposed. All the results greater than these limiting value indicate the necessity to carry out a additional measurement by alpha spectroscopy. The uranium mass that result in a pre-determined limit committed effective dose is function of isotopic composition. Consequently, the predicted value of the measured of urinary excretion is function of isotopic composition also and depends of absorption characteristics when inhaled and of the monitoring interval considered. In this report the uranium concentration values for reference levels and limits doses are determined. Based on these results the procedures to use the fluorimetry or both fluorimetry and alpha-spectrometry were adopted. (author)

  3. Uranium redistribution under oxidizing conditions in Oklo natural reactor zone 2, Gabon

    International Nuclear Information System (INIS)

    Isobe, H.; Ohnuki, T.; Murakami, T.; Gauthier-Lafaye, F.

    1995-01-01

    This mineralogical study was completed to elucidate the relationships between uranium distribution and alteration products of the host rock of natural reactor zone clays just below the reactor core. Uraninite is preserved without any alteration in the reactor core. Uranium minerals are found to be present in the fractures in the reactor zone clays associated with iron-mineral veins, galena and Ti-bearing minerals. Uranium, for which the phases could not be identified, occurs in iron-mineral veins and the iron-mineral rim of pyrite grains in the reactor zone clays. Uranium is not associated with granular iron minerals occurring in the illite matrix of the reactor zone clays. The degree of crystallinity and uranium content of the three iron-bearing alteration products suggest that they formed under different conditions; the granular iron minerals, under alteration conditions where uranium was not mobilized while the iron-mineral veins and the iron-mineral rim of pyrite, under conditions in which uranium is mobilized after the formation of the granular iron minerals

  4. 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.)

  5. Uranium

    Energy Technology Data Exchange (ETDEWEB)

    Williams, R M

    1976-01-01

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

  6. Aquifer restoration at in-situ leach uranium mines: evidence for natural restoration processes

    International Nuclear Information System (INIS)

    Deutsch, W.J.; Serne, R.J.; Bell, N.E.; Martin, W.J.

    1983-04-01

    Pacific Northwest Laboratory conducted experiments with aquifer sediments and leaching solution (lixiviant) from an in-situ leach uranium mine. The data from these laboratory experiments and information on the normal distribution of elements associated with roll-front uranium deposits provide evidence that natural processes can enhance restoration of aquifers affected by leach mining. Our experiments show that the concentration of uranium (U) in solution can decrease at least an order of magnitude (from 50 to less than 5 ppM U) due to reactions between the lixiviant and sediment, and that a uranium solid, possibly amorphous uranium dioxide, (UO 2 ), can limit the concentration of uranium in a solution in contact with reduced sediment. The concentrations of As, Se, and Mo in an oxidizing lixiviant should also decrease as a result of redox and precipitation reactions between the solution and sediment. The lixiviant concentrations of major anions (chloride and sulfate) other than carbonate were not affected by short-term (less than one week) contact with the aquifer sediments. This is also true of the total dissolved solids level of the solution. Consequently, we recommend that these solution parameters be used as indicators of an excursion of leaching solution from the leach field. Our experiments have shown that natural aquifer processes can affect the solution concentration of certain constituents. This effect should be considered when guidelines for aquifer restoration are established

  7. The separation of uranium ions by natural and modified diatomite from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Sprynskyy, Myroslav, E-mail: sprynsky@yahoo.com [Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University, 7 Gagarina Str., 87-100 Torun (Poland); Kovalchuk, Iryna [Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University, 7 Gagarina Str., 87-100 Torun (Poland); Institute of Adsorption and Problem of Endoecology, National Academy of Sciences of Ukraine, 13 General Naumov Str., 03164 Kyiv (Ukraine); Buszewski, Boguslaw [Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University, 7 Gagarina Str., 87-100 Torun (Poland)

    2010-09-15

    In this work the natural and the surfactant modified diatomite has been tested for ability to remove uranium ions from aqueous solutions. Such controlling factors of the adsorption process as initial uranium concentration, pH, contact time and ionic strength have been investigated. Effect of ionic strength of solution has been examined using the solutions of NaCl, Na{sub 2}CO{sub 3} and K{sub 2}SO{sub 4}. The pseudo-first order and the pseudo-second order models have been used to analyze the adsorption kinetic results, whereas the Langmuir and the Freundlich isotherms have been used to the equilibrium adsorption data. The effects of the adsorbent modification as well as uranium adsorption on the diatomite surface have been studied using X-ray powder diffraction, scanning electron microscopy and FTIR spectroscopy. The maximum adsorption capacities of the natural and the modified diatomite towards uranium were 25.63 {mu}mol/g and 667.40 {mu}mol/g, respectively. The desorptive solutions of HCl, NaOH, Na{sub 2}CO{sub 3}, K{sub 2}SO{sub 4}, CaCO{sub 3}, humic acid, cool and hot water have been tested to recover uranium from the adsorbent. The highest values of uranium desorption (86%) have been reached using 0.1 M HCl.

  8. The separation of uranium ions by natural and modified diatomite from aqueous solution.

    Science.gov (United States)

    Sprynskyy, Myroslav; Kovalchuk, Iryna; Buszewski, Bogusław

    2010-09-15

    In this work the natural and the surfactant modified diatomite has been tested for ability to remove uranium ions from aqueous solutions. Such controlling factors of the adsorption process as initial uranium concentration, pH, contact time and ionic strength have been investigated. Effect of ionic strength of solution has been examined using the solutions of NaCl, Na(2)CO(3) and K(2)SO(4). The pseudo-first order and the pseudo-second order models have been used to analyze the adsorption kinetic results, whereas the Langmuir and the Freundlich isotherms have been used to the equilibrium adsorption data. The effects of the adsorbent modification as well as uranium adsorption on the diatomite surface have been studied using X-ray powder diffraction, scanning electron microscopy and FTIR spectroscopy. The maximum adsorption capacities of the natural and the modified diatomite towards uranium were 25.63 micromol/g and 667.40 micromol/g, respectively. The desorptive solutions of HCl, NaOH, Na(2)CO(3), K(2)SO(4), CaCO(3), humic acid, cool and hot water have been tested to recover uranium from the adsorbent. The highest values of uranium desorption (86%) have been reached using 0.1M HCl. Copyright 2010 Elsevier B.V. All rights reserved.

  9. Idaho National Engineering Laboratory materials in inventory natural and enriched uranium management and storage costs

    International Nuclear Information System (INIS)

    Nebeker, R.L.

    1995-11-01

    On July 13, 1994, the Office of Environmental Management (EM) was requested to develop a planning process that would result in management policies for dealing with nuclear materials in inventory. In response to this request, EM launched the Materials In Inventory (MIN) Initiative. A Headquarters Working Group was established to develop the broad policy framework for developing MIN management policies. MIN activities cover essentially all nuclear materials within the DOE complex, including such items as spent nuclear fuel, depleted uranium, plutonium, natural and enriched uranium, and other materials. In August 1995, a report discussing the natural and enriched uranium portion of the Initiative for the Idaho National Engineering Laboratory (INEL) was published. That report, 'Idaho National Engineering Laboratory Materials-in-Inventory, Natural and Enriched Uranium'.' identified MIN under the control of Lockheed Idaho Technologies Company at the INEL. Later, additional information related to the costs associated with the storage of MIN materials was requested to supplement this report. This report provides the cost information for storing, disposing, or consolidating the natural and enriched uranium portion of the MIN materials at the INEL. The information consists of eight specific tables which detail present management costs and estimated costs of future activities

  10. Improving the Assessment of Internal Occupational Exposure to Natural Uranium from Urinalysis by Normalization to Creatinine

    International Nuclear Information System (INIS)

    Marko, R.; Kol, R.; Katorza, E.; German, U.; Balaish, Y.; Lorber, A.; Karpas, Z.

    2002-01-01

    The assessment of occupational internal exposure to natural uranium is normally carried out by combining Uranium Lung Detection (ULD) and urine analysis. The ULD is a direct measurement of the uranium content in lungs. The urine analysis measures the amount of uranium excreted from the body. The biokinetic models that are in use for dose assessments from urine analysis measurements are usually based on 24-hour urine collection. There are three traditional methods to collect urine samples: a) 24-hour collection - the subject is asked to collect all the urine excreted during a 24-hour period. b) Simulated 24-hour collection - the subject collects all the urine excreted during three consecutive 8-hour workdays. c) Spot samples - the subject gives a single urine sample at some time during work hours

  11. The theory and uses of natural uranium isotopic variations in hydrology

    International Nuclear Information System (INIS)

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

    1976-01-01

    The dissolved concentration of uranium and the relative abundance of two uranium isotopes, 234 U and 238 U, vary over a wide range of values in natural waters. The concentration is controlled mainly by the redox potential of the environment and by CO 2 . The mechanism of isotope fractionation is thought to be entrainment of 234 U in the aqueous phase either by selective leaching of the solid phase or by direct recoil of the daughter nuclide. Ion exchange techniques and alpha-spectrometry permit the measurement of uranium at concentrations as low as pp 10 11 and the isotopic ratio to a few per cent. In oxidizing conditions the uranium isotopes behave in a chemically stable conservative manner such that separate groundwater sources may have identifiably different characteristics and mixing volume calculations may be made. Other potential use of these isotopes include radiometric dating, tracing of hydrologic systems, ore prospecting and earthquake prediction. (author)

  12. LED vs laser fluorimetry: a comparative study for the determination of uranium in natural waters

    International Nuclear Information System (INIS)

    Shenoy, N.; Parab, H.; Sounderajan, S.; Kiran Kumar; Kumar, S.D.; Reddy, A.V.R.

    2015-01-01

    Measurement of uranium in water samples has acquired considerable importance ever since its occurrence in drinking water sources was reported. Among the various methods available for uranium quantification at ultra trace levels, laser fluorimetry (LF) method is the method of choice due to its simplicity, speed and high sensitivity compared to other analytical techniques. This technique is based on the measurement of fluorescence of uranium complexes in aqueous solution. Recently, laser source has been replaced by light emitting diode (LEDs) in the fluorimeter systems. In comparison to laser source, LED source is, cost effective, generates less heat and has extended lifetime. Herein, authors have presented a comparison of LED based fluorimeter (Quantalase, Indore, India) and laser fluorimeter (CAT, Indore, India) for the determination of uranium in natural waters

  13. Natural Radioactivity around Former Uranium Mine, Kalna in Eastern Serbia

    International Nuclear Information System (INIS)

    Bikit, I.; Bikit, K.; Forkapic, S.; Hansman, J.; Krmar, M.; Mrda, D.; Nikolov, J.; Todorovic, N.; Veskovic, M.; Kozmidis-Luburic, U.

    2013-01-01

    'Grabovnica' near small village Kalna was one of the first uranium mine established in Yugoslavia. In 1963, the Nuclear Energy Commission began operating the mine and mill. Between 1964 and 1966, the staff at this mine extracted and produced an estimated 900 kg of UO2 and 400 kg of uranium metal. The Kalna ore was of poor quality, containing very low uranium content, which required higher-cost mining and refining methods. That was the main reason for closing this mine. This paper presents results obtained by measuring the activity concentration of soil and water samples by gamma spectrometry and also indoor 222Rn activity concentrations in houses in the nearby village Kalna. The investigations of radioactivity content of the samples collected around abandoned mine 'Grabovnica' are carried out in order to determine the present state of the environment in this area. Most of the examined samples show elevated radioactivity. Only six samples (from 14 measured by gamma-spectroscopy) have external hazard index less than one. There are two soil samples taken from the entrance to the main shaft which have really high external hazard index. The obtained results also show higher activity concentration of 137Cs in some samples. The highest activity concentration of 222Rn is found in one house which is working area. All houses are very well ventilated which greatly affect 222Rn activity concentrations in air, so there is no need for any intervention. The mine was never officially decommissioned. The results obtained might be useful for the future decommissioning procedure. Future investigations should include other mentioned former mine locations in East Serbia and also comparison with areas of this origin worldwide.(author)

  14. Trialed production of low protein irradiated natural rubber latex in factory scale by gamma irradiation technique

    International Nuclear Information System (INIS)

    Utama, Marga; Herwinarni, S.; Halik, H.M.; Siswanto; Suharyanto; Syamsu, Y.; Handoko, B.

    2006-01-01

    Four tons fresh field natural rubber latex (FNRL) with total solid content 30% were added with 2 phr (part hundred ratio of rubber) normal butyl acrylate (nBA) then irradiated by gamma rays at 25 kGy. The irradiated FNRL was centrifuged, then the properties of irradiated centrifuged natural rubber latex (INRL) and its film were measured before and after storage for 5 months. It is found that the INRL is stable latex during storage in 5 months, with lowest protein, and free nitrosamine content. The tensile strength of INRL film was 24-27 MPa, and modulus 600% was 1,5-2,0 MPa, elongation at break was 900%, and hardness was 27-29 Shore A, while the extractable protein content less than 100 μg/g. (author)

  15. Measure of uranium enrichment by 14 MeV neutron irradiation

    International Nuclear Information System (INIS)

    Rezende, H.R.

    1987-01-01

    A non-destructive technique for the determination of uranium in UO 2 samples was developed, marking use of the change in the fission cross of a nuclide with the neutron energy. The active interrogation method was used by irradiating the samples with pulsed 14 MeV neutrons and furtherdetection of delayed fission neutrons. In order to descriminated U-238 from U-235 the neutron energy was tailored by means of two concentric cylinders of lead and paraffin/poliethylene, 11 and 4 cm thick. Between neutron pulses, delayed neutrons from fission were detected by a long counter built with five BF 3 proportional counters. Calibration curves for enrichment and total mass versus delayed neutron response were obtained using available UO 2 pellets of Known enrichment. Enrichment detection limit, obtained with 95% confidence level by the the Student distribution was estimated to be 0.33%. The minimal detectable mass was estimated to be 4.4 g. (Author) [pt

  16. Measurement of uranium enrichment by 14 MeV neutron irradiation

    International Nuclear Information System (INIS)

    Rezende, H.R.

    1987-01-01

    a non-destructive technique for the determination of uranium in UO 2 samples was developed, making use of the change in the fission cross section of a nuclide with the neutron energy. The active interrogation method was used by irradiating the samples with pulsed 14 MeV neutrons and further detection of delayed fission neutrons. In order to discriminate U-238 from U-235 the neutron energy was tailored by means of two concentric cylinders of lead and paraffin/poliethylene, 11 and 4 cm thick. Between neutron pulses, delayed neutrons from fission were detected by a long counter built with five BF 3 proportional counters. Calibration curves for enrichment and total mass versus delayed neutron response were obtained using available UO 2 pellets of known enrichment. Enrichment detection limit, obtained with 95% confidence level by the Student distribution was estimated to be 0.33%. The minimal detectable mass was estimated to be 4.4 g. (author) [pt

  17. Separation and purification of short lived fission products from irradiated uranium

    International Nuclear Information System (INIS)

    Balasubramanian, K.R.; Rao, K.L.N.; Mathai, C.; Varma, R.N.; Dhiwar, V.I.; Saxena, S.K.

    1991-01-01

    Fission produced radioisotopes like 95 Zr, 140 Ba, 103 Ru, 89 Sr and 91 Y whose half lives are less than 1 year find a wide variety of applications in the fields of industry, medicine and research. Isotope Division, BARC has been supplying these isotopes in hudreds of mCi amounts during the past several years. A new method for the sequential separation of these isotopes from irradiated uranium has been developed based on synthetic inorganic exchangers like stannic phosphate, polyphospho antimonic acid, hydrous manganese dioxide, etc. This report describes the new flow sheet worked out and adopted for the regular processing of these isotopes at hundreds of milli curie amounts. (author). 19 refs., 4 tabs. , 1 fig

  18. Preparation of vinyl acetate grafted natural rubber by irradiation method

    Energy Technology Data Exchange (ETDEWEB)

    Porntrairat, A.; Pattamaprom, C. [Center of Excellence on Natural Rubber Technology, Department of Chemical Engineering, Faculty of Engineering, Thammasat University, Pathumthani 12120 (Thailand)

    2016-03-09

    Improvement in properties of natural rubber could be done by several methods. In this research, gamma radiation technique, which is simple, accurate, easy to control and clean, was applied to enhance the properties of natural rubber (NR) in latex state. The purpose of this research is to study the appropriate condition for preparing grafted natural rubber latex by using irradiation method. Vinyl acetate monomers (VAc) were grafted onto natural rubber latex (NR-g-PVAc) at 0-10 kGys by gamma radiation from Cobalt-60 source at room temperature. Physical properties of grafted natural rubber such as chloroform number, swelling ratio and gel content were measured. The VAc content of NR-g-PVAc was investigated by titration and visualized by FTIR spectroscopy. The FTIR spectra of NR-g-PVAc prepared at 0-10 kGys showed characteristic peaks of the vinyl acetate confirming that VAc could be grafted onto natural rubber molecular chains effectively under appropriate irradiation conditions. From the result, radiation grafting was found to be a useful technique for grafting of vinyl acetate onto natural rubber.

  19. Smectite-zeolite envelope surrounding the Tsukiyoshi uranium deposit, central Japan. A natural analogue study

    International Nuclear Information System (INIS)

    Utada, Minoru

    2003-01-01

    The Tsukiyoshi uranium deposit in Gifu Prefecture is the largest one in Japan. It is embedded in lower part of the Mizunami Group of Miocene age. Relating to the existence of this uranium deposit, the constituent minerals in sediments were studied by XRD and SEM, using many drilling cores. The most abundant authigenic mineral is smectite. The amount of smectite increases generally from upper to lower horizons, and a highly smectitized zone is situated around the uranium deposit. Smectitization predominated in mafic glassy grains of sediments, which was probably formed in early burial diagenesis. Zeolites including clinoptilolite-heulandite, mordenite, analcime, chabazite and philipsite are secondly abundant authigenic minerals. They seem to have been formed at early to late diagenetic stages. Opaline silica is rather rare. Carbonate minerals, including calcite, dolomite, siderite and rhodocrosite are common. They may be formed by diagenesis as well. Gypsum and pyrite occur in upper horizons and lower horizons, respectively. In particular, a highly smectitized zone including pyrite probably played an important role for retarding the migration of uranium and as a result keeping the uranium deposit for past one million years. This smectite-zeolite envelope surrounding the Tsukiyoshi uranium deposit is regarded as a natural analogue of the buffer materials surrounding the high-level radioactive waste repository. (author)

  20. 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

  1. Uranium

    International Nuclear Information System (INIS)

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

    1981-01-01

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

  2. Natural uranium/conversion services/enrichment services

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    This article is the 1993 uranium market summary. During this reporting period, there were 50 deals in the concentrates market, 26 deals in the UF6 market, and 14 deals for enrichment services. In the concentrates market, the restricted value closed $0.15 higher at $9.85, and the unrestricted value closed down $0.65 at $7.00. In the UF6 market, restricted prices fluctuated and closed higher at $31.00, and unrestricted prices closed at their initial value of $24.75. The restricted transaction value closed at $10.25 and the unrestricted value closed at $7.15. In the enrichment services market, the restricted value moved steadily higher to close at $84.00 per SWU, and the unrestricted value closed at its initial value of $68.00 per SWU

  3. Linearity assumption in soil-to-plant transfer factors of natural uranium and radium in Helianthus annuus L

    International Nuclear Information System (INIS)

    Rodriguez, P. Blanco; Tome, F. Vera; Fernandez, M. Perez; Lozano, J.C.

    2006-01-01

    The linearity assumption of the validation of soil-to-plant transfer factors of natural uranium and 226 Ra was tested using Helianthus annuus L. (sunflower) grown in a hydroponic medium. Transfer of natural uranium and 226 Ra was tested in both the aerial fraction of plants and in the overall seedlings (roots and shoots). The results show that the linearity assumption can be considered valid in the hydroponic growth of sunflowers for the radionuclides studied. The ability of sunflowers to translocate uranium and 226 Ra was also investigated, as well as the feasibility of using sunflower plants to remove uranium and radium from contaminated water, and by extension, their potential for phytoextraction. In this sense, the removal percentages obtained for natural uranium and 226 Ra were 24% and 42%, respectively. Practically all the uranium is accumulated in the roots. However, 86% of the 226 Ra activity concentration in roots was translocated to the aerial part

  4. Linearity assumption in soil-to-plant transfer factors of natural uranium and radium in Helianthus annuus L

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, P. Blanco [Departamento de Fisica, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz (Spain); Tome, F. Vera [Departamento de Fisica, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz (Spain)]. E-mail: fvt@unex.es; Fernandez, M. Perez [Area de Ecologia, Departamento de Fisica, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz (Spain); Lozano, J.C. [Laboratorio de Radiactividad Ambiental, Facultad de Ciencias, Universidad de Salamanca, 37008 Salamanca (Spain)

    2006-05-15

    The linearity assumption of the validation of soil-to-plant transfer factors of natural uranium and {sup 226}Ra was tested using Helianthus annuus L. (sunflower) grown in a hydroponic medium. Transfer of natural uranium and {sup 226}Ra was tested in both the aerial fraction of plants and in the overall seedlings (roots and shoots). The results show that the linearity assumption can be considered valid in the hydroponic growth of sunflowers for the radionuclides studied. The ability of sunflowers to translocate uranium and {sup 226}Ra was also investigated, as well as the feasibility of using sunflower plants to remove uranium and radium from contaminated water, and by extension, their potential for phytoextraction. In this sense, the removal percentages obtained for natural uranium and {sup 226}Ra were 24% and 42%, respectively. Practically all the uranium is accumulated in the roots. However, 86% of the {sup 226}Ra activity concentration in roots was translocated to the aerial part.

  5. Natural radionuclides in effluents release by a deactivated uranium mine

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Wagner S.; Kelecom, Alphonse; Silva, Ademir X.; Lopes, José M.; Pinto, Carlos E.C.; Py Júnior, Delcy A.; Antunes, Marcos M., E-mail: pereiraws@gmail.com, E-mail: caerjbr@gmail.com, E-mail: wspereira@inb.gov.br, E-mail: delcy@inb.gov.br, E-mail: Antunes@inb.gov.br, E-mail: lararapls@hotmail.com, E-mail: Ademir@nuclear.ufrj.br, E-mail: marqueslopes@yahoo.com.br [Universidade Veiga de Almeida (UVA), Rio de Janeiro, RJ (Brazil); Indústrias Nucleares do Brasil (COMAP.N/FCN/INB), Resende RJ (Brazil). Fábrica de Combustível Nuclear. Coordenação de Meio Ambiente e Proteção Radiológica Ambiental; Universidade Federal Fluminense (LARARA-PLS/UFF), Niterói, RJ (Brazil). Laboratório de Radiobiologia e Radiometria; Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear

    2017-07-01

    The Ore Treatment Unit (OTU) is a mine and deactivated uranium plant in the city of Caldas, Minas Gerais, Brazil. This facility possesses three points of release of liquid effluents containing radionuclides: point 014, 025 and 076. At these points, the values of activity concentrations (AC) of the radionuclides U{sub nat}, {sup 226}Ra, {sup 210}Pb, {sup 232}Th and {sup 228}Ra were analyzed in 2012. The evaluation of point 014 by univariate statistics pointed four groups. [U{sub nat} > {sup 228}Ra > ({sup 226}Ra = {sup 210}Pb) >{sup 232}Th]. The multivariate statistics separated the radionuclides into two groups: [(U{sub nat} and {sup 232}Th) and ({sup 226}Ra, {sup 228}Ra and {sup 210}Pb)]. At point 025, the univariate statistics described three groups: [Un{sub at} > ({sup 228}Ra = {sup 210}Pb) > ({sup 226}Ra = {sup 232}Th)] and the multivariate analysis also described three but different groups: [(U{sub nat} and {sup 228}Ra), ({sup 226}Ra and {sup 210}Pb) and {sup 232}Th]. In turn, point 076 showed another behavior. The univariate analysis showed only two groups: [(U{sub nat}) > ({sup 226}Ra, {sup 228}Ra, {sup 210}Pb, {sup 232}Th)]. Differently, the multivariate statistics defined three groups: [(U{sub nat} and {sup 232}Th), ({sup 226}Ra and {sup 228}Ra) and {sup 210}Pb].Thus, statistical analysis showed that each point has releases of effluents with different characteristics. Both the behaviors of releases, based on multivariate statistics, and of the AC magnitudes, based on the univariate statistics, are different between the points. The only common features were the greater magnitude of uranium and the smaller magnitude of thorium. (author)

  6. Protactinium-231 found in natural thorium irradiated in JMTR

    International Nuclear Information System (INIS)

    Suzuki, Susumu; Mitsugashira, Toshiaki; Hara, Mitsuo; Satoh, Isamu; Shiokawa, Yoshinobu; Satoh, Michiko

    1987-01-01

    Natural thorium dioxides, which differed in the content of 230 Th, were irradiated in JMTR(Japan Material Testing Reactor). 232 U, 233 U, 231 Pa, 233 Pa, and remaining Th were measured radiometrically. High production of 231 Pa and high consumption of 230 Th were observed and it was necessary to assume large resonance capture of 230 Th in order to explain the production of 231 Pa and the consumption of 230 Th. (author)

  7. Radiation protection program applied to occupationally exposed individuals at the IPEN/CNEN-SP pilot plant in the 1980s for natural uranium compounds

    International Nuclear Information System (INIS)

    Silva, Teresinha de Moraes da; Sordi, Gian Maria A.A.; Vasques, Francisco Mário Feijó

    2017-01-01

    The work evidences the chemical processing of natural uranium from the yellowcake phase to the production of UF 6 natural uranium hexafluoride, a process carried out at the IPEN/CNEN-SP pilot plant. Radiation protection management was intended to monitor occupationally exposed individuals - IOEs, the workplace and the environment. An individual monitoring program for IOEs was developed for both external irradiation and incorporation of radioactive material. The IOEs were monitored externally with film-type dosimeters and the in vitro method was applied internally for urine analysis. For the workplace the monitoring program for equipment and floors was developed, determining the exposure rate from the process equipment, surface contamination expressed in Bq.cm -2 in equipment and floors, complemented by the air monitoring program both for the worker as well as for the workplace. Cellulose filters with aerodynamic diameter of 0.3 micron to 8.0 micron were used

  8. Test calculations of photoneutrons emission from surface of uranium sphere irradiated by 28 MeV electrons

    International Nuclear Information System (INIS)

    Blokhin, A.I.; Degtyarev, I.I.

    2002-01-01

    In this paper the results of physical verification for the BOFOD photonuclear data files are reported, available for the uranium isotopes U 235 , U 238 . These results were compared with calculated data by the parameterization driven model of photonuclear reaction and experimental data. Experimental data of photoneutron yields from surface of uranium sphere irradiated by 28 MeV electrons are used for a verification. Both calculations have been carried out with the RTS and T general purpose Monte Carlo code with detailed electron-photon-nucleon transport simulation using the ENDF/B-VI and EPDL evaluated data libraries

  9. Simultaneous determination of uranium and plutonium in dissolver solution of irradiated fuel, using ID-TIMS. IRP-11

    International Nuclear Information System (INIS)

    Shah, Raju; Sasi Bhushan, K.; Govindan, R.; Alamelu, D.; Khodade, P.S.; Aggarwal, S.K.

    2007-01-01

    A simple sample preparation and simultaneous analysis method to determine uranium and plutonium from dissolver solution, employing the technique of Isotope Dilution Mass spectrometry has been demonstrated. The method used, co-elusion of Uranium and Plutonium from anion exchanger column after initial elution of major part of uranium in 1:5 HNO 3 in order to reduce the initial U/Pu ratio from 1000 to about 100-200 in the co-eluted fraction. Due to the availability of variable multi-collector system, different Faraday cups were adjusted to collect the different ion intensities corresponding to the different masses, during the simultaneous analysis of Uranium and Plutonium, loaded on Re double filament assembly. 233 U and PR grade Plutonium were used as spikes to determine Uranium and Plutonium from dissolver solution of irradiated fuel from research reactor. The possibility of getting the isotopic composition of uranium from the simultaneous analysis of co-eluted purified fraction of U and Pu from spiked aliquots is also explained. (author)

  10. Natural uranium and 226Ra in bottled potable waters of Argentina

    International Nuclear Information System (INIS)

    Bomben, Ana M.; Palacios, Miguel A.

    2001-01-01

    This paper presents the results obtained of the measurement of the natural uranium and 226 Ra concentrations carried out on 345 drinking water samples coming from different provinces of Argentina. The samples were collected from tap water systems and private wells. Six bottled mineral waters samples, selected from those most extensively consumed, were also analyzed. The natural uranium concentration was determined by a fluorimetric procedure and 226 Ra by the 222 Rn emanation technique and liquid scintillation counting. Values ranging from 0,03 to 50 μg L -1 of natural uranium and concentrations up to 22 mBq L -1 were found in the drinking water samples analyzed. Natural uranium concentrations from 0,04 to 3,8 μg L -1 and 226 Ra concentrations up to 2,4 mBq L -1 were measured in the bottled mineral waters samples. Based on the water intake rate and the measured concentrations of both radionuclides analyzed, an annual collective effective dose of 1,5 man Sv and an average committed effective dose of 0,5 μSv a -1 , were calculated for the City of Buenos Aires inhabitants. (author)

  11. Radon 226 and natural Uranium in potable waters to the Argentina Republic

    International Nuclear Information System (INIS)

    Bomben, A.M.; Palacios, M.A.

    1998-01-01

    157 samples were analyzed in the Buenos Aires City. Gathered in the domiciliary distribution net and private wells. The radon 226 concentration to determines for the radon 226 emanation technique and liquid scintilligraphy. The natural uranium concentration one carries out for fluorimetric methods

  12. Alpha low activity determination from limitter isotopes of uranium, thorium ands radium in natural waters

    International Nuclear Information System (INIS)

    Gascon, J.L.; Crespo, M.T.; Acena, M.L.

    1989-01-01

    A method to concentrate uranium, thorium and radium in natural waters has been developed. The method, based on the adsorbing propert-ies of manganes dioxide, has been applied to determine the alpha emitter isotopes of these elements in drinking water of Madrid. In this work we present the description of the method, the analytical procedu-res and the obtained results. (Author)

  13. Data base for a CANDU-PHW operating on a once-through natural uranium cycle

    International Nuclear Information System (INIS)

    1979-07-01

    This report, prepared for INFCE, describes a standard 600 MW(e) CANDU-PHW reactor operating on a once-through natural uranium fuel cycle. Subsequently, data are given for an extrapolated 1000 MW(e) design (the nominal capacity adopted for the INFCE study) operating on the same fuel cycle. (author)

  14. Calculations on heavy-water moderated and cooled natural uranium fuelled power reactors

    International Nuclear Information System (INIS)

    Pinedo V, J.L.

    1979-01-01

    One of the codes that the Instituto Nacional de Investigaciones Nucleares (Mexico) has for the nuclear reactors design calculations is the LEOPARD code. This work studies the reliability of this code in reactors design calculations which component materials are the same of the heavy water moderated and cooled, natural uranium fuelled power reactors. (author)

  15. Monte Carlo calculation of received dose from ingestion and inhalation of natural uranium

    International Nuclear Information System (INIS)

    Trobok, M.; Zupunski, Lj.; Spasic-Jokic, V.; Gordanic, V.; Sovilj, P.

    2009-01-01

    For the purpose of this study eighty samples are taken from the area Bela Crkva and Vrsac. The activity of radionuclide in the soil is determined by gamma- ray spectrometry. Monte Carlo method is used to calculate effective dose received by population resulting from the inhalation and ingestion of natural uranium. The estimated doses were compared with the legally prescribed levels. (author) [sr

  16. Uranium

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

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

  17. Uranium

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

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

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

    Science.gov (United States)

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

    1973-01-01

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

  19. ELECTROCHEMICAL STUDIES OF URANIUM METAL CORROSION MECHANISM AND KINETICS IN WATER

    International Nuclear Information System (INIS)

    Boudanova, Natalya; Maslennikov, Alexander; Peretroukhine, Vladimir F.; Delegard, Calvin H.

    2006-01-01

    During long-term underwater storage of low burn-up uranium metal fuel, a corrosion product sludge forms containing uranium metal grains, uranium dioxide, uranates and, in some cases, uranium peroxide. Literature data on the corrosion of non-irradiated uranium metal and its alloys do not allow unequivocal prediction of the paragenesis of irradiated uranium in water. The goal of the present work conducted under the program 'CORROSION OF IRRADIATED URANIUM ALLOYS FUEL IN WATER' is to study the corrosion of uranium and uranium alloys and the paragenesis of the corrosion products during long-term underwater storage of uranium alloy fuel irradiated at the Hanford Site. The elucidation of the physico-chemical nature of the corrosion of irradiated uranium alloys in comparison with non-irradiated uranium metal and its alloys is one of the most important aspects of this work. Electrochemical methods are being used to study uranium metal corrosion mechanism and kinetics. The present part of work aims to examine and revise, where appropriate, the understanding of uranium metal corrosion mechanism and kinetics in water

  20. Natural radionuclides in effluents release by a deactivated uranium mine

    International Nuclear Information System (INIS)

    Pereira, Wagner S.; Kelecom, Alphonse; Silva, Ademir X.; Lopes, José M.; Pinto, Carlos E.C.; Py Júnior, Delcy A.; Antunes, Marcos M.; Indústrias Nucleares do Brasil; Universidade Federal Fluminense; Coordenacao de Pos-Graduacao e Pesquisa de Engenharia

    2017-01-01

    The Ore Treatment Unit (OTU) is a mine and deactivated uranium plant in the city of Caldas, Minas Gerais, Brazil. This facility possesses three points of release of liquid effluents containing radionuclides: point 014, 025 and 076. At these points, the values of activity concentrations (AC) of the radionuclides U_n_a_t, "2"2"6Ra, "2"1"0Pb, "2"3"2Th and "2"2"8Ra were analyzed in 2012. The evaluation of point 014 by univariate statistics pointed four groups. [U_n_a_t > "2"2"8Ra > ("2"2"6Ra = "2"1"0Pb) >"2"3"2Th]. The multivariate statistics separated the radionuclides into two groups: [(U_n_a_t and "2"3"2Th) and ("2"2"6Ra, "2"2"8Ra and "2"1"0Pb)]. At point 025, the univariate statistics described three groups: [Un_a_t > ("2"2"8Ra = "2"1"0Pb) > ("2"2"6Ra = "2"3"2Th)] and the multivariate analysis also described three but different groups: [(U_n_a_t and "2"2"8Ra), ("2"2"6Ra and "2"1"0Pb) and "2"3"2Th]. In turn, point 076 showed another behavior. The univariate analysis showed only two groups: [(U_n_a_t) > ("2"2"6Ra, "2"2"8Ra, "2"1"0Pb, "2"3"2Th)]. Differently, the multivariate statistics defined three groups: [(U_n_a_t and "2"3"2Th), ("2"2"6Ra and "2"2"8Ra) and "2"1"0Pb].Thus, statistical analysis showed that each point has releases of effluents with different characteristics. Both the behaviors of releases, based on multivariate statistics, and of the AC magnitudes, based on the univariate statistics, are different between the points. The only common features were the greater magnitude of uranium and the smaller magnitude of thorium. (author)

  1. Natural uranium equivalent fuel. An innovative design for proven CANDU technology

    Energy Technology Data Exchange (ETDEWEB)

    Pineiro, F.; Ho, K.; Khaial, A.; Boubcher, M.; Cottrell, C.; Kuran, S. [Candu Energy Inc., Mississauga, Ontario (Canada); Zhenhua, Z.; Zhiliang, M. [Third Qinshan Nuclear Power Co., Haiyan, Zhejiang (China)

    2015-09-15

    The high neutron economy, on-power refuelling capability and fuel bundle design simplicity in CANDU® reactors allow for the efficient utilization of alternative fuels. Candu Energy Inc. (Candu), in collaboration with the Third Qinshan Nuclear Power Company (TQNPC), the China North Nuclear Fuel Corporation (CNNFC), and the Nuclear Power Institute of China (NPIC), has successfully developed an advanced fuel called Natural Uranium Equivalent (NUE). This innovative design consists of a mixture of recycled and depleted uranium, which can be implemented in existing CANDU stations thereby bringing waste products back into the energy stream, increasing fuel resources diversity and reducing fuel costs. (author)

  2. Natural uranium equivalent fuel an innovative design for proven CANDU technology

    Energy Technology Data Exchange (ETDEWEB)

    Pineiro, F.; Ho, K.; Khaial, A.; Boubcher, M.; Cottrell, C.; Kuran, S., E-mail: fabricia.pineiro@candu.com [Candu Energy Inc., Mississauga, ON (Canada); Zhenhua, Z.; Zhiliang, M. [Third Qinshan Nuclear Power Company, Haiyan, Zhejiang (China)

    2015-07-01

    The high neutron economy, on-power refuelling capability and fuel bundle design simplicity in CANDU reactors allow for the efficient utilization of alternative fuels. Candu Energy Inc. (Candu), in collaboration with the Third Qinshan Nuclear Power Company (TQNPC), the China North Nuclear Fuel Corporation (CNNFC), and the Nuclear Power Institute of China (NPIC), has successfully developed an advanced fuel called Natural Uranium Equivalent (NUE). This innovative design consists of a mixture of recycled and depleted uranium, which can be implemented in existing CANDU stations thereby bringing waste products back into the energy stream, increasing fuel resources diversity and reducing fuel costs. (author)

  3. Geochemical behaviour of natural uranium-series nuclides in geological formation

    International Nuclear Information System (INIS)

    Yamakawa, Minoru

    1991-01-01

    Recent research and investigation show that the Tono uranium deposit and its natural uranium-series nuclides have been preserved, without any significant changes like re-migration or reconcentration, throughout geological events such as upheaval-submergence, marine transgression-regression, and faulting which can readily change geological, hydrogeological, and geochemical conditions. This situation might have come about as a result of being kept in a geometrical closure system, with reducing and milk alkalic geochemical conditions, from the hydrogeological and geochemical point of view. (author)

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

    International Nuclear Information System (INIS)

    Loefgren, A.; Kautsky, U.

    2009-01-01

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

  5. Geochemical behaviour of uranium in sedimentary formations: insights from a natural analogue study - 16340

    International Nuclear Information System (INIS)

    Noseck, Ulrich; Brasser, Thomas; Havlova, Vaclava; Cervinka, Radek; Suksi, Juhani

    2009-01-01

    Groundwater data from the natural analogue site Ruprechtov have been evaluated with special emphasis on the uranium behaviour in the so-called uranium-rich clay/lignite horizon. In this horizon in-situ Eh-values in the range of -160 to -280 mV seem to be determined by the SO 4 2- /HS - couple. Under these conditions U(IV) is expected to be the preferential redox state in solution. However, on-site measurements in groundwater from the clay/lignite horizon show only a fraction of about 20 % occurring in the reduced state U(IV). Thermodynamic calculations reveal that the high CO 2 partial pressure in the clay/lignite horizon can stabilise hexavalent uranium, which explains the occurrence of U(VI). The calculations also indicate that the low uranium concentrations in the range between 0.2 and 2.1 μg/l are controlled by amorphous UO 2 and/or the U(IV) phosphate mineral ningyoite. This confirms the findings from previous work that the uranium (IV) mineral phases are long-term stable under the reducing conditions in the clay/lignite horizon without any signatures for uranium mobilisation. It supports the current knowledge of the geological development of the site and is also another important indication for the long-term stability of the sedimentary system itself, namely of the reducing geochemical conditions in the near-surface (30 m to 60 m deep) clay/lignite horizon. Further work with respect to the impact of changes in redox conditions on the uranium speciation is on the way. (authors)

  6. Spontaneous ignition of natural uranium in Tokai Research Establishment, Japan Atomic Energy Research Institute

    International Nuclear Information System (INIS)

    1989-01-01

    At P.M. 7:23, May 30, 1989, a fire alarm functioned in the uranium enrichment laboratory building, and immediately investigation was carried out, as the result, smoke was confirmed in the nuclear fuel storage. In the nuclear fuel storage, there were five plastic bottles containing natural uranium chips, and smoke arose from three of them. Immediately fire fighting was carried out with powder extinguishers and others, the uranium chips which were regarded as the heat generating source were moved into stainless steel cans, and air was cut off with extinguishing sand, as the result, around P.M. 9:50, heat generation ceased. At present the detailed cause is being investigated, but it is considered that the uranium chips contained in plastic bottles reacted with air by some cause, and generated heat in the form of spontaneous ignition, as the result, the plastic bottles and the vinyl sheets placed under them smoked. The stack dust monitor in the uranium enrichment laboratory building showed the normal value, and there was not the effect to surrounding environment. The workers who did fire fighting with whole face masks were not affected by smoke. (K.I.)

  7. Radioactivity of uranium production cycle facilities in the Czech Republic compared to the natural environment

    International Nuclear Information System (INIS)

    Matolin, M.

    2002-01-01

    Forty-five years (1946-1990) of intensive uranium exploration and exploitation in the Czech Republic led to mining at 64 uranium deposits. These mining and milling activities left numerous accumulations of waste rock material in the landscape. The radioactivity of these man-made accumulations was measured and compared to the natural radiation environment. Waste rock dumps at the uranium deposits Pribram, Rozna, Jachymov, Straz-Hamr and deposits in the Zelezne Hory area show surface gamma dose rates mostly in the range of 200-1000 nGy/h, with a uranium concentration 10-100 ppm eU. An extremely high radioactivity of 3000-4200 nGy/h was detected at the extensive uranium processing tailings impoundments at Straz. Terrestrial gamma dose rate of regional geological units in the Czech Republic is in the range of 6-245 nGy/h. Reclamation and recultivation of dumps, control of their radioactivity and restriction of their accessibility are the major measures introduced to protect the public. (author)

  8. Rapid determination of uranium in natural waters by fthermal emission mass spectrometry

    International Nuclear Information System (INIS)

    Ferguson, J.R.; Caylor, J.D.; Rogers, E.R.; Cole, S.H.

    1977-03-01

    A method has been developed to rapidly analyze natural water samples for part-per-trillion (ng/l) concentrations of uranium using a custom-built thermal-emission mass spectrometer. The filtered water sample is spiked with 233 U as an internal standard and extracted with a 2 percent solution of TOPO (trioctylphosphine oxide) in carbon tetrachloride. An aliquot of the organic phase is evaporated and the uranium in the residue extracted with aqueous ammonium carbonate. A 5j-μl aliquot is taken and dried on a flat uranium concentration of 3 ng/l will yield a count rate greater than three times the standard deviation, plus the mean of the background, and is defined as the lowest determinable concentration. The standard deviation of the method is 3 percent at accuracy of the method has been evaluated by comparing the results with a fluorescence procedure. There is very good agreement for water samples with uranium concentrations from 200 to 1000 ng/l. The mass spectrometer is a 6-in. -radius, 60-degree-sector instrument equipped for ion counting and having a vacuum system allowing rapid sample changing while maintaining a high source vacuum. A multiplexer and high-voltage s witch provide synchronized peak switching and scaler gating for monitoring three isotopes of uranium 238, 235, and 233. With this instrument, an analyst can achieve an analysis rate in excess of 50 samples per eight-hour shift

  9. Natural and depleted uranium in the topsoil of Qatar: Is it something to worry about?

    International Nuclear Information System (INIS)

    Shomar, Basem; Amr, Mohamed; Al-Saad, Khalid; Mohieldeen, Yasir

    2013-01-01

    Highlights: • Scientific studies on Uranium in the arid environment are almost absent. • Qatar is closed to Iraq and Iran where the two countries were exposed to long wars. • The paper introduces baseline study integrates chemistry, instrumentation and GIS mapping. • The study opens new horizons for similar studies on the field using similar approach. - Abstract: This study examines uranium in soils of Qatar to investigate whether there is any detectable traces of depleted uranium (DU). 409 soil samples were collected using a 10 km grid system throughout the State of Qatar. The U concentrations and isotopic compositions ( 235 U/ 238 U) were determined using an ICP-MS. The U concentrations range from 0.05 to 4.7 mg/kg and the 235 U/ 238 U isotopic signatures are in the range 0.007–0.008, i.e. comparable to the isotopic ratio in natural uranium (NU). The distribution of these concentrations in the topsoil were used to see correlations with locations of pollution point sources and environmentally hot areas associated with human activity: industrial estates, solid waste dumping sites, wastewater treatment plants, sea harbors, airports, and public transport network. New thematic maps were built using Geographic Information System (GIS) software. The results showed that there is no linkage between the occurrence, distribution, concentrations and isotopic ratios of U and these hotspots. More importantly, due to the low concentration of organic matter (OM) in soils of Qatar, very limited P-fertilization, the alkaline nature of soil (pH 8) and low Fe/Mn contents make soil uranium concentrations very low. The residential areas, including the capital Doha, had the lowest total concentrations of uranium and isotopic ratios of the country while the northern and western parts showed the highest values

  10. 75 years ago. The discovery of nuclear fission during the neutron irradiation of uranium on 17 December 1938 in Berlin

    International Nuclear Information System (INIS)

    Kuczera, Bernhard

    2013-01-01

    A ground-breaking, scientific discovery made in the Berlin experiments of the year 1938 on neutron irradiation of uranium, was that atom nuclei can be fissured and, during the fission energy, so-called nuclear energy, is released. If further U-235 atoms are in the immediate vicinity, the released neutrons can trigger a chain reaction of the nuclear fission. The story of this ground-breaking discovery that led to the worldwide civil utilisation of nuclear energy is outlined here. The discovery of neutrons and their implementation in radiation experiments occurred in the 1930s. The research work followed the model of the Stockholm citizen Niels Bohr on the configuration of an atom. In 1930, Walther Bothe reported on the occurrence of a high-energy radiation when beryllium was irradiated with alpha-particles. James Chadwick could prove experimentally in 1932 that this is a current of high-energy, electrically neutral particles. He called these particles neutrons. In Berlin, the radio-chemist Otto Hahn is the Director at the Kaiser-Wilhelm-Institute for Chemistry and head of the chemical-radioactive department. In the years 1935 to 1938, the radiation experiments of uranium with neutrons were at the centre of the research in Berlin. In October 1938, Hahn and Strassmann responded with their own experiments to the scientific challenge of Irene Curie and Paul Savitch of 3.5-hours of activity when uranium was radiated with neutrons. The decisive discovery for the neutron radiation of uranium was made by Hahn and Strassmann on 17 December 1938. From the results of different experiments, they conclude: 'Our radium isotopes have the properties of barium.' On 19 December, Hahn informs Lise Meitner and speaking on the issue of 'Where does the barium come from?' addresses a possible 'bursting' of the uranium nucleus. That is Hahn's 'Heureka.' moment: He recognises that the neutron radiation does not only effect radiochemical transformations, but can also cause the uranium

  11. Irradiation performance of uranium-molybdenum alloy dispersion fuels; Desempenho sob irradiacao de elementos combustiveis do tipo U-Mo

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Cirila Tacconi de

    2005-07-01

    The U-Mo-Al dispersion fuels of Material Test Reactors (MTR) are analyzed in terms of their irradiation performance. The irradiation performance aspects are associated to the neutronic and thermal hydraulics aspects to propose a new core configuration to the IEA-R1 reactor of IPEN-CNEN/SP using U-Mo-Al fuels. Core configurations using U-10Mo-Al fuels with uranium densities variable from 3 to 8 gU/cm{sup 3} were analyzed with the computational programs Citation and MTRCR-IEA R1. Core configurations for fuels with uranium densities variable from 3 to 5 gU/cm{sup 3} showed to be adequate to use in IEA-R1 reactor e should present a stable in reactor performance even at high burn-up. (author)

  12. Is uranium dioxide a glass at high temperature: the reason for its irradiation resistance?

    International Nuclear Information System (INIS)

    Desgranges, Lionel

    2008-01-01

    Electronic intrinsic carriers are shown to have some influence on UO 2 high temperature properties. The physical nature of these carriers, called polarons, is discussed and it is proposed that they could correspond to quasi-broken bonds, in a similar way to intrinsic electronic defects in SiO 2 . It is shown that this hypothesis provides an explanation, at least qualitative, for UO 2 specific behavior at high temperature and under irradiation. (author)

  13. EPR study of the production of OH radicals in aqueous solutions of uranium irradiated by ultraviolet light

    Directory of Open Access Journals (Sweden)

    MARKO DAKOVIĆ

    2009-06-01

    Full Text Available The aim of the study was to establish whether hydroxyl radicals (•OH were produced in UV-irradiated aqueous solutions of uranyl salts. The production of •OH was studied in uranyl acetate and nitrate solutions by an EPR spin trap method over a wide pH range, with variation of the uranium concentrations. The production of •OH in uranyl solutions irradiated with UV was unequivocally demonstrated for the first time using the EPR spin-trapping method. The production of •OH can be connected to speciation of uranium species in aqueous solutions, showing a complex dependence on the solution pH. When compared with the results of radiative de-excitation of excited uranyl (*UO22+ by the quenching of its fluorescence, the present results indicate that the generation of hydroxyl radicals plays a major role in the fluorescence decay of *UO22+. The role of the presence of carbonates and counter ions pertinent to environmental conditions in biological systems on the production of hydroxyl radicals was also assessed in an attempt to reveal the mechanism of *UO22+ de-excitation. Various mechanisms, including •OH production, are inferred but the main point is that the generation of •OH in uranium containing solutions must be considered when assessing uranium toxicity.

  14. Fabrication of uranium-plutonium mixed nitride fuel pins (88F-5A) for first irradiation test at JMTR

    International Nuclear Information System (INIS)

    Suzuki, Yasufumi; Iwai, Takashi; Arai, Yasuo; Sasayama, Tatsuo; Shiozawa, Ken-ichi; Ohmichi, Toshihiko; Handa, Muneo

    1990-07-01

    A couple of uranium-plutonium mixed nitride fuel pins was fabricated for the first irradiation tests at JMTR for the purpose of understanding the irradiation behavior and establishing the feasibility of nitride fuels as advanced FBR fuels. The one of the pins was fitted with thermocouples in order to observe the central fuel temperature. In this report, the fabrication procedure of the pins such as pin design, fuel pellet fabrication and characterizations, welding of fuel pins, and inspection of pins are described, together with the outline of the new TIG welder installed recently. (author)

  15. Metabolomics identifies a biological response to chronic low-dose natural uranium contamination in urine samples.

    Science.gov (United States)

    Grison, Stéphane; Favé, Gaëlle; Maillot, Matthieu; Manens, Line; Delissen, Olivia; Blanchardon, Eric; Banzet, Nathalie; Defoort, Catherine; Bott, Romain; Dublineau, Isabelle; Aigueperse, Jocelyne; Gourmelon, Patrick; Martin, Jean-Charles; Souidi, Maâmar

    2013-01-01

    Because uranium is a natural element present in the earth's crust, the population may be chronically exposed to low doses of it through drinking water. Additionally, the military and civil uses of uranium can also lead to environmental dispersion that can result in high or low doses of acute or chronic exposure. Recent experimental data suggest this might lead to relatively innocuous biological reactions. The aim of this study was to assess the biological changes in rats caused by ingestion of natural uranium in drinking water with a mean daily intake of 2.7 mg/kg for 9 months and to identify potential biomarkers related to such a contamination. Subsequently, we observed no pathology and standard clinical tests were unable to distinguish between treated and untreated animals. Conversely, LC-MS metabolomics identified urine as an appropriate biofluid for discriminating the experimental groups. Of the 1,376 features detected in urine, the most discriminant were metabolites involved in tryptophan, nicotinate, and nicotinamide metabolic pathways. In particular, N -methylnicotinamide, which was found at a level seven times higher in untreated than in contaminated rats, had the greatest discriminating power. These novel results establish a proof of principle for using metabolomics to address chronic low-dose uranium contamination. They open interesting perspectives for understanding the underlying biological mechanisms and designing a diagnostic test of exposure.

  16. The determination of minor isotope abundances in naturally occurring uranium materials. The tracing power of isotopic signatures for uranium

    Energy Technology Data Exchange (ETDEWEB)

    Ovaskainen, R

    1999-11-01

    The mass spectrometric determination of minor abundant isotopes, {sup 234}U and {sup 236}U in naturally occurring uranium materials requires instruments of high abundance sensitivity and the use of highly sensitive detection systems. In this study the thermal ionisation mass spectrometer Finnigan MAT 262RPQ was used. It was equipped with 6 Faraday cups and a Secondary Electron Multiplier (SEM), which was operated in pulse counting mode for the detection of extremely low ion currents. The dynamic measurement range was increased considerably combining these two different detectors. The instrument calibration was performed carefully. The linearity of each detector, the deadtime of the ion counting detector, the detector normalisation factor, the baseline of each detector and the mass discrimination in the ion source were checked and optimised. A measurement technique based on the combination of a Gas Source Mass Spectrometry (GSMS) and a Thermal Ionisation Mass Spectrometry (TIMS) was developed for the accurate determination of isotopic composition in naturally occurring uranium materials. Because the expected ratio of n({sup 234}U)/n({sup 238}U) exceeded the dynamic measurement range of the Faraday detectors of the TIMS instrument, an experimental design using a combination of two detectors was developed. The n({sup 234}U)/n({sup 235}U) and n({sup 236}U)/n({sup 235}U) ratios were determined using ion counting in combination with the decelerating device. The n({sup 235}U)/n({sup 238}U) ratio was determined by the Faraday detector. This experimental design allowed the detector cross calibration to be circumvented. Precisions of less than 1 percent for the n({sup 234}U)/n({sup 235}U) ratios and 5-25 percent for the n({sup 236}U)/n({sup 235}U) ratios were achieved. The purpose of the study was to establish a register of isotopic signatures for natural uranium materials. The amount ratio, and isotopic composition of 18 ore concentrates, collected by the International

  17. The determination of minor isotope abundances in naturally occurring uranium materials. The tracing power of isotopic signatures for uranium

    International Nuclear Information System (INIS)

    Ovaskainen, R.

    1999-01-01

    The mass spectrometric determination of minor abundant isotopes, 234 U and 236 U in naturally occurring uranium materials requires instruments of high abundance sensitivity and the use of highly sensitive detection systems. In this study the thermal ionisation mass spectrometer Finnigan MAT 262RPQ was used. It was equipped with 6 Faraday cups and a Secondary Electron Multiplier (SEM), which was operated in pulse counting mode for the detection of extremely low ion currents. The dynamic measurement range was increased considerably combining these two different detectors. The instrument calibration was performed carefully. The linearity of each detector, the deadtime of the ion counting detector, the detector normalisation factor, the baseline of each detector and the mass discrimination in the ion source were checked and optimised. A measurement technique based on the combination of a Gas Source Mass Spectrometry (GSMS) and a Thermal Ionisation Mass Spectrometry (TIMS) was developed for the accurate determination of isotopic composition in naturally occurring uranium materials. Because the expected ratio of n( 234 U)/n( 238 U) exceeded the dynamic measurement range of the Faraday detectors of the TIMS instrument, an experimental design using a combination of two detectors was developed. The n( 234 U)/n( 235 U) and n( 236 U)/n( 235 U) ratios were determined using ion counting in combination with the decelerating device. The n( 235 U)/n( 238 U) ratio was determined by the Faraday detector. This experimental design allowed the detector cross calibration to be circumvented. Precisions of less than 1 percent for the n( 234 U)/n( 235 U) ratios and 5-25 percent for the n( 236 U)/n( 235 U) ratios were achieved. The purpose of the study was to establish a register of isotopic signatures for natural uranium materials. The amount ratio, and isotopic composition of 18 ore concentrates, collected by the International Atomic Energy Agency (IAEA) from uranium milling and mining

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

    Science.gov (United States)

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

    1975-01-01

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

  19. Formulating natural based cosmetic product - irradiated herbal lip balm

    International Nuclear Information System (INIS)

    Seri Chempaka Mohd Yusof; Ros Anita Ahmad Ramli; Foziah Ali; Zainab Harun

    2007-01-01

    Herbal lip balm was formulated in efforts to produce a safe product, attractive with multifunctional usage i.e. prevent chap lips, reduce mouth odour and benefits in improving the health quality. Problems faced in constructing formulations of herbal lip balm were focused to the extraction of anthocyanins, the stability of the pigments in the formulations and changes of colour during irradiation for the sterilization of herbal lip balm. Natural pigment, anthocyanin was used as a colorant agent in herbal lip balm, obtained from various herbs and vegetables i.e. Hibiscus sabdariffa L. (roselle), Brassica oleracea var. capitata f. rubra (red cabbage) and Daucus carota (carrot). Water based extraction method was used in extracting the anthocyanins. The incorporation of honey in the formulations improved the colour of the lip balm. The usage of plant based ingredient i.e. cocoa butter substituting the normal based ingredient i.e. petroleum jelly in lip balm also affecting the colour of herbal lip balm. Irradiation at 2.5, 5.0 and 10 kGy was carried out as preservation and reducing of microbial load of the herbal lip balm and changes in colour were observed in formulations irradiated at 10 kGy. (Author)

  20. Contribution of analytical techniques coupled to the knowledge of the uranium speciation in natural conditions

    International Nuclear Information System (INIS)

    Petit, J.

    2009-06-01

    To understand the transport mechanisms and the radionuclides behaviour in the bio-geosphere is necessary to evaluate healthy and environmental risks of nuclear industry. These mechanisms are monitored by radioelements speciation, namely the distribution between their different physico-chemical forms in the environment. From this perspective, this PhD thesis deals with uranium speciation in a natural background. A detailed summary of uranium biogeochemistry has been written, which enables to restrict the PhD issue to uranium complexation with oxalic acid, a hydrophilic organic acid with good binding properties, ubiquitous in soil waters. Analytical conditions have been established by means of speciation diagrams. The speciation diagrams building by means of literature stability constants has allowed to define the analytical conditions of complex formation. The chosen analytical technique is the hyphenation of a separative technique (liquid chromatography LC or capillary electrophoresis CE) with mass spectrometry (ICPMS). The studied complexes presence in the synthetic samples has been confirmed with UV/visible spectrophotometry. LC-ICPMS analyses have proved the lability of the uranyl-organic acid complexes, namely their tendency to dissociate during analysis, which prevents from studying uranium speciation. CE-ICPMS study of labile complexes from a metal-ligand system has been made possible by employing affinity capillary electrophoresis, which enables to determine stability constants and electrophoretic mobilities. This PhD thesis has allowed to compare the different mathematical treatments of binding isotherm and to take into account ionic strength and real ligand concentration. Affinity CE has been applied successfully to lanthanum-oxalate (model system) and uranium-oxalate systems. The obtained results have been applied to a real system (situated in Le Bouchet). This shows the contribution of the developed method to the modelling of uranium speciation. (author)

  1. 238 U 92 radionuclide handbook. Natural Uranium and environment

    International Nuclear Information System (INIS)

    Garnier-Laplace, J.; Colle, C.; Morello, M.

    2001-01-01

    This handbook summarizes the behaviour of the chemical element in the main compartments of land and aquatic ecosystems, under the two following assumptions: isotopic discrimination is negligible (this is validated for most of the examined elements); when the element possesses stable isotopes, the behaviour analogy between its stable and radioactive isotopes is implicitly admitted, knowing that, for elements existing at the natural state, the chemical form and the emitting media of the anthropic effluents are susceptible of implying other transfer processes than those identified for the natural stable element. The handbook gives information on the chemical and nuclear characteristics of the element, its origins, the concentrations in the environment, the mobility and bio-availability in land ecosystems (soils, plants, animals) and aquatic ecosystems (waters, sediments, plants, animals)

  2. Electricity generation with natural gas or with uranium?

    International Nuclear Information System (INIS)

    Villanueva M, C.

    2009-10-01

    The program of works and investments of electric sector that actualize each year the Federal Commission of Electricity, include to the projects of electric power generating stations that will begin its commercial operation inside the horizon of the next ten years, in order to satisfy opportunely with appropriate reservation margins the demand of power and energy in the national interconnected system that grows year to year. In spite of its inherent advantages, in the electric sector prospective 2008-2017 are not considered explicitly to the nuclear power plants, except for the small amplification of capacity of nuclear power plant of Laguna Verde, that already is executing. In this context, the objective of this work is to present and to discuss arguments to favor and against the combined cycle and nuclear technologies, to indicate the risks and disadvantages in that it incurs the electric sector when leaning on so disproportionately on the fossil fuels for the electricity generation, in particular the natural gas, deferring to an indefinite future the installation of nuclear plants whose proven technology is economic, sure, clean and reliable and it contributes decisively to the national energy security. To mitigate the harmful effects of excessive dependence on natural gas to generate electric power, was propose alternatives to the expansion program of electric sector to year 2017, which would have as benefits the decrease of the annual total cost of electric power supply for public service, the significant reduction of natural gas imports and emissions reduction of CO 2 to the atmosphere. (Author)

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

    International Nuclear Information System (INIS)

    Mondani, L.

    2010-01-01

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

  4. Uranium pollution in an estuary affected by pyrite acid mine drainage and releases of naturally occurring radioactive materials

    International Nuclear Information System (INIS)

    Villa, M.; Manjon, G.; Hurtado, S.; Garcia-Tenorio, R.

    2011-01-01

    Highlights: → Huelva estuary is affected by former phosphogypsum releases and pyrite acid mine drainage. → Time evolution of uranium concentration is analyzed after halting of NORM releases. → Two new contamination sources are preventing the complete uranium cleaning: (1) The leaching of phosphogypsum stacks located close to Tinto River. (2) Pyrite acid mine drainage. → High uranium concentrations are dissolved in water and precipitate subsequently. - Abstract: After the termination of phosphogypsum discharges to the Huelva estuary (SW Spain), a unique opportunity was presented to study the response of a contaminated environmental compartment after the cessation of its main source of pollution. The evolution over time of uranium concentrations in the estuary is presented to supply new insights into the decontamination of a scenario affected by Naturally Occurring Radioactive Material (NORM) discharges. The cleaning of uranium isotopes from the area has not taken place as rapidly as expected due to leaching from phosphogypsum stacks. An in-depth study using various techniques of analysis, including 234 U/ 238 U and 230 Th/ 232 Th ratios and the decreasing rates of the uranium concentration, enabled a second source of uranium contamination to be discovered. Increased uranium levels due to acid mine drainage from pyrite mines located in the Iberian Pyrite Belt (SW Spain) prevent complete uranium decontamination and, therefore, result in levels nearly twice those of natural background levels.

  5. The uranium source-term mineralogy and geochemistry at the Broubster natural analogue site, Caithness

    International Nuclear Information System (INIS)

    Milodowski, A.E.; Pearce, J.M.; Basham, I.R.; Hyslop, E.K.

    1991-01-01

    The British Geological Survey (BGS) has been conducting a coordinated research programme at the Broubster natural analogue site in Caithness, north Scotland. This work on a natural radioactive geochemical system has been carried out with the aim of improving our confidence in using predictive models of radionuclide migration in the geosphere. This report is one of a series being produced and it concentrates on the mineralogical characterization of the uranium distribution in the limestone unit considered as the 'source-term' in the natural analogue model

  6. Measurement conditions of natural soil thermoluminescence and their application in a granite type uranium deposit

    International Nuclear Information System (INIS)

    Chen Yue; Yang Yaxin; Liu Qingcheng

    2009-01-01

    A measuring method of natural soil thermoluminescence is used for prospecting of uranium deposits. The better effects are obtained by using the method, but the parameters selected have significant effects on the intensity of soil thermoluminescent. So, the measuring parameters are selected according to the different soil samples. Based on the measuring 1 000 soil samples of granite type uranium deposit,the optimum heating up program of natural soil thermoluminescence is obtained, that is, preheating, lasting heating, constant temperature and the halting heating. The parameters selected are as follows: the heating rate being 15 degree C/s, the temperatures of the first and second constant temperature being 135 degree C and 400 degree C respectively. Using the selected parameters for measuring soil samples from a known mining area in Guangdong province, the result indicates that the abnormities of thermoluminescence have corresponding relations with the underground orebodies. (authors)

  7. 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

  8. Analytical strategies for uranium determination in natural water and industrial effluents samples

    International Nuclear Information System (INIS)

    Santos, Juracir Silva

    2011-01-01

    The work was developed under the project 993/2007 - 'Development of analytical strategies for uranium determination in environmental and industrial samples - Environmental monitoring in the Caetite city, Bahia, Brazil' and made possible through a partnership established between Universidade Federal da Bahia and the Comissao Nacional de Energia Nuclear. Strategies were developed to uranium determination in natural water and effluents of uranium mine. The first one was a critical evaluation of the determination of uranium by inductively coupled plasma optical emission spectrometry (ICP OES) performed using factorial and Doehlert designs involving the factors: acid concentration, radio frequency power and nebuliser gas flow rate. Five emission lines were simultaneously studied (namely: 367.007, 385.464, 385.957, 386.592 and 409.013 nm), in the presence of HN0 3 , H 3 C 2 00H or HCI. The determinations in HN0 3 medium were the most sensitive. Among the factors studied, the gas flow rate was the most significant for the five emission lines. Calcium caused interference in the emission intensity for some lines and iron did not interfere (at least up to 10 mg L -1 ) in the five lines studied. The presence of 13 other elements did not affect the emission intensity of uranium for the lines chosen. The optimized method, using the line at 385.957 nm, allows the determination of uranium with limit of quantification of 30 μg L -1 and precision expressed as RSD lower than 2.2% for uranium concentrations of either 500 and 1000 μg L -1 . In second one, a highly sensitive flow-based procedure for uranium determination in natural waters is described. A 100-cm optical path flow cell based on a liquid-core waveguide (LCW) was exploited to increase sensitivity of the arsenazo 111 method, aiming to achieve the limits established by environmental regulations. The flow system was designed with solenoid micro-pumps in order to improve mixing and minimize reagent consumption, as well as

  9. The experimental determination of the buckling in the bare heavy water natural uranium critical assembly 'RB'

    Energy Technology Data Exchange (ETDEWEB)

    Raisic, N M; Popovic, D D; Takac, S M; Djordjevic, M M [Boris Kidric Institute of Nuclear Sciences, Vinca, Beograd (Yugoslavia)

    1960-03-15

    The buckling in the bare heavy water natural uranium critical assembly was determined by measuring the thermal neutron flux distribution. The obtained value for the critical buckling at the temperature of 20 deg C is: B{sup 2} = (8.516 {+-} 0.02) m{sup -2}. The above error is a statistical one, obtained from several series of measurements. The possible systematic error was estimated as 0.1 m{sup -2}. (author)

  10. Dating by fission track method: study of neutron dosimetry with natural uranium thin films

    International Nuclear Information System (INIS)

    Iunes, P.J.

    1990-06-01

    Fission track dating is described, focalizing the problem of the decay constant for spontaneous fission of 238 U and the use of neutron dosimetry in fission track analysis. Experimental procedures using thin films of natural uranium as neutron dosimeters and its results are presented. The author shows a intercomparison between different thin films and between the dosimetry with thin film and other dosimetries. (M.V.M.). 52 refs, 12 figs, 9 tabs

  11. The experimental determination of the buckling in the bare heavy water natural uranium critical assembly 'RB'

    International Nuclear Information System (INIS)

    Raisic, N.M.; Popovic, D.D.; Takac, S.M.; Djordjevic, M.M.

    1960-01-01

    The buckling in the bare heavy water natural uranium critical assembly was determined by measuring the thermal neutron flux distribution. The obtained value for the critical buckling at the temperature of 20 deg C is: B 2 = (8.516 ± 0.02) m -2 . The above error is a statistical one, obtained from several series of measurements. The possible systematic error was estimated as 0.1 m -2 . (author)

  12. External dose distributions of exposure to natural uranium slab for calibration of beta absorbed dose

    International Nuclear Information System (INIS)

    Chen Lishu

    1987-01-01

    The depth dose distributions and uniformity of beta radiation fields from a natural uranium slab in equilibration were measured using a tissue equivalent extrapolation chamber and film dosimeter. The advantages for calibration of enviromental dose instument or survey meter and personal dosimeter, for routine monitoring in terms of directional dose equivalent and superficial individual dose equivalent were summarized. Finally, the values measured agree well with that of theoretical calculation

  13. External dose distributions of exposure to natural uranium slab for calibration of beta absorbed dose

    Energy Technology Data Exchange (ETDEWEB)

    Lishu, Chen

    1987-05-01

    The depth dose distributions and uniformity of beta radiation fields from a natural uranium slab in equilibration were measured using a tissue equivalent extrapolation chamber and film dosimeter. The advantages for calibration of enviromental dose instument or survey meter and personal dosimeter, for routine monitoring in terms of directional dose equivalent and superficial individual dose equivalent were summarized. Finally, the values measured agree well with that of theoretical calculation.

  14. An evaluation of the dissolution process of natural uranium ore as an analogue of nuclear fuel

    International Nuclear Information System (INIS)

    Stern, V.H.

    1991-08-01

    The assumption of congruent dissolution of uraninite as a mechanism for the dissolution behaviour of spent fuel was critically examined with regard to the fate of toxic radionuclides. The fission and daughter products of uranium are typically present in spent unreprocessed fuel rods in trace abundances. The principles of trace element geochemistry were applied in assessing the behaviour of these radionuclides during fluid/solid interactions. It is shown that the behaviour of radionuclides in trace abundances that reside in the crystal structure can be better predicted from the ionic properties of these nuclides rather than from assuming that they are controlled by the dissolution of uraninite. Geochemical evidence from natural uranium ore deposits (Athabasca Basin, Northern Territories of Australia, Oklo) suggests that in most cases the toxic radionuclides are released from uraninite in amounts that are independent of the solution behaviour of uranium oxide. Only those elements that have ionic and thus chemical properties similar to U 4+ , such as plutonium, americium, cadmium, neptunium and thorium can be satisfactorily modelled by the solution properties of uranium dioxide and then only if the environment is reducing. (84 refs., 7 tabs.)

  15. Determination of ultratrace concentrations of uranium and thorium in natural waters by x-ray fluorescence

    International Nuclear Information System (INIS)

    Stewart, J.H. Jr.; Brooksbank, R.D.

    1981-01-01

    An x-ray fluorescence method for the simultaneous determination of uranium and thorium at the less than 1 ppM level in natural waters is described. Uranium and thorium are coprecipitated with an internal standard, yttrium, and incorporated into an iron-aluminum hydroxide carrier. The hydroxide precipitate is filtered, and the filter disk is analyzed by the energy-dispersive x-ray fluorescence technique. Matrix interferences caused by the presence of unpredictable anions and cations are compensated for by the internal standard. The U/Y and Th/Y ratios are linear over the 5- to 100-μg range of interest, and the detection limit of each element on the filter disk is 2 μg (3 sigma). Relative standard deviation was 17% at the 15-μg and 4% at the 100-μg level for thorium and 11% at the 11-μg and 2% at the 100-μg level for uranium. Analysis of spiked solutions showed a recovery of 19.6 +- 0.3 μg for uranium and 19.8 +- 0.3 μg for thorium at the 20-μg level, and the normal lower reporting limit is 5 μg. Fifty disks can be routinely measured during a normal working day

  16. Natural radioactivity, dose assessment and uranium uptake by agricultural crops at Khan Al-Zabeeb, Jordan

    Energy Technology Data Exchange (ETDEWEB)

    Al-Kharouf, Samer J. [Royal Scientific Society, Amman 11941 (Jordan); Al-Hamarneh, Ibrahim F. [Prince Abdullah Bin Ghazi Faculty of Science and IT, Al-Balqa Applied University (BAU), Salt 19117 (Jordan)], E-mail: hamarnehibrahim@yahoo.com; Dababneh, Munir [Prince Abdullah Bin Ghazi Faculty of Science and IT, Al-Balqa Applied University (BAU), Salt 19117 (Jordan)

    2008-07-15

    Khan Al-Zabeeb, an irrigated cultivated area lies above a superficial uranium deposits, is regularly used to produce vegetables and fruits consumed by the public. Both soil and plant samples collected from the study area were investigated for their natural radioactivity to determine the uranium uptake by crops and hence to estimate the effective dose equivalent to human consumption. Concentrations of {sup 238}U, {sup 235}U, {sup 232}Th, {sup 226}Ra, {sup 222}Rn, {sup 137}Cs and {sup 40}K in nine soil profiles were measured by gamma-ray spectrometry whereas watermelon and zucchini crops were analyzed for their uranium content by means of alpha spectrometry after radiochemical separation. Correlations between measured radionuclides were made and their activity ratios were determined to evaluate their geochemical behavior in the soil profiles. Calculated soil-plant transfer factors indicate that the green parts (leaves, stems and roots) of the studied crops tend to accumulate uranium about two orders of magnitude higher than the fruits. The maximum dose from ingestion of 1 kg of watermelon pulp was estimated to be 3.1 and 4.7 nSv y{sup -1} for {sup 238}U and {sup 234}U, respectively. Estimations of the annual effective dose equivalent due to external exposure showed extremely low values. Radium equivalent activity and external hazard index were seen to exceed the permissible limits of 370 Bq kg{sup -1} and 1, respectively.

  17. Natural radioactivity, dose assessment and uranium uptake by agricultural crops at Khan Al-Zabeeb, Jordan

    International Nuclear Information System (INIS)

    Al-Kharouf, Samer J.; Al-Hamarneh, Ibrahim F.; Dababneh, Munir

    2008-01-01

    Khan Al-Zabeeb, an irrigated cultivated area lies above a superficial uranium deposits, is regularly used to produce vegetables and fruits consumed by the public. Both soil and plant samples collected from the study area were investigated for their natural radioactivity to determine the uranium uptake by crops and hence to estimate the effective dose equivalent to human consumption. Concentrations of 238 U, 235 U, 232 Th, 226 Ra, 222 Rn, 137 Cs and 40 K in nine soil profiles were measured by gamma-ray spectrometry whereas watermelon and zucchini crops were analyzed for their uranium content by means of alpha spectrometry after radiochemical separation. Correlations between measured radionuclides were made and their activity ratios were determined to evaluate their geochemical behavior in the soil profiles. Calculated soil-plant transfer factors indicate that the green parts (leaves, stems and roots) of the studied crops tend to accumulate uranium about two orders of magnitude higher than the fruits. The maximum dose from ingestion of 1 kg of watermelon pulp was estimated to be 3.1 and 4.7 nSv y -1 for 238 U and 234 U, respectively. Estimations of the annual effective dose equivalent due to external exposure showed extremely low values. Radium equivalent activity and external hazard index were seen to exceed the permissible limits of 370 Bq kg -1 and 1, respectively

  18. The Effect of Gamma Irradiation on the Mechanical Properties of vulcanized Natural Rubber and Natural Rubber-Polyethylene Blends

    International Nuclear Information System (INIS)

    Sudradjat Iskandar

    2008-01-01

    To enhance the quality of vulcanized natural rubber and natural rubber-polyethylene blends, gamma irradiation has been done. The compound of natural rubber and natural rubber-polyethylene blends made by using roll mill machine. The mixed materials were antioxidant, anti ozon, plasticizer and vulcanisator. The natural rubber and natural rubber-polyethylene blends compound were vulcanizer and made a slab (film of sample) using hot and could press machine. The slabs produced were then gamma irradiated at irradiation dose of 75, 150 and 300 kGy. Before and after irradiation, the slab were characterized using strograph R1 machine. The results showed that the modulus 300 and hardness of vulcanized natural rubber and natural rubber-polyethylene blends were increasing; the tensile strength and tear strength were increasing to maximum level then decreasing with gamma irradiation, while the elongation at break was decreasing. The maximum tensile strength of vulcanized natural rubber and natural rubber-polyethylene blends were found at irradiation dose of 75 kGy. At the irradiation dose of 75 kGy, the tensile strength of vulcanized natural rubber increased from 17.6 MN/m 2 to 21.2 MN/m 2 , while the tensile strength of vulcanized natural rubber-polyethylene blends increased slightly from 18.7 MN/m 2 to 19.4 MN/m 2 . (author)

  19. Laboratory studies on natural restoration of ground water after in-situ leach uranium mining

    International Nuclear Information System (INIS)

    Bell, N.E.; Deutsch, W.J.; Serne, R.J.

    1983-05-01

    When uranium is mined using in-situ leach techniques, the chemical quality of the ground water in the ore-zone aquifer is affected. This could lead to long-term degradation of the ground water if restoration techniques are not applied after the leaching is completed. Pacific Northwest Laboratory (PNL), is conducting an NRC-sponsored research project on natural restoration and induced-restoration techniques. Laboratory studies were designed to evaluate the ability of the natural system (ore-zone sediments and groundwater) to mitigate the effects of mining on aquifer chemistry. Using batch and flow-through column experiments [performed with lixiviant (leaching solution) and sediments from the reduced zone of an ore-zone aquifer], we found that the natural system can lower uranium and bicarbonate concentrations in solutions and reduce the lixiviant redox potential (Eh). The change in redox potential could cause some of the contaminants that were dissolved during the uranium leaching operation to precipitate, thereby lowering their solution concentration. The concentrations of other species such as calcium, potassium, and sulfate increased, possibly as a result of mineral dissolution and ion exchange. In this paper, we describe the experimentally determined mobility of contaminants after in-situ leach mining, and discuss the possible chemical process affecting mobility

  20. Laboratory studies on natural restoration of ground water after in-situ leach uranium mining

    Energy Technology Data Exchange (ETDEWEB)

    Bell, N.E.; Deutsch, W.J.; Serne, R.J.

    1983-05-01

    When uranium is mined using in-situ leach techniques, the chemical quality of the ground water in the ore-zone aquifer is affected. This could lead to long-term degradation of the ground water if restoration techniques are not applied after the leaching is completed. Pacific Northwest Laboratory (PNL), is conducting an NRC-sponsored research project on natural restoration and induced-restoration techniques. Laboratory studies were designed to evaluate the ability of the natural system (ore-zone sediments and groundwater) to mitigate the effects of mining on aquifer chemistry. Using batch and flow-through column experiments (performed with lixiviant (leaching solution) and sediments from the reduced zone of an ore-zone aquifer), we found that the natural system can lower uranium and bicarbonate concentrations in solutions and reduce the lixiviant redox potential (Eh). The change in redox potential could cause some of the contaminants that were dissolved during the uranium leaching operation to precipitate, thereby lowering their solution concentration. The concentrations of other species such as calcium, potassium, and sulfate increased, possibly as a result of mineral dissolution and ion exchange. In this paper, we describe the experimentally determined mobility of contaminants after in-situ leach mining, and discuss the possible chemical process affecting mobility.

  1. Uranium

    International Nuclear Information System (INIS)

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

    1988-01-01

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

  2. Application for assistance to United Nations rotating fund for the study of natural resources, for uranium prospecting

    International Nuclear Information System (INIS)

    1976-01-01

    This memoranda is a United Nations petition about natural resources study which allow the uranium prospecting. These areas will be studied on sedentary, anomalous and crystal land as well as radiometric rises

  3. Analysis for the radionuclides of the natural uranium and thorium decay chains with special reference to uranium mine tailings

    International Nuclear Information System (INIS)

    Lowson, R.T.; Short, S.A.

    1986-08-01

    A detailed review is made of the experimental techniques that are available, or are in the process of development, for the determination of 238 U, 235 U, 234 U, 231 Pa, 232 Th, 230 Th, 228 Th, 228 Ra, 226 Ra, 223 Ra, 210 Po and 210 Pb. These products of the uranium and thorium decay chains are found in uranium mine tailings. Reference is also made to a procedure for the selective phase extraction of mineral phases from uranium mine tailings

  4. Status of the natural and enriched uranium market: the basic economical factor for the development of the fuel cycle

    International Nuclear Information System (INIS)

    Nochev, T.

    1999-01-01

    Status of the Natural and Enriched Uranium Market - the Basic. Economical Factor for the Development of the Fuel Cycle An overview of the status of the natural and enriched uranium market has been performed and it offers a possibility to estimate the changes and tendencies, the knowledge of which is needed in negotiations about the fresh fuel. The simplified financial analysis presented here demonstrates the economical profitability of the storage of the spent fuel making now the allocations for the future reprocessing

  5. Behavior studies of natural uranium radioactive families descendants in organic rich sediments: the sapropels

    International Nuclear Information System (INIS)

    Gourgiotis, A.

    2008-06-01

    The element uranium with the particular oxido-reducing properties is often associated with environments rich in organic matter; this is why several authors have proposed to use it as tracer of paleo-productivity in marine sediments. This work describes the distribution of the uranium natural families' radionuclides in organic rich Mediterranean sediments: the sapropels. Several techniques of measurements were used such as mass spectrometry (TIMS, ICP-QMS), alpha and gamma spectrometry. Activity ratios 234 U/ 238 U as well as the ages U-Th of the sapropels present irregular profiles which do not correspond to the assumptions which had been made to explain their formation. Using an 1D diffusion model we have showed that these profiles result from the migration of the radionuclides out of the sapropels. We validated these observations by analyzing several levels of sapropels presenting a spatio-temporal variability. Our study confirms the migration of radiogenic uranium 234 U rad , which is produced in situ by his father the 238 U, as well as the migration of the 226 Ra. However the mobility of radiogenic uranium ( 234 U rad ) is not sufficient to explain the drift of the 230 Th/ 238 U and 231 Pa/ 235 U activity ratios in the S5 sapropel. An important result is that authigenic uranium also migrates, but with lower effective diffusion coefficients than those of the 234 U rad . Because of this mobility, the use of U authigenic of the sediments as an indicator of paleo-productivity must thus be used with precaution. (author)

  6. Validation of gamma-ray detection techniques for safeguards monitoring at natural uranium conversion facilities

    Energy Technology Data Exchange (ETDEWEB)

    Dewji, S.A., E-mail: dewjisa@ornl.gov [Oak Ridge National Laboratory, 1 Bethel Valley Road, MS-6335, Oak Ridge, TN 37831-6335 (United States); Lee, D.L.; Croft, S. [Oak Ridge National Laboratory, 1 Bethel Valley Road, MS-6335, Oak Ridge, TN 37831-6335 (United States); Hertel, N.E. [Oak Ridge National Laboratory, 1 Bethel Valley Road, MS-6335, Oak Ridge, TN 37831-6335 (United States); Nuclear and Radiological Engineering Program, Georgia Institute of Technology, 770 State Street, Atlanta, GA 30332-0745 (United States); Chapman, J.A.; McElroy, R.D.; Cleveland, S. [Oak Ridge National Laboratory, 1 Bethel Valley Road, MS-6335, Oak Ridge, TN 37831-6335 (United States)

    2016-07-01

    Recent IAEA circulars and policy papers have sought to implement safeguards when any purified aqueous uranium solution or uranium oxides suitable for isotopic enrichment or fuel fabrication exists. Under the revised policy, IAEA Policy Paper 18, the starting point for nuclear material under safeguards was reinterpreted, suggesting that purified uranium compounds should be subject to safeguards procedures no later than the first point in the conversion process. In response to this technical need, a combination of simulation models and experimental measurements were employed to develop and validate concepts of nondestructive assay monitoring systems in a natural uranium conversion plant (NUCP). In particular, uranyl nitrate (UO{sub 2}(NO{sub 3}){sub 2}) solution exiting solvent extraction was identified as a key measurement point (KMP), where gamma-ray spectroscopy was selected as the process monitoring tool. The Uranyl Nitrate Calibration Loop Equipment (UNCLE) facility at Oak Ridge National Laboratory was employed to simulate the full-scale operating conditions of a purified uranium-bearing aqueous stream exiting the solvent extraction process in an NUCP. Nondestructive assay techniques using gamma-ray spectroscopy were evaluated to determine their viability as a technical means for drawing safeguards conclusions at NUCPs, and if the IAEA detection requirements of 1 significant quantity (SQ) can be met in a timely way. This work investigated gamma-ray signatures of uranyl nitrate circulating in the UNCLE facility and evaluated various gamma-ray detector sensitivities to uranyl nitrate. These detector validation activities include assessing detector responses to the uranyl nitrate gamma-ray signatures for spectrometers based on sodium iodide, lanthanum bromide, and high-purity germanium detectors. The results of measurements under static and dynamic operating conditions at concentrations ranging from 10–90 g U/L of natural uranyl nitrate are presented. A range of

  7. Recovery of Ra-223 from natural thorium irradiated by protons

    Energy Technology Data Exchange (ETDEWEB)

    Vasiliev, Aleksandr N.; Ostapenko, Valentina S. [Lomonosov Moscow State Univ. (Russian Federation); Russian Academy of Sciences, Moscow-Troitsk (Russian Federation). Inst. for Nuclear Research; Lapshina, Elena V.; Ermolaev, Stanislav V.; Zhuikov, Boris L. [Russian Academy of Sciences, Moscow-Troitsk (Russian Federation). Inst. for Nuclear Research; Danilov, Sergey S. [Lomonosov Moscow State Univ. (Russian Federation); Kalmykov, Stepan N. [Lomonosov Moscow State Univ. (Russian Federation); National Research Center ' Kurchatov Institute' (NRC ' Kurchatov Institute' ), Moscow (Russian Federation)

    2016-11-01

    Irradiation of natural thorium with medium-energy protons is considered to be a prospective approach to large-scale production of {sup 225}Ac and {sup 223}Ra. In addition to the earlier-developed method of {sup 225}Ac isolation, the present work focuses on the simultaneous recovery of {sup 223}Ra from the same thorium target. Radiochemical procedure is based on liquid-liquid extraction, cation exchange and extraction chromatography. The procedure provides separation of radium from spallation and fission products generated in the thorium target. High chemical yield (85-90%) and radionuclide purity of {sup 223}Ra (> 99.8% except {sup 224}Ra and {sup 225}Ra isotopes) have been achieved.

  8. Uranium mineral - groundwater equilibrium at the Palmottu natural analogue study site, Finland

    International Nuclear Information System (INIS)

    Ahonen, L.; Ruskeeniemi, T.; Blomqvist, R.; Ervanne, H.; Jaakkola, T.

    1993-01-01

    The redox-potential, pH, chemical composition of fracture waters, and uraninite alteration associated with the Palmottu uranium mineralization (a natural analogue study site for radioactive waste disposal in southwestern Finland), have been studied. The data have been interpreted by means of thermodynamic calculations. The results indicate equilibrium between uraninite, ferric hydroxide and groundwater in the bedrock of the study site. Partially oxidized uraninite (UO 2 .33) and ferric hydroxide are in equilibrium with fresh, slightly acidic and oxidized water type, while primary uraninite is stable with deeper waters that have a higher pH and lower Eh. Measured Eh-pH values of groundwater cluster within a relatively narrow range indicating buffering by heterogenous redox-processes. A good consistency between measured Eh and analyzed uranium oxidation states was observed

  9. Study of natural thermoluminescence of quartzite in a gold and uranium mineralized zone (Canavieiras, Jacobina, Brazil)

    International Nuclear Information System (INIS)

    Ferreira, J.; Nordemann, D.

    1976-01-01

    The quartzite of the Canavieiras gold mine (Jacobina, Bahia, Brazil) exhibits a high temperature peak (280 +- 2) 0 C in its natural thermoluminescence glow curve. It was experimentally determined that the amount of light in this peak could be reproduced to within 5% for grain sizes between 80 and 100 mesh (0.149 and 0.177 mm). A positive correlation was found between the amount of this thermoluminescence and the uranium content with saturation beginning to be detected at the maximum (700 ppm) amount of uranium found. Assuming that the thermoluminescence peak used is at a temperature high enough to permit accumulation and stability at room temperatures, the thermoluminescence found could have accumulated in (12.1 +- 0.3) x 10 6 years. This may date a complete liberation of trapped electrons in conjunction with a well documented initiation of weathering. (author) [pt

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  11. The geochemical immobilization of uranium in a spent fuel repository in the Canadian Shield: Evidence from natural analogue investigations

    International Nuclear Information System (INIS)

    Bottomley, D.J.

    1996-04-01

    Natural analogue studies of uranium ore deposits provide valuable information on the geochemical conditions that control the mobilization of uranium and associated radionuclides in groundwaters. At Cigar Lake in northern Saskatchewan, the Pocos de Caldas site in Brazil, and at Palmottu in Finland, groundwaters are sufficiently reducing to prevent significant oxidation of U +4 to the more soluble U +6 oxidation state. Despite being one of the richest uranium deposits in the world, uranium concentrations in the groundwaters around the Cigar Lake ore are less than 5 x 10 -8 M. Even under oxiding conditions uranium may not necessarily be highly mobilized by groundwaters. Studies of the relatively shallow uranium ore deposits in the Alligator Rivers region of Australia have shown that uranium transport by groundwater can be limited because of uranium sorption onto secondary iron oxides within the aquifer. However, studies at 'negative analgoue' sites indicate that where the host rocks contain low concentrations of reductants such as iron sulphides, strongly reducing conditions are not established and high concentrations of dissolved uranium can result, even in areas where uranium ore deposits are not known to occur. The release rate of radionuclides from a spent fuel repository will be strongly dependent on the redox conditions that are established following resaturation of the repository. Groundwater at depths of 500 m in a granitic pluton may not be sufficiently reducing to prevent oxidative dissolution of uranium or oxidation of associated radionuclides such as 99 Tc. Accordingly other shield rocks richer in reductants, such as greenstone belts, should be considered as potential host rocks for a repository or the repository should be constructed at depths closer to 1000 m in granitic rock where more reducing conditions are likely to prevail. Alternatively, addition of reductants to the waste containers may be feasible as a means of maintaining reducing conditions

  12. Determination of the natural Uranium in the ecosystems around the site of INR-Pitesti

    International Nuclear Information System (INIS)

    Horhoianu, V.; Todoran, A.; Valeca, M.; Hirica, O.

    2002-01-01

    Natural radioactivity, a basic component of the environment, is determined by the presence in soil, atmosphere, water, vegetation, live elements and humans of radioactive matter of terrestrial origin, naturally existing from the very beginning. To all these, extra-terrestrial cosmic radiation must be added. Human exposure to terrestrial radiation is due to radionuclides present in the earth crust or to those transferred from atmosphere or hydrosphere. An abundance of radionuclides present in the crust are radioactive. Their lifetime is shorter or equal to the estimated age of the earth crust and, consequently, they are presumed to represent a primordial inventory. Uranium and thorium in natural state decay in three different series, the first ones being the radionuclides 2 38U , 2 35U and 2 32T h. The population exposure to radiation must take into account both natural and artificial radiation

  13. The study of neutron propagation in natural uranium; Etude de la propagation des neutrons dans l'uranium naturel

    Energy Technology Data Exchange (ETDEWEB)

    Campan, J L; Clauzon, P P; Kirchner, B; Ribon, P; Zaleski, C P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1961-07-01

    Fast exponential experiment. Experimental facilities are described; the experimental results obtained with the block of natural uranium are then presented. Detectors used were fission chambers, activation detectors and nuclear emulsions. One tries to explain the results, which are, then compared with theoretical values obtained by calculations based on diffusion theory. Measured spectrum (pseudo equilibrium) may be characterised by the following values: diffusion length: 95,25 {+-} 0,5; {sigma}{sub f}U{sub 235}/{sigma}{sub f}U{sub 238} : 230 {+-} 10, {sigma}{sub f}U{sub 235}/{sigma}{sub f}Np{sub 237} : 14 {+-} 0.5, {sigma}{sub f}U{sub 235}/{sigma}{sub f}U{sub 233} : 0.67 {+-} 0.03, {sigma}{sub f}U{sub 235}/{sigma}{sub f}Pu{sub 239} : 0.90 {+-} 0.05, {sigma}{sub f}U{sub 235}/{sigma}(ny) In : 230 {+-}10. (author) [French] Experience exponentielle rapide. Apres une description du dispositif experimental, on presente des resultats de mesures effectuees dans un massif d'uranium naturel. Les detecteurs utilises sont des chambres a fission, des detecteurs d'activation et des emulsions nucleaires. Une interpretation des resultats est donnee; ceux-ci sont compares a des valeurs theoriques obtenues par des calculs utilisant la theorie de la diffusion. Le spectre mesure (pseudo equilibre) peut etre caracterise par les valeurs suivantes: Longueur de diffusion: 95,25 {+-} 0,5; {sigma}{sub f}U{sub 235}/{sigma}{sub f}U{sub 238} : 230 {+-} 10, {sigma}{sub f}U{sub 235}/{sigma}{sub f}Np{sub 237} : 14 {+-} 0.5, {sigma}{sub f}U{sub 235}/{sigma}{sub f}U{sub 233} : 0.67 {+-} 0.03, {sigma}{sub f}U{sub 235}/{sigma}{sub f}Pu{sub 239} : 0.90 {+-} 0.05, {sigma}{sub f}U{sub 235}/{sigma}(ny) In : 230 {+-}10. (auteur)

  14. On the separation of so-called non-volatile uranium fission products of uranium using the conversion of neutron-irradiated uranium dioxide and graphite

    International Nuclear Information System (INIS)

    Elhardt, W.

    1979-01-01

    The investigations are continued in the following work which arose from the concept of separating uranium fission products from uranium. This is achieved in that due to the lattice conversions occurring during the course of solid chemical reactions, fission products can easily pass from the uranium-contained solid to a second solid. The investigations carried out primarily concern the release behaviour of cerium and neodymium in the temperature region of 1200 to 1700 0 C. UO 2 + graphite, both in powder form, are selected as suitable reaction system having the preconditions needed for the lattice conversion for the release effect. The target aimed at from the practical aspect for the improved release of lanthanoids is achieved by an isobar test course - changing temperature from 1200 to 1500 0 C at constant pressure, with a cerium release of 75-80% and a neodynium release of 80-90% (maximum at 1400 0 C). The concepts on the mechanism of the fission product release are related to transport processes in crystal lattices, as well as chemical solid reactions and evaporation processes on the surface of UC 2 grains. (orig./RB) [de

  15. Erosional stability of rehabilitated uranium mine structures incorporating natural landform characteristics, northern tropical Australia

    International Nuclear Information System (INIS)

    East, T.J.; Uren, C.J.; Noller, B.N.; Cull, R.F.; Curley, P.M.; Unger, C.J.

    1994-01-01

    Australian Government guidelines specify that tailings containment structures at rehabilitated uranium mines in the Alligator Rivers Region of tropical northern Australia should have an engineered structural life of 1000 years. As part of the containment structure design process, erosion plots incorporating both regional geomorphological characteristics (concave hillslope profiles and a weathering-resistant rock cover of schist) and more conventional engineering design parameters (straight slopes and mine waste rock) were constructed at the Ranger Uranium Mine. The plots were monitored for storm runoff, and concentrations of solutes, suspended solids and selected ions over successive wet seasons. The concave slopes (the hillslope analogues) had lower peak discharges and lower concentrations of suspended solids than the straight slopes. However, solute concentrations in runoff from the schist covered (hillslope) slopes were higher than from the waste rock covered plots. Solute (mainly magnesium sulfate) concentrations for both rock types decreased by about an order of magnitude over the wet season. High sulfate concentrations are also likely to decrease substantially after several wet seasons, due to settlement of the waste rock and a reduction in rates of weathering. Development of a vegetation cover on the rehabilitated landforms will reduce the high suspended sediment concentrations. These initial results suggest that rehabilitated uranium mine structures which utilise selected features of stable natural landforms in their design may have greater erosional stability than more conventionally engineered structures. (orig.)

  16. Biogeochemical controls of uranium bioavailability from the dissolved phase in natural freshwaters

    Science.gov (United States)

    Croteau, Marie-Noele; Fuller, Christopher C.; Cain, Daniel J.; Campbell, Kate M.; Aiken, George R.

    2016-01-01

    To gain insights into the risks associated with uranium (U) mining and processing, we investigated the biogeochemical controls of U bioavailability in the model freshwater speciesLymnaea stagnalis (Gastropoda). Bioavailability of dissolved U(VI) was characterized in controlled laboratory experiments over a range of water hardness, pH, and in the presence of complexing ligands in the form of dissolved natural organic matter (DOM). Results show that dissolved U is bioavailable under all the geochemical conditions tested. Uranium uptake rates follow first order kinetics over a range encompassing most environmental concentrations. Uranium uptake rates in L. stagnalis ultimately demonstrate saturation uptake kinetics when exposure concentrations exceed 100 nM, suggesting uptake via a finite number of carriers or ion channels. The lack of a relationship between U uptake rate constants and Ca uptake rates suggest that U does not exclusively use Ca membrane transporters. In general, U bioavailability decreases with increasing pH, increasing Ca and Mg concentrations, and when DOM is present. Competing ions did not affect U uptake rates. Speciation modeling that includes formation constants for U ternary complexes reveals that the aqueous concentration of dicarbonato U species (UO2(CO3)2–2) best predicts U bioavailability to L. stagnalis, challenging the free-ion activity model postulate.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-11-01

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

  18. Natural Transmutation of Actinides via the Fission Reaction in the Closed Thorium-Uranium-Plutonium Fuel Cycle

    Science.gov (United States)

    Marshalkin, V. Ye.; Povyshev, V. M.

    2017-12-01

    It is shown for a closed thorium-uranium-plutonium fuel cycle that, upon processing of one metric ton of irradiated fuel after each four-year campaign, the radioactive wastes contain 54 kg of fission products, 0.8 kg of thorium, 0.10 kg of uranium isotopes, 0.005 kg of plutonium isotopes, 0.002 kg of neptunium, and "trace" amounts of americium and curium isotopes. This qualitatively simplifies the handling of high-level wastes in nuclear power engineering.

  19. The dose exposure of the environmental population by natural and released Ra-226 from an uranium mine prospect

    International Nuclear Information System (INIS)

    Schuettelkopf, H.; Kiefer, H.

    1980-08-01

    The concentration of natural Ra-226 in the environment of Baden-Baden was determined in samples of drinking water, surface water, sediments, soil, fish, milk and other food. The results partly are higher than normal caused by a local uranium deposit. Ra-226 releases with waste water from an uranium mine prospect are measured. The Ra-226 concentrations in creeks and sediments partly caused by this waste water were determined. Ra-226 concentrations in soil and plant samples collected on uranium ore dumps were partly much higher than in the environment. (orig.) [de

  20. Burn-Up Determination by High Resolution Gamma Spectrometry: Spectra from Slightly-Irradiated Uranium and Plutonium between 400-830 keV

    Energy Technology Data Exchange (ETDEWEB)

    Forsyth, R S; Ronqvist, N

    1966-08-15

    Previously published studies of the short-cooled fission product spectra of irradiated uranium have been severely restricted by the poor energy resolution of the sodium iodide detectors used. In this report are presented fission product spectra of irradiated uranium and plutonium obtained by means of a lithium-drifted germanium detector. The resolved gamma peaks have been assigned to various fission products by correlation of measured energy and half-life values with published data. By simultaneous study of the spectra of two irradiated mixtures of plutonium and uranium, the possibility of using the activities of Ru-103 and Ru-106 as a measure of the relative fission rate in U-235 and Pu-239 has been briefly examined.

  1. Burn-Up Determination by High Resolution Gamma Spectrometry: Spectra from Slightly-Irradiated Uranium and Plutonium between 400-830 keV

    International Nuclear Information System (INIS)

    Forsyth, R.S.; Ronqvist, N.

    1966-08-01

    Previously published studies of the short-cooled fission product spectra of irradiated uranium have been severely restricted by the poor energy resolution of the sodium iodide detectors used. In this report are presented fission product spectra of irradiated uranium and plutonium obtained by means of a lithium-drifted germanium detector. The resolved gamma peaks have been assigned to various fission products by correlation of measured energy and half-life values with published data. By simultaneous study of the spectra of two irradiated mixtures of plutonium and uranium, the possibility of using the activities of Ru-103 and Ru-106 as a measure of the relative fission rate in U-235 and Pu-239 has been briefly examined

  2. Linking AS, SE, V, and MN Behavior to Natural Biostimulated Uranium Cycling

    Energy Technology Data Exchange (ETDEWEB)

    Keimowitz, Alison [Vassar College, Poughkeepsie, NY (United States); Ranville, James [Colorado School of Mines, Golden, CO (United States); Mailloux, Brian [Barnard College, New York, NY (United States); Figueroa, Linda [Colorado School of Mines, Golden, CO (United States)

    2016-03-16

    The project “Linking As, Se, V, and Mn behavior to Natural and Biostimulated Uranium Cycling” successfully investigated Arsenic cycling the Rifle Colorado IFRC. This project trained undergraduate and graduate students at the Colorado School of Mines, Vassar College, and Barnard College. This resulted in both undergraduate theses and a PhD thesis and multiple publications. The science was highly successful and we were able to test the main hypotheses. We have shown that (H1) under reducing conditions that promote uranium immobilization arsenic is readily mobilized, that (H2) thioarsenic species are abundant during this mobilization, and (H3) we have examined arsenic mobilization for site sediment. At the Rifle IFRC Acetate was added during experiments to immobilize Uranium. These experiments successfully immobilized uranium but unfortunately would mobilize arsenic. We developed robust sampling and analysis methods for thioarsenic species. We showed that the mobilization occurred under sulfate reducing conditions and the majority of the arsenic was in the form of thioarsenic species. Previous studies had predicted the presence of thioarsenic species but this study used robust field and laboratory methods to quantitatively determine the presence of thioarsenic species. During stimulation in wells with high arsenic the primary species were trithioarsenate and dithioarsenate. In wells with low levels of arsenic release thioarsenates were absent or minor components. Fortunately after the injection of acetate ended the aquifer would become less reducing and the arsenic concentrations would decrease to pre-injection levels. In aquifers where organic carbon is being added as a remedial method or as a contaminant the transient mobility of arsenic during sulfidogenesis should be considered especially in sulfate rich aquifers as this could impact downgradient water quality.

  3. Effects of Electron Beam Irradiated Natural Casings on the Quality Characteristics of Emulsion Sausage

    International Nuclear Information System (INIS)

    Kim, Hyunwook; Kim, Hackyoun; Hwang, Koeun; Choi, Sunmi; Kim, Cheonjei; Choi, Jihun; Choi, Yunsang; Lee, Juwoon

    2011-01-01

    The effects of electron beam irradiated hog and sheep casings (1, 3, and 8 KGy) on the physicochemical properties and shelf stability of emulsion sausage were evaluated. There were no significantly differences in ph, instrumental color, and sensory evaluation among all the samples tested (p>0.05). The cooking yields for the irradiated treated samples were larger than the yields obtained for the non-irradiated samples for both the hog and sheep casing. However, the results on the purge loss after storage for 5 weeks were contradictory. The hardness of the sausage was lower when the irradiated natural casings were used. The irradiated natural casings accelerated lipid oxidation. The volatile basic nitrogen values were lower in samples treated with electron beam irradiation. The natural casings irradiated up to a dose of 3kGy not only had different total aerobic bacteria counts during the initial storage period but also displayed higher TAB counts at the final storage period

  4. Content of Natural Radionuclides in Sediments in the Vicinity of a Former Uranium Mine

    International Nuclear Information System (INIS)

    Strok, M.; Planinsek, P.; Smodis, B.

    2011-01-01

    Former Slovenian uranium mine Zirovski vrh lies in the subalpine environment with relative high rainfall and population density. As a legacy of uranium mining, Jazbec and Borst waste piles were constructed in the vicinity of a former uranium mine. On the Jazbec waste pile, about 2.5 millions of tons of spoil, and 0.05 millions of tons of red mud were deposited. Average activity concentrations in spoil are 750 Bq/kg for 238U, 226Ra and 230Th, and in red mud 495 Bq/kg for 238U, 190 Bq/kg for 226Ra and 65100 Bq/kg for 230Th. On the Borst waste pile, about 0.6 millions of tons of uranium mill tailings (UMT) were deposited. Average activity concentrations in UMT are 995 Bq/kg for 238U, 8630 Bq/kg for 226Ra and 3930 Bq/kg for 230Th. Seepage waters with elevated radionuclide concentrations from both waste piles flow in the nearby streams Brebovscica and Todrascica. Todrascica outfalls into the Brebovscica and Brebovscica into the Poljanska Sora River. Due to the different biogeochemical processes, natural radionuclides from both waste piles can be transferred to the sediments of the affected streams. These processes are mainly driven by the sorption onto the particles and particles settling or by the direct diffusion to sediments. Therefore the aim of this work was to find out at which extent these processes occur in the specific case by comparing activity concentrations in sediments before and after inflow of seepage waters from both waste piles. In sediment samples, 238U, 234U, 230Th, 226Ra, 210Pb and 210Po activity concentrations were determined, using radiochemical separations followed by either alpha spectrometry or proportional counting. Results of the content of natural radionuclides in sediments in the vicinity of a former uranium mine showed that activity concentrations of all analyzed radionuclides were higher in sediments after the inflow of seepage waters from waste piles in Brebovscica and Todrascica stream. This was not the case for Poljanska Sora River

  5. Radioactive decay properties of CANDU fuel. Volume 1: the natural uranium fuel cycle

    International Nuclear Information System (INIS)

    Clegg, L.J.; Coady, J.R.

    1977-01-01

    The two books of Volume 1 comprise the first in a three-volume series of compilations on the radioactive decay propertis of CANDU fuel and deal with the natural uranium fuel cycle. Succeeding volumes will deal with fuel cycles based on plutonium recycle and thorium. In Volume 1 which is divided into three parts, the computer code CANIGEN was used to obtain the mass, activity, decay heat and toxicity of CANDU fuel and its component isotopes. Data are also presented on gamma spectra and neutron emissions. Part 3 contains the data relating to the plutonium product and the high level wastes produced during fuel reprocessing. (author)

  6. Physics characteristics of a CANDU-600 with repositional adjuster rods fuelled with MOX or natural uranium

    International Nuclear Information System (INIS)

    Boczar, P.G.

    1985-06-01

    Repositioning the adjuster rods in 4 axial banks in future CANDU-600 reactors would permit the flexibility of grading the inner and outer banks to achieve optimal flattening of the axial power distribution for any particular fuel. With the 4 banks identical, acceptable axial power profiles can be achieved for both MOX and natural uranium fuels. Future work is to be directed at assessing the impact of lower zone controller and shutoff rod worth in the configuration of reactivity devices considered here, and if necessary, in identifying means of increasing their worth

  7. Selective extractions in uranium migration studies - Findings from a natural analogue study at Palmottu

    International Nuclear Information System (INIS)

    Suksi, J.; Saarinen, L.

    1994-01-01

    The usefulness of chemical extractions in the study on uranium migration is considered in the light of the results compiled at Palmottu. Chemical extractions provide a method for evaluating the mass transfer of U and its retardation in geochemical cycling. The present detailed study provides more specific information on the in situ fixation of U on rock materials. The many observations made at Palmottu show the potential of the method to fill the gap in interpretations between the natural partitioning of U in rock and the distribution of artificial tracers determined by the short-term laboratory experiments. (orig.) (20 refs., 4 figs., 1 tab.)

  8. Discharge Burnup Evaluation of Natural Uranium Loaded CANFLEX-43 Fuel Bundle

    International Nuclear Information System (INIS)

    Roh, Gyu Hong; Kim, Yong Hee; Kim, Won Young; Park, Joo Hwan

    2009-11-01

    Using WIMS-AECL code, which is 2-dimensional lattice core used in CANDU physics calculation, the discharge burnup of the natural uranium loaded CANFLEX-43 fuel bundle was evaluated by comparing the discharge burnup of standard 37 element fuel bundle. When the discharge burnup of the standard 37 element fuel is 7,200 MWd/MTU, that of the CANFLEX 43 fuel bundle was evaluated as 7,077 MWd/MTU, by applying the same lattice conditions for both fuel bundles

  9. Process for decontamination of surfaces in an facility of natural uranium hexafluoride production (UF6)

    International Nuclear Information System (INIS)

    Almeida, Claudio C. de; Silva, Teresinha M.; Rodrigues, Demerval L.; Carneiro, Janete C.G.G.

    2017-01-01

    The experience acquired in the actions taken during the decontamination process of an IPEN-CNEN / SP Nuclear and Energy Research Institute facility, for the purpose of making the site unrestricted, is reported. The steps of this operation involved: planning, training of facility operators, workplace analysis and radiometric measurements. The facility had several types of equipment from the natural uranium hexafluoride (UF 6 ) production tower and other facility materials. Rules for the transportation of radioactive materials were established, both inside and outside the facility and release of materials and installation

  10. The manufacturing of depleted uranium biological shield components

    International Nuclear Information System (INIS)

    Metelkin, J.A.

    1998-01-01

    The unique combination of the physical and mechanical properties of uranium made it possible to manufacture biological shield components of transport package container (TPC) for transportation nuclear power plant irradiated fuel and radionuclides of radiation diagnostic instruments. Protective properties are substantially dependent on the nature radionuclide composition of uranium, that why I recommended depleted uranium after radiation chemical processing. Depleted uranium biological shield (DUBS) has improved specific mass-size characteristics compared to a shield made of lead, steel or tungsten. Technological achievements in uranium casting and machining made it possible to manufacture DUBS components of TPC up to 3 tons of mass and up to 2 metres of the maximum size. (authors)

  11. Comparison of potential radiological consequences from a spent-fuel repository and natural uranium deposits

    International Nuclear Information System (INIS)

    Wick, O.J.; Cloninger, M.O.

    1980-09-01

    A general criterion has been suggested for deep geological repositories containing spent fuel - the repositories should impose no greater radiological risk than due to naturally occurring uranium deposits. The following analysis investigates the rationale of that suggestion and determines whether current expectations of spent-fuel repository performance are consistent with such a criterion. In this study, reference spent-fuel repositories were compared to natural uranium-ore deposits. Comparisons were based on intrinsic characteristics, such as radionuclide inventory, depth, proximity to aquifers, and regional distribution, and actual and potential radiological consequences that are now occurring from some ore deposits and that may eventually occur from repositories and other ore deposits. The comparison results show that the repositories are quite comparable to the natural ore deposits and, in some cases, present less radiological hazard than their natural counterparts. On the basis of the first comparison, placing spent fuel in a deep geologic repository apparently reduces the hazard from natural radioactive materials occurring in the earth's crust by locating the waste in impermeable strata without access to oxidizing conditions. On the basis of the second comparison, a repository constructed within reasonable constraints presents no greater hazard than a large ore deposit. It is recommended that if the naturally radioactive environment is to be used as a basis for a criterion regarding repositories, then this criterion should be carefully constructed. The criterion should be based on the radiological quality of the waters in the immediate region of a specific repository, and it should be in terms of an acceptable potential increase in the radiological content of those waters due to the existence of the repository

  12. The recovery of 99Mo from solutions of irradiated Uranium using a column with nanoparticles of Titanium Dioxide

    International Nuclear Information System (INIS)

    Androne, G. E.; Petre, M.; Lazar, C. G.

    2016-01-01

    Molyibdenum-99 (T½ = 66.02 h) decays by beta emission to 99 Tcm (T½ = 6.02 h). The latter nuclide is used in many nuclear medicine applications. The 99 Mo is produced from irradiated high (HEU) or low (LEU) enriched uranium. In this work a sensitive and selective method for recovering Mo from uranium solution, using a column with titanium dioxide nanoparticles, is developed. The titanium dioxide (TiO 2 ) nanoparticles were synthesized via sol-gel method using titanium tetra-chloride as starting material and urea as a reacting medium. A 40 ml uranium solution containing 450 g/L uranyl nitrate, 1 M HNO 3 , and 4 mg Mo was loaded on a column containing 6 g of TiO 2 sorbent at 75°C. After loading, the column was washed with 1 M HNO 3 and H 2 O. Mo was stripped from the column with 0.1 M NaOH at 25°C. The ICP-MS results indicate that 80-95% of the initial mass of Mo was loaded on the column, and 90-94% of this quantity was recovered in the strip fraction. (authors)

  13. Study of natural diamond detector spectrometric properties under neutron irradiation

    CERN Document Server

    Alekseyev, A B; Kaschuck, Y; Krasilnikov, A; Portnov, D; Tugarinov, S

    2002-01-01

    Natural diamond detector (NDD) performance was studied up to a neutron fluence of 10 sup 1 sup 5 neutron/cm sup 2. The variations of the NDD spectrometric response to incident alpha-particles from sup 2 sup 4 sup 1 Am source after exposure to fast neutron fluences up to 3x10 sup 1 sup 6 n/cm sup 2 were examined. No significant variations up to the level of 10 sup 1 sup 4 n/cm sup 2 were observed. Degradation of charge collection efficiency at higher fluences is reported. No remarkable increase of the NDD leakage current and count rate change had been observed up to a neutron fluence of 3x10 sup 1 sup 6 n/cm sup 2. The charge collection efficiency variations of neutron irradiated diamond spectrometer were studied ex situ under gamma-rays, beta-radiation and visible light excitation. Charge collection efficiency restoration up to 75% level and the NDD performance stabilization by extrinsic low-intensity visible light (550 nm

  14. Recovery of uranium from seawater. 14. System arrangements for the recovery of uranium from seawater by spherical amidoxime chelating resins utilizing natural seawater motions

    International Nuclear Information System (INIS)

    Egawa, Hiroaki; Kabay, Nalan; Shuto, Taketomi; Jyo, Akinori

    1993-01-01

    In order to evaluate performances of lightly cross-linked highly porous amidoxime resins in uranium-adsorption systems utilizing natural seawater motions, uranium uptake by the resins from seawater was studied by different approaches, such as simulated sea current exposure tests, towing trials, and/or mooring trials. In general, the efficiency of uranium uptake became higher with a decrease in the thickness of packing layers, indicating important roles of fluidization of the resin particles. On the basis of these fundamental data, mooring tests in the natural sea current were designed and conducted. By mooring flat adsorption beds (base area 260 cm 2 , height 3.0 cm) packed with 780 ml of the resin for 40 h, promising uranium uptake as high as 44 mg/kg of resin (9.9 mg/l of resin) was achieved under sea conditions in which the velocity of sea currents and the vertical velocity of waves were 5.5-49.7 cm/s and 3.4-27 cm/s, respectively

  15. The Palmottu Analogue Project, Progress Report 1993. The behaviour of natural radionuclides in and around uranium deposits, Nr. 7

    International Nuclear Information System (INIS)

    Ruskeeniemi, T.; Blomqvist, R.; Suksi, J.; Niini, H.

    1994-01-01

    The report gives a summary of the results of investigations carried out in 1993 at the Palmottu natural analogue study site, which comprises a small U-Th mineralization in Nummi-Pusula, southwestern Finland. Additionally, the report includes several separate articles dealing with various aspects of the Palmottu Analogue Project: (1) 3-dimensional model of fracture zones, (2) redox chemistry of uranium in groundwater, (3) humic substances in groundwater, (4) uranium mineralogy, (5) importance of selective extractions in uranium migration studies, (6) modelling of matrix diffusion, and (7) uranium in surficial deposits. The Palmottu Analogue Project aims at a more profound understanding of radionuclide transport processes in fractured crystalline bedrock. The essential factors controlling transport are groundwater flow and interaction between water and rock. Accordingly, the study includes (1) structural interpretations partly based on geophysical measurements, (2) hydrological studies including hydraulic drill-hole measurements, (3) flow modelling, (4) hydrogeochemical characterization of groundwater, uranium chemistry and colloid chemistry, (5) mineralogical studies, (6) geochemical interpretation and modelling, (7) studies on mobilization and retardation of uranium, and (8) modelling of uranium series data. Paleohydrogeological aspects are of special interest, due to the anticipated future glaciation of the Fennoscandian Shield. Surficial sediments and waters are studied to gain information on postglacial migration in the overburden. (orig.)

  16. Quality properties of sausage made with gamma irradiated natural casing from intestine of pork or lamb

    International Nuclear Information System (INIS)

    Jo, Cheorun; Lee, J.-W.; Cho, K.-H.; Yook, H.-S.; Byun, M.-W.

    2002-01-01

    Quality properties in emulsion-type sausage stuffed into irradiated natural casing were studied. The numbers of total aerobic bacteria, Enterococci and coliform bacteria in the sausage prepared with irradiated natural pork and lamb casing were significantly decreased or eliminated compared to those prepared with the nonirradiated control. The 2-thiobarbituric acid reactive substances (TBARS) value in the sausage with irradiated natural casing did not change significantly during storage with minor exceptions. The total working force of shear of the sausages were decreased in both irradiated casings but the sensory evaluation showed no difference. Therefore, the gamma irradiation was a useful technique to sanitize the natural pork and lamb casings and to extend the shelf-life of the sausage made with natural casings during distribution

  17. Quality properties of sausage made with gamma irradiated natural casing from intestine of pork or lamb

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Cheorun; Lee, J.-W.; Cho, K.-H.; Yook, H.-S.; Byun, M.-W. E-mail: mwbyun@kaeri.re.kr

    2002-03-01

    Quality properties in emulsion-type sausage stuffed into irradiated natural casing were studied. The numbers of total aerobic bacteria, Enterococci and coliform bacteria in the sausage prepared with irradiated natural pork and lamb casing were significantly decreased or eliminated compared to those prepared with the nonirradiated control. The 2-thiobarbituric acid reactive substances (TBARS) value in the sausage with irradiated natural casing did not change significantly during storage with minor exceptions. The total working force of shear of the sausages were decreased in both irradiated casings but the sensory evaluation showed no difference. Therefore, the gamma irradiation was a useful technique to sanitize the natural pork and lamb casings and to extend the shelf-life of the sausage made with natural casings during distribution.

  18. Natural radioactivity around a prospected uranium mining area in Finnish Lapland

    International Nuclear Information System (INIS)

    Rissanen, K.

    1983-01-01

    An environmental survey of natural radionuclides was carried out around the Pahtavuoma uranium occurrence site at Kittilae in Finnish Lapland. The aim of the survey was to determine the background levels of these nuclides in the terrestrial and aquatic ecosystems before changing the natural conditions by mining. All of the samples collected were analyzed for Ra-226 after radiochemical separation. Low Ra-226-content, < 0.02 - 1.9 Bg/kg d.w., was measured in locally produced foodstuffs, reindeer, elk and fish, cloudberry and blueberry; levels were 1.4 - 4.6 Bq/kg d.w. in cowberry. Contents of 0.3 - 5 Bq/kg were found in lichen, beard lichen, hay and fish bones, and higher concentrations in elk and reindeer bones (20 - 62 Bq/kg), aquatic plants Hippuris vulgaris (11 - 90 Bq/kg), and sediments (7 - 130 Bq/kg). The highest Ra-226 concentrations (110 - 3100 Bq/kg) were measured in aquatic mosses (Fontinalis sp). The Rn-222 and Ra-226-concentrations measured in surface and well waters were not higher than the average for Finland. Po-210 and Pb-210 determinations are in process. Dose rate and spectroscopic in situ measurements were performed as well. The results indicate lower environmental activity than the average for Lapland, except at the actual uranium mining site

  19. Natural Radioactivity in Soil and Water from Likuyu Village in the Neighborhood of Mkuju Uranium Deposit

    Directory of Open Access Journals (Sweden)

    Najat K. Mohammed

    2013-01-01

    Full Text Available The discovery of high concentration uranium deposit at Mkuju, southern part of Tanzania, has brought concern about the levels of natural radioactivity at villages in the neighborhood of the deposit. This study determined the radioactivity levels of 30 soil samples and 20 water samples from Likuyu village which is 54 km east of the uranium deposit. The concentrations of the natural radionuclides 238U, 232Th, and 40K were determined using low level gamma spectrometry of the Tanzania Atomic Energy Commission (TAEC Laboratory in Arusha. The average radioactivity concentrations obtained in soil samples for 238U (51.7 Bq/kg, 232Th (36.4 Bq/kg, and 40K (564.3 Bq/kg were higher than the worldwide average concentrations value of these radionuclides reported by UNSCEAR, 2000. The average activity concentration value of 238U (2.35 Bq/L and 232Th (1.85 Bq/L in water samples was similar and comparable to their mean concentrations in the control sample collected from Nduluma River in Arusha.

  20. Dyeing of γ-irradiated cotton with natural flavonoid dye extracted from irradiated onion shells (Allium cepa) powder

    International Nuclear Information System (INIS)

    Rehman, Fazal-ur; Adeel, Shahid; Shahid, Muhammad; Bhatti, Ijaz Ahmad; Nasir, Faiza; Akhtar, Nasim; Ahmad, Zulfiqar

    2013-01-01

    Powder of Onion shells as a source of natural flavonoid dye (Quercetin) and cotton fabrics were exposed to absorbed doses of 2, 4, 6, 8 and 10 kGy using Cs-137 gamma irradiator. Irradiated and un-irradiated dye powder was used for extraction of quercetin as well as antibacterial, hemolytic and antioxidant activities were also determined to observe the effect of radiation. Furthermore, color strength and colourfastness of irradiated fabrics were improved by using pre and post-mordants such as alum and iron. It is found that 4 kGy is the optimal absorbed dose for extraction of natural quercetin extracted from onion shells while maximum color strength and acceptable fastness properties are obtained on dyeing of irradiated fabric at 60 °C keeping M:L of 1:30 using 10% alum as pre-mordant and 6% alum as post-mordant. Gamma irradiation has not only improved the color strength of the dye using irradiated cotton but also that of colourfastness properties. - Highlights: • The optimal absorbed dose obtained for surface modification of cotton (RC) is 4 kGy. • The optimal absorbed dose for extraction of colorant from onion shell powder (RP) is 4 kGy. • Optimum dying conditions: 60 °C, 1 30 as M:L. • Optimum pre-mordant 10% alum and 6% alum as post-mordant. • At these optimum conditions: color strength and fastness properties are improved

  1. Dyeing of γ-irradiated cotton with natural flavonoid dye extracted from irradiated onion shells (Allium cepa) powder

    Science.gov (United States)

    Rehman, Fazal-ur; Adeel, Shahid; Shahid, Muhammad; Bhatti, Ijaz Ahmad; Nasir, Faiza; Akhtar, Nasim; Ahmad, Zulfiqar

    2013-11-01

    Powder of Onion shells as a source of natural flavonoid dye (Quercetin) and cotton fabrics were exposed to absorbed doses of 2, 4, 6, 8 and 10 kGy using Cs-137 gamma irradiator. Irradiated and un-irradiated dye powder was used for extraction of quercetin as well as antibacterial, hemolytic and antioxidant activities were also determined to observe the effect of radiation. Furthermore, color strength and colourfastness of irradiated fabrics were improved by using pre and post-mordants such as alum and iron. It is found that 4 kGy is the optimal absorbed dose for extraction of natural quercetin extracted from onion shells while maximum color strength and acceptable fastness properties are obtained on dyeing of irradiated fabric at 60 °C keeping M:L of 1:30 using 10% alum as pre-mordant and 6% alum as post-mordant. Gamma irradiation has not only improved the color strength of the dye using irradiated cotton but also that of colourfastness properties.

  2. Bioaccumulation and biological effects in the earthworm Eisenia fetida exposed to natural and depleted uranium

    Energy Technology Data Exchange (ETDEWEB)

    Giovanetti, Anna, E-mail: anna.giovanetti@enea.i [ENEA, Institute of Radiation Protection, CR Casaccia Via Anguillarese 301, 00123 Rome (Italy); Fesenko, Sergey [International Atomic Energy Agency (IAEA), Agency' s Laboratories Seibersdorf, A-2444 Seibersdorf (Austria); Cozzella, Maria L. [ENEA, National Institute for Metrology of Ionizing Radiation, CR Casaccia Via Anguillarese 301, 00123 Rome (Italy); Asencio, Lisbet D. [Centro de Estudios Ambientales, Carretera a Castillo de Jagua, CP. 59350 C. Nuclear, Cienfuegos (Cuba); Sansone, Umberto [International Atomic Energy Agency (IAEA), Agency' s Laboratories Seibersdorf, A-2444 Seibersdorf (Austria)

    2010-06-15

    The accumulations of both natural (U) and depleted (DU) uranium in the earthworms (Eisenia fetida) were studied to evaluate corresponding biological effects. Concentrations of metals in the experimental soil ranged from 1.86 to 600 mg kg{sup -1}. Five biological endpoints: mortality, animals' weight increasing, lysosomal membrane stability by measuring the neutral red retention time (the NRRT), histological changes and genetic effects (Comet assay) were used to evaluate biological effects in the earthworms after 7 and 28 days of exposure. No effects have been observed in terms of mortality or weight reduction. Cytotoxic and genetic effects were identified at quite low U concentrations. For some of these endpoints, in particular for genetic effects, the dose (U concentration)-effect relationships have been found to be non-linear. The results have also shown a statistically significant higher level of impact on the earthworms exposed to natural U compared to depleted U.

  3. Natural phenomena hazards evaluation of equipment and piping of Gaseous Diffusion Plant Uranium Enrichment Facility

    International Nuclear Information System (INIS)

    Singhal, M.K.; Kincaid, J.H.; Hammond, C.R.; Stockdale, B.I.; Walls, J.C.

    1995-01-01

    In support of the Gaseous Diffusion Plant Safety Analysis Report Upgrade program (GDP SARUP), a natural phenomena hazards evaluation was performed for the main process equipment and piping in the uranium enrichment buildings at Paducah and Portsmouth gaseous diffusion plants. In order to reduce the cost of rigorous analyses, the evaluation methodology utilized a graded approach based on an experience data base collected by SQUG/EPRI that contains information on the performance of industrial equipment and piping during past earthquakes. This method consisted of a screening walkthrough of the facility in combination with the use of engineering judgment and simple calculations. By using these screenings combined with evaluations that contain decreasing conservatism, reductions in the time and cost of the analyses were significant. A team of experienced seismic engineers who were trained in the use of the DOE SQUG/EPRI Walkdown Screening Material was essential to the success of this natural phenomena hazards evaluation

  4. Natural phenomena hazards evaluation of equipment and piping of Gaseous Diffusion Plant Uranium Enrichment Facility

    Energy Technology Data Exchange (ETDEWEB)

    Singhal, M.K.; Kincaid, J.H.; Hammond, C.R.; Stockdale, B.I.; Walls, J.C. [Oak Ridge National Lab., TN (United States). Technical Programs and Services; Brock, W.R.; Denton, D.R. [Lockheed Martin Energy Systems, Inc., Oak Ridge, TN (United States)

    1995-12-31

    In support of the Gaseous Diffusion Plant Safety Analysis Report Upgrade program (GDP SARUP), a natural phenomena hazards evaluation was performed for the main process equipment and piping in the uranium enrichment buildings at Paducah and Portsmouth gaseous diffusion plants. In order to reduce the cost of rigorous analyses, the evaluation methodology utilized a graded approach based on an experience data base collected by SQUG/EPRI that contains information on the performance of industrial equipment and piping during past earthquakes. This method consisted of a screening walkthrough of the facility in combination with the use of engineering judgment and simple calculations. By using these screenings combined with evaluations that contain decreasing conservatism, reductions in the time and cost of the analyses were significant. A team of experienced seismic engineers who were trained in the use of the DOE SQUG/EPRI Walkdown Screening Material was essential to the success of this natural phenomena hazards evaluation.

  5. Bioaccumulation and biological effects in the earthworm Eisenia fetida exposed to natural and depleted uranium

    International Nuclear Information System (INIS)

    Giovanetti, Anna; Fesenko, Sergey; Cozzella, Maria L.; Asencio, Lisbet D.; Sansone, Umberto

    2010-01-01

    The accumulations of both natural (U) and depleted (DU) uranium in the earthworms (Eisenia fetida) were studied to evaluate corresponding biological effects. Concentrations of metals in the experimental soil ranged from 1.86 to 600 mg kg -1 . Five biological endpoints: mortality, animals' weight increasing, lysosomal membrane stability by measuring the neutral red retention time (the NRRT), histological changes and genetic effects (Comet assay) were used to evaluate biological effects in the earthworms after 7 and 28 days of exposure. No effects have been observed in terms of mortality or weight reduction. Cytotoxic and genetic effects were identified at quite low U concentrations. For some of these endpoints, in particular for genetic effects, the dose (U concentration)-effect relationships have been found to be non-linear. The results have also shown a statistically significant higher level of impact on the earthworms exposed to natural U compared to depleted U.

  6. Influence of uranium and thorium in the natural radioactivity in shales from the middle Amazon river region

    International Nuclear Information System (INIS)

    Ferro, A.L.

    1982-02-01

    The feasibility of using the fission track registration technique in the determination of the uranium and thorium content in shales from the middle Amazon river region is studied. The above technique permits, through the determination of the uranium concentration, to establish a correlation between the uranium content and the organic matter present in the shale. In establishing the ratio between the fission tracks due to 238 U and 235 U, the sample was contaminated with natural uranium and analized, so that no modifications on the analysis conditions might change or distort the results. The experimental results were satisfactory and they may contribute to the study of the industrial exploration of these energy sources as well as to the analysis of problems related to environmental control. (Author) [pt

  7. The Palmottu natural analogue project. Progress report 1995. The behaviour of natural radionuclides in and around uranium deposits, Nr. 9

    International Nuclear Information System (INIS)

    Ruskeeniemi, T.; Blomqvist, R.

    1996-01-01

    Natural analogue studies at Palmottu (in Finland) have concentrated on characterising the general geological, hydrogeological and radiochemical setting of the uranium mineralisation. Since 1992 a research program focusing on the hydrogeological characterisation of potential flow routes has been in progress, and the basis for a constrained flow system has already been identified. Sophisticated studies have also been performed on groundwater redox chemistry and matrix diffusion processes. The report consists of an introduction to the activities carried out in 1995 followed by topical summaries documented by the principal investigators in charge of each activity. The following summaries are included in the report (1) Hydrogeological studies at Palmottu, (2) Modelling of groundwater flow, (3) TV-logging of boreholes, (4) Mineralogical and petrological studies, (5) Radionuclide migration studies and (6) Humic substances. Full technical and scientific results are documented in appropriate topical reports and publications referred to in this Progress Report. (46 refs., 10 figs., 4 tabs.)

  8. Natural uranium toxicology - evaluation of internal contamination in man; Toxicologie de l'uranium naturel - essai d'evaluation de la contamination interne chez l'homme

    Energy Technology Data Exchange (ETDEWEB)

    Chalabreysse, J [Commissariat a l' Energie Atomique, Pierrelatte (France). Centre d' Etudes Nucleaires

    1968-07-01

    After reminding the physical and chemical properties of natural uranium which might affect its toxicology, a comprehensive investigation upon natural uranium metabolism and toxicity and after applying occupational exposure standards to this particular poison, it has been determined, from accident reports and human experience reported in the related literature, a series of formulae obtained by theoretical mathematical development giving principles for internal contamination monitoring and disclosure by determining uranium in the urine of occupationally exposed individuals. An assay is performed to determine individual internal contamination according to the various contamination cases. The outlined purposes, mainly practical, required some options and extrapolations. The proposed formula allows a preliminary approach and also to determine shortly a contamination extent or to discuss the systematical urinalysis results as compared with individual radio-toxicology monitoring professional standards. (author) [French] Apres le rappel des caracteristiques physiques et des proprietes chimiques de l'uranium naturel pouvant avoir une influence sur sa toxicologie, l'etude detaillee de son metabolisme et de sa toxicite, puis l'application des normes professionnelles d'exposition au cas particulier de ce toxique, il est etabli, a partir des comptes rendus d'accidents et de l'experimentation humaine rapportes dans la litterature, une serie de formules obtenues par developpement mathematique theorique qui posent les principes de la surveillance et de la mise en evidence de la contamination interne par la recherche et le dosage de l'uranium dans les urines d'individus professionnellement exposes. Un essai d'evaluation de la contamination interne individuelle suivant les differents cas de contamination est effectue. Le formulaire propose permet de faire une premiere approximation et d'apprecier rapidement l'importance d'une contamination ou bien d'interpreter les resultats d

  9. Uranium Bio-accumulation and Cycling as revealed by Uranium Isotopes in Naturally Reduced Sediments from the Upper Colorado River Basin

    Science.gov (United States)

    Lefebvre, Pierre; Noël, Vincent; Jemison, Noah; Weaver, Karrie; Bargar, John; Maher, Kate

    2016-04-01

    Uranium (U) groundwater contamination following oxidized U(VI) releases from weathering of mine tailings is a major concern at numerous sites across the Upper Colorado River Basin (CRB), USA. Uranium(IV)-bearing solids accumulated within naturally reduced zones (NRZs) characterized by elevated organic carbon and iron sulfide compounds. Subsequent re-oxidation of U(IV)solid to U(VI)aqueous then controls the release to groundwater and surface water, resulting in plume persistence and raising public health concerns. Thus, understanding the extent of uranium oxidation and reduction within NRZs is critical for assessing the persistence of the groundwater contamination. In this study, we measured solid-phase uranium isotope fractionation (δ238/235U) of sedimentary core samples from four study sites (Shiprock, NM, Grand Junction, Rifle and Naturita, CO) using a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS). We observe a strong correlation between U accumulation and the extent of isotopic fractionation, with Δ238U up to +1.8 ‰ between uranium-enriched and low concentration zones. The enrichment in the heavy isotopes within the NRZs appears to be especially important in the vadose zone, which is subject to variations in water table depth. According to previous studies, this isotopic signature is consistent with biotic reduction processes associated with metal-reducing bacteria. Positive correlations between the amount of iron sulfides and the accumulation of reduced uranium underline the importance of sulfate-reducing conditions for U(IV) retention. Furthermore, the positive fractionation associated with U reduction observed across all sites despite some variations in magnitude due to site characteristics, shows a regional trend across the Colorado River Basin. The maximum extent of 238U enrichment observed in the NRZ proximal to the water table further suggests that the redox cycling of uranium, with net release of U(VI) to the groundwater by

  10. Assay of uranium in fused salt cake generated at the natural uranium metal fuel fabrication plants by gamma-ray spectrometry

    International Nuclear Information System (INIS)

    Kalsi, P.C.; Bhanu, A.U.; Sahoo, S.; Iyer, R.H.

    1986-01-01

    A passive gamma-ray spectroscopic method is employed for the assay of uranium in fused salt cake, a scrap produced at the natural uranium metal fuel fabrication plants. The method makes use of NaI(TI) detector coupled with a multichannel analyser. The 1 MeV gamma-ray of 238 U was used for the calibration. The calibration curve was made by counting synthetic mixtures made of U 3 O 8 powder, the heat treatment salt and iron in the form of fine powder. The uranium content in these synthetic mixtures was kept in the range of 1-11 per cent. 23 lots of the fused salt cake taken from three different batches of the salt cake were then analysed by this method. The uranium content of fused salt cake was found to be in the range of 1.70-11.43 per cent. To compare the gamma spectrometric results with a completely independent method, chemical analysis of all the fused salt cakes were also carried out. The NDA results were found to agree within ± 17 per cent with the chemical analysis results. (author)

  11. Tetra- and hexavalent uranium forms bidentate-mononuclear complexes with particulate organic matter in a naturally uranium-enriched peatland

    International Nuclear Information System (INIS)

    Mikutta, Christian; Langner, Peggy; Bargar, John R.; Kretzschmar, Ruben

    2016-01-01

    Peatlands frequently serve as efficient biogeochemical traps for U. Mechanisms of U immobilization in these organic matter-dominated environments may encompass the precipitation of U-bearing mineral(oid)s and the complexation of U by a vast range of (in)organic surfaces. The objective of this work was to investigate the spatial distribution and molecular binding mechanisms of U in soils of an alpine minerotrophic peatland (pH 4.7–6.6, E_h = –127 to 463 mV) using microfocused X-ray fluorescence spectrometry and bulk and microfocused U L_3-edge X-ray absorption spectroscopy. The soils contained 2.3–47.4 wt % organic C, 4.1–58.6 g/kg Fe, and up to 335 mg/kg geogenic U. Uranium was found to be heterogeneously distributed at the micrometer scale and enriched as both U(IV) and U(VI) on fibrous and woody plant debris (48 ± 10% U(IV), x̄ ± σ, n = 22). Bulk U X-ray absorption near edge structure (XANES) spectroscopy revealed that in all samples U(IV) comprised 35–68% of total U (x̄ = 50%, n = 15). Shell-fit analyses of bulk U L_3-edge extended X-ray absorption fine structure (EXAFS) spectra showed that U was coordinated to 1.3 ± 0.2 C atoms at a distance of 2.91 ± 0.01 Å (x̄ ± σ), which implies the formation of bidentate-mononuclear U(IV/VI) complexes with carboxyl groups. We neither found evidence for U shells at ~3.9 Å, indicative of mineral-associated U or multinuclear U(IV) species, nor for a substantial P/Fe coordination of U. As a result, our data indicates that U(IV/VI) complexation by natural organic matter prevents the precipitation of U minerals as well as U complexation by Fe/Mn phases at our field site, and suggests that organically complexed U(IV) is formed via reduction of organic matter-bound U(VI).

  12. Tetra- and Hexavalent Uranium Forms Bidentate-Mononuclear Complexes with Particulate Organic Matter in a Naturally Uranium-Enriched Peatland.

    Science.gov (United States)

    Mikutta, Christian; Langner, Peggy; Bargar, John R; Kretzschmar, Ruben

    2016-10-04

    Peatlands frequently serve as efficient biogeochemical traps for U. Mechanisms of U immobilization in these organic matter-dominated environments may encompass the precipitation of U-bearing mineral(oid)s and the complexation of U by a vast range of (in)organic surfaces. The objective of this work was to investigate the spatial distribution and molecular binding mechanisms of U in soils of an alpine minerotrophic peatland (pH 4.7-6.6, E h = -127 to 463 mV) using microfocused X-ray fluorescence spectrometry and bulk and microfocused U L 3 -edge X-ray absorption spectroscopy. The soils contained 2.3-47.4 wt % organic C, 4.1-58.6 g/kg Fe, and up to 335 mg/kg geogenic U. Uranium was found to be heterogeneously distributed at the micrometer scale and enriched as both U(IV) and U(VI) on fibrous and woody plant debris (48 ± 10% U(IV), x̅ ± σ, n = 22). Bulk U X-ray absorption near edge structure (XANES) spectroscopy revealed that in all samples U(IV) comprised 35-68% of total U (x̅ = 50%, n = 15). Shell-fit analyses of bulk U L 3 -edge extended X-ray absorption fine structure (EXAFS) spectra showed that U was coordinated to 1.3 ± 0.2 C atoms at a distance of 2.91 ± 0.01 Å (x̅ ± σ), which implies the formation of bidentate-mononuclear U(IV/VI) complexes with carboxyl groups. We neither found evidence for U shells at ∼3.9 Å, indicative of mineral-associated U or multinuclear U(IV) species, nor for a substantial P/Fe coordination of U. Our data indicates that U(IV/VI) complexation by natural organic matter prevents the precipitation of U minerals as well as U complexation by Fe/Mn phases at our field site, and suggests that organically complexed U(IV) is formed via reduction of organic matter-bound U(VI).

  13. Chapter 3: Exponential experiments on graphite-moderated lattices fuelled with near-natural uranium metal rods

    International Nuclear Information System (INIS)

    McCulloch, D.B.; Clarke, W.G.; Ashworth, F.P.O.; Hoskins, T.A.

    1963-01-01

    Exponential experiments have been carried out on graphite lattices fuelled by 1.2 in. diameter uranium metal rods at three near-natural U 235 compositions, 0.6 Co, 1.3 Co and 1.6 Co. The results, together with those already existing from earlier exponential or critical measurements on these and similar natural uranium rods, have been correlated with the theory of Syrett (1961) and also with the modified form of this theory given in Vol.1, Ch. 7. (author)

  14. 133Xe release during post-irradiation annealing of uranium metal in the presence of a constant volume of air Pt. 1

    International Nuclear Information System (INIS)

    Marei, S.A.; El-Garhy, M.; El-Bayoumy, S.; Muenze, R.; Hladik, O.

    1978-01-01

    The fractional release of 133 Xe at different temperatures was studied as a function of time in the presence of air during post-irradiation annealing of uranium metal. The relation between the fractional release and tsup(1/2) was found to be irregular. There is an initial step in the annealing curves (at the temperature range of 400-710 deg C) which decreases by increasing temperature and totally disappears at the high temperature of 800-1000 deg C. The initial step was found to be due to the surface oxidation of uranium metal. The other two parts of the release curves are normal for 133 Xe release from uranium metal. Since in this work the irradiation temperature is low ( 133 Xe. (T.G.)

  15. The text of the Agreement of 1 July 1983 concerning the Agency's assistance to Romania for the transfer of enriched uranium for irradiation studies in a research reactor

    International Nuclear Information System (INIS)

    1983-12-01

    The full text of the Supply and Project Agreement of 1 July 1983 between the Agency and the Government of the Socialist Republic of Romania concerning the Agency's assistance for the transfer of moderately enriched uranium from the USSR for irradiation studies in a research reactor in Romania is presented

  16. Enhanced CANDU6: Reactor and fuel cycle options - Natural uranium and beyond

    International Nuclear Information System (INIS)

    Ovanes, M.; Chan, P. S. W.; Mao, J.; Alderson, N.; Hopwood, J. M.

    2012-01-01

    The Enhanced CANDU 6 R (ECo R ) is the updated version of the well established CANDU 6 family of units incorporating improved safety characteristics designed to meet or exceed Generation III nuclear power plant expectations. The EC6 retains the excellent neutron economy and fuel cycle flexibility that are inherent in the CANDU reactor design. The reference design is based on natural uranium fuel, but the EC6 is also able to utilize additional fuel options, including the use of Recovered Uranium (RU) and Thorium based fuels, without requiring major hardware upgrades to the existing control and safety systems. This paper outlines the major changes in the EC6 core design from the existing C6 design that significantly enhance the safety characteristics and operating efficiency of the reactor. The use of RU fuel as a transparent replacement fuel for the standard 37-el NU fuel, and several RU based advanced fuel designs that give significant improvements in fuel burnup and inherent safety characteristics are also discussed in the paper. In addition, the suitability of the EC6 to use MOX and related Pu-based fuels will also be discussed. (authors)

  17. Radon as a natural tracer for gas transport within uranium waste rock piles

    International Nuclear Information System (INIS)

    Silva, N.C.; Chagas, E.G.L.; Dias, D.C.S.; Guerreiro, E.T.Z.; Alberti, H.L.C.; Braz, M.L.; Abreu, C.B.; Lopez, D.; Branco, O.; Fleming, P.

    2014-01-01

    Acid mine drainage (AMD) has been identified as the main cause for outflow of acid water and radioactive/non-radioactive contaminants. AMD encompasses pyrites oxidation when water and oxygen are available. AMD was identified in uranium waste rock piles (WRPs) of Industrias Nucleares do Brasil-Caldas facility (Brazilian uranium mine), resulting in high costs for water treatment. AMD reduction is the main challenge, and scientific investigation has been conducted to understand oxygen and water transportation within WRPs, where 222 Rn is used as natural tracer for oxygen transportation. The study consists of soil radon gas mapping in the top layer of WRP4 using active soil gas pumping, radon adsorption in active charcoal and 222 Rn determination using high-resolution gamma-ray spectrometry. A sampling network of 71 points was built where samples were collected at a depth of 40 cm. Soil radon gas concentration ranged from 33.7 to 1484.2 kBq m -3 with mean concentration of 320.7±263.3 kBq m -3 . (authors)

  18. Treatment of acid drainage in uranium deposit by means of a natural wetland

    International Nuclear Information System (INIS)

    Grudeva, V.I.; Stoyanova, A.D.; Grudev, S.N.

    2004-01-01

    Acid drainage waters generated in the uranium deposit G-1, Western Bulgaria, were treated by means of a natural wetland located in the deposit. The waters had a pH in the range of about 2.4-3.9 and contained uranium and radium radionuclides, heavy metals (copper, zinc , cadmium, iron, manganese) arsenic and sulfates in concentrations usually much higher than the relevant permissible levels for waters intended for use in agriculture and/or industry. The wetland was characterized by abundant and emergent vegetation and a diverse microflora. Typha latifolia, Typha augustifolia and Potamogeton australis were the main plant species in the wetland but representatives of the genera Scirpus, Juncus, Elepchoris, Potamogeton, Carex and Poa as well as different algae were also present. The water flows through the wetland varied in the range at about 0.2-1,2 l/s reflecting water residence times in the wetland of about 10-50 hours. An efficient water cleanup took place in the wetland even during the cold winter months at ambient temperatures close to 0 o C. The removal of pollutants was due to different processes but the microbial dissimilatory sulphate reduction and the sorption of pollutants on organic matter (living and dead plant and microbial biomass) and clays present in the wetland played the main role. (author)

  19. Limitation of population's irradiation by natural sources of ionizing radiation

    International Nuclear Information System (INIS)

    Krisyuk, Eh.M.

    1989-01-01

    Review of works devoted to evaluating the human irradiation doses at the expense of the main sources of ionizing radiation, is given. It is shown that the human irradiation doses at the expense of DDP can be reduced 10 times and more. However to realize such measures it is necessary to study the efficiency and determine the cost of various protective activities as well as to develop the criteria of their realization necessity

  20. Interpretation of uranium and thorium excretion data taking into account excretion data caused by natural sources

    International Nuclear Information System (INIS)

    Sahre, P.; Schoenmuth, Th.; Helling, K.

    2000-01-01

    At the Nuclear Engineering and Analytics Inc. Rossendorf near Dresden (Germany) occupationally exposed persons are working with Uranium and Thorium. In accordance with German guides urine and faecal analysis is carried out. But for the interpretation the data in terms of dose or intake it is important to have knowledge about the portion of the activity measured caused by natural sources. For this reason 16 occupationally exposed persons who did not have any history of occupational exposure to Thorium or Uranium have been checked concerning the excretion data since 1994. The excretion data in mBq per day for all persons covers the following ranges: Faeces: U-234 1 to 310 mBq/d, U-235 0.2 to 3.7 mBq/d, U-238 1.3 to 72 mBq/d. Th-228 7 to 89 mBq/d, Th-230 0.7 to 19 mBq/d, Th-232 0.7 to 16 mBq/d. Urine: all values below the detection limits of about 1 mBq/l. The large variation results from differences between the individual excretion rates but also from the variation of the excretion rate of one person. For example, the U-234-faecal excretion of one person reaches from 77 to 310 mBq per day. In the paper the faecal excretion for some individuals in dependence on the time are given. These excretion date caused by natural sources are taken into account by interpreting faecal excretion data of occupationally exposed persons working with Uranium or Thorium. If the measured faecal excretion per day is within the range caused by natural sources no interpretation will be done. By exceeding these values additional faeces and urine samples will be collected and measured. In dependence on these additional results intake and dose will be assessed some times by using lung counter or whole body counter measuring results. In the paper some examples are described. (author)

  1. Study and simulation of the behaviour under irradiation of helium in uranium dioxide; Etude et modelisation du comportement sous irradiation de l'helium dans le dioxyde d'uranium

    Energy Technology Data Exchange (ETDEWEB)

    Martin, G

    2007-06-15

    Large quantities of helium are produced from {alpha}-decay of actinides in nuclear fuels during its in-pile operating and its storage. It is important to understand the behaviour of helium in these matrix in order to well simulate the evolution and the resistance of the fuel element. During this thesis, we have used nuclear reaction analyses (NRA) to follow the evolution of the helium implanted in polycrystalline and monocrystalline uranium dioxide (UO{sub 2}). An experimental rig was developed to follow the on-line helium release in UO{sub 2} and the evolution of {sup 3}He profiles as a function of annealing temperature. An automated procedure taking into account the evolution of the depth resolution was developed. Analyses performed with a nuclear microprobe allowed to characterise the spatial distribution of helium at the grain scale and to study the influence of the sample microstructure on the helium migration. This work put into evidence the particular role of grain boundaries and irradiation defects in the helium release process. The analyse of experimental results with a diffusion model corroborates these interpretations. It allowed to determine quantitatively physical properties that characterise the helium behaviour in uranium dioxide (diffusion coefficient, activation energy..). (author)

  2. An extraction method of uranium 233 from the thorium irradiates in a reactor core

    International Nuclear Information System (INIS)

    Chesne, A.; Regnaut, P.

    1955-01-01

    Description of the conditions of separation of the thorium, of the uranium 233 and of the protactinium 233 in hydrochloric solution by absorption then selective elution on anion exchange resin. A precipitation of the thorium by the oxalic acid permits the recuperation of the hydrochloric acid which is recycled, the main, raw material consumed being the oxalic acid. (authors) [fr

  3. Uranium occurence in nature: Geophysical prospecting, and its occurence in Syria

    International Nuclear Information System (INIS)

    Al-Haj Rasheed, Zaki

    1985-01-01

    A general idea about naturaly occured uranium minerals such as uranite, pechblende, carnotite, coffinit, and bronnerit is given. At the same time, different geophysical methods and detecting devices applied for uranium exploration have been demonstrated. Investigations and studies carried out in Syria point to a uranium content of 100 ppm in the exploited Syrian phosphorite. 1 fig., 1 tab

  4. Processing of irradiated, enriched uranium fuels at the Savannah River Plant

    Energy Technology Data Exchange (ETDEWEB)

    Hyder, M L; Perkins, W C; Thompson, M C; Burney, G A; Russell, E R; Holcomb, H P; Landon, L F

    1979-04-01

    Uranium fuels containing /sup 235/U at enrichments from 1.1% to 94% are processed and recovered, along with neptunium and plutonium byproducts. The fuels to be processed are dissolved in nitric acid. Aluminum-clad fuels are disssolved using a mercury catalyst to give a solution rich in aluminum. Fuels clad in more resistant materials are dissolved in an electrolytic dissolver. The resulting solutions are subjected to head-end treatment, including clarification and adjustment of acid and uranium concentration before being fed to solvent extraction. Uranium, neptunium, and plutonium are separated from fission products and from one another by multistage countercurrent solvent extraction with dilute tri-n-butyl phosphate in kerosene. Nitric acid is used as the salting agent in addition to aluminum or other metal nitrates present in the feed solution. Nuclear safety is maintained through conservative process design and the use of monitoring devices as secondary controls. The enriched uranium is recovered as a dilute solution and shipped off-site for further processing. Neptunium is concentrated and sent to HB-Line for recovery from solution. The relatively small quantities of plutonium present are normally discarded in aqueous waste, unless the content of /sup 238/Pu is high enough to make its recovery desirable. Most of the /sup 238/Pu can be recovered by batch extraction of the waste solution, purified by counter-current solvent extraction, and converted to oxide in HB-Line. By modifying the flowsheet, /sup 239/Pu can be recovered from low-enriched uranium in the extraction cycle; neptunium is then not recovered. The solvent is subjected to an alkaline wash before reuse to remove degraded solvent and fission products. The aqueous waste is concentrated and partially deacidified by evaporation before being neutralized and sent to the waste tanks; nitric acid from the overheads is recovered for reuse.

  5. Processing of irradiated, enriched uranium fuels at the Savannah River Plant

    International Nuclear Information System (INIS)

    Hyder, M.L.; Perkins, W.C.; Thompson, M.C.; Burney, G.A.; Russell, E.R.; Holcomb, H.P.; Landon, L.F.

    1979-04-01

    Uranium fuels containing 235 U at enrichments from 1.1% to 94% are processed and recovered, along with neptunium and plutonium byproducts. The fuels to be processed are dissolved in nitric acid. Aluminum-clad fuels are disssolved using a mercury catalyst to give a solution rich in aluminum. Fuels clad in more resistant materials are dissolved in an electrolytic dissolver. The resulting solutions are subjected to head-end treatment, including clarification and adjustment of acid and uranium concentration before being fed to solvent extraction. Uranium, neptunium, and plutonium are separated from fission products and from one another by multistage countercurrent solvent extraction with dilute tri-n-butyl phosphate in kerosene. Nitric acid is used as the salting agent in addition to aluminum or other metal nitrates present in the feed solution. Nuclear safety is maintained through conservative process design and the use of monitoring devices as secondary controls. The enriched uranium is recovered as a dilute solution and shipped off-site for further processing. Neptunium is concentrated and sent to HB-Line for recovery from solution. The relatively small quantities of plutonium present are normally discarded in aqueous waste, unless the content of 238 Pu is high enough to make its recovery desirable. Most of the 238 Pu can be recovered by batch extraction of the waste solution, purified by counter-current solvent extraction, and converted to oxide in HB-Line. By modifying the flowsheet, 239 Pu can be recovered from low-enriched uranium in the extraction cycle; neptunium is then not recovered. The solvent is subjected to an alkaline wash before reuse to remove degraded solvent and fission products. The aqueous waste is concentrated and partially deacidified by evaporation before being neutralized and sent to the waste tanks; nitric acid from the overheads is recovered for reuse

  6. National acquisition of sufficient know-how to determine procurement of natural and enriched uranium

    International Nuclear Information System (INIS)

    Peix, J.; Rougeau, J.-P.

    1977-01-01

    Today, the guarantees of a natural uranium supply and of its enrichment, seem to be the necessary conditions for assuring the development of nuclear electric program. However, decisions cannot be made before further consideration of the consequences it will have on the whole service of the nuclear fuel cycle. Whether the supplies are immediate, or medium term, or long term, the lead-times of the fuel cycle and the present situation of the world energy supplies are such that a country committed to develop nuclear electric energy must equip itself quickly with the indispensable human potential to define its own supply policy and then, to assure a strict achievement up to its interests. Thus, without forecasting any sort of policy, the first matter is to study the problems arising from nuclear fuel cycle and to propose a minimal human and technical potential, indicating the different stages of its constitution. (author)

  7. Reference values and their application to the monitoring of occupational exposure to natural uranium compounds

    International Nuclear Information System (INIS)

    1986-09-01

    Natural uranium compounds, which enter the oxide fuel cycle offer physico-chemical characteristics dependent on their structure and their production process. These characteristics govern their biological behaviour and the degree of their radioactive and chemical toxicity. The monitoring of workers occupationnally exposed to these compounds is carried out by bioassays; in order to get the best interpretation, the resulting data must be compared to reference values. These values must be closely related to the type of contaminant and the real exposure conditions. In this report, the occupational medicine services working group has examined the possibilities of obtaining such reference values and suggests recommendations and operational values covering most situations found in routine monitoring [fr

  8. Gold wetting effects on sapphire irradiated with GeV uranium ions

    International Nuclear Information System (INIS)

    Ramos, S.M.M.

    1997-01-01

    Single crystals of α-Al 2 O 3 were irradiated with 238 U ions using two different energies: 3.4 MeV/u and 1.7 MeV/u. The irradiations were performed at a temperature of ∼80 K, with fluences ranging from 1.2 x 10 12 to 2.5 x 10 12 ions cm -2 . After irradiation, thin gold films were deposited on the sapphire surfaces by using a sputtering method. Subsequent annealing in air at a temperature of 723 and 923 K were applied to investigate the influence of the pre-damage on the adhesion of the gold layer on the sapphire surface. Rutherford backscattering analysis and scanning electron microscopy performed in both virgin and irradiated areas, show that the pre-irradiation damage inhibits the gold film of breaking up into islands after annealing. A wetting effect, which could depend on the damage morphology, is clearly observed. (orig.)

  9. Naturally Occurring Radioactive Materials in Uranium-Rich Coals and Associated Coal Combustion Residues from China.

    Science.gov (United States)

    Lauer, Nancy; Vengosh, Avner; Dai, Shifeng

    2017-11-21

    Most coals in China have uranium concentrations up to 3 ppm, yet several coal deposits are known to be enriched in uranium. Naturally occurring radioactive materials (NORM) in these U-rich coals and associated coal combustion residues (CCRs) have not been well characterized. Here we measure NORM (Th, U, 228 Ra, 226 Ra, and 210 Pb) in coals from eight U-rich coal deposits in China and the associated CCRs from one of these deposits. We compared NORM in these U-rich coals and associated CCRs to CCRs collected from the Beijing area and natural loess sediments from northeastern China. We found elevated U concentrations (up to 476 ppm) that correspond to low 232 Th/ 238 U and 228 Ra/ 226 Ra activity ratios (≪1) in the coal samples. 226 Ra and 228 Ra activities correlate with 238 U and 232 Th activities, respectively, and 226 Ra activities correlate well with 210 Pb activities across all coal samples. We used measured NORM activities and ash yields in coals to model the activities of CCRs from all U-rich coals analyzed in this study. The activities of measured and modeled CCRs derived from U-rich coals exceed the standards for radiation in building materials, particularly for CCRs originating from coals with U > 10 ppm. Since beneficial use of high-U Chinese CCRs in building materials is not a suitable option, careful consideration needs to be taken to limit potential air and water contamination upon disposal of U- and Ra-rich CCRs.

  10. Heat treatments of irradiated uranium oxide in a pressurised water reactor (P.W.R.): swelling and fission gas release

    International Nuclear Information System (INIS)

    Zacharie, I.

    1997-01-01

    In order to keep pressurised water reactors at a top level of safety, it is necessary to understand the chemical and mechanical interaction between the cladding and the fuel pellet due to a temperature increase during a rapid change in reactor. In this process, the swelling of uranium oxide plays an important role. It comes from a bubble precipitation of fission gases which are released when they are in contact with the outside. Therefore, the aim of this thesis consists in acquiring a better understanding of the mechanisms which come into play. Uranium oxide samples, from a two cycles irradiated fuel, first have been thermal treated between 1000 deg C and 1700 deg C for 5 minutes to ten hours. The gas release amount related to time has been measured for each treatment. The comparison of the experimental results with a numerical model has proved satisfactory: it seems that the gases release, after the formation of intergranular tunnels, is controlled by the diffusion phenomena. Afterwards, the swelling was measured on the samples. The microscopic examination shows that the bubbles are located in the grain boundaries and have a lenticular shape. The swelling can be explained by the bubbles coalescence and a model was developed based on this observation. An equation allows to calculate the intergranular swelling in function of time and temperature. The study gives the opportunity to predict the fission gases behaviour during a fuel temperature increase. (author)

  11. The Palmottu natural analogue project. The behaviour of natural radionuclides in and around uranium deposits. Summary report 1992-1994

    Energy Technology Data Exchange (ETDEWEB)

    Blomqvist, R; Ruskeeniemi, T; Ahonen, L [Geological Survey of Finland, Espoo (Finland); Suksi, J [Helsinki Univ. (Finland). Lab. of Radiochemistry; Niini, H [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Engineering Geology and Geophysics; Vuorinen, U [VTT Chemical Technology, Espoo (Finland); Jakobsson, K [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland)

    1995-06-01

    The Palmottu U-Th mineralization at Nummi-Pusula, southwestern Finland, has been studied as a natural analogue to deep disposal of radioactive wastes since 1988. The report gives a summary of the results of investigations carried out during the years 1992-1994. The Palmottu Analogue Project aims at a more profound understanding of radionuclide transport processes in fractured crystalline bedrock. The essential factors controlling transport are groundwater flow and interaction between water and rock. Accordingly, the study includes structural interpretations based in part on geophysical measurements, hydrological studies including hydraulic downhole measurements, flow modelling, hydrogeochemical characterization of groundwater, uranium chemistry and colloid chemistry, mineralogical studies, geochemical interpretation and modelling, including paleohydrogeological aspects, and studies of radionuclide mobilization and migration processes including numerical simulations. The project has produced a large amount of data related to natural analogue aspects. The data obtained have already been utilized in developing logical conceptual ideas of the time frames and processes operating in the bedrock of the site. (61 refs., 24 figs., 8 tabs.).

  12. The Palmottu natural analogue project. The behaviour of natural radionuclides in and around uranium deposits. Summary report 1992-1994

    International Nuclear Information System (INIS)

    Blomqvist, R.; Ruskeeniemi, T.; Ahonen, L.; Suksi, J.; Jakobsson, K.

    1995-06-01

    The Palmottu U-Th mineralization at Nummi-Pusula, southwestern Finland, has been studied as a natural analogue to deep disposal of radioactive wastes since 1988. The report gives a summary of the results of investigations carried out during the years 1992-1994. The Palmottu Analogue Project aims at a more profound understanding of radionuclide transport processes in fractured crystalline bedrock. The essential factors controlling transport are groundwater flow and interaction between water and rock. Accordingly, the study includes structural interpretations based in part on geophysical measurements, hydrological studies including hydraulic downhole measurements, flow modelling, hydrogeochemical characterization of groundwater, uranium chemistry and colloid chemistry, mineralogical studies, geochemical interpretation and modelling, including paleohydrogeological aspects, and studies of radionuclide mobilization and migration processes including numerical simulations. The project has produced a large amount of data related to natural analogue aspects. The data obtained have already been utilized in developing logical conceptual ideas of the time frames and processes operating in the bedrock of the site. (61 refs., 24 figs., 8 tabs.)

  13. State policies and requirements for management of uranium mining and milling in New Mexico. Volume IV. The supply of electric power and natural gas fuel as possible constraints on uranium production

    International Nuclear Information System (INIS)

    Page, G.B.

    1980-04-01

    The report contained in this volume considers the availability of electric power to supply uranium mines and mills. The report, submited to Sandia Laboratories by the New Mexico Department of Energy and Minerals (EMD), is reproduced without modification. The state concludes that the supply of power, including natural gas-fueled production, will not constrain uranium production

  14. Data base for a CANDU-PHW operating on a once-through, natural uranium fuel cycle

    International Nuclear Information System (INIS)

    1979-07-01

    This report, prepared for INFCE, describes a standard 600 MW(e) CANDU-PHW reactor operating on a once-through natural uranium fuel cycle. Subsequently, data are given for an extrapolated 1000 MW(e) design (the nominal capacity adopted for the INFCE study) operating on the same fuel cycle. (author)

  15. Contamination of roads in Klatovy by natural radionuclides from waste rock dumps of the former uranium mine Ustalec

    International Nuclear Information System (INIS)

    Nekl, M.; Golias, V.

    2002-01-01

    Contamination by natural radioisotopes was detected in the road network of the town Klatovy (Czech Republic). The extent and distribution of the contamination were studied using automobile and portable gamma ray spectrometers. Samples of the roadway were taken for a mineralogical and petrological study at two localities. Processes of re-distribution of uranium in the road and its surroundings were studied. (author)

  16. Chapter 5: Exponential experiments on natural uranium graphite moderated systems. II: Correlation of results with the method of Syrett (1961)

    International Nuclear Information System (INIS)

    Brown, G.; Moore, P.G.F.; Richmond, R.

    1963-01-01

    The results are given of exponential experiments on graphite moderated systems with fuel elements consisting of single rods and tubes of natural uranium metal. A correlation is given with the method of calculation proposed by Syrett (1961) and new consistent values of neutron yield and effective resonance integral are derived. (author)

  17. Elimination of natural uranium and {sup 226}Ra from contaminated waters by rhizofiltration using Helianthus annuus L

    Energy Technology Data Exchange (ETDEWEB)

    Vera Tome, F. [Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz (Spain)], E-mail: fvt@unex.es; Blanco Rodriguez, P. [Departamento de Fisica, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz (Spain); Lozano, J.C. [Laboratorio de Radiactividad Ambiental, Facultad de Ciencias, Universidad de Salamanca, 37008 Salamanca (Spain)

    2008-04-15

    The elimination of natural uranium and {sup 226}Ra from contaminated waters by rhizofiltration was tested using Helianthus annuus L. (sunflower) seedlings growing in a hydroponic medium. Different experiments were designed to determine the optimum age of the seedlings for the remediation process, and also to study the principal way in which the radionuclides are removed from the solution by the sunflower roots. In every trial a precipitate appeared which contained a major fraction of the natural uranium and {sup 226}Ra. The results indicated that the seedlings themselves induced the formation of this precipitate. When four-week-old seedlings were exposed to contaminated water, a period of only 2 days was sufficient to remove the natural uranium and {sup 226}Ra from the solution: about 50% of the natural uranium and 70% of the {sup 226}Ra were fixed in the roots, and essentially the rest was found in the precipitate, with only very small percentages fixed in the shoots and left in solution.

  18. Measurement of M{sup 3} and k{sub {infinity}} for heavy water natural uranium assembly

    Energy Technology Data Exchange (ETDEWEB)

    Popovic, D; Raisic, N; Markovic, H; Takac, S; Zdravkovic, Z; Lolic, B [Boris Kidric Institute of Nuclear Sciences, Vinca, Beograd (Yugoslavia)

    1959-03-15

    The migration length M and the infinite multiplication factor k{sub {infinity}} of the heavy water-natural uranium bare assembly are determined by measuring the reactivity of the reactor as function of the heavy water level. Since the assembly is non reflected the results obtained are of relatively high accuracy. (author)

  19. Estimations on uranium silicide fuel prototypes for their irradiation and postirradiation

    International Nuclear Information System (INIS)

    Sbaffoni, Maria M.

    2000-01-01

    The 'Silicide' project includes the qualification of this type of research reactor fuel to be used i.e. in the Argentine RA-3 and to confirm CNEA's role as an international supplier. The present paper shows complementary basic information for P-04 prototype post-irradiation, which is already under way, and some parameter values related to the new P-06 prototype to be taken into account for planning its irradiation and post-irradiation. The reliability of these values has been evaluated through comparison with experimental results. The reported results contribute, also, to a parallel study on the nuclear data libraries used in calculations for this type of reactor. (author)

  20. Method of chemical reprocessing of irradiated nuclear fuels (especially fuels containing uranium)

    International Nuclear Information System (INIS)

    Koch, G.

    1975-01-01

    The invention deals with a method for the extraction especially of fast breeder fuels of high burn-up. A quaternary ammonium nitrate of high molecular weight is put into an organic diluting medium as extraction agent, corresponding to the general formula NRR'R''R'''NO 3 where R,R' and R'' are aliphatic radicals, R''' a methyl radical and the sum of the C atoms is greater than 16. After the extraction of the aqueous nitric acid containing nuclear fuel solution with this extracting agent, uranium, plutonium (or also thorium) can be found to a very high percentage in the organic phase and can be practically quantitatively back-extracted by means of diluted nitric acid, sulphuric acid or acetic acid. By using 30 volume percent tricapryl methyl ammonium nitrate in diethyl benzene for example, a distribution coefficient of 10.3 is obtained for uranium. (RB/LH) [de

  1. 800-MeV proton irradiation of thorium and depleted uranium targets

    Energy Technology Data Exchange (ETDEWEB)

    Russell, G.J.; Brun, T.O.; Pitcher, E.J. [Los Alamos National Laboratory, NM (United States)] [and others

    1995-10-01

    As part of the Los Alamos Fertile-to-Fissile-Conversion (FERFICON) program in the late 1980`s, thick targets of the fertile materials thorium and depleted uranium were bombarded by 800-MeV protons to produce the fissile materials {sup 233}U and {sup 239}Pu, respectively. The amount of {sup 233}U made was determined by measuring the {sup 233}Pa activity, and the yield of {sup 239}Pu was deduced by measuring the activity of {sup 239}Np. For the thorium target, 4 spallation products and 34 fission products were also measured. For the depleted uranium target, 3 spallation products and 16 fission products were also measured. The number of fissions in each target was deduced from fission product mass-yield curves. In actuality, axial distributions of the products were measured, and the distributions were then integrated over the target volume to obtain the total number of products for each reaction.

  2. Comparative influence of dose rate and radiation nature, on lethality after big mammals irradiation

    International Nuclear Information System (INIS)

    Destombe, C.; Le Fleche, Ph.; Grasseau, A.; Reynal, A.

    1997-01-01

    For the same dose and the 30 days lethality as biological criterion, the dose rate influence is more important than the radiation nature on the results of an big mammals total body irradiation. (authors)

  3. Radiation enhanced thermal diffusion of chlorine in uranium dioxide; Diffusion thermique et sous irradiation du chlore dans le dioxyde d'uranium

    Energy Technology Data Exchange (ETDEWEB)

    Pipon, Yves [Ecole doctorale de physique et d' astrophysique, Universite Claude Bernard Lyon-I, Lyon (France)

    2006-12-15

    This work concerns the study of the thermal and radiation enhanced diffusion of {sup 36}Cl in uranium dioxide. It is a contribution to PRECCI programme (research programme on the long-term behaviour of the spent nuclear fuel). {sup 36}Cl is a long lived volatile activation product (T = 300 000 years) able to contribute significantly to the instant release fraction in geological disposal conditions. We simulated the presence of {sup 36}Cl by implanting a quantity of {sup 37}Cl comparable to the impurity content of chlorine in UO{sub 2}. In order to evaluate the diffusion properties of chlorine in the fuel and in particular to assess the influence of the irradiation defects, we performed two kinds of experiments: - the influence of the temperature was studied by carrying out thermal annealings in the temperature range 900 - 1300 deg. C; we showed that implanted chlorine was mobile from temperatures as low as 1000 deg. C and determined a thermal diffusion coefficient D{sub 1000} {sub deg.} {sub C} around 10{sup -16} cm{sup 2}s{sup -1} and deduced an activation energy of 4.3 eV. This value is one of lowest compared to that of volatile fission products such as iodine or the xenon. These parameters reflect the very mobile behaviour of chlorine; - the irradiation effects induced by fission products were studied by irradiating the samples with {sup 127}I (energy of 63.5 MeV). We showed that the implanted chlorine diffusion in the temperature range 30 - 250 deg. C is not purely athermal. In these conditions, the diffusion coefficient D{sub 250} {sub deg.} {sub C} for the implanted chlorine is around 10{sup -14} cm{sup 2}s{sup -1} and the activation energy is calculated to be 0.1 eV. Moreover, at 250 deg. C, we observed an important transport of the pristine chlorine from the bulk towards the surface. This chlorine comes from a zone where the defects are mainly produced by the nuclear energy loss process at the end of iodine range. We showed the importance of the

  4. Uranium enrichment plans

    International Nuclear Information System (INIS)

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

    1977-01-01

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

  5. Uranium enrichment plans

    International Nuclear Information System (INIS)

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

    1978-01-01

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

  6. Radiation monitoring of soil cover of natural uranium in the Issyk-Kul province

    International Nuclear Information System (INIS)

    Djenbaev, B.M.; Toktoeva, T.E.; Kaldibaev, B.K.; Zholbolduev, B.T.

    2015-01-01

    This article presents the current state in the radioecological soil Issyk-Kul province of natural uranium. Found that the background radiation - exposure dose and artificial radionuclides in the soil of the coastal zone of the lake as a whole at the level of the background and the acceptance of lower standards except for natural technogenic and some natural areas. Radioecological this province is mild natural and industrial uranium province.We have previously established 10 experimental plots around Issyk-Kul and the measurement showed that the power of natural background radiation in the gamma radiation of the coastal lake zone is an average of 17 to 25 mR/h in some areas up to 40 mR/h. As the distance from the lake to the side slopes of its level in some places rises to 40 mR/h, especially in some mountainous areas, canyons, which are based on the rocks, granites and their fragments are small, red sand, with a slightly increased radioactivity. For small areas with high natural background radiation can be attributed to the beaches of the coastal zone v. Jenish, v. Ak-Terek, located on the southern shore of Issyk-Kul Lake. The radioactivity of 30 - 60 mR/h, and in areas with a high content of iron in the sand inclusions level exposure dose increases up to 400 mR/h. Small areas of the coastal zone of Issyk-Kul Lake, mostly mud deposits with characteristic brilliance giving high radiation background. These areas include: the beach v.Tosor - 40-50 mR/h, 10 km west of the coast v.Kaji-Sai - 32-40 mR/h, the shore around with. Toru-Aigyr - 30 mR/h, the coast around v.Tamchi - 40-50 mR/h. In general, cities in the Issyk-Kul basin Kara-Kol, Cholpon-Ata and Balykchy radiation situation quite well, the average exposure dose of gamma radiation does not exceed 20 - 22 mR/h, but in some places the use of crushed granite, as filler and construction material, the level of background radiation increases to 40-50 mR/h This indicates that these natural resources, without first

  7. ESR analysis of natural and gamma irradiated coriander (Coriandrum sativum L.) seeds

    Science.gov (United States)

    Sezer, M. Özgür; Kaplan, Necati; Sayin, Ulku

    2017-12-01

    Electron spin resonance (ESR) is a powerful technique to detect radicals trapped in cellulosic food products and has been suggested as a useful method for identification of irradiated herbal foodstuffs. Coriander spice which has important medicinal properties was investigated using ESR spectroscopy. Radicals in natural and irradiated coriander samples were determined at room temperature. ESR spectra of natural sample were characterized by a single central signal with ? value and gamma irradiation produced satellite peaks attributed to cellulose-like radical which is used as a marker for detection of irradiated cellulosic plant products. The spectroscopic splitting values of radicals were determined. Dose dependency and stability of this center were analyzed by dose response and kinetic measurements. The reported results about activation energy, thermal life time and dose response relationship of the cellulose-like radical accurately prove that ESR can be used for identification of irradiated coriander spice seeds.

  8. Batch scale storage of sprouting foods by irradiation combined with natural low temperature; pt. 2

    International Nuclear Information System (INIS)

    Byun, M.W.; Lee, C.H.; Cho, H.O.; Kwon, J.H.; Yang, H.S.

    1982-01-01

    Two varieties of potatoes, Irish cobbler and Shimabara stored for seven and nine months respectively by irradiation combined with natural low temperature (year-round temperature change: 2-17degC) on a batch scale were investigated on the suitability for processing of potato chip. Nine months after storage, irradiated potatoes (Irish cobbler) tended to maintain somewhat better texture and sensory quality than untreated in potatoe chip processing. Peel rate, closely related to potato chip yield, of untreated potatoes were 20-25% higher than those of irradiated and Agtron color determination of potato chip from both irradiated were commercially acceptable. Preservation of potatoes by irradiation combined with natural low temperature was evaluated as an alternative method of the supply for raw materials of potato chip processing in the off-season in Korea. (Author)

  9. Batch scale strength of garlic by irradiation combined with natural low temperature

    International Nuclear Information System (INIS)

    Cho, H.O.; Kwon, J.H.; Byun, M.W.

    1984-01-01

    An attempt was made on the development of a commercial scale storage method of garlic by irradiation. Irradiated garlics with 50, 100 and 150 Gy were stored at natural low temperature storage room (12±6°C, 75-85% RH) and the physicochemical properties during the 10 months storage were investigated. The unirradiated garlic was mostly sprouted after 8 months storage, whereas the sprouting of all irradiated groups was completely inhibited until 10 months storage, The rotting rate and weigh loss of garlic after 10 months storage were reduced by 25 to 54% at 100 Gy irradiation compared with those of an unirradiated group. The moisture content remained relatively constant during the whole storage period. The total sugar content was increased with storage period. Ascorbic acid content was also decreased until 8 months storage but its content was rapidly increased along with sprouting. Garlic was marketable after 10 months storage by 100 Gy irradiation combined with natural low temperature. (author)

  10. Cell-metal interactions: A comparison of natural uranium to other common metals in renal cells and bone osteoblasts

    International Nuclear Information System (INIS)

    Milgram, S.; Carriere, M.; Thiebault, C.; Berger, P.; Khodja, H.; Gouget, B.

    2007-01-01

    Uranium acute intoxication has been documented to induce nephrotoxicity. Kidneys are the main target organs after short term exposures to high concentrations of the toxic, while chronic exposures lead to its accumulation in the skeleton. In this paper, chemical toxicity of uranium is investigated for rat osteoblastic bone cells and compared to results previously obtained on renal cells. We show that bone cells are less sensitive to uranium than renal cells. The influence of the chemical form on U cytotoxicity is demonstrated. For both cell types, a comparison of uranium toxicity with other metals or metalloids toxicities (Mn, Ni, Co, Cu, Zn, Se and Cd) permits classification of Cd, Zn, Se IV and Cu as the most toxic and Ni, Se VI , Mn and U as the least toxic. Chemical toxicity of natural uranium proves to be far less than that of cadmium. To try to explain the differences in sensitivities observed between metals and different cell types, cellular accumulations in cell monolayers are quantified by inductively coupled plasma-mass spectroscopy (ICP-MS), function of time or function of dose: lethal doses which simulate acute intoxications and sub-lethal doses which are more realistic with regard to environmentally metals concentrations. In addition to being more resistant, bone cells accumulated much more uranium than did renal cells. Moreover, for both cell models, Mn, U-citrate and U-bicarbonate are strongly accumulated whereas Cu, Zn and Ni are weakly accumulated. On the other hand, a strong difference in Cd behaviour between the two cell types is shown: whereas Cd is very weakly accumulated in bone cells, it is very strongly accumulated in renal cells. Finally, elemental distribution of the toxics is determined on a cellular scale using nuclear microprobe analysis. For both renal and osteoblastic cells, uranium was accumulated in as intracellular precipitates similar to those observed previously by SEM/EDS

  11. Cell-metal interactions: A comparison of natural uranium to other common metals in renal cells and bone osteoblasts

    Energy Technology Data Exchange (ETDEWEB)

    Milgram, S. [Laboratoire Pierre Suee, CEA-CNRS UMR 9956, CEA/Saclay, 91191 Gif-sur-Yvette (France); Carriere, M. [Laboratoire Pierre Suee, CEA-CNRS UMR 9956, CEA/Saclay, 91191 Gif-sur-Yvette (France); Thiebault, C. [Laboratoire Pierre Suee, CEA-CNRS UMR 9956, CEA/Saclay, 91191 Gif-sur-Yvette (France); Berger, P. [Laboratoire Pierre Suee, CEA-CNRS UMR 9956, CEA/Saclay, 91191 Gif-sur-Yvette (France); Khodja, H. [Laboratoire Pierre Suee, CEA-CNRS UMR 9956, CEA/Saclay, 91191 Gif-sur-Yvette (France); Gouget, B. [Laboratoire Pierre Suee, CEA-CNRS UMR 9956, CEA/Saclay, 91191 Gif-sur-Yvette (France)]. E-mail: barbara.gouget@cea.fr

    2007-07-15

    Uranium acute intoxication has been documented to induce nephrotoxicity. Kidneys are the main target organs after short term exposures to high concentrations of the toxic, while chronic exposures lead to its accumulation in the skeleton. In this paper, chemical toxicity of uranium is investigated for rat osteoblastic bone cells and compared to results previously obtained on renal cells. We show that bone cells are less sensitive to uranium than renal cells. The influence of the chemical form on U cytotoxicity is demonstrated. For both cell types, a comparison of uranium toxicity with other metals or metalloids toxicities (Mn, Ni, Co, Cu, Zn, Se and Cd) permits classification of Cd, Zn, Se{sup IV} and Cu as the most toxic and Ni, Se{sup VI}, Mn and U as the least toxic. Chemical toxicity of natural uranium proves to be far less than that of cadmium. To try to explain the differences in sensitivities observed between metals and different cell types, cellular accumulations in cell monolayers are quantified by inductively coupled plasma-mass spectroscopy (ICP-MS), function of time or function of dose: lethal doses which simulate acute intoxications and sub-lethal doses which are more realistic with regard to environmentally metals concentrations. In addition to being more resistant, bone cells accumulated much more uranium than did renal cells. Moreover, for both cell models, Mn, U-citrate and U-bicarbonate are strongly accumulated whereas Cu, Zn and Ni are weakly accumulated. On the other hand, a strong difference in Cd behaviour between the two cell types is shown: whereas Cd is very weakly accumulated in bone cells, it is very strongly accumulated in renal cells. Finally, elemental distribution of the toxics is determined on a cellular scale using nuclear microprobe analysis. For both renal and osteoblastic cells, uranium was accumulated in as intracellular precipitates similar to those observed previously by SEM/EDS.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-10-01

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

  13. A plant taxonomic survey of the Uranium City region, Lake Athabasca north shore, emphasizing the naturally colonizing plants on uranium mine and mill wastes and other human-disturbed sites

    International Nuclear Information System (INIS)

    Harms, V.L.

    1982-07-01

    A goal of this study was to acquire more complete baseline data on the existing flora of the Uranium City region, both in natural and human-disturbed sites. Emphasis was given to determining which plant species were naturally revegetating various abandoned uranium mine and mill waste disposal areas, other human-disturbed sites, and ecologically analogous sites. Another goal was to document the occurrence and distribution in the study region of rare and possibly endangered species. A further objective was to suggest regionally-occurring species with potential value for revegetating uranium mine and mill waste sites. Field investigations were carried out in the Uranium City region during August, 1981. During this time 1412 plant collections were made; a total of 366 plant species - trees, shrubs, forbs, graminoids, lichens, and bryophytes were recorded. The report includes an annotated checklist of plant species of the Uranium City region and a reference index of plant taxa indicating species that have high revegetation potential

  14. Assay of uranium in crude diuranate cakes and MgF2 slag produced at the natural uranium conversion plants by γ-ray spectrometry

    International Nuclear Information System (INIS)

    Kalsi, P.C.; Iyer, R.H.

    1993-01-01

    A transmission-corrected γ-ray counting method has been employed for the assay of uranium in crude Na 2 U 2 O 7 cakes produced at the Uranium Conversion Facilities. A 3''*3'' NaI(Tl) detector was used in conjunction with a 400-channel analyzer. The observed count rate of the 1 MeV γ-ray emitted by the 238 U in the sample was corrected for sample self-attenuation, measured with a 65 Zn (γ-energy ≅ 1115 keV) transmission source. A calibration factor determined by measuring a standard of known amount of radioactive material in the same form and geometry as the unknown sample was used to convert the transmission corrected count rate to the amount of uranium in the weighed sample. Another γ-spectrometric method is described for the assay of the U-content in the MgF 2 slag produced during the magnesiothermic reduction of UF 4 to U-metal ingots at the natural U-conversion plant. (author) 8 refs.; 3 figs.; 1 tab

  15. Distribution of natural radionuclides of uranium and thorium series in the process of artesian water treatment for drinking consumption

    International Nuclear Information System (INIS)

    Grashchenko, S.M.; Gritchenko, Z.G.; Shishkunova, L.V.

    1997-01-01

    Distribution of natural radionuclides of uranium and thorium series during the treatment of artesian water for drinking consumption is studied using vacuum-emanation and gamma spectrometry methods. During the water treatment hydroxide precipitates are produced at the station, which are isolated using a sand filter, radium isotopes being coprecipitated alongside with them. As a result of this radioactive waste is accumulated at the station, radium isotope concentration in it being equivalent to radium isotope concentration in uranium-thorium ores with 0:11% uranium and 0.56% thorium content. radium isotope concentration in water, delivered to the user do not exceed the established domestic normatives do not exceed the established domestic normatives

  16. Study contribution to the new international philosophy of the radiological safety system on chemical processing of the natural uranium

    International Nuclear Information System (INIS)

    Silva, T.M. da.

    1988-01-01

    The objective of the work is to adapt the radiological Safety System in the facilities concerned to the chemical treatment of the uranium concentrated (yellow-cake) until conversion in uranium hexafluoride in the pilot plant of IPEN-CNEN/SP, to the new international philosophy adopted by the International Commission Radiological on Protection ICPR publication 22(1973), 26(1977), 30(1978) and the International Atomic Energy Agency IAEA publication 9(1982). The new philosophy changes fully the Radiological Protection concepts of preceding philosophy, changes, also, the concept of the work place and individual monitoring as well as the classification of the working areas. These new concepts are applied in each phase of the natural uranium treatment chemical process in conversion facility. (author)

  17. Some economic aspects of natural uranium graphite gas reactor types. Present status and trends of costs in France

    International Nuclear Information System (INIS)

    Gaussens, J.; Tanguy, P.

    1964-01-01

    The first part of this report defines the economic advantages of natural uranium fuels, which are as follows: the restricted number and relatively simple fabrication processes of the fuel elements, the low cost per kWh of the finished product and the reasonable capital investments involved in this type of fuel cycle as compared to that of enriched uranium. All these factors combine to reduce the arbitrary nature of cost estimates, which is particularly marked in the case of enriched uranium due to the complexity of its cycle and the uncertainties of plutonium prices). Finally, the wide availability of yellowcake, as opposed to the present day virtual monopoly of isotope separation, and the low cost of natural uranium stockpiling, offer appreciable guarantees in the way of security of supply and economic and political independence as compared with the use of enriched uranium. As far as overall capital investments are concerned, it is shown that, although graphite-gas reactor costs are higher than those of light water reactors in certain capacity ranges, the situation becomes far less clear when we start taking into account, in the interest of national independence, the cost of nuclear fuel production equipment in the case of each of these types of reactor. Finally, the marginal cost of the power capacity of a graphite-gas reactor is low and its technological limitations have receded (owing particularly to the use of prestressed concrete). It is a well known fact that the trend is now towards larger power station units, which means that the rentability of natural uranium graphite reactors as compared to other types of reactors will become more and more pronounced. The second section aims at presenting a realistic short and medium term view of the fuel, running, and investment costs of French natural uranium graphite gas, reactors. Finally, the economic goals which this type of reactor can reach in the very near future are given. It is thus shown that considerable

  18. Mass balances by uranium-series disequilibria in natural phosphate deposits and mine products

    International Nuclear Information System (INIS)

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

    1985-01-01

    In a closed system U-238 is in radioactive equilibrium with its longer lived daughters, U-234, Th-230, and Ra-226. In a system that is open on a time scale of 10 4 to 10 5 years, as in rock weathering, the various daughters and isotopes become separated. Nevertheless, equilibrium still pertains to the total system, so that material balances between weathering components and residual products can be calculated, based on parent-daughter radioactivity ratios. The authors have applied this balancing concept to the weathering of phosphatic ores in central Florida and to phosphate mining products. In the natural system studied in Florida, the leached zones are ten times more extensive than enriched zones, and have higher concentrations of Th-230 and Ra-226 relative to U-238 and U-234. Although there are significant movements of long-lived radio-elements locally, and occasional notable disequilibria of short-lived daughters, leaching by ground water is not a major factor in the regional budget. In the mining process, uranium follows the enriched phosphate and also the clay residues. Thorium and radium follow the clay residues and the gypsum by-product. Mine effluent waters, although somewhat higher in radioactivity than natural waters, do not remove appreciable amounts of the radio-elements

  19. 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)

  20. Preparation of irradiated natural rubber latex-styrene copolymer for electrical gloves

    International Nuclear Information System (INIS)

    Made Sumarti Kardha

    2010-01-01

    Research on irradiated natural rubber latex-styrene copolymer to prepare electrical glove have been done. Vulcanization of natural rubber latex (NRL) was done by mixing 2 phr (per hundred of rubber) of normal butyl acrylate (n-BA) emulsion then irradiated with ã-ray "6"0Co at the dose of 30 kGy producing irradiated natural rubber latex (INRL). Natural rubber latex-styrene copolymers (SC) were prepared by mixing NRL and styrene monomer at styrene concentrations of 50 phr, 75 phr, 100 phr, 500 phr and irradiated at the doses of 15 kGy, 30 kGy and 45 kGy, then characterized their latex and film properties to obtain optimum SC of SC50. This optimum SC, SC50 then mixed with IRNL at the weight ratio of 0/100, 30/70, 50/50, 70/30 and 100/0, to produce irradiated natural rubber latex-styrene copolymer. The properties of copolymer rubber films made by dipping process i.e., % conversion, total solid content, latex viscosity, tensile strength, modulus 300 %, elongation at break, electrical resistance and dielectric constant were then characterized. Characterization result showed that (INRL-SC50) with 50/50 ratio irradiated at the dose of 30 kGy, have % conversion of 80.93 %, electrical resistivity of 1.73 x 10"1"4 Ohm cm and dielectric constant of 2.76 which fulfill the requirement as material for electrical gloves. (author)

  1. Fabrication and irradiation testing of LEU [low enriched uranium] fuels at CRNL status as of 1987 September

    International Nuclear Information System (INIS)

    Sears, D.F.; Berthiaume, L.C.; Herbert, L.N.

    1987-01-01

    The current status of Chalk River Nuclear Laboratories' (CRNL) program to develop and test low-enriched uranium (LEU), proliferation-resistant fuels for use in research reactors is reviewed. CRNL's fuel manufacturing process has been qualified by the successful demonstration irradiation of 7 full-size rods in the NRU reactor. Now industrial-scale production equipment has been commissioned, and a fuel-fabrication campaign for 30 NRU rods and a MAPLE-X core is underway. Excess capacity could be used for commercial fuel fabrication. In the irradiation testing program, mini-elements with deliberately included core surface defects performed well in-reactor, swelling by only 7 to 8 vol% at 93 atomic percent burnup of the original U-235. The additional restraint provided by the aluminium cladding which flowed into the defects during extrusion contributed to this good performance. Mini-elements containing a variety of particle size distributions were also successfully irradiated to 93 at% burnup in NRU, as part of a study to establish the optimum particle size distribution. Swelling was found to be proportional to the percentage of fines (<44μm particles) contained in the cores. The mini-elements containing the composition normally used at CRNL had swollen by 5.8 vol%, and mini-elements with a much higher percentage of fines had swollen by 6.8 vol%, at 93 at% burnup. Also, a program to develop LEU targets for Mo-99 production, via the technology developed to fabricate dispersed silicide fuel, has started, and preliminary scoping studies are underway. (Author)

  2. Simultaneous determination of Ra-226, natural uranium and natural thorium by gamma-ray spectrometry INa(Ti), in solid samples.; Determinacion de U (Natural), Th (Natural) y Ra-226 en diversos materiales, mediante espectrometria con INa (TI)

    Energy Technology Data Exchange (ETDEWEB)

    Salvador, S.; Navarro, T.; Alvarez, A.

    1991-07-01

    A method has been developed to determine activities of Ra-226, natural uranium and natural thorium by gamma-ray spectrometry. The measurement system has been calibrated using standards specially prepared at the laboratory. It is necessary to assume secular equilibrium in the samples, between Ra-226 and Th-232 and its daughters nuclides, and between U-238 and its immediate daughter Th-234, as the photo peaks measured are those of the daughters. The results obtained indicate that this method can of ter replace the radiochemical techniques used to measure activities in this type of sample. The method has been successfully used to determine these natural isotopes in samples from uranium mills. (Author) 9 refs.

  3. Analysis of uranium and thorium thin targets irradiated at the PSI accelerator

    International Nuclear Information System (INIS)

    Wenger, H.U.; Botta, F.; Chawla, R.; Daum, M.; Gavillet, D.; Hegedues, F.; Ingold, F.; Kopajtic, Z.; Ledergerber, G.; Linder, H.P.; Roellin, S.; Wichser, J.; Wyss, F.

    1997-01-01

    The aim of the ATHENA programme at PSI is to provide experimental data for the validation of theoretical models in nucleon-meson transport codes used for accelerator-based transmutation studies. Emphasis is placed on the mass yield distribution of spallation and fission products for irradiated thin actinide targets. This paper presents results of an irradiation experiment carried out with 238 UO 2 and 232 ThO 2 . Isobaric production cross-sections of fission and spallation products based on mass spectrometric measurements and γ-spectroscopy are compared with calculations carried out using the HETC code and the RAL high-energy fission model. (author) 6 figs., 8 refs

  4. Simultaneous determination of Ra-226, natural uranium and natural thorium by gamma-ray spectrometry INa(Ti), in solid samples

    International Nuclear Information System (INIS)

    Salvador, S.; Navarro, T.; Alvarez, A.

    1991-01-01

    A method has been developed to determine activities of Ra-226, natural uranium and natural thorium by gamma-ray spectrometry. The measurement system has been calibrated using standards specially prepared at the laboratory. It is necessary to assume secular equilibrium in the samples, between Ra-226 and Th-232 and its daughters nuclides, and between U-238 and its immediate daughter Th-234, as the photo peaks measured are those of the daughters. The results obtained indicate that this method can of ter replace the radiochemical techniques used to measure activities in this type of sample. The method has been successfully used to determine these natural isotopes in samples from uranium mills. (Author) 9 refs

  5. 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

  6. Wood Sawdust/Natural Rubber Ecocomposites Cross-Linked by Electron Beam Irradiation

    Directory of Open Access Journals (Sweden)

    Elena Manaila

    2016-06-01

    Full Text Available The obtaining and characterization of some polymeric eco-composites based on wood sawdust and natural rubber is presented. The natural rubber was cross-linked using the electron beam irradiation. The irradiation doses were of 75, 150, 300 and 600 kGy and the concentrations of wood sawdust were of 10 and 20 phr, respectively. As a result of wood sawdust adding, the physical and mechanical properties such as hardness, modulus at 100% elongation and tensile strength, showed significant improvements. The presence of wood sawdust fibers has a reinforcing effect on natural rubber, similar or better than of mineral fillers. An increase in the irradiation dose leads to the increasing of cross-link density, which is reflected in the improvement of hardness, modulus at 100% elongation and tensile strength of blends. The cross-linking rates, appreciated using the Flory-Rehner equation, have increased with the amount of wood sawdust in blends and with the irradiation dose. Even if the gel fraction values have varied irregularly with the amount of wood sawdust and irradiation dose it was over 90% for all blends, except for the samples without wood sawdust irradiated with 75 kGy. The water uptake increased with increasing of fiber content and decreased with the irradiation dose.

  7. Determination of uranium in industrial and environmental samples. Vol. 4

    Energy Technology Data Exchange (ETDEWEB)

    El-Sweify, F H; Shehata, M K; Metwally, E M; El-Shazly, E A.A.; El-Naggar, H A [Nuclear Chemistry Department, Hot Laborities Center, Atomic Energy Authority, Cairo (Egypt)

    1996-03-01

    The phosphate ores used at `Abu zaabal fertilizer and chemical company` for the production of some chemicals and fertilizers contain detectable amounts of uranium. In this study, the content of uranium in samples of different products of fertilizers, gypsum, and phosphate ore were determined using NAA, and gamma ray spectroscopy of the irradiated samples. Another method based on measuring the natural radioactivity of {sup 238} U series for non-irradiated samples using gamma-ray spectroscopy was also used for determine uranium content in the samples. In the NAA method, the content of U(ppm) in the samples was been computed from the photopeak activity of the lines = 106.1, 228.2, and 277.5 KeV of {sup 239} Np induced in the irradiated samples, and the uranium standard simultaneously irradiated. the gamma-ray spectra, and the decay curves are given. In the second method the gamma-ray spectra of the natural radioactivity of the samples and uranium standard were measured. The gamma-transition of energies 295.1, 251.9 KeV for {sup 214} Pb; 609.3, 768.4, 1120.3, 1238.1 KeV for {sup 214} Bi were determined. The uranium {sup 23U} traces in drainage water was also determined spectrophotometrically using arsenazo-III after preconcentration of uranium from the pretreated drainage water in column packed with chelex-100 resin. The recovery was found to be 90 {+-} 5%. 11 figs., 3 tabs.

  8. An IBM-1620 code for calculaton of isotopic composition of irradiated uranium (ISOCOM-1)

    International Nuclear Information System (INIS)

    Soliman, R.H.; Karchava, G.; Hamouda, I.

    1974-01-01

    The present work gives a description of an IBM-1620 code to calculate the isotopic composition during the irradiation of a nuclear fuel, which initially consists of 235 U and 238 U. The numerical results of test calculations as well as the ET-RR-1 reactor calculations are presented. The code is in operation since 1968

  9. The effect of natural weathering on irradiated polyethylene films

    International Nuclear Information System (INIS)

    Khoylou, F.; Hassan Pour, S.

    2002-01-01

    Polyethylene is one of the extensive used plastics in outdoor uses. Outdoor durability of PE in modem agriculture is very important because of large scale food production. UV radiations contained in solar spectrum are the main cause of degradation in outdoor uses of plastics. So, light stabilization of PE has made considerable progress since the early years of its outdoor use. Radiation crosslinking of PE films for improving UV stability is one of the new research fields. In this work,the effect of UV stabilizers on the chemical and mechanical stability of PE have been compared with UV stabilizers and radiation crosslinking together. For this reason two low density polyethylene films were prepared.One film contained 3% of photostabilizers and antioxidant,and the other film was free of additives. The films were irradiated by EB at doses of 30-300 kGy, these crosslinked PE films were exposed to the outdoor condition for 2 years. Determination of the gel content shows that significant crosslinking yields are obtained at high doses. Effect of crosslinking and outdoor exposure on the degradation of stabilized and unstabilized PE films have been studied by FTIR. Data of FTIR show that outdoor degradation of unstabilized PE promote rapidly after irradiation and cause to distortion of samples after 4 months. While, stabilized PE samples show low changes during 2 years outdoor exposure. Mechanical properties of stabilized and unstabilized crosslinked PE films are also presented in this paper. (Author)

  10. Determination of radium and uranium isotopes in natural waters by sorption on hydrous manganese dioxide followed by alpha-spectrometry

    International Nuclear Information System (INIS)

    Bojanowski, R.; Radecki, Z.; Burns, K.

    2005-01-01

    Water samples, spiked with 133 Ba and 232 U radiotracers, are scavenged for radium and uranium isotopes using hydrous manganese dioxide which is produced in-situ, by reacting manganese (+2) and permanganate ions at pH 8-9. The precipitate is solubilized with ascorbic and acetic acids and the resulting solution filtered through a glass fibre filter GF/F to remove particulate matter. The radium is co-precipitated with barium ions by the addition of a saturated Na 2 SO 4 solution where a small amount of BaSO 4 suspension is introduced to initiate crystallization. The micro precipitate containing the radium is collected on a 0.1 membrane filter and the filtrate saved for follow-up uranium analysis. The 226 Ra on the filter is determined by alpha-spectrometry and its recovery is assessed by measuring the 133 Ba on the same filter using gamma-spectrometry. The filtrate containing uranium is passed through a Dowex AG 1 x 4 ion-exchange resin in the SO 4 2- form which retains uranium while other ions are eluted by dilute (0.25M) sulphuric acid. Uranium is eluted from the column by distilled water, electrodeposited on a silver disc and the uranium isotopes and their recovery are determined by alpha-spectrometry. The method was tested on a variety of natural and spiked water samples with known concentrations of 226 Ra and 238 U and was found to yield accurate results within ±10% RSD of the target values. (author)

  11. Contribution to the study of the desorption of fission gases formed in irradiated uranium oxide; Contribution a l'etude de la desorption des gaz de fission formes dans l'oxyde d'uranium irradie

    Energy Technology Data Exchange (ETDEWEB)

    Berry, J -L; Darras, R; Roger, B [Commissariat a l' Energie Atomique, Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)

    1966-09-01

    The release of {sup 133}Xe from irradiated UO{sub 2} has been studied in the temperature range 1300 to 1900 deg C, using various monocrystalline or sintered samples. Up to 1600 deg C, this release is proportional to the square root of the time and thus occurs essentially by diffusion. The apparent diffusion constant D' decreases and the activation energy of the corresponding process increases as the integrated neutron flux received by the fuel increases. As the density of the sintered samples decreases however, the activation energy of the release also decreases, so that the difference between D' values for sintered samples of different densities decreases as the temperature rises. Finally, above 1600 deg C, the fission gas release phenomenon is governed by UO{sub 2} evaporation, and all the different types of oxide studied have similar behaviors, characterized by poor retention of these gases. (authors) [French] La desorption du xenon 133 forme dans le bioxyde d'uranium irradie a ete etudiee dans l'intervalle de 1300 a 1900 C, a l'aide de differents echantillons monocristallins ou frittes. Jusqu'a 1600 C, elle s'effectue proportionnellement a la racine carree du temps, donc essentiellement par diffusion. La pseudo-constante de desorption D' decroit et l'energie d'activation du processus correspondant croit lorsque le flux de neutrons integre recu par le combustible augmente. Cependant, lorsque la densite des frittes diminue, l'energie d'activation de desorption diminue egalement, de sorte que l'ecart entre les valeurs de D' relatives a des frittes de densites differentes se restreint lorsque, la temperature s'eleve. Finalement, au-dessus de 1600 C, l'evaporation de l'UO{sub 2} regit le phenomene de liberation des gaz de fission, et toutes les qualites d'oxyde etudiees presentent alors des comportements voisins a cet egard, caracterises par une mediocre retention de ces gaz. (auteurs)

  12. Evaluation of 99Mo/99mTc generator experiment using PZC material and irradiated natural molybdenum

    International Nuclear Information System (INIS)

    Khongpetch, P.; Chingjit, S.; Dangprasert, M.; Rangsawai, W.; Virawat, N.

    2006-01-01

    Technetium-99m ( 99m Tc) is the most widely used radioisotope in nuclear medicine, accounting for more than 80% of all diagnostic nuclear medicine procedure. 99m Tc is almost exclusively produced from the decay of its parent molybdenum-99 ( 99 Mo). The present sources of 99 Mo are research reactors by using the (n, γ) nuclear reaction with natural molybdenum, resulting in inexpensive but low specific activity 99 Mo, or by neutron-induced fission of uranium-235, which result in expensive but high specific activity 99 Mo. The technology requirement for processing of 99 Mo from the (n, γ) 'activation method' is rather simple, and is within the reach of most developing countries operating research reactors. In the fission method' the technological and infrastructure requirements are some complex, and possibly can be sustained only by countries with advanced nuclear technology. To overcome these difficulties, Japan Atomic Energy Research Institute (JAERI) and KAKEN company have developed alternative technology for 99 Mo/ 99m Tc generator by using a molybdenum absorbent called Poly Zirconium compound (PZC) and irradiated natural molybdenum. The paper describes experiments for evaluation the performance of PZC as a column packing material for 99 Mo/ 99m Tc generator from (n, γ) 99 Mo. (author)

  13. Measurement of the effective resonance integral of natural uranium; Merenje efektivnog rezonantnog integrala prirodnog urana

    Energy Technology Data Exchange (ETDEWEB)

    Markovic, V; Kocic, A [Institute of nuclear sciences Boris Kidric, Vinca, Beograd (Yugoslavia)

    1965-12-15

    Good understanding of the nuclear properties of the materials in the reactor core is essential for reactor operation. One of the fundamental properties is the resonance absorption of the fuel, which is directly included in the reactor calculation through resonance escape probability and influences the choice of the materials quality in the core. This paper describes the measurement of resonance absorption integral of the natural uranium as a function of the S/M ratio. Improved experiment planning and analysis of results, as well as improvement of the ROB-1 reactor oscillator device related to the interpretation of results and decrease of reactor drift variations during measurement enabled higher precision of results compared to previous experiments. Poznavanje osobina nuklearnih karakteristika materijala koji ulaze u jezgro nuklearnog reaktora predstavlja bitan faktor u njegovom rezimu rada. Jedna od osnovnih je svakako rezonantna apsorpcija goriva, cija velicina - preko faktora rezonantnog izbegavanja - direktno ulazi u proracun nuklearnih reaktora i utice na izbor kvaliteta materijala koji ga sacinjavaju. U radu se opisuje merenje rezonantnog apsorpcionog integrala prirodnog urana u funkciji odnosa S/M. Bolja postavka eksperimenta i interpretacija rezultata, s jedne strane, i poboljsanje uredjaja reaktorskog oscilatora ROB-1 /1/ u pogledu analize podataka i smanjenja promene drifta reaktora u toku merenja, s druge strane, daju znacaj ovom radu u pogledu dobijanja preciznijih rezultata u odnosu na ranije /2/ (author)

  14. Uranium(IV) adsorption by natural organic matter in anoxic sediments

    Energy Technology Data Exchange (ETDEWEB)

    Bone, Sharon E.; Dynes, James; Cliff, John B.; Barger, John

    2017-01-09

    Uranium is an important fuel source and a global environmental contaminant. It accumulates in the tetravalent state, U(IV), in anoxic sediments, including ore deposits, marine basins, and contaminated aquifers. However, very little is known about the speciation of U(IV) in low temperature geochemical environments, inhibiting the development of a conceptual model of U behavior. Until recently, U(IV) was assumed to exist predominantly as the sparingly soluble mineral uraninite (UO2) in anoxic sediments; yet studies now show that UO2 is not often dominant in these environments. However, a model of U(IV) speciation under environmentally relevant conditions has not yet been developed. Here we show that complexes of U(IV) adsorb on organic carbon and organic carbon-coated clays in an organic-rich natural substrate under field-relevant conditions. Whereas previous research assumed that the U(IV) product depended on the reduction pathway, our results demonstrate that UO2 formation can be inhibited simply by decreasing the U:solid ratio. Thus, it is the number and type of surface ligands that controls U(IV) speciation subsequent to U(VI) reduction. Projections of U transport and bioavailability, and thus its threat to human and ecosystem health, must consider retention of U(IV) ions within the local sediment environment.

  15. Experiences from the Swedish programme - heavy water and natural uranium in the Aagesta cogeneration plant

    International Nuclear Information System (INIS)

    Oestman, Alvar

    2002-11-01

    A short review of the Swedish programme for nuclear power in the 50's and the 60's is given, and in particular a description of the operating experiences of the Aagesta nuclear cogeneration plant, producing district heating for the south Stockholm area (12 MW el and 68 MW heat ). The original Swedish nuclear programme was built on heavy water and natural uranium and had the objective to construct small nuclear plants in the vicinity of some 10 large cities in south and middle Sweden. Aagesta was the only full-scale plant to be built according to this programme, as Sweden adopted the light-water reactor policy and eventually constructed 12 large reactors at four sites. The report is based on the experiences of the author from his work at the Aagesta plant in the sixties. In an appendix, the experiences from Vattenfall (the Swedish electric utility which took over the operating responsibility for the Aagesta plant), of the plant operation is reviewed

  16. Assessment of the Central Effects of Natural Uranium via Behavioural Performances and the Cerebrospinal Fluid Metabolome

    Directory of Open Access Journals (Sweden)

    P. Lestaevel

    2016-01-01

    Full Text Available Natural uranium (NU, a component of the earth’s crust, is not only a heavy metal but also an alpha particle emitter, with chemical and radiological toxicity. Populations may therefore be chronically exposed to NU through drinking water and food. Since the central nervous system is known to be sensitive to pollutants during its development, we assessed the effects on the behaviour and the cerebrospinal fluid (CSF metabolome of rats exposed for 9 months from birth to NU via lactation and drinking water (1.5, 10, or 40 mg·L−1 for male rats and 40 mg·L−1 for female rats. Medium-term memory decreased in comparison to controls in male rats exposed to 1.5, 10, or 40 mg·L−1 NU. In male rats, spatial working memory and anxiety- and depressive-like behaviour were only altered by exposure to 40 mg·L−1 NU and any significant effect was observed on locomotor activity. In female rats exposed to NU, only locomotor activity was significantly increased in comparison with controls. LC-MS metabolomics of CSF discriminated the fingerprints of the male and/or female NU-exposed and control groups. This study suggests that exposure to environmental doses of NU from development to adulthood can have an impact on rat brain function.

  17. Assessment of the Central Effects of Natural Uranium via Behavioural Performances and the Cerebrospinal Fluid Metabolome.

    Science.gov (United States)

    Lestaevel, P; Grison, S; Favé, G; Elie, C; Dhieux, B; Martin, J C; Tack, K; Souidi, M

    2016-01-01

    Natural uranium (NU), a component of the earth's crust, is not only a heavy metal but also an alpha particle emitter, with chemical and radiological toxicity. Populations may therefore be chronically exposed to NU through drinking water and food. Since the central nervous system is known to be sensitive to pollutants during its development, we assessed the effects on the behaviour and the cerebrospinal fluid (CSF) metabolome of rats exposed for 9 months from birth to NU via lactation and drinking water (1.5, 10, or 40 mg·L(-1) for male rats and 40 mg·L(-1) for female rats). Medium-term memory decreased in comparison to controls in male rats exposed to 1.5, 10, or 40 mg·L(-1) NU. In male rats, spatial working memory and anxiety- and depressive-like behaviour were only altered by exposure to 40 mg·L(-1) NU and any significant effect was observed on locomotor activity. In female rats exposed to NU, only locomotor activity was significantly increased in comparison with controls. LC-MS metabolomics of CSF discriminated the fingerprints of the male and/or female NU-exposed and control groups. This study suggests that exposure to environmental doses of NU from development to adulthood can have an impact on rat brain function.

  18. Soil and vegetation influence in plants natural radionuclides uptake at a uranium mining site

    Science.gov (United States)

    Charro, E.; Moyano, A.

    2017-12-01

    The main objective of this work is to investigate the uptake of several radionuclides by the vegetation characteristic of a dehesa ecosystem in uranium mining-impacted soils in Central-West of Spain. The activity concentration for 238U, 226Ra, 210Pb, 232Th, and 224Ra was measured in soil and vegetation samples using a Canberra n-type HPGe gamma-ray spectrometer. Transfer factors of natural radionuclides in different tissues (leaves, branches, twigs, and others) of native plants were evaluated. From these data, the influence of the mine, the physicochemical parameters of the soils and the type of vegetation were analyzed in order to explain the accumulation of radionuclides in the vegetation. A preferential uptake of 210Pb and 226Ra by plants, particularly by trees of the Quercus species (Quercus pyrenaica and Quercus ilex rotundifolia), has been observed, being the transfer factors for 226Ra and 210Pb in these tree species higher than those for other plants (like Pinus pinaster, Rubur ulmifolius and Populus sp.). The analysis of radionuclide contents and transfer factors in the vegetation showed no evidence of influence of the radionuclide concentration in soils, although it could be explained in terms of the type of plants and, in particular, of the tree's species, with special attention to the tree's rate of growth, being higher in slow growing species.

  19. Fixation and reduction of uranium by natural organic matter: reaction mechanisms and kinetics

    International Nuclear Information System (INIS)

    Nakashima, S.; Perruchot, A.; Trichet, J.; Disnar, J.R.

    1987-01-01

    The reactivity of lignite towards soluble uranyl species in an aqueous medium is experimentally investigated as a function of temperature (between 20 0 C and 400 0 C). The fixation process starts near 45 0 C, with reduction beginning around 120 0 C. The fixation process leads to the formation of chemically and thermally stable organo-uranyl species. The reduction of free uranyl species is accompanied by a stoichiometric (2:1) liberation of protons into the medium. These protons originate from the organic matter which thus undergoes dehydrogenation. The general evolution of the carbonaceous residue in the course of this reaction shows that alcoholic and aliphatic hydrocarbon groups are responsible for the reduction. This chemical dehydrogenation could explain the low hydrogen content of natural organic materials associated with uraniferous deposits. The kinetics of the reduction step have been studied at 180 0 C, 190 0 C and 200 0 C. The kinetic parameters determined over this temperature range, and the extrapolation made to 20 0 C, show that reduction can be a crucial process in the geochemical behaviour of uranium especially in the thermal conditions in which sedimentary basins evolve [fr

  20. Natural uranium fueled light water moderated breeding hybrid power reactors: a feasibility study

    International Nuclear Information System (INIS)

    Greenspan, E.; Schneider, A.; Misolovin, A.; Gilai, D.; Levin, P.

    1978-06-01

    The first part of the study consists of a thorough investigation of the properties of subcritical thermal lattices for hybrid reactor applications. Light water is found to be the best moderator for (fuel-self-sufficient) FSS hybrid reactors for power generation. Several lattice geometries and compositions of particular promise for LWHRs are identified. Using one of these lattices, fueled with natural uranium, the performance of several concepts of LWHR blankets is investigated, and optimal blanket designs are identified. The effect of blanket coverage efficiency and the feasibility of separating the functions of tritium breeding and of power generation to different blankets are investigated. Optimal iron-water shields for LWHRs are also determined. The performance of generic types of LWHRs is evaluated. The evolution of the blanket properties with burnup is evaluated and fuel management schemes are briefly examined. The feasibility of using the lithium system of the blanket to control the blanket power amplitude and shape is also investigated. A parametric study of the energy balance of LWHR power plants is carried out, and performance parameters expected from LWHRs are estimated. Discussions are given of special features of LWHRs and their fuel cycle

  1. Organic matter and containment of uranium and fissiogenic isotopes at the Oklo natural reactors

    International Nuclear Information System (INIS)

    Nagy, B.; Rigali, M.J.; Davis, D.W.; Parnell, J.

    1991-01-01

    Some of the Precambrian natural fission reactors at Oklo in Gabon contain abundant organic matter, part of which was liquefied at the time of criticality and subsequently converted to a graphitic solid. The liquid organic matter helps to reduce U(VI) to U(IV) from aqueous solutions, resulting in the precipitation of uraninite. It is known that in the prevailing reactor environments, precipitated uraninite grains incorporated fission products. We report here observations which show that these uraninite crystals were held immobile within the re-solidified, graphitic bituminous organics at Oklo thus enhanced radionuclide containment. Uraninite encased in solid graphitic matter in the organic-rich reactor zones lost virtually no fissiogenic lanthanide isotopes. The first major episode of uranium and lead migration was caused by the intrusion of a swarm of adjacent dolerite dykes about 1,100 Myr after the reactors went critical. Our results from Oklo imply that the use of organic, hydrophobic solids such as graphitic bitumen as a means of immobilizing radionuclides in pre-treated nuclear waste warrants further investigation. (author)

  2. Global resources and energy trade. An overview for coal, natural gas, oil and uranium

    Energy Technology Data Exchange (ETDEWEB)

    Remme, U.; Blesl, M.; Fahl, U.

    2007-07-15

    Despite efforts to improve energy effi-ciency and increase the usage of renewable energy carriers, fossil fuels and nuclear energy will continue to be important sources of global energy supply for the coming decades. Present global oil and gas supply is characterized by a concentration of production in a few world areas, mainly the Middle East and the Former Soviet Union, and a transport from these regions to the industrialized countries. Depletion of conventional reserves, especially oil, in combination with a surge for energy in emerging economies, as China and India, how-ever, is expected to change this picture in the future: unconventional resources in other world regions may be exploited to cover the surge energy demand, infrastructure for energy transport along new routes may have to be established. To provide a data base for such ques-tions, this report gives an overview of the current global resource situation for coal, natural gas, oil and uranium. In the first part, an assessment of the con-ventional and unconventional reserves and resources as well as their supply costs is given for the different regions of the world. The second part describes the current energy trade infrastructure between world regions and estimates the costs for existing and new trade links between these regions. (orig.)

  3. Nondestructive analysis of the natural uranium mass through the measurement of delayed neutrons using the technique of pulsed neutron source; Analise nao destrutiva da massa de uranio natural atraves da medida de neutrons atrasados com o uso da tecnica de fonte pulsada de neutrons rapidos

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, Paulo Rogerio Pinto

    1979-07-01

    This work presents results of non destructive mass analysis of natural uranium by the pulsed source technique. Fissioning is produced by irradiating the test sample with pulses of 14 MeV neutrons and the uranium mass is calculated on a relative scale from the measured emission of delayed neutrons. Individual measurements were normalised against the integral counts of a scintillation detector measuring the 14 MeV neutron intensity. Delayed neutrons were measured using a specially constructed slab detector operated in anti synchronism with the fast pulsed source. The 14 MeV neutrons were produced via the T(d,n) {sup 4}He reaction using a 400 kV Van de Graaff accelerated operated at 200 kV in the pulsed source mode. Three types of sample were analysed, namely: discs of metallic uranium, pellets of sintered uranium oxide and plates of uranium aluminium alloy sandwiched between aluminium. These plates simulated those of Material Testing Reactor fuel elements. Results of measurements were reproducible to within an overall error in the range 1.6 to 3.9%; the specific error depending on the shape, size and mass of the sample. (author)

  4. The natural aging of austenitic stainless steels irradiated with fast neutrons

    Science.gov (United States)

    Rofman, O. V.; Maksimkin, O. P.; Tsay, K. V.; Koyanbayev, Ye. T.; Short, M. P.

    2018-02-01

    Much of today's research in nuclear materials relies heavily on archived, historical specimens, as neutron irradiation facilities become ever more scarce. These materials are subject to many processes of stress- and irradiation-induced microstructural evolution, including those during and after irradiation. The latter of these, referring to specimens "naturally aged" in ambient laboratory conditions, receives far less attention. The long and slow set of rare defect migration and interaction events during natural aging can significantly change material properties over decadal timescales. This paper presents the results of natural aging carried out over 15 years on austenitic stainless steels from a BN-350 fast breeder reactor, each with its own irradiation, stress state, and natural aging history. Natural aging is shown to significantly reduce hardness in these steels by 10-25% and partially alleviate stress-induced hardening over this timescale, showing that materials evolve back towards equilibrium even at such a low temperature. The results in this study have significant implications to any nuclear materials research program which uses historical specimens from previous irradiations, challenging the commonly held assumption that materials "on the shelf" do not evolve.

  5. Application of radiochemical-and direct gamma ray spectrometry methods for the determination of the burnup of irradiated uranium oxide

    International Nuclear Information System (INIS)

    Cunha, I.I.L.; Nastasi, M.J.C.; Lima, F.W. de

    1979-01-01

    The burn-up of U 3 O 8 (natural uranium) samples was determined by using both destructive and non-destructive methods, and comparing the results obtained. The radioisotopes 144 Ce, 103 Ru, 106 Ru, 137 Cs and 95 Zr were chosen as monitors. In order to isolate the radioisotopes chosen as monitors, a separation scheme has been established in which the solvent extraction technic is used to separate cerium, cesium, and ruthenium one from the other and from uranium. The separation between zirconium and niobium and of both from the others was accomplished by means of adsorption on a silica-gel column. When the non-destructive method was used, the radioactivity of each nuclide of interest was measured in the presence of all others. For this purpose, use was made of gamma-ray spectrometry and a Ge-Li detector. The comparison of burn-up values obtained by both destructive and non-destructive methods was made by means of Student's 't' test, and it has shown that the averages of results obtained in each case are equal. (Author) [pt

  6. Electron-trapping probability in natural dosemeters as a function of irradiation temperature

    DEFF Research Database (Denmark)

    Wallinga, J.; Murray, A.S.; Wintle, A.G.

    2002-01-01

    The electron-trapping probability in OSL traps as a function of irradiation temperature is investigated for sedimentary quartz and feldspar. A dependency was found for both minerals; this phenomenon could give rise to errors in dose estimation when the irradiation temperature used in laboratory...... procedures is different from that in the natural environment. No evidence was found for the existence of shallow trap saturation effects that Could give rise to a dose-rate dependency of electron trapping....

  7. Study on irradiation conditions of producing 153Sm with natural abundance samarium target

    International Nuclear Information System (INIS)

    Du Jin; Jin Xiaohai; Bai Hongsheng; Liu Yuemin; Chen Daming; Wang Fan

    1998-01-01

    Irradiation conditions of natural abundance 152 Sm targets in different forms are studied in the heavy water reactor and the light water swimming pool reactor at the China Institute of Atomic Energy. The result shows that the specific activity of 153 Sm in liquid form target irradiated in the light water swimming pool reactor is two times greater than that in solid form target. The radionuclide purity of 153 Sm is more than 99%, which can meet the needs of clinical application

  8. Batch scale storage of sprouting foods by irradiation combined with natural low temperature; pt. 1

    International Nuclear Information System (INIS)

    Cho, H.O.; Kwon, J.H.; Yang, H.S.; Byun, M.W.; Lee, C.H.

    1982-01-01

    In order to develop the commercial storage method of potatoes by irradiation combined with natural low temperature, two varieties of potatoes, Irish cobbler and Shimabara were stored at natural low temperature storage room (450x650x250cm; year round temperature change, 2-17 degC; 70-85% R.H.) on a batch scale followed by irradiation with optimum dose level. Irish cobbler and Shimabara were 100% sprouted after 3 months storage in control, whereas in 15Krad irradiated group, sprouting was completely inhibited at Irish cobbler for 9 months storage, and at Shimabara for 12 months. The extent of loss due to rot attack after 9 months storage was 6% in control, 6-8% in 10-15Krad irradiated group at Irish cobbler and weight loss was 16.5% in control, 5.1-5.6% in irradiated group, whereas rotting rate of Shimabara after 12 months storage was 100% in control, 15% in irradiated group and the weight loss of its was 12.6% in control, 7.3-7.4% in irradiated group. The moisture content in whole storage period of two varieties were 72-82% without remarkable changes. The total sugar and ascorbic acid contents were slightly decreased according to the dose increase and elapse of storage period, whereas reducing sugar content was increased. Irish cobbler was 90% markrtable after 9 months storage and 85% in Shimabara after 12 months storage. (Author)

  9. Malachite green adsorption onto natural zeolite and reuse by microwave irradiation

    International Nuclear Information System (INIS)

    Han Runping; Wang Yu; Sun Qing; Wang Lulu; Song Jiyun; He Xiaotian; Dou Chanchan

    2010-01-01

    Natural zeolite was used for the removal of malachite green (MG) from aqueous solution in batch mode and reused by microwave irradiation. The isotherm data were analyzed by the Langmuir, Freundlich, Redlich-Peterson, and Koble-Corrigan isotherm model. The better fit for the equilibrium process was Koble-Corrigan model. The kinetic studies indicated that the adsorption followed the pseudo-second-order kinetic. Thermodynamic calculations showed that the adsorption was spontaneous and endothermic process. Spent zeolite was treated by microwave irradiation and it was found that yield of regeneration was 85.8% in the case of microwave irradiated time 10 min at 160 W.

  10. Application and improvement of reciprocating-sieve plate extraction column in natural uranium extraction and purification process

    International Nuclear Information System (INIS)

    Wang Xuejun; Li Linyan; Liu Jing; Liu Xin; Yang Lifeng; Xiao Shaohua; Liu Hao

    2013-01-01

    Reciprocating-sieve plate extraction column is commonly used in the extraction process. Optimization and application were conducted successfully via production practice in some chemical and pharmaceutical plants, and good results are obtained while it is applied in the natural uranium extraction and purification process. The key component of reciprocating-sieve plate extraction column is gear-drive equipment in which drive motor serves as its core. Hence, it is important to select appropriate mode of speed regulation. In this paper, the principle and performance of several mode of speed regulation are compared. Both electromagnetic slip and frequency speed-regulation can be applied in general industrial process, but frequency speed-regulation with low energy cost can be used in wider operating range. The application of frequency speed-regulation mode used in reciprocating-sieve plate extraction column will increase the convenience and stability of natural uranium extraction and purification process. (authors)

  11. Radiation protection program applied to occupationally exposed individuals at the IPEN/CNEN-SP pilot plant in the 1980s for natural uranium compounds; Programa de radioproteção aplicado aos indivíduos ocupacionalmente expostos na usina piloto do IPEN-CNEN/SP na década de 80 para compostos de urânio natural

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Teresinha de Moraes da; Sordi, Gian Maria A.A.; Vasques, Francisco Mário Feijó, E-mail: tmsilva@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

    2017-07-01

    The work evidences the chemical processing of natural uranium from the yellowcake phase to the production of UF{sub 6} natural uranium hexafluoride, a process carried out at the IPEN/CNEN-SP pilot plant. Radiation protection management was intended to monitor occupationally exposed individuals - IOEs, the workplace and the environment. An individual monitoring program for IOEs was developed for both external irradiation and incorporation of radioactive material. The IOEs were monitored externally with film-type dosimeters and the in vitro method was applied internally for urine analysis. For the workplace the monitoring program for equipment and floors was developed, determining the exposure rate from the process equipment, surface contamination expressed in Bq.cm{sup -2} in equipment and floors, complemented by the air monitoring program both for the worker as well as for the workplace. Cellulose filters with aerodynamic diameter of 0.3 micron to 8.0 micron were used.

  12. Relative significance of natural irradiation vs all human exposures

    International Nuclear Information System (INIS)

    Jammet, H.

    1985-01-01

    A review is made of the fundamentals allowing to quantitatively express the importance of the various sources of human exposure by an individual or collective approach. Following a summary of the components of normal exposure to natural sources, the various human actions at the origin of enhanced exposure are studied: 1) those modifying the relationship between natural sources and man (dwelling conditions, coal burning, geothermal energy production, exploitation of phosphate rock); 2) those creating new artificial sources (nuclear explosions in the atmosphere, nuclear power production, medical use of radiation and radionuclides). The effective dose equivalent commitments for these sources are compared with those necessarily involved by continuous normal exposure to the natural sources of exposure [fr

  13. Measurement methods and optimization of radiation protection: the case of internal exposure by inhalation to natural uranium compounds

    International Nuclear Information System (INIS)

    Degrange, J.P.; Gibert, B.

    1998-01-01

    The aim of this presentation is to discuss the ability of different measurement methods (air sampling and biological examinations) to answer to demands in the particular case of internal exposure by inhalation to natural uranium compounds. The realism and the sensitivity of each method are studied, on the base of new dosimetric models of the ICRP. The ability of analysis of these methods in order to optimize radiation protection are then discussed. (N.C.)

  14. The Oklo natural nuclear reactors: neutron parameters, age and duration of the reactions, uranium and fission products migrations

    International Nuclear Information System (INIS)

    Ruffenach, J.-C.

    1979-09-01

    Mass spectrometry and isotopic dilution technique are used in order to carry out, on various samples from the fossil nuclear reactors at Oklo, Gabon, isotopic and chemical analyses of some particular elements involved in the nuclear reactions: uranium, lead, bismuth, thorium, rare gases (krypton, xenon), rare earths (neodymium, samarium, europium, gadolinium, dysprosium), ruthenium and palladium. Interpretations of these analyses lead to the determination of many neutron parameters such as the neutron fluence received by the samples, the spectrum index, the conversion coefficient, and also the percentages of fissions due to uranium-238 and plutonium-239 and the total number of fissions relative to uranium. All these results make it possible to determine the age of the nuclear reactions by measuring the amounts of fission rare earths formed, i.e. 1.97 billion years. This study brings some informations to the general problem of radioactive wastes storage in deep geological formations, the storage of uranium, plutonium and many fission products having been carried out naturally, and for about two billion years [fr

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

    International Nuclear Information System (INIS)

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

    1993-08-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-08-01

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

  17. Application of the radiochemical - and the direct gamma ray spectrometry method to the burnup determination of irradiated uranium oxide

    International Nuclear Information System (INIS)

    Cunha, I.I.L.

    1979-01-01

    The burn up of natural U 3 O 8 that occurs by the action of thermal neutrons was determined, using the radioisotopes 144 Ce, 137 Cs, 103 Ru, 106 Ru and 95 Zr as monitors. The determination of the burn up was made using both destructive and non-destructive methods. In the non-destructive method, the technique of direct gamma-ray spectrometry was used and the radioisotopes mentioned were simultaneously counted in a Ge-Li detector. In the radiochemical method the same radioisotopes were isolated one from the other and from all other fission products before counting. The solvent extraction technique was used for the radiochemical separation of uranium, cerium, cesium and ruthenium. To separate zirconium and niobium, adsorption in silica-gel was used. The extraction agent employed to isolate cesium was dipycrilamine and for the separation of the other radioisotopes Di-(2-Ethyl Hexyl) Phosphoric acid (HDEHP) was used. (Author) [pt

  18. Isochron measurements of naturally irradiated K-feldspar grains

    International Nuclear Information System (INIS)

    Li Bo; Li Shenghua; Wintle, Ann G.; Zhao Hui

    2007-01-01

    The equivalent doses of K-feldspar grains in a range of grain sizes from 90 to 250μm diameter were measured using a single-aliquot regenerative-dose protocol for the infrared stimulated luminescence (IRSL) signals for two samples of desert sand. The equivalent doses for each sample were compared with that for the 125-150μm grains of quartz from the same samples. The results suggested that the K-feldspar equivalent doses were underestimated because of anomalous fading. Measurements of the decay of the IRSL signals following laboratory irradiation for these two samples, and an additional one from a previously published isochron study, showed anomalous fading during the period of laboratory storage. The decay rate was about 3% per decade for all samples and was independent of the grain size used. Using plots of equivalent doses for K-feldspars as a function of their calculated internal dose rate, and the quartz equivalent dose as a function of grain size, it was concluded that the IRSL signal derived from the internal dose rate had not faded over the 13,000 years that had elapsed since the grains were deposited

  19. The influence of gamma irradiation on natural dyeing properties of cotton and flax fabrics

    Science.gov (United States)

    Chirila, Laura; Popescu, Alina; Cutrubinis, Mihalis; Stanculescu, Ioana; Moise, Valentin Ioan

    2018-04-01

    Fabrics made of 100% cotton and 100% flax respectively were exposed at ambient temperature to gamma radiation doses, from 5 to 40 kGy, using a Co-60 research irradiator. After the irradiation treatment the fabrics were subjected to dyeing process with Itodye Nat Pomegranate commercial natural dye. The influence of gamma irradiation treatment on the physical-mechanical properties, dyeing and surface morphology of natural fibres were investigated. Gamma ray treatment of 40 kGy was the most effective in the case of fabrics made from 100% cotton, enhancing the colour strength as evidenced by K/S value. The results obtained from the mechanical properties of fabrics made of 100% flax indicated that the dose of 40 kGy leads to a decrease of tensile strength up of to 41.5%. Infrared spectroscopy was used to monitor chemical and structural changes in cellulosic fibres induced during processing. Crystallinity indices calculated from various bands ratio showed insignificant variations for cotton and small variations in the case of flax. The surface morphology of irradiated cotton fabrics did not show significant changes even at the highest dose of 40 kGy, while the low doses applied on flax fabrics led to an appearance of small changes of surface morphology. The gamma irradiation increased the uptake of natural dyes on natural cellulosic fibres.

  20. Ultraviolet irradiation effects incorporation of nitrate and nitrite nitrogen into aquatic natural organic matter

    Science.gov (United States)

    Thorn, Kevin A.; Cox, Larry G.

    2012-01-01

    One of the concerns regarding the safety and efficacy of ultraviolet radiation for treatment of drinking water and wastewater is the fate of nitrate, particularly its photolysis to nitrite. In this study, 15N NMR was used to establish for the first time that UV irradiation effects the incorporation of nitrate and nitrite nitrogen into aquatic natural organic matter (NOM). Irradiation of 15N-labeled nitrate in aqueous solution with an unfiltered medium pressure mercury lamp resulted in the incorporation of nitrogen into Suwannee River NOM (SRNOM) via nitrosation and other reactions over a range of pH from approximately 3.2 to 8.0, both in the presence and absence of bicarbonate, confirming photonitrosation of the NOM. The major forms of the incorporated label include nitrosophenol, oxime/nitro, pyridine, nitrile, and amide nitrogens. Natural organic matter also catalyzed the reduction of nitrate to ammonia on irradiation. The nitrosophenol and oxime/nitro nitrogens were found to be susceptible to photodegradation on further irradiation when nitrate was removed from the system. At pH 7.5, unfiltered irradiation resulted in the incorporation of 15N-labeled nitrite into SRNOM in the form of amide, nitrile, and pyridine nitrogen. In the presence of bicarbonate at pH 7.4, Pyrex filtered (cutoff below 290–300 nm) irradiation also effected incorporation of nitrite into SRNOM as amide nitrogen. We speculate that nitrosation of NOM from the UV irradiation of nitrate also leads to production of nitrogen gas and nitrous oxide, a process that may be termed photo-chemodenitrification. Irradiation of SRNOM alone resulted in transformation or loss of naturally abundant heterocyclic nitrogens.

  1. Determination of natural alpha-emitting isotopes of uranium and thorium in environmental and geological samples

    International Nuclear Information System (INIS)

    Crespo, M.T.

    1996-01-01

    It is described the complete radiochemical procedure used for the determination of uranium and thorium isotopes in environmental and geological samples by alpha spectrometry. Source preparation methods, alpha-counting and spectral analysis are also included

  2. Application of acid dissolution and natural evaporation to wet cake containing uranium

    International Nuclear Information System (INIS)

    Kim, Kil J.; Kang, Il Sik; Shon, Jong S.; Hong, Kwon P.

    2005-01-01

    Chemical wastes containing small amounts of uranium cause environmental problems, if those wastes exceed the concentration of the EPA standard, 20 μg.. /L, and the concentrated sludge should be additionally dried and packaged into a drum, and categorized as a radioactive waste. Diphosil resin is developed to specifically remove actinides or multivalent metals. The immobilization technique is adopted to make a bead form of Diphosil by embedding into sodium alginate, and adsorption characteristics for uranium are reported for a simulated waste solution. In this study, acid dissolution is applied to dissolve uranium from the precipitates of sludge or the dewatered cake in the reduced volume of wastes solution, and removal characteristics of uranium is experimented. From the results, the most effective treatment method for the dissolved solution is suggested

  3. Conceptual design study on very small long-life gas cooled fast reactor using metallic natural Uranium-Zr as fuel cycle input

    International Nuclear Information System (INIS)

    Monado, F.; Permana, S.

    2013-01-01

    Full-text: A conceptual design study of very small 350 MWth Gas-cooled Fast Reactors with Helium coolant has been performed. In this study Modified CANDLE burn-up scheme was implemented to create small and long life fast reactors with natural Uranium as fuel cycle input. Such system can utilize natural Uranium resources efficiently without the necessity of enrichment plant or reprocessing plant. The core with metallic fuel based was subdivided into 10 regions with the same volume. The fresh Natural Uranium is initially put in region-1, after one cycle of 10 years of burn-up it is shifted to region-2 and the each region-1 is filled by fresh Natural Uranium fuel. This concept is basically applied to all axial regions. The reactor discharge burn-up is 31.8 % HM. From the neutronic point of view, this design is in compliance with good performance. (author)

  4. Conceptual design study on very small long-life gas cooled fast reactor using metallic natural Uranium-Zr as fuel cycle input

    International Nuclear Information System (INIS)

    Monado, Fiber; Ariani, Menik; Su'ud, Zaki; Waris, Abdul; Basar, Khairul; Permana, Sidik; Aziz, Ferhat; Sekimoto, Hiroshi

    2014-01-01

    A conceptual design study of very small 350 MWth Gas-cooled Fast Reactors with Helium coolant has been performed. In this study Modified CANDLE burn-up scheme was implemented to create small and long life fast reactors with natural Uranium as fuel cycle input. Such system can utilize natural Uranium resources efficiently without the necessity of enrichment plant or reprocessing plant. The core with metallic fuel based was subdivided into 10 regions with the same volume. The fresh Natural Uranium is initially put in region-1, after one cycle of 10 years of burn-up it is shifted to region-2 and the each region-1 is filled by fresh Natural Uranium fuel. This concept is basically applied to all axial regions. The reactor discharge burn-up is 31.8% HM. From the neutronic point of view, this design is in compliance with good performance

  5. Comparison of irradiation behavior of different uranium silicide dispersion fuel element designs

    International Nuclear Information System (INIS)

    Hofman, G.L.; Rest, J.; Snelgrove, J.L.

    1995-01-01

    Calculations of fuel swelling of U 3 SiAl-Al and U 3 Si 2 were performed for various dispersion fuel element designs. Breakaway swelling criteria in the form of critical fuel volume fractions were derived with data obtained from U 3 SiAl-Al plate irradiations. The results of the analysis show that rod-type elements remain well below the pillowing threshold. However, tubular fuel elements, which behave essentially like plates, will likely develop pillows or blisters at around 90% 235 U burnup. The U 3 Si 2 -Al compounds demonstrate stable swelling behavior throughout the entire burnup range for all fuel element designs

  6. A solvent proceed for the extraction of the irradiate uranium and plutonium in the reactor core; Un procede par solvant pour l'extraction du plutonium de l'uranium irradie dans les piles

    Energy Technology Data Exchange (ETDEWEB)

    Goldschmidt, B; Regnaut, P; Prevot, I [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1955-07-01

    Description of the conditions of plutonium, fission products and of uranium separation by selective extraction of the nitrates by organic solvent, containing a simultaneous extraction of plutonium and uranium, followed by a plutonium re-extraction after reduction, and an uranium re-extraction. The rates of decontamination being insufficient in this first stage, we also describes the processes of decontamination permitting separately to get the rates wanted for uranium and plutonium. Finally, we describes the beginning of the operation that consists in a nitric dissolution of the active uranium while capturing the products of gaseous fission, as well as the final concentration of the products of fission in a concentrated solution. (authors) [French] Description des conditions de separation du plutonium, des produits de fission et de l'uranium au moyen d'une extraction selective des nitrates par solvant organique, comprenant une extraction simultanee du plutonium et de l'uranium, suivie d'une reextraction du plutonium apres reduction, et d'une reextraction de l'uranium. Les taux de decontamination etant insuffisants dans ce premier stade, on decrit egalement les processus de decontamination permettant separement d'obtenir les taux desires pour l'uranium et le plutonium. Enfin, on decrit aussi le debut de l'operation qui consiste en une dissolution nitrique de l'uranium actif en captant les produits de fission gazeux, ainsi que la concentration finale des produits de fission sous forme de solution concentree. (auteurs)

  7. Effects of ultraviolet irradiation on natural killer cell function in systemic lupus erythematosus

    Energy Technology Data Exchange (ETDEWEB)

    Nived, O.; Johansson, I.; Sturfelt, G. (University Hospital, Lund (Sweden). Dept. of Rheumatology)

    1992-06-01

    In vitro irradiation with long wavelength ultraviolet light (UV-A), in clinically relevant dosages, of a natural killer cell line containing cell preparations from 17 control subjects reduced natural killer cell cytotoxicity with the cell line K562 as target. The spontaneous function of natural killer cells from 12 patients with systematic lupus erythematosus (SLE) correlated inversely with the one hour erythrocyte sedimentation rate, but not with glucocorticoid doses. After UV-A exposure, natural killer cells from patients with SLE exert either increased or decreased cytotoxicity, and the direction of change is inversely correlated with the spontaneous natural killer cell function. (Author).

  8. Effects of ultraviolet irradiation on natural killer cell function in systemic lupus erythematosus

    International Nuclear Information System (INIS)

    Nived, O.; Johansson, I.; Sturfelt, G.

    1992-01-01

    In vitro irradiation with long wavelength ultraviolet light (UV-A), in clinically relevant dosages, of a natural killer cell line containing cell preparations from 17 control subjects reduced natural killer cell cytotoxicity with the cell line K562 as target. The spontaneous function of natural killer cells from 12 patients with systematic lupus erythematosus (SLE) correlated inversely with the one hour erythrocyte sedimentation rate, but not with glucocorticoid doses. After UV-A exposure, natural killer cells from patients with SLE exert either increased or decreased cytotoxicity, and the direction of change is inversely correlated with the spontaneous natural killer cell function. (Author)

  9. Effect of gamma radiation dose and sensitizer on the physical properties of irradiated natural rubber latex

    International Nuclear Information System (INIS)

    Komgrit, R.; Thawat, C.; B, Tripob; Wirach, T.

    2009-07-01

    Full text: The vulcanization of natural rubber latex can be induced by gamma radiation, which enhances cross-linking within the rubber matrix. The purpose of this research is to investigate the effect of gamma radiation dose and sensitizers on the physical properties of irradiated natural rubber. Three sensitizers n-butyl acrylate (n-B A), tetrachloroethylene (C 2 Cl 4 ) and trichloromethane (CHCl 3 ) were mixed with natural rubber latex before irradiation with gamma ray dose varied from 14 to 22 kGy. Results showed that the mixture of three sensitizers with specific ratios effectively induced the cross-linking of natural rubber latex. The cross-linking ratio and improved physical properties increased with increasing gamma dose. Therefore, the mixture ratios of n-B A, C 2 Cl 4 and CHCl 3 have shown to be a critical parameter in the vulcanization of natural rubber latex by gamma radiation

  10. XRD monitoring of α self-irradiation in uranium-americium mixed oxides.

    Science.gov (United States)

    Horlait, Denis; Lebreton, Florent; Roussel, Pascal; Delahaye, Thibaud

    2013-12-16

    The structural evolution under (241)Am self-irradiation of U(1-x)Am(x)O(2±δ) transmutation fuels (with x ≤ 0.5) was studied by X-ray diffraction (XRD). Samples first underwent a preliminary heat treatment performed under a reducing atmosphere (Ar/H2(4%)) aiming to recover the previously accumulated structural defects. Over all measurements (carried out over up to a full year and for integrated doses up to 1.5 × 10(18) α-decay events·g(-1)), only fluorite U(1-x)Am(x)O(2±δ) solid solutions were observed. Within a few days after the end of the heat treatment, each of the five studied samples was slowly oxidized as a consequence of their move to air atmosphere, which is evidenced by XRD by an initial sharp decrease of the unit cell parameter. For the compounds with x ≤ 0.15, this oxidation occurred without any phase transitions, but for U0.6Am0.4O(2±δ) and U0.5Am0.5O(2±δ), this process is accompanied by a transition from a first fluorite solid solution to a second oxidized one, as the latter is thermodynamically stable in ambient conditions. In the meantime and after the oxidation process, (241)Am α self-irradiation caused a structural swelling up to ∼0.8 vol %, independently of the sample composition. The kinetic constants of swelling were also determined by regression of experimental data and are, as expected, dependent on x and thus on the dose rate. The normalization of these kinetic constants by sample α-activity, however, leads to very close swelling rates among the samples. Finally, evolutions of microstrain and crystallite size were also monitored, but for the considered dose rates and cumulated doses, α self-irradiation was found, within the limits of the diffractometer used, to have almost no impact on these characteristics. Microstrain was found to be influenced instead by the americium content in the materials (i.e., by the impurities associated with americium starting material and the increase of cationic charge heterogeneity with

  11. Irradiation techniques for the release of bound heavy metals in natural waters and blood

    International Nuclear Information System (INIS)

    Batley, G.E.; Farrar, Y.J.

    1978-01-01

    Irradiation techniques are compared with conventional acid digestion procedures for the release of bound heavy metals in natural waters and in blood, before their determination by anodic stripping voltammetry. Ultra-violet irradiation of acidified water with a 550-W mercury vapour lamp releases bound zinc, cadmium, lead and copper after 4 h. The same results can be achieved with a 30 Mrad dose of high-energy γ-irradiation. These techniques are also effective for the release of metals in whole blood and blood plasma, where sample volumes as small as 200 μl are adequate in analyses for zinc, copper and lead. By comparison with acid digestion and solvent extraction methods, irradiation treatments offer the advantages of minimum sample manipulation and negligible reagent blanks. (Auth.)

  12. Natural rubber/high density polyethylene/ground rubber composites vulcanized by gamma irradiation

    International Nuclear Information System (INIS)

    Shaltout, N.A.; Abou zeid, M.M.; Khalil, A.M.; El Miligy, A.A.

    2010-01-01

    Natural rubber (NR) was blended mechanically with 50 phr high density polyethylene (HDPE). the mechanical, physical and thermal properties of NR/HDPE blend and its composites with different contents of ground tire rubber (GTR) before and after exposure to gamma irradiation to various doses up to 250 kGy were studied. Also, the change in structure morphology of irradiated NR/HDPE blend as well as NR/HDPE/GTR composites was examined by scanning electron microscope (SEM). The results showed that the substitution of a part of virgin NR with GTR decreases the mechanical and physical properties but not to the extent of deterioration . However, it was found that the mechanical and physical properties were improved after gamma irradiation . Composite of NR/GTR/HDPE (75/25/50) showed good properties. Scanning electron microscope showed homogeneity between the irradiated composites ingredients.

  13. Modeling the natural UV irradiation and comparative UV measurements at Moussala BEO (BG)

    Science.gov (United States)

    Tyutyundzhiev, N.; Angelov, Ch; Lovchinov, K.; Nitchev, Hr; Petrov, M.; Arsov, T.

    2018-03-01

    Studies of and modeling the impact of natural UV irradiation on the human population are of significant importance for human activity and economics. The sharp increase of environmental problems – extraordinary temperature changes, solar irradiation abnormalities, icy rains – raises the question of developing novel means of assessing and predicting potential UV effects. In this paper, we discuss new UV irradiation modeling based on recent real-time measurements at Moussala Basic Environmental Observatory (BEO) on Moussala Peak (2925 m ASL) in Rila Mountain, Bulgaria, and highlight the development and initial validation of portable embedded devices for UV-A, UV-B monitoring using open-source software architecture, narrow bandpass UV sensors, and the popular Arduino controllers. Despite the high temporal resolution of the VIS and UV irradiation measurements, the results obtained reveal the need of new assumptions in order to minimize the discrepancy with available databases.

  14. Optimisation of cancer chemotherapy or irradiation therapy by natural biological extracts

    International Nuclear Information System (INIS)

    Uray, Z.; Abraham, S.; Bara, A.; Laszlo, G.; Radulescu, E.; Maniu, M.; Camelia, B.

    1993-01-01

    Authors report on the adjuvant efficiency of fetal calf thymus extract (Leukotrofina, Ellem, Italy) and Fetal calf spleen extract (Trofapar, Biofarm, Roumania) in rats after cyclophosphamide treatment (3*40 mg/kg/day) and whole-body irradiation (3.5 Gy), respectively. Morphological and functional damages of the myeloid system upon chemotherapy or irradiation were efficiently protected by both extracts, as demonstrated by the rapid recovery of impaired iron-incorporation, cell proliferatrion, blood-count and cell morphology. Irregular oxygen consumption, cholesterol level or ascorbic acid concentration, indicating the damages of hepatic and adrenal metabolic functions following chemotherapy or irradiation, were also efficiently neutralized by the extracts studied. These experimental data support suitability, as potent adjuvant agents, of these bioactive natural preparations for cancer chemotherapy or irradiation therapy. (author) 8 refs.; 6 tabs

  15. Simultaneous determination of RA-226, natural uranium and natural thorioum by gamma-ray spectrometry INa(Tl) in solid samples

    International Nuclear Information System (INIS)

    Salvador, S.; Navarro, T.; Alvarez, A.

    1990-01-01

    A method has been described to determine activities of Ra-226, natural uranium, and natural thorium, by gamma-ray spectrometry. The system was calibrated for efficiency by using synthetic calibrated standards. It is necessary, in the samples, to assume secular equilibrium between Ra-226 and Th-232 and its daughters nuclides, and U-238 and its immediate daughter Th-234, because the photopeaks measured are from these dsaugthers. Our results indicate that a non destructive gamma spectrometric method can ofter replace the radiochemical techniques used in measuring radiactivities in this type of samples. (Author). 9 refs

  16. Electron beam irradiation in natural fibres reinforced polymers (NFRP)

    Energy Technology Data Exchange (ETDEWEB)

    Kechaou, B. [LaMaCoP - Faculte des sciences de Sfax, 3018 Sfax (Tunisia); LTDS-UMR 5513 - Ecole Centrale de Lyon, B.P 163 69134 Ecully Cedex (France); Salvia, M. [LTDS-UMR 5513 - Ecole Centrale de Lyon, B.P 163 69134 Ecully Cedex (France); Fakhfakh, Z. [LaMaCoP - Faculte des sciences de Sfax, 3018 Sfax (Tunisia); Juve, D. [LTDS-UMR 5513 - Ecole Centrale de Lyon, B.P 163 69134 Ecully Cedex (France); Boufi, S. [LSME-Faculte des Sciences de Sfax, 3018 Sfax (Tunisia); Kallel, A. [LaMaCoP - Faculte des sciences de Sfax, 3018 Sfax (Tunisia); Treheux, D. [LTDS-UMR 5513 - Ecole Centrale de Lyon, B.P 163 69134 Ecully Cedex (France)], E-mail: daniel.treheux@ec-lyon.fr

    2008-11-15

    This study focuses on the electric charge motion in unsatured polyester and epoxy composites reinforced by natural fibres of Alfa type, treated by different coupling agents. The electric charging phenomenon is studied by scanning electron microscopy mirror effect (SEMME) coupled with the induced current method (ICM). Previously, using the same approach, glass fibre reinforced epoxy (GFRE) was studied to correlate mechanical [B. Kchaou, C. Turki, M. Salvia, Z. Fakhfakh, D. Treheux, Composites Science and Technology 64 (2004) 1467], or tribological [B. Kchaou, C. Turki, M. Salvia, Z. Fakhfakh, D. Treheux, Dielectric and friction behaviour of unidirectionalglass fibre reinforced epoxy (GFRE), Wear, 265 (2008) 763.] properties and dielectric properties. It was shown that the dielectric properties of the fibre-matrix interfaces play a significant role in the optimization of the composite. This result seems to be the same for natural fibre composites: the fibre-matrix interfaces allow a diffusion of the electric charges which can delocalize the polarization energy and consequently delay the damage of the composite. However, a non-suited sizing can lead to a new trapping of electric charges along these same interfaces with, as a consequence, a localization of the polarisation energy. The optimum composite is obtained for one sizing which helps, at the same time, to have a strong fibre-matrix adhesion and an easy flow of the electric charges along the interface.

  17. Naturally occurring radionuclides transfer factor on aquatic flora and fauna in Nagarjuna Sagar Dam near proposed uranium mining site

    International Nuclear Information System (INIS)

    Arunachalam, Kantha Deivi

    2015-04-01

    Naturally occurring radioactive element can be found in low levels within all rock, soil, and water. The present work aims to understand the transfer of naturally occurring radionuclides in different compartments of environment reflecting its behaviour in different tropic levels. The understanding and evaluation of the possible interactions of various naturally occurring radionuclides were done in the world's third largest man-made dam, Nagarjuna Sagar, built on river Krishna located in Andhra Pradesh, India. The naturally occurring radionuclides such as Uranium ( 238 U), Polonium ( 210 Po), Radium ( 226 Ra), and Lead ( 210 Pb) were analyzed in different matrices (i.e) sediment, water, and fish. The measurement of the naturally occurring radionuclides in the environment can be used as a reference baseline for long-term monitoring in the entire aquatic ecosystem

  18. Investigation of spatial distribution of fission-rate of natural uranium nuclei in the blanket of electronuclear setup 'Energy plus Transmutation' at Dubna Nuclotron proton beam at energy 1.5 GeV

    International Nuclear Information System (INIS)

    Hashemi-Nezhad, S.R.; Zhuk, I.V.; Kievets, M.; Krivopustov, M.I.; Sosnin, A.N.; Westmeier, W.; Brandt, R.

    2008-01-01

    The 'Energy plus Transmutation' experimental setup of the Veksler and Baldin Laboratory of High Energy Physics within the Joint Institute for Nuclear Research (JINR) in Dubna, Russia, is a lead target (with a diameter of 8.4 cm and length of 45.6 cm) surrounded by a uranium blanket (weight 206.4 kg of natural uranium). A polyethylene plus cadmium shield is placed around the target-blanket assembly to modify the spallation and fission neutron spectra in the system. The setup was irradiated by a proton beam of energy 1.5 GeV using the Nuclotron accelerator. The spatial distribution of natural uranium fission-rate in the assembly and fission-rate in the blanket was determined experimentally and compared with Monte Carlo predictions using the MCNPX 2.6C code. Besides neutron-induced fission the calculations include the Nat U(p,f), Nat U(π,f) as well as Nat U(γ,f) reactions. Good agreement between the experimental and calculation results was obtained. The possible sources of errors in the experiment and calculations are discussed in detail

  19. Imprints left by natural radioactivity in geological materials: uranium fission tracks and thermoluminescence applications in earth sciences

    International Nuclear Information System (INIS)

    Broquet, P.; Chambaudet, A.; Rebetez, M.; Charlet, J.M.

    1994-01-01

    In a rock, all minerals which contain uranium are host to a number of spontaneous fission phenomena forming a single damaged area called a ''latent track'', observations of which may lead to dating, uranium mapping and finding paleo-geo-thermometers (thermal history, used in oil exploration). The radioactive elements during the decay process release energy which is trapped as electrons into the physical or chemical defects of the crystalline lattice; this energy can be later released by heating the mineral (thermic stimulated luminescence); the thermoluminescence is characterized by a glow which spectrum constitutes a typical feature of the mineral, its crystallization conditions and the subsequent evolution of the material. Natural and induced glow curve may be produced. 6 figs., 52 refs

  20. Method of preparation of uranium nitride

    Science.gov (United States)

    Kiplinger, Jaqueline Loetsch; Thomson, Robert Kenneth James

    2013-07-09

    Method for producing terminal uranium nitride complexes comprising providing a suitable starting material comprising uranium; oxidizing the starting material with a suitable oxidant to produce one or more uranium(IV)-azide complexes; and, sufficiently irradiating the uranium(IV)-azide complexes to produce the terminal uranium nitride complexes.

  1. Improving the lipid stability and sensory characteristics of irradiated minced beef by using natural herbal extracts

    International Nuclear Information System (INIS)

    Mansour, H. A.; Moliarned, H.M.; El-Niely, H.F.G.

    2007-01-01

    The objective of the present work was to use natural herbal extracts to minimize lipid oxidation and improve the sensory characteristics of irradiated minced beef. Beef longissimus dorsi were minced, mixed with herbal extracts as appropriate and packed in polyethylene bags (50 g each). There were four treatment groups: (1) untreated controls, (2) irradiated with cobalt-60 gamma-rays to either 2 or 4.5 kGy, (3) addition of extracts of one of marjoram, rosemary or sage to a final concentration of 0.04 % (v/w), (4) combination treatment with either 2 or 4.5 kGy irradiation, plus herbal extract at 0.04 % (v/w) added pre-irradiation. Aerobically packaged samples were then placed into storage at 5 degree C. At specified time intervals samples were withdrawn to be analyzed for thiobarbituric acid reactive substances (TEARS), sensory characteristics and psychrotrophic bacterial counts, Results demonstrated a significant benefit of the addition of herbal extracts to the minced beef prior to irradiation. All three extracts generally lowered the TBARS values in both control and irradiated samples, with marjoram being the most effective, followed by sage and rosemary in that order of efficacy. As regards radiation effected off-odour, all three extracts generally lowered the off-odour score, with marjoram and sage being most effective, and rosemary being somewhat less so. All three extracts protected against radiation effected colour loss. Addition of herbal extracts prior to irradiation resulted in significant increase (p< 0.05) in the acceptability scores for all irradiated samples in the post-irradiation period, with rosemary being somewhat less effective than sage and marjoram. Addition of herbal extracts alone to the minced meat did not affect the psychrotrophic bacterial counts of treated samples. The combination treatment with herbal extracts plus

  2. Changes of natural killer activity following local 60Co irradiation in intracranial tumor-bearing mice

    International Nuclear Information System (INIS)

    Otsuka, Shin-ichi; Suda, Kinya; Yamashita, Junkoh; Takeuchi, Juji; Handa, Hajime

    1982-01-01

    Changes of natural killer activity (NK activity) by local 60 Co irradiation in intracranial tumor-bearing mice were studied by the method of 51 Cr release assay. Local irradiation was administered 10 days after intracranial transplantation of 203-Glioma which had been originally induced by 20-methylcholanthrene in C57BL mice. Irradiation suppressed the growth of tumor and prolonged the mean survival time. The 50% survival time of untreated mice was about 2.5 weeks but that of mice treated by a single dose of 1000 rad and 1500 rad of irradiation was about 4.5 weeks and 6.5 weeks respectively. NK activity of spleen cells in these mice was serially examined. NK activity was gradually increased in mice treated by local irradiation, while it was gradually decreased in mice without treatment. On the other hand, NK activity remained unchanged in non-tumor-bearing control mice. Mice treated with 1000 rad and 1500 rad of irradiation showed 44.0% and 47.6% of % specific 51 Cr release respectively 11 days after irradiation while normal mice showed 18.0%. The increased NK activity after local irradiation suggested that local irradiation might have enhanced the immunological defence mechanisms against the tumor in the tumor-bearing hosts. Some characteristics of effector cells in this assay system were examined. The cytotoxicity of spleen cells was removed by the treatment of anti-BAT serum and complement but was not removed by the treatment of anti-Thy-1.2 serum and complement. Since NK activity reflects the immunological resistance to tumors to some extent, it is felt important to clarify the significance of changes of NK activity in patients with brain tumors in relation to various treatments including surgery, radiotherapy, chemotherapy and immunotherapy in the next step. (author)

  3. Fracture-filling minerals as uranium sinks and sources, a natural analogue study at Palmottu, Finland

    International Nuclear Information System (INIS)

    Cui, D.; Eriksen, T.

    2000-01-01

    The nucleation of a mineral crystal and its growth in groundwater carrying fractures 300 m above the Palmottu uranium deposit provide an impressive example of geochemical selectivity of uranium. Fracture-filling material was collected from a 3 mm thick fracture at depth 74.8-75 m (drillcore R348). SEM and EDS analyses on a thin section of the original fracture-filling show that the fracture filling is heterogeneous, composing mineral crystal particles and very porous clay-rich aggregates. The results of INAA on millimetre-sized single mineral crystals and aggregates selected from grinded fracture-filling show that porous aggregates (composed of clays and micrometer sized mineral particles) contain up to 1000 ppm U, which is higher than the average of the whole fracture-filling (400 ppm) and host rock related millimetre sized mineral particles (18-100 ppm). 233 U/ 238 U isotope exchange proves that a large fraction of the uranium in the fracture-filling is not easily exchanged with uranium in the solution. The amount of 238 U released in the isotope exchange experiment is too high to be explained by reversible U(VI) sorption. Oxidation state analyses show that 30% of the uranium exists as U(IV). Laboratory batch experiment at anoxic conditions proved that pyrite can immobilise U(VI). (orig.)

  4. Analysis of Gel Permeation Chromatography From Irradiation Copolymer Grafting of Methylmethacrylate on to Natural Rubber

    International Nuclear Information System (INIS)

    Hendrana, Sunit; Purwanto, Indratmoko Hari; Karyaningsih, Ipit; Utama, MargaHerwinarni

    2004-01-01

    Grafting of methyl methacrylate (MMA) onto natural rubber was carried out by γ-irradiation using 60 Co source at dose rate 1 KGy/h and total dose of 5 KGy. Gel permeation chromatography (GPC) was used to analyse the grafting. The GPC's chromatogram, molecular weight and molecular weight distribution data indicate that grafting of MMA onto natural rubber and homo polymerization of MMA are the reaction mostly occurs. Meanwhile, the presence of natural rubber radical with a chain end natural rubber radical affect the PMMA homopolymer occurred

  5. Determination of natural uranium in urine ({sup 233}U); Dosage de l'uranium dans l'urine ({sup 233}U)

    Energy Technology Data Exchange (ETDEWEB)

    Jeanmaire, L; Jammet, H [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1959-07-01

    A procedure for the quantitative analysis of uranium in urine is described. The residue obtained by mineralization is dissolved in diluted hydrochloric acid. Uranium is separated by fixation on a permutit 50 column, elution with 0,2 M oxalic acid and electrodeposition on nickel. Uranium is then measured by {alpha} counting. It is thus possible to detect less than 1 pico-curie of uranium in the sample. (author) [French] Cet article decrit une technique de dosage de l'uranium dans l'urine. Apres mineralisation, le residu est dissous dans l'acide chlorhydrique dilue. L'uranium est separe par fixation, sur une colonne de permutite 50, elution au moyen d'acide oxalique 0,2 M et depot electrolytique sur nickel. La mesure faite par comptage {alpha} permet de detecter moins de 1 picocurie d'uranium dans l'echantillon. (auteur)

  6. Cytogenetic analysis of the effect of chronic irradiation on natural Vicia Cracca L. populations

    International Nuclear Information System (INIS)

    Bondar', L.M.; Popova, O.N.; AN SSSR, Syktyvkar

    1989-01-01

    The study of microsporogenesis in Vicia cracca L. from chronically irradiated natural populations has demonstrated an increased number of wholly or partially sterile buds and reduced and damaged anthers. Both the number and the spectrum of chromosome and cell pathology increasing radiation dose, the exposed plants exhibiting meiosis disturbances that are not found in the controls

  7. Application of magnetic circular dichroism spectroscopy to the optical spectra of natural and irradiated diamonds

    International Nuclear Information System (INIS)

    Douglas, I.N.; Ruciman, W.A.; Australian National Univ., Canberra. Research School of Physical Sciences)

    1977-01-01

    The MCD spectra of natural type Ia and electron-irradiated type Ia and type IIa diamonds have been measured. The information obtained from MCD spectroscopy complements that obtained from absorption spectroscopy and can be helpful in the assignment of electronic transitions. (orig.) [de

  8. Treatment of uranium ores by natural leaching in Portugal; Traitement par lixiviation naturelle des minerais uraniferes portugais

    Energy Technology Data Exchange (ETDEWEB)

    Lacerda, J de [Junta de Energia Nuclear, Lisbonne (Portugal)

    1967-06-15

    The technique described for treating uranium ores by natural leaching has been developed as a result of research carried out in Portugal with a view to determining and eliminating the causes of uranium migration in ores stored in the open. With the natural leaching method, which has been successfully applied to primary uranium ores, the ore is piled up on a waterproof surface and sprayed intermittently with mine water. Pyrite and ferrous sulphate are used as solid reagents and are mixed with the ore in amounts averaging 0.4% and 0.2% respectively. Over 70 000 tons of ore with a U{sub 3}O{sub 8} content of between 0.076 and 0.150% have been treated at five natural leaching plants. The average recovery in these operations was between 57.7 and 85.9%. The average cost was US $3.31/lb U{sub 3}O{sub 8}. (author) [French] Le traitement des minerais uraniferes par lixiviation naturelle est le fruit des recherches effectuees au Portugal dans le but de determiner et d'eliminer les causes de la migration de l'uranium contenu dans les minerais emmagasines a ciel ouvert. La methode de lixiviation naturelle, appliquee avec succes aux mineraux primaires d'uranium, consiste essentiellement en l'arrosage intermittent, avec l'eau des mines, du minerai entasse sur des aires impermeabilisees. On utilise comme reactifs solides la pyrite et le sulfate ferreux melanges avec le minerai a raison de 0,4% et 0,2% respectivement en moyenne. Plus de 70 000 t de minerai, dont les teneurs en U{sub 3}O{sub 8} etaient comprises entre 0,076% et 0,150%, ont ete traitees dans cinq installations de lixiviation naturelle ou on a obtenu des recuperations moyennes oscillant entre 57,7% et 85,9%, pour le prix de revient moyen de 3,31 dollars par livre de U{sub 3}O{sub 8}. (author)

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

    International Nuclear Information System (INIS)

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

    1993-01-01

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

  10. Reactor AQUILON. The hardening of neutron spectrum in natural uranium rods, with a computation of epithermal fissions (1961); Pile AQUILON. Durcissement du spectre des neutrons dans les barreaux d'uranium et calcul des fissions epithermiques (1961)

    Energy Technology Data Exchange (ETDEWEB)

    Durand -Smet, R; Lourme, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1961-07-01

    - Microscopic flux measurements in reactor Aquilon have allowed to investigate the thermal and epithermal flux distribution in natural uranium rods, then to obtain the neutron spectrum variations in uranium, Wescott '{beta}' term of the average spectrum in the rod, and the ratio of epithermal to therma fissions. A new definition for the infinite multiplication factor is proposed in annex, which takes into account epithermal parameters. (authors) [French] - Un certain nombre de mesures effectuees dans la pile Aquilon ont permis d'etablir la distribution fine des flux thermique et epithermique dans les barreaux d'uranium, et d'en deduire les variations du spectre des neutrons dans l'uranium, le terme {beta} du spectre de Wescott moyen dans le barreau et le nombre de fissions epithermiques. En annexe, il est propose une definition nouvelle du coefficient de multiplication infini, qui fait intervenir les parametres epithermiques. (auteurs)

  11. Method of gradual acid leaching of uranium ores of silicate and aluminosilicate nature

    International Nuclear Information System (INIS)

    Bosina, B.; Krepelka, J.; Urban, P.; Kropacek, J.; Stransky, J.

    1987-01-01

    Leaching uranium ore pulp is divided into two stages. The first stage takes place without any addition of a leaching agent at elevated pressure and temperature. In the second stage, sulfuric acid is added to the pulp (50 to 1000 kg per tonne of ore) or an oxidation agent. Leaching then proceeds according to routine procedures. The procedure is used to advantage for silicate or aluminosilicate ores which contain uranium minerals which are difficult to leach, pyrite and reducing substances. The two stage leaching allows to use the technology of pressure leaching, reduces consumption of sulfuric acid and oxidation agents and still achieves the required reduction oxidation potential. (E.S.)

  12. Use of scattered media to determine lanthanides and actinides in natural water: application to uranium

    International Nuclear Information System (INIS)

    Reiller, P.

    1993-11-01

    This thesis has three parts; in the first one we present the general knowledge necessary to the understanding of phenomena to which we are going to be confronted: analysis by laser spectrofluorimetry with temporal resolution, chemistry in aqueous solution of uranium, fluorescence properties of uranium, chemistry of surfactants and their appliance in fluorescence exaltation; principle of ultrafiltration and application to ultrafiltration assisted by micella. In the second part, we will study the spectral and temporal properties of fluorescence with surfactants in the framework of using laser spectrofluorimetry with temporal resolution. In the last part, we will interest in the coupling of spectrofluorimetry and ultrafiltration assisted by micella

  13. Study of the oocyte degenerescence at mouse: role of the caspases and toxicity of natural uranium

    International Nuclear Information System (INIS)

    Arnault, E.

    2008-04-01

    The aim of this work is to estimate the uranium toxicity on the ovarian function and on the oocyte and more fundamentally to characterize the molecular ways regulating the oocyte degenerescence. At first, will be described the different exposure modes at uranium and the known toxic effects of this heavy metal on man and animal. The mechanisms regulating the follicle genesis and the oogenesis are then developed. At last, will be given the data available in literature and concerning the apoptosis ways intervening in the follicular atresia and in the oocyte degenerescence while referring to the known ways of the somatic cells. (O.M.)

  14. Irradiated KHYG-1 retains cytotoxicity: potential for adoptive immunotherapy with a natural killer cell line.

    Science.gov (United States)

    Suck, G; Branch, D R; Keating, A

    2006-05-01

    To evaluate gamma-irradiation on KHYG-1, a highly cytotoxic natural killer (NK) cell line and potential candidate for cancer immunotherapy. The NK cell line KHYG-1 was irradiated at 1 gray (Gy) to 50 Gy with gamma-irradiation, and evaluated for cell proliferation, cell survival, and cytotoxicity against tumor targets. We showed that a dose of at least 10 Gy was sufficient to inhibit proliferation of KHYG-1 within the first day but not its cytolytic activity. While 50 Gy had an apoptotic effect in the first hours after irradiation, the killing of K562 and HL60 targets was not different from non-irradiated cells but was reduced for the Ph + myeloid leukemia lines, EM-2 and EM-3. gamma-irradiation (at least 10 Gy) of KHYG-1 inhibits cell proliferation but does not diminish its enhanced cytolytic activity against several tumor targets. This study suggests that KHYG-1 may be a feasible immunotherapeutic agent in the treatment of cancers.

  15. Impact of uranyl-calcium-carbonato complexes on uranium(VI) adsorption to synthetic and natural sediments.

    Science.gov (United States)

    Stewart, Brandy D; Mayes, Melanie A; Fendorf, Scott

    2010-02-01

    Adsorption on soil and sediment solids may decrease aqueous uranium concentrations and limit its propensity for migration in natural and contaminated settings. Uranium adsorption will be controlled in large part by its aqueous speciation, with a particular dependence on the presence of dissolved calcium and carbonate. Here we quantify the impact of uranyl speciation on adsorption to both goethite and sediments from the Hanford Clastic Dike and Oak Ridge Melton Branch Ridgetop formations. Hanford sediments were preconditioned with sodium acetate and acetic acid to remove carbonate grains, and Ca and carbonate were reintroduced at defined levels to provide a range of aqueous uranyl species. U(VI) adsorption is directly linked to UO(2)(2+) speciation, with the extent of retention decreasing with formation of ternary uranyl-calcium-carbonato species. Adsorption isotherms under the conditions studied are linear, and K(d) values decrease from 48 to 17 L kg(-1) for goethite, from 64 to 29 L kg (-1) for Hanford sediments, and from 95 to 51 L kg(-1) for Melton Branch sediments as the Ca concentration increases from 0 to 1 mM at pH 7. Our observations reveal that, in carbonate-bearing waters, neutral to slightly acidic pH values ( approximately 5) and limited dissolved calcium are optimal for uranium adsorption.

  16. Natural radioactivity measurements and dose calculations to the public: Case of the uranium-bearing region of Poli in Cameroon

    International Nuclear Information System (INIS)

    Saidou; Bochud, Francois O.; Baechler, Sebastien; Moise, Kwato Njock; Merlin, Ngachin; Froidevaux, Pascal

    2011-01-01

    The objective of this work is to carry out a baseline study of the uranium-bearing region of Poli in which lies the uranium deposit of Kitongo, prior to its impending exploitation. This study required sampling soil, water and foodstuffs representative of the radioactivity exposure and food consumption patterns of the population of Poli. After sampling and radioactivity measurements were taken, our results indicated that the activities of natural series in soil and water samples are low. However, high levels of 210 Po and 210 Pb in foodstuffs (vegetables) were discovered and elevated activities of 40 K were observed in some soil samples. All components of the total dose were assessed and lead to an average value of 5.2 mSv/year, slightly higher than the average worldwide value of 2.4 mSv/year. Most of this dose is attributable to the ingestion dose caused by the high levels of 210 Po and 210 Pb contained in vegetables, food items which constitute an important part of the diet in Northern Cameroon. Consequently, bringing uranium ore from underground to the surface might lead to an increased dose for the population of Poli through a higher deposition of 222 Rn decay products on leafy vegetables.

  17. Tetra- and hexavalent uranium forms bidentate-mononuclear complexes with particulate organic matter in a naturally uranium-enriched peatland

    DEFF Research Database (Denmark)

    Mikutta, Christian; Langner, Peggy; Bargar, John R.

    2016-01-01

    Peatlands frequently serve as efficient biogeochemical traps for U. Mechanisms of U immobilization in these organic matter-dominated environments may encompass the precipitation of U-bearing mineral(oid)s and the complexation of U by a vast range of (in)organic surfaces. The objective of this work...... of bidentate-mononuclear U(IV/VI) complexes with carboxyl groups. We neither found evidence for U shells at ∼3.9 Å, indicative of mineral-associated U or multinuclear U(IV) species, nor for a substantial P/Fe coordination of U. Our data indicates that U(IV/VI) complexation by natural organic matter prevents...... the precipitation of U minerals as well as U complexation by Fe/Mn phases at our field site, and suggests that organically complexed U(IV) is formed via reduction of organic matter-bound U(VI)....

  18. Thermoluminescent behavior of polyminerals from irradiated natural species (peppermint, pepper and origanum)

    International Nuclear Information System (INIS)

    Cruz Z, E.; Calderon, T.; Pineda, S.; Guzman M, A.; Gastelum, S.; Barboza F, M.; Calderon, T.

    2003-01-01

    The thermoluminescent behaviour of polyminerals from natural species was obtained in order to identify irradiated samples. The polyminerals was separated from organic part in the samples using methanol-water mixed 40:60. The commercial samples was exposured from 1 to 40 kGy in Gammabeam 651PT facility irradiator at National University of Mexico (UNAM). The glow curves from polyminerals shows a good behaviour for each dose, and the TL emission decays was present for 180 days storage in a dark room at room temperature. The maximum TL signals was located in around 220 for the samples, it is closely to TL emission from quartz and feldspars. (Author)

  19. Reinforcement of natural rubber/high density polyethylene blends with electron beam irradiated liquid natural rubber-coated rice husk

    Energy Technology Data Exchange (ETDEWEB)

    Chong, E.L.; Ahmad, Ishak [Polymer Research Center (PORCE), School of Chemical Science and Food Technology, Universiti Kebangsaan Malaysia 4, 43600 UKM Bangi, Selangor Darul Ehsan (Malaysia); Dahlan, H.M. [Radiation Processing Technology Division, Malaysian Nuclear Agency (Nuclear Malaysia), Bangi, 43000 Kajang, Selangor Darul Ehsan (Malaysia); Abdullah, Ibrahim, E-mail: dia@ukm.m [Polymer Research Center (PORCE), School of Chemical Science and Food Technology, Universiti Kebangsaan Malaysia 4, 43600 UKM Bangi, Selangor Darul Ehsan (Malaysia)

    2010-08-15

    Coating of rice husk (RH) surface with liquid natural rubber (LNR) and exposure to electron beam irradiation in air were studied. FTIR analysis on the LNR-coated RH (RHR) exposed to electron beam (EB) showed a decrease in the double bonds and an increase in hydroxyl and hydrogen bonded carbonyl groups arising from the chemical interaction between the active groups on RH surface with LNR. The scanning electron micrograph showed that the LNR formed a coating on the RH particles which transformed to a fine and clear fibrous layer at 20 kGy irradiation. The LNR film appeared as patches at 50 kGy irradiation due to degradation of rubber. Composites of natural rubber (NR)/high density polyethylene (HDPE)/RHR showed an optimum at 20-30 kGy dosage with the maximum stress, tensile modulus and impact strength of 6.5, 79 and 13.2 kJ/m{sup 2}, respectively. The interfacial interaction between the modified RH and TPNR matrix had improved on exposure of RHR to e-beam at 20-30 kGy dosage.

  20. New Green Polymeric Composites Based on Hemp and Natural Rubber Processed by Electron Beam Irradiation

    Directory of Open Access Journals (Sweden)

    Maria-Daniela Stelescu

    2014-01-01

    Full Text Available A new polymeric composite based on natural rubber reinforced with hemp has been processed by electron beam irradiation and characterized by several methods. The mechanical characteristics: gel fraction, crosslink density, water uptake, swelling parameters, and FTIR of natural rubber/hemp fiber composites have been investigated as a function of the hemp content and absorbed dose. Physical and mechanical properties present a significant improvement as a result of adding hemp fibres in blends. Our experiments showed that the hemp fibers have a reinforcing effect on natural rubber similar to mineral fillers (chalk, carbon black, silica. The crosslinking rates of samples, measured using the Flory-Rehner equation, increase as a result of the amount of hemp in blends and the electron beam irradiation dose increasing. The swelling parameters of samples significantly depend on the amount of hemp in blends, because the latter have hydrophilic characteristics.

  1. Determination of the isotopic composition of natural and slightly enriched uranium by alpha-spectrometry

    DEFF Research Database (Denmark)

    Kunzendorf, Helmar

    1968-01-01

    Determinations of the isotope contents of 238U, 235U and 234U in five uranium samples containing 0–5 at% 235U were carried out on the basis of a least-squares fit of the α-spectra from the samples, measured with a semiconductor detector, to the theoretically expected α-spectra. With a simple source...

  2. Spectroscopic Evidence of Uranium Immobilization in Acidic Wetlands by Natural Organic Matter and Plant Roots

    Science.gov (United States)

    Biogeochemistry of uranium in wetlands plays important roles in U immobilization in storage ponds of U mining and processing facilities but has not been well understood. The objective of this work was to study molecular mechanisms responsible for high U retention by Savannah Ri...

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

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

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

  4. Uranium toxicology

    International Nuclear Information System (INIS)

    Ferreyra, Mariana D.; Suarez Mendez, Sebastian

    1997-01-01

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

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

    International Nuclear Information System (INIS)

    Phrommavanh, V.

    2008-10-01

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

  6. Contribution to the study of defects created by {alpha} particles in uranium at 4.2 K; Contribution a l'etude des defauts crees par irradiation a l'aide de particules {alpha} dans l'uranium a 4.2 K

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-07-01

    A device is described for the irradiation, in liquid helium, of metallic strips with {alpha} particles produced by radioactive sources. It has thereby been possible to measure changes in resistivity of variously treated uranium samples (cold- worked, annealed, previously exposed to neutrons, etc. ) as a function of the irradiation flux. The annealings carried out after irradiation compare favorably to those effected after a quenching from 100 to 4 K (JOUSSET experiments). The results are discussed; it is concluded that a defect, very probably of the interstitial type, is mobile in uranium at temperatures below 5 K. (author) [French] On decrit un dispositif permettant d'irradier, dans l'helium liquide, des lames metalliques par des particules {alpha} issues de sources radioactives. On a ainsi mesure les variations de resistivite, en fonction du flux d'irradiation, d'uranium diversement traite (ecroui, recuit, prealablement irradie par des neutrons...). Les recuits apres irradiation se comparent bien aux recuits apres trempe de 100 a 4 K (experiences de JOUSSET). L'ensemble des resultats est discute et il conduit a la conclusion qu'un defaut, tres vraisemblablement interstitiel, est mobile dans l'uranium a des temperatures inferieures a 5 K. (auteur)

  7. Contribution to the study of defects created by {alpha} particles in uranium at 4.2 K; Contribution a l'etude des defauts crees par irradiation a l'aide de particules {alpha} dans l'uranium a 4.2 K

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-07-01

    A device is described for the irradiation, in liquid helium, of metallic strips with {alpha} particles produced by radioactive sources. It has thereby been possible to measure changes in resistivity of variously treated uranium samples (cold- worked, annealed, previously exposed to neutrons, etc. ) as a function of the irradiation flux. The annealings carried out after irradiation compare favorably to those effected after a quenching from 100 to 4 K (JOUSSET experiments). The results are discussed; it is concluded that a defect, very probably of the interstitial type, is mobile in uranium at temperatures below 5 K. (author) [French] On decrit un dispositif permettant d'irradier, dans l'helium liquide, des lames metalliques par des particules {alpha} issues de sources radioactives. On a ainsi mesure les variations de resistivite, en fonction du flux d'irradiation, d'uranium diversement traite (ecroui, recuit, prealablement irradie par des neutrons...). Les recuits apres irradiation se comparent bien aux recuits apres trempe de 100 a 4 K (experiences de JOUSSET). L'ensemble des resultats est discute et il conduit a la conclusion qu'un defaut, tres vraisemblablement interstitiel, est mobile dans l'uranium a des temperatures inferieures a 5 K. (auteur)

  8. Chapter 8: Exponential experiments on graphite moderated lattices fuelled by natural uranium tubes containing cylindrical graphite cores

    International Nuclear Information System (INIS)

    McCulloch, D.B.; Hoskins, T.A.

    1963-01-01

    Experiments have been carried out using a fuel element comprising a 2.75 in. o.d./2.40 in. i.d. natural uranium tube containing a graphite core of diameter 2.0 in. Values of material buckling and migration area asymmetry for lattices at 7 in., 8 in. and 8/2 in. pitch have been obtained, and correlated with the theory of Syrett (1961) to derive an effective resonance integral for the cored element. By comparison with the resonance integral for the same fuel tube without a core, a value for the constant 'γ' of the theory of Stace (1959) is obtained. (author)

  9. Study in situ of the natural uranium, 60 Co and 137 Cs bioaccumulation factor in fish (Cyprinus carpio)

    International Nuclear Information System (INIS)

    Todoran, A.; Toma, A.; Dulama, C.; Horhoianu, V.; Hirica, O.; Patriche, N.; Tenciu, M.; Talpes, M.; Cristea, V.

    2006-01-01

    The paper presents the results of the 'in situ' research, aiming to determine the bioaccumulation factor of natural uranium, 60 Co and 137 Cs in fish (Cyprinus carpio) - the find link in aquatic ecosystems. The work performed is a part of a radioecological study achieved in the experimental pool of S.C.N. Pitesti. The objective of the research was to evaluate the release of the radioactive materials in the environment as well as to establish the transfer mechanisms of the radionuclides in the trophic chains from the aquatic ecosystem. (authors)

  10. Study in situ of the natural uranium, 60 Co and 137 Cs bioaccumulation factor in fish (Cyprinus carpio)

    Energy Technology Data Exchange (ETDEWEB)

    Todoran, A.; Toma, A.; Dulama, C.; Horhoianu, V.; Hirica, O. [Institute for Nuclear Research, Pitesti (Romania); Patriche, N.; Tenciu, M.; Talpes, M. [CPPPPIP, Galati (Romania); Cristea, V. [Galati Univ. (Romania)

    2006-07-01

    The paper presents the results of the 'in situ' research, aiming to determine the bioaccumulation factor of natural uranium, {sup 60}Co and {sup 137}Cs in fish (Cyprinus carpio) - the find link in aquatic ecosystems. The work performed is a part of a radioecological study achieved in the experimental pool of S.C.N. Pitesti. The objective of the research was to evaluate the release of the radioactive materials in the environment as well as to establish the transfer mechanisms of the radionuclides in the trophic chains from the aquatic ecosystem. (authors)

  11. Uranium determination in natural U O2 samples for the laboratory intercomparison program of Agencia Brasileiro-Argentina de Contabilidade e Controle de Materiais Nucleares (ABACC)

    International Nuclear Information System (INIS)

    Avelar, Marta M.; Palmieri, Helena E.L.; Reis Fagundes, Oliene dos

    1997-01-01

    The modified Davies and Gray method for uranium titration to analyse nuclear materials is the procedure used by the CDTN's chemical laboratory. Its analytical performance was evaluated through the participation in the intercomparison program with the Brazilian - Argentine Agency for Accountability and Control of Nuclear Materials (ABACC). One sample of natural uranium dioxide was analysed. The precision and accuracy of the measurements are reported and discussed in this paper. (author). 7 refs., 1 fig., 2 tabs

  12. Extractable proteins from electron beam (EB) irradiated natural rubber (NR) latex

    International Nuclear Information System (INIS)

    Feroza Akhtar; Fumio Yoshii; Keizo Makuuchi

    1996-01-01

    The protein assay of natural rubber latex (NRL) vulcanized by low energy electron beam (EB, 300 keV, 30 mA) has been carried out using Bicinchoninic acid (BCA) reagent. Extractable protein in irradiated latex film was determined by measuring the absorption of colored solution at 562 nm using UV spectrometer. The effect of various radiation doses on the extractable protein content of NRL was investigated. It was ,found that the quantities of extractable protein increases with radiation dose. When compared with ,gamma-ray irradiated samples the same trend was observed. Electron beam irradiated latex films are leached in 1% (ammonia water for various lengths of time. From the results it was established that within 2 hours of leaching in ammonia water most of the extractable protein (96%) were removed from rubber film

  13. On some paramagnetic species induced in natural calcites by β and γ-rays irradiations

    International Nuclear Information System (INIS)

    Rossi, A.; Danon, J.

    1985-01-01

    The ESR absorption lines of calcite speleothems are studied both as monocrystals and powders, after energetic β-rays or γ-rays irradiation. Both Kinds of irradiation produce same lines. Angular variation studies of monocrystals revealed four induced paramagnetic species stable at room temperature. Three of these were attributed to CO 3 sup(---) group, CO 2 sup(-) groups with axial and orthorhombic symetry and a fourth one could be due to the CO 3 sup(-) group. Powder spectra show that these lines, are activated by irradiation in all speleothems we studied and can be present either in natural ESR spectra. Their relationships to the lines usually considered for ESR dating are discussed. (Author) [pt

  14. Radiation vulcanization of natural rubber latex using irradiation n-butyl acrylate aqueous emulsion as sensitizer

    International Nuclear Information System (INIS)

    Vo Van Thien; Nguyen Quoc Hien; Keizo Makuuchi; Fumio Yoshii

    2000-01-01

    Natural rubber latex was vulcanized by gamma radiation with n-butyl acrylate aqueous emulsion irradiated at dose of 1.5 kGy as sensitizer. The total solid content of latex increases on the irradiation dose. The viscosity of latex on the standing time was investigated and became stable after one month of storage. The gel content of latex films increasing with irradiation dose and attained more than 94% at dose of 10 kGy. Tensile strength of films reached the values of 31MPa; 30 Mpa and 25 Mpa at vulcanization doses of 20 kGy, 15 kGy and 8 kGy for the concentrations of sensitizer 7 phr, 9 phr and 13 phr respectively. Elongation at break decreases as increasing dose. Tear strength of rubber films was from 30-40 N/mm. The tackiness of latex films decreases and smell of vulcanized latex is almost negligible. (author)

  15. Effects of electron beam irradiated natural casings on the quality properties and shelf stability of emulsion sausage

    Science.gov (United States)

    Kim, Hyun-Wook; Choi, Ji-Hun; Choi, Yun-Sang; Kim, Hack-Youn; Hwang, Ko-Eun; Song, Dong-Heon; Lee, Ju-Woon; Kim, Cheon-Jei

    2012-05-01

    The effect of electron beam irradiated hog and sheep casings (1, 3, and 8 kGy) on the physicochemical properties and shelf stability of emulsion sausage was evaluated. There were no significant differences in pH, instrumental color, sensory properties (overall acceptability), and hardness between all the samples. The cooking yields for the irradiated treated samples were larger than that of the yields obtained for the non-irradiated samples for both the hog and sheep casing. The irradiated natural casings accelerated lipid oxidation, and inhibited the formation of volatile basic nitrogen and the increase in total aerobic bacteria. In conclusion, the natural casings irradiated below at a dose of 3 kGy had no effect on physicochemical and sensory properties of the emulsion sausages, however, that improved the shelf-stability over 5 weeks. Therefore, natural casings irradiated at moderate doses are suitable for sausage production.

  16. Uranium, depleted uranium, biological effects

    International Nuclear Information System (INIS)

    2001-01-01

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

  17. Effects of electron beam irradiated natural casings on the quality properties and shelf stability of emulsion sausage

    International Nuclear Information System (INIS)

    Kim, Hyun-Wook; Choi, Ji-Hun; Choi, Yun-Sang; Kim, Hack-Youn; Hwang, Ko-Eun; Song, Dong-Heon; Lee, Ju-Woon; Kim, Cheon-Jei

    2012-01-01

    The effect of electron beam irradiated hog and sheep casings (1, 3, and 8 kGy) on the physicochemical properties and shelf stability of emulsion sausage was evaluated. There were no significant differences in pH, instrumental color, sensory properties (overall acceptability), and hardness between all the samples. The cooking yields for the irradiated treated samples were larger than that of the yields obtained for the non-irradiated samples for both the hog and sheep casing. The irradiated natural casings accelerated lipid oxidation, and inhibited the formation of volatile basic nitrogen and the increase in total aerobic bacteria. In conclusion, the natural casings irradiated below at a dose of 3 kGy had no effect on physicochemical and sensory properties of the emulsion sausages, however, that improved the shelf-stability over 5 weeks. Therefore, natural casings irradiated at moderate doses are suitable for sausage production. - Highlights: ► The effect of E-beam irradiated natural casings on sausage quality was evaluated. ► The use of irradiated casings improved shelf stability of sausage. ► Natural casings irradiated below 3 kGy are suitable for sausage production.

  18. Identification of Uranium Minerals in Natural U-Bearing Rocks Using Infrared Reflectance Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Beiswenger, Toya N. [Pacific Northwest National Laboratory, Richland, WA, USA; Gallagher, Neal B. [Eigenvector Research, Inc., Manson, WA, USA; Myers, Tanya L. [Pacific Northwest National Laboratory, Richland, WA, USA; Szecsody, James E. [Pacific Northwest National Laboratory, Richland, WA, USA; Tonkyn, Russell G. [Pacific Northwest National Laboratory, Richland, WA, USA; Su, Yin-Fong [Pacific Northwest National Laboratory, Richland, WA, USA; Sweet, Lucas E. [Pacific Northwest National Laboratory, Richland, WA, USA; Lewallen, Tricia A. [Pacific Northwest National Laboratory, Richland, WA, USA; Johnson, Timothy J. [Pacific Northwest National Laboratory, Richland, WA, USA

    2017-10-24

    The identification of minerals, including uranium-bearing minerals, is traditionally a labor-intensive-process using x-ray diffraction (XRD), fluorescence, or other solid-phase and wet chemical techniques. While handheld XRD and fluorescence instruments can aid in field identification, handheld infrared reflectance spectrometers can also be used in industrial or field environments, with rapid, non-destructive identification possible via spectral analysis of the solid’s reflectance spectrum. We have recently developed standard laboratory measurement methods for the infrared (IR) reflectance of solids and have investigated using these techniques for the identification of uranium-bearing minerals, using XRD methods for ground-truth. Due to the rich colors of such species, including distinctive spectroscopic signatures in the infrared, identification is facile and specific, both for samples that are pure or are partially composed of uranium (e.g. boltwoodite, schoepite, tyuyamunite, carnotite, etc.) or non-uranium minerals. The method can be used to detect not only pure and partial minerals, but is quite sensitive to chemical change such as hydration (e.g. schoepite). We have further applied statistical methods, in particular classical least squares (CLS) and multivariate curve resolution (MCR) for discrimination of such uranium minerals and two uranium pure chemicals (U3O8 and UO2) against common background materials (e.g. silica sand, asphalt, calcite, K-feldspar) with good success. Each mineral contains unique infrared spectral features; some of the IR features are similar or common to entire classes of minerals, typically arising from similar chemical moieties or functional groups in the minerals: phosphates, sulfates, carbonates, etc. These characteristic 2 infrared bands generate the unique (or class-specific) bands that distinguish the mineral from the interferents or backgrounds. We have observed several cases where the chemical moieties that provide the

  19. Overview of the technological enhancement of natural radiation in the Brazilian non-uranium mining industry

    International Nuclear Information System (INIS)

    Fernandes, H.M.; Pires do Rio, M.A.; Rosa, R.; Veiga, L.H.S.; Amaral, E.C.S.

    2002-01-01

    The mining and milling of ores with significant amounts of uranium and thorium associated to the main ore has the potential to pose undue health risks to members of the general public and workers. In order to assess the status of this problem in the Brazilian non-uranium mining industries a comprehensive investigation project has been undertaken. The adopted methodology was based on the detailed analysis of each investigated industry operational flowplan, mass balance calculations, risk assessment (operational and post-operational scenarios taken into account) and environmental management principles. This papers addresses the main issues arising from the investigation effort, reports the most relevant conclusions and states the future studies to be implemented. It could be observed that these industries have the potential to cause relevant radiological impacts and must be regulated/controlled as to avoid these problems. (author)

  20. An assessment of the long term interaction of uranium tailings with the natural environment

    International Nuclear Information System (INIS)

    Lush, D.; Fletcher, R.; Goode, J.; Jurgens, T.

    1978-01-01

    Current investigations of methods for the management of tailings at uranium mill sites raise pertinent questions as to accuracy of our identification of potential hazards and their causes. Of particular relevance are the physical-chemical geomechanisms which may lead to the dispersion of contaminants into the environment and eventually into the food chain. This paper looks at present practices of uranium mill tailings storage in the light of 'Perpetual Care' management concepts and requirements. It examines the potential geomechanisms of transport that would be acting on the tailing over the next millenia. Interesting parallels are drawn between these mechanisms and those geomechanisms which led to the formation of many of the original ore deposits. Central to the substance of this paper is a study currently being undertaken for the Atomic Energy Control Board of Canada. Selected elements to this study will be presented in the paper together with a discussion of relevant peripheral issues

  1. The role of naturally occurring biofilm in the treatment of mine water in abandoned uranium mine

    International Nuclear Information System (INIS)

    Mielnicki, S.; Sklodowska, A.; Michalska, B.

    2014-01-01

    The uranium mine in Kowary (SW Poland) was active from 1948 to 1967. After exploitation ceased the mine was abandoned and from the beginning of 21"s"t century it is a touristic attraction of this region of Poland. The largest uranium mining fields, Kowary and Kowary-Podgorze, were located in southern part of the metamorphic cover of the Karkonosze Granite. In the mine dumps at Kowary- Podgorze ore fragments containing up to 0.15% of uranium can still be found. Several dumps have been left in the Kowary Podgorze vicinity as the post mining uranium waste. The dump of adits Nos. 19 and 19a at Kowary Podgorze is located in the Jedlica River valley. Water from adit No. 19a is still discharged by the pipe directly to the Jedlica River. In the end of this pipe a small dam was built to regulate the level of water in adit and small reservoir of mine water was created in this place. The level of uranium observed in water before dam is between 10 μg/dm"3 and 670 μg/dm"3. The bottom of reservoir is covered by strongly mineralized biofilm containing up to 60 mg U/kg (dry weight), 1 500 mg As/kg, 10 000 mg Al/kg and about 1700 mg Mn/kg. Water in Jedlica River contains 6- 7 μg U/dm"3, 16 μg As/dm"3 and about 10 μg Mn/dm"3 and these values are within the limits for non contaminated surface water. The water from the reservoir together with the biofilm is discharged minimum twice a year immediately to Jedlica River causing a temporary increase of contaminants (beyond the limits) and dispersion of uranium and arsenic up to 20 km from the main source of pollution. It seems that biofilm from reservoir acts as an active filter that removes main contaminants from mine water mainly through biosorption. Laboratory studies show that sorption complexes are relatively stable. Maximum 10% of absorbed uranium was eluted by EDTA buffer or acetic acid (soluble and carbonate fraction). Arsenic was eluted in 25% by phosphate buffer (ion exchange) and almost all iron and cadmium (occurring in

  2. Natural arsenic and uranium accumulation and remobilization in different geological environments

    Energy Technology Data Exchange (ETDEWEB)

    Banning, Andre Wilhelm

    2012-03-05

    Despite the fact that both As and U represent geogenic trace elements potentially toxic to humans, little information is available on the development of their enrichments in German sediments and their potential impact on groundwater quality, let alone a systematic overview of the country's natural occurrences. This work aims at characterizing accumulation processes in aquifers actually or potentially affected by elevated concentrations of As and/or U, and their timings in geological history. The five selected study areas provide different geological and stratigraphical backgrounds. Identification of As and U sources, and structural derivation of their environmental reservoirs as well as remobilization mechanisms potentially resulting in trace element release to groundwater were assessed. Drinking water supply in Franconia/Northern Bavaria is dependent on groundwater extraction from terrestrial Upper Triassic sandstones where elevated concentrations of geogenic U and As exceeding German drinking water limitations were identified. Characterization of aquifer material in terms of geochemical and mineralogical composition, trace elements distribution on a microscale and their mineralogical fractionation and mobilization behaviour showed that uraniferous francolite/hematite inclusions within the aquifer sandstones (''active arkoses'') represent important sources for U and As in the study area. Francolite exhibits biologically, structurally and radiation-enhanced solubility; loss of both U and As during weathering was documented. Jurassic shallow marine Fe ores from the Upper Rhine Graben exhibit significant bulk As hosted in mainly goethite ooids slowly formed in times of condensed sedimentation. The study indicates that As accumulation was favoured over other potential contaminants, esp. heavy metals. Conditions for As accumulation varied during deposition, visible on a macro- (outcrop) as well as on a microscale (single Fe ooid). However, the

  3. Natural arsenic and uranium accumulation and remobilization in different geological environments

    Energy Technology Data Exchange (ETDEWEB)

    Banning, Andre Wilhelm

    2012-03-05

    Despite the fact that both As and U represent geogenic trace elements potentially toxic to humans, little information is available on the development of their enrichments in German sediments and their potential impact on groundwater quality, let alone a systematic overview of the country's natural occurrences. This work aims at characterizing accumulation processes in aquifers actually or potentially affected by elevated concentrations of As and/or U, and their timings in geological history. The five selected study areas provide different geological and stratigraphical backgrounds. Identification of As and U sources, and structural derivation of their environmental reservoirs as well as remobilization mechanisms potentially resulting in trace element release to groundwater were assessed. Drinking water supply in Franconia/Northern Bavaria is dependent on groundwater extraction from terrestrial Upper Triassic sandstones where elevated concentrations of geogenic U and As exceeding German drinking water limitations were identified. Characterization of aquifer material in terms of geochemical and mineralogical composition, trace elements distribution on a microscale and their mineralogical fractionation and mobilization behaviour showed that uraniferous francolite/hematite inclusions within the aquifer sandstones (''active arkoses'') represent important sources for U and As in the study area. Francolite exhibits biologically, structurally and radiation-enhanced solubility; loss of both U and As during weathering was documented. Jurassic shallow marine Fe ores from the Upper Rhine Graben exhibit significant bulk As hosted in mainly goethite ooids slowly formed in times of condensed sedimentation. The study indicates that As accumulation was favoured over other potential contaminants, esp. heavy metals. Conditions for As accumulation varied during deposition, visible on a macro- (outcrop) as well as on a microscale (single Fe ooid). However, the risk of As release to

  4. Natural arsenic and uranium accumulation and remobilization in different geological environments

    International Nuclear Information System (INIS)

    Banning, Andre Wilhelm

    2012-01-01

    Despite the fact that both As and U represent geogenic trace elements potentially toxic to humans, little information is available on the development of their enrichments in German sediments and their potential impact on groundwater quality, let alone a systematic overview of the country's natural occurrences. This work aims at characterizing accumulation processes in aquifers actually or potentially affected by elevated concentrations of As and/or U, and their timings in geological history. The five selected study areas provide different geological and stratigraphical backgrounds. Identification of As and U sources, and structural derivation of their environmental reservoirs as well as remobilization mechanisms potentially resulting in trace element release to groundwater were assessed. Drinking water supply in Franconia/Northern Bavaria is dependent on groundwater extraction from terrestrial Upper Triassic sandstones where elevated concentrations of geogenic U and As exceeding German drinking water limitations were identified. Characterization of aquifer material in terms of geochemical and mineralogical composition, trace elements distribution on a microscale and their mineralogical fractionation and mobilization behaviour showed that uraniferous francolite/hematite inclusions within the aquifer sandstones (''active arkoses'') represent important sources for U and As in the study area. Francolite exhibits biologically, structurally and radiation-enhanced solubility; loss of both U and As during weathering was documented. Jurassic shallow marine Fe ores from the Upper Rhine Graben exhibit significant bulk As hosted in mainly goethite ooids slowly formed in times of condensed sedimentation. The study indicates that As accumulation was favoured over other potential contaminants, esp. heavy metals. Conditions for As accumulation varied during deposition, visible on a macro- (outcrop) as well as on a microscale (single Fe ooid). However, the

  5. Medium and long-term supply of the FRG with natural uranium

    Energy Technology Data Exchange (ETDEWEB)

    Stephany, M

    1976-08-01

    A short survey is presented of the situation concerning the FRG's uranium supply taking into special consideration the economical aspects. Characteristic for the demand-supply-situation is the fact that the development of prices does not influence the costs as much as this is the case with other fuels, and that assurance of supply for the FRG is underpinned by participation in foreign enterprises.

  6. Natural γ radioactivity and its modifications by uranium mining in southern Brittany and Vendee, France

    International Nuclear Information System (INIS)

    Barbaroux, L.

    1985-01-01

    Uranium mining has increased the gamma radioactivity by up to 80 times in some areas. The activity also varies, by a factor of 5, with rock composition. The most important problems arise from the dispersion of unshielded radioactive material and the lack of rehabilitation of old mining areas. The continued existence of these problems reveals the inadequacy of existing laws, the past absence of social responsibility and a serious gap in the measures for the protection of public health. (author)

  7. NSRR experiment with un-irradiated uranium-zirconium hydride fuel. Design, fabrication process and inspection data of test fuel rod

    Energy Technology Data Exchange (ETDEWEB)

    Sasajima, Hideo; Fuketa, Toyoshi; Ishijima, Kiyomi; Kuroha, Hiroshi; Ikeda, Yoshikazu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Aizawa, Keiichi

    1998-08-01

    An experiment plan is progressing in the Nuclear Safety Research Reactor (NSRR) to perform pulse-irradiation with uranium-zirconium hydride (U-ZrH{sub x}) fuel. This fuel is widely used in the training research and isotope production reactor of GA (TRIGA). The objectives of the experiment are to determine the fuel rod failure threshold and to investigate fuel behavior under simulated reactivity initiated accident (RIA) conditions. This report summarizes design, fabrication process and inspection data of the test fuel rods before pulse-irradiation. The experiment with U-ZrH{sub x} fuel will realize precise safety evaluation, and improve the TRIGA reactor performance. The data to be obtained in this program will also contribute development of next-generation TRIGA reactor and its safety evaluation. (author)

  8. On nature of spontaneous elongation of polymers preliminarily stretched in adsorption-active media under irradiation

    International Nuclear Information System (INIS)

    Sinevich, E.A.; Prazdnichnyj, A.M.; Tikhomirov, V.S.; Bakeev, N.F.

    1989-01-01

    The nature of the spontaneous elongation under irradiation with fast electrons of polymers preliminary stretched in adsorption-active media has been studied. This effect is related with radiation-induced heating of microporous polymer samples. Its manifestation in amorphous PETP requires the presence of crazes having well developed microfibrillar structure. The spontaneous elongation effect is shown to be a result of crystallization of partially oriented material in transitional regions relating the oriented material of microfibrils inside crazes with nonstrained polymer between them

  9. Evaluation of plutonium, uranium, and thorium use in power reactor fuel cycles

    International Nuclear Information System (INIS)

    Kasten, P.R.; Homan, F.J.

    1977-01-01

    The increased cost of uranium and separative work has increased the attractiveness of plutonium use in both uranium and thorium fuel cycles in thermal reactors. A technology, fuel utilization, and economic evaluation is given for uranium and thorium fuel cycles in various reactor types, along with the use of plutonium and 238 U. Reactors considered are LWRs, HWRs, LWBRs, HTGRs, and FBRs. Key technology factors are fuel irradiation performance and associated physical property values. Key economic factors are unit costs for fuel fabrication and reprocessing, and for refabrication of recycle fuels; consistent cost estimates are utilized. In thermal reactors, the irradiation performance of ceramic fuels appears to be satisfactory. At present costs for uranium ore and separative work, recycle of plutonium with thorium rather than uranium is preferable from fuel utilization and economic viewpoints. Further, the unit recovery cost of plutonium is lower from LWR fuels than from natural-uranium HWR fuels; use of LWR product permits plutonium/thorium fueling to compete with uranium cycles. Converting uranium cycles to thorium cycles increases the energy which can be extracted from a given uranium resource. Thus, additional fuel utilization improvement can be obtained by fueling all thermal reactors with thorium, but this requires use of highly enriched uranium; use of 235 U with thorium is most economic in HTGRs followed by HWRs and then LWRs. Marked improvement in long-term fuel utilization can be obtained through high thorium loadings and short fuel cycle irradiations as in the LWBR, but this imposes significant economic penalties. Similar operating modes are possible in HWRs and HTGRs. In fast reactors, use of the plutonium-uranium cycle gives advantageous fuel resource utilization in both LMFBRs and GCFRs; use of the thorium cycle provides more negative core reactivity coefficients and more flexibility relative to use of recycle fuels containing uranium of less than 20

  10. Distribution of natural radionuclides and uranium activity ratio in Gulf of Thailand sediments as base line data

    Energy Technology Data Exchange (ETDEWEB)

    Sahoo, S.K.; Hideki, A. [National Institute of Radiological Sciences (Japan); Kritsananuwat, R.; Fukushi, M. [Tokyo Metropolitan University (Japan); Chanyotha, S.; Pangza, K. [Chulalongkorn University (Thailand)

    2014-07-01

    This paper reports distribution of naturally occurring radionuclides and uranium activity ratio in marine sediments from selected coast, along the Gulf of Thailand to establish baseline data. Thailand has a plan to construct nuclear power plants (NPPs) as well as coal-fired thermal power plants to generate adequate and reliable electricity supply for rapid growth of industrialization. Therefore, it is important to focus not only on security and adequacy of power system but also on environmental protection and monitoring and risk assessment. To carry out environmental monitoring, baseline data plays a significant role. These data should be established and available before set up of mega projects that could impact the environment and health. Therefore, we have collected samples from five areas in the Gulf of Thailand, which are proposed as potential sites, to set up power plants by Thailand government. A total number of fifty-four marine sediment samples were collected. Gamma spectroscopy was used to determine the concentration of natural radionuclides e.g. {sup 226}Ra, {sup 228}Ac and {sup 40}K. Activity concentrations of {sup 226}Ra, {sup 228}Ac and {sup 40}K vary from 2.91-67.17 Bq/kg with an average of 26.64±14.57 Bq/kg, 4.42-109.17 Bq/kg with an average of 43.79±23.92 Bq/kg and 3.36-1004.56 Bq/kg with an average of 393.56±208.04 Bq/kg, respectively. The radiation hazard parameters including absorbed dose rate (D), annual effective dose equivalent (AEDE), radium equivalent activity (AGDE) and external hazard index (Hex) were calculated and compared with the international recommended values. We have noticed that sediments from two sites characterized by similar geological nature of landforms with a rocky coast have higher concentration of natural radionuclides. Concentration of uranium was determined using the inductively coupled plasma mass spectrometry (ICP-MS) and isotopic composition of {sup 234}U/{sup 238}U and {sup 235}U/{sup 238}U were determined using

  11. Graft Copolymerization of Methyl Methacrylate Monomer onto Starch and Natural Rubber Latex Initiated by Gamma Irradiation

    Directory of Open Access Journals (Sweden)

    S. Iskandar

    2011-04-01

    Full Text Available To obtain the degradable plastic, the graft copolymerization of methyl methacrylate onto starch and natural rubber latex was conducted by a simultaneous irradiation technique. Gamma-ray from cobalt-60 source was used as the initiator. The grafted copolymer of starch-polymethyl methacrylate and the grafted copolymer of natural rubber-polymethyl methacrylate were mixed in the blender, and dried it in the oven. The dried grafted copolymer mixture was then molded using hydraulic press machine. The effect of irradiation dose, composition of the grafted copolymer mixture, film forming condition and recycle effect was evaluated. The parameters observed were tensile strength, gel fraction and soil burial degradability of grafted copolymer mixture. It was found that the tensile strength of grafted copolymer mixture increased by -ray irradiation. Increasing of the grafted copolymer of natural rubber-polymethyl methacrylate content, the gel fraction and tensile strength of the grafted copolymer mixture increased. The tensile strength of the grafted copolymer mixture was increased from 18 MPa to 23 MPa after recycled (film forming reprocessed 3 times. The grafted copolymer mixture was degraded completely after soil buried for 6 months

  12. Biochemical and hematological study of goats envenomed with natural and 60Co-irradiated bothropic venom

    International Nuclear Information System (INIS)

    Lucas de Oliveira, P.C.; Madruga, R.A.; Barbosa, N.P.U.; Sakate, M.

    2007-01-01

    Venoms from snakes of the Bothrops genus are proteolytic, coagulant, hemorrhagic and nephrotoxic, causing edema, necrosis, hemorrhage and intense pain at the bite site, besides systemic alterations. Many adjuvants have been added to the venom used in the sensitization of antiserum-producer animals to increase antigenic induction and reduce the envenomation pathological effects. Gamma radiation from 60 Co has been used as an attenuating agent of the venoms toxic properties. The main objective was to study, comparatively, clinical and laboratory aspects of goats inoculated with bothropic (Bothrops jararaca) venom, natural and irradiated from a 60 Co source. Twelve goats were divided into two groups of six animals: GINV, inoculated with 0.5 mg/kg of natural venom; and GIIV, inoculated with 0.5 mg/kg of irradiated venom. Blood samples were collected immediately before and one, two, seven, and thirty days after venom injection. Local lesions were daily evaluated. The following exams were carried out: blood tests; biochemical tests of urea, creatinine, creatine kinase, aspartate amino-transferase and alanine amino-transferase; clotting time; platelets count; and total serum immunoglobulin measurement. In the conditions of the present experiment, irradiated venom was less aggressive and more immunogenic than natural venom. (author)

  13. Biochemical and hematological study of goats envenomed with natural and 60Co-irradiated bothropic venom

    Energy Technology Data Exchange (ETDEWEB)

    Lucas de Oliveira, P.C.; Madruga, R.A.; Barbosa, N.P.U. [Uberaba School of Veterinary Medicine (UNIUBE), MG (Brazil)]. E-mail: pedrolucaso@uol.com.br; Sakate, M. [UNESP, Botucatu, SP (Brazil). School of Veterinary Medicine and Animal Husbandry

    2007-07-01

    Venoms from snakes of the Bothrops genus are proteolytic, coagulant, hemorrhagic and nephrotoxic, causing edema, necrosis, hemorrhage and intense pain at the bite site, besides systemic alterations. Many adjuvants have been added to the venom used in the sensitization of antiserum-producer animals to increase antigenic induction and reduce the envenomation pathological effects. Gamma radiation from {sup 60}Co has been used as an attenuating agent of the venoms toxic properties. The main objective was to study, comparatively, clinical and laboratory aspects of goats inoculated with bothropic (Bothrops jararaca) venom, natural and irradiated from a {sup 60}Co source. Twelve goats were divided into two groups of six animals: GINV, inoculated with 0.5 mg/kg of natural venom; and GIIV, inoculated with 0.5 mg/kg of irradiated venom. Blood samples were collected immediately before and one, two, seven, and thirty days after venom injection. Local lesions were daily evaluated. The following exams were carried out: blood tests; biochemical tests of urea, creatinine, creatine kinase, aspartate amino-transferase and alanine amino-transferase; clotting time; platelets count; and total serum immunoglobulin measurement. In the conditions of the present experiment, irradiated venom was less aggressive and more immunogenic than natural venom. (author)

  14. The location of uranium in source rocks and sites of secondary deposition at the Needle's Eye natural analogue site, Dumfries and Galloway

    International Nuclear Information System (INIS)

    Basham, I.R.; Hyslop, E.K.; Milodowski, A.E.; Pearce, J.M.

    1989-08-01

    The British Geological Survey has been conducting a co-ordinated research programme at the natural analogue site of Needle's Eye at Southwick on the Solway coast in SW Scotland. This study of a naturally radioactive geochemical system has been carried out with the aim of improving our confidence in using predictive models of radionuclide migration in the geosphere. This report describes results of integrated mineralogical techniques which have been applied to the study of both the 'source-term' and sites of secondary accumulation of uranium. Pitchblende in a polymetallic-carbonate breccia vein exposed in ancient sea-cliffs is the main source of labile uranium although other uranium-bearing minerals present in the granodiorite and hornfelsed siltstone host-rocks present probable ancillary leachable sites. In keeping with the complex chemistry of the primary sulphide-rich mineralization, a large variety of secondary U minerals has been recorded among which arsenates and hydrous silicates appear to predominate. Uranium transported in groundwaters draining the cliffs has accumulated in organic-rich estuarine/intertidal mudflat sediments of Quaternary age. Charged particle track registration techniques have demonstrated convincingly the effectiveness of humidified organic matter in retarding uranium transport and, coupled with scanning electron microscopy, have indicated an important role of living plants and bacteria in uranium uptake and concentration. (author)

  15. The location of uranium in source rocks and sites of secondary deposition at the Needle's Eye natural analogue site, Dumfries and Galloway

    International Nuclear Information System (INIS)

    Basham, I.R.; Hyslop, E.K.; Milodowski, A.E.; Pearce, J.M.

    1991-01-01

    The British Geological Survey has been conducting a coordinated research programme at the natural analogue site of Needle's Eye at Southwick on the Solway coast in south-west Scotland. This study of a naturally radioactive geochemical system has been carried out with the aim of improving our confidence in using predictive models of radionuclide migration in the geosphere. This report describes results of integrated mineralogical techniques which have been applied to the study of both the source-term and sites of secondary accumulation of uranium. Pitchblende in a polymetallic-carbonate breccia vein exposed in ancient sea-cliffs is the main source of labile uranium although other uranium-bearing minerals present in the granodiorite and hornfelsed siltstone host-rocks present probable ancillary leachable sites. In keeping with the complex chemistry of the primary sulphide-rich mineralization, a large variety of secondary U minerals has been recorded among which arsenates and hydrous silicates appear to predominate. Uranium transported in groundwaters draining the cliffs has accumulated in organic-rich estuarine/intertidal mudflat sediments of Quaternary age. Charged particle track registration techniques have demonstrated convincingly the effectiveness of humified organic matter in retarding uranium transport and, coupled with scanning electron microscopy, have indicated the important role of living plants and bacteria in uranium uptake and concentration. Computer codes used: CHEMVAL; CHEMTARD 5 figs.; 64 plates; 37 refs

  16. Effect of natural uranium on the UMR-106 osteoblastic cell line: impairment of the autophagic process as an underlying mechanism of uranium toxicity.

    Science.gov (United States)

    Pierrefite-Carle, Valérie; Santucci-Darmanin, Sabine; Breuil, Véronique; Gritsaenko, Tatiana; Vidaud, Claude; Creff, Gaelle; Solari, Pier Lorenzo; Pagnotta, Sophie; Al-Sahlanee, Rasha; Auwer, Christophe Den; Carle, Georges F

    2017-04-01

    Natural uranium (U), which is present in our environment, exerts a chemical toxicity, particularly in bone where it accumulates. Generally, U is found at oxidation state +VI in its oxocationic form [Formula: see text] in aqueous media. Although U(VI) has been reported to induce cell death in osteoblasts, the cells in charge of bone formation, the molecular mechanism for U(VI) effects in these cells remains poorly understood. The objective of our study was to explore U(VI) effect at doses ranging from 5 to 600 µM, on mineralization and autophagy induction in the UMR-106 model osteoblastic cell line and to determine U(VI) speciation after cellular uptake. Our results indicate that U(VI) affects mineralization function, even at subtoxic concentrations (metal exposure. We observed that U(VI) was able to rapidly activate autophagy but an inhibition of the autophagic flux was observed after 24 h. Thus, our results indicate that U(VI) perturbs osteoblastic functions by reducing mineralization capacity. Our study identifies for the first time U(VI) in the form of meta-autunite in mammalian cells. In addition, U(VI)-mediated inhibition of the autophagic flux may be one of the underlying mechanisms leading to the decreased mineralization and the toxicity observed in osteoblasts.

  17. Determination of uranium in natural waters and high-purity aluminum by flow-injection on-line preconcentration and ICP-MS detection

    International Nuclear Information System (INIS)

    Seki, Tatsuya; Oguma, Koichi

    2004-01-01

    A flow injection method has been developed for the determination of uranium is natural waters and high-purity aluminum by use of on-line preconcentration on a U/TEVA TM column and ICP-MS detection. The sample solution prepared as a nitric acid solution in 3 mol l -1 was passed through the U/TEVA TM column to collect uranium and uranium adsorbed was eluted with 0.1 mol l -1 nitric acid. The effluent was introduced directly into the nebulizer of the ICP-MS and 238 U was measured. The detection limit, calculated as 3-times the standard deviation of the background noise, was 3pg and the sample throughput was about 10 per hour. The proposed method was successfully applied to the determination of uranium in river-water reference materials, a seawater reference material and high-purity aluminum reference materials. (author)

  18. Natural pregnancy and normal delivery after intracapsular irradiation for symptomatic craniopharyngioma

    International Nuclear Information System (INIS)

    Kodama, Takafumi; Matsukado, Yasuhiko; Miura, Masaki; Takada, Akira

    1986-01-01

    Treatment for craniopharyngioma, particularly in adults and cases of recurrence, is still fraught with problems. One difficulty is that postoperative hormonal function may be abnormal even after successful surgery. We have treated craniopharyngioma primarily with simple evacuation and intracapsular irradiation, using 198 Au-colloid. Only a few cases of natural pregnancy and normal delivery following treatment for craniopharyngioma with hypothalamic extension have been reported. We will describe and discuss a case in which natural pregnancy and normal delivery occurred twice after such treatment. (author)

  19. Gamma irradiator design concepts for radiation vulcanisation of natural rubber latex

    International Nuclear Information System (INIS)

    Aggarwal, K.S.; Muralidharan, P.; Apte, M.G.; Kalurkar, A.R.; Shah, B.M.

    1990-01-01

    Radiation vulcanisation of natural rubber latex (NRL) is a new and yet unproven technology and one which involves undefined problems of consumer acceptance and high degree of radiation risk. Therefore, the designer should take care that the initial capital cost of the plant is as low as possible to keep the unit processing cost low during the initial lean period of the product requirement by the market. Three irradiators to process natural rubber latex have been designed as per capacity requirement of the user. Their salient features are described. (author). 2 tabs., 24 figs

  20. Natural pregnancy and normal delivery after intracapsular irradiation for symptomatic craniopharyngioma. Case report

    Energy Technology Data Exchange (ETDEWEB)

    Kodama, Takafumi; Matsukado, Yasuhiko; Miura, Masaki; Takada, Akira

    1986-01-01

    Treatment for craniopharyngioma, particularly in adults and cases of recurrence, is still fraught with problems. One difficulty is that postoperative hormonal function may be abnormal even after successful surgery. We have treated craniopharyngioma primarily with simple evacuation and intracapsular irradiation, using /sup 198/Au-colloid. Only a few cases of natural pregnancy and normal delivery following treatment for craniopharyngioma with hypothalamic extension have been reported. We will describe and discuss a case in which natural pregnancy and normal delivery occurred twice after such treatment.