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Sample records for bare uranium hexafluoride

  1. Fire testing of bare uranium hexafluoride cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Pryor, W.A. [PAI Corp., Oak Ridge, TN (United States)

    1991-12-31

    In 1965, the Oak Ridge Gaseous Diffusion Plant (ORGDP), now the K-25 Site, conducted a series of tests in which bare cylinders of uranium hexafluoride (UF{sub 6}) were exposed to engulfing oil fires for the US Atomic Energy Commission (AEC), now the US Department of Energy (DOE). The tests are described and the results, conclusions, and observations are presented. Two each of the following types of cylinders were tested: 3.5-in.-diam {times} 7.5-in.-long cylinders of Monel (Harshaw), 5.0-in.-diam {times} x 30-in.-long cylinders of Monel, and 8-in.-diam {times} 48-in.-long cylinders of nickel. The cylinders were filled approximately to the standard UF{sub 6} fill limits of 5, 55, and 250 lb, respectively, with a U-235 content of 0.22%. The 5-in.- and 8-in.-diam cylinders were tested individually with and without their metal valve covers. For the 3.5-in.-diam Harshaw cylinders and the 5.0-in.-diam cylinder without a valve cover, the valves failed and UF{sub 6} was released. The remaining 6 cylinders ruptured explosively in time intervals ranging from about 8.5 to 11 min.

  2. Fire testing of bare uranium hexafluoride cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Pryor, W.A. [PAI Corp., Oak Rige, TN (United States)

    1991-12-31

    In 1965, the Oak Ridge Gaseous Diffusion Plant (ORGDP), now the K-25 Site, conducted a series of tests in which bare cylinders of uranium hexafluoride (UF{sub 6}) were exposed to engulfing oil fires for the US Atomic Energy Commission (AEC), now the US Department of Energy (DOE). The tests are described and the results, conclusions, and observations are presented. Two each of the following types of cylinders were tested: 3.5-in.-diam {times} 7.5-in.-long cylinders of Monel (Harshaw), 5.0-in.-diam {times} 30-in.-long cylinders of Monel, and 8-in.-diam {times} 48-in.-long cylinders of nickel. The cylinders were filled approximately to the standard UF{sub 6} fill limits of 5, 55, and 250 lb, respectively, with a U-235 content of 0.22%. The 5-in.- and 8-in.-diam cylinders were tested individually with and without their metal valve covers. For the 3.5-in.-diam Harshaw cylinders and the 5.0-in.-diam cylinder without a valve cover the valves failed and UF{sub 6} was released. The remaining cylinders ruptured explosively in time intervals ranging from about 8.5 to 11 min.

  3. Uranium hexafluoride purification

    International Nuclear Information System (INIS)

    Uranium hexafluoride might contain a large amount of impurities after manufacturing or handling. Three usual methods of purification of uranium hexafluoride were presented: selective sorption, sublimation, and distillation. Since uranium hexafluoride usually is contaminated with hydrogen fluoride, a theoretical study of the phase equilibrium properties was performed for the binary system UF6-HF. A large deviation from the ideal solution behaviour was observed. A purification unity based on a constant reflux batch distillation process was developed. A procedure was established in order to design the re boiler, condenser and packed columns for the UF6-HF mixture separation. A bench scale facility for fractional distillation of uranium hexafluoride was described. Basic operations for that facility and results extracted from several batches were discussed. (author)

  4. Uranium hexafluoride handling

    International Nuclear Information System (INIS)

    The United States Department of Energy, Oak Ridge Field Office, and Martin Marietta Energy Systems, Inc., are co-sponsoring this Second International Conference on Uranium Hexafluoride Handling. The conference is offered as a forum for the exchange of information and concepts regarding the technical and regulatory issues and the safety aspects which relate to the handling of uranium hexafluoride. Through the papers presented here, we attempt not only to share technological advances and lessons learned, but also to demonstrate that we are concerned about the health and safety of our workers and the public, and are good stewards of the environment in which we all work and live. These proceedings are a compilation of the work of many experts in that phase of world-wide industry which comprises the nuclear fuel cycle. Their experience spans the entire range over which uranium hexafluoride is involved in the fuel cycle, from the production of UF6 from the naturally-occurring oxide to its re-conversion to oxide for reactor fuels. The papers furnish insights into the chemical, physical, and nuclear properties of uranium hexafluoride as they influence its transport, storage, and the design and operation of plant-scale facilities for production, processing, and conversion to oxide. The papers demonstrate, in an industry often cited for its excellent safety record, continuing efforts to further improve safety in all areas of handling uranium hexafluoride

  5. Uranium hexafluoride handling. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-31

    The United States Department of Energy, Oak Ridge Field Office, and Martin Marietta Energy Systems, Inc., are co-sponsoring this Second International Conference on Uranium Hexafluoride Handling. The conference is offered as a forum for the exchange of information and concepts regarding the technical and regulatory issues and the safety aspects which relate to the handling of uranium hexafluoride. Through the papers presented here, we attempt not only to share technological advances and lessons learned, but also to demonstrate that we are concerned about the health and safety of our workers and the public, and are good stewards of the environment in which we all work and live. These proceedings are a compilation of the work of many experts in that phase of world-wide industry which comprises the nuclear fuel cycle. Their experience spans the entire range over which uranium hexafluoride is involved in the fuel cycle, from the production of UF{sub 6} from the naturally-occurring oxide to its re-conversion to oxide for reactor fuels. The papers furnish insights into the chemical, physical, and nuclear properties of uranium hexafluoride as they influence its transport, storage, and the design and operation of plant-scale facilities for production, processing, and conversion to oxide. The papers demonstrate, in an industry often cited for its excellent safety record, continuing efforts to further improve safety in all areas of handling uranium hexafluoride. Selected papers were processed separately for inclusion in the Energy Science and Technology Database.

  6. Hydrolysis of uranium hexafluoride

    International Nuclear Information System (INIS)

    A literature survey is presented of uranium hexafluoride hydrolysis methods as the first step in UF6 conversion to UO2. Reviewed are early methods of hydrolysis, the hydrolysis by dry water vapour, the fluidized-bed method, and the liquid phase hydrolysis of UF6 gas. (J.P.)

  7. Diffusion of uranium hexafluoride

    Science.gov (United States)

    Winkelmann, J.

    This document is part of Subvolume A `Gases in Gases, Liquids and their Mixtures' of Volume 15 `Diffusion in Gases, Liquids and Electrolytes' of Landolt-Börnstein Group IV `Physical Chemistry'. It is part of the chapter of the chapter `Diffusion in Pure Gases' and contains data on diffusion of uranium hexafluoride

  8. Uranium hexafluoride bibliography

    Energy Technology Data Exchange (ETDEWEB)

    Burnham, S.L.

    1988-01-01

    This bibliography is a compilation of reports written about the transportation, handling, safety, and processing of uranium hexafluoride. An on-line literature search was executed using the DOE Energy files and the Nuclear Science Abstracts file to identify pertinent reports. The DOE Energy files contain unclassified information that is processed at the Office of Scientific and Technical Information of the US Department of Energy. The reports selected from these files were published between 1974 and 1983. Nuclear Science Abstracts contains unclassified international nuclear science and technology literature published from 1948 to 1976. In addition, scientific and technical reports published by the US Atomic Energy Commission and the US Energy Research and Development Administration, as well as those published by other agencies, universities, and industrial and research organizations, are included in the Nuclear Science Abstracts file. An alphabetical listing of the acronyms used to denote the corporate sponsors follows the bibliography.

  9. Uranium hexafluoride public risk

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, D.R.; Hui, T.E.; Yurconic, M.; Johnson, J.R.

    1994-08-01

    The limiting value for uranium toxicity in a human being should be based on the concentration of uranium (U) in the kidneys. The threshold for nephrotoxicity appears to lie very near 3 {mu}g U per gram kidney tissue. There does not appear to be strong scientific support for any other improved estimate, either higher or lower than this, of the threshold for uranium nephrotoxicity in a human being. The value 3 {mu}g U per gram kidney is the concentration that results from a single intake of about 30 mg soluble uranium by inhalation (assuming the metabolism of a standard person). The concentration of uranium continues to increase in the kidneys after long-term, continuous (or chronic) exposure. After chronic intakes of soluble uranium by workers at the rate of 10 mg U per week, the concentration of uranium in the kidneys approaches and may even exceed the nephrotoxic limit of 3 {mu}g U per gram kidney tissue. Precise values of the kidney concentration depend on the biokinetic model and model parameters assumed for such a calculation. Since it is possible for the concentration of uranium in the kidneys to exceed 3 {mu}g per gram tissue at an intake rate of 10 mg U per week over long periods of time, we believe that the kidneys are protected from injury when intakes of soluble uranium at the rate of 10 mg U per week do not continue for more than two consecutive weeks. For long-term, continuous occupational exposure to low-level, soluble uranium, we recommend a reduced weekly intake limit of 5 mg uranium to prevent nephrotoxicity in workers. Our analysis shows that the nephrotoxic limit of 3 {mu}g U per gram kidney tissues is not exceeded after long-term, continuous uranium intake at the intake rate of 5 mg soluble uranium per week.

  10. 31 CFR 540.318 - Uranium Hexafluoride (UF6).

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Uranium Hexafluoride (UF6). 540.318... CONTROL REGULATIONS General Definitions § 540.318 Uranium Hexafluoride (UF6). The term uranium hexafluoride or UF6 means a compound of uranium and fluorine....

  11. Uranium hexafluoride production plant decommissioning

    International Nuclear Information System (INIS)

    The Institute of Energetic and Nuclear Research - IPEN is a research and development institution, located in a densely populated area, in the city of Sao Paulo. The nuclear fuel cycle was developed from the Yellow Cake to the enrichment and reconversion at IPEN. After this phase, all the technology was transferred to private enterprises and to the Brazilian Navy (CTM/SP). Some plants of the fuel cycle were at semi-industrial level, with a production over 20 kg/h. As a research institute, IPEN accomplished its function of the fuel cycle, developing and transferring technology. With the necessity of space for the implementation of new projects, the uranium hexafluoride (UF6) production plant was chosen, since it had been idle for many years and presented potential leaking risks, which could cause environmental aggression and serious accidents. This plant decommission required accurate planning, as this work had not been carried out in Brazil before, for this type of facility, and there were major risks involving gaseous hydrogen fluoride aqueous solution of hydrofluoric acid (HF) both highly corrosive. Evaluations were performed and special equipment was developed, aiming to prevent leaking and avoid accidents. During the decommissioning work, the CNEN safety standards were obeyed for the whole operation. The environmental impact was calculated, showing to be not relevant.The radiation doses, after the work, were within the limits for the public and the area was released for new projects. (author)

  12. Multiphoton ionization of uranium hexafluoride

    International Nuclear Information System (INIS)

    Multiphoton ionization (MPI) time-of-flight mass spectroscopy (TOFMS) and photoelectron spectroscopy (PES) studies of UF6 are reported using focused light from the Nd:YAG laser fundamental (λ=1064 nm) and its harmonics (λ=532, 355, or 266 nm), as well as other wavelengths provided by a tunable dye laser. The MPI mass spectra are dominated by the singly and multiply charged uranium ions rather than by the UF+x fragment ions, even at the lowest laser power densities at which signal could be detected. In general, the doubly charged uranium ion (U2+) intensity is much greater than that of the singly charged uranium ion (U+). For the case of the tunable dye laser experiments, the Un+ (n=1--4) wavelength dependence is relatively unstructured and does not show observable resonance enhancement at known atomic uranium excitation wavelengths. The MPI-PES studies reveal only very slow electrons (≤0.5 eV) for all wavelengths investigated. The dominance of the U2+ ion, the absence or very small intensities of UF+x (x=1--3) fragments, the unstructured wavelength dependence, and the preponderance of slow electrons all indicate that mechanisms may exist other than ionization of bare U atoms following the stepwise photodissociation of F atoms from the parent molecule. The data also argue against stepwise photodissociation of UF+x (x=5,6) ions. Neither of the traditional MPI mechanisms (''neutral ladder'' or the ''ionic ladder'') are believed to adequately describe the ionization phenomena observed. We propose that the multiphoton excitation of UF6 under these experimental conditions results in a highly excited molecule, superexcited UF6**

  13. Decommissioning of an uranium hexafluoride pilot plant

    International Nuclear Information System (INIS)

    The Institute of Nuclear and Energetic Researches has completed fifty years of operation, belongs to the National Commission for Nuclear Energy, it is situated inside the city of Sao Paulo. The IPEN-CNEN/SP is a Brazilian reference in the nuclear fuel cycle, researches in this field began in 1970, having dominance in the cycle steps from Yellow Cake to Uranium Hexafluoride technology. The plant of Uranium Hexafluoride produced 35 metric tonnes of this gas by year, had been closed in 1992, due to domain and total transference of know-how for industrial scale, demand of new facilities for the improvement of recent researches projects. The Institute initiates decommissioning in 2002. Then, the Uranium Hexafluoride pilot plant, no doubt the most important unit of the fuel cycle installed at IPEN-CNEN/SP, beginning decommissioning and dismantlement (D and D) in 2005. Such D and D strategies, planning, assessment and execution are described, presented and evaluated in this paper. (author)

  14. Multiphoton ionization of uranium hexafluoride

    Science.gov (United States)

    Armstrong, D. P.; Harkins, D. A.; Compton, R. N.; Ding, D.

    1994-01-01

    Multiphoton ionization (MPI) time-of-flight mass spectroscopy (TOFMS) and photoelectron spectroscopy (PES) studies of UF6 are reported using focused light from the Nd:YAG laser fundamental (λ=1064 nm) and its harmonics (λ=532, 355, or 266 nm), as well as other wavelengths provided by a tunable dye laser. The MPI mass spectra are dominated by the singly and multiply charged uranium ions rather than by the UF+x fragment ions, even at the lowest laser power densities at which signal could be detected. In general, the doubly charged uranium ion (U2+) intensity is much greater than that of the singly charged uranium ion (U+). For the case of the tunable dye laser experiments, the Un+ (n=1-4) wavelength dependence is relatively unstructured and does not show observable resonance enhancement at known atomic uranium excitation wavelengths. The MPI-PES studies reveal only very slow electrons (≤0.5 eV) for all wavelengths investigated. The dominance of the U2+ ion, the absence or very small intensities of UF+x (x=1-3) fragments, the unstructured wavelength dependence, and the preponderance of slow electrons all indicate that mechanisms may exist other than ionization of bare U atoms following the stepwise photodissociation of F atoms from the parent molecule. The data also argue against stepwise photodissociation of UF+x (x=5,6) ions. Neither of the traditional MPI mechanisms (``neutral ladder'' or the ``ionic ladder'') are believed to adequately describe the ionization phenomena observed. We propose that the multiphoton excitation of UF6 under these experimental conditions results in a highly excited molecule, superexcited UF6**. The excitation of highly excited UF6** is proposed to be facilitated by the well known ``giant resonance,'' whose energy level lies in the range of 12-14 eV above that of ground state UF6. The highly excited molecule then primarily dissociates, via multiple channels, into Un+, UF+x, fluorine atoms, and ``slow'' electrons, although dissociation

  15. Depleted uranium hexafluoride: Waste or resource?

    Energy Technology Data Exchange (ETDEWEB)

    Schwertz, N.; Zoller, J.; Rosen, R.; Patton, S. [Lawrence Livermore National Lab., CA (United States); Bradley, C. [USDOE Office of Nuclear Energy, Science, Technology, Washington, DC (United States); Murray, A. [SAIC (United States)

    1995-07-01

    the US Department of Energy is evaluating technologies for the storage, disposal, or re-use of depleted uranium hexafluoride (UF{sub 6}). This paper discusses the following options, and provides a technology assessment for each one: (1) conversion to UO{sub 2} for use as mixed oxide duel, (2) conversion to UO{sub 2} to make DUCRETE for a multi-purpose storage container, (3) conversion to depleted uranium metal for use as shielding, (4) conversion to uranium carbide for use as high-temperature gas-cooled reactor (HTGR) fuel. In addition, conversion to U{sub 3}O{sub 8} as an option for long-term storage is discussed.

  16. Plasma hydrogen reduction of uranium from depleted uranium hexafluoride

    International Nuclear Information System (INIS)

    Process scheme of plasma hydrogen reduction of waste by 235U uranium hexafluoride, preparation of metal uranium and anhydrous hydrogen fluoride is proposed. Results of the experimental investigations into the basic stages of this process scheme: production of the U - F - H-plasma, production and separation of uranium melt and anhydrous of hydrogen fluoride are treated. Level of plasma and high frequency technique for the realization of the plasma hydrogen process of conversion of waste UF6 for metal uranium and anhydrous HF was analyzed

  17. Hazard analysis in uranium hexafluoride production facility

    International Nuclear Information System (INIS)

    The present work provides a method for preliminary hazard analysis of nuclear fuel cycle facilities. The proposed method identify both chemical and radiological hazards, as well as the consequences associated with accident scenarios. To illustrate the application of the method, a uranium hexafluoride production facility was selected. The main hazards are identified and the potential consequences are quantified. It was found that, although the facility handles radioactive material, the main hazards as associated with releases of toxic chemical substances such as hydrogen fluoride, anhydrous ammonia and nitric acid. It was shown that a contention bung can effectively reduce the consequences of atmospheric release of toxic materials. (author)

  18. Metastable ions in mass spectrum of uranium hexafluoride

    International Nuclear Information System (INIS)

    Using MI-1201 AGM time-of-flight spectrometer one measured mass-spectrum of natural isotopic composition uranium hexafluoride. One recorded occurrence of essential amount (∼ 0.3%) amount of metastable ions in uranium hexafluoride spectrum. Apparent masses of metastable ions calculated on the basis of the reference masses of uranium hexafluoride fission-produced ions are close to values predicted by calculation. Metastable ions are shown to be the basic reason of background ion current within mass wide range. One evaluated lifetime of metastable ions with 333 mass (UF5)

  19. The great accidents of uranium hexafluoride in the world

    International Nuclear Information System (INIS)

    In two previous articles (Preventique Securite number 77 and 78) devoted for the first one to the uranium hexafluoride molecules, the second one to some experiments realised with this product was tackled a subject less known by the public. In this issue is presented an experience feedback worthy of being saved. An accident during transport of uranium hexafluoride by train with a fire is reported. Japan professors come in France to study the safety of uranium hexafluoride safety asked questions about spiteful actions, specially in tunnels. The question of terrorism was not included in the safety studies at this time but nowadays it is a parameter that cannot be dismissed. (N.C.)

  20. Simple pressure gauge for uranium hexafluoride.

    Science.gov (United States)

    George, P M; Swanson, M N; Beauchamp, J L

    1979-12-01

    A sensitive detector and pressure gauge for uranium hexafluoride in high-vacuum systems is described. Negative surface ionization of UF(6) occurs on ribbon filaments operated at temperatures too low for electron emission to be significant. The ion current measured on a cylindrical collector surrounding the filament assembly varies regularly with UF(6) pressure below 10(-3) Torr. Different filament materials are considered, including rhenium, thoriated tungsten, and platinum. Rhenium is found to be the most satisfactory material for operation of diode emitters as a pressure gauge. Gauge constants (in A Torr(-1)) are derived from comparing negative surface ionization currents with the response of a capacitance manometer and are shown to be independent of temperature within a reasonable operating range. The effects of exposing the rhenium filament to various gases is considered, and it is shown that brief exposure to acetylene substantially improves the operating characteristics of the gauge. PMID:18699453

  1. Uranium hexafluoride: Handling procedures and container descriptions

    International Nuclear Information System (INIS)

    The US Department of Energy (DOE) guidelines for packaging, measuring, and transferring uranium hexafluoride (UF6) have been undergoing continual review and revision for several years to keep them in phase with developing agreements for the supply of enriched uranium. Initially, K-1323 ''A Brief Guide to UF6 Handling,'' was issued in 1957. This was superceded by ORO-651, first issued in 1966, and reissued in 1967 to make editorial changes and to provide minor revisions in procedural information. In 1968 and 1972, Revisions 2 and 3, respectively, were issued as part of the continuing effort to present updated information. Revision 4 issued in 1977 included revisions to UF6 cylinders, valves, and methods to use. Revision 5 adds information dealing with pigtails, overfilled cylinders, definitions and handling precautions, and cylinder heel reduction procedures. Weighing standards previously presented in ORO-671, Vol. 1 (Procedures for Handling and Analysis of UF6) have also been included. This revision, therefore, supercedes ORO-671-1 as well as all prior issues of this report. These guidelines will normally apply in all transactions involving receipt or shipment of UF6 by DOE, unless stipulated otherwise by contracts or agreements with DOE or by notices published in the Federal Register. Any questions or requests for additional information on the subject matter covered herein should be directed to the United States Department of Energy, P.O. Box E, Oak Ridge, Tennessee 37831, Attention: Director, Uranium Enrichment Operations Division. 33 figs., 12 tabs

  2. Test emission of uranium hexafluoride in atmosphere. Results interpretation

    International Nuclear Information System (INIS)

    To permit the modelization of gaseous uranium hexafluoride behaviour in atmosphere, a validation test has been executed the 10 April 1987. The experimental conditions, the main results and a comparison with a diffusion model are given in this report

  3. Uranium hexafluoride purification; Purificacao de hexafluoreto de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Eneas F. de

    1986-07-01

    Uranium hexafluoride might contain a large amount of impurities after manufacturing or handling. Three usual methods of purification of uranium hexafluoride were presented: selective sorption, sublimation, and distillation. Since uranium hexafluoride usually is contaminated with hydrogen fluoride, a theoretical study of the phase equilibrium properties was performed for the binary system UF{sub 6}-HF. A large deviation from the ideal solution behaviour was observed. A purification unity based on a constant reflux batch distillation process was developed. A procedure was established in order to design the re boiler, condenser and packed columns for the UF{sub 6}-HF mixture separation. A bench scale facility for fractional distillation of uranium hexafluoride was described. Basic operations for that facility and results extracted from several batches were discussed. (author)

  4. Raoult's Law Study of Vanadium Pentafluoride in Uranium Hexafluoride.

    Science.gov (United States)

    Shrewsberry, R C; Musulin, B

    1964-09-25

    Binary systems of liquid vanadium pentafluoride dissolved in liquid uranium hexafluoride are non-ideal, with negative deviations from Raoult's law in the temperature range 75 degrees to 92 degrees C. PMID:17838706

  5. Trimolecular reactions of uranium hexafluoride with water.

    Science.gov (United States)

    Lind, Maria C; Garrison, Stephen L; Becnel, James M

    2010-04-01

    The hydrolysis reaction of uranium hexafluoride (UF(6)) is a key step in the synthesis of uranium dioxide (UO(2)) powder for nuclear fuels. Mechanisms for the hydrolysis reactions are studied here with density functional theory and the Stuttgart small-core scalar relativistic pseudopotential and associated basis set for uranium. The reaction of a single UF(6) molecule with a water molecule in the gas phase has been previously predicted to proceed over a relatively sizable barrier of 78.2 kJ x mol(-1), indicating this reaction is only feasible at elevated temperatures. Given the observed formation of a second morphology for the UO(2) product coupled with the observations of rapid, spontaneous hydrolysis at ambient conditions, an alternate reaction pathway must exist. In the present work, two trimolecular hydrolysis mechanisms are studied with density functional theory: (1) the reaction between two UF(6) molecules and one water molecule, and (2) the reaction of two water molecules with a single UF(6) molecule. The predicted reaction of two UF(6) molecules with one water molecule displays an interesting "fluorine-shuttle" mechanism, a significant energy barrier of 69.0 kJ x mol(-1) to the formation of UF(5)OH, and an enthalpy of reaction (DeltaH(298)) of +17.9 kJ x mol(-1). The reaction of a single UF(6) molecule with two water molecules displays a "proton-shuttle" mechanism, and is more favorable, having a slightly lower computed energy barrier of 58.9 kJ x mol(-1) and an exothermic enthalpy of reaction (DeltaH(298)) of -13.9 kJ x mol(-1). The exothermic nature of the overall UF(6) + 2H(2)O trimolecular reaction and the lowering of the barrier height with respect to the bimolecular reaction are encouraging. PMID:20210345

  6. The multiphoton ionization of uranium hexafluoride

    International Nuclear Information System (INIS)

    Multiphoton ionization (MPI) time-of-flight mass spectroscopy and photoelectron spectroscopy studies of UF6 have been conducted using focused light from the Nd:YAG laser fundamental (λ=1064 nm) and its harmonics (λ=532, 355, or 266 nm), as well as other wavelengths provided by a tunable dye laser. The MPI mass spectra are dominated by the singly and multiply charged uranium ions rather than by the UFx+ fragment ions even at the lowest laser power densities at which signal could be detected. The laser power dependence of Un+ ions signals indicates that saturation can occur for many of the steps required for their ionization. In general, the doubly-charged uranium ion (U2+) intensity is much greater than that of the singly-charged uranium ion (U+). For the case of the tunable dye laser experiments, the Un+ (n = 1- 4) wavelength dependence is relatively unstructured and does not show observable resonance enhancement at known atomic uranium excitation wavelengths. The dominance of the U2+ ion and the absence or very small intensities of UFx+ fragments, along with the unsaturated wavelength dependence, indicate that mechanisms may exist other than ionization of bare U atoms after the stepwise photodissociation of F atoms from the parent molecule

  7. Uranium hexafluoride cylinders survive train derailment

    International Nuclear Information System (INIS)

    A serious train derailment took place in North Carolina in March of 1977. Two of the twenty-nine cars which went off the tracks carried radioactive materials in the form of natural uranium hexafluoride - UF6(N). The packaging for this low specific activity material is a 48 inch diameter by 12.5 foot long cylinder constructed of 5/8 inch thick steel. Each of the four cylinders contained approximately 12,500 kg of UF6(N). The cylinders were mounted on steel cradles which were securely fastened to trailers which in turn were riding on flatcars in standard piggyback fashion. All four of the trailers and cylinders were damaged. The condition of each cylinder immediately after the accident, the recovery and subsequent shipment to Oak Ridge, the receipt inspection and the final disposition of the cylinders and the contents are described in the paper. The immediate response of the media to the news that radioactive material was on the train resulted in a great deal of misinformation being disseminated. In contrast to the initial reports of leakage, there was no breach of the containers and no radioactive contamination of any kind. The National Transportation Safety Board has issued a report on the accident recommending development of guidelines for emergency response procedures

  8. Update on packaging for uranium hexafluoride transport

    International Nuclear Information System (INIS)

    The slightly enriched product, Uranium Hexafluoride (UF6), shipped from the enriching plants for the worlds nuclear power plants, must be protected in order to conform to domestic and international transport regulations. The principal overpack currently in use is the US Department of Transportation (USDOT) Specification 21PF-1, which protects Model 30 UF6 cylinders (Title 49, Code of Federal Regulations; Part 178.121, Specification 21PF-1 fire and shock resistant, phenolic - foam insulated overpack (horizontal loading)). Operational problems have developed due to both design and lack of maintenance, resulting in the entry of water into the insulation zone. Following major review of these problems, particularly those concerned with water entry and general deterioration, the design was re-examined and modified. A composite proposal for modification and supporting documentation is described in the Proposal for Modification to USDOT 21PF-1 Fire and Shock Resistant Phenolic Foam - Insulated Overpacks. The proposal was submitted to USDOT by the US Department of Energy (USDOE) as a petition to revise the DOT Specification for the 21PF-1. The petition was generally accepted by the USDOT, and the design changes and a final rule were published in the Federal Register on September 20, 1988

  9. TRIMOLECULAR REACTIONS OF URANIUM HEXAFLUORIDE WITH WATER

    Energy Technology Data Exchange (ETDEWEB)

    Westbrook, M.; Becnel, J.; Garrison, S.

    2010-02-25

    The hydrolysis reaction of uranium hexafluoride (UF{sub 6}) is a key step in the synthesis of uranium dioxide (UO{sub 2}) powder for nuclear fuels. Mechanisms for the hydrolysis reactions are studied here with density functional theory and the Stuttgart small-core scalar relativistic pseudopotential and associated basis set for uranium. The reaction of a single UF{sub 6} molecule with a water molecule in the gas phase has been previously predicted to proceed over a relatively sizeable barrier of 78.2 kJ {center_dot} mol{sup -1}, indicating this reaction is only feasible at elevated temperatures. Given the observed formation of a second morphology for the UO{sub 2} product coupled with the observations of rapid, spontaneous hydrolysis at ambient conditions, an alternate reaction pathway must exist. In the present work, two trimolecular hydrolysis mechanisms are studied with density functional theory: (1) the reaction between two UF{sub 6} molecules and one water molecule, and (2) the reaction of two water molecules with a single UF{sub 6} molecule. The predicted reaction of two UF{sub 6} molecules with one water molecule displays an interesting 'fluorine-shuttle' mechanism, a significant energy barrier of 69.0 kJ {center_dot} mol{sup -1} to the formation of UF{sub 5}OH, and an enthalpy of reaction ({Delta}H{sub 298}) of +17.9 kJ {center_dot} mol{sup -1}. The reaction of a single UF{sub 6} molecule with two water molecules displays a 'proton-shuttle' mechanism, and is more favorable, having a slightly lower computed energy barrier of 58.9 kJ {center_dot} mol{sup -1} and an exothermic enthalpy of reaction ({Delta}H{sub 298}) of -13.9 kJ {center_dot} mol{sup -1}. The exothermic nature of the overall UF{sub 6} + 2 {center_dot} H{sub 2}O trimolecular reaction and the lowering of the barrier height with respect to the bimolecular reaction are encouraging; however, the sizable energy barrier indicates further study of the UF{sub 6} hydrolysis reaction

  10. The multiphoton ionization of uranium hexafluoride

    International Nuclear Information System (INIS)

    Multiphoton ionization (MPI) time-of-flight mass spectroscopy and photoelectron spectroscopy studies of UF6 have been conducted using focused light from the Nd:YAG laser fundamental (λ = 1064 nm) and its harmonics (λ = 532, 355, or 266 nm), as well as other wavelengths provided by a tunable dye laser. The MPI mass spectra are dominated by the singly and multiply charged uranium ions rather than by the UFx+ fragment ions. The laser power dependence of Un+ ion signals indicates that saturation can occur for many of the steps required for their ionization. The doubly-charged uranium ion (U2+) intensity is much greater than that of the singly-charged uranium ion (U+). For the case of the tunable dye laser experiments, the Un+ (n=1-4) wavelength dependence is relatively unstructured and does not show observable resonance enhancement at known atomic uranium excitation wavelengths. The dominance of the U2+ ion and the absence or very small intensities of UFx+ fragments, along with the unstructured wavelength dependence, indicate that mechanisms may exist other than ionization of bare U atoms after the stepwise photodissociation of F atoms from the parent molecule. The data argue against step-wise photodissociation of UFx+ (x = 5,6) ions. Neither the neutral ladder nor the ion ladder mechanisms adequately describe the ionization phenomena observed. These results suggest an alternate mechanism which better explains the multiphoton excitation and dissociative ionization of UF6. It is likely that the multiphoton excitation of UF6 under these experimental conditions results in a superexcited molecule, UF6**, which primarily dissociates into Un+ (through multiple channels), fluorine atoms, and slow electrons. The excitation of such superexcited molecules may be facilitated by the existence of a previously reported giant resonance at 12-14 eV

  11. Investigation of an r-f radiant energy source with uranium hexafluoride and tungsten hexafluoride injection.

    Science.gov (United States)

    Roman, W. C.

    1971-01-01

    An experimental investigation was conducted using the UARL 1.2-megw r-f induction heater to simulate thermal environment and fuel region characteristics expected in nuclear light bulb reactors. Argon was injected at the ends of the test chamber to provide radial-inflow vortex flow pattern. In some tests, simulated fuel consisting of a mixture of argon gas with either tungsten hexafluoride gas, uranium hexafluoride gas, or tungsten particles was injected into the discharge region from probes located at the centers of the end walls. The encouraging initial results obtained are discussed.

  12. Plasma beam processing of uranium hexafluoride - process energetics and design

    International Nuclear Information System (INIS)

    Plasma chemical technique provides an excellent alternative and possible improvement in the reprocessing of depleted uranium hexafluoride in the nuclear fuel cycle. The paper presents the conceptual design options of the complete system including the plasma torch, input system, reaction chamber, collection system etc. The basic thermodynamic calculations indicating the preferred operating regime are presented

  13. Fluorine solubility in liquid hexafluorides of uranium, tungsten and molybdenum

    International Nuclear Information System (INIS)

    Experimental data on fluorine solubility in liquid uranium, tungsten and molybdenum hexafluorides in the range 66-90 Deg C and fluorine partial pressure 226-1066 kPa are performed. Calculation values of the Henry constant for these systems and equilibrium constants of approximation by linearization of Henry constant temperature dependence are given

  14. Vacuum ultraviolet spectra of uranium hexafluoride/argon mixtures

    Science.gov (United States)

    Krascella, N. L.

    1976-01-01

    The transmission properties of room temperature helium at pressures up to 20 atmospheres were determined in the wavelength range from 80 to 300 nm. Similarly, the transmission properties of uranium hexafluoride at 393 K (pressures less than 1.0 mm) were determined in the wavelength range from 80 to about 120 nm. The results show that high pressure helium is sufficiently transparent in the vacuum ultraviolet region (provided trace contaminants are removed) to be utilized as a transparent purge gas in future fissioning gaseous uranium plasma reactor experiments. Absorption cross sections for uranium hexafluoride were calculated from the data between 80 and 120 nm and were of the order of 10 to the -17 power sq cm.

  15. On the photodissociation of uranium hexafluoride in the B band

    Science.gov (United States)

    Menghini, M.; Morales, P.; Dore, P.; Schisano, M. I.

    1986-06-01

    The rate of photodissociation of uranium hexafluoride is measured for the first time as a function of wavelength in the B band. The experimental technique used tests the collision-free behavior and, with the addition of a buffer gas, the collisional effects on molecular relaxation. In both cases, the dissociation yield is strongly nonuniform. A qualitative interpretation of these results is attempted. Their relevance to the subject of laser isotopic separation and more generally of selective photochemistry is outlined.

  16. Certification of the uranium hexafluoride reference materials for isotopic composition

    OpenAIRE

    MIALLE SÉBASTIEN; Richter, Stephan; HENNESSY Carmel; TRUYENS Jan; Jakobsson, Ulf; Aregbe, Yetunde

    2014-01-01

    The IRMM-019 to IRMM-029 series of uranium hexafluoride materials is certified for the isotopic composition. After conversion into uranyl nitrate solution, certification and homogeneity measurements were performed by Thermal Ionization Mass Spectrometry. Analyses were performed by Modified Total Evaporation and for some materials the major isotope amount ratio n(235U)/n(238U) was measured using a n(233U)/n(236U) double spike. Measurements were confirmed by UF6 Gas Source Mass Spectrometry. Ma...

  17. Study of the measurement about the apparent heat transfer coefficient of solid uranium hexafluoride

    International Nuclear Information System (INIS)

    In order to provide the conditions for designing the congealed accept container of uranium hexafluoride, a set of experiment system of measuring apparent heat transfer coefficient in which the small-sized congealed accept container was considered as main equipment was set up. Then the experiments of loading and unloading uranium hexafluoride were carried out. The process of loading and unloading uranium hexafluoride in small-sized congealed accept container were simulated by the barrel model of steady heat transfer in this paper, and the apparent heat transfer coefficient of solid uranium hexafluoride was obtained. (authors)

  18. A review of laser isotope separation of uranium hexafluoride

    International Nuclear Information System (INIS)

    There is continuing world-wide interest in the possibility of enriching uranium by a laser process which uses uranium hexafluoride. Since no actual commercial plant exists at present, this review examines the key areas of related research. It concludes that such a process is feasible, that it must employ an adiabatic cooling system, with UF6 the minor constituent in a predominantly monatomic or diatomic carrier gas, that the necessary infrared and/or ultraviolet-visible lasers are in a state of development bordering on the minimum required, and that the economics of such a process appear highly promising

  19. Acute toxicity of uranium hexafluoride, uranyl fluoride and hydrogen fluoride

    International Nuclear Information System (INIS)

    Uranium hexafluoride (UF6) released into the atmosphere will react rapidly with moisture in the air to form the hydrolysis products uranyl fluoride (UO2F2) and hydrogen fluoride (HF). Uranium compounds such as UF6 and UO2F2 exhibit both chemical toxicity and radiological effects, while HF exhibits only chemical toxicity. This paper describes the development of a methodology for assessing the human health consequences of a known acute exposure to a mixture of UF6, UO2F2, and HF. 4 refs., 2 figs., 5 tabs

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

    International Nuclear Information System (INIS)

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

  1. [Theoretic evaluation of allowable time for evacuation from occupational zone of accidentally released uranium hexafluoride].

    Science.gov (United States)

    Babenko, S P

    2005-01-01

    Transdermal intake of uranium hexafluoride hydrolysis products is analysed. The authors present calculations of uranium and fluor amounts entering human body, in accordance with duration of stay in hazardous circumstances. PMID:16381480

  2. Corrosion of copper alloys by gaseous uranium hexafluoride

    International Nuclear Information System (INIS)

    The corrosion of electrolytic copper and eight copper alloys in gaseous uranium hexafluoride at a pressure of 15 kPa was investigated. Corrosion-time relationships were established for five temperatures ranging from 50 to 150oC and for exposure times between 5 and 1000 h. Post-corrosion investigations were performed, employing a variety of physical techniques. Electrolytic copper, beryllium copper, and aluminium bronze were found to be the most resistant of the alloys investigated. The uranium containing corrosion products found were the α and β forms of UF5 and U2F9, with the more reactive alloys giving rise to U2F9. Changes in corrosion mechanism correlated with changes in the intermediate uranium fluoride formed. Corrosion activation energies were low, compared to conventional oxidation, ranging from 4 to 64 kJ mol-1. (Author)

  3. Depleted uranium hexafluoride: The source material for advanced shielding systems

    Energy Technology Data Exchange (ETDEWEB)

    Quapp, W.J.; Lessing, P.A. [Idaho National Engineering Lab., Idaho Falls, ID (United States); Cooley, C.R. [Department of Technology, Germantown, MD (United States)

    1997-02-01

    The U.S. Department of Energy (DOE) has a management challenge and financial liability problem in the form of 50,000 cylinders containing 555,000 metric tons of depleted uranium hexafluoride (UF{sub 6}) that are stored at the gaseous diffusion plants. DOE is evaluating several options for the disposition of this UF{sub 6}, including continued storage, disposal, and recycle into a product. Based on studies conducted to date, the most feasible recycle option for the depleted uranium is shielding in low-level waste, spent nuclear fuel, or vitrified high-level waste containers. Estimates for the cost of disposal, using existing technologies, range between $3.8 and $11.3 billion depending on factors such as the disposal site and the applicability of the Resource Conservation and Recovery Act (RCRA). Advanced technologies can reduce these costs, but UF{sub 6} disposal still represents large future costs. This paper describes an application for depleted uranium in which depleted uranium hexafluoride is converted into an oxide and then into a heavy aggregate. The heavy uranium aggregate is combined with conventional concrete materials to form an ultra high density concrete, DUCRETE, weighing more than 400 lb/ft{sup 3}. DUCRETE can be used as shielding in spent nuclear fuel/high-level waste casks at a cost comparable to the lower of the disposal cost estimates. Consequently, the case can be made that DUCRETE shielded casks are an alternative to disposal. In this case, a beneficial long term solution is attained for much less than the combined cost of independently providing shielded casks and disposing of the depleted uranium. Furthermore, if disposal is avoided, the political problems associated with selection of a disposal location are also avoided. Other studies have also shown cost benefits for low level waste shielded disposal containers.

  4. Uranium hexafluoride: Safe handling, processing, and transporting: Conference proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Strunk, W.D.; Thornton, S.G. (eds.)

    1988-01-01

    This conference seeks to provide a forum for the exchange of information and ideas of the safety aspects and technical issue related to the handling of uranium hexafluoride. By allowing operators, engineers, scientists, managers, educators, and others to meet and share experiences of mutual concern, the conference is also intended to provide the participants with a more complete knowledge of technical and operational issues. The topics for the papers in the proceedings are widely varied and include the results of chemical, metallurgical, mechanical, thermal, and analytical investigations, as well as the developed philosophies of operational, managerial, and regulatory guidelines. Papers have been entered individually into EDB and ERA. (LTN)

  5. Uranium hexafluoride: Safe handling, processing, and transporting: Conference proceedings

    International Nuclear Information System (INIS)

    This conference seeks to provide a forum for the exchange of information and ideas of the safety aspects and technical issue related to the handling of uranium hexafluoride. By allowing operators, engineers, scientists, managers, educators, and others to meet and share experiences of mutual concern, the conference is also intended to provide the participants with a more complete knowledge of technical and operational issues. The topics for the papers in the proceedings are widely varied and include the results of chemical, metallurgical, mechanical, thermal, and analytical investigations, as well as the developed philosophies of operational, managerial, and regulatory guidelines. Papers have been entered individually into EDB and ERA

  6. Study of the molecular structure of uranium hexafluoride

    International Nuclear Information System (INIS)

    The vibrational spectrum of uranium hexafluoride has been studied in both the gaseous and solid states. The study of gaseous UF6 confirms the regular octahedral structure of the fluorine atoms around the central U atom and makes it possible to evaluate some of the vibrational frequencies. From these, some new force constants have been determined. A tetragonal distortion is observed on solid UF6; this distortion has only observed up till now by means of X-ray diffraction and nuclear magnetic resonance techniques. (author)

  7. Sequoyah Uranium Hexafluoride Plant (Docket No. 40-8027): Final environmental statement

    International Nuclear Information System (INIS)

    The proposed action is the continuation of Source Material License SUB-1010 issued to Kerr-McGee Nuclear Corporation authorizing the operation of a uranium hexafluoride manufacturing facility located in Sequoyah County, Oklahoma, close to the confluence of the Illinois and Arkansas Rivers. The plant produces high purity uranium hexafluoride using uranium concentrates (yellowcake) as the starting material. It is currently designed to produce 5000 tons of uranium per year as uranium hexafluoride and has been in operation since February 1970 without significant environmental incident or discernible offsite effect. The manufacturing process being used includes wet chemical purification to convert yellowcake to pure uranium trioxide followed by dry chemical reduction, hydrofluorination, and fluorination technique to produce uranium hexafluoride. 8 figs, 12 tabs

  8. Parametric analyses of planned flowing uranium hexafluoride critical experiments

    Science.gov (United States)

    Rodgers, R. J.; Latham, T. S.

    1976-01-01

    Analytical investigations were conducted to determine preliminary design and operating characteristics of flowing uranium hexafluoride (UF6) gaseous nuclear reactor experiments in which a hybrid core configuration comprised of UF6 gas and a region of solid fuel will be employed. The investigations are part of a planned program to perform a series of experiments of increasing performance, culminating in an approximately 5 MW fissioning uranium plasma experiment. A preliminary design is described for an argon buffer gas confined, UF6 flow loop system for future use in flowing critical experiments. Initial calculations to estimate the operating characteristics of the gaseous fissioning UF6 in a confined flow test at a pressure of 4 atm, indicate temperature increases of approximately 100 and 1000 K in the UF6 may be obtained for total test power levels of 100 kW and 1 MW for test times of 320 and 32 sec, respectively.

  9. Selection of a management strategy for depleted uranium hexafluoride

    International Nuclear Information System (INIS)

    A consequence of the uranium enrichment process used in the United States (US) is the accumulation of a significant amount of depleted uranium hexafluoride (UF6). Currently, approximately 560,000 metric tons of the material are stored at three different sites. The US Department of Energy (DOE) has recently initiated a program to consider alternative strategies for the cost-effective and environmentally safe long-term management of this inventory of depleted UF6. The program involves a technology and engineering assessment of proposed management options (use/reuse, conversion, storage, or disposal) and an analysis of the potential environmental impacts and life-cycle costs of alternative management strategies. The information obtained from the studies will be used by the DOE to select a preferred long-term management strategy. The selection and implementation of a management strategy will involve consideration of a number of important issues such as environmental, health, and safety effects; the balancing of risks versus costs in a context of reduced government spending; socioeconomic implications, including effects on the domestic and international uranium industry; the technical status of proposed uses or technologies; and public involvement in the decision making process. Because of its provisions for considering a wide range of relevant issues and involving the public, this program has become a model for future DOE materials disposition programs. This paper presents an overview of the Depleted Uranium Hexafluoride Management Program. Technical findings of the program to date are presented, and major issues involved in selecting and implementing a management strategy are discussed

  10. Isotopic analysis of uranium hexafluoride highly enriched in U-235

    International Nuclear Information System (INIS)

    Isotopic analysis of uranium in the form of the hexafluoride by mass-spectrometry gives gross results which are not very accurate. Using a linear interpolation method applied to two standards it is possible to correct for this inaccuracy as long as the isotopic concentrations are less than about 10 per cent in U-235. Above this level, the interpolations formula overestimates the results, especially if the enrichment of the analyzed samples is higher than 1.3 with respect to the standards. A formula is proposed for correcting the interpolation equation and for the extending its field of application to high values of the enrichment (≅2) and of the concentration. It is shown that by using this correction the results obtained have an accuracy which depends practically only on that of the standards, taking into account the dispersion in the measurements. (authors)

  11. Certification of uranium hexafluoride reference materials for isotopic composition

    International Nuclear Information System (INIS)

    The IRMM-019 to IRMM-029 series of uranium hexafluoride materials is certified for the isotopic composition. After conversion into uranyl nitrate solution, certification and homogeneity measurements were performed by thermal ionization mass spectrometry. Analyses were performed by Modified Total Evaporation and for some materials the major isotope amount ratio n(235U)/n(238U) was measured using a n(233U)/n(236U) double spike. Measurements were confirmed by UF6 gas source mass spectrometry. Major isotope amount ratios were certified with relative expanded uncertainties (k = 2) of 0.015-0.030 % and the minor isotope amount ratios n(234U)/n(238U) and n(236U)/n(238U) were certified with relative expanded uncertainties of 0.02-3 %. (author)

  12. Dynamic tests for qualifying of national uranium hexafluoride

    International Nuclear Information System (INIS)

    The dynamic behaviour of the Brazilian uranium hexafluoride is analyzed in this paper, with regard to its radiolytic decomposition and to the action of catalysts on the reaction between UF6 and H2. The process gas (UF6/H2) was submitted in the laboratory of dynamic tests (DV-II) to similar conditions as those used in the enrichment plant presently being erected in Resende - RJ, 'First Cascade - FC'. The tests carried out have shown that the Brazilian UF6 has the same dynamic behaviour of the German UF6. It does not contain either any catalyst of the reaction between UF6 and H2 which could render it inappropriate for use in commercial plants. (author)

  13. Reactions of methyl and ethyl radicals with uranium hexafluoride

    Science.gov (United States)

    Lyman, John L.; Laguna, Glenn

    1985-01-01

    We have measured the rates of reaction of both methyl and ethyl radicals with uranium hexafluoride (UF6) in the gas phase. The method we used was to photolyze samples of UF6 in the presence of either methane or ethane. The radicals produced by reaction of fluorine atoms with these species then react with either themselves or with UF6. We inferred the rate constants from ratios of the reaction products and the published rate constants for radical recombination. The diagnostic technique was gas chromatography. The resulting rate constants for reaction with UF6 were (1.6±0.8)×10-14 cm3 molecule-1 s-1 for methyl radicals and (4±2)×10-11 cm3 molecule-1 s-1 for ethyl radicals.

  14. Direct measurement of uranium 235 concentration in uranium hexafluoride containers

    International Nuclear Information System (INIS)

    A simple, portable and autonomous apparatus is described. Isotopic ratio of uranium 235 can be determined in UF6 containers (type 30B or 48Y) without contact with the fissile material. A thermal neutron source induces, through the container wall, nuclear fissions. Fast neutrons produced by the nuclear reaction are detected and counted giving the concentration in uranium 235. Results obtained are presented and discussed

  15. Process for producing uranium oxide from uranium hexafluoride

    International Nuclear Information System (INIS)

    The blast furnace is divided into two parts. The conversion of the uranium fluoride vapour with dry steam into uranylfluoride powder occurs in the lower part. This powder is transported to the upper part of the blast furnace by a screw conveyor. In the upper part, which may be made in the form of a drum shaped rotating blast furnace, the conversion of the uranylfluoride with steam or hydrogen into uranium oxide takes place in counterflow. (DG)

  16. Standard guide for the determination of uranium-232 in uranium hexafluoride

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2006-01-01

    1.1 This method covers the determination of 232U in uranium hexafluoride by alpha spectrometry. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use.

  17. Standard test methods for arsenic in uranium hexafluoride

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 These test methods are applicable to the determination of total arsenic in uranium hexafluoride (UF6) by atomic absorption spectrometry. Two test methods are given: Test Method A—Arsine Generation-Atomic Absorption (Sections 5-10), and Test Method B—Graphite Furnace Atomic Absorption (Appendix X1). 1.2 The test methods are equivalent. The limit of detection for each test method is 0.1 μg As/g U when using a sample containing 0.5 to 1.0 g U. Test Method B does not have the complete collection details for precision and bias data thus the method appears as an appendix. 1.3 Test Method A covers the measurement of arsenic in uranyl fluoride (UO2F2) solutions by converting arsenic to arsine and measuring the arsine vapor by flame atomic absorption spectrometry. 1.4 Test Method B utilizes a solvent extraction to remove the uranium from the UO2F2 solution prior to measurement of the arsenic by graphite furnace atomic absorption spectrometry. 1.5 Both insoluble and soluble arsenic are measured when UF6 is...

  18. Spectral properties of gaseous uranium hexafluoride at high temperature

    Science.gov (United States)

    Krascella, N. L.

    1980-02-01

    A study to determine relative spectral emission and spectral absorption data for UF6-argon mixtures at elevated temperatures is discussed. These spectral data are required to assist in the theoretical analysis of radiation transport in the nuclear fuel-buffer gas region of a plasma core reactor. Relative emission measurements were made for UF6-argon mixtures over a range of temperatures from 650 to 1900 K and in the wavelength range from 600 to 5000 nanometers. All emission results were determined for a total pressure of 1.0 atm. Uranium hexafluoride partial pressures varied from about 3.5 to 12.7 mm Hg. Absorption measurements were attempted at 600, 625, 650 and 675 nanometers for a temperature of 1000 K. The uranium partial pressure for these determinations was 25 mm Hg. The results exhibit appreciable emission for hot UF6-argon mixtures at wavelengths between 600 and 1800 nanometers and no measurable absorption. The equipment used to evaluate the spectral properties of the UF6-argon mixtures included a plasma torch-optical plenum assembly, the monochromator, and the UF6 transfer system. Each is described.

  19. World War II uranium hexafluoride inhalation event with pulmonary implications for today

    International Nuclear Information System (INIS)

    Two individuals were exposed to massive quantities of airborne uranium hexafluoride (UF6) and its hydrolysis products following a World War II equipment rupture. An excretion pattern for uranium exhibited by these patients is, in light of current knowledge, anomalous. The possible role of pulmonary edema is discussed. Examination of these individuals 38 years later showed no physical changes believed to be related to their uranium exposure and no deposition of uranium could be detected

  20. A World War II uranium hexafluoride inhalation event with pulmonary implications for today.

    Science.gov (United States)

    Moore, R H; Kathren, R L

    1985-10-01

    Two individuals were exposed to massive quantities of airborne uranium hexafluoride (UF6) and its hydrolysis products following a World War II equipment rupture. An excretion pattern for uranium exhibited by these patients is, in light of current knowledge, anomalous. The possible role of pulmonary edema is discussed. Examination of these individuals 38 years later showed no physical changes believed to be related to their uranium exposure and no deposition of uranium could be detected. PMID:4067678

  1. Chemisorption of uranium hexa-fluoride on sodium fluoride pellets

    International Nuclear Information System (INIS)

    This paper comprises kinetics of chemical reaction or rather chemisorption of uranium hexafluoride gas on sodium fluoride pellets. The chemisorption is essentially irreversible at room temperature, while the process reverses at high temperature above 280 deg C. This chemisorption process was experimentally conducted in static condition at room temperature and its kinetics was studied. In the experiments, practically pure UF6 was used and the effects of gas pressure and weight of NaF pellets, were studied. In this heterogenous reaction, in which diffusion through ash layer is followed by chemical reaction, the reaction part is instantaneous and is first order with respect to gas concentration. Since the process of chemisorption is not only pure chemical reaction but also gas diffusion through ash layer, the rate constant depreciates with the percentage loading of UF6 on NaF pellets. The kinetic equation for the above process has been established for a particular size of NaF pellets and pellet porosity. (author)

  2. Uranium hexafluoride: A manual of good handling practices. Revision 7

    International Nuclear Information System (INIS)

    The United States Enrichment Corporation (USEC) is continuing the policy of the US Department of Energy (DOE) and its predecessor agencies in sharing with the nuclear industry their experience in the area of uranium hexafluoride (UF6) shipping containers and handling procedures. The USEC has reviewed Revision 6 or ORO-651 and is issuing this new edition to assure that the document includes the most recent information on UF6 handling procedures and reflects the policies of the USEC. This manual updates the material contained in earlier issues. It covers the essential aspects of UF6 handling, cylinder filling and emptying, general principles of weighing and sampling, shipping, and the use of protective overpacks. The physical and chemical properties of UF6 are also described. The procedures and systems described for safe handling of UF6 presented in this document have been developed and evaluated during more than 40 years of handling vast quantities of UF6. With proper consideration for its nuclear properties, UF6 may be safely handled in essentially the same manner as any other corrosive and/or toxic chemical

  3. Standard practice for bulk sampling of liquid uranium hexafluoride

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2001-01-01

    1.1 This practice covers methods for withdrawing representative samples of liquid uranium hexafluoride (UF6) from bulk quantities of the material. Such samples are used for determining compliance with the applicable commercial specification, for example Specification C787 and Specification C996. 1.2 It is assumed that the bulk liquid UF6 being sampled comprises a single quality and quantity of material. This practice does not address any special additional arrangements that might be required for taking proportional or composite samples, or when the sampled bulk material is being added to UF6 residues already in a container (“heels recycle”). 1.3 The number of samples to be taken, their nominal sample weight, and their disposition shall be agreed upon between the parties. 1.4 The scope of this practice does not include provisions for preventing criticality incidents. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of th...

  4. Development of 'MST-30' packaging for enriched uranium hexafluoride

    International Nuclear Information System (INIS)

    Revised IAEA Regulations for the Safe Transport of Radioactive Materials (ST-1) set forth incremental requirements for the transport of uranium hexafluoride (UF6. Of extreme importance is the new requirement (para. 677 (b)) that mandates the leak-tightness of the cylinder valve under accident conditions of transport. This new requirement is added from the point of view of the criticality safety of UF6. A new package, known as 'MST-30', of Type A Fissile material for enriched UF6, has been developed by Mitsubishi Materials Corporation to satisfy both new regulatory requirements and the present transport system. MST-30 reinforces the value protection function and utilises the high-density polyurethane foam as a shock absorbing media, instead of natural wood components. This paper (i) reviews the historical background that motivated the development, (ii) presents the design concept and features of the MST-30 package, and (iii) reports on the compliance test results that demonstrated the MST-30's superior ability to withstand accident conditions of transport. (author)

  5. Gas core reactors for actinide transmutation. [uranium hexafluoride

    Science.gov (United States)

    Clement, J. D.; Rust, J. H.; Wan, P. T.; Chow, S.

    1979-01-01

    The preliminary design of a uranium hexafluoride actinide transmutation reactor to convert long-lived actinide wastes to shorter-lived fission product wastes was analyzed. It is shown that externally moderated gas core reactors are ideal radiators. They provide an abundant supply of thermal neutrons and are insensitive to composition changes in the blanket. For the present reactor, an initial load of 6 metric tons of actinides is loaded. This is equivalent to the quantity produced by 300 LWR-years of operation. At the beginning, the core produces 2000 MWt while the blanket generates only 239 MWt. After four years of irradiation, the actinide mass is reduced to 3.9 metric tonnes. During this time, the blanket is becoming more fissile and its power rapidly approaches 1600 MWt. At the end of four years, continuous refueling of actinides is carried out and the actinide mass is held constant. Equilibrium is essentially achieved at the end of eight years. At equilibrium, the core is producing 1400 MWt and the blanket 1600 MWt. At this power level, the actinide destruction rate is equal to the production rate from 32 LWRs.

  6. Kinetics and mechanism of the reaction of uranium hexafluoride and tritium

    Science.gov (United States)

    Maienschein, Jon L.; Sunderland, William E.

    1985-03-01

    Using infrared analysis, we found that the reaction rate of gaseous uranium hexafluoride and tritium is determined solely by the rate at which energy from the radioactive decay of tritium is absorbed in the reaction mixture. Because uranium hexafluoride and tritium absorb β-energy with different efficiencies, the reaction rate is somewhat dependent on the initial reactant concentrations. Reaction products include uranium subfluorides and tritium fluoride. A radiochemistry model has been developed that includes β-energy production and absorption in the gas phase to allow calculation of the reaction yield per ion pair formed. With this model it was found that the reaction mechanism does not include lengthy chain propagation steps-only about 10 uranium hexafluoride molecules are consumed for each ion-pair formed in the gas phase. Many possible reaction steps are suggested that could contribute to the observed overall mechanism.

  7. Inductively coupled plasma-atomic emission spectroscopy: The determination of trace impurities in uranium hexafluoride

    Science.gov (United States)

    Floyd, M. A.; Morrow, R. W.; Farrar, R. B.

    An analytical method has been developed for the determination of trace impurities in high-purity uranium hexafluoride using liquid-liquid extraction of the uranium from the trace impurities followed by analysis with inductively coupled plasma-atomic emission spectroscopy. Detection limits, accuracy, and precision data are presented.

  8. Dry uranium tetrafluoride process preparation using the uranium hexafluoride reconversion process effluents

    International Nuclear Information System (INIS)

    It is a well known fact that the use of uranium tetrafluoride allows flexibility in the production of uranium suicide and uranium oxide fuel. To its obtention there are two conventional routes, the one which reduces uranium from the UF6 hydrolysis solution with stannous chloride, and the hydro fluorination of a solid uranium dioxide. In this work we are introducing a third and a dry way route, mainly utilized to the recovery of uranium from the liquid effluents generated in the uranium hexafluoride reconversion process, at IPEN/CNEN-SP. Working in the liquid phase, this route comprises the recuperation of ammonium fluoride by NH4HF2 precipitation. Working with the solid residues, the crystallized bifluoride is added to the solid UO2, which comes from the U mini plates recovery, also to its conversion in a solid state reaction, to obtain UF4. That returns to the process of metallic uranium production unity to the U3Si2 obtention. This fuel is considered in IPEN CNEN/SP as the high density fuel phase for IEA-R1m reactor, which will replace the former low density U3Si2-Al fuel. (author)

  9. Summary of the engineering analysis report for the long-term management of depleted uranium hexafluoride

    International Nuclear Information System (INIS)

    The Department of Energy (DOE) is reviewing ideas for the long-term management and use of its depleted uranium hexafluoride. DOE owns about 560,000 metric tons (over a billion pounds) of depleted uranium hexafluoride. This material is contained in steel cylinders located in storage yards near Paducah, Kentucky; Portsmouth, Ohio; and at the East Tennessee Technology Park (formerly the K-25 Site) in Oak Ridge, Tennessee. On November 10, 1994, DOE announced its new Depleted Uranium Hexafluoride Management Program by issuing a Request for Recommendations and an Advance Notice of Intent in the Federal Register (59 FR 56324 and 56325). The first part of this program consists of engineering, costs and environmental impact studies. Part one will conclude with the selection of a long-term management plan or strategy. Part two will carry out the selected strategy

  10. New approach for safeguarding enriched uranium hexafluoride bulk transfers

    International Nuclear Information System (INIS)

    The unique concepts of American National Standard ANSI N15.18-1975 ''Mass Calibration Techniques for Nuclear Material Control'' are discussed in regard to the establishment and maintenance of control of mass measurement of Uranium Hexafluoride (UF6) both within and between facilities. Emphasis is placed on the role of control of the measurements between facilities, and thus establish decision points for detection of measurement problems and making safeguards judgments. The unique concepts include the use of artifacts of UF6 packaging cylinders, calibrated by a central authority, to introduce the mass unit into all of the industries' weighing processes. These are called Replicate Mass Standards (RMS). This feat is accomplished by comparing the RMS to each facility's In-House Standards (IHS), also artifacts, and thence the usage of these IHS to quantify the systematic and random errors of each UF6 mass measurement process. A recent demonstration, which exchanged UF6 cylinders between two facilities, who used ANSI N15.18-1975 concepts and procedures is discussed. The discussion includes methodology and treatment of data for use in detection of measurement and safeguards problems. The discussion incorporates the methodology for data treatment and judgments concerning (1) the common base, (2) measurement process off-sets, (3) measurement process precision, and (4) shipper-receiver bulk measurement differences. From the evidence gained in the demonstration, conclusions are reached as to the usefulness of the realistic criteria for detection of mass measurement problems upon acceptance of the concepts of ANSI N15.18-1975

  11. Uranium hexafluoride: A manual of good handling practices

    International Nuclear Information System (INIS)

    For many years, the US Department of Energy (DOE) and its predecessor agencies have shared with the nuclear industry their experience in the area of uranium hexafluoride (UF6) shipping containers and handling procedures. The information contained in this manual updates information contained in earlier issues. It covers the essential aspects of UF6 handling, cylinder filling and emptying, general principles of weighing and sampling, shipping, and the use of protective overpacks. The physical and chemical properties of UF6 are also described and tabulated. The nuclear industry is responsible for furnishing its own shipping cylinders and suitable protective overpacks. A substantial effort has been made by the industry to standardize UF6 cylinders, samples, and overpacks. The quality of feed materials is important to the safe and efficient operation of the enriching facilities, and the UF6 product purity from the enriching facilities is equally important to the fuel fabricator, the utilities, the operators of research reactors, and other users. The requirements have been the impetus for an aggressive effort by DOE and its contractors to develop accurate techniques for sampling and for chemical and isotopic analysis. A quality control program is maintained within the DOE enriching facilities to ensure that the proper degree of accuracy and precision are obtained for all the required measurements. The procedures and systems described for safe handling of UF6 presented in this document have been developed and evaluated in DOE facilities during more than 40 years of handling vast quantities of UF6. With proper consideration for its nuclear properties, UF6 may be safely handled in essentially the same manner as any other corrosive and/or toxic chemical

  12. Ultrasonic thickness sampling plan for the depleted uranium hexafluoride program

    International Nuclear Information System (INIS)

    The United States Department of Energy (DOE) currently manages depleted uranium hexafluoride that is stored in approximately 50,000 carbon steel cylinders located at three DOE sites. The disposition of any particular cylinder for storage, handling, and transfer is based on the condition of the cylinder, where condition is ultimately reflected by the minimum wall thickness of a cylinder. Currently, the wall thickness of a cylinder may be measured using either a hand-held ultrasonic transducers or an automated scanner. At the Portsmouth site, the cylinder program is currently committed to a sampling plan that requires sampling 10% of the cylinders moved during the cylinder relocation efforts. The purpose of this report is to present a statistically-based sampling plan to be considered for use within the three site cylinder management program. This plan is designed to meet the following objectives: (1) allow determination of the current condition of the cylinder populations within the accuracy and confidence specified by cylinder program management, and (2) be sufficient for the models to be used for modeling purposes. The first objective does not require modeling in the sense of making assumptions about the corrosion process for the populations involved. By avoiding such additional assumptions, this may result in stronger statements to be made about the populations in question. Assumptions must be made regarding corrosion of the cylinders through time. The second objective depends on the particular model used. In this report, two basic methods are used in determining sample sizes. The sample sizes are intended to be conservative because it may be that other models are developed for use within the Program

  13. Uranium fluoride chemistry. Part 1. The gas phase reaction of uranium hexafluoride with alcohols

    International Nuclear Information System (INIS)

    The reaction between uranium hexafluoride (UF6) and simple alcohols in the gas phase was observed to proceed by way of three possible reaction pathways involving dehydration, deoxygenative fluorination, and ether formation. These reactions can best be explained by assuming that alcohols first react with UF6 to afford the alkoxy uranium pentafluoride intermediate ROUF5, which reacts further to give the dehydration, deoxygenative fluorination, and ether products. In each of the above three reaction pathways, UF6 is transformed to UOF4, which being as reactive toward alcohols as UF6, reacts further with the alcohol in question to finally afford the unreactive uranyl fluoride (UO2F2). 6 refs., 2 tabs

  14. Depleted Uranium Hexafluoride Management Program. The technology assessment report for the long-term management of depleted uranium hexafluoride. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Zoller, J.N.; Rosen, R.S.; Holliday, M.A. [and others

    1995-06-30

    With the publication of a Request for Recommendations and Advance Notice of Intent in the November 10, 1994 Federal Register, the Department of Energy initiated a program to assess alternative strategies for the long-term management or use of depleted uranium hexafluoride. This Request was made to help ensure that, by seeking as many recommendations as possible, Department management considers reasonable options in the long-range management strategy. The Depleted Uranium Hexafluoride Management Program consists of three major program elements: Engineering Analysis, Cost Analysis, and an Environmental Impact Statement. This Technology Assessment Report is the first part of the Engineering Analysis Project, and assesses recommendations from interested persons, industry, and Government agencies for potential uses for the depleted uranium hexafluoride stored at the gaseous diffusion plants in Paducah, Kentucky, and Portsmouth, Ohio, and at the Oak Ridge Reservation in Tennessee. Technologies that could facilitate the long-term management of this material are also assessed. The purpose of the Technology Assessment Report is to present the results of the evaluation of these recommendations. Department management will decide which recommendations will receive further study and evaluation.

  15. Depleted Uranium Hexafluoride Management Program. The technology assessment report for the long-term management of depleted uranium hexafluoride. Volume 1

    International Nuclear Information System (INIS)

    With the publication of a Request for Recommendations and Advance Notice of Intent in the November 10, 1994 Federal Register, the Department of Energy initiated a program to assess alternative strategies for the long-term management or use of depleted uranium hexafluoride. This Request was made to help ensure that, by seeking as many recommendations as possible, Department management considers reasonable options in the long-range management strategy. The Depleted Uranium Hexafluoride Management Program consists of three major program elements: Engineering Analysis, Cost Analysis, and an Environmental Impact Statement. This Technology Assessment Report is the first part of the Engineering Analysis Project, and assesses recommendations from interested persons, industry, and Government agencies for potential uses for the depleted uranium hexafluoride stored at the gaseous diffusion plants in Paducah, Kentucky, and Portsmouth, Ohio, and at the Oak Ridge Reservation in Tennessee. Technologies that could facilitate the long-term management of this material are also assessed. The purpose of the Technology Assessment Report is to present the results of the evaluation of these recommendations. Department management will decide which recommendations will receive further study and evaluation. These Appendices contain the Federal Register Notice, comments on evaluation factors, independent technical reviewers resumes, independent technical reviewers manual, and technology information packages

  16. Depleted Uranium Hexafluoride Management Program. The technology assessment report for the long-term management of depleted uranium hexafluoride. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Zoller, J.N.; Rosen, R.S.; Holliday, M.A. [and others

    1995-06-30

    With the publication of a Request for Recommendations and Advance Notice of Intent in the November 10, 1994 Federal Register, the Department of Energy initiated a program to assess alternative strategies for the long-term management or use of depleted uranium hexafluoride. This Request was made to help ensure that, by seeking as many recommendations as possible, Department management considers reasonable options in the long-range management strategy. The Depleted Uranium Hexafluoride Management Program consists of three major program elements: Engineering Analysis, Cost Analysis, and an Environmental Impact Statement. This Technology Assessment Report is the first part of the Engineering Analysis Project, and assesses recommendations from interested persons, industry, and Government agencies for potential uses for the depleted uranium hexafluoride stored at the gaseous diffusion plants in Paducah, Kentucky, and Portsmouth, Ohio, and at the Oak Ridge Reservation in Tennessee. Technologies that could facilitate the long-term management of this material are also assessed. The purpose of the Technology Assessment Report is to present the results of the evaluation of these recommendations. Department management will decide which recommendations will receive further study and evaluation. These Appendices contain the Federal Register Notice, comments on evaluation factors, independent technical reviewers resumes, independent technical reviewers manual, and technology information packages.

  17. Depleted Uranium Hexafluoride Management Program. The technology assessment report for the long-term management of depleted uranium hexafluoride. Volume 2

    International Nuclear Information System (INIS)

    With the publication of a Request for Recommendations and Advance Notice of Intent in the November 10, 1994 Federal Register, the Department of Energy initiated a program to assess alternative strategies for the long-term management or use of depleted uranium hexafluoride. This Request was made to help ensure that, by seeking as many recommendations as possible, Department management considers reasonable options in the long-range management strategy. The Depleted Uranium Hexafluoride Management Program consists of three major program elements: Engineering Analysis, Cost Analysis, and an Environmental Impact Statement. This Technology Assessment Report is the first part of the Engineering Analysis Project, and assesses recommendations from interested persons, industry, and Government agencies for potential uses for the depleted uranium hexafluoride stored at the gaseous diffusion plants in Paducah, Kentucky, and Portsmouth, Ohio, and at the Oak Ridge Reservation in Tennessee. Technologies that could facilitate the long-term management of this material are also assessed. The purpose of the Technology Assessment Report is to present the results of the evaluation of these recommendations. Department management will decide which recommendations will receive further study and evaluation

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

    International Nuclear Information System (INIS)

    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)

  19. Pattern of explosive reaction between uranium hexafluoride and hydrocarbon oils. Revision 1

    International Nuclear Information System (INIS)

    Examination of uranium hexafluoride release incidents occurring over the past three decades of ORGDP experience has identified only four which apparently involved an explosion of a container resulting from reaction between uranium hexafluoride and an impurity. These four incidents exhibit a certain degree of commonality. Each has involved: (1) condensed phase uranium hexafluoride, (2) a moderately elevated temperature, (3) a sufficient quantity of uranium hexafluoride for a significant partial pressure to be maintained independently above that which can be consumed by chemical reaction, and (4) an organic liquid (probably hydrocarbon oil) accidentally present in the container as a contaminant. The purpose of this investigative search was to establish some conditional pattern for these four incidents to which their violent consequences could be attributed. Fortunately, the number of such incidents is relatively small, which emphasizes even more pointedly the unfortunate fact that documentation ranges from thorough to very limited. Documented sources of information are given in the bibliography. Copies of those which are not readily available are contained in six appendices. 8 refs

  20. 49 CFR 173.420 - Uranium hexafluoride (fissile, fissile excepted and non-fissile).

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Uranium hexafluoride (fissile, fissile excepted and non-fissile). 173.420 Section 173.420 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS SHIPPERS-GENERAL REQUIREMENTS...

  1. On the infrared-active overtones n nu 3 of uranium hexafluoride

    Science.gov (United States)

    van der Merwe, P. du T.

    1993-10-01

    A perspective is provided of the infrared-active fundamental mode ν3 and the band structure of its overtones relevant for uranium hexafluoride. The treatment is based on nonlinear (Morse-type) creation and annihilation operators. The spectrum generating algebra provides ready access to anharmonic spectral features which incorporate dissociation characteristics.

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

    International Nuclear Information System (INIS)

    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.)

  3. Depleted uranium hexafluoride management program : data compilation for the Paducah site

    International Nuclear Information System (INIS)

    This report is a compilation of data and analyses for the Paducah site, near Paducah, Kentucky. The data were collected and the analyses were done in support of the U.S. Department of Energy (DOE) 1999 Programmatic Environmental Impact Statement for Alternative Strategies for the Long-Term Management and Use of Depleted Uranium Hexafluoride (DOE/EIS-0269). The report describes the affected environment at the Paducah site and summarizes potential environmental impacts that could result from conducting the following depleted uranium hexafluoride (UF6) activities at the site: continued cylinder storage, preparation of cylinders for shipment, conversion, and long-term storage. DOE's preferred alternative is to begin converting the depleted UF6 inventory as soon as possible to either uranium oxide, uranium metal, or a combination of both, while allowing for use of as much of this inventory as possible

  4. Standard test methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of uranium hexafluoride

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 These test methods cover procedures for subsampling and for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of uranium hexafluoride UF6. Most of these test methods are in routine use to determine conformance to UF6 specifications in the Enrichment and Conversion Facilities. 1.2 The analytical procedures in this document appear in the following order: Note 1—Subcommittee C26.05 will confer with C26.02 concerning the renumbered section in Test Methods C761 to determine how concerns with renumbering these sections, as analytical methods are replaced with stand-alone analytical methods, are best addressed in subsequent publications. Sections Subsampling of Uranium Hexafluoride 7 - 10 Gravimetric Determination of Uranium 11 - 19 Titrimetric Determination of Uranium 20 Preparation of High-Purity U3O 8 21 Isotopic Analysis 22 Isotopic Analysis by Double-Standard Mass-Spectrometer Method 23 - 29 Determination of Hydrocarbons, Chlorocarbons, and Partially Substitut...

  5. Engineering analysis report for the long-term management of depleted uranium hexafluoride : storage of depleted uranium metal

    International Nuclear Information System (INIS)

    This report contains an engineering analysis of long-term storage of uranium metal in boxes as an option for long-term management of depleted uranium hexafluoride (UF6). Three storage facilities are considered: buildings, vaults, and mined cavities. Three cases are considered: either all, half, or a quarter of the depleted uranium metal that would be produced from the conversion of depleted UF6 is stored at the facility. The analysis of these alternatives is based on a box design used in the Final Programmatic Environmental Impact Statement for Alternative Strategies for the Long-Term Management and Use of Depleted Uranium Hexafluoride, report DOE/EIS-0269, published in 1999 by the US Department of Energy. This box design does not appear to effectively use space within the box. Hence, an alternative box design that allows for a reduced storage area is addressed in the appendices for long-term storage in buildings

  6. US Transuranium and Uranium Registries case study on accidental exposure to uranium hexafluoride

    International Nuclear Information System (INIS)

    The United States Transuranium and Uranium Registries’ (USTUR) whole-body donor (Case 1031) was exposed to an acute inhalation of uranium hexafluoride (UF6) produced from an explosion at a uranium processing plant 65 years prior to his death. The USTUR measurements of tissue samples collected at the autopsy indicated long-term retention of inhaled slightly enriched uranium material (0.85% 235U) in the deep lungs and thoracic lymph nodes. In the present study, the authors combined the tissue measurement results with historical bioassay data, and analysed them with International Commission on Radiological Protection (ICRP) respiratory tract models and the ICRP Publication 69 systemic model for uranium using maximum likelihood and Bayesian statistical methods. The purpose of the analysis was to estimate intakes and model parameter values that best describe the data, and evaluate their effect on dose assessment. The maximum likelihood analysis, which used the ICRP Publication 66 human respiratory tract model, resulted in a point estimate of 79 mg of uranium for the occupational intake composed of 86% soluble, type F material and 14% insoluble, type S material. For the Bayesian approach, the authors applied the Markov Chain Monte Carlo method, but this time used the revised human respiratory tract model, which is currently being used by ICRP to calculate new dose coefficients for workers. The Bayesian analysis estimated that the mean uranium intake was 160 mg, and calculated the case-specific lung dissolution parameters with their associated uncertainties. The parameters were consistent with the inhaled uranium material being predominantly soluble with a small but significant insoluble component. The 95% posterior range of the rapid dissolution fraction (the fraction of deposited material that is absorbed to blood rapidly) was 0.12 to 0.91 with a median of 0.37. The remaining fraction was absorbed slowly, with a 95% range of 0.000 22 d−1 to 0.000 36

  7. US Transuranium and Uranium Registries case study on accidental exposure to uranium hexafluoride.

    Science.gov (United States)

    Avtandilashvili, Maia; Puncher, Matthew; McComish, Stacey L; Tolmachev, Sergei Y

    2015-03-01

    The United States Transuranium and Uranium Registries' (USTUR) whole-body donor (Case 1031) was exposed to an acute inhalation of uranium hexafluoride (UF6) produced from an explosion at a uranium processing plant 65 years prior to his death. The USTUR measurements of tissue samples collected at the autopsy indicated long-term retention of inhaled slightly enriched uranium material (0.85% (235)U) in the deep lungs and thoracic lymph nodes. In the present study, the authors combined the tissue measurement results with historical bioassay data, and analysed them with International Commission on Radiological Protection (ICRP) respiratory tract models and the ICRP Publication 69 systemic model for uranium using maximum likelihood and Bayesian statistical methods. The purpose of the analysis was to estimate intakes and model parameter values that best describe the data, and evaluate their effect on dose assessment. The maximum likelihood analysis, which used the ICRP Publication 66 human respiratory tract model, resulted in a point estimate of 79 mg of uranium for the occupational intake composed of 86% soluble, type F material and 14% insoluble, type S material. For the Bayesian approach, the authors applied the Markov Chain Monte Carlo method, but this time used the revised human respiratory tract model, which is currently being used by ICRP to calculate new dose coefficients for workers. The Bayesian analysis estimated that the mean uranium intake was 160 mg, and calculated the case-specific lung dissolution parameters with their associated uncertainties. The parameters were consistent with the inhaled uranium material being predominantly soluble with a small but significant insoluble component. The 95% posterior range of the rapid dissolution fraction (the fraction of deposited material that is absorbed to blood rapidly) was 0.12 to 0.91 with a median of 0.37. The remaining fraction was absorbed slowly, with a 95% range of 0.000 22 d(-1) to 0.000 36

  8. Cost estimate report for the long-term management of depleted uranium hexafluoride : storage of depleted uranium metal

    International Nuclear Information System (INIS)

    This report contains a cost analysis of the long-term storage of depleted uranium in the form of uranium metal. Three options are considered for storage of the depleted uranium. These options are aboveground buildings, partly underground vaults, and mined cavities. Three cases are presented. In the first case, all the depleted uranium metal that would be produced from the conversion of depleted uranium hexafluoride (UF6) generated by the US Department of Energy (DOE) prior to July 1993 would be stored at the storage facility (100% Case). In the second case, half the depleted uranium metal would be stored at this storage facility (50% Case). In the third case, one-quarter of the depleted uranium metal would be stored at the storage facility (25% Case). The technical basis for the cost analysis presented in this report is principally found in the companion report, ANL/EAD/TM-100, ''Engineering Analysis Report for the Long-Term Management of Depleted Uranium Hexafluoride: Storage of Depleted Uranium Metal'', prepared by Argonne National Laboratory

  9. Cost update technology, safety, and costs of decommissioning a reference uranium hexafluoride conversion plant

    International Nuclear Information System (INIS)

    The purpose of this study is to update the cost estimates developed in a previous report, NUREG/CR-1757 (Elder 1980) for decommissioning a reference uranium hexafluoride conversion plant from the original mid-1981 dollars to values representative of January 1993. The cost updates were performed by using escalation factors derived from cost index trends over the past 11.5 years. Contemporary price quotes wee used for costs that have increased drastically or for which is is difficult to find a cost trend. No changes were made in the decommissioning procedures or cost element requirements assumed in NUREG/CR-1757. This report includes only information that was changed from NUREG/CR-1757. Thus, for those interested in detailed descriptions and associated information for the reference uranium hexafluoride conversion plant, a copy of NUREG/CR-1757 will be needed

  10. Process for cleaning adhering or dust deposits in plants for handling uranium hexafluoride

    International Nuclear Information System (INIS)

    Deposits are removed by the reaction with iodine heptafluoride, where trifluor bromium methane or difluor bromium methane is also added. Bromium trifluoride is formed in the plant, which converts uranyl fluoride into uranium hexafluoride. The bromium produced is immediately fluorized by excess iodine hepta fluoride or fluorine. The corrosion effect of the bromine is prevented in this way. The bromium trifluoride is present in liquid form and can completely wet the plant walls. (PW)

  11. Certification of the uranium hexafluoride (UF6) isotopic composition: The IRMM-019 to IRMM-029 series

    OpenAIRE

    MIALLE SÉBASTIEN; Richter, Stephan; TRUYENS Jan; HENNESSY Carmel; Jakobsson, Ulf; Aregbe, Yetunde

    2014-01-01

    This report describes the re-determination and certification of the IRMM-019 to IRMM-029 series of uranium hexafluoride (UF6) reference materials certified for the uranium isotopic composition. The values were assigned following ISO Guide 34:2009. The IRMM-019 to IRMM-029 series was originally produced and certified in the 1980's-1990's. Since, the materials are stored in monel ampoules. Upon customer request, UF6 gas is distilled from a mother ampoule into a daughter ampoule, the isotopic...

  12. Standards for uranium hexafluoride (UF6) mass spectrometry

    OpenAIRE

    Richter, Stephan; Kühn, H.; TRUYENS Jan; MIALLE SÉBASTIEN; Aregbe, Yetunde

    2013-01-01

    For UF6 mass spectrometry two types of "standards" are equally important: firstly "documentary standards" which describe specific measurement techniques and associated calculations, and secondly "material standards" which are preferentially SItraceable certified isotopic reference materials, as e.g. provided by the European Commission's Institute for Reference Materials and Measurements (IRMM). Recently the IRMM has upgraded its facilities for uranium isotopic measurements using uranium he...

  13. Geological conditions of safe long-term storage and disposal of depleted uranium hexafluoride

    Science.gov (United States)

    Laverov, N. P.; Velichkin, V. I.; Omel'Yanenko, B. I.; Yudintsev, S. V.; Tagirov, B. R.

    2010-08-01

    The production of enriched uranium used in nuclear weapons and fuel for atomic power plants is accompanied by the formation of depleted uranium (DU), the amount of which annually increases by 35-40 kt. To date, more than 1.6 Mt DU has accumulated in the world. The main DU mass is stored as environ-mentally hazardous uranium hexafluoride (UF6), which is highly volatile and soluble in water with the formation of hydrofluoric acid. To ensure safe UF6 storage, it is necessary to convert this compound in chemically stable phases. The industrial reprocessing of UF6 into U3O8 and HF implemented in France is highly expensive. We substantiate the expediency of long-term storage of depleted uranium hexafluoride in underground repositories localized in limestone. On the basis of geochemical data and thermodynamic calculations, we show that interaction in the steel container-UF6-limestone-groundwater system gives rise to the development of a slightly alkaline reductive medium favorable for chemical reaction with formation of uraninite (UO2) and fluorite (CaF2). The proposed engineering solution not only ensures safe DU storage but also makes it possible to produce uraninite, which can be utilized, if necessary, in fast-neutron reactors. In the course of further investigations aimed at safe maintenance of DU, it is necessary to study the kinetics of conversion of UF6 into stable phases, involving laboratory and field experiments.

  14. Evaluation of health effects in Sequoyah Fuels Corporation workers from accidental exposure to uranium hexafluoride

    International Nuclear Information System (INIS)

    Urine bioassay measurements for uranium and medical laboratory results were studied to determine whether there were any health effects from uranium intake among a group of 31 workers exposed to uranium hexafluoride (UF6) and hydrolysis products following the accidental rupture of a 14-ton shipping cylinder in early 1986 at the Sequoyah Fuels Corporation uranium conversion facility in Gore, Oklahoma. Physiological indicators studied to detect kidney tissue damage included tests for urinary protein, casts and cells, blood, specific gravity, and urine pH, blood urea nitrogen, and blood creatinine. We concluded after reviewing two years of follow-up medical data that none of the 31 workers sustained any observable health effects from exposure to uranium. The early excretion of uranium in urine showed more rapid systemic uptake of uranium from the lung than is assumed using the International Commission on Radiological Protection (ICRP) Publication 30 and Publication 54 models. The urinary excretion data from these workers were used to develop an improved systemic recycling model for inhaled soluble uranium. We estimated initial intakes, clearance rates, kidney burdens, and resulting radiation doses to lungs, kidneys, and bone surfaces. 38 refs., 10 figs., 7 tabs

  15. Modified sodium diuranate process for the recovery of uranium from uranium hexafluoride transport cylinder wash solution

    Science.gov (United States)

    Meredith, Austin Dean

    Uranium hexafluoride (UF6) containment cylinders must be emptied and washed every five years in order to undergo recertification, according to ANSI standards. During the emptying of the UF6 from the cylinders, a thin residue, or heel, of UF6 is left behind. This heel must be removed in order for recertification to take place. To remove it, the inside of the containment cylinder is washed with acid and the resulting solution generally contains three or four kilograms of uranium. Thus, before the liquid solution can be disposed of, the uranium must be separated. A modified sodium diuranate (SDU) uranium recovery process was studied to support development of a commercial process. This process was sought to ensure complete uranium recovery, at high purity, in order that it might be reused in the nuclear fuel cycle. An experimental procedure was designed and carried out in order to verify the effectiveness of the commercial process in a laboratory setting. The experiments involved a small quantity of dried UO2F2 powder that was dosed with 3wt% FeF3 and was dissolved in water to simulate the cylinder wash solution. Each experiment series started with a measured amount of this powder mixture which was dissolved in enough water to make a solution containing about 120 gmU/liter. The experiments involved validating the modified SDU extraction process. A potassium diuranate (KDU) process was also attempted. Very little information exists regarding such a process, so the task was undertaken to evaluate its efficacy and determine whether a potassium process yields any significant differences or advantages as compared to a sodium process. However, the KDU process ultimately proved ineffective and was abandoned. Each of the experiments was organized into a series of procedures that started with the UO2F2 powder being dissolved in water, and proceeded through the steps needed to first convert the uranium to a diuranate precipitate, then to a carbonate complex solution, and finally

  16. Radiation protection training at uranium hexafluoride and fuel fabrication plants

    International Nuclear Information System (INIS)

    This report provides general information and references useful for establishing or operating radiation safety training programs in plants that manufacture nuclear fuels, or process uranium compounds that are used in the manufacture of nuclear fuels. In addition to a brief summary of the principles of effective management of radiation safety training, the report also contains an appendix that provides a comprehensive checklist of scientific, safety, and management topics, from which appropriate topics may be selected in preparing training outlines for various job categories or tasks pertaining to the uranium nuclear fuels industry. The report is designed for use by radiation safety training professionals who have the experience to utilize the report to not only select the appropriate topics, but also to tailor the specific details and depth of coverage of each training session to match both employee and management needs of a particular industrial operation. 26 refs., 3 tabs

  17. Containment and storage of uranium hexafluoride at US Department of Energy uranium enrichment plants

    International Nuclear Information System (INIS)

    Isotopically depleted UF6 (uranium hexafluoride) accumulates at a rate five to ten times greater than the enriched product and is stored in steel vessels at the enrichment plant sites. There are approximately 55,000 large cylinders now in storage at Paducah, Kentucky; Portsmouth, Ohio; and Oak Ridge, Tennessee. Most of them contain a nominal 14 tons of depleted UF6. Some of these cylinders have been in the unprotected outdoor storage environment for periods approaching 40 years. Storage experience, supplemented by limited corrosion data, suggests a service life of about 70 years under optimum conditions for the 48-in. diameter, 5/16-in.-wall pressure vessels (100 psi working pressure), using a conservative industry-established 1/4-in.-wall thickness as the service limit. In the past few years, however, factors other than atmospheric corrosion have become apparent that adversely affect the serviceability of small numbers of the storage containers and that indicate the need for a managed program to ensure maintenance ofcontainment integrity for all the cylinders in storage. The program includes periodic visual inspections of cylinders and storage yards with documentation for comparison with other inspections, a group of corrosion test programs to permit cylinder life forecasts, and identification of (and scheduling for remedial action) situations in which defects, due to handling damage or accelerated corrosion, can seriously shorten the storage life or compromise the containment integrity of individual cylinders. The program also includes rupture testing to assess the effects of certain classes of damage on overall cylinder strength, aswell as ongoing reviews of specifications, procedures, practices, and inspection results to effect improvements in handling safety, containment integrity, and storage life

  18. Determination of trace impurities in uranium hexafluoride using inductively coupled plasma-atomic emission spectroscopy

    International Nuclear Information System (INIS)

    A procedure has been developed to determine 30 trace elements in high-purity uranium hexafluoride (UF6) using inductively coupled plasma-atomic emission spectroscopy. The analytical method consists of a liquid-liquid extraction of the uranium from the trace impurities with a tri-(2-ethyl-hexyl)-phosphate (TEHP)-hexane mixture. A computer-controlled scanning monochromator system interfaced to an inductively coupled plasma (ICP) is then used to determine the levels of 30 trace elements present in the UF6. A single sample dissolution procedure is used for all elements investigated. This preliminary report details experimental work done to date as part of a countinuing program to determine metallic impurities in uranium by ICP

  19. Evaluation of a quadrupole mass spectrometer for the isotopic analysis of uranium hexafluoride

    International Nuclear Information System (INIS)

    A quadrupole mass spectrometer was examined for adaptation to the on-stream isotopic analysis of uranium hexafluoride (UF6) in gaseous diffusion cascades. Source modifications, in conjunction with a molecular beam type inlet system and a liquid nitrogen cold trap, made the quadrupole reasonably compatible with UF6 at analyzer pressures of not more than 10-8 torr. Uranium-235/uranium-238 ratios were measured using automatic peak-switching and integrating circuitry. These measurements indicated that the apparent high resolution of the quadrupole could not be realized with UF6, due to inadequate sensitivity and low signal-to-noise ratio. After extensive examination of the system, it was concluded that further efforts to adapt the quadrupole to isotopic analysis of UF6 would be impractical at this stage in quadrupole development. (U.S.)

  20. Optical methods for research of uranium hexafluoride under conditions imitating the atmosphere

    Science.gov (United States)

    Gerin, I. I.; Penin, S. T.; Chistyakova, L. K.

    2006-02-01

    Capabilities of optical methods in real-time monitoring of uranium hexafluoride and products of its hydrolysis in the air over the production areas have been studied experimentally in the process of hydrolysis of uranium hexafluoride under controlled conditions imitating the atmosphere. The scattering and absorption coefficients were used to study the process of formation and kinetics of aerosols at interaction of UF 6 with water vapor. It has been shown that time of aerosol formation is mostly determined by time of the hydrolysis, and the lifetime of aerosols is determined by diffusion and convective processes, as well as coagulation. At low concentrations of the parent material the effect of coagulation on the process of aerosol formation is insignificant because of low collision probability of particles. When initial concentration of UF 6 (up to 20 g×m -3) increases hydrolysis occurs faster, and particles are generated during minutes and less. At tenfold excess over the H II0, concentration the intense (active) volume hydrolysis of uranium hexafluoride occurs with formation of aerosols even at the low concentration of UF 6, and this hydrolysis terminates within first 20 min. At lower concentrations of initial substances (~25 μg×m -3), the process of intense hydrolysis proceeds slower and generation of aerosol has no pronounced time interval. It should be emphasized that termination of the intense hydrolysis does not mean complete termination of the reaction that indicate presence of a "penetrative fraction" of UF 6, which continues to react with H II0 and hydrolysis products more than hour. The experiments showed that optical methods allow rather reliable detection of low concentrations of radioactive and toxic admixtures at UF 6 hydrolysis at the level exceeding the MPC, and the equipment based on these methods is capable of providing the reliable monitoring of pre-emergency situations; in addition, this equipment is relatively cheap and convenient in use.

  1. Chemical toxicity of uranium hexafluoride compared to acute effects of radiation

    International Nuclear Information System (INIS)

    The chemical effects from acute exposures to uranium hexafluoride are compared to the nonstochastic effects from acute radiation doses of 25 rems to the whole body and 300 rems to the thyroid. The analysis concludes that an intake of about 10 mg of uranium in soluble form is roughly comparable, in terms of early effects, to an acute whole body dose of 25 rems because both are just below the threshold for significant nonstochastic effects. Similarly, an exposure to hydrogen fluoride at a concentration of 25 mg/m3 for 30 minutes is roughly comparable because there would be no significant nonstochastic effects. For times t other than 30 minutes, the concentration C of hydrogen fluoride considered to have the same effect can be calculated using a quadratic equation: C = 25 mg/m3 (30 min/t). The purpose of these analyses is to provide information for developing design and siting guideline based on chemical toxicity for enrichment plants using uranium hexafluoride. These guidelines are to be similar, in terms of stochastic health effects, to criteria in NRC regulations of nuclear power plants, which are based on radiation doses. 26 refs., 1 fig., 5 tabs

  2. Behaviour of natural uranium hexafluoride containers in the case of a fire

    International Nuclear Information System (INIS)

    The new international regulations on the safety of radioactive materials transports suggested by the IAEA require the fire resistance of containers used for uranium hexafluoride (UF6) transport. Containers have to resist to an enveloping flame of 800 degrees Celsius between 30 minutes. These measures have been decided after accidents have occurred and take into account the UF6 chemical derivatives toxicity. As part of the international research program ''Tenerife'', several experiments have been carried out to study the fire resistance of big UF6 containers. The technical characteristics and the first experimental results of these tests are described. (O.M.)

  3. Standard test method for determination of technetium-99 in uranium hexafluoride by liquid scintillation counting

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This test method is a quantitative method used to determine technetium-99 (99Tc) in uranium hexafluoride (UF6) by liquid scintillation counting. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  4. Standard guide for determination of plutonium and neptunium in uranium hexafluoride by alpha spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This method covers the determination of plutonium and neptunium isotopes in uranium hexafluoride by alpha spectroscopy. The method can also be applicable to any matrix that may be converted to a nitric acid system. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory requirements prior to use.

  5. The action of uranium hexafluoride on some metallic fluorides (1962)

    International Nuclear Information System (INIS)

    A metallic difluoride is inert to UF6 unless the metal can exist in a higher valency state. In this case, UF6 acts as an oxidising agent and is transformed into UF4. The fluorides of tri- and tetra-valent metals give rise to new compounds when they are maintained at a high temperature (500 deg. C) in the presence of uranium hexachloride vapour. The products obtained are characterized by their X-ray diffraction diagrams. The distributions of the lines of the powder diagrams are very similar to that of U4F17. Assuming that this resemblance is due to a stacking of identical fluorine atoms, it can be calculated that the corresponding structure is given by the theoretical formulae: MeF3, 0,562 UF6; MeF4, 0,396 UF6 which are in good agreement with chemical measurements. (author)

  6. Influence of temperature and pressure in adsorption of uranium hexafluoride on carbon nano tube by Monte Carlo simulation study

    International Nuclear Information System (INIS)

    Uranium hexafluoride physical adsorption on armchair carbon nano tubes is studied with Monte Carlo Simulations in a wide range of temperatures and pressures. All of the particle particle interaction are modeled with Lennard-Jones potential. We have written a FORTRAN program for Monte Carlo simulation and then calculated the inside density of carbon nano tube, out side density of carbon nano tube and total density of carbon nano tube. The conclusions drown from theses calculations are then contrasted and compared. Result show that the total amount of uranium hexafluoride adsorption on single-walled carbon nano tube, increases with high pressure and low temperature

  7. Standard specification for uranium hexafluoride enriched to less than 5 % 235U

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This specification covers nuclear grade uranium hexafluoride (UF6) that either has been processed through an enrichment plant, or has been produced by the blending of Highly Enriched Uranium with other uranium to obtain uranium of any 235U concentration below 5 % and that is intended for fuel fabrication. The objectives of this specification are twofold: (1) To define the impurity and uranium isotope limits for Enriched Commercial Grade UF6 so that, with respect to fuel design and manufacture, it is essentially equivalent to enriched uranium made from natural UF6; and (2) To define limits for Enriched Reprocessed UF6 to be expected if Reprocessed UF6 is to be enriched without dilution with Commercial Natural UF6. For such UF6, special provisions, not defined herein, may be needed to ensure fuel performance and to protect the work force, process equipment, and the environment. 1.2 This specification is intended to provide the nuclear industry with a standard for enriched UF6 that is to be used in the pro...

  8. Circulation system for flowing uranium hexafluoride cavity reactor experiments

    Science.gov (United States)

    Jaminet, J. F.; Kendall, J. S.

    1976-01-01

    Research related to determining the feasibility of producing continuous power from fissile fuel in the gaseous state is presented. The development of three laboratory-scale flow systems for handling gaseous UF6 at temperatures up to 500 K, pressure up to approximately 40 atm, and continuous flow rates up to approximately 50g/s is presented. A UF6 handling system fabricated for static critical tests currently being conducted is described. The system was designed to supply UF6 to a double-walled aluminum core canister assembly at temperatures between 300 K and 400 K and pressure up to 4 atm. A second UF6 handling system designed to provide a circulating flow of up to 50g/s of gaseous UF6 in a closed-loop through a double-walled aluminum core canister with controlled temperature and pressure is described. Data from flow tests using UF6 and UF6/He mixtures with this system at flow rates up to approximately 12g/s and pressure up to 4 atm are presented. A third UF6 handling system fabricated to provide a continuous flow of UF6 at flow rates up to 5g/s and at pressures up to 40 atm for use in rf-heated, uranium plasma confinement experiments is described.

  9. Some parameters of uranium hexafluoride plasma produced by products of nuclear reaction

    International Nuclear Information System (INIS)

    The probe experimental results of investigation of uranium hexafluoride plasma produced in the centre of nuclear reactor core were demonstrated. Study of uranium hexafluoride plasma is continued by the following reasons: a possibility of U F6 utilization as nuclear fuel, the utilization of U F6 as volume source o ionization, search of active laser media compatible with U F6 that is complicated by lack of constant rates data for most of plasma-chemical reactions with U F6 and his dissociation products. Cylindrical probe volt-ampere characteristics (VAC) measured in U F6 plasma at pressure 20 Torr and different thermal neutron fluxes and have following features: -firstly, it is possible to choose a linear part in the field of small positive potentials of probe (0-1) V; - secondary, ion branches of VAC have typical break which current of satiation corresponds to; -thirdly, probe VAC measured at small values of thermal neutron flux density are symmetrical. Diagnostics approaches were used for interpretation VAC of probe. The values of satiation current and linear part of electron branch were calculated, and such plasma parameters as conductivity, diffusion coefficient values of positive and negative ions were determined. The resonance recharge cross section was estimated on diffusion coefficient value

  10. Alpha particle induced gamma yields in uranium hexafluoride

    Science.gov (United States)

    Croft, Stephen; Swinhoe, Martyn T.; Miller, Karen A.

    2013-01-01

    Fluorine has a relatively large (α,n) production cross-section in the MeV range, the energy range of interest for special nuclear materials. In the uranium fuel cycle enriched UF6 in particular is a reasonably prolific source of (α,n) neutrons because along with 235U, 234U becomes enriched and it has a relatively short half-life. This enables the mass content of storage cylinders containing UF6 to be verified by neutron counting methods. In association with such measurements high resolution gamma-ray spectrometry (HRGS) measurements using a high-purity Ge detector are often undertaken to determine the 235U enrichment based off the intensity of the direct 186 keV line. The specific (α,n) neutron production, neutrons per second per gram of U, is sensitive to the relative isotopic composition, particularly the 234U concentration, and the traditional gross neutron counting approach is needed to quantitatively interpret the data. In addition to F(α,n) neutrons, α-induced reaction γ-rays are generated, notably at 110, 197, 582, 891, 1236 and 1275 keV. If one could observe 19F(α,xγ) gamma-lines in the HRGS spectra the thought was that perhaps the α-activity could be estimated directly, and in turn the 234U abundance obtained. For example, by utilizing the ratio of the detected 197-186 keV full energy peaks. However, until now there has been no readily available estimate of the expected strength of the reaction gamma-rays nor any serious consideration as to whether they might be diagnostic or not. In this work we compute the thick target yields of the chief reaction gamma-rays in UF6 using published thin target data. Comparisons are made to the neutron production rates to obtain γ/n estimates, and also to the 235U decay line at 186 keV which we take as a fiducial line. It is shown that the reaction gamma-rays are produced but are far too weak for practical safeguards purposes. Now that the underlying numerical data is readily available however, it can be used to

  11. Conversion and Blending Facility Highly enriched uranium to low enriched uranium as uranium hexafluoride. Revision 1

    International Nuclear Information System (INIS)

    This report describes the Conversion and Blending Facility (CBF) which will have two missions: (1) convert surplus HEU materials to pure HEU UF6 and a (2) blend the pure HEU UF6 with diluent UF6 to produce LWR grade LEU-UF6. The primary emphasis of this blending be to destroy the weapons capability of large, surplus stockpiles of HEU. The blended LEU product can only be made weapons capable again by the uranium enrichment process. The chemical and isotopic concentrations of the blended LEU product will be held within the specifications required for LWR fuel. The blended LEU product will be offered to the United States Enrichment Corporation (USEC) to be sold as feed material to the commercial nuclear industry

  12. CO-laser induced photochemical reaction of UF6 with HCl for the isotope separation of uranium hexafluoride

    International Nuclear Information System (INIS)

    In this paper, the authors report the results of CO-laser induced photochemical reaction of UF6 with HCl for the isotope separation of uranium hexafluoride, they also discussed that the molecular collision inducing V-T, V-V relaxation process affects on the selectivity of the isotope separation. The obtained quantum coefficiency of the reaction is about 0.34

  13. CO-laser-induced photochemical reaction of UF6 with HCl for the isotope separation of uranium hexafluoride

    Science.gov (United States)

    Ding, Hong-Bin; Shen, Z. Y.; Zhang, Cun H.

    1993-05-01

    In this paper, we report the results of CO-laser induced photochemical reaction of UF6 with HCl for the isotope separation of uranium hexafluoride, we also discussed that the molecular collision inducing V-T, V-V relaxation process affects on the selectivity of the isotope separation. The obtained quantum coefficiency of the reaction is about 0.34.

  14. TRANSITION STATE FOR THE GAS-PHASE REACTION OF URANIUM HEXAFLUORIDE WITH WATER

    Energy Technology Data Exchange (ETDEWEB)

    Garrison, S; James Becnel, J

    2008-03-18

    Density Functional Theory and small-core, relativistic pseudopotentials were used to look for symmetric and asymmetric transitions states of the gas-phase hydrolysis reaction of uranium hexafluoride, UF{sub 6}, with water. At the B3LYP/6-31G(d,p)/SDD level, an asymmetric transition state leading to the formation of a uranium hydroxyl fluoride, U(OH)F{sub 5}, and hydrogen fluoride was found with an energy barrier of +77.3 kJ/mol and an enthalpy of reaction of +63.0 kJ/mol (both including zero-point energy corrections). Addition of diffuse functions to all atoms except uranium led to only minor changes in the structure and relative energies of the reacting complex and transition state. However, a significant change in the product complex structure was found, significantly reducing the enthalpy of reaction to +31.9 kJ/mol. Similar structures and values were found for PBE0 and MP2 calculations with this larger basis set, supporting the B3LYP results. No symmetric transition state leading to the direct formation of uranium oxide tetrafluoride, UOF{sub 4}, was found, indicating that the reaction under ambient conditions likely includes several more steps than the mechanisms commonly mentioned. The transition state presented here appears to be the first published transition state for the important gas-phase reaction of UF{sub 6} with water.

  15. Transition state for the gas-phase reaction of uranium hexafluoride with water.

    Science.gov (United States)

    Garrison, Stephen L; Becnel, James M

    2008-06-19

    Density functional theory and small-core, relativistic pseudopotentials were used to look for symmetric and asymmetric transition states of the gas-phase hydrolysis reaction of uranium hexafluoride, UF 6, with water. At the B3LYP/6-31G(d,p)/SDD level, an asymmetric transition state leading to the formation of a uranium hydroxyl fluoride, U(OH)F 5, and hydrogen fluoride was found with an energy barrier of +77.3 kJ/mol and an enthalpy of reaction of +63.0 kJ/mol (both including zero-point energy corrections). Addition of diffuse functions to all atoms except uranium led to only minor changes in the structures and relative energies of the reacting complex and transition state. However, a significant change in the structure of the product complex was found, significantly reducing the enthalpy of reaction to +31.9 kJ/mol. Similar structures and values were found for PBE0 and MP2 calculations with this larger basis set, supporting the B3LYP results. No symmetric transition state leading to the direct formation of uranium oxide tetrafluoride, UOF 4, was found, indicating that the reaction under ambient conditions likely includes several more steps than the mechanisms commonly mentioned. The transition state presented here appears to be the first published transition state for the important gas-phase reaction of UF 6 with water. PMID:18500792

  16. A concept of a nonfissile uranium hexafluoride overpack for storage, transport, and processing of corroded cylinders

    International Nuclear Information System (INIS)

    There is a need to develop a means of safely transporting breached 48-in. cylinders containing depleted uranium hexafluoride (UF6) from current storage locations to locations where the contents can be safely removed. There is also a need to provide a method of safely and easily transporting degraded cylinders that no longer meet the US Department of Transportation (DOT) and American National Standards Institute, Inc., (ANSI) requirements for shipments of depleted UF6. A study has shown that an overpack can be designed and fabricated to satisfy these needs. The envisioned overpack will handle cylinder models 48G, 48X, and 48Y and will also comply with the ANSI N14.1 and the American Society of Mechanical Engineers (ASME) Sect. 8 requirements

  17. Safety analysis report on the ''Paducah Tiger'' overpack for 10-ton cylinder of uranium hexafluoride

    International Nuclear Information System (INIS)

    A summary of analysis performed to assess the puncture resistance of the Paducah Tiger under a particularly severe (worst case) orientation of the external puncture pin is presented. The six-inch diameter cylindrical puncture pin has been oriented to place its impact location immediately opposite the valve body mounted to the dished head of the uranium hexafluoride cylinder. The valve body is assumed to have a one-inch clearance relative to the inner wall of the overpack. Analysis indicates that significant residual kinetic energy remains in the system at the instant of overpack inner wall contact with the valve body. Thus, there is strong evidence suggesting that the valve body can be damaged, or sheared from the dished head of the UF6, under the assumed worst case impact orientation

  18. Sampling, characterization, and remote sensing of aerosols formed in the atmospheric hydrolysis of uranium hexafluoride

    International Nuclear Information System (INIS)

    When gaseous uranium hexafluoride (UF6) is released into the atmosphere, it rapidly reacts with ambient moisture to form an aerosol of uranyl fluoride (UO2F2) and hydrogen fluoride (HF). As part of our Safety Analysis program, we have performed several experimental releases of HF6 in contained volumes in order to investigate techniques for sampling and characterizing the aerosol materials. The aggregate particle morphology and size distribution have been found to be dependent upon several conditions, including the temperature of the UF6 at the time of its release, the relative humidity of the air into which it is released, and the elapsed time after the release. Aerosol composition and settling rate have been investigated using stationary samplers for the separate collection of UO2F2 and HF and via laser spectroscopic remote sensing (Mie scatter and infrared spectroscopy). 25 refs., 16 figs., 5 tabs

  19. Uranium hexafluoride packaging tiedown systems overview at Portsmouth Gaseous Diffusion Plant, Piketon, Ohio

    International Nuclear Information System (INIS)

    The Portsmouth Gaseous Diffusion Plant (PORTS) conducts those operations that are necessary for the production, packaging, and shipment of enriched uranium hexafluoride (UF6). Uranium hexafluoride enriched greater than 1.0 wt percent 235U shall be packaged in accordance with the US Department of Transportation (DOT) regulations of Title 49 CFR Parts 173 and 178, or in US Nuclear Regulatory Commission (NRC) or US Department of Energy (DOE) certified package designs. Concerns have been expressed regarding the various tiedown methods and condition of the trailers being used by some shippers/carriers for international transport of the UF6 cylinders/overpacks. The generally accepted method for securing the overpack during shipment is to bolt its base to the trailer bed. International shipments typically are not made using dedicated trailers, and numerous trailers have been received at PORTS with improperly and potentially dangerously secured overpacks. Also, many trailers have not been loaded at PORTS for international shipment because of mechanical problems, rotten flooring, bald tires, no brakes or brake lights, or broken springs. Because of the concerns about international shipments, the US Department of Energy-Headquarters (DOE-HQ) Office of Nuclear Energy, through DOE-HQ Transportation Management Division, requested Westinghouse Hanford Company to review UF6 packaging tiedown and shipping practices used by PORTS, and where possible and appropriate, provide recommendations for enhancing these practices. Consequently, a team of two individuals from Westinghouse Hanford visited PORTS on March 5 and 6, 1990, for the purpose of conducting this review. The paper provides a brief discussion of the review activities and a summary of the resulting findings and recommendations. A detailed reporting of the review is documented in Reference 4 [Report No. WHC-MR-0233

  20. Assessment of the risk of transporting uranium hexafluoride by truck and train

    Energy Technology Data Exchange (ETDEWEB)

    Geffen, C.A.; Johnson, J.F.; Davis, D.K.; Friley, J.R.; Ross, B.A.

    1978-08-01

    This report is the fifth in a series of studies of the risk of transporting potentially hazardous energy materials. The report presents an assessment of the risk of shipping uranium hexafluoride (UF/sub 6/) by truck and rail. The general risk assessment methodology, summarized in Section 3, used in this study is that developed for the first study in this series. The assessment includes the risks from release of uranium hexafluoride during truck or rail transport due to transportation accidents. The contribution to the risk of deteriorated or faulty packaging during normal transport was also considered. The report is sectioned to correspond to the specific analysis steps of the risk assessment model. The transportation system and accident environment are described in Sections 4 and 5. Calculation of the response of the shipping system to forces produced in transportation accidents are presented in Section 6 and the results of a survey to determine the condition of the package during transport are presented in Section 7. Sequences of events that could lead to a release of radioactive material from the shipping cask during transportation are postulated in Section 8 using fault tree analysis. These release sequences are evaluated in Sections 9 through 11, to determine both the likelihood and the possible consequences of each release. Supportive data and analyses are given in the appendices. The results of the risk assessment have been related to the year 1985, when it is projected that 100 GW of electric power will be generated annually by nuclear power plants. It was estimated that approximately 46,000 metric tons (MT) of natural UF/sub 6/ and 14,600 MT of enriched UF/sub 6/ would be shipped in the reference year.

  1. Preconceptual design studies and cost data of depleted uranium hexafluoride conversion plants

    International Nuclear Information System (INIS)

    One of the more important legacies left with the Department of Energy (DOE) after the privatization of the United States Enrichment Corporation is the large inventory of depleted uranium hexafluoride (DUF6). The DOE Office of Nuclear Energy, Science and Technology (NE) is responsible for the long-term management of some 700,000 metric tons of DUF6 stored at the sites of the two gaseous diffusion plants located at Paducah, Kentucky and Portsmouth, Ohio, and at the East Tennessee Technology Park in Oak Ridge, Tennessee. The DUF6 management program resides in NE's Office of Depleted Uranium Hexafluoride Management. The current DUF6 program has largely focused on the ongoing maintenance of the cylinders containing DUF6. However, the long-term management and eventual disposition of DUF6 is the subject of a Programmatic Environmental Impact Statement (PEIS) and Public Law 105-204. The first step for future use or disposition is to convert the material, which requires construction and long-term operation of one or more conversion plants. To help inform the DUF6 program's planning activities, it was necessary to perform design and cost studies of likely DUF6 conversion plants at the preconceptual level, beyond the PEIS considerations but not as detailed as required for conceptual designs of actual plants. This report contains the final results from such a preconceptual design study project. In this fast track, three month effort, Lawrence Livermore National Laboratory and Bechtel National Incorporated developed and evaluated seven different preconceptual design cases for a single plant. The preconceptual design, schedules, costs, and issues associated with specific DUF6 conversion approaches, operating periods, and ownership options were evaluated based on criteria established by DOE. The single-plant conversion options studied were similar to the dry-conversion process alternatives from the PEIS. For each of the seven cases considered, this report contains information on

  2. Assessment of the risk of transporting uranium hexafluoride by truck and train

    International Nuclear Information System (INIS)

    This report is the fifth in a series of studies of the risk of transporting potentially hazardous energy materials. The report presents an assessment of the risk of shipping uranium hexafluoride (UF6) by truck and rail. The general risk assessment methodology, summarized in Section 3, used in this study is that developed for the first study in this series. The assessment includes the risks from release of uranium hexafluoride during truck or rail transport due to transportation accidents. The contribution to the risk of deteriorated or faulty packaging during normal transport was also considered. The report is sectioned to correspond to the specific analysis steps of the risk assessment model. The transportation system and accident environment are described in Sections 4 and 5. Calculation of the response of the shipping system to forces produced in transportation accidents are presented in Section 6 and the results of a survey to determine the condition of the package during transport are presented in Section 7. Sequences of events that could lead to a release of radioactive material from the shipping cask during transportation are postulated in Section 8 using fault tree analysis. These release sequences are evaluated in Sections 9 through 11, to determine both the likelihood and the possible consequences of each release. Supportive data and analyses are given in the appendices. The results of the risk assessment have been related to the year 1985, when it is projected that 100 GW of electric power will be generated annually by nuclear power plants. It was estimated that approximately 46,000 metric tons (MT) of natural UF6 and 14,600 MT of enriched UF6 would be shipped in the reference year

  3. Uranium hexafluoride packaging tiedown systems overview at Portsmouth Gaseous Diffusion Plant, Piketon, Ohio

    International Nuclear Information System (INIS)

    The Portsmouth Gaseous Diffusion Plant (PORTS) in Piketon, Ohio, is operated by Martin Marietta Energy Systems, Inc., through the US Department of Energy-Oak Ridge Operations Office (DOE-ORO) for the US Department of Energy-Headquarters, Office of Nuclear Energy. The PORTS conducts those operations that are necessary for the production, packaging, and shipment of enriched uranium hexafluoride (UF6). Uranium hexafluoride enriched greater than 1.0 wt percent 235U shall be packaged in accordance with the US Department of Transportation (DOT) regulations of Title 49 CFR Parts 173 and 178, or in US Nuclear Regulatory Commission (NRC) or US Department of Energy (DOE) certified package designs. Concerns have been expressed regarding the various tiedown methods and condition of the trailers being used by some shippers/carriers for international transport of the UF6 cylinders/overpacks. International shipments typically are not made using dedicated trailers, and numerous trailers have been received at PORTS with improperly and potentially dangerously secured overpacks. Because of the concerns about international shipments, the US Department of Energy-Headquarters (DOE-HQ) Office of Nuclear Energy, through DOE-HQ Transportation Management Division, requested Westinghouse Hanford Company (Westinghouse Hanford) to review UF6 packaging tiedown and shipping practices used by PORTS; and where possible and appropriate, provide recommendations for enhancing these practices. Consequently, a team of two individuals from Westinghouse Hanford visited PORTS on March 5 and 6, 1990, for the purpose of conducting this review. The paper provides a brief discussion of the review activities and a summary of the resulting findings and recommendations

  4. Uranium hexafluoride packaging tiedown systems overview at Portsmouth Gaseous Diffusion Plant, Piketon, Ohio

    International Nuclear Information System (INIS)

    The Portsmouth Gaseous Diffusion Plant (PORTS) in Piketon, Ohio operated by Martin Marietta Energy Systems, Inc., through the US Department of Energy-Oak Ridge Operations Office (DOE-ORO) for the US Department of Energy Headquarters, Office of Nuclear Energy. The PORTS conducts those operations that are necessary for the production, packaging, and shipment of enriched uranium hexafluoride (UF6). Uranium hexafluoride enriched greater than 1.0 wt percent 235U shall be packaged in accordance with the US Department of Transportation (DOT) regulations of Title 49 CFR Parts 173 (Reference 1) and 178 (Reference 2), or in US Nuclear Regulatory Commission (NRC) or US Department of Energy (DOE) certified package designs. Concerns have been expressed regarding the various tiedown methods and condition of the trailers being used by some shippers/carriers for international transport of the UF6 cylinders/overpacks (Reference 3). Because of the concerns about international shipments, the US Department of Energy-Headquarters (DOE-HQ) Office of Nuclear Energy, through DOE-HQ Transportation Management Division, requested Westinghouse Hanford Company (Westinghouse Hanford) to review UF6 packaging tiedown and shipping practices used by PORTS, and where possible and appropriate, provide recommendations for enhancing these practices. Consequently, a tram of two individuals from Westinghouse Hanford visited PORTS on March 5 and 6, 1990, for the purpose of conducting this review. The paper provides a brief discussion of the review activities and a summary of the resulting findings and recommendations. A detailed reporting of the review is documented in Reference 4

  5. Uranium hexafluoride - chemistry and technology of a raw material of the nuclear fuel cycle

    International Nuclear Information System (INIS)

    Uranium hexafluoride exhibits an unusual combination of properties: UF6 is both a large-scale industrial product, and also one of the most reactive compounds known. Its industrial application arises from the need to use enriched uranium with up to 4% 235U as fuel in light water reactors. Enrichment is performed in isotope separation plants with UF6 as the working gas. Its volatility and thermal stability make UF6 suitable for this application. UF6 handling is difficult because of its high reactivity and its radioactivity, and special experience and equipment are required which are not commonly available in laboratories or industrial facilities. The chemical reactions of UF6 are characterized by its marked fluorination efficiency which is similar to that of F2. Of special importance in connection with the handling of UF6 is its extreme sensitivity to hydrolysis. Because they all use UF6, the isotope separation processes currently in use (gas diffusion, gas centrifuge, separation nozzle process) have a number of common features. For instance, they are all beset by the problem of formation of solid UF6 decomposition products, e.g. by radiolysis of UF6 molecules induced by its own radiation. Reconversion of UF6 into UO2 is achieved by three well-known methods (ADU, AUC, IDP-process). To produce uranium metal, UF6 is first reduced to UF4, which is subsequently reduced by Ca6 or Mg metal. 158 refs

  6. Some Investigations of the Reaction of Activated Charcoal with Fluorine and Uranium Hexafluoride

    Energy Technology Data Exchange (ETDEWEB)

    Del Cul, G.D.; Fiedor, J.N.; Simmons, D.W.; Toth, L.M.; Trowbridge, L.D.; Williams

    1998-09-01

    The Molten Salt Reactor Experiment (MSRE) at Oak Ridge National Laboratory has been shut down since 1969, when the fuel salt was drained from the core into two Hastelloy N drain tanks at the reactor site. Over time, fluorine (F{sub 2}) and uranium hexafluoride (UF{sub 6}) moved from the salt through the gas piping to a charcoal bed, where they reacted with the activated charcoal. Some of the immediate concerns related to the migration of F{sub 2} and UF{sub 6} to the charcoal bed were the possibility of explosive reactions between the charcoal and F{sub 2}, the existence of conditions that could induce a criticality accident, and the removal and recovery of the fissile uranium from the charcoal. This report addresses the reactions and reactivity of species produced by the reaction of fluorine and activated charcoal and between charcoal and F{sub 2}-UF{sub 6} gas mixtures in order to support remediation of the MSRE auxiliary charcoal bed (ACB) and the recovery of the fissile uranium. The chemical identity, stoichiometry, thermochemistry, and potential for explosive decomposition of the primary reaction product, fluorinated charcoal, was determined.

  7. Depleted uranium hexafluoride (DUF6) management system--a decision tool

    International Nuclear Information System (INIS)

    The Depleted Uranium Hexafluoride (DUF6) Management System (DMS) is being developed as a decision tool to provide cost and risk data for evaluation of short-and long-term management strategies for depleted uranium. It can be used to assist decision makers on a programmatic or site-specific level. Currently, the DMS allows evaluation of near-term cylinder management strategies such as storage yard improvements, cylinder restocking, and reconditioning. The DMS has been designed to provide the user with maximum flexibility for modifying data and impact factors (e.g., unit costs and risk factors). Sensitivity analysis can be performed on all key parameters such as cylinder corrosion rate, inspection frequency, and impact factors. Analysis may be conducted on a system-wide, site, or yard basis. The costs and risks from different scenarios may be compared in graphic or tabular format. Ongoing development of the DMS will allow similar evaluation of long-term management strategies such as conversion to other chemical forms. The DMS is a Microsoft Windows 3.1 based, stand-alone computer application. It can be operated on a 486 or faster computer with VGA, 4 MB of RAM, and 10 MB of disk space

  8. High-temperature corrosion testing of alumina and zirconia in uranium hexafluoride environment

    International Nuclear Information System (INIS)

    Uranium fluoride gases are proposed as primary candidate fuels for ultrahigh-temperature gas core or vapor core reactor systems for a variety of space power applications. In these systems, the peak temperature of the fissioning gas can be as high as 5000 K and the inner wall temperature of the reactor cavity is within the range of 1000 to 2000 K. Two kinds of alumina, sapphire and polycrystal alpha alumina, and CaO partially stabilized zirconia are exposed to uranium hexafluoride gas in temperatures ranging from 973 to 1473 K and from 873 to 1073 K, respectively. Exposure tests are conducted in a UF6 flowing loop with an alumina reaction tube housed in a 1500 K electric-heated furnace. The reaction rates are measured using a discontinuous gravimetric method. The morphology of the exposed surfaces was observed by optical microscopy and scanning electron microscopy, and the reaction products were identified by x-ray diffraction and energy dispersive x-ray spectroscopy. Results indicate that alumina provides a relatively higher service temperature in UF6 environment. However, due to the highly reactive and chemically aggressive nature of UF6 at high temperatures, the maximum service temperature of alumina for a UF6-based gas core reactor is limited to 1273 K. Zirconia at temperatures above 973 K is not compatible with UF6

  9. Modeling accidental releases to the atmosphere of a dense reactive chemical (Uranium hexafluoride)

    Science.gov (United States)

    Hanna, Steven R.; Chang, Joseph C.; Zhang, Xiaoming J.

    In order to model the atmospheric transport and dispersion of dense reactive chemicals such as uranium hexafluoride (UF 6), it is necessary to include algorithms that account for heat exchanges due to chemical reactions and phase changes. UF 6 may be released accidentally at uranium-enrichment plants as a warm gas from a pipeline rupture, or as a flashing liquid from a pressurized tank or line break. The resulting plume is initially very dense due to the large molecular weight of UF 6, but may become lighter-than-air as the UF 6 reacts with water vapor to form HF, which has a molecular weight less than that of air, and which may cause an increase in plume temperature due to the exothermic reaction. The major chemical and thermodynamic processes related to UF 6 have been incorporated in a modified version of an existing dense gas model, HGSYSTEM. The same general approach could be used to include other reactive chemicals in the modeling system. New modules that are applicable to any type of chemical release have also been added to HGSYSTEM to account for building downwash, lift-off of warm plumes from the ground, and deposition. The revised HGSYSTEM/UF 6 model has been evaluated with field data from UF 6 tests. The sensitivities of the model predictions to variations in input parameters have been assessed.

  10. On the remote monitoring of gaseous uranium hexafluoride in the lower atmosphere using lidar

    Science.gov (United States)

    Shayeganrad, Gholamreza

    2013-10-01

    Uranium hexafluoride (UF6), a major material for uranium enrichment, is highly toxic and can have adverse effects on the environment and human health if it escapes into the atmosphere. This paper proposes a contactless enhanced remote-sensing system for spatial and temporal detection of gaseous UF6 in the atmosphere and visualization of the leakage location. The system is composed of a combination of differential absorption lidar (DIAL) and Raman lidar for the simultaneous detection of gaseous UF6 and HF. The DIAL provides information on the UF6 concentration using a frequency-quadrupled Nd:YAG laser at 266 nm for the off-wavelength and a Nd:YAG-pumped Coumarin 450 dye laser using a Littrow grating mounting operating in the frequency-doubled mode at 245 nm for the on-wavelength. The Raman scattering of molecular HF at a wavelength of 297.3 nm (with a Raman frequency shift of 3959 cm-1) is a versatile technique used to identify the HF as a probe for real-time detection of the toxic UF6 leakage location. Combining the simultaneous measurements of UF6 and HF allows for a reduction of the uncertainty and an increase in the sensitivity of remote sensing of UF6.

  11. Uranium hexafluoride liquid thermal expansion, elusive eutectic with hydrogen fluoride, and very first production using chlorine trifluoride

    Energy Technology Data Exchange (ETDEWEB)

    Rutledge, G.P. [Central Environmental, Inc., Anchorage, AK (United States)

    1991-12-31

    Three unusual incidents and case histories involving uranium hexafluoride in the enrichment facilities of the USA in the late 1940`s and early 1950`s are presented. The history of the measurements of the thermal expansion of liquids containing fluorine atoms within the molecule is reviewed with special emphasis upon uranium hexafluoride. A comparison is made between fluorinated esters, fluorocarbons, and uranium hexafluoride. The quantitative relationship between the thermal expansion coefficient, a, of liquids and the critical temperature, T{sub c} is presented. Uranium hexafluoride has an a that is very high in a temperature range that is used by laboratory and production workers - much higher than any other liquid measured. This physical property of UF{sub 6} has resulted in accidents involving filling the UF{sub 6} containers too full and then heating with a resulting rupture of the container. Such an incident at a uranium gaseous diffusion plant is presented. Production workers seldom {open_quotes}see{close_quotes} uranium hexafluoride. The movement of UF{sub 6} from one container to another is usually trailed by weight, not sight. Even laboratory scientists seldom {open_quotes}see{close_quotes} solid or liquid UF{sub 6} and this can be a problem at times. This inability to {open_quotes}see{close_quotes} the UF{sub 6}-HF mixtures in the 61.2{degrees}C to 101{degrees}C temperature range caused a delay in the understanding of the phase diagram of UF{sub 6}-HF which has a liquid - liquid immiscible region that made the eutectic composition somewhat elusive. Transparent fluorothene tubes solved the problem both for the UF{sub 6}-HF phase diagram as well as the UF{sub 6}-HF-CIF{sub 3} phase diagram with a miscibility gap starting at 53{degrees}C. The historical background leading to the first use of CIF{sub 3} to produce UF{sub 6} in both the laboratory and plant at K-25 is presented.

  12. Hydraulic breakage of tanks for the transport of uranium hexafluoride (UF6)

    International Nuclear Information System (INIS)

    To begin with, the tank models that are proposed by the international norms for the transport and storage of hexafluoride of uranium (UF6) are briefly described. The operations related to the transport in its different forms are also described, particularly those that can produce the hydraulic breakage of tanks during its course or in later stages, when incorrectly performed. With reference to those operations, the most important physicochemical properties of UF6 as for safety are analyzed. A quantitative evaluation of the deviations of parameters that are controlled during the heating of tanks, comparing them with the normative nominal values, is performed. Adopting some simplifying hypothesis, a general study, applicable to all tank models proposed by norms, is carried out to determine the temperature at which the hydraulic breakage takes place when they are heated in closed-valve conditions. A curve is obtained by plotting the hydraulic breakage temperature against the filling degree. To conclude, the values obtained are compared with the results of other theoretical studies on this subject. (Author)

  13. Study of the hydrolysis of uranium hexafluoride by Fourier transform infrared spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, S.P.

    1982-08-01

    The reaction of uranium hexafluoride with water has been studied by using Fourier transform infrared (FT-IR) spectroscopy. Several different methods for accomplishing this task have been carried out. In addition, interpretatins of the results have been made. These interpretations have been based on literature values for the reactants and for compounds analogous to possible products. It was shown that classical matrix-isolation techniques proved to be unsatisfactory for studying this reaction. Other methods were developed in order to obtain results. They were: (1) the codeposition of pure UF/sub 6/ and H/sub 2/O on a cold window at 16/sup 0/K, (2) the codeposition of argon matrix to sample ratios of 10:1 to 2:1 of UF/sub 6/ and H/sub 2/O at 16/sup 0/K, and (3) the annealing of the samples produced by (1) and (2) while they were being scanned with FT-IR. 78 refs., 86 figs., 7 tabs.

  14. Application of the revised requirements of IAEA St-1 to the transport of natural uranium hexafluoride

    International Nuclear Information System (INIS)

    The 1996 issue of IAEA ST1 (formerly SS6) will, from january 2001, call for transport cylinders containing natural uranium hexafluoride ('hex') to be considered against the requirements of the IAEA thermal tests. In parallel with the revision of SS6, the IAEA established a coordinated research program (CRP) to consider the behaviour of hex cylinders in fires. BNFL has contributed to that CRP principally in the areas of computer modelling of the thermophysical processes occurring within the cylinder and of the mechanical behaviour of the cylinder itself. Confidence in the various computer simulations has grown steadily as the CRP progressed. With the benefit of results emerging from the Tenerife test program, our calculations now predict that an unprotected, fully loaded, 48Y hex cylinder would be expected to survive the thermal test. Since the expectation is that the unprotected fully loaded 48Y cylinders should (marginally) survive the fire test, and also taking account both of the excellent safety record to date of hex transports, and the rarity of intense long-lived fires in transport situations, there is clearly very little safety benefit to be gained from the use of fire protection covers on natural hex cylinders. However, the physical handling of such covers, necessarily large and cumbersome, and their relevant fastening, particularly during packaging, loading, unloading and un-packaging in transport depots would, for every cylinder movement, impose additional risks of injury to transport system operators, which we believe could outweigh the small and more hypothetical benefit of improved fire resistance while in transit. We therefore maintain that it would be counterproductive, in both overall safety and in cost terms, to require protective coverings on these cylinders for transport. Based on the estimates made to date, we believe that the unprotected 48 inch cylinders should continue to be the normal package in commercial use, under the relevant

  15. Safety evaluation of the transport container for natural uranium-hexafluoride under fire accident

    International Nuclear Information System (INIS)

    The land transportation of 48Y-cylinder filled with natural uranium-hexafluoride (UF6) is scheduled to start this year from Tokyo Harbor to the enrichment plant at Ningyou-pass in Okayama Prefecture. In this study, heat resistance capability analyses of 48Y-cylinder filled with 12.5-ton of natural UF6 under the condition of 800 C for the duration of 30 minutes were conducted. The authors developed a simple modeling technique for heat resistance analysis of UF6 packages which gives conservative and reasonable solutions, with two-dimensional or axi-symmetric models. Also, the effect of heat protective covers was examined analytically. The evaluated items of this 48Y-cylinder are as follows: The hydraulic breaking of cylinder by expansion of UF6 in liquid phase; The breaking of the cylinder by vapor pressure increasing of UF6 and the effect of the strength lowering of highly heated steel; and leakage of UF6 by melting soft solder of the valve and loss of integrity of containment. According to the results of preliminary analyses, temperature of 48Y-cylinder without heat protective instruments reached the melting point of soft solder (about 203 C) in 2 or 3 minutes after the analysis had started. From this point of view and public acceptance (PA), the authors determined to mount the heat protective covers, 14 mm thickness, in the both ends of the cylinder. Fire resistance analyses of the 48Y-cylinder filled with UF6 were carried out. As material properties of natural UF6, the data which were obtained through the study of PNC (Power Reactor and Nuclear Fuel Development Corporation) and the values listed in other papers were used. For numerical analysis, ABAQUS, a general purpose F.E.M. program for non-linear problems was used

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

    International Nuclear Information System (INIS)

    This report provides basic documentation of the FIREPLUME model and discusses its application to the prediction of health impacts resulting from releases of uranium hexafluoride (UF6) in fires. The model application outlined in this report was conducted for the Draft Programmatic Environmental Impact Statement for Alternative Strategies for the Long-Term Management and Use of Depleted UF6. The FIREPLUME model is an advanced stochastic model for atmospheric plume dispersion that predicts the downwind consequences of a release of toxic materials from an explosion or a fire. The model is based on the nonbuoyant atmospheric dispersion model MCLDM (Monte Carlo Lagrangian Dispersion Model), which has been shown to be consistent with available laboratory and field data. The inclusion of buoyancy and the addition of a postprocessor to evaluate time-varying concentrations lead to the current model. The FIREPLUME model, as applied to fire-related UF6 cylinder releases, accounts for three phases of release and dispersion. The first phase of release involves the hydraulic rupture of the cylinder due to heating of the UF6 in the fire. The second phase involves the emission of material into the burning fire, and the third phase involves the emission of material after the fire has died during the cool-down period. The model predicts the downwind concentration of the material as a function of time at any point downwind at or above the ground. All together, five fire-related release scenarios are examined in this report. For each scenario, downwind concentrations of the UF6 reaction products, uranyl fluoride and hydrogen fluoride, are provided for two meteorological conditions: (1) D stability with a 4-m/s wind speed, and (2) F stability with a 1-m/s wind speed

  17. Results of the remote sensing feasibility study for the uranium hexafluoride storage cylinder yard program

    Energy Technology Data Exchange (ETDEWEB)

    Balick, L.K.; Bowman, D.R. [Bechtel Nevada, Las Vegas, NV (United States). Remote Sensing Lab.; Bounds, J.H. [Los Alamos National Lab., NM (United States)] [and others

    1997-02-01

    The US DOE manages the safe storage of approximately 650,000 tons of depleted uranium hexafluoride remaining from the Cold War. This slightly radioactive, but chemically active, material is contained in more than 46,000 steel storage cylinders that are located at Oak Ridge, Tennessee; Paducah, Kentucky; and Portsmouth, Ohio. Some of the cylinders are more than 40 years old, and approximately 17,500 are considered problem cylinders because their physical integrity is questionable. These cylinders require an annual visual inspection. The remainder of the 46,000-plus cylinders must be visually inspected every four years. Currently, the cylinder inspection program is extremely labor intensive. Because these inspections are accomplished visually, they may not be effective in the early detection of leaking cylinders. The inspection program requires approximately 12--14 full-time-equivalent (FTE) employees. At the cost of approximately $125K per FTE, this translates to $1,500K per annum just for cylinder inspection. As part of the technology-development portion of the DOE Cylinder Management Program, the DOE Office of Facility Management requested the Remote Sensing Laboratory (RSL) to evaluate remote sensing techniques that have potential to increase the effectiveness of the inspection program and, at the same time, reduce inspection costs and personnel radiation exposure. During two site visits (March and May 1996) to the K-25 Site at Oak Ridge, TN, RSL personnel tested and characterized seven different operating systems believed to detect leakage, surface contamination, thickness and corrosion of cylinder walls, and general area contamination resulting from breached cylinders. The following techniques were used and their performances are discussed: Laser-induced fluorescent imaging; Long-range alpha detection; Neutron activation analysis; Differential gamma-ray attenuation; Compton scatterometry; Active infrared inspection; and Passive thermal infrared imaging.

  18. Selective excitation of branched vibrational ladder in uranium hexafluoride laser isotope separation

    International Nuclear Information System (INIS)

    Theoretical investigation was made on the dynamics of initial excitation process in molecular laser isotope separation for uranium hexafluoride (UF6) based on the generalized N-level density-matrix equation derived by Goodman et al. Branched vibrational model due to anharmonic-splitting components for the ν3 mode of UF6 molecule were formalized and phase interferences of density-matrix elements were considered to analyze the selective excitation. Because of a power-broadening effect, no more than 0.05J/cm2 fluence of a laser pulse completely masks high enrichment peaks in broadband (Δν = 2GHz) pumping case. Even when matching the laser frequency with ν3 band (n = 0 → 1) of 238UF6, the enrichment factor (α ≡ Rproduct/Rfeed, R ≡ [235UF6]/[238UF6]; R is the abundance ratio and [ ] means the mole fraction.) does not decrease. A narrow spectral linewidth (Δν = 400MHz) is shown to be essential to achieve a high concentration ratio in the system with a branched N-level ladder as expected from a general two-level system. The exciting frequency, which does not necessarily accord with the ν3 band of 235UF6, gives the maximum enrichment peak. Both the detuning of the optimum frequency and the sharp enrichment peak suggest a direct excitation due to multiphoton resonance. Spectral stability of the laser pulse is also required to excite only the desired isotope for the system with complicated anharmonic-splittings. (author)

  19. Results of the remote sensing feasibility study for the uranium hexafluoride storage cylinder yard program

    International Nuclear Information System (INIS)

    The US DOE manages the safe storage of approximately 650,000 tons of depleted uranium hexafluoride remaining from the Cold War. This slightly radioactive, but chemically active, material is contained in more than 46,000 steel storage cylinders that are located at Oak Ridge, Tennessee; Paducah, Kentucky; and Portsmouth, Ohio. Some of the cylinders are more than 40 years old, and approximately 17,500 are considered problem cylinders because their physical integrity is questionable. These cylinders require an annual visual inspection. The remainder of the 46,000-plus cylinders must be visually inspected every four years. Currently, the cylinder inspection program is extremely labor intensive. Because these inspections are accomplished visually, they may not be effective in the early detection of leaking cylinders. The inspection program requires approximately 12--14 full-time-equivalent (FTE) employees. At the cost of approximately $125K per FTE, this translates to $1,500K per annum just for cylinder inspection. As part of the technology-development portion of the DOE Cylinder Management Program, the DOE Office of Facility Management requested the Remote Sensing Laboratory (RSL) to evaluate remote sensing techniques that have potential to increase the effectiveness of the inspection program and, at the same time, reduce inspection costs and personnel radiation exposure. During two site visits (March and May 1996) to the K-25 Site at Oak Ridge, TN, RSL personnel tested and characterized seven different operating systems believed to detect leakage, surface contamination, thickness and corrosion of cylinder walls, and general area contamination resulting from breached cylinders. The following techniques were used and their performances are discussed: Laser-induced fluorescent imaging; Long-range alpha detection; Neutron activation analysis; Differential gamma-ray attenuation; Compton scatterometry; Active infrared inspection; and Passive thermal infrared imaging

  20. Uniform deposition of uranium hexafluoride (UF6): Standardized mass deposits and controlled isotopic ratios using a thermal fluorination method

    Energy Technology Data Exchange (ETDEWEB)

    McNamara, Bruce K.; O' Hara, Matthew J.; Casella, Andrew M.; Carter, Jennifer C.; Addleman, Raymond S.; MacFarlan, Paul J.

    2016-03-16

    Abstract: We report a convenient method for the generation of volatile uranium hexafluoride (UF6) from solid uranium oxides and other uranium compounds, followed by uniform deposition of low levels of UF6 onto sampling coupons. Under laminar flow conditions, UF6 is shown to interact with surfaces within the chamber to a highly predictable degree. We demonstrate the preparation of uranium deposits that range between ~0.01 and 470±34 ng∙cm-2. The data suggest the method can be extended to creating depositions at the sub-picogram∙cm-2 level. Additionally, the isotopic composition of the deposits can be customized by selection of the uranium source materials. We demonstrate a layering technique whereby two uranium solids, each with a different isotopic composition, are employed to form successive layers of UF6 on a surface. The result is an ultra-thin deposit of UF6 that bears an isotopic signature that is a composite of the two uranium sources. The reported deposition method has direct application to the development of unique analytical standards for nuclear safeguards and forensics.

  1. Compilation of Requirements for Safe Handling of Fluorine and Fluorine-Containing Products of Uranium Hexafluoride Conversion

    International Nuclear Information System (INIS)

    Public Law (PL) 105--204 requires the U.S. Department of Energy to develop a plan for inclusion in the fiscal year 2000 budget for conversion of the Department's stockpile of depleted uranium hexafluoride (DUF6) to a more stable form over an extended period. The conversion process into a more stable form will produce fluorine compounds (e.g., elemental fluorine or hydrofluoric acid) that need to be handled safely. This document compiles the requirements necessary to handle these materials within health and safety standards, which may apply in order to ensure protection of the environment and the safety and health of workers and the public

  2. Benchmark Gamma Spectroscopy Measurements of Uranium Hexafluoride in Aluminmum Pipe with a Sodium Iodide Detector

    Energy Technology Data Exchange (ETDEWEB)

    March-Leuba, Jose A [ORNL; Uckan, Taner [ORNL; Gunning, John E [ORNL; Brukiewa, Patrick D [ORNL; Upadhyaya, Belle R [ORNL; Revis, Stephen M [ORNL

    2010-01-01

    The expected increased demand in fuel for nuclear power plants, combined with the fact that a significant portion of the current supply from the blend down of weapons-source material will soon be coming to an end, has led to the need for new sources of enriched uranium for nuclear fuel. As a result, a number of countries have announced plans, or are currently building, gaseous centrifuge enrichment plants (GCEPs) to supply this material. GCEPs have the potential to produce uranium at enrichments above the level necessary for nuclear fuel purposes-enrichments that make the uranium potentially usable for nuclear weapons. As a result, there is a critical need to monitor these facilities to ensure that nuclear material is not inappropriately enriched or diverted for unintended use. Significant advances have been made in instrument capability since the current International Atomic Energy Agency (IAEA) monitoring methods were developed. In numerous cases, advances have been made in other fields that have the potential, with modest development, to be applied in safeguards applications at enrichment facilities. A particular example of one of these advances is the flow and enrichment monitor (FEMO). (See Gunning, J. E. et al., 'FEMO: A Flow and Enrichment Monitor for Verifying Compliance with International Safeguards Requirements at a Gas Centrifuge Enrichment Facility,' Proceedings of the 8th International Conference on Facility Operations - Safeguards Interface. Portland, Oregon, March 30-April 4th, 2008.) The FEMO is a conceptual instrument capable of continuously measuring, unattended, the enrichment and mass flow of {sup 235}U in pipes at a GCEP, and consequently increase the probability that the potential production of HEU and/or diversion of fissile material will be detected. The FEMO requires no piping penetrations and can be installed on pipes containing the flow of uranium hexafluoride (UF{sub 6}) at a GCEP. This FEMO consists of separate parts, a flow

  3. Draft Programmatic Environmental Impact Statement for alternative strategies for the long-term management and use of depleted uranium hexafluoride. Volume 2: Appendices

    International Nuclear Information System (INIS)

    This PEIS assesses the potential impacts of alternative management of alternative management strategies for depleted uranium hexafluoride (UF6) currently stored at three DOE sites: Paducah site near Paducah, Kentucky; Portsmouth site near Portsmouth, Ohio; and K-25 site on the Oak Ridge Reservation, Oak Ridge, Tennessee. The alternatives analyzed in the PEIS include no action, long-term storage as UF6, long-term storage as uranium oxide, use as uranium oxide, use as uranium metal, and disposal. The preferred alternative for the long-term management of depleted UF6 is to use the entire inventory of material. This volume contains the appendices to volume I

  4. Draft Programmatic Environmental Impact Statement for alternative strategies for the long-term management and use of depleted uranium hexafluoride. Volume 1: Main text

    International Nuclear Information System (INIS)

    This PEIS assesses the potential impacts of alternative management of alternative management strategies for depleted uranium hexafluoride (UF6) currently stored at three DOE sites: Paducah site near Paducah, Kentucky; Portsmouth site near Portsmouth, Ohio; and K-25 site on the Oak Ridge Reservation, Oak Ridge, Tennessee. The alternatives analyzed in the PEIS include no action, long-term storage as UF6, long-term storage as uranium oxide, use as uranium oxide, use as uranium metal, and disposal. The preferred alternative for the long-term management of depleted UF6 is to use the entire inventory of material

  5. Refurbishment of uranium hexafluoride cylinder storage yards C-745-K, L, M, N, and P and construction of a new uranium hexafluoride cylinder storage yard (C-745-T) at the Paducah Gaseous Diffusion Plant, Paducah, Kentucky

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-07-01

    The Paducah Gaseous Diffusion Plant (PGDP) is a uranium enrichment facility owned by the US Department of Energy (DOE). A residual of the uranium enrichment process is depleted uranium hexafluoride (UF6). Depleted UF6, a solid at ambient temperature, is stored in 32,200 steel cylinders that hold a maximum of 14 tons each. Storage conditions are suboptimal and have resulted in accelerated corrosion of cylinders, increasing the potential for a release of hazardous substances. Consequently, the DOE is proposing refurbishment of certain existing yards and construction of a new storage yard. This environmental assessment (EA) evaluates the impacts of the proposed action and no action and considers alternate sites for the proposed new storage yard. The proposed action includes (1) renovating five existing cylinder yards; (2) constructing a new UF6 storage yard; handling and onsite transport of cylinders among existing yards to accommodate construction; and (4) after refurbishment and construction, restacking of cylinders to meet spacing and inspection requirements. Based on the results of the analysis reported in the EA, DOE has determined that the proposed action is not a major Federal action that would significantly affect the quality of the human environment within the context of the National Environmental Policy Act of 1969. Therefore, DOE is issuing a Finding of No Significant Impact. Additionally, it is reported in this EA that the loss of less than one acre of wetlands at the proposed project site would not be a significant adverse impact.

  6. Refurbishment of uranium hexafluoride cylinder storage yards C-745-K, L, M, N, and P and construction of a new uranium hexafluoride cylinder storage yard (C-745-T) at the Paducah Gaseous Diffusion Plant, Paducah, Kentucky

    International Nuclear Information System (INIS)

    The Paducah Gaseous Diffusion Plant (PGDP) is a uranium enrichment facility owned by the US Department of Energy (DOE). A residual of the uranium enrichment process is depleted uranium hexafluoride (UF6). Depleted UF6, a solid at ambient temperature, is stored in 32,200 steel cylinders that hold a maximum of 14 tons each. Storage conditions are suboptimal and have resulted in accelerated corrosion of cylinders, increasing the potential for a release of hazardous substances. Consequently, the DOE is proposing refurbishment of certain existing yards and construction of a new storage yard. This environmental assessment (EA) evaluates the impacts of the proposed action and no action and considers alternate sites for the proposed new storage yard. The proposed action includes (1) renovating five existing cylinder yards; (2) constructing a new UF6 storage yard; handling and onsite transport of cylinders among existing yards to accommodate construction; and (4) after refurbishment and construction, restacking of cylinders to meet spacing and inspection requirements. Based on the results of the analysis reported in the EA, DOE has determined that the proposed action is not a major Federal action that would significantly affect the quality of the human environment within the context of the National Environmental Policy Act of 1969. Therefore, DOE is issuing a Finding of No Significant Impact. Additionally, it is reported in this EA that the loss of less than one acre of wetlands at the proposed project site would not be a significant adverse impact

  7. Technology, Safety and Costs of Decommissioning a Reference Uranium Hexafluoride Conversion Plant

    Energy Technology Data Exchange (ETDEWEB)

    Elder, H. K.

    1981-10-01

    Safety and cost information is developed for the conceptual decommissioning of a commercial uranium hexafluoride conversion (UF{sub 6}) plant. Two basic decommissioning alternatives are studied to obtain comparisons between cost and safety impacts: DECON, and passive SAFSTOR. A third alternative, DECON of the plant and equipment with stabilization and long-term care of lagoon wastes. is also examined. DECON includes the immediate removal (following plant shutdown) of all radioactivity in excess of unrestricted release levels, with subsequent release of the site for public use. Passive SAFSTOR requires decontamination, preparation, maintenance, and surveillance for a period of time after shutdown, followed by deferred decontamination and unrestricted release. DECON with stabilization and long-term care of lagoon wastes (process wastes generated at the reference plant and stored onsite during plant operation} is also considered as a decommissioning method, although its acceptability has not yet been determined by the NRC. The decommissioning methods assumed for use in each decommissioning alternative are based on state-of-the-art technology. The elapsed time following plant shutdown required to perform the decommissioning work in each alternative is estimated to be: for DECON, 8 months; for passive SAFSTOR, 3 months to prepare the plant for safe storage and 8 months to accomplish deferred decontamination. Planning and preparation for decommissioning prior to plant shutdown is estimated to require about 6 months for either DECON or passive SAFSTOR. Planning and preparation prior to starting deferred decontamination is estimated to require an additional 6 months. OECON with lagoon waste stabilization is estimated to take 6 months for planning and about 8 months to perform the decommissioning work. Decommissioning cost, in 1981 dollars, is estimated to be $5.91 million for OECON. For passive SAFSTOR, preparing the facility for safe storage is estimated to cost $0

  8. Standard Test Method for Isotopic Analysis of Uranium Hexafluoride by Single-Standard Gas Source Multiple Collector Mass Spectrometer Method

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This test method is applicable to the isotopic analysis of uranium hexafluoride (UF6) with 235U concentrations less than or equal to 5 % and 234U, 236U concentrations of 0.0002 to 0.1 %. 1.2 This test method may be applicable to the analysis of the entire range of 235U isotopic compositions providing that adequate Certified Reference Materials (CRMs or traceable standards) are available. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety health practices and determine the applicability of regulatory limitations prior to use.

  9. Standard test method for gamma energy emission from fission products in uranium hexafluoride and uranyl nitrate solution

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This test method covers the measurement of gamma energy emitted from fission products in uranium hexafluoride (UF6) and uranyl nitrate solution. It is intended to provide a method for demonstrating compliance with UF6 specifications C 787 and C 996 and uranyl nitrate specification C 788. 1.2 The lower limit of detection is 5000 MeV Bq/kg (MeV/kg per second) of uranium and is the square root of the sum of the squares of the individual reporting limits of the nuclides to be measured. The limit of detection was determined on a pure, aged natural uranium (ANU) solution. The value is dependent upon detector efficiency and background. 1.3 The nuclides to be measured are106Ru/ 106Rh, 103Ru,137Cs, 144Ce, 144Pr, 141Ce, 95Zr, 95Nb, and 125Sb. Other gamma energy-emitting fission nuclides present in the spectrum at detectable levels should be identified and quantified as required by the data quality objectives. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its us...

  10. Final programmatic environmental impact statement for alternative strategies for the long-term management and use of depleted uranium hexafluoride. Volume 1: Main text

    International Nuclear Information System (INIS)

    This PEIS assesses the potential impacts of alternative management strategies for depleted uranium hexafluoride (UF6) currently stored at three DOE sites: Paducah site near Paducah, Kentucky, Portsmouth site near Portsmouth, Ohio; and K-25 site on the Oak Ridge Reservation, Oak Ridge, Tennessee. The alternatives analyzed in the PEIS include no action, long-term storage as UF6, long-term storage as uranium oxide, use as uranium oxide, use as uranium metal, and disposal. DOE's preferred alternative is to begin conversion of the depleted UF6 inventory as soon as possible, either to uranium oxide, uranium metal, or a combination of both, while allowing for use of as much of this inventory as possible

  11. Final programmatic environmental impact statement for alternative strategies for the long-term management and use of depleted uranium hexafluoride. Volume 2: Appendices

    International Nuclear Information System (INIS)

    This PEIS assesses the potential impacts of alternative management strategies for depleted uranium hexafluoride (UF6) currently stored at three DOE sites: Paducah site near Paducah, Kentucky, Portsmouth site near Portsmouth, Ohio; and K-25 site on the Oak Ridge Reservation, Oak Ridge, Tennessee. The alternatives analyzed in the PEIS include no action, long-term storage as UF6, long-term storage as uranium oxide, use as uranium oxide, use as uranium metal, and disposal. DOE's preferred alternative is to begin conversion of the depleted UF6 inventory as soon as possible, either to uranium oxide, uranium metal, or a combination of both, while allowing for use of as much of this inventory as possible. This volume contains Appendices A--O

  12. Gas-phase thermal dissociation of uranium hexafluoride: Investigation by the technique of laser-powered homogeneous pyrolysis

    International Nuclear Information System (INIS)

    In the gas-phase, uranium hexafluoride decomposes thermally in a quasi-unimolecular reaction to yield uranium pentafluoride and atomic fluorine. We have investigated this reaction using the relatively new technique of laser-powered homogeneous pyrolysis, in which a megawatt infrared laser is used to generate short pulses of high gas temperatures under strictly homogeneous conditions. In our investigation, SiF4 is used as the sensitizer to absorb energy from a pulsed CO2 laser and to transfer this energy by collisions with the reactant gas. Ethyl chloride is used as an external standard ''thermometer'' gas to permit estimation of the unimolecular reaction rate constants by a relative rate approach. When UF6 is the reactant, CF3Cl is used as reagent to trap atomic fluorine reaction product, forming CF4 as a stable indicator which is easily detected by infrared spectroscopy. Using these techniques, we estimate the UF6 unimolecular reaction rate constant near the high-pressure limit. In the Appendix, we describe a computer program, written for the IBM PC, which predicts unimolecular rate constants based on the Rice-Ramsperger-Kassel theory. Parameterization of the theoretical model is discussed, and recommendations are made for ''appropriate'' input parameters for use in predicting the gas-phase unimolecular reaction rate for UF6 as a function of temperature and gas composition and total pressure. 85 refs., 17 figs., 14 tabs

  13. Uniform deposition of uranium hexafluoride (UF6): Standardized mass deposits and controlled isotopic ratios using a thermal fluorination method.

    Science.gov (United States)

    McNamara, Bruce K; O'Hara, Matthew J; Casella, Andrew M; Carter, Jennifer C; Addleman, R Shane; MacFarlan, Paul J

    2016-07-01

    We report a convenient method for the generation of volatile uranium hexafluoride (UF6) from solid uranium oxides and other U compounds, followed by uniform deposition of low levels of UF6 onto sampling coupons. Under laminar flow conditions, UF6 is shown to interact with surfaces within a fixed reactor geometry to a highly predictable degree. We demonstrate the preparation of U deposits that range between approximately 0.01 and 500ngcm(-2). The data suggest the method can be extended to creating depositions at the sub-picogramcm(-2) level. The isotopic composition of the deposits can be customized by selection of the U source materials and we demonstrate a layering technique whereby two U solids, each with a different isotopic composition, are employed to form successive layers of UF6 on a surface. The result is an ultra-thin deposit that bears an isotopic signature that is a composite of the two U sources. The reported deposition method has direct application to the development of unique analytical standards for nuclear safeguards and forensics. Further, the method allows access to very low atomic or molecular coverages of surfaces. PMID:27154668

  14. Standard test method for isotopic analysis of hydrolyzed uranium hexafluoride and uranyl nitrate solutions by thermal ionization mass spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This method applies to the determination of isotopic composition in hydrolyzed nuclear grade uranium hexafluoride. It covers isotopic abundance of 235U between 0.1 and 5.0 % mass fraction, abundance of 234U between 0.0055 and 0.05 % mass fraction, and abundance of 236U between 0.0003 and 0.5 % mass fraction. This test method may be applicable to other isotopic abundance providing that corresponding standards are available. 1.2 This test method can apply to uranyl nitrate solutions. This can be achieved either by transforming the uranyl nitrate solution to a uranyl fluoride solution prior to the deposition on the filaments or directly by depositing the uranyl nitrate solution on the filaments. In the latter case, a calibration with uranyl nitrate standards must be performed. 1.3 This test method can also apply to other nuclear grade matrices (for example, uranium oxides) by providing a chemical transformation to uranyl fluoride or uranyl nitrate solution. 1.4 This standard does not purport to address al...

  15. Standard test method for isotopic analysis of uranium hexafluoride by double standard single-collector gas mass spectrometer method

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This is a quantitative test method applicable to determining the mass percent of uranium isotopes in uranium hexafluoride (UF6) samples with 235U concentrations between 0.1 and 5.0 mass %. 1.2 This test method may be applicable for the entire range of 235U concentrations for which adequate standards are available. 1.3 This test method is for analysis by a gas magnetic sector mass spectrometer with a single collector using interpolation to determine the isotopic concentration of an unknown sample between two characterized UF6 standards. 1.4 This test method is to replace the existing test method currently published in Test Methods C761 and is used in the nuclear fuel cycle for UF6 isotopic analyses. 1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro...

  16. Field-testing of a new portable HPGe detector system using the enrichment meter principle for the inspection of uranium oxide and hexafluoride in containers

    International Nuclear Information System (INIS)

    The purpose of this study was to develop a new portable detector system for the measurement of uranium enrichment of Uranium oxide and Uranium hexafluoride samples in containers. In this paper the authors describe such an apparatus that consisted of high purity germanium detector, a collimator, Canberra InSpector trademark and a laptop computer. In addition, the portable enrichment measurement system used Canberra Genie-PC trademark software for data acquisition and specialized software written for this application for the data analysis. In this paper they briefly discuss the unique features of this system. They also give the results of measurements made on both Highly Enriched Uranium (HEU) and Low Enriched Uranium (LEU) samples at the Portsmouth Gaseous Diffusion Plant

  17. Criticality and characteristic neutronic analysis of a transient-state shockwave in a pulsed spherical gaseous uranium-hexafluoride reactor

    Science.gov (United States)

    Boles, Jeremiah Thomas

    The purpose of this study is to analyze the theoretical criticality of a spherical uranium-hexafluoride reactor with a transient, pulsed shockwave emanating from the center of the sphere in an outward-radial direction. This novel nuclear reactor design, based upon pulsed fission in a spherical enclosure is proposed for possible use in direct energy conversion, where the energy from fission products is captured through the use of electrostatic fields or through induction. An analysis of the dynamic behavior of the shockwave in this reactor is the subject of this thesis. As a shockwave travels through a fluid medium, the characteristics of the medium will change across the shockwave boundary. Pressure, temperature, and density are all affected by the shockwave. Changes in these parameters will affect the neutronic characteristics of a fissile medium. If the system is initially in a subcritical state, the increases in pressure, temperature, and density, all brought about by the introduction of the shockwave, will increase the reactivity of the nuclear system, creating a brief super critical state that will return to a subcritical state after the shockwave dissipates. Two major problems are required to be solved for this system. One is the effects of the shockwave on the gas, and the second is the resulting effects on system criticality. These problems are coupled due to the unique nature of the speed of the expanding shockwave in the uranium-hexafluoride medium and the energy imparted to the system by the shockwave with respect to the fissile uranium-hexafluoride. Using compressible flow and shockwave theories, this study determines the properties of the gaseous medium for reference points before, during, and behind the shockwave as it passes through the fissile medium. These properties include pressure changes, temperature changes, and density changes that occur to the system. Using the parameters calculated from the shockwave, the neutron transport equation is

  18. A validation study of the intertran model for assessing risks of transportation accidents: Road transport of uranium hexafluoride

    International Nuclear Information System (INIS)

    The INTERTRAN code was developed by the IAEA in order to provide member states with a simple and rapide method of assessing the risk involved in the transportation of radioactive materials and one which was applicable on a worldwide scale. Before being used, this code must be validated and the CEA thus compared the results obtained with the conventional risk assessment methods used by the CEPN with those derived from INTERTRAN. This paper gives the results of the studies made on the subject of road transportation of uranium hexafluoride in France. The conventional accident risk assessment method gave a figure of 8.84 x 10-4 deaths/year, whereas INTERTRAN announces 1.78 x 10-2. To these figures should be added 3.38 x 10-2 deaths/year, which is the intrinsic road risk, whatever the goods carried. In relation to conventional estimates, the INTERTRAN forecasts are five times lower for the U risk and twenty times higher for the HF risk. The chemical risk is indeed the most prevalent one in this case. Other comparisons are needed to validate this code

  19. A Peer Review of the Strategy for Characterizing Ransuranics and Technetium Contamination in Uranium Hexafluoride Tails Cylinders

    International Nuclear Information System (INIS)

    This document provides the findings from a peer review of the Oak Ridge National Laboratory (ORNL) Hightower 2000 study, which set forth a strategy for characterization of low levels of radioactive contaminants in depleted uranium hexafluoride (DUF6) cylinders at the Oak Ridge, Paducah, and Portsmouth gaseous diffusion plants. The information from that study will be used in a DOE-issued request for proposal (RFP) for conversion services from the private sector, to assist vendors in reducing costs associated with contingencies relating to handling this DUF6 with elevated transuranics (TRUs) and technetium (Tc). The Hightower study developed a general strategy for DUF6 sampling and analysis in accordance with their task but also recommended the following courses of action: (a) Collect and analyze liquid samples from the two identified Paducah Gaseous Diffusion Plant (PGDP) feed cylinders, feed the DUF6 into the cascades, and conduct an analysis on the resulting heels by washing and analyzing the wash rinsate; (b) Characterize the cylinder coatings to determine the extent and levels of polychlorinated biphenyl (PCB) contamination; and (c) Verify the characterization of the cylinder inventory's compliance with Department of Transportation (DOT) regulations and the American Society of Mechanical Engineers (ASME) pressure vessel code In addition to the above recommendations, the study also concluded that additional characterization is not likely to result in lower bids by prospective vendors, and that direct sampling of many older tails cylinders may be impractical

  20. A Peer Review of the Strategy for Characterizing Ransuranics and Technetium Contamination in Uranium Hexafluoride Tails Cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Sengupta, S.K.; Randich, E.; Avci, H.I.; Steindler, M.J.; Brumburgh, G.P.

    2000-09-01

    This document provides the findings from a peer review of the Oak Ridge National Laboratory (ORNL) Hightower 2000 study, which set forth a strategy for characterization of low levels of radioactive contaminants in depleted uranium hexafluoride (DUF{sub 6}) cylinders at the Oak Ridge, Paducah, and Portsmouth gaseous diffusion plants. The information from that study will be used in a DOE-issued request for proposal (RFP) for conversion services from the private sector, to assist vendors in reducing costs associated with contingencies relating to handling this DUF{sub 6} with elevated transuranics (TRUs) and technetium (Tc). The Hightower study developed a general strategy for DUF{sub 6} sampling and analysis in accordance with their task but also recommended the following courses of action: (a) Collect and analyze liquid samples from the two identified Paducah Gaseous Diffusion Plant (PGDP) feed cylinders, feed the DUF{sub 6} into the cascades, and conduct an analysis on the resulting heels by washing and analyzing the wash rinsate; (b) Characterize the cylinder coatings to determine the extent and levels of polychlorinated biphenyl (PCB) contamination; and (c) Verify the characterization of the cylinder inventory's compliance with Department of Transportation (DOT) regulations and the American Society of Mechanical Engineers (ASME) pressure vessel code In addition to the above recommendations, the study also concluded that additional characterization is not likely to result in lower bids by prospective vendors, and that direct sampling of many older tails cylinders may be impractical.

  1. Gas-phase thermal dissociation of uranium hexafluoride: Investigation by the technique of laser-powered homogeneous pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Bostick, W.D.; McCulla, W.H.; Trowbridge, L.D.

    1987-04-01

    In the gas-phase, uranium hexafluoride decomposes thermally in a quasi-unimolecular reaction to yield uranium pentafluoride and atomic fluorine. We have investigated this reaction using the relatively new technique of laser-powered homogeneous pyrolysis, in which a megawatt infrared laser is used to generate short pulses of high gas temperatures under strictly homogeneous conditions. In our investigation, SiF/sub 4/ is used as the sensitizer to absorb energy from a pulsed CO/sub 2/ laser and to transfer this energy by collisions with the reactant gas. Ethyl chloride is used as an external standard ''thermometer'' gas to permit estimation of the unimolecular reaction rate constants by a relative rate approach. When UF/sub 6/ is the reactant, CF/sub 3/Cl is used as reagent to trap atomic fluorine reaction product, forming CF/sub 4/ as a stable indicator which is easily detected by infrared spectroscopy. Using these techniques, we estimate the UF/sub 6/ unimolecular reaction rate constant near the high-pressure limit. In the Appendix, we describe a computer program, written for the IBM PC, which predicts unimolecular rate constants based on the Rice-Ramsperger-Kassel theory. Parameterization of the theoretical model is discussed, and recommendations are made for ''appropriate'' input parameters for use in predicting the gas-phase unimolecular reaction rate for UF/sub 6/ as a function of temperature and gas composition and total pressure. 85 refs., 17 figs., 14 tabs.

  2. Transport, chemistry, and thermodynamics of uranium hexafluoride in the atmosphere—evaluation of models using field data

    Science.gov (United States)

    Nair, Shyam K.; Chambers, Douglas B.; Radonjic, Zivorad; Park, Shin

    Accidental releases of uranium hexafluoride (UF 6) can occur from nuclear fuel cycle facilities. Upon release to the atmosphere, UF 6 enters into exothermic chemical reactions with atmospheric water vapor producing hydrogen fluoride (HF) and uranyl fluoride (UO 2F 2); HF undergoes further polymerization, depolymerization, and hydrolysis. A number of models have been used in the past to simulate the transport of UF 6 and its reaction products in the atmosphere. Performances of two models, HGSYSTEM/UF 6 and SAIC were assessed by comparing model predictions with field measurements. Field data for UF 6 were available from three experimental releases made at Bordeaux in France between 1986 and 1989; an accidental release at Gore, Oklahoma; and an accidental release at the Comurhex Plant in France. The Gore and Comurhex data are of questionable quality since they were from a real accident. The Bordeaux data are of better quality since they were from a research-grade study. Predictions from the HGSYSTEM/UF 6 model were within an order of magnitude of the observations, with most within a factor of two of the observations. Most predictions from the SAIC model were within an order of magnitude of the observations, but the model also over-predicted beyond an order of magnitude for a few observations. Detailed sensitivity analyses were also conducted on all modules of the HGSYSTEM/UF 6 and SAIC models. At large distances from the source, the output concentration of total uranium is most sensitive to meteorological parameters; and at distances close to the source, it is most sensitive to certain source-specific and meteorological parameters.

  3. Draft Environmental Impact Statement for Construction and Operation of a Depleted Uranium Hexafluoride Conversion Facility at the Portsmouth, Ohio, Site

    International Nuclear Information System (INIS)

    This document is a site-specific environmental impact statement (EIS) for construction and operation of a proposed depleted uranium hexafluoride (DUF6) conversion facility at the U.S. Department of Energy (DOE) Portsmouth site in Ohio (Figure S-1). The proposed facility would convert the DUF6 stored at Portsmouth to a more stable chemical form suitable for use or disposal. The facility would also convert the DUF6 from the East Tennessee Technology Park (ETTP) site near Oak Ridge, Tennessee. In a Notice of Intent (NOI) published in the Federal Register on September 18, 2001 (Federal Register, Volume 66, page 48123 [66 FR 48123]), DOE announced its intention to prepare a single EIS for a proposal to construct, operate, maintain, and decontaminate and decommission two DUF6 conversion facilities at Portsmouth, Ohio, and Paducah, Kentucky, in accordance with the National Environmental Policy Act of 1969 (NEPA) (United States Code, Title 42, Section 4321 et seq. [42 USC 4321 et seq.]) and DOE's NEPA implementing procedures (Code of Federal Regulations, Title 10, Part 1021 [10 CFR Part 1021]). Subsequent to award of a contract to Uranium Disposition Services, LLC (hereafter referred to as UDS), Oak Ridge, Tennessee, on August 29, 2002, for design, construction, and operation of DUF6 conversion facilities at Portsmouth and Paducah, DOE reevaluated its approach to the NEPA process and decided to prepare separate site-specific EISs. This change was announced in a Federal Register Notice of Change in NEPA Compliance Approach published on April 28, 2003 (68 FR 22368); the Notice is included as Attachment B to Appendix C of this EIS. This EIS addresses the potential environmental impacts from the construction, operation, maintenance, and decontamination and decommissioning (DandD) of the proposed conversion facility at three alternative locations within the Portsmouth site; from the transportation of all ETTP cylinders (DUF6, low-enriched UF6 [LEU-UF6], and empty) to Portsmouth

  4. Reuse of ammonium fluoride generated in the uranium hexafluoride conversion; Reutilizacao do fluoreto de amonio gerado na reconversao do hexafluoreto de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Silva Neto, J.B.; Carvalho, E.F. Urano de; Durazzo, M., E-mail: jbsneto@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Riella, H.G [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil)

    2010-07-01

    The Nuclear Fuel Centre of IPEN / CNEN - SP develops and manufactures dispersion fuel with high uranium concentration to meet the demand of the IEA-R1 reactor and future research reactors planned to be constructed in Brazil. The fuel uses uranium silicide (U{sub 3}Si{sub 2}) dispersed in aluminum. For producing the fuel, the processes for uranium hexafluoride (UF{sub 6}) conversion consist in obtaining U{sub 3}Si{sub 2} and / or U{sub 3}O{sub 8} through the preparation of intermediate compounds, among them ammonium uranyl carbonate - AUC, ammonium diuranate - DUA and uranium tetrafluoride - UF{sub 4}. This work describes a procedure for preparing uranium tetrafluoride by a dry route using as raw material the filtrate generated when producing routinely ammonium uranyl carbonate. The filtrate consists primarily of a solution containing high concentrations of ammonium (NH{sub 4}{sup +}), fluoride (F{sup -}), carbonate (CO{sub 3}{sup --}) and low concentrations of uranium. The procedure is basically the recovery of NH{sub 4}F and uranium, as UF{sub 4}, through the crystallization of ammonium bifluoride (NH{sub 4}HF{sub 2}) and, in a later step, the addition of UO{sub 2}, occurring fluoridation and decomposition. The UF{sub 4} obtained is further diluted in the UF{sub 4} produced routinely at IPEN / CNEN-SP by a wet route process. (author)

  5. Final programmatic environmental impact statement for alternative strategies for the long-term management and use of depleted uranium hexafluoride. Volume 3: Responses to public comments

    International Nuclear Information System (INIS)

    This PEIS assesses the potential impacts of alternative management strategies for depleted uranium hexafluoride (UF6) currently stored at three DOE sites: Paducah site near Paducah, Kentucky, Portsmouth site near Portsmouth, Ohio; and K-25 site on the Oak Ridge Reservation, Oak Ridge, Tennessee. The alternatives analyzed in the PEIS include no action, long-term storage as UF6, long-term storage as uranium oxide, use as uranium oxide, use as uranium metal, and disposal. DOE's preferred alternative is to begin conversion of the depleted UF6 inventory as soon as possible, either to uranium oxide, uranium metal, or a combination of both, while allowing for use of as much of this inventory as possible. This volume of the Final PEIS contains the comments and DOE's responses to comments received during the comment period. Chapter 2 contains photocopies of written submissions received by DOE on the Draft PEIS; DOE's responses to those comments are listed in Chapter 3. Chapter 4 provides the oral comments received at the public hearings and DOE's responses. Chapter 5 provides indices to comments and responses arranged by commentor name and by comment number

  6. Evaluation of the Acceptability of Potential Depleted Uranium Hexafluoride Conversion Products at the Envirocare Disposal Site

    International Nuclear Information System (INIS)

    The purpose of this report is to review and document the capability of potential products of depleted UF6 conversion to meet the current waste acceptance criteria and other regulatory requirements for disposal at the facility in Clive, Utah, owned by Envirocare of Utah, Inc. The investigation was conducted by identifying issues potentially related to disposal of depleted uranium (DU) products at Envirocare and conducting an initial analysis of them. Discussions were then held with representatives of Envirocare, the state of Utah (which is a NRC Agreement State and, thus, is the cognizant regulatory authority for Envirocare), and DOE Oak Ridge Operations. Provisional issue resolution was then established based on the analysis and discussions and documented in a draft report. The draft report was then reviewed by those providing information and revisions were made, which resulted in this document. Issues that were examined for resolution were (1) license receipt limits for U isotopes; (2) DU product classification as Class A waste; (3) use of non-DOE disposal sites for disposal of DOE material; (4) historical NRC views; (5) definition of chemical reactivity; (6) presence of mobile radionuclides; and (7) National Environmental Policy Act coverage of disposal. The conclusion of this analysis is that an amendment to the Envirocare license issued on October 5, 2000, has reduced the uncertainties regarding disposal of the DU product at Envirocare to the point that they are now comparable with uncertainties associated with the disposal of the DU product at the Nevada Test Site that were discussed in an earlier report

  7. Adsorption of molybdenum hexafluoride on magnesium difluoride for uranium purification in FLUOREX reprocessing

    International Nuclear Information System (INIS)

    The nuclear fuel reprocessing method FLUOREX is a hybrid system based on fluoride volatility and using solvent extraction. Spent nuclear fuel is fluorinated, and most of the uranium is recovered as UF6 gas. UF6 contains some volatile fission product (FP) fluorides, so we considered their elimination from UF6 by adsorbing them on fluoride adsorbents. We experimentally examined the adsorption of MoF6 on MgF2 adsorbent; MoF6 is present as a volatile FP fluoride in UF6 produced by the fluorination of spent nuclear fuel. The adsorption isotherm of MoF6 adsorption on MgF2 was obtained at MoF6 pressures from 10-4 to 50 kPa. The saturated adsorption amount was 1.3±0.4 mg/m2 at MoF6 pressures from 10-4 to 1 kPa. At MoF6 pressure of about 10-3 kPa, the saturated adsorption amount had no dependence on adsorption temperatures from 398 to 463 K. We deduced that MoF6 was adsorbed as a monomolecule layer on the MgF2 surface at MoF6 pressures from 10-4 to 1 kPa, and the MoF6 partial pressure in UF6 could be decreased below 1 x 10-4 kPa, which is the specific MoF6 concentration for the reenrichment process. (author)

  8. Compilation of Requirements for Safe Handling of Fluorine and Fluorine-Containing Products of Uranium Hexafluoride Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Ferrada, J.J.

    2000-04-03

    Public Law (PL) 105-204 requires the U.S. Department of Energy to develop a plan for inclusion in the fiscal year 2000 budget for conversion of the Department's stockpile of depleted uranium hexafluoride (DUF{sub 6}) to a more stable form over an extended period. The conversion process into a more stable form will produce fluorine compounds (e.g., elemental fluorine or hydrofluoric acid) that need to be handled safely. This document compiles the requirements necessary to handle these materials within health and safety standards, which may apply in order to ensure protection of the environment and the safety and health of workers and the public. Fluorine is a pale-yellow gas with a pungent, irritating odor. It is the most reactive nonmetal and will react vigorously with most oxidizable substances at room temperature, frequently with ignition. Fluorine is a severe irritant of the eyes, mucous membranes, skin, and lungs. In humans, the inhalation of high concentrations causes laryngeal spasm and broncospasms, followed by the delayed onset of pulmonary edema. At sublethal levels, severe local irritation and laryngeal spasm will preclude voluntary exposure to high concentrations, unless the individual is trapped or incapacitated. A blast of fluorine gas on the shaved skin of a rabbit causes a second degree burn. Lower concentrations cause severe burns of insidious onset, resulting in ulceration, similar to the effects produced by hydrogen fluoride. Hydrofluoric acid is a colorless, fuming liquid or gas with a pungent odor. It is soluble in water with release of heat. Ingestion of an estimated 1.5 grams produced sudden death without gross pathological damage. Repeated ingestion of small amounts resulted in moderately advanced hardening of the bones. Contact of skin with anhydrous liquid produces severe burns. Inhalation of AHA or aqueous hydrofluoric acid mist or vapors can cause severe respiratory tract irritation that may be fatal. Based on the extreme chemical

  9. Standard test method for the analysis of refrigerant 114, plus other carbon-containing and fluorine-containing compounds in uranium hexafluoride via fourier-transform infrared (FTIR) spectroscopy

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 This test method covers determining the concentrations of refrigerant-114, other carbon-containing and fluorine-containing compounds, hydrocarbons, and partially or completely substituted halohydrocarbons that may be impurities in uranium hexafluoride. The two options are outlined for this test method. They are designated as Part A and Part B. 1.1.1 To provide instructions for performing Fourier-Transform Infrared (FTIR) spectroscopic analysis for the possible presence of Refrigerant-114 impurity in a gaseous sample of uranium hexafluoride, collected in a "2S" container or equivalent at room temperature. The all gas procedure applies to the analysis of possible Refrigerant-114 impurity in uranium hexafluoride, and to the gas manifold system used for FTIR applications. The pressure and temperatures must be controlled to maintain a gaseous sample. The concentration units are in mole percent. This is Part A. 1.2 Part B involves a high pressure liquid sample of uranium hexafluoride. This method can be appli...

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

    International Nuclear Information System (INIS)

    At 11:30 a.m. on January 4, 1986, a Model 48Y UF6 cylinder filled with uranium hexafluoride (UF6) ruptured while it was being heated in a steam chest at the Sequoyah Fuels Conversion Facility near Gore, Oklahoma. One worker died because he inhaled hydrogen fluoride fumes, a reaction product of UF6 and airborne moisture. Several other workers were injured by the fumes, but none seriously. Much of the facility complex and some offsite areas to the south were contaminated with hydrogen fluoride and a second reaction product, uranyl fluoride. The interval of release was approximately 40 minutes. The cylinder, which had been overfilled, ruptured while it was being heated because of the expansion of UF6 as it changed from the solid to the liquid phase. The maximum safe capacity for the cylinder is 27,560 pounds of product. Evidence indicates that it was filled with an amount exceeding this limit. 18 figs

  11. Biological assessment of the effects of construction and operation of a depleted uranium hexafluoride conversion facility at the Paducah, Kentucky, site.

    Energy Technology Data Exchange (ETDEWEB)

    Van Lonkhuyzen, R.

    2005-09-09

    The U.S. Department of Energy (DOE) Depleted Uranium Hexafluoride (DUF{sub 6}) Management Program evaluated alternatives for managing its inventory of DUF{sub 6} and issued the ''Programmatic Environmental Impact Statement for Alternative Strategies for the Long-Term Management and Use of Depleted Uranium Hexafluoride'' (DUF{sub 6} PEIS) in April 1999 (DOE 1999). The DUF{sub 6} inventory is stored in cylinders at three DOE sites: Paducah, Kentucky; Portsmouth, Ohio; and East Tennessee Technology Park (ETTP), near Oak Ridge, Tennessee. In the Record of Decision for the DUF{sub 6} PEIS, DOE stated its decision to promptly convert the DUF6 inventory to a more stable chemical form. Subsequently, the U.S. Congress passed, and the President signed, the ''2002 Supplemental Appropriations Act for Further Recovery from and Response to Terrorist Attacks on the United States'' (Public Law No. 107-206). This law stipulated in part that, within 30 days of enactment, DOE must award a contract for the design, construction, and operation of a DUF{sub 6} conversion plant at the Department's Paducah, Kentucky, and Portsmouth, Ohio, sites, and for the shipment of DUF{sub 6} cylinders stored at ETTP to the Portsmouth site for conversion. This biological assessment (BA) has been prepared by DOE, pursuant to the National Environmental Policy Act of 1969 (NEPA) and the Endangered Species Act of 1974, to evaluate potential impacts to federally listed species from the construction and operation of a conversion facility at the DOE Paducah site.

  12. A study on the reaction of yttria (Y 2O 3) in flowing uranium hexafluoride (UF 6) gas at 900°C

    Science.gov (United States)

    Erkmen, Ziya Engin

    1998-11-01

    The corrosion behaviour of Y 2O 3 (yttria) at 900°C in flowing UF 6 (uranium hexafluoride) was investigated under a pressure of 1.33 × 10 -3 Pa. A test loop was used to study the chemical reaction of sintered and hot-pressed yttria samples with flowing UF 6 gas in an alumina reaction tube installed in an electrically heated horizontal 1200°C type furnace. A weight increase was observed after each exposure testing. Scanning electron microscopy (SEM) examination of the exposed samples identified two layers of reaction products. Significant cracking and porosity were observed in the outer layer after the experiment while the inner layer thickness decreased with increasing the exposure time. Thermodynamical analysis using Facility for the Analysis of Chemical Thermodynamics (FACT) software packages has been performed and relevant interface reactions have been suggested. Pilling-Bedworth Ratios for both layers were calculated and found to be in agreement with the morphology of the layers. Electron microprobe (EMP) and X-ray diffraction analysis (XRD) revealed the formation of UO 2 and YF 3 in the outer layer and a possible formation of YOF in the inner layer. The formation of the outer layer was primarily due to oxygen-fluorine exchange reactions between yttria and uranium fluorides while the inner layer was a direct consequence of the fluorine inward diffusion and reaction with yttria.

  13. Wetland assessment of the effects of construction and operation of a depleted uranium hexafluoride conversion facility at the Portsmouth, Ohio, site

    International Nuclear Information System (INIS)

    The U.S. Department of Energy (DOE) Depleted Uranium Hexafluoride (DUF6) Management Program evaluated alternatives for managing its inventory of DUF6 and issued the ''Programmatic Environmental Impact Statement for Alternative Strategies for the Long-Term Management and Use of Depleted Uranium Hexafluoride'' (DUF6 PEIS) in April 1999 (DOE 1999). The DUF6 inventory is stored in cylinders at three DOE sites: Paducah, Kentucky; Portsmouth, Ohio; and East Tennessee Technology Park (ETTP), near Oak Ridge, Tennessee. In the Record of Decision for the DUF6 PEIS, DOE stated its decision to promptly convert the DUF6 inventory to a more stable chemical form. Subsequently, the U.S. Congress passed, and the President signed, the ''2002 Supplemental Appropriations Act for Further Recovery from and Response to Terrorist Attacks on the United States'' (Public Law No. 107-206). This law stipulated in part that, within 30 days of enactment, DOE must award a contract for the design, construction, and operation of a DUF6 conversion plant at the Department's Paducah, Kentucky, and Portsmouth, Ohio, sites, and for the shipment of DUF6 cylinders stored at ETTP to the Portsmouth site for conversion. This wetland assessment has been prepared by DOE, pursuant to Executive Order 11990 (''Protection of Wetlands'') and DOE regulations for implementing this Executive Order as set forth in Title 10, Part 1022, of the ''Code of Federal Regulations'' (10 CFR Part 1022 [Compliance with Floodplain and Wetland Environmental Review Requirements]), to evaluate potential impacts to wetlands from the construction and operation of a conversion facility at the DOE Portsmouth site. Approximately 0.02 acre (0.009 ha) of a 0.08-acre (0.03-ha) palustrine emergent wetland would likely be eliminated by direct placement of fill material during facility construction at Location A. Portions of this wetland that are not filled may be indirectly affected by an altered hydrologic regime because of the proximity of

  14. Floodplain/wetland assessment of the effects of construction and operation of a depleted uranium hexafluoride conversion facility at the Paducah, Kentucky,site

    International Nuclear Information System (INIS)

    The U.S. Department of Energy (DOE) Depleted Uranium Hexafluoride (DUF6) Management Program evaluated alternatives for managing its inventory of DUF6 and issued the ''Programmatic Environmental Impact Statement for Alternative Strategies for the Long-Term Management and Use of Depleted Uranium Hexafluoride'' (DUF6 PEIS) in April 1999 (DOE 1999). The DUF6 inventory is stored in cylinders at three DOE sites: Paducah, Kentucky; Portsmouth, Ohio; and East Tennessee Technology Park (ETTP), near Oak Ridge, Tennessee. In the Record of Decision for the DUF6 PEIS, DOE stated its decision to promptly convert the DUF6 inventory to a more stable chemical form. Subsequently, the U.S. Congress passed, and the President signed, the ''2002 Supplemental Appropriations Act for Further Recovery from and Response to Terrorist Attacks on the United States'' (Public Law No. 107-206). This law stipulated in part that, within 30 days of enactment, DOE must award a contract for the design, construction, and operation of a DUF6 conversion plant at the Department's Paducah, Kentucky, and Portsmouth, Ohio, sites, and for the shipment of DUF6 cylinders stored at ETTP to the Portsmouth site for conversion. This floodplain/wetland assessment has been prepared by DOE, pursuant to Executive Order 11988 (''Floodplain Management''), Executive Order 11990 (Protection of Wetlands), and DOE regulations for implementing these Executive Orders as set forth in Title 10, Part 1022, of the ''Code of Federal Regulations'' (10 CFR Part 1022 [''Compliance with Floodplain and Wetland Environmental Review Requirements'']), to evaluate potential impacts to floodplains and wetlands from the construction and operation of a conversion facility at the DOE Paducah site. Reconstruction of the bridge crossing Bayou Creek would occur within the Bayou Creek 100-year floodplain. Replacement of bridge components, including the bridge supports, however, would not be expected to result in measurable long-term changes to the

  15. Electronic and vibronic states of uranium hexafluoride in the gas and in the solid phase at very low temperatures

    International Nuclear Information System (INIS)

    Complex vibronic structure has been observed in the electric-dipole-forbidden charge transfer absorption bands of solid and matrix-isolated UF6 in the temperature range 8--14 K. These bands have their maximum intensity near 260 and 375 nm. Associated with the 260 nm band are four electronic transitions with origins at 30 331, 31 032, 32 120, and 32 821 cm/sup -1/, the first two being observed directly. Two more no-phonon transitions are associated with the weak band at 375 nm, one at 24 564 cm/sup -1/ and another at 25 265 cm/sup -1/. These levels are assigned via a weak j-j coupling scheme as excitations from the ligand t/sub u/sigma orbital to empty uranium 5f orbitals. Uranium spin--orbit coupling in UF6 charge transfer states strongly resembles that of UF6-. Several progressions in the symmetric stretch frequency ν1=580--595 cm/sup -1/ are present which have as their origins various combinations of the above electronic levels with the bending modes ν4, ν5, and ν6 or their overtones 2ν4, 2ν5, and 2ν6. Temperature effects, which account for the principal differences between the gas and solid spectra, are also discussed. A much more intense band at 214 nm is lacking in vibronic structure and is attributed to an allowed charge transfer transition

  16. Floodplain/wetland assessment of the effects of construction and operation ofa depleted uranium hexafluoride conversion facility at the Paducah, Kentucky,site.

    Energy Technology Data Exchange (ETDEWEB)

    Van Lonkhuyzen, R.

    2005-09-09

    The U.S. Department of Energy (DOE) Depleted Uranium Hexafluoride (DUF{sub 6}) Management Program evaluated alternatives for managing its inventory of DUF{sub 6} and issued the ''Programmatic Environmental Impact Statement for Alternative Strategies for the Long-Term Management and Use of Depleted Uranium Hexafluoride'' (DUF{sub 6} PEIS) in April 1999 (DOE 1999). The DUF{sub 6} inventory is stored in cylinders at three DOE sites: Paducah, Kentucky; Portsmouth, Ohio; and East Tennessee Technology Park (ETTP), near Oak Ridge, Tennessee. In the Record of Decision for the DUF{sub 6} PEIS, DOE stated its decision to promptly convert the DUF{sub 6} inventory to a more stable chemical form. Subsequently, the U.S. Congress passed, and the President signed, the ''2002 Supplemental Appropriations Act for Further Recovery from and Response to Terrorist Attacks on the United States'' (Public Law No. 107-206). This law stipulated in part that, within 30 days of enactment, DOE must award a contract for the design, construction, and operation of a DUF{sub 6} conversion plant at the Department's Paducah, Kentucky, and Portsmouth, Ohio, sites, and for the shipment of DUF{sub 6} cylinders stored at ETTP to the Portsmouth site for conversion. This floodplain/wetland assessment has been prepared by DOE, pursuant to Executive Order 11988 (''Floodplain Management''), Executive Order 11990 (Protection of Wetlands), and DOE regulations for implementing these Executive Orders as set forth in Title 10, Part 1022, of the ''Code of Federal Regulations'' (10 CFR Part 1022 [''Compliance with Floodplain and Wetland Environmental Review Requirements'']), to evaluate potential impacts to floodplains and wetlands from the construction and operation of a conversion facility at the DOE Paducah site. Reconstruction of the bridge crossing Bayou Creek would occur within the Bayou Creek 100-year

  17. Laser Propagation in Uranium Hexafluoride

    Science.gov (United States)

    Chu, Danny

    1990-01-01

    Several researchers have simulated the laser pulse propagation through simple N-level systems; but, for UF _6 models, large CPU time and memory is required. In an attempt to efficiently yet accurately characterize laser pulse propagation through a UF _6 molecule, a model of UF_6 is created and analyzed by adiabatic excitation. A minimax numerical method is developed to solve the time -dependent Schrodinger equation and then applied to the study of laser excitation of UF_6 using various Gaussian pulses. The process of laser isotope separation is also discussed. The results from the laser excitation of UF_6 are used to simulate laser propagation through ^{235} UF_6.

  18. Rupture of Model 48Y UF6 cylinder and release of uranium hexafluoride. Cylinder overfill, March 12-13, 1986. Investigation of a failed UF6 shipping container. Volume 2

    International Nuclear Information System (INIS)

    NUREG-1179, Volume 1, reported on the rupture of a Model 48Y uranium hexafluoride (UF6) cylinder and the subsequent release of UF6. At the time of publication, a detailed metallurgical examination of the damaged cylinder was under way and results were not available. Subsequent to the publication of Volume 1, a second incident occurred at the Sequoyah Fuels Corporation facility. On March 13, 1986, a Model 48X cylinder was overfilled during a special one-time draining procedure; however, no release of UF6 occurred. An Augmented Investigation Team investigated this second incident. This report, NUREG-1179, Volume 2, presents the findings made by the Augmented Investigation Team of the March 13 incident and the report of the detailed metallurgical examination conducted by Battelle Columbus Division of the cylinder damaged on January 4, 1986

  19. Surface decontamination in the old storage shed number 99 of the General Plan of IPEN/CNEN-SP, containing production equipment of natural uranium hexafluoride (UF6), aiming at its decommissioning

    International Nuclear Information System (INIS)

    This paper presents the steps adopted in the operation planned for the decontamination of surfaces in the old storage shed number 99 the general layout of the Energy Research and Nuclear IPEN-CNEN/SP, Brazil, and contained various types of equipment originating from production hexafluoride natural uranium (UF6). This operation involved the planning, training of operators of the facility, analysis of workplaces and radiometric surveys for monitoring of external radiation and surface contamination. The training involved the procedures for decontamination of surfaces, segregation of materials and practical procedures for individual monitoring of contamination outside of the body. Were also established rules for the transport of radioactive materials in the internal and external facility and release of material and sites already decontaminated

  20. 77 FR 1059 - Low Enriched Uranium From France: Initiation of Antidumping Duty Changed Circumstances Review

    Science.gov (United States)

    2012-01-09

    ... enriched uranium hexafluoride (UF 6 ) with a U\\235\\ product assay of less than 20 percent that has not been... cover enriched uranium hexafluoride with a U\\235\\ assay of 20 percent or greater, also known as highly... greater than 0.711 percent and natural uranium concentrates converted into uranium hexafluoride with a...

  1. Correlation of radioactive-waste-treatment costs and the environmental impact of waste effluents in the nuclear fuel cycle: conversion of yellow cake to uranium hexafluoride. Part II. The solvent extraction-fluorination process

    International Nuclear Information System (INIS)

    A cost/benefit study was made to determine the cost and effectiveness of radioactive waste (radwaste) treatment systems for decreasing the release of radioactive materials and chemicals from a model uranium hexafluoride (UF6) production plant using the solvent extraction-fluorination process, and to evaluate the radiological impact (dose commitment) of the release materials on the environment. The model plant processes 10,000 metric tons of uranium per year. Base-case waste treatment is the minimum necessary to operate the process. Effluents meet the radiological requirements listed in the Code of Federal Regulations, Title 10, Part 20 (10 CFR 20), Appendix B, Table II, but may not be acceptable chemically at all sites. Additional radwaste treatment techniques are applied to the base-case plant in a series of case studies to decrease the amounts of radioactive materials released and to reduce the amounts of radioactive materials released and to reduce the radiological dose commitment to the population in the surrounding area. The costs for the added waste treatment operations and the corresponding dose committment are correlated with the annual cost for treatment of the radwastes. The status of the radwaste treatment methods used in the case studies is discussed. Much of the technology used in the advanced cases will require development and demonstration, or else is proprietary and unavailable for immediate use. The methodology and assumptions for the radiological doses are found in ORNL-4992

  2. Correlation of radioactive-waste-treatment costs and the environmental impact of waste effluents in the nuclear fuel cycle: conversion of yellow cake to uranium hexafluoride. Part II. The solvent extraction-fluorination process

    Energy Technology Data Exchange (ETDEWEB)

    Sears, M.B.; Etnier, E.L.; Hill, G.S.; Patton, B.D.; Witherspoon, J.P.; Yen, S.N.

    1983-03-01

    A cost/benefit study was made to determine the cost and effectiveness of radioactive waste (radwaste) treatment systems for decreasing the release of radioactive materials and chemicals from a model uranium hexafluoride (UF/sub 6/) production plant using the solvent extraction-fluorination process, and to evaluate the radiological impact (dose commitment) of the release materials on the environment. The model plant processes 10,000 metric tons of uranium per year. Base-case waste treatment is the minimum necessary to operate the process. Effluents meet the radiological requirements listed in the Code of Federal Regulations, Title 10, Part 20 (10 CFR 20), Appendix B, Table II, but may not be acceptable chemically at all sites. Additional radwaste treatment techniques are applied to the base-case plant in a series of case studies to decrease the amounts of radioactive materials released and to reduce the amounts of radioactive materials released and to reduce the radiological dose commitment to the population in the surrounding area. The costs for the added waste treatment operations and the corresponding dose committment are correlated with the annual cost for treatment of the radwastes. The status of the radwaste treatment methods used in the case studies is discussed. Much of the technology used in the advanced cases will require development and demonstration, or else is proprietary and unavailable for immediate use. The methodology and assumptions for the radiological doses are found in ORNL-4992.

  3. Correlation of radioactive waste treatment costs and the environmental impact of waste effluents in the nuclear fuel cycle: conversion of yellow cake to uranium hexafluoride. Part I. The fluorination-fractionation process

    International Nuclear Information System (INIS)

    A cost/benefit study was made to determine the cost and effectiveness of radioactive waste (radwaste) treatment systems for decreasing the release of radioactive materials and chemicals from a model uranium hexafluoride (UF6) production plant using the fluorination-fractionation (dry hydrofluor) process, and to evaluate the radiological impact (dose commitment) of the released materials on the environment. This study is designed to assist in defining the term as low as is reasonably achievable (ALARA) in relation to limiting the release of radioactive materials from nuclear facilities. The model plant processes 10,000 metric tons of uranium per year. Base-case waste treatment is the minimum necessary to operate the process. Effluents meet the radiological requirements listed in the Code of Federal Regulations, Title 10, Part 20 (10 CFR 20), Appendix B, Table II, but may not be acceptable chemically at all sites. Additional radwaste treatment techniques are applied to the base-case plant in a series of case studies to decrease the amounts of radioactive materials released and to reduce the radiological dose commitment to the population in the surrounding area. The costs for the added waste treatment operations and the corresponding dose commitment are calculated for each case. In the final analysis, radiological dose is plotted vs the annual cost for treatment of the radwastes. The status of the radwaste treatment methods used in the case studies is discussed. Much of the technology used in the advanced cases will require development and demonstration or else is proprietary and unavailable for immediate use. The methodology and assumptions for the radiological doses are found in ORNL-4992

  4. Correlation of radioactive waste treatment costs and the environmental impact of waste effluents in the nuclear fuel cycle: conversion of yellow cake to uranium hexafluoride. Part I. The fluorination-fractionation process

    Energy Technology Data Exchange (ETDEWEB)

    Sears, M.B.; Blanco, R.E.; Finney, B.C.; Hill, G.S.; Moore, R.E.; Witherspoon, J.P.

    1977-07-01

    A cost/benefit study was made to determine the cost and effectiveness of radioactive waste (radwaste) treatment systems for decreasing the release of radioactive materials and chemicals from a model uranium hexafluoride (UF/sub 6/) production plant using the fluorination-fractionation (dry hydrofluor) process, and to evaluate the radiological impact (dose commitment) of the released materials on the environment. This study is designed to assist in defining the term as low as is reasonably achievable (ALARA) in relation to limiting the release of radioactive materials from nuclear facilities. The model plant processes 10,000 metric tons of uranium per year. Base-case waste treatment is the minimum necessary to operate the process. Effluents meet the radiological requirements listed in the Code of Federal Regulations, Title 10, Part 20 (10 CFR 20), Appendix B, Table II, but may not be acceptable chemically at all sites. Additional radwaste treatment techniques are applied to the base-case plant in a series of case studies to decrease the amounts of radioactive materials released and to reduce the radiological dose commitment to the population in the surrounding area. The costs for the added waste treatment operations and the corresponding dose commitment are calculated for each case. In the final analysis, radiological dose is plotted vs the annual cost for treatment of the radwastes. The status of the radwaste treatment methods used in the case studies is discussed. Much of the technology used in the advanced cases will require development and demonstration or else is proprietary and unavailable for immediate use. The methodology and assumptions for the radiological doses are found in ORNL-4992.

  5. Uranium conversion

    International Nuclear Information System (INIS)

    FOI, has performed a study on uranium conversion processes that are of importance in the production of different uranium compounds in the nuclear industry. The same conversion processes are of interest both when production of nuclear fuel and production of fissile material for nuclear weapons are considered. Countries that have nuclear weapons ambitions, with the intention to produce highly enriched uranium for weapons purposes, need some degree of uranium conversion capability depending on the uranium feed material available. This report describes the processes that are needed from uranium mining and milling to the different conversion processes for converting uranium ore concentrate to uranium hexafluoride. Uranium hexafluoride is the uranium compound used in most enrichment facilities. The processes needed to produce uranium dioxide for use in nuclear fuel and the processes needed to convert different uranium compounds to uranium metal - the form of uranium that is used in a nuclear weapon - are also presented. The production of uranium ore concentrate from uranium ore is included since uranium ore concentrate is the feed material required for a uranium conversion facility. Both the chemistry and principles or the different uranium conversion processes and the equipment needed in the processes are described. Since most of the equipment that is used in a uranium conversion facility is similar to that used in conventional chemical industry, it is difficult to determine if certain equipment is considered for uranium conversion or not. However, the chemical conversion processes where UF6 and UF4 are present require equipment that is made of corrosion resistant material

  6. 49 CFR 173.477 - Approval of packagings containing greater than 0.1 kg of non-fissile or fissile-excepted uranium...

    Science.gov (United States)

    2010-10-01

    ... kg of non-fissile or fissile-excepted uranium hexafluoride. 173.477 Section 173.477 Transportation... non-fissile or fissile-excepted uranium hexafluoride. (a) Each offeror of a package containing more than 0.1 kg of uranium hexafluoride must maintain on file for at least one year after the...

  7. Production of sized particles of uranium oxides and uranium oxyfluorides

    International Nuclear Information System (INIS)

    A process for converting uranium hexafluoride to uranium dioxide of a relatively large particle size in a fluidized bed reactor by mixing uranium hexafluoride with a mixture of steam and hydrogen to form a mixture of uranium oxide and uranium oxyfluoride seed particles of varying sizes, separating the larger particles from the smaller particles in a cyclone separator, recycling the smaller seed particles through the ejector to increase their size, and introducing the larger seed particles from the cyclone separator into a fluidized bed reactor where the seed particles serve as nuclei on which coarser particles of uranium dioxide are formed. (Patent Office Record)

  8. 78 FR 66898 - Low Enriched Uranium From France: Final Results of Changed Circumstances Review

    Science.gov (United States)

    2013-11-07

    ..., and Preliminary Results of Changed Circumstances Review, 78 FR 52905 (August 27, 2013) (Preliminary... uranium. Low- enriched uranium is enriched uranium hexafluoride (UF 6 ) with a U\\235\\ product assay of... outside the scope of the order. Specifically, the order does not cover enriched uranium hexafluoride...

  9. Uranium

    International Nuclear Information System (INIS)

    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.

  10. Production of sized particles of uranium oxides and uranium oxyfluorides

    International Nuclear Information System (INIS)

    A process is claimed for converting uranium hexafluoride (UF6) to uranium dioxide (UO2) of a relatively large particle size in a fluidized bed reactor by mixing uranium hexafluoride with a mixture of steam and hydrogen and by preliminary reacting in an ejector gaseous uranium hexafluoride with steam and hydrogen to form a mixture of uranium and oxide and uranium oxyfluoride seed particles of varying sizes, separating the larger particles from the smaller particles in a cyclone separator, recycling the smaller seed particles through the ejector to increase their size, and introducing the larger seed particles from the cyclone separator into a fluidized bed reactor where the seed particles serve as nuclei on which coarser particles of uranium dioxide are formed. 9 claims, 2 drawing figures

  11. NF ISO 7097-1. Nuclear fuel technology - Uranium dosimetry in solutions, in uranium hexafluoride and in solids - Part 1: reduction with iron (II) / oxidation with potassium bi-chromate / titration method

    International Nuclear Information System (INIS)

    This standard document describes the mode of operation of three different methods for the quantitative dosimetry of uranium in solutions, in UF6 and in solids: reduction by iron (II), oxidation by potassium bi-chromate and titration. (J.S.)

  12. Eldorado plans second uranium refinery

    International Nuclear Information System (INIS)

    Eldorado Nuclear Ltd. intends to open a new uranium refinery at Port Granby, Ont., by 1980, thereby tripling output of uranium hexafluoride. In the 1980's, the company plans to build a third refinery in Saskatchewan. The process of producing uranium hexafluoride from crude yellowcake is explained, and improvements introduced by Eldorado are discussed. They include a continuous denitrator for producing uranium trioxide, and 'pillow block' briquetting rollers for briquetting it before it is reduced with hydrogen to uranium dioxide. (N.D.H.)

  13. World uranium production outlook

    International Nuclear Information System (INIS)

    An outlook on the uranium trade (concentrate and hexafluoride) between the Western world and the the former Comecon countries. The flow from East to West is increased. Up to 1998 existing lower-cost reserves appear to supply enough uranium. Later, the supply gap will require greater output from development of known reserves at costs higher than $30/lb. 4 figs., 1 ref

  14. Physical analytical methods for uranium hexafluoride

    International Nuclear Information System (INIS)

    Various physical methods of analysis currently used or still under investigation such as: sound analysis, vapor pressure measurements, fractional distillation, cryogenics, micro-sublimation, ultra-violet, visible and infra-red absorption spectrophotometry, nuclear magnetic resonance and mass spectrometry are reviewed. For each method, principle and applications are given, and results obtained concerning reproducibility, application limits and rapidity are discussed. (author)

  15. Uranium hexafluoride container design no. 0236

    International Nuclear Information System (INIS)

    The specification covers the construction of the mild steel container complete with cover, sealing ring, sealing plug and with mild steel skirt and lifting lug welded on as shown. It specifies in detail only those factors essential to the maintenance of interchangeability on the plant between containers supplied by different manufacturers. (U.K.)

  16. Update on packaging for uranium hexafluoride transport

    International Nuclear Information System (INIS)

    The slightly enriched product UF6 shipped from the enriching plants for the world's nuclear power plants must be protected in order to conform to domestic and international transport regulations. The principal overpack currently in use is the U.S. Department of Transportation (DOT) Specification 21PF-1 which protects Model 30 UF6 cylinders (Title 49, Code of Federal Regulations; Part 178.121, Specification 21PF-1; Fire and Shock Resistant, Phenolic - Foam Insulated Overpack [Horizontal Loading]). Operational problems have developed due both to design and lack of maintenance, resulting in the entry of water into the insulation zone. Following major review of these problems, particularly those concerned with water entry and general deterioration, design modifications for have been proposed. These modifications for existing overpacks are to be made only after any water absorbed within the phenolic foam insulation is reduced to an acceptable level. New overpacks will be fabricated under an enhanced design. Existing overpacks which are modified will be designated as 21PF-1A while new overpacks fabricated to the enhance design will be designated as 21PF-1B. In both cases, proposed quality assurance/control requirements in the fabrication, modification, use and maintenance of the overpacks are applicable to fabricators, modifiers, owners and users. A composite report describing the proposal has been prepared

  17. Development of packaging for enriched uranium hexafluoride

    International Nuclear Information System (INIS)

    The new PSP developed by Mitsubishi Materials Corporation has been confirmed to meet the Type F and/or B(M) requirements prescribed in the revised IAEA Regulations for the Safe Transport of Radioactive Materials (1996 Edition). The combination of the valve pocket and the cylinder-rotation stopper worked well to protect the valve of the cylinder. Since we found out through the test that the cylinder can easily rotates within the overpack by the shock of the drop tests, the 'cylinder-rotation stopper' was essential to make the valve pocket work properly. In addition, the special ring also worked well to minimize the deformation of the cylinder skirt. Polyurethane foam showed itself to be a good mechanical shock absorber and a thermal insulator through the tests. Furthermore the PSP demonstrated good handling performance and good quality assurance by eliminating wooden materials. Currently, an approval for the design from the Japanese competent authority is being examined. After obtaining Japanese approval, a multilateral approval will be applied successively. (authors)

  18. Reaction of uranium hexafluoride with fluoroelastomers

    International Nuclear Information System (INIS)

    All investigations were made in a stainless steel reaction vessel which was designed to serve also as a gas cell. By infrared spectroscopy of the gas phase it can be shown that traces of hydrogen fluoride present in technical grade UF6 penetrate into the fluoroelastomer material where they react with the metallic compounds forming water. This water diffuses through the sealing material and causes subsequently a hydrolysis process of UF6 in the gas phase. Gaseous HF is produced and acts as a fluorine transmitter between UF6 and the metallic compounds. These solid products formed by UF6 hydrolysis are deposited in the vicinity of the fluoroelastomers. (orig./PW)

  19. Effects of collisions on uranium hexafluoride fluorescence

    Science.gov (United States)

    Menghini, M.; Montone, A.; Morales, P.; Nencini, L.; Dore, P.

    1988-09-01

    Laser-induced fluorescence intensities and quenching are used to probe collisional relaxation of UF 6. Buffer gases used are rare gases, N 2, O 2, CO 2, N 2O, SO 2, SiF 4 and SF 6. Energy transfer associated with anisotropic interactions is important in determining the UF 6 fluorescence quenching.

  20. Reactions of uranium hexafluoride photolysis products

    Science.gov (United States)

    Lyman, John L.; Laguna, Glenn; Greiner, N. R.

    1985-01-01

    This paper confirms that the ultraviolet photolysis reactions of UF6 in the B band spectral region is simple bond cleavage to UF5 and F. The photolysis products may either recombine to UF6 or the UF5 may dimerize, and ultimately polymerize, to solid UF5 particles. We use four methods to set an upper limit for the rate constant for recombination of kr<2.0×10-12cm3 molecule-1 s-1. We measure the rate constant for UF5 dimerization to be kd=(1.0±0.2)×10-11 cm3 molecule-1 s-1. The principal method employed in these studies is the use of diode lasers to monitor, in real time, the changes in density of the species UF6 and UF5 after laser photolysis of the UF6 gas sample.

  1. Uranium

    International Nuclear Information System (INIS)

    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. Uranium

    International Nuclear Information System (INIS)

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

  3. Uranium

    International Nuclear Information System (INIS)

    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

  4. Uranium

    International Nuclear Information System (INIS)

    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.)

  5. Uranium

    International Nuclear Information System (INIS)

    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

  6. Sulphur hexafluoride as a stripper gas for tandem accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Hotchkis, M.A.C., E-mail: mah@ansto.gov.au; Child, D.; Fink, D.; Garton, D.; Levchenko, V.; Wilcken, K.

    2013-05-01

    Highlights: •Sulphur hexafluoride is investigated as a stripper gas in tandem accelerators. •For heavy ions at low terminal voltage, mean charge states are found to be up to 1 charge unit higher than with argon gas. •Charge state distributions are found to be broader than with argon gas. •For charge states above the mean charge state, yields are typically doubled using SF{sub 6}. •Using SF{sub 6} stripper gas, the efficiency of actinides AMS analysis is doubled. -- Abstract: We have investigated sulphur hexafluoride as a stripper gas in tandem accelerators by using the ANTARES accelerator system at ANSTO to measure charge state distributions for this gas. Results are reported at 4 MV terminal voltage for injected negative ions ranging from carbon to uranium oxide. For iodine and thorium the distributions are extended across a range of energies of practical use for accelerator mass spectrometry, ion beam analysis and other accelerator applications. Charge state distributions using sulphur hexafluoride are found to have mean charge states up to 1 charge unit higher than, and to be broader than, corresponding distributions for argon gas, except in the case of carbon beams. As a result, SF{sub 6} is shown to provide significantly higher yields for charge states of heavy ions above the mean charge state. We now perform actinide AMS measurements with 9% yield to the 5+ charge state, compared to 4–5% achieved previously with argon gas.

  7. Uranium. Suppl. Vol. A3

    International Nuclear Information System (INIS)

    This supplement volume 'Uranium' deals with uranium technology, from winning to the fabrication of nuclear fuels containing uranium and their use in various reactor types. Alternative reprocessing methods for ores are described e.g. winning from phosphate ores and sea water, production of uranium compounds (oxide, carbide, nitride etc., hexafluoride for isotope separation) and of uranium-metals and -alloys as well as the utilization of metallic and other compounds of uranium - single or embedded - as nuclear fuels and their fabrication. The behaviour of the nuclear fuel and the way it modifies during reactor operation are described in an extra volume (supplement volume A4). (RB)

  8. Uranium

    International Nuclear Information System (INIS)

    Canada produced one-third of the Western World's uranium production in 1989, twice as much from Saskatchewan as from Ontario, where mine closures have led to the loss of over 2,000 jobs. Canadian production in 1990 was about 8.8 Gg U. In 1990, Canada's primary producers were Denison Mines, Rio Algom, Cluff Mining, and Cameco. In Saskatchewan, there are three operations: Key Lake, Rabbit Lake/Collins Bay, and Cluff Lake. Canada stands fourth in uranium resources, but because of favourable geology remains the focus of much exploration activity, which cost about C$60 in 1989. Large stockpiles overhang the market, so new sources of uranium will not be needed before the mid 1990's, but long-term prospects seem good

  9. Uranium

    International Nuclear Information System (INIS)

    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 U3O8; 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

  10. The current status of decommissioning on the JAEA's uranium conversion facilities at Ningyo-toge Center

    International Nuclear Information System (INIS)

    The refining and conversion facilities at the Ningyo-toge site of JAEA (Japan Atomic Energy Agency), was started in the uranium conversion operation with both yellow cake as natural uranium and uranium trioxide as reprocessed uranium in 1983. These facilities produced about 385 tU of natural uranium hexafluoride (NUF6) and about 350 tU of reprocessed uranium hexafluoride (ReUF6) until December 1999. The decommissioning of the facilities started according to the regulatory procedure. In this paper, we describe the outline of the results on dismantling of the natural uranium facilities, the project and progress on the reprocessed uranium conversion facilities. (author)

  11. The Globe laid bare

    CERN Multimedia

    Fortunati, Lucien

    2015-01-01

    If you’re at CERN at the moment, you will certainly have noticed the work under way on the Globe. The structure, which has been in pride of place opposite the Laboratory for over ten years, has never been so completely laid bare. But, as we explained in a previous article (see here), it is all for a good cause. The Globe is built entirely from wood and certain parts of it need to be replaced.

  12. Uranium recovery from slags of metallic uranium

    International Nuclear Information System (INIS)

    The Center of the Nuclear Fuel of the Institute of Nuclear Energy Research - IPEN finished the program of attainment of fuel development for research reactors the base of Uranium Scilicet (U3 Si2) from Hexafluoride of Uranium (UF6) with enrichment 20% in weight of 235U. In the process of attainment of the league of U 3 Si 2 we have as Uranium intermediate product the metallic one whose attainment generates a slag contend Uranium. The present work shows the results gotten in the process of recovery of Uranium in slags of calcined slags of Uranium metallic. Uranium the metallic one is unstable, pyrophoricity and extremely reactive, whereas the U3O8 is a steady oxide of low chemical reactivity, what it justifies the process of calcination of slags of Uranium metallic. The calcination of the Uranium slag of the metallic one in oxygen presence reduces Uranium metallic the U3O8. Experiments had been developed varying it of acid for Uranium control and excess, nitric molar concentration gram with regard to the stoichiometric leaching reaction of temperature of the leaching process. The 96,0% income proves the viability of the recovery process of slags of Uranium metallic, adopting it previous calcination of these slags in nitric way with low acid concentration and low temperature of leaching. (author)

  13. Surface decontamination in the old storage shed number 99 of the General Plan of IPEN/CNEN-SP, containing production equipment of natural uranium hexafluoride (UF{sub 6}), aiming at its decommissioning; Descontaminacao de superficies no antigo galpao de estocagem numero 99 da planta geral do IPEN/CNEN-SP, contendo equipamentos da producao de hexafluoreto de uranio natural, (UF{sub 6}), visando seu descomissionamento

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Claudio C. de; Cambises, Paulo B.S.; Paiva, Julio E. de; Paiva, Julio E. de; Silva, Teresina M.; Rodrigues, Demerval L., E-mail: calmeida@ipen.br, E-mail: cambises@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    2013-11-01

    This paper presents the steps adopted in the operation planned for the decontamination of surfaces in the old storage shed number 99 the general layout of the Energy Research and Nuclear IPEN-CNEN/SP, Brazil, and contained various types of equipment originating from production hexafluoride natural uranium (UF6). This operation involved the planning, training of operators of the facility, analysis of workplaces and radiometric surveys for monitoring of external radiation and surface contamination. The training involved the procedures for decontamination of surfaces, segregation of materials and practical procedures for individual monitoring of contamination outside of the body. Were also established rules for the transport of radioactive materials in the internal and external facility and release of material and sites already decontaminated.

  14. Depleted uranium management alternatives

    International Nuclear Information System (INIS)

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

  15. United Kingdom experience of uranium tetrafluoride production

    International Nuclear Information System (INIS)

    Uranium tetrafluoride, the key intermediate in the production of uranium hexafluoride and uranium metal, has been produced for more than 35 years at the Springfields Works of British Nuclear Fuels Limited. A brief summary of the background history of UF4 production at Springfields is given, together with a description of the present manufacturing route employing rotary kilns. Comments are included on some safety issues involved

  16. The Globe laid bare

    CERN Multimedia

    Anaïs Schaeffer

    2015-01-01

    If you’re at CERN at the moment, you will certainly have noticed the work under way on the Globe. The structure, which has been in pride of place opposite the Laboratory for over ten years, has never been so completely laid bare. But, as we explained in a previous article (see here), it is all for a good cause. The Globe is built entirely from wood and certain parts of it need to be replaced.   The Globe after the removal of all the sun baffles. Image: Lucien Fortunati. Picture the general structure of the Globe. In simple terms, the building consists of two spheres, one inside the other. The inner sphere houses the Universe of Particles exhibition and the conference room and is connected to the outer sphere by two access ramps. “Each of these two spheres is made up of eighteen large supporting arcs,” explains Amaya Martínez García of the GS department, who is supervising the Globe renovation project. “These eighteen arcs are ...

  17. Helium and Sulfur Hexafluoride in Musical Instruments

    Science.gov (United States)

    Forinash, Kyle; Dixon, Cory L.

    2014-01-01

    The effects of inhaled helium on the human voice were investigated in a recent article in "The Physics Teacher." As mentioned in that article, demonstrations of the effect are a popular classroom activity. If the number of YouTube videos is any indication, the effects of sulfur hexafluoride on the human voice are equally popular.…

  18. A Relativistic Density Functional Study on the Uranium Hexafluoride and Plutonium Hexafluoride Monomer and Dimer Species

    OpenAIRE

    Gagliardi, Laura; Willetts, Andrew; Skylaris, Chris-Kriton; Handy, Nicholas C.; Spencer, Steven; Ioannou, Andrew G.; Simper, Adrian M.

    1998-01-01

    A study on the UF6 monomer and dimer was carried out within the density functional method. The U−F distance in the UF6 monomer was optimized at different levels of theory, pointwise, assuming octahedral geometry, (1) by using an all-electron basis for both U and F in a nonrelativistic calculation; (2) by using a relativistic effective core potential (RECP) on U and nonrelativistic effective core potential (ECP) on the fluorines; and (3) by using RECP on the U atom and an all-electron basis on...

  19. Observation of the uranium 235 nuclear magnetic resonance signal

    OpenAIRE

    Le Bail, H.; Chachaty, C.; Rigny, P.; Bougon, R.

    1983-01-01

    The first observation of the nuclear magnetic resonance of the uranium 235 is reported. It has been performed on pure liquid uranium hexafluoride at 380 K. The measured magnetogyric ratio is | γ(235U) | = 492.6 ± 0.2 rad.s-1 G-1.

  20. 75 FR 44817 - Notice of Availability of Uranium Enrichment Fuel Cycle Facility Inspection Reports Regarding...

    Science.gov (United States)

    2010-07-29

    ... amended. The introduction of uranium hexafluoride into any module of the National Enrichment Facility is... COMMISSION Notice of Availability of Uranium Enrichment Fuel Cycle Facility Inspection Reports Regarding...: Ty Naquin, Project Manager, Uranium Enrichment Branch, Division of Fuel Cycle Safety and...

  1. 76 FR 67765 - Notice of Availability of Uranium Enrichment Fuel Cycle Facility's Inspection Reports Regarding...

    Science.gov (United States)

    2011-11-02

    ... Energy Act of 1954, as amended. The introduction of uranium hexafluoride into any module of the National... COMMISSION Notice of Availability of Uranium Enrichment Fuel Cycle Facility's Inspection Reports Regarding... CONTACT: Gregory Chapman, Project Manager, Uranium Enrichment Branch, Division of Fuel Cycle Safety...

  2. 77 FR 65729 - Uranium Enrichment Fuel Cycle Facility Inspection Reports Regarding Louisiana Energy Services LLC...

    Science.gov (United States)

    2012-10-30

    ... Act of 1954, as amended. The introduction of uranium hexafluoride into any module of the National... COMMISSION Uranium Enrichment Fuel Cycle Facility Inspection Reports Regarding Louisiana Energy Services LLC... Regulatory Commission Brian W. Smith, Chief, Uranium Enrichment Branch, Division of Fuel Cycle Safety...

  3. 78 FR 23312 - Uranium Enrichment Fuel Cycle Inspection Reports Regarding Louisiana Energy Services, National...

    Science.gov (United States)

    2013-04-18

    ... introduction of uranium hexafluoride (UF 6 ) into cascades numbered 2.9, 2.10, 2.11, 2.12, 3.1, 3.2, 3.3, 3.4... COMMISSION Uranium Enrichment Fuel Cycle Inspection Reports Regarding Louisiana Energy Services, National..., Uranium Enrichment Branch, Division of Fuel Cycle Safety, and Safeguards Office of Nuclear Material...

  4. 77 FR 18272 - Uranium Enrichment Fuel Cycle Facility Inspection Reports Regarding Louisiana Energy Services LLC...

    Science.gov (United States)

    2012-03-27

    ... 1954, as amended. The introduction of uranium hexafluoride into any module of the National Enrichment... COMMISSION Uranium Enrichment Fuel Cycle Facility Inspection Reports Regarding Louisiana Energy Services LLC.... Brian W. Smith, Chief, Uranium Enrichment Branch, Division of Fuel Cycle Safety and Safeguards,...

  5. 10 CFR 51.51 - Uranium fuel cycle environmental data-Table S-3.

    Science.gov (United States)

    2010-01-01

    ... uranium mining and milling, the production of uranium hexafluoride, isotopic enrichment, fuel fabrication... 10 percent of 10 CFR 20 for total processing 26 annual fuel requirements for model LWR. Fission and... 10 Energy 2 2010-01-01 2010-01-01 false Uranium fuel cycle environmental data-Table S-3....

  6. 77 FR 19642 - Low Enriched Uranium From France: Final Results of Antidumping Duty Changed Circumstances Review

    Science.gov (United States)

    2012-04-02

    ... Uranium From France, 67 FR 6680 (February 13, 2002). As for evaluating AREVA's request, the Department... Circumstances Review, 77 FR 7128 (February 10, 2012) (Preliminary Results). DATES: Effective Date: April 2, 2012... product covered by the order is all low enriched uranium (LEU). LEU is enriched uranium hexafluoride (UF...

  7. 77 FR 7128 - Low Enriched Uranium From France: Preliminary Results of Antidumping Duty Changed Circumstances...

    Science.gov (United States)

    2012-02-10

    ... Determination and Notice of Countervailing Duty Order: Low Enriched Uranium From France, 67 FR 6689 (February 13..., 77 FR 1059 (January 9, 2012) (CCR Initiation Notice). DATES: Effective Date: February 10, 2012. FOR... uranium (LEU). LEU is enriched uranium hexafluoride (UF 6 ) with a U\\235\\ product assay of less than...

  8. Solid Bare Strange Quark Stars

    CERN Document Server

    Xu, R X

    2003-01-01

    The reason, we need three terms of `strange', `bare', and `solid' before quark stars, is presented concisely though some fundamental issues are not certain. Observations favoring these stars are introduced.

  9. Perspectives of Siberian chemical plant in increasing volumes of uranium concentrates recycling

    OpenAIRE

    Lazarchuk, V. V.; Shikerun, T. G.; Ryabov, A. S.; Shamin, V. I.; Zhiganov, A. N.

    2007-01-01

    The purification technology of uranium concentrate of natural isotopic composition developed at Siberian chemical enterprise is basically universal, allows recycling uranium concentrates with different content of impurities and obtaining uranium nitrate solutions corresponding by quality to the international standards requirements to uranium hexafluoride preparation for isotopes ASTM C 787-03 separation and to ceramic fuel ASTM C 788-02 preparation. Uranium reserves in Russia and abroad were ...

  10. Sulfur hexafluoride - A powerful new atmospheric tracer

    OpenAIRE

    Maiss, Manfred; Steele, Paul; Francey, Roger; Fraser, Paul; Langenfelds, Ray; Trivett, Neil; Levin, Ingeborg

    1996-01-01

    Long-term observations of the atmospheric trace gas sulfur hexafluoride (SF6) at four background monitoring stations, Neumayer, Antarctica (1986-1994), Cape Grim, Tasmania (1978-1994), Izana, Canary Islands (1991-1994) and Alert, Canada (1993-1994) are presented. These data sets are supplemented by two meridional profiles collected over the Atlantic Ocean (1990 and 1993) and occasional observations at the regional site Fraserdale, Canada (1994). The analytical system and the method of SF6 cal...

  11. Recent measurements concerning uranium hexafluoride-electron collision processes

    International Nuclear Information System (INIS)

    Scattering of electrons by UF6 molecule was studied at impact energies ranging from 5 to 100 eV and momentum transfer, elastic and inelastic scattering cross sections were determined. The measurements also yielded spectroscopic information which made possible to extend the optical absorption cross sections from 2000 to 435A. It was found that UF6 is a very strong absorber in the vacuum UV region. No transitions were found to lie below the onset of the optically detected 3.0 eV feature

  12. Evaluation of safety in the transportation of natural uranium hexafluoride

    International Nuclear Information System (INIS)

    A general model developed for the safety of transporting radioactive materials is applied to UF6. Results given concern only the container contents during an accident; harmful consequences to the environment are not considered. It is shown that railroad transport is safer than road transport, particularly with regard to fire. 13 figs., 12 tables

  13. Risks of shippng uranium hexafluoride by truck and train

    International Nuclear Information System (INIS)

    Risk is defined as the product of the probability of a release of material to the environment and the consequences resulting from the release. Although a few accidents involving UF6 containers have occurred during transportation, they are insufficient in number and consequences to provide data for a risk assessment of UF6 transport. For this reason, this study used the predictive risk assessment methodology developed in the Transportation Safety Studies Project. The methodology is composed of four basic steps: detailed description of the transportation system, identification of possible material release sequences, evaluation of the probabilities and the consequences of the releases, and calculation and assessment of the risk. The system description includes projected industry characteristics, amounts to be shipped and the number of shipments required, material characteristics, transport mode and carrier., container types, routes (and any restrictions), and weather and population zones. Release sequences are identified using fault tree analyses. Releases are evaluated using container failure data and mathematical models for dispersion and health effects. The risk is then calculated and compared to other known risks. Only releases resulting from transportation accidents or nonstandard container closures (or combinations of both) were considered. 5 figures, 2 tables

  14. Bursting tests on type 48Y containers for uranium hexafluoride

    International Nuclear Information System (INIS)

    In order to conform to the new requirements from the IAEA, it is necessary for the large-scale UF6 containers to comply with the fire resistance requirement imposed for type B packages. The thermohydraulic characteristics of UF6, which now are defined, and the calculation models, which are validated, have revealed major risks of rupture of the container. The purpose of the present programme is to define the strength limits of the materials at the moment of rupture of the wall under the conditions of the fire test. Three industrial containers, of different grades, are heated after being previously equipped and insulated, and are pressurised by the injection of nitrogen until rupture takes place. Two of the containers are filled with dry sand. After preliminary tests performed to validate the measurement chains and the data acquisition system, the 3 tests are carried out in a large open area which affords the required safety against the effects of the bursting of the cylinder. (authors)

  15. Recommendations for providing protection during the transport of uranium hexafluoride

    International Nuclear Information System (INIS)

    In July 1986 a group of consultants was convened by the IAEA to provide initial guidance on the transport of UF6 and the regulations for it considering the hazards posed by this material. A Technical Committee meeting was held in November 1986 to finalize the development of the recommendations for providing protection during the transport of UF6. This report provides the recommendations resulting from the meetings of these experts. The IAEA recommends that national competent authorities and other relevant national regulatory and standards-related organizations, and appropriate international organizations seriously consider all of the information provided in this report especially the additional requirements set forth in Section III.3 concerning design, manufacturing and testing requirements, design approval requirements, requirements on loading for transport, and requirements for quality assurance and maintenance. This report also deals with United Nations' Recommendations of the Transport of Dangerous Goods, International Modal Regulatory Documents, ANSIN14.1-1982 and ISO/DIS/7195 Standards

  16. The emission characteristics of uranium hexafluoride at high temperatures

    Science.gov (United States)

    Krascella, N. L.

    1976-01-01

    Relative emission measurements were made for UF6/Argon mixtures heated in a plasma torch over a range of temperatures from 800 to about 3600 K over a wavelength range from 80 to 600 nm. Total pressures were varied from 1 to approximately 1.7 atm. Similarly absorption measurements were carried out in the visible region from 420 to 580 nm over a temperature range from about 1000 to 1800 K. Total pressure for these measurements was 1.0 atm. The emission results exhibited relatively no emission at wavelengths below 250 nm over the range of temperatures investigated. At temperatures in excess of 1800 K an additional emission band centered at 310 nm appears and becomes more well defined at higher temperatures. Essentially no pressure effect was observed with respect to emission at pressures up to 1.7 atm.

  17. Recent measurements concerning uranium hexafluoride-electron collision processes

    Science.gov (United States)

    Trajmar, S.; Chutjian, A.; Srivastava, S.; Williams, W.; Cartwright, D. C.

    1976-01-01

    Scattering of electrons by UF6 molecules was studied at impact energies ranging from 5 to 100 eV and momentum transfer, elastic and inelastic scattering cross sections were determined. The measurements also yielded spectroscopic information which made possible to extend the optical absorption cross sections from 2000 angstroms to 435 angstroms. It was found that UF6 is a very strong absorber in the vacuum UV region. No transitions were found to lie below the onset of the optically detected 3.0 eV feature.

  18. Indirect NMR detection of 235U in gaseous uranium hexafluoride

    OpenAIRE

    Ursu, I.; Demco, D.E.; Bogdan, M.; Fitori, P.; Darabont, A.

    1985-01-01

    The possibility to use nuclear magnetic resonance in indirect detection of the 235U nucleus in gaseous UF6 is discussed. The 19F absorption spectra linewidths in gaseous UF6 was investigated as a function of 235U enrichment, revealing a dependence on the isotope concentration. The 19F-235U indirect scalar coupling modulated by 235U quadrupole relaxation is the relaxation mechanism responsible for this enrichment effect.

  19. Condensation of uranium hexafluoride in supersonic Laval nozzle flow

    Science.gov (United States)

    Okada, Y.; Isomura, S.; Ashimine, K.; Takeuchi, K.

    1998-08-01

    Condensation, by homogeneous nucleation, of UF6 carried in a mixture of argon and methane was studied experimentally in a continuously operating supersonic Laval nozzle. The onset of condensation was detected by Rayleigh light scattering. Measurements of static pressure in the nozzle, together with the equations of isentropic flow, permitted the determination of the relation between the pressure of UF6, Pk, and the temperature, Tc, at the observed onset of condensation. The experiments addressed conditions of condensation onset in the range 80

  20. Negative ion-uranium hexafluoride charge transfer reactions

    Science.gov (United States)

    Streit, Gerald E.; Newton, T. W.

    1980-10-01

    The flowing afterglow technique has been used to study the process of charge transfer from selected negative ions (F-, Cl-, Br-, I-, SF6-) to UF6. The sole ionic product in all cases was observed to be UF6-. Data analysis was complicated by an unexpected coupling of chemical and diffusive ion loss processes when UF6- product ions were present. The rate coefficients for the charge transfer processes are (k in 10-9 cm3 molecule-1 s-1) F-, 1.3; Cl-, 1.1; Br-, 0.93; I-, 0.77; and SF6-, 0.69. The rate constants agree quite well with the classical Langevin predictions.

  1. Some economic aspects of the low enriched uranium production

    International Nuclear Information System (INIS)

    At the Technical Committee Meeting on Economics of Low Enriched Uranium 14 papers were presented. A separate abstract was prepared for each of these papers. The five technical sessions covered several economic aspects of uranium concentrates production, conversion into uranium hexafluoride and uranium enrichment and the recycling of U and Pu in LWR. Four Panel discussions were held to discuss the uranium market trends, the situation of conversion industry, the reprocessing and the uranium market, the future trends of enrichment and the economics of LWRs compared with other reactors. Refs, figs and tabs

  2. Uranium - the element: its occurrence and uses

    International Nuclear Information System (INIS)

    Uranium metal and its compounds have been of great interest to physicists and chemists due to its use for both civil and military applications, e.g. production of electricity, use in the medical field and for making nuclear weapons. This review paper describes the occurrence, chemistry and metallurgy of the element 'uranium', its conversion to stable compounds such as yellow cake, uranium tetrafluoride and uranium hexafluoride and the enrichment technologies and uses for both civil and military purposes. The paper is meant for ready reference for students and teachers in connection with the recent spate of interest shown in nuclear power generation in Pakistan and abroad. (author)

  3. The triple point of sulfur hexafluoride

    Science.gov (United States)

    Rourke, P. M. C.

    2016-04-01

    A cryogenic fixed point cell has been filled with high purity (99.999%) sulfur hexafluoride (SF6) and measured in an adiabatic closed-cycle cryostat system. Temperature measurements of the SF6 melting curve were performed using a capsule-type standard platinum resistance thermometer (CSPRT) calibrated over the International Temperature Scale of 1990 (ITS-90) subrange from the triple point of equilibrium hydrogen to the triple point of water. The measured temperatures were corrected by 0.37 mK for the effects of thermometer self-heating, and the liquidus-point temperature estimated by extrapolation to melted fraction F  =  1 of a simple linear regression versus melted fraction F in the range F  =  0.53 to 0.84. Based on this measurement, the temperature of the triple point of sulfur hexafluoride is shown to be 223.555 23(49) K (k  =  1) on the ITS-90. This value is in excellent agreement with the best prior measurements reported in the literature, but with considerably smaller uncertainty. An analysis of the detailed uncertainty budget of this measurement suggests that if the triple point of sulfur hexafluoride were to be included as a defining fixed point of the next revision of the International Temperature Scale, it could do so with a total realization uncertainty of approximately 0.43 mK, slightly larger than the realization uncertainties of the defining fixed points of the ITS-90. Since the combined standard uncertainty of this SF6 triple point temperature determination is dominated by chemical impurity effects, further research exploring gas purification techniques and the influence of specific impurity species on the SF6 triple point temperature may bring the realization uncertainty of SF6 as a fixed point material into the range of the defining fixed points of the ITS-90.

  4. Removal of hydrogen fluoride from uranium plant emissions

    International Nuclear Information System (INIS)

    Uranium production technology involves the use of hydrogen fluoride at various stages. It is used in the production of uranium tetrafluoride as well as for the production of fluorine for the conversion of tetrafluoride to hexafluoride in isotopic enrichment plants. The sources of HF pollution in the industry, besides accidental spillages and leakages, are the final off-gases from the UF4 production process or from the hydrogen reduction of hexafluoride (where such process is adopted), venting of tanks and reactors containing HF, safety pressure rupture discs as well as dust collection and ventilation systems

  5. 78 FR 52905 - Low Enriched Uranium From France: Initiation of Expedited Changed Circumstances Review, and...

    Science.gov (United States)

    2013-08-27

    ... Antidumping Duty Order: Low Enriched Uranium From France, 67 FR 6680 (February 13, 2002). foreign utility end...: Final Results of Antidumping Duty Changed Circumstances Review, 77 FR 19642 (April 2, 2012) (Final... uranium hexafluoride (UF 6 ) with a U\\235\\ product assay of less than 20 percent that has not...

  6. 78 FR 63518 - Uranium Enrichment Fuel Cycle Inspection Reports Regarding Louisiana Energy Services, National...

    Science.gov (United States)

    2013-10-24

    ..., New Mexico, and has authorized the introduction of uranium hexafluoride (UF 6 ) into cascades numbered... COMMISSION Uranium Enrichment Fuel Cycle Inspection Reports Regarding Louisiana Energy Services, National... 4th day of October, 2013. For the U.S. Nuclear Regulatory Commission. Brian W. Smith, Chief,...

  7. Uranium refining and conversion plant decommissioning project

    International Nuclear Information System (INIS)

    The uranium refining and conversion plant (URCP) at Ningyo-toge was constructed in 1981 for the purpose of demonstrating on refining and conversion process from yellow cake (or uranium trioxide) to uranium hexafluoride by way of uranium tetrafluoride. For 20 years, 385 tons of natural uranium hexafluoride and 336 tons of reprocessed uranium hexafluoride (approximately) was produced. There are two different type of refining processes in the URCP. One is the wet process by converting the natural uranium and the other is the dry conversion process for the reprocessed uranium. The dismantling of the dry process facilities began in March, 2008. It was found the large amount of uranium residuals such as wet slurry and powder uranium inside the vessels and pipes. Therefore, we have to take care of the spread of the contamination during dismantling works. The basic strategy concerning plant dismantling were the optimization of the total labor costs and the minimization of the radioactive wastes generated. The dismantling procedure is shown below; 1) measuring doserate by using high sensitivity surveymeters, and nuclide identification by using gamma ray spectrometry, 2) estimating uranium mass inventory, 3) planning work force distributions with radiological survey staffs, 4) deciding dismantling methods concretely, 5) decontaminating schematically if required, 6) collecting detailed data of working conditions, 7) measuring and classifying contaminated materials, 8) managements of radioactive waste drum and non-contaminated equipment, 9) control for personal exposures. Almost all equipment will be decontaminated except building decontamination it by around 2013FY. In addition, the secondary wastes were also yielded. Few thousands man-days were necessary for this project. The measurement data have not showed the high environmental radiation doserate, generally less than 0.3μSv/h. However, by the trace of the reprocessed uranium, the trans-uranium nuclides such as uranium

  8. Porous Organic Cages for Sulfur Hexafluoride Separation.

    Science.gov (United States)

    Hasell, Tom; Miklitz, Marcin; Stephenson, Andrew; Little, Marc A; Chong, Samantha Y; Clowes, Rob; Chen, Linjiang; Holden, Daniel; Tribello, Gareth A; Jelfs, Kim E; Cooper, Andrew I

    2016-02-10

    A series of porous organic cages is examined for the selective adsorption of sulfur hexafluoride (SF6) over nitrogen. Despite lacking any metal sites, a porous cage, CC3, shows the highest SF6/N2 selectivity reported for any material at ambient temperature and pressure, which translates to real separations in a gas breakthrough column. The SF6 uptake of these materials is considerably higher than would be expected from the static pore structures. The location of SF6 within these materials is elucidated by X-ray crystallography, and it is shown that cooperative diffusion and structural rearrangements in these molecular crystals can rationalize their superior SF6/N2 selectivity. PMID:26757885

  9. Helium and Sulfur Hexafluoride in Musical Instruments

    Science.gov (United States)

    Forinash, Kyle; Dixon, Cory L.

    2014-11-01

    The effects of inhaled helium on the human voice were investigated in a recent article in The Physics Teacher.1 As mentioned in that article, demonstrations of the effect are a popular classroom activity. If the number of YouTube videos is any indication, the effects of sulfur hexafluoride on the human voice are equally popular. However, there appears to be little information available on the effects of either of these gases on musical instruments.2 We describe here the results of a student project that involved measuring the frequency shifts in an organ pipe, a trumpet, and a trombone as the result of filling the instruments with these two gases. The project was one of several possible end-of-semester projects required in an elective science of sound course for non-science majors.

  10. Positron production in crossed beams of bare uranium nuclei

    OpenAIRE

    U. Müller; Reus, T.; Reinhardt, J.; Müller, B.; Greiner, Walter

    2006-01-01

    Positron creation in crossed-beam collisions of high-energy, fully stripped heavy ions is investigated within the coupled-channel formalism. In comparison with fixed-target collisions of highly stripped heavy-ion projectiles positron production probabilities are enhanced by more than one order of magnitude. The increase results from the possibility to excite electrons from the negative energy continuum into all bound states. The positron spectrum is shifted towards higher energies because of ...

  11. Chemical treatment of ammonium fluoride solution in uranium reconversion plant

    International Nuclear Information System (INIS)

    A chemical procedure is described for the treatment of the filtrate, produced from the transformation of uranium hexafluoride (U F6) into ammonium uranyl carbonate (AUC). This filtrate is an intermediate product in the U F6 to uranium dioxide (U O2) reconversion process. The described procedure recovers uranium as ammonium peroxide fluoro uranate (APOFU) by precipitation with hydrogen peroxide (H2 O2), and as later step, its calcium fluoride (CaF2) co-precipitation. The recovered uranium is recycled to the AUC production plant. (author)

  12. Recovery of uranium values from ammonium diuranate filtrate

    International Nuclear Information System (INIS)

    In the conversion of uranium hexafluoride (UF6) to UO2 or U metal powder, ammonium diuranate filtrate (ADUF) is generated by precipitation of uranyl fluoride solution (UO2F2) with ammonium hydroxide solution (NH4OH). This filtrate contains uranium in the range of 150-200 mg/l and fluoride ions in the range of 10-15 g/l. Uranium is present in the filtrate in hexavalent state as mixed fluoride complex particularly, UO2F2.3NH4F, which is quite soluble in aqueous medium and leads to loss of precious uranium in the effluent stream and also poses disposal issues

  13. 78 FR 21100 - Low Enriched Uranium From France: Final Results of the Expedited Second Sunset Review of the...

    Science.gov (United States)

    2013-04-09

    ... FR 6680 (February 13, 2002). On December 1, 2012, the Department initiated the second sunset review... Initiation of Five-Year (``Sunset'') Review, 77 FR 71684 (December 3, 2012). The Department received a notice... by the order is all low enriched uranium (``LEU''). LEU is enriched uranium hexafluoride (UF 6 )...

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

    Energy Technology Data Exchange (ETDEWEB)

    Guillet, H

    1959-02-01

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

  15. Reactions of technetium hexafluoride with nitric acid, nitrosyl fluoride, and nitryl fluoride

    Science.gov (United States)

    Holloway, J. H.; Selig, H.

    1970-01-01

    Stoichiometry of technetium hexafluoride reactions is studied. Magnetic properties and infrared spectra of reaction products are studied and compared with those of analogous complexes of the hexafluorides of tungsten, rhenium, and osmium.

  16. Advances in uranium refining and conversion

    International Nuclear Information System (INIS)

    One of the most important steps in the nuclear fuel cycle is the uranium refining and conversion which goes from the yellow cake to three different products: uranium dioxide, natural metallic uranium and uranium hexafluoride. The total volume of this industry, at the present time, is nearly of 40,000 t U per year and at the end of the present century it would have reached the 60,000 t U per year. The refining and conversion of reprocessed uranium that can be extracted by treating irradiated fuel become equally important for recycling recovered fuel. In response to the growing interest in these topics, the IAEA convened a Technical Committee Meeting with the attendance of 37 experts from 21 countries. This technical document contains the 20 papers presented during the meeting. A separate abstract was prepared for each of these papers

  17. Zeolites for the selective adsorption of sulfur hexafluoride.

    Science.gov (United States)

    Matito-Martos, I; Álvarez-Ossorio, J; Gutiérrez-Sevillano, J J; Doblaré, M; Martin-Calvo, A; Calero, S

    2015-07-21

    Molecular simulations have been used to investigate at the molecular level the suitability of zeolites with different topology on the adsorption, diffusion and separation of a nitrogen-sulfur hexafluoride mixture containing the latter at low concentration. This mixture represents the best alternative for the sulfur hexafluoride in industry since it reduces the use of this powerful greenhouse gas. A variety of zeolites are tested with the aim to identify the best structure for the recycling of sulfur hexafluoride in order to avoid its emission to the atmosphere and to overcome the experimental difficulties of its handling. Even though all zeolites show preferential adsorption of sulfur hexafluoride, we identified local structural features that reduce the affinity for sulfur hexafluoride in zeolites such as MOR and EON, providing exclusive adsorption sites for nitrogen. Structures such as ASV and FER were initially considered as good candidates based on their adsorption features. However, they were further discarded based on their diffusion properties. Regarding operation conditions for separation, the range of pressure that spans from 3 × 10(2) to 3 × 10(3) kPa was identified as the optimal to obtain the highest adsorption loading and the largest SF6/N2 selectivity. Based on these findings, zeolites BEC, ITR, IWW, and SFG were selected as the most promising materials for this particular separation. PMID:26099734

  18. The reduction of the plutonium hexafluoride by the gaseous reagents

    International Nuclear Information System (INIS)

    Some questions of the direct reduction of plutonium hexafluoride to dioxide in oxygen-methane plume at different ratios of initial components are investigated. Basic factors impacting on residual fluorine content in plutonium dioxide, and its filled density are determined. Plutonium dioxide samples with the fluorine content no more than 5 x 10 -3 % by mass are obtained. Mechanism of the reduction is suggested. Prospects in the application of carbon oxide as reductant for the preparation of actinide dioxides by the direct reduction of conforming hexafluorides are shown

  19. Gas chromatographic analysis of trace gas impurities in tungsten hexafluoride.

    Science.gov (United States)

    Laurens, J B; de Coning, J P; Swinley, J M

    2001-03-01

    Highly reactive fluorinated gaseous matrices require special equipment and techniques for the gas chromatographic analysis of trace impurities in these gases. The impurities that were analysed at the low-microg/l levels included oxygen, nitrogen, carbon dioxide, carbon monoxide, sulfur hexafluoride and hydrogen. This paper describes the use of a system utilising backflush column switching to protect the columns and detectors in the analysis of trace gas impurities in tungsten hexafluoride. Two separate channels were used for the analysis of H2, O2, N2, CO, CO2 and SF6 impurities with pulsed discharge helium ionisation detection. PMID:11269587

  20. Licensed uranium mills, uranium hexafluoride production plants, and fuel facilities: a historical review through 1977

    International Nuclear Information System (INIS)

    The data base has information that pertains to the health, safety, and environmental aspects of the licenses. Consideration was given to also include safeguards aspects, but this was not appropriate since the safeguards licensing program is fairly new and separate licenses for safeguards are not issued. Insofar as the health, safety, and environmental aspects of the licenses are concerned, the data base represents a comprehensive history of licensing actions and licensee performance compiled as one document

  1. Study on the enrichment of Sulfur Hexafluoride in the tmosphere through polyimide hollow fiber membrane

    Directory of Open Access Journals (Sweden)

    Wang Weixian

    2016-01-01

    Full Text Available Sulfur hexafluoride is per molecule the strongest greenhouse gas know, the features have brought SF6 into the climatic impact discussion aimed at reduction of emissions. The separation effects of sulfur hexafluoride in the atmosphere are studied through polyimide hollow fiber membrane with different conditions on pressure drop, gas flow and temperature. The sulfur hexafluoride concentration increased with increased pressure drop of the membrane, increased temperature and decreased non-filtrate flow flux; the recovery of sulfur hexafluoride exceeds 93%, enrichment coefficient was 18.5; sulfur hexafluoride is not detected at the flux of the filtrate flow, which means sulfur hexafluoride is riddled by membrane. The results showed that polyimide hollow fiber membrane can effectively separate sulfur hexafluoride from mixed gas

  2. Beneficial Uses of Depleted Uranium

    International Nuclear Information System (INIS)

    Naturally occurring uranium contains 0.71 wt% 235U. In order for the uranium to be useful in most fission reactors, it must be enriched the concentration of the fissile isotope 235U must be increased. Depleted uranium (DU) is a co-product of the processing of natural uranium to produce enriched uranium, and DU has a 235U concentration of less than 0.71 wt%. In the United States, essentially all of the DU inventory is in the chemical form of uranium hexafluoride (UF6) and is stored in large cylinders above ground. If this co-product material were to be declared surplus, converted to a stable oxide form, and disposed, the costs are estimated to be several billion dollars. Only small amounts of DU have at this time been beneficially reused. The U.S. Department of Energy (DOE) has begun the Beneficial Uses of DU Project to identify large-scale uses of DU and encourage its reuse for the primary purpose of potentially reducing the cost and expediting the disposition of the DU inventory. This paper discusses the inventory of DU and its rate of increase; DU disposition options; beneficial use options; a preliminary cost analysis; and major technical, institutional, and regulatory issues to be resolved

  3. Electron paramagnetic resonance and electron nuclear double resonance of 237-neptunium hexafluoride in uranium hexafluoride single crystals

    Science.gov (United States)

    Butler, James E.; Hutchison, Clyde A., Jr.

    1981-03-01

    The EPR and ENDOR spectra of 237NpF6 molecules dilutely substituted for host molecules in single crystals of UF6 at temperatures between 1.2 and 2.1 °K have been obtained at microwave frequencies, ˜9.4 and ˜9.7 GHz. Approximate values are given for the parameters in a spin Hamiltonian formalism that describes the measurements. The results are discussed.

  4. Very Late Bare Metal Stent Thrombosis

    Directory of Open Access Journals (Sweden)

    Mariana Soto Herrera

    2013-01-01

    Full Text Available Very late stent thrombosis is a rare and not-well-understood complication after bare metal stent implantation. It usually presents as an ST elevation acute coronary syndrome and it is associated with high rates of morbidity and mortality. Pathophysiologic mechanisms are not well defined; nevertheless, recent studies have proposed a neoatherosclerotic process as the triggering mechanism. We present the case of a patient with bare metal very late stent thrombosis 12 years after implantation.

  5. Very Late Bare Metal Stent Thrombosis

    Science.gov (United States)

    Soto Herrera, Mariana; Restrepo, José A.; Felipe Buitrago, Andrés; Gómez Mejía, Mabel; Díaz, Jesús H.

    2013-01-01

    Very late stent thrombosis is a rare and not-well-understood complication after bare metal stent implantation. It usually presents as an ST elevation acute coronary syndrome and it is associated with high rates of morbidity and mortality. Pathophysiologic mechanisms are not well defined; nevertheless, recent studies have proposed a neoatherosclerotic process as the triggering mechanism. We present the case of a patient with bare metal very late stent thrombosis 12 years after implantation. PMID:24829831

  6. Bare Higgs mass at Planck scale

    CERN Document Server

    Hamada, Yuta; Oda, Kin-ya

    2013-01-01

    In a certain quantum gravity/string theory context, it is possible that not only the physical Higgs mass but also the bare one (and hence the radiative corrections as well) can vanish at the Planck/string scale. We compute one and two loop quadratic divergent contributions to the bare Higgs mass in terms of the bare couplings in the Standard Model (SM). We approximate the bare couplings at the ultraviolet cutoff scale by the MSbar ones at the same scale, which we evaluate for the Higgs mass around 126GeV in the SM. We obtain the cutoff scale dependence of the bare Higgs mass up to two loop orders, and examine where it becomes zero. We find that if we take the current central value for the top quark pole mass, 173GeV, the bare Higgs mass vanishes at about 10^{23}GeV. With a 1.3 sigma smaller mass, 170GeV, the scale can be of the order of the Planck scale.

  7. The rate of sulfur hexafluoride escape from a plastic syringe.

    Science.gov (United States)

    Humayun, M S; Yeo, J H; Koski, W S; Michels, R G

    1989-06-01

    Sulfur hexafluoride (SF6) gas is widely used for internal tamponade during retinal reattachment surgery and is commonly injected into the eye from a 10-mL plastic syringe. The rate of diffusion of SF6 out of a plastic syringe has not bee studied. We measured the percentage of SF6 gas in a 10-mL plastic syringe by gas chromatography, confirmed by infrared spectrometry. Measurements were obtained immediately after aspiration, and at 30 s and 10, 15, 60, 90, and 120 minutes, and 18 hours. A marked decrease in SF6 concentration, from 97% at 30 s to 76% at 60 minutes and 2% at 18 hours, was noted. The results were highly reproducible. Sulfur hexafluoride gas should be injected into the patient's eye as soon as possible after aspiration from the tank to ensure accurate concentrations. PMID:2730405

  8. Description of an engineering-scale facility for uranium fluorination studies

    International Nuclear Information System (INIS)

    In the research program of power reactor fuel reprocessing by fluoride volatility process, the engineering facility was constructed to establish the techniques of handling kilogram quantities of fluorine and uranium hexafluoride and to obtain engineering data on the uranium fluidized-bed oxidation and fluorination. This facility is designed for a capacity of 5 kg per batch. Descriptions on the facility and equipment are given, including design philosophy, safety and its analysis. (auth.)

  9. Study on the enrichment of Sulfur Hexafluoride in the tmosphere through polyimide hollow fiber membrane

    OpenAIRE

    Wang Weixian; Wang Yaoqin; Li Weiping; Yuan Yuan

    2016-01-01

    Sulfur hexafluoride is per molecule the strongest greenhouse gas know, the features have brought SF6 into the climatic impact discussion aimed at reduction of emissions. The separation effects of sulfur hexafluoride in the atmosphere are studied through polyimide hollow fiber membrane with different conditions on pressure drop, gas flow and temperature. The sulfur hexafluoride concentration increased with increased pressure drop of the membrane, increased temperature and decreased non-filtrat...

  10. Low-energy electron collisions with sulfur hexafluoride, SF6

    OpenAIRE

    Winstead, C.; McKoy, V.

    2004-01-01

    We report calculated cross sections for elastic and electronically inelastic collisions of low-energy electrons with sulfur hexafluoride, SF6. Elastic cross sections are computed within the fixed-nuclei approximation, with polarization effects incorporated. Inelastic cross sections for nine low-lying states are computed in a few-channel approximation. We compare our cross sections to previous experimental and computational results where possible.

  11. Bare nominals and reference to capacities

    NARCIS (Netherlands)

    Swart, Henriëtte de; Winter, Y.; Zwarts, J.

    2007-01-01

    Prefinal version. This paper concentrates on the syntax and semantics of bare nominals in Germanic and Romance languages. These languages do not normally allow nominals to occur without an article. However, some syntactic configurations, including predicative constructions, supplementives and some p

  12. Department of Energy depleted uranium recycle

    International Nuclear Information System (INIS)

    With its strategic supply of depleted uranium, the Department of Energy is studying reuse of the material in nuclear radiation shields, military hardware, and commercial applications. the study is expected to warrant a more detailed uranium recycle plan which would include consideration of a demonstration program and a program implementation decision. Such a program, if implemented, would become the largest nuclear material recycle program in the history of the Department of Energy. The bulk of the current inventory of depleted uranium is stored in 14-ton cylinders in the form of solid uranium hexafluoride (UF6). The radioactive 235U content has been reduced to a concentration of 0.2% to 0.4%. Present estimates indicate there are about 55,000 UF6-filled cylinders in inventory and planned operations will provide another 2,500 cylinders of depleted uranium each year. The United States government, under the auspices of the Department of Energy, considers the depleted uranium a highly-refined strategic resource of significant value. A possible utilization of a large portion of the depleted uranium inventory is as radiation shielding for spent reactor fuels and high-level radioactive waste. To this end, the Department of Energy study to-date has included a preliminary technical review to ascertain DOE chemical forms useful for commercial products. The presentation summarized the information including preliminary cost estimates. The status of commercial uranium processing is discussed. With a shrinking market, the number of chemical conversion and fabrication plants is reduced; however, the commercial capability does exist for chemical conversion of the UF6 to the metal form and for the fabrication of uranium radiation shields and other uranium products. Department of Energy facilities no longer possess a capability for depleted uranium chemical conversion

  13. Transformations of highly enriched uranium into metal or oxide

    International Nuclear Information System (INIS)

    The enriched uranium workshops in Cadarache have a double purpose on the one hand to convert uranium hexafluoride into metal or oxide, and on the other hand to recover the uranium contained in scrap materials produced in the different metallurgical transformations. The principles that have been adopted for the design and safety of these workshops are reported. The nuclear safety is based on the geometrical limitations of the processing vessels. To establish the processes and the technology of these workshops, many studies have been made since 1960, some of which have led to original achievements. The uranium hexafluoride of high isotopic enrichment is converted either by injection of the gas into ammonia or by an original process of direct hydrogen reduction to uranium tetrafluoride. The uranium contained m uranium-zirconium metal scrap can be recovered by combustion with hydrogen chloride followed treatment of the uranium chloride by fluorine in order to obtain the uranium in the hexafluoride state. Recovery of the uranium contained m various scrap materials is obtained by a conventional refining process combustion of metallic scrap, nitric acid dissolution of the oxide, solvent purification by tributyl phosphate, ammonium diuranate precipitation, calcining, reduction and hydro fluorination into uranium tetrafluoride, bomb reduction by calcium and slag treatment. Two separate workshops operate along these lines one takes care of the uranium with an isotopic enrichment of up to 3 p. 100, the other handles the high enrichments. The handling of each step of this process, bearing in mind the necessity for nuclear safety, has raised some special technological problems and has led to the conception of new apparatus, in particular the roasting furnace for metal turnings, the nitric acid dissolution unit, the continuous precipitator and ever safe filter and dryer for ammonium diuranate, the reduction and hydro fluorination furnace and the slag recovery apparatus These are

  14. Emergency exposure levels for natural uranium

    International Nuclear Information System (INIS)

    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)

  15. Thermal Photons From Magnetized Bare Strange Stars

    CERN Document Server

    Méndez, Enrique Moreno; Patiño, Leonardo; Ortega, Patricia

    2013-01-01

    A plasma made out of strange-quark matter (SQM) and electrons, has a rather high plasma frequency (>20 MeV). Thus, a compact star made of such material all the way up to its surface, i.e., a bare strange star, would be unable to radiate away its thermal emission. We use the MIT-bag model and assume that SQM is the ground state of nuclear matter at high density. We investigate whether the presence of a magnetic field will allow propagation of radiation at frequencies below the SQM plasma frequencies. Hence, we study the presence of gyrofrequencies in a SQM plasma permeated by a strong magnetic field (B > 10^{12} G). We find that small regions in the frequency spectrum allow radiation propagation due to the presence of the magnetic fields. It is likely that narrow bands of radiation would likely be observable from magnetized bare strange stars .

  16. Bare metal stenting of the iliac arteries.

    Science.gov (United States)

    Kim, Tanner I; Schneider, Peter A

    2016-06-01

    A significant subset of patients with peripheral artery disease (PAD) has iliac artery involvement that requires treatment. The development of bare metal stents has improved the short- and long-term outcomes of endovascular repair and has become first line therapy. Open surgical bypass has been reserved for extremely complex anatomic morphologies or endovascular failures. It is unclear whether primary stenting is superior to angioplasty with provisional stenting but if angioplasty is used alone, it is likely only appropriate for the most focal lesions. Self-expanding and balloon-expandable stents have unique characteristics that are suitable to different lesion morphologies. Both stent-types have demonstrated similar outcomes. Herein, we review the practice and results of bare metal stents in the iliac arteries. PMID:27035892

  17. Separation and recovery of molybdenum values from uranium process waste

    International Nuclear Information System (INIS)

    A method is described of recovering molybdenum and uranium values from a process waste generated from the production of nuclear-grade uranium hexafluoride which consists of: (a) hydrolysing the process waste which contains UF6, MoF6 and MoOF4 in an aqueous solution containing ammonium carbonate and ammonium hydroxide thereby forming ammonium uranyl carbonate; (b) digesting while maintaining a pH > 9, the resulting mother liquor at a temperature of about 600-800C. to evolve CO2 and convert the ammonium uranyl carbonate to solid ammonium diuranate; (c) filtering, washing and drying the solid ammonium diuranate

  18. Water Accommodation on Bare and Coated Ice

    Science.gov (United States)

    Kong, Xiangrui

    2015-04-01

    A good understanding of water accommodation on ice surfaces is essential for quantitatively predicting the evolution of clouds, and therefore influences the effectiveness of climate models. However, the accommodation coefficient is poorly constrained within the literature where reported values vary by up to three orders of magnitude. In addition, the complexity of the chemical composition of the atmosphere plays an important role in ice phase behavior and dynamics. We employ an environmental molecular beam (EMB) technique to investigate molecular water interactions with bare and impurity coated ice at temperatures from 170 K to 200 K. In this work, we summarize results of water accommodation experiments on bare ice (Kong et al., 2014) and on ice coated by methanol (Thomson et al., 2013), butanol (Thomson et al., 2013) and acetic acid (Papagiannakopoulos et al., 2014), and compare those results with analogous experiments using hexanol and nitric acid coatings. Hexanol is chosen as a complementary chain alcohol to methanol and butanol, while nitric acid is a common inorganic compound in the atmosphere. The results show a strong negative temperature dependence of water accommodation on bare ice, which can be quantitatively described by a precursor model. Acidic adlayers tend to enhance water uptake indicating that the system kinetics are thoroughly changed compared to bare ice. Adsorbed alcohols influence the temperature dependence of the accommodation coefficient and water molecules generally spend less time on the surfaces before desorbing, although the measured accommodation coefficients remain high and comparable to bare ice for the investigated systems. We conclude that impurities can either enhance or restrict water uptake in ways that are influenced by several factors including temperature and type of adsorbant, with potential implications for the description of ice particle growth in the atmosphere. This work was supported by the Swedish Research Council and

  19. Measurement of the diffusion coefficient of sulfur hexafluoride in water

    OpenAIRE

    King, D. B.; Saltzman, E. S.

    1995-01-01

    Sulfur hexafluoride has been widely used in field studies and laboratory experiments to develop a relationship between gas transfer and wind speed. The interpretation of the data from such studies requires the diffusion coefficient of SF6 (D SF6), which has not previously been measured. In this study, D SF6 has been determined in pure water and in 35‰ NaCl over a temperature range of 5–25°C. The measurements were made using a continuous-flow diffusion cell where SF6 fl...

  20. Photoreductive degradation of sulfur hexafluoride in the presence of styrene

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Sulfur hexafluoride (SF6) is known as one of the most powerful greenhouse gases in the atmosphere. Reductive photodegradation of SM6 by styrene has been studied with the purpose of developing a novel remediation for sulfur hexafluoride pollution. Effects of reaction conditions on the destruction and removal efficiency (DRE) of SF6 are examined in this study. Both initial styrene-to-SF6 ratio and initial oxygen concentration exert a significant influence on DRE. SF6 removal efficiency reaches a maximum value at the initial styrene-to-SF6 ratio of 0.2. It is found that DRE increases with oxygen concentration over the range of 0 to 0.09 mol/m3 and then decreases with increasing oxygen concentration. When water vapor is fed into the gas mixture, DRE is slightly enhanced over the whole studied time scale. The X-ray Photoelectron Spectroscopy (XPS) analysis, together with gas chromatography-mass spectrometry (GC-MS) and Fourier Transform Infrared spectroscopy (FT-IR) analysis, prove that nearly all the initial fluorine residing in the gas phase is in the form of SiF4, whereas, the initial sulfur is deposited in the form of elemental sulfur, after photodegradation. Free from toxic byproducts, photodegradation in the presence of styrene may serve as a promising technique for SF6 abatement.

  1. Photoreductive degradation of sulfur hexafluoride in the presence of styrene.

    Science.gov (United States)

    Huang, Li; Gu, Dinghong; Yang, Longyu; Xia, Lanyan; Zhang, Renxi; Hou, Huiqi

    2008-01-01

    Sulfur hexafluoride (SF6) is known as one of the most powerful greenhouse gases in the atmosphere. Reductive photodegradation of SF6 by styrene has been studied with the purpose of developing a novel remediation for sulfur hexafluoride pollution. Effects of reaction conditions on the destruction and removal efficiency (DRE) of SF6 are examined in this study. Both initial styrene-to-SF6 ratio and initial oxygen concentration exert a significant influence on DRE. SF6 removal efficiency reaches a maximum value at the initial styrene-to-SF6 ratio of 0.2. It is found that DRE increases with oxygen concentration over the range of 0 to 0.09 mol/m3 and then decreases with increasing oxygen concentration. When water vapor is fed into the gas mixture, DRE is slightly enhanced over the whole studied time scale. The X-ray Photoelectron Spectroscopy (XPS) analysis, together with gas chromatography-mass spectrometry (GC-MS) and Fourier Transform Infrared spectroscopy (FT-IR) analysis, prove that nearly all the initial fluorine residing in the gas phase is in the form of SiF4, whereas, the initial sulfur is deposited in the form of elemental sulfur, after photodegradation. Free from toxic byproducts, photodegradation in the presence of styrene may serve as a promising technique for SF6 abatement. PMID:18574959

  2. Alternative route for UF6 conversion towards UF4 to produce metallic uranium

    International Nuclear Information System (INIS)

    The present work is focused on a study for the preparation of uranium tetrafluoride UF4 appropriate for the metallic uranium (U0) reduction from solutions obtained by uranium hexafluoride (UF6) hydrolysis using stannous chloride (Sn Cl2) as the reducing agent. The objective of the present study has been on one hand to gather experience within the uranium tetrafluoride preparation technology field by making use of an alternative, safe and simple process with which the knowledge obtained through uranium hexafluoride hydrolysis solution could be used, and on the other hand to determine the best conditions for obtaining this product, in view of the effect of experimental variables over the physical and chemical characteristics of the powder obtained, particularly the content of the uranium dioxide (UO2), uranyl fluoride (UO2F2), the contents of hydrating water and specific surface, in order to make a correlation of those properties with the yielding of the reduction reaction caused by compounds at uranium metal producing. The metallurgical process for metallic uranium production is updated. (author)

  3. Ikke bare porno på mobilen

    DEFF Research Database (Denmark)

    Andersen, Tem Frank

    2013-01-01

    Den britiske børne- og ungdomsforsker professor Sonia Livingstone ved London School of Economics viser gennem en række interviews, at billeder af eksplicitte sexhandlinger er en velkendt del af den ungdommelige cirkulation af ’hverdagspornografisk’ materiale (Ringrose et al. 2012). ’Sexting’ er a...... altså ikke bare porno på en mobilplatform. Det er handlinger og værgestrategier, som unge piger er nødt til at forholde sig til i hverdagen, mens drengene umiddelbart ser ud til at slippe relativt let udenom den chikane, der kan ligge i ’sexting’....

  4. Magnetospheric activity of bare strange quark stars

    Science.gov (United States)

    Yu, J. W.; Xu, R. X.

    2011-06-01

    In the model of Ruderman and Sutherland, the binding energy problem is a severe problem when modelling normal neutron stars as pulsars, i.e. both ions (e.g. 5626Fe) and electrons on the normal neutron star surface can be pulled out freely by the unipolar generator induced electric field, so that sparking on the polar cap can hardly occur. This problem can be solved within the partially screened gap (PSG) model for neutron stars. However, in this paper, we study this problem extensively in a model of bare strange quark stars (BSSs). We find that the huge potential barrier built by the electric field in the vacuum gap above the polar cap can usually prevent electrons from streaming into the magnetosphere, unless the electric potential of a pulsar is sufficiently lower than that at the infinite interstellar medium. Other processes, such as the diffusion and thermionic emission of electrons, have also been included here. Our conclusions are as follows. Both positive and negative particles on the surface of a BSS are bound strongly enough to form a vacuum gap above its polar cap as long as the BSS is not charged (or not highly negative charged), and multi-accelerators can occur in the magnetosphere of the BSS. Our results may be helpful to distinguish normal neutron stars and bare quark stars using a pulsar's magnetospheric activities.

  5. Recovery of valuable products from the raffinate of uranium and thorium pilot-plant

    International Nuclear Information System (INIS)

    IPEN-CNEN/SP has being very active in refining yellow cake to pure ammonium diuranate which is converted to uranium trioxide, uranium dioxide, uranium tetra-and hexa-fluoride in sequential way. The technology of the thorium purification and its conversion to nuclear grade products has been a practice since several years as well. For both elements the major waste to be worked is the raffinate from purification via TBP-varsol in pulsed columns. In this paper the actual processing technology is reviewed with special emphasis on the recovery of valuable products, mainly nitric acid, ammonium nitrate, uranium, thorium and rare earth elements. Ammonium nitrate from the precipitation of uranium diuranate is of good quality, being radioactivity and uranium-free, and recommended to be applied as fertilizer. In conclusion the main effort is to maximize the recycle and reuse of the above mentioned chemicals. (author)

  6. Recovery of valuable products in liquid effluents from uranium and thorium pilot units

    International Nuclear Information System (INIS)

    IPEN-CNEN/SP has being very active in refining yellowcake to pure ammonium diuranate which is converted to uranium trioxide, uranium dioxide, uranium tetra- and hexafluoride in a sequential way. The technology of the thorium purification and its conversion to nuclear grade products has been a practice since several years as well. For both elements the major waste to be worked is the refinate from the solvent extraction column where uranium and thorium are purified via TBP-varsol in pulsed columns. In this paper the actual processing technology is reviewed with special emphasis on the recovery of valuable products, mainly nitric acid and ammonium nitrate. Distilled nitric acid and the final sulfuric acid as residue are recycle. Ammonium nitrate from the precipitation of uranium diuranate is of good quality, being radioactivity and uranium-free, and recommended to be applied as fertilizer. In conclusion the main effort is to maximise the recycle and reuse of the abovementioned chemicals. (author)

  7. Suzaku observations of 'bare' active galactic nuclei

    CERN Document Server

    Walton, D J; Fabian, A C; Gallo, L C; Reis, R C

    2012-01-01

    We present a X-ray spectral analysis of a large sample of 25 'bare' active galactic nuclei, sources with little or no complicating intrinsic absorption, observed with Suzaku. Our work focuses on studying the potential contribution from relativistic disc reflection, and examining the implications of this interpretation for the intrinsic spectral complexities frequently displayed by AGN in the X-ray bandpass. During the analysis, we take the unique approach of attempting to simultaneously undertake a systematic analysis of the whole sample, as well as a detailed treatment of each individual source, and find that disc reflection has the required flexibility to successfully reproduce the broadband spectrum observed for all of the sources considered. Where possible, we use the reflected emission to place constraints on the black hole spin for this sample of sources. Our analysis suggests a general preference for rapidly rotating black holes, which if taken at face value is most consistent with the scenario in whic...

  8. Development of uranium milling and conversion at Ningyo-toge Works

    International Nuclear Information System (INIS)

    In the Ningyo-toge Works of Power Reactor and Nuclear Fuel Development Corporation (PNC), technology development has proceeded on the series processes of uranium milling and conversion from uranium ore to uranium hexafluoride. The PNC process comprises the amine extraction of ore leach solution, the subsequent contact of the uranium-containing organic solvet with hydrochloric acid to convert uranyl sulfate complex anions to urayl chloride complex anions, and back extraction with water. The Uranium tetrafluoride anhydride produced by the wet method called PNC process is excellent in the handling and reaction for uranium hexafluoride conversion. From the results so far, a demonstration type plant is now being constructed. The following matters are described: review of uranium refining and the features of PNC process, heap leaching/ion exchange/solvent extraction, electrolytic reduction, the UF4.nH2O powder production by fluoride precipitation; UF*4sub(.n h)2O dehydration, and UF*4sub(/ u f)6** conversion. (J.P.N.)

  9. NUSIMEP-7: uranium isotope amount ratios in uranium particles

    International Nuclear Information System (INIS)

    The Institute for Reference Materials and Measurements (IRMM) has extensive experience in the development of isotopic reference materials and the organization of interlaboratory comparisons (ILC) for nuclear measurements in compliance with the respective international guidelines (ISO Guide 34:2009 and ISO/IEC 17043:2010). The IRMM Nuclear Signatures Interlaboratory Measurement Evaluation Program (NUSIMEP) is an external quality control program with the objective of providing materials for measurements of trace amounts of nuclear materials in environmental matrices. Measurements of the isotopic ratios of the elements uranium and plutonium in small amounts, typical of those found in environmental samples, are required for nuclear safeguards and security, for the control of environmental contamination and for the detection of nuclear proliferation. The measurement results of participants in NUSIMEP are evaluated according to international guidelines in comparison to independent external certified reference values with demonstrated metrological traceability and uncertainty. NUSIMEP-7 focused on measurements of uranium isotope amount ratios in uranium particles aiming to support European Safeguards Directorate General for Energy (DG ENER), the International Atomic Energy Agency's (IAEA) network of analytical laboratories for environmental sampling (NWAL) and laboratories in the field of particle analysis. Each participant was provided two certified test samples: one with single and one with double isotopic enrichment. These NUSIMEP test samples were prepared by controlled hydrolysis of certified uranium hexafluoride in a specially designed aerosol deposition chamber at IRMM. Laboratories participating in NUSIMEP-7 received the test samples of uranium particles on two graphite disks with undisclosed isotopic ratio values n(234U)/n(238U), n(235U)/n(238U) and n(236U)/n(238U). The uranium isotope ratios had to be measured using their routine analytical procedures

  10. Corrosion of metallic materials by uranium hexafluoride at high temperatures (1963)

    International Nuclear Information System (INIS)

    The corrosion of the following metals or alloys by UF6: nickel, monel, Inconel, gold, platinum, stainless steel, is studied in the temperature range from 300 to 1000 deg. C. The test method, designed to avoid heating the apparatus containing the corrosive fluid to a high temperature, consists in using threadlike samples heated by the Joule effect, the rest of the apparatus being maintained close to room temperature. This technique makes it possible also to determine continuously the penetration of the corrosion by measuring the electrical resistance of the sample with a double Thomson bridge. A series of rapid comparison tests shows that stainless steel, precious metals and Inconel are attacked far too rapidly to be used above 500 deg. C; only monel and especially nickel appear capable of resisting at high temperatures. The detailed examination of the behaviour of nickel shows that the metallic fluoride is volatilized and that this influences the corrosion rate. It shows also the existence of a temperature zone situated between 550 and 700 deg. C in which occurs A strong intergranular corrosion the cause of which appears to be the presence of impurities in the metal. (author)

  11. Uranium hexafluoride: A manual of good practice ORO 651 revision 6

    Energy Technology Data Exchange (ETDEWEB)

    Dyer, R.H. [Department of Energy, Oak Ridge, TN (United States)

    1991-12-31

    The United States Department of Energy publishes a document containing UF{sub 6} handling procedures and descriptions of the approved UF{sub 6} cylinders. Since its initial publication in 1966, it has been frequently revised to provide more and better information. The principle additions to the sixth revision which will be discussed are: (1) more detail on the physical and chemical properties of UF{sub 6}; (2) cold trap description and operation; (3) cylinder emptying and filling concepts; (4) basis for cylinder fill limits; (5) short- and long-term cylinder storage; and (6) cylinder photographs and drawings showing major dimensions.

  12. Nuclear criticality safety aspects of gaseous uranium hexafluoride (UF{sub 6}) in the diffusion cascade

    Energy Technology Data Exchange (ETDEWEB)

    Huffer, J.E. [Parallax, Inc., Atlanta, GA (United States)

    1997-04-01

    This paper determines the nuclear safety of gaseous UF{sub 6} in the current Gaseous Diffusion Cascade and auxiliary systems. The actual plant safety system settings for pressure trip points are used to determine the maximum amount of HF moderation in the process gas, as well as the corresponding atomic number densities. These inputs are used in KENO V.a criticality safety models which are sized to the actual plant equipment. The ENO V.a calculation results confirm nuclear safety of gaseous UF{sub 6} in plant operations..

  13. Nuclear criticality safety aspects of gaseous uranium hexafluoride (UF6) in the diffusion cascade

    International Nuclear Information System (INIS)

    This paper determines the nuclear safety of gaseous UF6 in the current Gaseous Diffusion Cascade and auxiliary systems. The actual plant safety system settings for pressure trip points are used to determine the maximum amount of HF moderation in the process gas, as well as the corresponding atomic number densities. These inputs are used in KENO V.a criticality safety models which are sized to the actual plant equipment. The ENO V.a calculation results confirm nuclear safety of gaseous UF6 in plant operations

  14. Process for removal of adhering or dust deposits in plants handling uranium hexafluoride

    International Nuclear Information System (INIS)

    In order to remove the deposits which arise from the hydrolysis products of UF6 and compounds containing oxygen, these are brought into contact with CBrF3 or CBr2F2 as compounds supplying bromine and with IF7 or the element fluorine as means of fluorisation, at least at room temperature. The range up to 130 millibar is suitable for the overall pressure for the reaction. (DG)

  15. Process for removal of adhering or dust deposits in plants handling uranium hexafluoride

    International Nuclear Information System (INIS)

    Deposits containing oxygen, of the type UO2F2 or its hydrate are removed in a UF6 plant by this process. The deposits are first treated with gaseous BBr3 or PBr and then with fluorine, iodine heptafluoride or other halogen fluorides. (DG)

  16. Process for removing firmly attached or dust deposits in plants for handling uranium hexafluoride

    International Nuclear Information System (INIS)

    The deposits of hydrolysis or reduction products of UF6 in the plants for enriching U235 are removed with BrF3. The BrF3 is present in liquid form and covers the plant walls with a film. The deposits of UO2F3 may be converted into UF6 and may thus be released. The reaction mixture is preferably used at a total pressure of up to 130 millibar. (DG)

  17. Safety analysis report on the ''Paducah Tiger'' protective overpack for 10-ton cylinders of uranium hexafluoride

    International Nuclear Information System (INIS)

    The ''Paducah Tiger'' is a protective overpack used in shipment of 10-ton cylinders of enriched UF6. The calculations and tests are described which made and which indicate that the overpack is in compliance with the type B packaging requirements of ERDA Manual Chapter 0529 and Title 10 Code Federal Regulations Part 71. (U.S.)

  18. Preliminary Hazard Analysis applied to Uranium Hexafluoride - UF6 production plant

    International Nuclear Information System (INIS)

    The purpose of this paper is to present the results of the Preliminary hazard Analysis applied to the UF6 Production Process, which is part of the UF6 Conversion Plant. The Conversion Plant has designed to produce a high purified UF6 in accordance with the nuclear grade standards. This Preliminary Hazard Analysis is the first step in the Risk Management Studies, which are under current development. The analysis evaluated the impact originated from the production process in the plant operators, members of public, equipment, systems and installations as well as the environment. (author)

  19. Mass spectrometer introduction line: application to the analysis of impurities in uranium hexafluoride

    International Nuclear Information System (INIS)

    The continuous mass-spectrometric analysis of impurities in UF6 is possible industrially if certain conditions imposed by the nature of the gas are respected. The gas introduction line arriving at the spectrometer's source makes it possible to fix the flow-rate, to control the inlet pressure and to selectively destroy the gas containing the impurities. The operational conditions for the line are defined and a description is given of the theoretical and experimental study of the various elements of which it is composed, i.e. the leak valve, the flow-meter, the chemical trap and the servo-mechanism making it possible to regulate and control the gas flow. The dynamic characteristics of the line's various components and the performance of the equipment in the case of the analyses considered are given. (author)

  20. The reduction of uranium hexafluoride by carbon tetrachloride in the gaseous phase

    International Nuclear Information System (INIS)

    The reduction of UF6 to UF4 by CCl4 in a 0.08 m diameter vertical glass reactor has been studied. In the tests, UF6 and CCl4, preheated to about 350 deg C, were fed into the reactor and the tower walls were held at about 500 deg C, the reaction was taking place almost completely in the gaseous phase. A high temperature flames can be visually observed by increasing in the reactant feed rates, and the brightness of the flame changes with the reactant feed rates. The conversion of UF6 is essentially complete if a CCl4 excess is maintained. The method is considered to be an effective process to meet continuous conversion of slightly enriched UF6

  1. Manual on safe production, transport, handling and storage of uranium hexafluoride

    International Nuclear Information System (INIS)

    This document includes a description of the physical, chemical and radiological properties of UF6 and related products, including information concerning their production, handling, storage and transportation and the management of the wastes which result. All the operations of UF6 management are considered form a safety point of view. The IAEA organized a series of meetings to consider the hazards of UF6 transport since considerable quantities of depleted, natural and enriched UF6 are transported between nuclear fuel sites. Storage of depleted UF6 is another important issue. Factors affecting long term storage are presented, especially site choice and cylinder corrosion. Other topics such as waste management, quality assurance and emergency preparedness which contribute to the overall safety of UF6 handling, are included. The intention of this document is to provide analysis of the safety implications of all stages of UF6 operations and to draw attention to specific features and properties of importance. 38 refs, figs, tabs

  2. Evaluation of selected detector systems for products formed in the atmospheric hydrolysis of uranium hexafluoride

    International Nuclear Information System (INIS)

    Sensitive detection of UF6 hydrolysis products, either by discontinuous sampling or by continuous or near real-time monitoring, is an important safety consideration for DOE contractors handling large quantities of UF6. Automated continuous or rapid intermittent remote sensing of these reaction products can provide an alarm signal when a preselected threshold value has been exceeded (absolute response) or when a significant emission excursion has occurred (rate of change of response). This report evaluates the performance of selected devices for the detection of airborne materials formed in the release of liquid UF6 (≅1.3 g) into an enclosed volume of 6 m3; these experiments were initiated on October 23, 1986. The detection principles investigated are: photometric, gas detector tubes, and electrochemical sensor

  3. a Measurement of the Homogeneous Rate of Thermal Dissociation of Uranium Hexafluoride by Shock Tube Densitometry

    Science.gov (United States)

    Scoles, Stephen Wesley

    1990-01-01

    A determination of the rate of homogeneous thermal dissociation of UF_6 is reported. The high temperature region of a shock tube generated flow was used to dissociate UF_6. Laser -schlieren diagnostic techniques were used to measure post -shock density gradient and shock wave velocity, from which the dissociation rate constant and post-shock conditions were determined. The unimolecular dissociation theory of Rice, Ramsparger, and Kassel was used to model the temperature - and density-dependent rate constants. When extrapolated to the high density limit the dissociation rate constant obtained is:rm k_infty = 3.51times 10^{13}{bf e}^{{-64.6+/-6.3 {kcal over mole}over R_{U}T }}{1over sec}.This result agrees with a reliable theoretical calculation by another investigator, but differs by two orders of magnitude from the only other experimental measurements in the open literature.

  4. The spectral properties of uranium hexafluoride and its thermal decomposition products

    Science.gov (United States)

    Krascella, N. L.

    1976-01-01

    This investigation was initiated to provide basic spectral data for gases of interest to the plasma core reactor concept. The attenuation of vacuum ultraviolet (VUV) radiation by helium at pressures up to 20 atm over path lengths of about 61 cm and in the approximate wavelength range between 80 and 300 nm was studied. Measurements were also conducted to provide basic VUV data with respect to UF6 and UF6/argon mixtures in the wavelength range between 80 and 120 nm. Finally, an investigation was initiated to provide basic spectral emission and absorption data for UF6 and possible thermal decomposition products of UF6 at elevated temperatures.

  5. Pair emission from bare magnetized strange stars

    CERN Document Server

    Melrose, D B; Peres-Menezes, D

    2006-01-01

    The dominant emission from bare strange stars is thought to be electron-positron pairs, produced through spontaneous pair creation (SPC) in a surface layer of electrons tied to the star by a superstrong electric field. The positrons escape freely, but the electrons are directed towards the star and quickly fill all available states, such that their degeneracy suppresses further SPC. An electron must be reflected and gain energy in order to escape, along with the positron. Each escaping electron leaves a hole that is immediately filled by another electron through SPC. We discuss the collisional processes that produce escaping electrons. When the Landau quantization of the motion perpendicular to the magnetic field is taken into account, electron-electron collisions can lead to an escaping electron only through a multi-stage process involving higher Landau levels. Although the available estimates of the collision rate are deficient in several ways, it appears that the rate is too low for electron-electron colli...

  6. Perimeter safeguards techniques for uranium-enrichment plants

    International Nuclear Information System (INIS)

    In 1972, a working group of the International Atomic Energy Agency identified a goal to develop and evaluate perimeter safeguards for uranium isotope enrichment plants. As part of the United State's response to that goal, Los Alamos Detection and Verification personnel studied gamma-ray and neutron emissions from uranium hexafluoride. They developed instruments that use the emissions to verify uranium enrichment and to monitor perimeter personnel and shipping portals. Unattended perimeter monitors and hand-held verification instruments were evaluated in field measurements and, when possible, were loaned to enrichment facilities for trials. None of the seven package monitoring techniques that were investigated proved entirely satisfactory for an unattended monitor. They either revealed proprietary information about centrifuge design or were subject to interference by shielding materials that could be present in a package. Further evaluation in a centrifuge facility may help in developing an acceptable attended package monitor. 34 figures, 9 tables

  7. Development of uranium milling and conversion

    International Nuclear Information System (INIS)

    The development and improvement of uranium milling and refining producing uranium tetrafluoride from ores by the wet process, without producing yellowcake as an intermediate product, have been carried out for over ten years with a small pilot plant (50 t-ore/day). In the past several years, a process for converting uranium tetrafluoride into hexafluoride has been developed successfully. To develop the process further, the construction of an integrated milling and conversion pilot plant (200 t-U/year) started in 1979 and was completed in 1981. This new plant has two systems of solvent extraction using tri-noctylamine: one of the systems treats the pregnant solution (uranyl sulphate) by heap-leaching followed by ion exchange, and the other treats the uranyl sulphate solution by dissolving imported yellowcake. The uranium loading solvents from the two systems are stripped with hydrochloric acid solution to obtain the concentrated uranium solution containing 100 g-U/1. Uranyl sulphate solution from the stripping circuit is reduced to a uranous sulphate solution by the electrolytic method. In a reduction cell, uranyl sulphate solution and dilute sulphuric acid are used respectively as catholyte and anolyte, and a cation exchange membrane is used to prevent re-oxidation of the uranous sulphate. In the following hydrofluorination step, uranium tetrafluoride, UF4.1-1.2H2O (particle size: 50-100μ), is produced continuously as the precipitate in an improved reaction vessel, and this makes it possible to simplify the procedures of liquid-solid separation, drying and granulation. The uranium tetrafluoride is dehydrated by heating to 3500C in an inert gas flow. The complete conversion from UF4 into UF6 is achieved by a fluidized-bed reactor and a high value of utilization efficiency of fluorine, over 99.9 percent, is attained at about 4000C. (author)

  8. Reduction of Rhizoctonia bare patch win wheat with barley rotations.

    Science.gov (United States)

    Rhizoctonia bare patch caused by Rhizoctonia solani AG-8 is a major fungal root disease in no-till cropping systems. In an 8-year experiment comparing various dryland no-till cropping systems near Ritzville, Washington, Rhizoctonia bare patch first appeared in year 3 and continued through year 8. ...

  9. Hydrodynamic behavior of a bare rod bundle

    International Nuclear Information System (INIS)

    The temperature distribution within the rod bundle of a nuclear reactor is of major importance in nuclear reactor design. However temperature information presupposes knowledge of the hydrodynamic behavior of the coolant which is the most difficult part of the problem due to complexity of the turbulence phenomena. In the present work a 2-equation turbulence model--a strong candidate for analyzing actual three dimensional turbulent flows--has been used to predict fully developed flow of infinite bare rod bundle of various aspect ratios (P/D). The model has been modified to take into account anisotropic effects of eddy viscosity. Secondary flow calculations have been also performed although the model seems to be too rough to predict the secondary flow correctly. Heat transfer calculations have been performed to confirm the importance of anisotropic viscosity in temperature predictions. All numerical calculations for flow and heat have been performed by two computer codes based on the TEACH code. Experimental measurements of the distribution of axial velocity, turbulent axial velocity, turbulent kinetic energy and radial Reynolds stresses were performed in the developing and fully developed regions. A 2-channel Laser Doppler Anemometer working on the Reference mode with forward scattering was used to perform the measurements in a simulated interior subchannel of a triangular rod array with P/D = 1.124. Comparisons between the analytical results and the results of this experiment as well as other experimental data in rod bundle array available in literature are presented. The predictions are in good agreement with the results for the high Reynolds numbers

  10. Czechoslovak uranium

    International Nuclear Information System (INIS)

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

  11. Reprocessed uranium handling at Siberian Group of Chemical Enterprises

    International Nuclear Information System (INIS)

    This paper describes the experience of treating reprocessed uranium (RepU) at the Siberian Group of Chemical Enterprises (SGChE). SGChE is a nuclear fuel cycle production center. It has been working with nuclear technologies for more than 10 years. The SGChE's production is shipped both into the Russian Federation’s market and the international market. SGChE has been active on the international enrichment services market since 1993. The experience of processing RepU at SGChE includes the following activities: the purification at the radiochemical plant of spent slightly irradiated fuel from two commercial reactors operated by SGChE operated reactors and also RepU from power reactors, the conversion of uranium with up to 1% U235 into hexafluoride at the conversion plant, and the enrichment of uranium hexafluoride with up to 5% U235 using the gas centrifuge equipment of the enrichment plant. In 1992, the SGChE started the commercial-scale conversion and enrichment of RepU derived from spent power reactor fuel imported from France. Over seven years, SGChE processed a total of about 1700 tonnes RepU. The SGChE has capacities to process up to 1500 tonnes of RepU per year with further rendering enrichment services totalling about 1 million SWU. (author)

  12. Atmospheric Sulfur Hexafluoride: Measurements and Emission Estimates from 1970 - 2008

    Science.gov (United States)

    Rigby, M. L.; Prinn, R. G.; Muhle, J.; Miller, B. R.; Dlugokencky, E. J.; Krummel, P. B.; Steele, L. P.; Fraser, P. J.; Leist, M.; Weiss, R. F.; Harth, C. M.; O'Doherty, S. J.; Greally, B. R.; Simmonds, P. G.; Derek, N.; Vollmer, M. K.; Kim, J.; Kim, K.; Porter, L. W.

    2009-12-01

    We present an air history of atmospheric sulfur hexafluoride (SF6) from the early 1970s through 2008. During this period, concentrations of this extremely potent and long-lived greenhouse gas have increased by more than an order of magnitude, and its growth has accelerated in recent years. In this study, historical concentrations are determined from archived air samples measured on the Advanced Global Atmospheric Gases Experiment (AGAGE) ‘Medusa’ gas chromatography/mass spectrometry system. These data are combined with modern high-frequency measurements from the AGAGE and National Oceanic and Atmospheric Administration (NOAA) in situ networks and ˜weekly samples from the NOAA flask network, to produce a unique time series with increasing global coverage spanning almost four decades. Using the three-dimensional chemical transport Model for Ozone and Related Tracers (MOZART v4.5) and a discrete Kalman filter, we derive estimates of the annual emission strength of SF6 on hemispheric scales from 1970 - 2004 and on continental scales from 2004 - 2008. Our emission estimates are compared to the recently compiled Emissions Database for Global Atmospheric Research (EDGAR v4), and emissions reported under the United Nations Framework Convention on Climate Change (UNFCCC). The cause of the recent growth rate increase is also investigated, indicating that the origin of the required emissions rise is likely to be South-East Asia.

  13. Depleted uranium storage and disposal trade study: Summary report

    International Nuclear Information System (INIS)

    The objectives of this study were to: identify the most desirable forms for conversion of depleted uranium hexafluoride (DUF6) for extended storage, identify the most desirable forms for conversion of DUF6 for disposal, evaluate the comparative costs for extended storage or disposal of the various forms, review benefits of the proposed plasma conversion process, estimate simplified life-cycle costs (LCCs) for five scenarios that entail either disposal or beneficial reuse, and determine whether an overall optimal form for conversion of DUF6 can be selected given current uncertainty about the endpoints (specific disposal site/technology or reuse options)

  14. Depleted uranium storage and disposal trade study: Summary report

    Energy Technology Data Exchange (ETDEWEB)

    Hightower, J.R.; Trabalka, J.R.

    2000-02-01

    The objectives of this study were to: identify the most desirable forms for conversion of depleted uranium hexafluoride (DUF6) for extended storage, identify the most desirable forms for conversion of DUF6 for disposal, evaluate the comparative costs for extended storage or disposal of the various forms, review benefits of the proposed plasma conversion process, estimate simplified life-cycle costs (LCCs) for five scenarios that entail either disposal or beneficial reuse, and determine whether an overall optimal form for conversion of DUF6 can be selected given current uncertainty about the endpoints (specific disposal site/technology or reuse options).

  15. Fluorination of uranium oxides in an engineering scale of fluidized bed

    International Nuclear Information System (INIS)

    In the R and D program for the reprocessing by fluoride volatility process, batch and semi-continuous fluorination have been studied using uranium oxides with or without nonradioactive fission products. A 3 inch-phi fluidized bed was used in obtaining the engineering fluorination date and also handling techniques for kilogram quantities of fluorine and uranium hexafluoride. Described are the equipment system and their technical experiences, mock-up experiments for the determination of fluidization conditions, fluorination rate and F2 utilization, and developments of in-line gas analyzers such as gas chromatograph and thermal conductivity cell for F2 and/or UF6. (auth.)

  16. Reprocessed uranium experience and UK options for NDA and Springfields Fuels Limited

    International Nuclear Information System (INIS)

    The Nuclear Decommissioning Authority (NDA) is the owner of over 20 000 t U of uranium arising from the reprocessing of Magnox fuel, known in the United Kingdom (UK) as Magnox Depleted Uranium (MD U). This material is stored in the form of uranium trioxide (UO3) at the NDA’s Capenhurst site. The NDA Strategy, published in March 2006, indicated that solutions to deal with MD U would be sought and that NDA would engage with the UK Government and UK Stakeholders to consider the most appropriate management strategies for uranic material. Springfields Fuels Limited (SFL), currently operated by Westinghouse, has recycled over 15 000 t U of MD U reprocessed uranium though its manufacturing facilities in production campaigns between the 1970s and the early 1990s. UO3 was converted to uranium tetrafluoride (UF4) in reduction and hydrofluorination kilns before being converted to uranium hexafluoride in the now decommissioned UF6 plants. Following enrichment, the UF6 was converted to uranium dioxide (UO2) via the integrated dry route kiln process and manufactured into fuel assemblies for the UK’s advanced gas-cooled reactors (AGR), operated by British Energy (BE). SFL has also demonstrated conversion of limited quantities of oxide reprocessed product. The paper provides details of reprocessed uranium stocks in the UK, NDA’s stakeholder engagement and reviews SFL’s experience from recycling uranium at Springfields which can help contribute to finding optimal solutions for UK reprocessed uranium issues. (author)

  17. Environmental impacts of options for disposal of depleted uranium tetrafluoride (UF4)

    International Nuclear Information System (INIS)

    The U.S. Department of Energy (DOE) evaluated options for managing its depleted uranium hexafluoride (UF6) inventory in the Programmatic Environmental Impact Statement for the Long-Term Management and Use of Depleted Uranium Hexafluoride (PEIS) of April 1999. Along with the impacts from other management options, the PEIS discussed the environmental impacts from the disposal of depleted uranium oxide, which could result from the chemical conversion of depleted UF6. It has been suggested that the depleted UF6 could also be converted to uranium tetrafluoride (UF4) and disposed of. This report considers the potential environmental impacts from the disposal of DOE's depleted UF6 inventory after its conversion to UF4. The impacts were evaluated for the same three disposal facility options that were considered in the PEIS for uranium oxide: shallow earthen structures, belowground vaults, and mines. They were evaluated for a dry environmental setting representative of the western United States. To facilitate comparisons and future decision making, the depleted UF4 disposal analyses performed and the results presented in this report are at the same level of detail as that in the PEIS

  18. Uranium production

    International Nuclear Information System (INIS)

    The alltime high for uranium concentrate production is expected to be reached in 1980. The average grade of ore fed to process will be up about 10% from last year. Some curtailments in uranium processing were announced, but three new processing plants began production in 1980. The prospects for 1981 are not as encouraging. The continuation of low prices and slow demand for U3O8 are expected to be reflected in a significant reduction in overall production and in the postponement of some plans for expansion and construction of uranium processing facilities. Increases in production capacity will occur when Plateau Resource's 750 TPD mill at Ticaboo, Utah, starts up early next year, and additional production of byproduct uranium is expected from western phosphate operations and from the southern states. These increases in capacity, however, will not offset the cutbacks in uranium processing already in force together with the additional curtailments anticipated during the course of 1981

  19. Uranium enrichment

    International Nuclear Information System (INIS)

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

  20. EAARL Coastal Topography--Pearl River Delta 2008: Bare Earth

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare earth elevation map (also known as a Digital Elevation Model, or DEM) of the Pearl River Delta in Louisiana and Mississippi was produced from remotely...

  1. EAARL Topography-Vicksburg National Millitary Park 2008: Bare Earth

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare earth elevation map (also known as a Digital Elevation Model, or DEM) of the Vicksburg National Military Park in Mississippi was produced from remotely...

  2. EAARL Coastal Topography--Chandeleur Islands, Louisiana, 2010: Bare Earth

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare-earth digital elevation map (also known as a Digital Elevation Model, or DEM) of a portion of the Chandeleur Islands, Louisiana, was produced from remotely...

  3. EAARL Bare Earth Topography-Fire Island National Seashore

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare earth elevation map (also known as a Digital Elevation Model or DEM) of Fire Island National Seashore was produced from remotely-sensed,...

  4. EAARL Coastal Topography - Northern Gulf of Mexico, 2007: Bare earth

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare earth elevation map (also known as a Digital Elevation Model, or DEM) of the northern Gulf of Mexico barrier islands and Naval Live Oaks was produced from...

  5. EAARL Coastal Topography--Northeast Barrier Islands 2007: Bare Earth

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare earth elevation map (also known as a Digital Elevation Model, or DEM) of the northeast coastal barrier islands in New York and New Jersey was produced from...

  6. Environmental monitoring program design for uranium refining and conversion operations

    International Nuclear Information System (INIS)

    The objective of this study was to develop recommendations for the design of environmental monitoring programs at Canadian uranium refining and conversion operations. In order to develop monitoring priorities, chemical and radioactive releases to the air and water were developed for reference uranium refining and conversion facilities. The relative significance of the radioactive releases was evaluated through a pathways analysis which estimated dose to individual members of the critical receptor group. The effects of chemical releases to the environment were assessed by comparing predicted air and water contaminant levels to appropriate standards or guidelines. For the reference facilities studied, the analysis suggested that environmental effects are likely to be dominated by airborne release of both radioactive and nonradioactive contaminants. Uranium was found to be the most important radioactive species released to the air and can serve as an overall indicator of radiological impacts for any of the plants considered. The most important nonradioactive air emission was found to be fluoride (as hydrogen fluoride) from the uranium hexafluoride plant. For the uranium trioxide and uranium dioxide plants, air emissions of oxides of nitrogen were considered to be most important. The study recommendations for the design of an environmental monitoring program are based on consideration of those factors most likely to affect local air and water quality, and human radiation exposure. Site- and facility-specific factors will affect monitoring program design and the selection of components such as sampling media, locations and frequency, and analytical methods

  7. Internal dosimetry for uranium fuel manufacture at BNFL

    International Nuclear Information System (INIS)

    At its Springfields Works, near Preston, UK BNFL manufactures uranium fuels and fuel intermediates, in a range of chemical and metallurgical processes. Uranium ore concentrate is converted to uranium metal for the Magnox reactors, uranium hexafluoride (UF6) to uranium dioxide (UO2) for AGR and other oxide reactors, and various intermediate products are produced to meet customer requirements. Thus, uranium compounds with biological retention periods ranging from days (UF6) to years (UO2) are handled on multi-hundred, or thousand, tonne per year scales. Control and minimisation of workforce exposure is exercised primarily by engineered methods (e.g. total enclosures and high integrity plant), backed up by use of respiratory and other protective equipment. A high profile is given to good standards of housekeeping. Assessment of intake is by methods approved by HSE (NII) in the Approved Laboratory Statement on internal dosimetry. The principal method is assessment by use of continuous air sampling combined with occupancy. This is back up by routine personal air sampling (PAS) in selected relevant areas in which ceramic UO2 is handled. Further assurance is provided by programmed PAS in other areas and by systematic, and routine, urinalysis and whole-body monitoring of all relevant members of the workforce. The results of the above are presented in detail. (Author)

  8. Bare and effective fluid description in brane world cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Norman [Universidad de Santiago, Departamento de Fisica, Facultad de Ciencia, Casilla 307, Santiago (Chile); Lepe, Samuel; Saavedra, Joel [Pontificia Universidad Catolica de Valparaiso, Instituto de Fisica, Casilla 4950, Valparaiso (Chile); Pena, Francisco [Universidad de La Frontera, Departamento de Ciencias Fisicas, Facultad de Ingenieria, Ciencias y Administracion, Avda. Francisco Salazar 01145, Casilla 54-D, Temuco (Chile)

    2010-03-15

    An effective fluid description, for a brane world model in five dimensions, is discussed for both signs of the brane tension. We found several cosmological scenarios where the effective equation differs widely from the bare equation of state. For universes with negative brane tension, with a bare fluid satisfying the strong energy condition, the effective fluid can cross the barrier {omega} {sub eff}=-1. (orig.)

  9. SULFUR HEXAFLUORIDE TREATMENT OF USED NUCLEAR FUEL TO ENHANCE SEPARATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Gray, J.; Torres, R.; Korinko, P.; Martinez-Rodriguez, M.; Becnel, J.; Garcia-Diaz, B.; Adams, T.

    2012-09-25

    Reactive Gas Recycling (RGR) technology development has been initiated at Savannah River National Laboratory (SRNL), with a stretch-goal to develop a fully dry recycling technology for Used Nuclear Fuel (UNF). This approach is attractive due to the potential of targeted gas-phase treatment steps to reduce footprint and secondary waste volumes associated with separations relying primarily on traditional technologies, so long as the fluorinators employed in the reaction are recycled for use in the reactors or are optimized for conversion of fluorinator reactant. The developed fluorination via SF{sub 6}, similar to the case for other fluorinators such as NF{sub 3}, can be used to address multiple fuel forms and downstream cycles including continued processing for LWR via fluorination or incorporation into a aqueous process (e.g. modified FLUOREX) or for subsequent pyro treatment to be used in advanced gas reactor designs such metal- or gas-cooled reactors. This report details the most recent experimental results on the reaction of SF{sub 6} with various fission product surrogate materials in the form of oxides and metals, including uranium oxides using a high-temperature DTA apparatus capable of temperatures in excess of 1000{deg}C . The experimental results indicate that the majority of the fission products form stable solid fluorides and sulfides, while a subset of the fission products form volatile fluorides such as molybdenum fluoride and niobium fluoride, as predicted thermodynamically. Additional kinetic analysis has been performed on additional fission products. A key result is the verification that SF{sub 6} requires high temperatures for direct fluorination and subsequent volatilization of uranium oxides to UF{sub 6}, and thus is well positioned as a head-end treatment for other separations technologies, such as the volatilization of uranium oxide by NF{sub 3} as reported by colleagues at PNNL, advanced pyrochemical separations or traditional full recycle

  10. Oralloy (93.2 235U) Bare Metal Annuli And Disks

    Energy Technology Data Exchange (ETDEWEB)

    Hummel, Andrew John [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-01

    A multitude of critical experiments with highly enriched uranium metal were conducted in the 1960s and 1970s at the Oak Ridge Critical Experiments Facility (ORCEF) in support of criticality safety operations at the Y-12 Plant. These experiments served to evaluate the storage, casting, and handling limits for the Y-12 Plant while also providing data for verification of different calculation methods and associated cross-sections for nuclear criticality safety applications. These included both solid cylinders and annuli of various diameters, interacting cylinders of various diameters, parallelepipeds, and reflected cylinders and annuli. The experiments described here involve a series of delayed critical stacks of bare oralloy HEU annuli and disks. Three of these experiments consist of stacking bare HEU annuli of varying diameters to obtain critical configurations. These annuli have nominal inner and outer diameters (ID/OD) including: 7 inches (") ID – 9" OD, 9" ID – 11" OD, 11" ID – 13" OD, and 13? ID – 15" OD. The nominal heights range from 0.125" to 1.5". The three experiments themselves range from 7" – 13", 7" – 15", and 9" – 15" in diameter, respectively. The fourth experiment ranges from 7" – 11", and along with different annuli, it also includes an 11" disk and several 7" diameter disks. All four delayed critical experiments were configured and evaluated by J. T. Mihalczo, J. J. Lynn, and D. E. McCarty from December of 1962 to February 1963 with additional information in their corresponding logbook.

  11. New Prototype Safeguards Technology Offers Improved Confidence and Automation for Uranium Enrichment Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Brim, Cornelia P.

    2013-04-01

    An important requirement for the international safeguards community is the ability to determine the enrichment level of uranium in gas centrifuge enrichment plants and nuclear fuel fabrication facilities. This is essential to ensure that countries with nuclear nonproliferation commitments, such as States Party to the Nuclear Nonproliferation Treaty, are adhering to their obligations. However, current technologies to verify the uranium enrichment level in gas centrifuge enrichment plants or nuclear fuel fabrication facilities are technically challenging and resource-intensive. NNSA’s Office of Nonproliferation and International Security (NIS) supports the development, testing, and evaluation of future systems that will strengthen and sustain U.S. safeguards and security capabilities—in this case, by automating the monitoring of uranium enrichment in the entire inventory of a fuel fabrication facility. One such system is HEVA—hybrid enrichment verification array. This prototype was developed to provide an automated, nondestructive assay verification technology for uranium hexafluoride (UF6) cylinders at enrichment plants.

  12. Recovery of valuable products in the raffinate of the uranium and thorium pilot-plant

    International Nuclear Information System (INIS)

    IPEN-CNEN/SP has being very active in refining yellowcake to pure ammonium diuranate which is converted to uranium trioxide, uranium dioxide, tetra - and hexafluoride in a sequential way. The technology of the thorium purification and its conversion to nuclear grade products has been a practice since several years as well. For both elements the major to be worked is the raffinate from the solvent extraction colum where and thorium are purified via TBP-varsol in pulsed columns. In this paper the actual processing technology is reviewed with special emphasis on the recovery of valuable products, mainly nitric acid and ammonium nitrate. Distilled nitric acid and the final sulfuric acid as residue are recycle. Ammonium nitrate from the precipitation of uranium diuranate is of good quality, being radioactivity and uranium - free, and recommended to be applied as fertilizer. In conclusion the main effort is to maximize the recycle and reuse of the above mentioned chemicals. (author)

  13. Separation of uranium isotopes by gas centrifugation

    International Nuclear Information System (INIS)

    The uranium isotope enrichment is studied by means of the countercurrent gas centrifuge driven by thermal convection. A description is given of (a) the transfer and purification of the uranium hexafluoride used as process gas in the present investigation; (b) the countercurrent centrifuge ZG3; (c) the system designed for the introduction and extraction of the process gas from the centrifuge; (d) the measurement of the process gas flow rate through the centrifuge; (e) the determination of the uranium isotopic abundance by mass spectrometry; (f) the operation and mechanical behavior of the centrifuge and (g) the isotope separation experiments, performed, respectively, at total reflux and with production of enriched material. The results from the separation experiments at total reflux are discussed in terms of the enrichment factor variation with the magnitude and flow profile of the countercurrent given by the temperature difference between the rotor covers. As far as the separation experiments with production are concerned, the discussion of their results is presented through the variation of the enrichment factor as a function of the flow rate, the observed asymmetry of the process and the calculated separative power of the centrifuge. (Author)

  14. Tramp uranium

    International Nuclear Information System (INIS)

    Many utilities have implemented a no leaker philosophy for fuel performance and actively pursue removing leaking fuel assemblies from their reactor cores whenever a leaking fuel assembly is detected. Therefore, the only source for fission product activity in the RCS when there are no leaking fuel assemblies is tramp uranium. A technique has been developed that strips uranium impurities from ZrCl4. Unless efforts are made to remove natural uranium impurities from reactor materials, the utilities will not be able to reduce the RCS specific 131I activity in PWRs to below the lower limit of ∼1.0 x 10-4 μCi/g

  15. Atmospheric Sulfur Hexafluoride: Sources, Sinks and Greenhouse Warming

    Science.gov (United States)

    Sze, Nien Dak; Wang, Wei-Chyung; Shia, George; Goldman, Aaron; Murcray, Frank J.; Murcray, David G.; Rinsland, Curtis P.

    1993-01-01

    Model calculations using estimated reaction rates of sulfur hexafluoride (SF6) with OH and 0('D) indicate that the atmospheric lifetime due to these processes may be very long (25,000 years). An upper limit for the UV cross section would suggest a photolysis lifetime much longer than 1000 years. The possibility of other removal mechanisms are discussed. The estimated lifetimes are consistent with other estimated values based on recent laboratory measurements. There appears to be no known natural source of SF6. An estimate of the current production rate of SF6 is about 5 kt/yr. Based on historical emission rates, we calculated a present-day atmospheric concentrations for SF6 of about 2.5 parts per trillion by volume (pptv) and compared the results with available atmospheric measurements. It is difficult to estimate the atmospheric lifetime of SF6 based on mass balance of the emission rate and observed abundance. There are large uncertainties concerning what portion of the SF6 is released to the atmosphere. Even if the emission rate were precisely known, it would be difficult to distinguish among lifetimes longer than 100 years since the current abundance of SF6 is due to emission in the past three decades. More information on the measured trends over the past decade and observed vertical and latitudinal distributions of SF6 in the lower stratosphere will help to narrow the uncertainty in the lifetime. Based on laboratory-measured IR absorption cross section for SF6, we showed that SF6 is about 3 times more effective as a greenhouse gas compared to CFC 11 on a per molecule basis. However, its effect on atmospheric warming will be minimal because of its very small concentration. We estimated the future concentration of SF6 at 2010 to be 8 and 10 pptv based on two projected emission scenarios. The corresponding equilibrium warming of 0.0035 C and 0.0043 C is to be compared with the estimated warming due to CO2 increase of about 0.8 C in the same period.

  16. The structure of Canada's uranium industry and its future market prospects

    International Nuclear Information System (INIS)

    Production of uranium in Canada began in the 1940s to supply the needs of US weapons development. After 1966 a growing demand for uranium for nuclear power production stimulated exploration, and since then the health of the Canadian uranium industry has been tied to the state of the nuclear power industry. Uranium exploration in Canada is carried out mainly by private enterprise, although the federal and two provincial governments compete through crown corporations. Seven companies produce ore, and six have processing plants. Expansion is underway at several existing operations, and some new projects are underway. The industry is strongly dependent on export markets; only about 15 percent of Canadian production is used in the country. There is one uranium refinery which produces UO2 powder for CANDU reactor fuel and UF6 for export. The uranium hexafluoride facility is being expanded. Federal government policy affects the uranium industry in the fields of regulation, ownership, safeguards, protection of the domestic industry, and international marketing. The short-term outlook for the industry is deteriorating, with declining uranium prices, but prospects seem considerably brighter in the longer term. Canada has about 12 percent of the world's uranium reserves, and is the second-largest producer. Discovery potential is believed to be excellent

  17. Preliminary results from sulfur hexafluoride and deuterated methane releases of December 10, 1975

    International Nuclear Information System (INIS)

    Multi-laboratory experiments were performed at the Savannah River Plant (SRP) during December 1975. Of all the experiments, the one involving the sulfur hexafluoride and deuterated methane on December 10 was the most extensive. This experiment tested the LLL-ARAC system and the relative effectiveness of several different tracers for atmospheric transport and diffusion studies. The goals of this test were: to determine whether sulfur hexafluoride, krypton-85, and deuterated methane tracers [methane-20 (12C2H4) and methane-21 (13C2H4)] give comparable results when they are released and sampled simultaneously; to study the transport and dispersion of the plume out to 100 km from the point source; to gain experience in release, sample processing, and analyzing these tracers; and to exercise the LLL-ARAC system. The comparisons of the relative effectiveness of the deuterated methane and sulfur hexafluoride as tracers indicated that the methane concentrations were a factor of 4 below the sulfur hexafluoride concentrations when normalized to consistent units. The 85Kr results differed from the other two tracers as a result of a difference time sequence of release

  18. Experimental study for the use of sulfur hexafluoride as dielectric gas in particle accelerators

    International Nuclear Information System (INIS)

    The sulfur hexafluoride is the better dielectric gas in the world. It is used in particle accelerator, power stations and high voltage transformators. This is a high stable gas, but when is used as dielectric is degraded in toxic and corrosive fluorides this degradation of sulfur hexafluoride is a function of the voltaic arc, crown effect, pressure, temperature and radiation. The purification of the sulfur fluoride permitted to work in safe form and without the risks as contaminant. The objective of the work is the development of a process for the separation of the wastes from the fabrication of sulphur fluoride and the products of degradation. This process used adsorbents when this gas is used as dielectric. The methodology employed was bibliography research, experimental design of the equipment, construction of the experimental equipment, selection and use of adsorbents, installation of the adsorption columns for the experimentation, flow of the sulfur hexafluoride through the adsorbents, searching of the fluoride hexafluoride before and after of the step through the adsorption columns and writing of the results. In base to the results we conclude that the process is good. The work could be advantage using chromatographic techniques with adequate standards. Is possible to extend the study using an additional number of adsorbents. (Author). 34 refs, 7 graphs, 3 tabs

  19. Uranium Market

    International Nuclear Information System (INIS)

    The main fuel component for commercial nuclear power reactors is Uranium. When compared to fossil fuels, it has a competitive edge due to factors such as economics and environmental conditions and in particular due to its international market availability. Uranium world demand reached to 67 320 tU in 2004, which was covered with additional sources. To project the uranium markets behavior requires to know and to accept some conditions tied to the demand, such as the electrical world consumption, the greenhouse effect; water desalination, production of hydrogen, industrial heat, the innovative development of nuclear reactors, and the average time of 10 years between the beginning of exploration programs and definition of deposits, which it owes mainly to the difficulty of achieving the legal, environmental and local community authorizations, to open new mining centers. Uranium market future projections, made by IAEA experts in 2001, that considered middle and high demand scenarios, concluded that cumulatively to year 2050, with regard to demand it will be required 5.4 and 7.6 million tons of uranium respectively, and with regard to the uranium price, it should present a sustained increase. In the last years the situation of the uranium market has changed dramatically. In August 2006 the price of uranium reached to USD 106/kgU in the spot market, surpassing all the made projections. The increase in price that has stayed in rise in the last five years is reactivating the prospection and exploration efforts anywhere in the world, and competition between prospective areas of potential resources mainly in less explored territories

  20. Uranium, depleted uranium, biological effects

    International Nuclear Information System (INIS)

    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)

  1. Uranium loans

    International Nuclear Information System (INIS)

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

  2. Measurement system analysis (MSA) of the isotopic ratio for uranium isotope enrichment process control

    International Nuclear Information System (INIS)

    Currently, one of the stages in nuclear fuel cycle development is the process of uranium isotope enrichment, which will provide the amount of low enriched uranium for the nuclear fuel production to supply 100% Angra 1 and 20% Angra 2 demands. Determination of isotopic ration n(235U)/n(238U) in uranium hexafluoride (UF6 - used as process gas) is essential in order to control of enrichment process of isotopic separation by gaseous centrifugation cascades. The uranium hexafluoride process is performed by gas continuous feeding in separation unit which uses the centrifuge force principle, establishing a density gradient in a gas containing components of different molecular weights. The elemental separation effect occurs in a single ultracentrifuge that results in a partial separation of the feed in two fractions: an enriched on (product) and another depleted (waste) in the desired isotope (235UF6). Industrias Nucleares do Brasil (INB) has used quadrupole mass spectrometry (QMS) by electron impact (EI) to perform isotopic ratio n(235U)/n(238U) analysis in the process. The decision of adjustments and change te input variables are based on the results presented in these analysis. A study of stability, bias and linearity determination has been performed in order to evaluate the applied method, variations and systematic errors in the measurement system. The software used to analyze the techniques above was the Minitab 15. (author)

  3. Uranium resources and uranium supply

    International Nuclear Information System (INIS)

    The availability of natural uranium is currently considered unproblematic. Out of concern about the sufficient availability of uranium, an international working group of OECD-NEA, in which the Federal Office for Geosciences and Resources (BGR) participates as a German partner, has conducted analyses of uranium availability since 1965. Its findings are published biannually in the so-called 'Red Book', 'Uranium, Resources, Production, and Demand'. Changes in the political situation worldwide have profoundly influenced the military importance of uranium and thus also greatly improved its accessibility. As a consequence, there was a decline in production in the nineties from approx. 57,000 t of U in 1989 to, at present (2001), approx. 35,000 t annually. Estimates of the worldwide requirement of natural uranium in 2015 range between approx. 55,000 t and 80,000 t of U, because of the unforeseeable extent of the use of nuclear power, as against approx. 63,000 t of U in 2001. The most recent statistics published in the 1999 Red Bock show low-cost reserves (up to Dollar 40 per kg of U) of 1325 million t, and 2234 t of uranium at extraction costs of up to t Dollar 80 per kg. This indicates a statistical range of reserves of approx. 35 years. It should be noted that these figures are snapshots of a dynamic system. A resumption of extensive exploration and technical developments could greatly influence the resource situation. In the nineties, for instance, there is a net increase in uranium reserves of approx. 700,000 t of U as a consequence of exploration activities. (orig.)

  4. Semantic coherence in English accusative-with-bare-infinitive constructions

    DEFF Research Database (Denmark)

    Jensen, Kim Ebensgaard

    2013-01-01

    Drawing on usage-based cognitively oriented construction grammar, this paper investigates the patterns of coattraction of items that appear in the two VP positions (the VP in the matrix clause, and the VP in the infinitive subordinate clause) in the English accusative-with-bare-infinitive constru......Drawing on usage-based cognitively oriented construction grammar, this paper investigates the patterns of coattraction of items that appear in the two VP positions (the VP in the matrix clause, and the VP in the infinitive subordinate clause) in the English accusative......-with-bare-infinitive construction. The main methodological framework is that of covarying collexeme analysis, which, through statistical corpus analysis, allows for the analyst to address the semantics of a construction. Using this method on data from the BNC, the ultimate purpose of the paper is to address the underlying semantic...... relations of English accusatives-with-bare-infinitives through the relations of semantic coherence between the two VPs....

  5. Fluorination of uranium and plutonium dioxides in flame tower reactors

    International Nuclear Information System (INIS)

    Fluorination of uranium and plutonium dioxides by fluorine is discussed for the flame tower reactor, which is one of possible reactors is FLUOREX process, a hybrid reprocessing combining a fluoride volatility process and a solvent extraction. A reaction model for a shrinking particle with an un-reacted shrinking core is applied to the fluorination of plutonium dioxide and the reaction rate constants are determined in low temperature range around 400degC using the reported kinetic data [Iwasaki et al., J. Nucl. Sci. Technol., 11, 403 (1974)]. The determined rate equations are used to analyze the fluorination of uranium and plutonium dioxides in the high temperature range (800-1,200degC), where the flame tower reactor is operated. For uranium dioxides the diffusion of fluorine to the particle controls the overall fluorination reaction, and the model can predict the recovery of uranium to the product of uranium hexafluoride. For plutonium dioxides, however, the recoveries of plutonium calculated by the presented model do not agree with the experimental recoveries. It is suggested that the reaction mechanism for the fluorination of plutonium dioxide in the high temperature range is different from that in the low temperature range. (author)

  6. Uranium mining

    International Nuclear Information System (INIS)

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

  7. A proposed bare tether experiment on board a sounding rocket

    OpenAIRE

    Fujii, Hironori; OYAMA, Kohichiro; Sasaki, Susumu; Yamagiwa, Yoshiki; Cho, Mengu; Sanmartín Losada, Juan Ramón; Charro, Mario; Heide, Erik J. van der; Kruijff, Michiel; Lebreton, Jean-Pierre; Hilgers, Alain

    2005-01-01

    A sounding rocket experiment is proposed to carry out two experiments by the conductive bare-tether; 1) the test of the OML (Orbital-Motion-Limited) theory to collect electron, and II) the test of techniques to determine (neutral) density profile in critical E-layer. The main driver of the mission is provide a space tether technology experiment in low-Earth-Orbit (LEO) deploying a long tape tether in space and verify the performance of the bare electrodynamic tape tether. The sounding rocket ...

  8. Uranium enrichment

    International Nuclear Information System (INIS)

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

  9. The development of the uranium and nuclear industry in South Africa, 1945 - 1970 : a historical study

    International Nuclear Information System (INIS)

    This thesis traces the historical development of nuclear research in South Africa between 1945 and 1970, starting with the efforts of metallurgists of South Africa and the Allied Nations to extract uranium from the gold ores of the Witwatersrand. During the 1950's seventeen uranium extraction plants formed a very important part of the country's industrial activity. The prospect of using South African uranium for nuclear power production (in the Western Cape area), led to the Atomic Energy Research and Development Programme investigation into nuclear energy production in South Africa. The programme provided for the refining of uranium for nuclear fuel, the establishment of a nuclear research centre at Pelindaba, the acquisition of a research reactor, and facilities for nuclear reactor research and uranium enrichment experiments. The two major projects that were initiated in the 1960's were the Pelinduna nuclear reactor project and experimentation on the vortex tube method for uranium enrichment (the Gas Cooling Project). An Investigation Committee was appointed by the Government to assess the viability of a pilot uranium enrichment plant. In 1970 it was announced that a process had been developed that was a combination of the separating element using uranium hexafluoride in hydrogen as the process fluid and a new cascade technique. 331 refs., 19 figs

  10. Uranium bombs

    Science.gov (United States)

    DeGroot, Gerard

    2009-11-01

    Enrico Fermi was a brilliant physicist, but he did occasionally get things wrong. In 1934 he famously bombarded a sample of uranium with neutrons. The result was astounding: the experiment had, Fermi concluded, produced element 93, later called neptunium. The German physicist Ida Noddack, however, came to an even more spectacular conclusion, namely that Fermi had split the uranium nucleus to produce lighter elements. Noddack's friend Otto Hahn judged that idea preposterous and advised her to keep quiet, since ridicule could ruin a female physicist. She ignored that advice, and was, indeed, scorned.

  11. Bare Higgs mass and potential at ultraviolet cutoff

    CERN Document Server

    Hamada, Yuta; Oda, Kin-ya

    2013-01-01

    We first review the current status of the top mass determination paying attention to the difference between the MS-bar and pole masses. Then we present our recent result on the bare Higgs mass at a very high ultraviolet cutoff scale.

  12. BARE retrotransposons are translated and replicated via distinct RNA pools.

    Directory of Open Access Journals (Sweden)

    Wei Chang

    Full Text Available The replication of Long Terminal Repeat (LTR retrotransposons, which can constitute over 80% of higher plant genomes, resembles that of retroviruses. A major question for retrotransposons and retroviruses is how the two conflicting roles of their transcripts, in translation and reverse transcription, are balanced. Here, we show that the BARE retrotransposon, despite its organization into just one open reading frame, produces three distinct classes of transcripts. One is capped, polyadenylated, and translated, but cannot be copied into cDNA. The second is not capped or polyadenylated, but is destined for packaging and ultimate reverse transcription. The third class is capped, polyadenylated, and spliced to favor production of a subgenomic RNA encoding only Gag, the protein forming virus-like particles. Moreover, the BARE2 subfamily, which cannot synthesize Gag and is parasitic on BARE1, does not produce the spliced sub-genomic RNA for translation but does make the replication competent transcripts, which are packaged into BARE1 particles. To our knowledge, this is first demonstration of distinct RNA pools for translation and transcription for any retrotransposon.

  13. Basic science of nuclear medicine the bare bone essentials

    CERN Document Server

    Lee, Kai H

    2015-01-01

    Through concise, straightforward explanations and supporting graphics that bring abstract concepts to life, the new Basic Science of Nuclear Medicine—the Bare Bone Essentials is an ideal tool for nuclear medicine technologist students and nuclear cardiology fellows looking for an introduction to the fundamentals of the physics and technologies of modern day nuclear medicine.

  14. Evaluation of Bare Ground on Rangelands using Unmanned Aerial Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Robert P. Breckenridge; Maxine Dakins

    2011-01-01

    Attention is currently being given to methods that assess the ecological condition of rangelands throughout the United States. There are a number of different indicators that assess ecological condition of rangelands. Bare Ground is being considered by a number of agencies and resource specialists as a lead indicator that can be evaluated over a broad area. Traditional methods of measuring bare ground rely on field technicians collecting data along a line transect or from a plot. Unmanned aerial vehicles (UAVs) provide an alternative to collecting field data, can monitor a large area in a relative short period of time, and in many cases can enhance safety and time required to collect data. In this study, both fixed wing and helicopter UAVs were used to measure bare ground in a sagebrush steppe ecosystem. The data were collected with digital imagery and read using the image analysis software SamplePoint. The approach was tested over seven different plots and compared against traditional field methods to evaluate accuracy for assessing bare ground. The field plots were located on the Idaho National Laboratory (INL) site west of Idaho Falls, Idaho in locations where there is very little disturbance by humans and the area is grazed only by wildlife. The comparison of fixed-wing and helicopter UAV technology against field estimates shows good agreement for the measurement of bare ground. This study shows that if a high degree of detail and data accuracy is desired, then a helicopter UAV may be a good platform. If the data collection objective is to assess broad-scale landscape level changes, then the collection of imagery with a fixed-wing system is probably more appropriate.

  15. Nanosecond discharge in sulfur hexafluoride and the generation of an ultrashort avalanche electron beam

    Science.gov (United States)

    Baksht, E. Kh.; Burachenko, A. G.; Erofeev, M. V.; Lomaev, M. I.; Rybka, D. V.; Sorokin, D. A.; Tarasenko, V. F.

    2008-06-01

    A discharge in the presence of a nonuniform electric field and the generation of an ultrashort avalanche electron beam (UAEB) are studied in the insulating gas SF6 at the pressures 0.01 2.50 atm. High-voltage nanosecond pulses (about 150 and 250 kV) and the voltage pulses with an amplitude of 25 kV and a duration of tens of nanoseconds are applied across the gap. An electron beam is obtained behind the AlBe foil with a thickness of 45 μm at a sulfur hexafluoride pressure in a gas-filled diode of up to 2 atm. It is demonstrated that, at relatively high pressures (greater than 1 atm) and in the presence of high-voltage nanosecond pulses across the gap, the UAEB pulse FWHM increases. The spectra of the diffuse and contracted discharges in sulfur hexafluoride are measured.

  16. Macro kinetics of uranium or rare earth oxides fluorination in vortex flows

    International Nuclear Information System (INIS)

    Highly efficient vortex-type apparatuses with low flow rates of fluorine and oxide solid phase are of great interest for preparation of uranium hexafluoride and rare earth fluorides from their oxides. For obtaining initial data on designing the apparatuses the fields of local rates of the solid phase particles in the vortex flow of a model apparatus 4.8x10-2 m in diameter are identified and numerical studies of macro kinetics of uranium oxide fluorination in fluorine vortex flow are conducted. It is shown that uranium oxide particles actually do not burn out in kinetic mode of the process, being largely burnt out in diffusion mode. About 60-70% of total time of the particle burning falls on the stage of quasistationary warming up of the mixture

  17. Criticality sensitivity analysis of uranium deposits in large-diameter piping

    International Nuclear Information System (INIS)

    The former Oak Ridge Gaseous Diffusion Plant (now referred to as the K-25 site) operated between 1945 and 1985 to supply the U.S. Department of Defense with enriched uranium. Throughout its operation, the gaseous diffusion process resulted in the accumulation of residual deposits of uranium along the inner surface areas of the process piping and equipment. The deposits are primarily uranyl fluoride (UO2F2), which formed when uranium hexafluoride (UF6) reacted with moisture from in-leakage of air. Because many of these deposits have greater than minimum critical mass and are in an unfavorable geometry, they pose a potential nuclear criticality accident hazard. As part of the U.S. Department of Energy mission to decontaminate and decommission surplus facilities at the K-25 site, the Deposit Removal Project has been tasked with removing these deposits

  18. Radiological safety aspects of uranium fuel fabrication facilities at Nuclear Fuel Complex, Hyderabad

    International Nuclear Information System (INIS)

    The Health Physics Division of the Bhabha Atomic Research Centre is operating a Health Physics Unit at Nuclear Fuel Complex, Hyderabad which carried out radiological, industrial hygiene and environmental surveillances. Nuclear Fuel Complex has two batteries of plants - one for natural UO2 fuel bundles for Pressurised Heavy Water Reactors (PHWRs) and the other for enriched UO2 fuel assemblies for Boiling Water Reactor (BWR) in the country. For natural UO2 fuel the Uranium Oxide Plant (UOP) converts magnesium diuranate to UO2 powder. The Ceramic Fuel Fabrication Plant (CFFP) processes the UO2 powder to dense sintered UO2 pellets and further to fuel assemblies for PHWR. The Enriched Uranium Oxide Plant (EUOP) starts with uranium hexa-fluoride and converts to UO2 powder and Enriched Fuel Fabrication Plant (EFFP) processes the UO2 powder to sintered pellets and fuel assemblies for BWR

  19. Development and technical implementation of the separation nozzle process for enrichment of uranium 235

    International Nuclear Information System (INIS)

    The separation nozzle process for the enrichment of uranium-235 has been developed at the Karlsruhe Nuclear Research Center as an alternative to the gaseous diffusion and centrifuge process. The separation of uranium isotopes is achieved by the deflection of a jet of uranium hexafluoride mixed with hydrogen. Since 1970, the German company of STEAG, has been involved in the technological development and commercial implementation of the nozzle process. In 1975, the Brazilian company of NUCLEBRAS, and the German company of Interatom, joined the effort. The primary objective of the common activity is the construction of a separation nozzle demonstration plant with an annual capacity of about 200 000 SWU and the development of components of a commercial plant. The paper covers the most important steps in the development and the technical implementation of the process. (orig.)

  20. Extraction of polychlorinated biphenyl with supercritical carbon dioxide, sulfur hexafluoride and subcritical water.

    Science.gov (United States)

    Pross, S; Gau, W; Wenclawiak, B W

    2000-05-01

    In the extraction of spiked PCB from soil, three extracting fluids were investigated: supercritical carbon dioxide (CO2), supercritical sulfur hexafluoride (SF6) and subcritical water. Among the tested fluids SF6 appeared to be appropriate especially for the extraction of low polar PCB. CO2 and water were found to be suitable for the quantitative extraction of all PCB. Water was judged as the best because of its low price, good availability and environmental safety. PMID:11227442

  1. Density Functional Study of Sulfur Hexafluoride (SF6) and its Hydrogen Derivatives

    OpenAIRE

    Piechota, Jacek; Bruska, Marta Kinga

    2008-01-01

    Abstract Density functional study has been performed for group of compounds derived from sulfur hexafluoride (SF6) by consecutively substituting fluorine with hydrogen. SF6 is widely used as the insulating gas in the electrical industry and is recognized as one of the greenhouse gases with extraordinary global warming potential. The aim of the present study is to look for potential industrial alternatives to SF6 as well as to examine mechanisms that can contribute to its faster atm...

  2. A Sulfur Hexafluoride Sensor Using Quantum Cascade and CO2 Laser-Based Photoacoustic Spectroscopy

    OpenAIRE

    Helion Vargas; Delson Schramm; Marcelo da Silva; Mila Rocha; Marcelo Sthel; Guilherme Lima; András Miklós

    2010-01-01

    The increase in greenhouse gas emissions is a serious environmental problem and has stimulated the scientific community to pay attention to the need for detection and monitoring of gases released into the atmosphere. In this regard, the development of sensitive and selective gas sensors has been the subject of several research programs. An important greenhouse gas is sulphur hexafluoride, an almost non-reactive gas widely employed in industrial processes worldwide. Indeed it is estimated that...

  3. Uranium industry annual 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-04-01

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

  4. Uranium industry annual 1996

    International Nuclear Information System (INIS)

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

  5. Uranium industry annual, 1991

    International Nuclear Information System (INIS)

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

  6. Engineering analysis for disposal of depleted uranium tetrafluoride (UF4)

    International Nuclear Information System (INIS)

    This report presents and evaluates options for disposing of depleted uranium in the chemical form of uranium tetrafluoride (UF4). Two depleted uranium inventories are considered. One results from the original U.S. Department of Energy (DOE) inventory of 560,000 metric tons (te) of depleted uranium hexafluoride (UF6); the other inventory is the original DOE inventory augmented by 145,000 te of depleted UF6 from the United States Enrichment Corporation. Preconceptual designs are included for three disposal options: disposal in a vault, disposal in an engineered trench, and disposal in a deep mine cavity. The disposal container is taken to be either a 30-gallon drum or a 55-gallon drum. Descriptions of the facilities associated with the three disposal options are provided. Staffing estimates for the construction and operation of the facilities are also provided. Wastes and emissions from the facilities during construction, operation, and maintenance have been estimated. Parametric studies have also been performed on the basis of 25% and 50% of the original inventory

  7. Study of the aqueous chemical treatment of uranium zirconium fuels

    International Nuclear Information System (INIS)

    A dry process has been studied for separating the uranium from the zirconium-either for recovering the enriched uranium from fuel element production waste, or with a view to treating this waste after irradiation. In this process the alloy is treated with hydrochloric acid at 400 deg. C in a fluidized corundum bed which causes the zirconium to volatilize as tetrachloride and the uranium to form the trichloride. This latter is then converted to the hexafluoride by attack with fluorure. After the laboratory tests, a first pilot plant with a capacity of 1 kg of alloy was tried out at the Fontenay-aux-Roses Nuclear Research Centre; this made it possible to fix the operational conditions for the process. An industrial scale plant was then built with the collaboration of the from Kuhlmann, and operated until a satisfactory process had been developed for treating the waste. This installation treats 3 kg/h of alloy with a yield for the hydrochloric acid of about 50 per cent and with a uranium loss in the zirconium tetrachloride of about 0.1 per cent. An active pilot plant capable of treating of treating a few kilos of irradiated alloy is now being studied. (authors)

  8. Radar reflectivity of bare and vegetation-covered soil

    Science.gov (United States)

    Ulaby, F. T.; Dobson, M. C.; Bradley, G. A.

    1981-01-01

    Radar sensitivity to soil moisture content has been investigated experimentally for bare and vegetation-covered soil using detailed spectral measurements obtained by a truck-mounted radar spectrometer in the 1-8 GHz band and by airborne scatterometer observations at 1.6, 4.75, and 13.3 GHz. It is shown that radar can provide quantitative information on the soil moisture content of both bare and vegetation-covered soil. The observed soil moisture is in the form of the soil matric potential or a related quantity such as the percent of field capacity. The depth of the monitored layer varies from 1 cm for very wet soil to about 15 cm for very dry soil.

  9. Assembling Bare Au Nanoparticles at Positively Charged Templates

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wenjie; Zhang, Honghu; Kuzmenko, Ivan; Mallapragada, Surya; Vaknin, David

    2016-05-26

    In-situ X-ray reflectivity (XRR) and grazing incidence X-ray small-angle scattering (GISAXS) reveal that unfunctionalized (bare) gold nanoparticles (AuNP) spontaneously adsorb to a cationic lipid template formed by a Langmuir monolayer of DPTAP (1,2-dihexadecanoyl-3-trimethylammonium-propane) at vapor/aqueous interfaces. Analysis of the XRR yields the electron density profile across the chargedinterfaces along the surface normal showing the AuNPs assemble with vertical thickness comparable to the particle size. The GISAXS analysis indicates that the adsorbed mono-particle layer exhibits shortrange in-plane correlations. By contrast, single-stranded DNA-functionalized AuNPs, while attracted to the positively charged surface (more efficiently with the addition of salt to the solution), display less in-plane regular packing compared to bare AuNPs.

  10. Dynamic Vision Sensor Camera Based Bare Hand Gesture Recognition

    OpenAIRE

    kashmera ashish khedkkar safaya; Rekha Lathi

    2012-01-01

    This Paper proposes a method to recognize bare hand gestures using dynamic vision sensor (DVS) camera. DVS camera only responds asynchronously to pixels that have temporal changes in intensity which different from conventional camera. This paper attempts to recognize three different hand gestures rock, paper and scissors and using those hand gestures design mouse free interface.   Keywords: Dynamic vision sensor camera, Hand gesture recognition

  11. Dynamic Vision Sensor Camera Based Bare Hand Gesture Recognition

    Directory of Open Access Journals (Sweden)

    kashmera ashish khedkkar safaya

    2012-05-01

    Full Text Available This Paper proposes a method to recognize bare hand gestures using dynamic vision sensor (DVS camera. DVS camera only responds asynchronously to pixels that have temporal changes in intensity which different from conventional camera. This paper attempts to recognize three different hand gestures rock, paper and scissors and using those hand gestures design mouse free interface.   Keywords: Dynamic vision sensor camera, Hand gesture recognition

  12. The Political Animal: Species-Being and Bare Life

    Directory of Open Access Journals (Sweden)

    Laura Hudson

    2008-01-01

    Full Text Available Marxism has been justifiably skeptical of animal rights. Indeed, deep ecology and animal-rights discourse are, in their native habitats, deeply problematic and self-contradictory. But recent theories of “bare life,” when brought into dialogue with Marx’s concept of species-being, offer a perspective from which animal rights discourse and Marxism share a common political horizon.

  13. Photon emissivity of the electrosphere of bare strange stars

    OpenAIRE

    Harko, T.; Cheng, KS

    2005-01-01

    We consider the spectrum, emissivity, and flux of the electromagnetic radiation emitted by the thin electron layer (the electrosphere) at the surface of a bare strange star. In particular, we carefully consider the effect of the multiple and uncorrelated scattering on the radiation spectrum (the Landau-Pomeranchuk-Migdal effect), together with the effect of the strong electric field at the surface of the star. The presence of the electric field strongly influences the radiation spectrum emitt...

  14. Single ionization of diatomic molecules by bare ion impact

    International Nuclear Information System (INIS)

    The molecular three-Coulomb wave model (M3CW) has been extensively used to study the double-differential ionization cross sections (DDCS) of diatomic molecules by the impact of bare ions at intermediate and high energies. In this model, the distortion of the initial channel by the incoming projectile is also included. The present DDCS results are found to be in good accord both with the experiment of Baran et al 2008 as well as with other theory

  15. The Political Animal: Species-Being and Bare Life

    OpenAIRE

    Laura Hudson

    2008-01-01

    Marxism has been justifiably skeptical of animal rights. Indeed, deep ecology and animal-rights discourse are, in their native habitats, deeply problematic and self-contradictory. But recent theories of “bare life,” when brought into dialogue with Marx’s concept of species-being, offer a perspective from which animal rights discourse and Marxism share a common political horizon.

  16. Uranium market

    International Nuclear Information System (INIS)

    Neuxco's estimates of uranium output from operating US centers plus facilities under construction are tabulated through 1990. Buyer inventories will continue to grow through the end of 1982 and will fall off thereafter. The relative inventory level will remain at two years or above through 1984, and will consistently drop thereafter. This is an indication of the market available for imports and for new US production. 1 table

  17. Depleted uranium

    International Nuclear Information System (INIS)

    Full text: The Director General of the International Atomic Energy Agency (IAEA), Mohamed ElBaradei, issued today the following statement: The IAEA has been involved in United Nations efforts relating to the impact of the use of depleted uranium (DU) ammunition in Kosovo. It has supported the United Nations Environment Programme (UNEP) in the assessment which it is making, at the request of the Secretary-General, of that impact. In this connection, in November 2000, Agency experts participated in a UNEP-led fact-finding mission in Kosovo. DU is only slightly radioactive, being about 40% as radioactive as natural uranium. Chemically and physically, DU behaves in the same way as natural uranium. The chemical toxicity is normally the dominant factor for human health. However, it is necessary to carefully assess the impact of DU in the special circumstances in which it was used, e.g. to determine whether it was inhaled or ingested or whether fragments came into close contact with individuals. It is therefore essential, before an authoritative conclusion can be reached, that a detailed survey of the territory in which DU was used and of the people who came in contact with the depleted uranium in any form be carried out. In the meantime it would be prudent, as recommended by the leader of the November UNEP mission, to adopt precautionary measures. Depending on the results of the survey further measures may be necessary. The Agency, within its statutory responsibilities and on the basis of internationally accepted radiation safety standards, will continue to co-operate with other organizations, in particular WHO and UNEP, with a view to carrying out a comprehensive assessment. Co-operation by and additional information from NATO will be prerequisites. The experience gained from such an assessment could be useful for similar studies that may be carried out elsewhere in the Balkans or in the Gulf. (author)

  18. Thermodynamic analysis of flame processes used in the preparation and processing of uranium fluorides

    International Nuclear Information System (INIS)

    Adiabatic temperatures of burning in the course of UF4, UO2, U3O8 and UO2F2 fluorination, reduction of uranium hexafluoride using H2, NH3 or CCl4, pyrohydrolysis of UF6 by water steam, as well as in H2-O2 or NH3-O2 flame, were calculated using the Chemical workbench program developed by RRC Kurchatov Institute. Dependences of the process temperatures and target product yields on the ratio of reacting components are ascertained. It is shown that flame reactor in principle can be used for fluorinating the substances with burning temperatures of at least 1200-1300 K

  19. Uranium enrichment

    International Nuclear Information System (INIS)

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

  20. Brazilian uranium exploration program

    International Nuclear Information System (INIS)

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

  1. Charge changing cross sections of relativistic uranium

    International Nuclear Information System (INIS)

    We report equilibrium charge state distributions of uranium at energies of 962 MeV/nucleon, 437 MeV/nucleon and 200 MeV/nucleon in low Z and high Z targets and the cross sections for U92+ reversible U91+ and U91+ reversible U90+ at 962 MeV/nucleon and 437 MeV/nucleon. Equilibrium thickness Cu targets produce approx. = 5% bare U92+ at 200 MeV/nucleon and 85% U92+ at 962 MeV/nucleon. 7 references, 5 figures

  2. Uranium industry annual, 1986

    International Nuclear Information System (INIS)

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

  3. An experimental and analytical study of heat transfer characteristic of a UF6-filled vessel

    International Nuclear Information System (INIS)

    Experimental and analytical study was conducted aiming at a better understanding of thermal behavior of uranium hexafluoride in cylinders. The experimental study includes the measurement for thermal conductivity of solid and liquid uranium hexafluoride as well as the thermal test for a bare vessel filled with about 110 kg of uranium hexafluoride. The thermal conductivity of solid and liquid uranium hexafluoride was measured by steady and non-steady methods and was found to be in fairly good agreement with the values estimated by the Webers empirical equation. The thermal test was conducted to observe the phase changes of inner uranium hexafluoride as a function of time and location as well as the apparent heat transfer coefficient between the cylinder material and inner uranium hexafluoride. Based on both the observation of this thermal test and the experimental determination of thermal conductivity, the two-dimensional analysis is carried out to complete liquefraction of uranium hexafluoride in the test cylinder by using a Phoenics code which takes direct account of fluid flow effect

  4. Uranium Industry Annual, 1992

    International Nuclear Information System (INIS)

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

  5. Uranium Industry Annual, 1992

    Energy Technology Data Exchange (ETDEWEB)

    1993-10-28

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

  6. Thermomechanical and isothermal fatigue behavior of bare and coated superalloys

    International Nuclear Information System (INIS)

    Thermomechanical fatigue (TMF) and isothermal fatigue (IF) experiments were performed on bare Mar-M246 as well as bare and coated Mar-M247 nickel based superalloys at strain ranges from 0.335 to 1 percent. The experiments were conducted in air, through a temperature range of 500 to 1,038 C at a constant strain rate of 5.0 x 10-5 s-1. Due to the coarse-grained structure of Mar-M246, TMF lives scattered considerably under low strain range conditions. Electron microscopy studies show that significant surface oxidation and gamma prime, γ', depleted zones occur for Mar-M246 under these conditions. In the surface grain, where the change in γ' morphology is most pronounced, γ' rafted along axes ∼±45 deg from the loading axis. The influence of a protective coating on the IF and TMF lives of Mar-M247 was also examined. Results indicate that the coating does not significantly affect the fatigue lives of Mar-M247. The oxidation behavior of bare and coating Mar-M247 was investigated via X-ray microprobe and Auger Spectroscopy. Through these analyses, it is evident that the coating was completely degraded when exposed to the test environment for a long time. In both Mar-M246 and Mar-M247, in-phase thermomechanical fatigue (TMF IP) loading resulted in intergranular cracking. TMF IP loading promoted multiple cracks at the coating/substrate interface of coating Mar-M247. Finally, Eshelby techniques were used to calculate stress distributions in the vicinity of a surface oxide and second-phase particle at the coating/substrate interface

  7. Wave energy resource in the Estaca de Bares area (Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Iglesias, G.; Carballo, R. [Univ. of Santiago de Compostela, EPS, Hydraulic Eng., Campus Univ. s/n, 27002 Lugo (Spain)

    2010-07-15

    The area around Cape Estaca de Bares (the northernmost point of Iberia) presents a great potential for wave energy exploitation owing to its prominent position, with average deepwater wave power values exceeding 40 kW/m. The newly available SIMAR-44 dataset, composed of hindcast data spanning 44 years (1958-2001), is used alongside wave buoy data and numerical modelling to assess this substantial energy resource in detail. Most of the energy is provided by waves from the IV quadrant, generated by the prevailing westerlies blowing over the long Atlantic fetch. Combined scatter and energy diagrams are used to characterise the wave energy available in an average year in terms of the sea states involved. The lion's share is shown to correspond to significant wave heights between 2 and 5 m and energy periods between 11 and 14 s. The nearshore energy patterns are then examined using a coastal wave model (SWAN) with reference to four situations: average wave energy, growing wave energy (at the approach of a storm), extreme wave energy (at the peak of the storm) and decaying wave energy (as the storm recedes). The irregular bathymetry is found to produce local concentrations of wave energy in the nearshore between Cape Prior and Cape Ortegal and in front of Cape Estaca de Bares, with similar patterns (but varying wave power) in the four cases. These nearshore areas of enhanced wave energy are of the highest interest as prospective sites for a wave energy operation. The largest of them is directly in the lee of a large underwater mount west of Cape Ortegal. In sum, the Estaca de Bares area emerges as one of the most promising for wave energy exploitation in Europe. (author)

  8. Swift monitoring of the "bare" AGN Ark120

    Science.gov (United States)

    Gliozzi, Mario

    2016-01-01

    We present the first results from our monitoring campaign of the prototypical bare AGN Ark 120 observed with the Swift UVOT and XRT. A simultaneous study of UV, optical, and X-ray variability in AGN is one of the most effective tools to shed light on their central engine. Ark 120 appears to be highly variable at all wavelengths and over all the timescales probed during the Swift campaign, with a higher degree of variability in the higher energy bands. The temporal variations are accompanied by spectral changes, which may provide crucial information on the origin of variability and the interplay between disk and corona in AGN.

  9. Preparation of plutonium hexafluoride. Recovery of plutonium from waste dross (1962)

    International Nuclear Information System (INIS)

    The object of this work is to study the influence of various physical factors on the rate of fluorination of solid plutonium tetrafluoride by fluorine. In a horizontal oven with a circulation for pure fluorine at atmospheric pressure and 520 deg. C, at a fluorine rate of 9 litres/hour, it is possible to transform 3 g of tetrafluoride to hexafluoride with about 100 per cent transformation and a recovery yield of over 90 per cent, in 4 to 5 hours. The fluorination rate is a function of the temperature, of the fluorine flow-rate, of the crucible surface, of the depth of the tetrafluoride layer and of the reaction time. It does not depend on the diffusion of the fluorine into the solid but is determined by the reaction at the gas-solid interface and obeys the kinetic law (1 - TT)1/3 = kt + 1. The existence of intermediate fluorides, in particular Pu4 F17, is confirmed by a break in the Arrhenius plot at about 370 deg. C, by differences in the fluorination rates inside the tetrafluoride layer, and by reversible colour changes. The transformation to hexafluoride occurs with a purification with respect of the foreign elements present in the initial plutonium. Recovery of plutonium from waste dross: The study is based on the transformation of occluded plutonium particles to gaseous hexafluoride which is then decomposed thermally to the tetrafluoride which can be reintroduced directly in the production circuit. Under the conditions considered this process is not applicable industrially. After milling, it is possible to separate the dross into enriched (75 per cent Pu in 2.6 per cent by weight of dross) and depleted portions. By prolonged fluorination (16 hours) of the various fractions it is possible to recover about 80 per cent of the plutonium. A treatment plant using fluidization, as described at the end of this study, should make it possible to substantially improve the yield. (author)

  10. Efficient vitreolysis by combining plasmin and sulfur hexafluoride injection in a preclinical study in rabbit eyes

    OpenAIRE

    Wu, Wei-Chi; Liu, Chi-Hsien; Chen, Chih-Chun; Wang, Nan-Kai; Chen, Kwan-Jen; Chen, Tun-Lu; Hwang, Yih-Shiou; Li, Lien-Min; Lai, Chi-Chun

    2012-01-01

    Purpose To investigate the efficacy of plasmin and sulfur hexafluoride (SF6) on the vitreoretinal junction, as well as the long-term safety in the eye and effect on the recipient’s general health after application in the eye. Methods The study design included four groups of rabbits with three animals in each group. Group 1 received an intravitreal injection (IVI) of plasmin and SF6 in the right eye; group 2 received an IVI of plasmin in the right eye; group 3 received an IVI of SF6 in the rig...

  11. GAS CHROMATOGRAPHIC-MASS SPECTROMETRIC ANALYSIS OF HIGH PURITY SULFUR HEXAFLUORIDE ENRICHED WITH 32S ISOTOPE

    OpenAIRE

    Krylov, V. A.; Sozin, A. Iu.; Chernova, O. Iu.

    2016-01-01

    The method of gas chromatography-mass spectrometry was used for the first time to investigate the impurity composition of high-purity sulfur hexafluoride enriched with 32S isotope. For the separation of impurities an adsorption capillary column GS-GasPro of 60 m ´ 0.32 mm with a modified silica gel and a column of 25 m × 0.26 mm, df = 0.25 microns with  a poly trimethylsilyl propyne (PTMSP) were used. It was shown that GS-GasPro column allowed separating the impurity substances with low molec...

  12. Uranium enrichment

    International Nuclear Information System (INIS)

    This chapter discusses the development of uranium enrichment processes. In the introduction there is a brief history of uranium enrichment, followed by a summary of the criteria used for the assessment of an isotope separation process, e.g. the separation factor, separative power, and the power consumption of a separating element. This is followed by a discussion of the two main processes used, i.e. gaseous diffusion and centrifugation. The reason for the change from diffusion to centrifugation in the UK, mainly on power costs, is discussed. The development potential of centrifuges is also assessed. Other processes which have been developed up to pilot stage are described, e.g. the Becker jet nozzle and the South African process. This is followed by a description of some plasma-based methods. The next topic is concerned with chemical exchange methods and an attempt is made to assess their potential in the enrichment scene from published information. This chapter concludes with a discussion of the advanced laser isotope-separation methods. The two approaches, i.e. the atomic and the molecular routes are discussed again using published information. This information is insufficient to give a complete assessment of the methods, especially the molecular route, but is enough to give indications of their potential

  13. Uranium processing and properties

    CERN Document Server

    2013-01-01

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

  14. Irradiated uranium reprocessing

    International Nuclear Information System (INIS)

    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

  15. Issues in uranium availability

    International Nuclear Information System (INIS)

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

  16. Bare Metal Stenting for Endovascular Exclusion of Aortic Arch Thrombi

    Energy Technology Data Exchange (ETDEWEB)

    Mahnken, Andreas H., E-mail: mahnken@med.uni-marburg.de [University Hospital Giessen and Marburg, Philipps University of Marburg, Department of Diagnostic Radiology (Germany); Hoffman, Andras; Autschbach, Ruediger; Damberg, Anneke L. M., E-mail: anneke.damberg@rwth-aachen.de [University Hospital RWTH Aachen, Department of Thoracic, Cardiac and Vascular Surgery (Germany)

    2013-08-01

    BackgroundAortic thrombi in the ascending aorta or aortic arch are rare but are associated with a relevant risk of major stroke or distal embolization. Although stent grafting is commonly used as a treatment option in the descending aorta, only a few case reports discuss stenting of the aortic arch for the treatment of a thrombus. The use of bare metal stents in this setting has not yet been described.MethodsWe report two cases of ascending and aortic arch thrombus that were treated by covering the thrombus with an uncovered stent. Both procedures were performed under local anesthesia via a femoral approach. A femoral cutdown was used in one case, and a total percutaneous insertion was possible in the second case.ResultsBoth procedures were successfully performed without any periprocedural complications. Postoperative recovery was uneventful. In both cases, no late complications or recurrent embolization occurred at midterm follow-up, and control CT angiography at 1 respectively 10 months revealed no stent migration, freely perfused supra-aortic branches, and no thrombus recurrence.ConclusionTreating symptomatic thrombi in the ascending aorta or aortic arch with a bare metal stent is feasible. This technique could constitute a minimally invasive alternative to a surgical intervention or complex endovascular therapy with fenestrated or branched stent grafts.

  17. Uranium industry annual 1985

    International Nuclear Information System (INIS)

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

  18. Study contribution to the new international philosophy of the radiological safety system on chemical processing of the natural uranium

    International Nuclear Information System (INIS)

    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)

  19. The regulation of uranium refineries and conversion facilities in Canada

    International Nuclear Information System (INIS)

    The nuclear regulatory process as it applies to uranium refineries and conversion facilities in Canada is reviewed. In the early 1980s, Eldorado Resources Limited proposed to construct and operate new facilities for refining yellowcake and for the production of uranium hexafluoride (UF6). These projects were subject to regulation by the Atomic Energy Control Board (AECB). A description of the AECB's comprehensive licensing process covering all stages of siting, construction, operation and eventual decommissioning of nuclear facilities is traced as it was applied to the Eldorado projects. The AECB's concern with occupational health and safety, with public health and safety and with the protection of the environment in so far as it affects public health and safety is emphasized. Some regulatory difficulties encountered during the project's development which led to opening up the licensing process to public input and closer coordination of regulatory activities with other provincial and federal regulatory agencies are described. The Board's regulatory operational compliance program for uranium refineries and conversion facilities is summarized

  20. Implementation of conduct of operations at Paducah uranium hexafluoride (UF{sub 6}) sampling and transfer facility

    Energy Technology Data Exchange (ETDEWEB)

    Penrod, S.R. [Martin Marietta Energy Systems, Inc., KY (United States)

    1991-12-31

    This paper describes the initial planning and actual field activities associated with the implementation of {open_quotes}Conduct of Operations{close_quotes}. Conduct of Operations is an operating philosophy that was developed through the Institute of Nuclear Power Operations (INPO). Conduct of Operations covers many operating practices and is intended to provide formality and discipline to all aspects of plant operation. The implementation of these operating principles at the UF{sub 6} Sampling and Transfer Facility resulted in significant improvements in facility operations.

  1. Implementation of conduct of operations at Paducah uranium hexafluoride (UF{sub 6}) sampling and transfer facility

    Energy Technology Data Exchange (ETDEWEB)

    Penrod, S.R. [Martin Marietta Energy Systems, Inc., KY (United States)

    1991-12-31

    This paper describes the initial planning and actual field activities associated with the implementation of {open_quotes}Conduct of Operations{close_quotes}, Conduct of Operations is an operating philosophy that was developed through the Institute of Nuclear Power Operations (INPO). Conduct of Operations covers many operating practices and is intended to provide formality and discipline to all aspects of plant operation. The implementation of these operating principles at the UF{sub 6} Sampling and Transfer Facility resulted in significant improvements in facility operations.

  2. Diagnosis and suggestions for the knowledge management applied to a nuclear installation: the uranium hexafluoride production unit

    International Nuclear Information System (INIS)

    It has been more than 25 years since Brazilian Navy started applying resources and staff in a nuclear power program in which the main objective is the necessary technology for project and construction of a nuclear power reactor and nuclear fuel production for naval propulsion. A long period project tends to be susceptible to loss of essential parcels of knowledge. The objective of the present research is to identify actions and initiatives that may improve learning and dissemination of knowledge in an organization that develops complexes projects during a long period of time. The revision of the literature about Knowledge Management allowed the researcher to select a reference that indicates how people involved in a project gets the necessary information and knowledge for developing their activities and uses them to add value and to learn how to contribute for the organization, in order to prevent nature difficulties. The adopted methodology was a case study on the implantation of the Unidade de Hexafluoreto de Uranio, which is being developed by the Centro Tecnologico da Marinha in Sao Paulo. With the application of structured and opened interviews, it was possible to identify some factors related with the attainment and dissemination of knowledge that can be developed. The result of this work was a proposal of action and initiatives that will improve the attainment of the knowledge, its structure and maintenance by the organization and the contribution by the people, of the knowledge acquired. (author)

  3. Safety analysis report on the ''Paducah Tiger'' protective overpack for 10-ton cylinders of uranium hexafluoride. Supplement 1

    International Nuclear Information System (INIS)

    This supplement details design changes made to the ''Paducah Tiger'' since the issue date of the SAR, June 16, 1976. A 3/8-inch thick, 304L stainless steel plate has been added on the valve end of existing and future overpacks to provide increased puncture resistance and the overpack cavity has been modified to preclude incorrect loading of the type 48X cylinder. Temperature profiles of the ''Paducah Tiger'' during the 30-minute fire test are included

  4. Update and insulation testing for uranium hexafluoride transport overpacks. United States Department of Transportation specification 21PF-1

    International Nuclear Information System (INIS)

    The slightly enriched product UF6 shipped from the enriching plants for the world's nuclear power plants must be protected in order to conform to domestic and international transport regulations. The principal overpack currently in use is the US Department of Transportation (DOT) Specification 21PF-1 which protects Model 30 UF6 cylinders (Title 49, Code of Federal Regulations, Part 178.121, Specification 21PF-1; Fire and Shock Resistant, Phenolic-Foam Insulated, Metal Overpack. Specification 21PF-1 (Horizontal Loading Overpack)). Operational problems have developed from both design and lack of maintenance, resulting in the entry of water into the insulation zone. In order to minimize this water entry, design modifications are necessary to the 21PF-1 overpacks. Proposed modifications for existing overpacks are to be made only after any water absorbed within the phenolic foam insulation is reduced to an acceptable level. New 21PF-1 overpacks will be fabricated under an enhanced design. In both cases, proposed quality assurance/control requirements in the fabrication, modification, use and maintenance of the overpacks are applicable to fabricators, modifiers, owners and users. Design changes are reviewed in Part I. The phenolic foam is the thermal barrier of the protective overpacks, which maintains the UF6 below its triple point in the event of exposure to elevated temperatures. Evaluation of the thermal qualities of the overpack required extensive analytical modeling correlated with experimental measurement. An experimental programme was devised to measure the thermal conductivity and heat capacity of the phenolic foam from room temperature to approximately 1475 deg. F (1073K). The test programme, which consisted of the guarded hot plate method for thermal conductivity and drop calorimetry for heat capacity determination, is reviewed in Part II. (author)

  5. Production of uranium hexafluoride by the catalysed fluorox process: pilot plant and supporting bench-scale studies

    International Nuclear Information System (INIS)

    The feasibility of producing UF6 by the catalysed reaction of UF4 with oxygen (the Fluorox process) was investigated in a 150 mm diameter fluidised bed reactor and in supporting bench-scale experiments. The rate of the Fluorox reaction in batch experiments was increased by an order of magnitude with 1 to 5 per cent catalyst (containing 3 to 4 per cent platinum on alumina). The maximum UF6 production rate at 650 deg. C was 0.9 kg h-1. However, the platinum catalyst was completely poisoned after production of only 1 and 20 kg UF6 per kg of catalyst when using respectively French and British UF4. Regeneration of the catalyst was demonstrated to be technically feasible by washing with water or ammonium oxalate solution or treating with hydrogen and hydrogen fluoride at 350-650 deg. C. However, since the very fast rate of poisoning would necessitate higher catalyst concentrations and/or frequent regeneration, the catalysed Fluorox process in unlikely to be economically competitive with the direct fluorination of UF4

  6. Mathematical model of a record type device for valued components recovery from end process gases of uranium hexafluoride production

    OpenAIRE

    Bereza, V. N.; Dyadik, Valery Feodosievich; Baydali, Sergey Anatolievich

    2007-01-01

    Mathematical model of the device for valued components recovery from end gases of sublimate production including hydrodynamics, thermodynamics and kinetics of interaction process of solid and gaseous phases realized in the package MATLAB has been presented. Static and dynamic characteristics of the device as a control object necessary for control algorithm synthesis are obtained and analyzed

  7. Methods to investigate the interaction of 16 μm laser radiation with uranium hexafluoride in a supersonic expansion

    Science.gov (United States)

    Human, Hendrik G. C.

    1997-01-01

    Selective dissociation of UF6 using three wavelength IR irradiation did not yield the desired results initially. Various spectroscopic methods such as UV and IR absorption of UF6, fluorescence of UF6 and Time-of-Flight Mass Spectrometry of the products of irradiation, were implemented to investigate the nature of the interaction. These techniques identified the source of the problem as the presence of condensates in the flow-cooled gas, and were used to select conditions to minimise this effect.

  8. Depleted Uranium Management

    International Nuclear Information System (INIS)

    The paper considers radiological and toxic impact of the depleted uranium on the human health. Radiological influence of depleted uranium is less for 60 % than natural uranium due to the decreasing of short-lived isotopes uranium-234 and uranium-235 after enrichment. The formation of radioactive aerosols and their impact on the human are mentioned. Use of the depleted uranium weapons has also a chemical effect on intake due to possible carcinogenic influence on kidney. Uranium-236 in the substance of the depleted uranium is determined. The fact of beta-radiation formation in the uranium-238 decay is regarded. This effect practically is the same for both depleted and natural uranium. Importance of toxicity of depleted uranium, as the heavier chemical substance, has a considerable contribution to the population health. The paper analyzes risks regarding the use of the depleted uranium weapons. There is international opposition against using weapons with depleted uranium. Resolution on effects of the use of armaments and ammunitions containing depleted uranium was five times supported by the United Nations (USA, United Kingdom, France and Israel did not support). The decision for banning of depleted uranium weapons was supported by the European Parliament

  9. URANIUM DECONTAMINATION

    Science.gov (United States)

    Buckingham, J.S.; Carroll, J.L.

    1959-12-22

    A process is described for reducing the extractability of ruthenium, zirconium, and niobium values into hexone contained in an aqueous nitric acid uranium-containing solution. The solution is made acid-deficient, heated to between 55 and 70 deg C, and at that temperature a water-soluble inorganic thiosulfate is added. By this, a precipitate is formed which carries the bulk of the ruthenium, and the remainder of the ruthenium as well as the zirconium and niobium are converted to a hexone-nonextractable form. The rutheniumcontaining precipitate can either be removed from the solu tion or it can be dissolved as a hexone-non-extractable compound by the addition of sodium dichromate prior to hexone extraction.

  10. Natural uranium

    International Nuclear Information System (INIS)

    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

  11. A study of in-line plutonium isotopic analysis for gaseous plutonium hexafluoride

    International Nuclear Information System (INIS)

    In-line plutonium isotopic analysis of gaseous plutonium hexafluoride (PuF6) is very important for process control and special nuclear material accountability in any plutonium-isotope-separation process that requires a gaseous phase. Although much effort had been devoted to analyze arbitrary plutonium samples, no isotopic analysis had been done on gaseous PuF6 samples. We have initiated a study on the use of a high-resolution, gamma-ray spectroscopy technique to analyze gaseous plutonium hexafluoride. For the first time, PuF6 gas samples with pressures varying from 0.15 to 31 torr, which were directly fed into a gas cell from a process flow loop, were measured. The isotopic results of these measurements agree very well with those of mass spectrometry measurements of solid PuF4. The precision of a 10-min measurement of a 10-torr reactor-grade PuF6 is 1.5% for 238Pu, 0.22% for 239Pu, 0.87% for 240Pu, and 17.5% for 241Pu

  12. Nuclear material control and accounting system evaluation in uranium conversion operations

    International Nuclear Information System (INIS)

    The Nuclear Material Control and Accounting Systems in uranium conversion operations are described. The conversion plant, uses ammonium diuranate (ADU), as starting material for the production of uranium hexafluoride. A combination of accountability and verification measurement is used to verify physical inventory quantities. Two types of inspection are used to minimize the measurements uncertainty of the Material Unaccounted For (MUF) : Attribute inspection and Variation inspection. The mass balance equation is the base of an evaluation of a Material Balance Area (MBA). Statistical inference is employed to facilitate rapid inventory taking and enhance material control of Safeguards. The calculation of one sampling plan for a MBA and the methodology of inspection evaluation are also described. We have two kinds of errors : no detection and false delation. (author)

  13. Morphology Characterization of Uranium Particles From Laser Ablated Uranium Materials

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    In the study, metallic uranium and uranium dioxide material were ablated by laser beam in order to simulate the process of forming the uranium particles in pyrochemical process. The morphology characteristic of uranium particles and the surface of

  14. Corrosion of bare and galvanized steel in gypsum

    Directory of Open Access Journals (Sweden)

    Gómez, Mercedes

    1988-12-01

    Full Text Available Gypsum is a relatively low-cost building material much abounding in our country. When it is put in contact with steel, it may produce high corrosion rates due to its pH value (close to 7. This work reports the results obtained in studying the corrosion rates of bare and galvanized steel in contact with gypsum and plaster, as well as the influence curing thermal treatment applied to gypsum, enviromental relative humidity and addition of compounds with different natures and purposes may have in such process. In-situ observations, as well as the measurement of the Polarization Resistance and the weight loss have been used as measurement technics. From the results obtained it has been possible to deduce that galvanized steel has better behaviour in dry enviroments than bare steel in the same conditions and moist atmosphere induces proportionally more corrosion in galvanized steel than in bare one. Additions to gypsum do not modified these conclusions, though it may be pointed out that addition of nitrites or lime improves the behaviour of bare steel, while galvanized behaviour is not modified. The addition of lime is not recommended because phenomena of dilated along time expansion may take place.

    El yeso es un material de construcción de relativo bajo coste y que, además, es muy abundante en nuestro país. Debido a su pH cercano a la neutralidad, cuando entra en contacto con el acero, este puede corroerse a elevadas velocidades. En esta comunicación se presentan los resultados de un estudio sobre la velocidad de corrosión del acero desnudo y galvanizado en contacto con yeso y escayola y la influencia que tienen: el tratamiento térmico del curado del yeso, la humedad relativa ambiental y la adición de aditivos de diversa naturaleza y finalidad. Como técnicas de medida se han utilizado la medida de la Resistencia de Polarización y de la pérdida de peso, así como observaciones visuales. De los resultados se puede deducir que en

  15. Regular step distribution of the bare Si(553) surface

    Science.gov (United States)

    Kopciuszyński, M.; Dyniec, P.; Zdyb, R.; Jałochowski, M.

    2015-06-01

    Vicinal Si(111) surfaces are known to undergo faceting when the temperature is lowered below the (1 ×1 ) to (7 ×7 ) phase transition temperature. Depending on the cutoff angle value and direction with respect to the crystallographic axis, various facets, together with low Miller index terraces, are formed. Here, we report the formation of regularly distributed steps over macroscopic sample regions of the bare Si(553) surface. The surface morphology is studied with scanning tunneling microscopy and reflection high energy electron diffraction techniques. The (111) terraces of 2.88 nm in width, which are separated by double atomic height steps, reveal an unusual reconstruction. However, the electronic structure determined with angle resolved photoemission spectroscopy shows bands very similar to those observed for the Si (111 )-(7 ×7 ) surface.

  16. Interaction of Hg Atom with Bare Si(111) Surface

    Institute of Scientific and Technical Information of China (English)

    LIU Yong-Jun; LIU Ying

    2006-01-01

    To evaluate the interaction between Hg atom and bare Si(111) surface, three types of silicon cluster models of Si4H7, Si7H10 and Si16H20 together with their Hg complexes were studied by using hybrid (U)B3LYP density functional theory method. Optimized geometries and energies for Hg atom on different adsorption sites indicate that: 1) the binding energies at different adsorption sites are small (ranging from ~3 to 8 kJ/mol dependent on the adsorption sites), suggesting a weak interaction between Hg atom and silicon surface; 2) the most favorable adsorption site is the on top (T) site. By analyzing their natural bonding orbitals, the possible reason of this difference is suggested.

  17. Voltammetry of nitrobenzene at bare and DODAC coated Pt

    International Nuclear Information System (INIS)

    The reductive electrochemistry of nitrobenzene at one concentration was examined 1:1 water-propanol mixture at bare and DODAC covered platinum semi-micro electrodes using cyclic voltammetry. Generally it is believed [1-9] that couple of reduction and oxidation peak is associated with four electron transfer process which leads to the formation of phenylhydroxylamine in neutral and alkaline solutions. During electroreduction of nitrobenzene at a certain concentration, anodic shift is observed (108 mV) on DODAC covered platinum electrode. It reveals that in the presence of cationic micelles [10-18] partition of nitrobenzene occurs where nitrobenzene is more concentrated in micellar phase than in bulk. Cathodic and anodic peak currents show almost linear trend with increasing potential sweep rate. Similar trend is observed for cathodic and anodic peak potentials, respectively. (author)

  18. Uranium management activities

    International Nuclear Information System (INIS)

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

  19. Diurnal emissivity dynamics in bare versus biocrusted sand dunes.

    Science.gov (United States)

    Rozenstein, Offer; Agam, Nurit; Serio, Carmine; Masiello, Guido; Venafra, Sara; Achal, Stephen; Puckrin, Eldon; Karnieli, Arnon

    2015-02-15

    Land surface emissivity (LSE) in the thermal infrared depends mainly on the ground cover and on changes in soil moisture. The LSE is a critical variable that affects the prediction accuracy of geophysical models requiring land surface temperature as an input, highlighting the need for an accurate derivation of LSE. The primary aim of this study was to test the hypothesis that diurnal changes in emissivity, as detected from space, are larger for areas mostly covered by biocrusts (composed mainly of cyanobacteria) than for bare sand areas. The LSE dynamics were monitored from geostationary orbit by the Spinning Enhanced Visible and Infrared Imager (SEVIRI) over a sand dune field in a coastal desert region extending across both sides of the Israel-Egypt political borderline. Different land-use practices by the two countries have resulted in exposed, active sand dunes on the Egyptian side (Sinai), and dunes stabilized by biocrusts on the Israeli side (Negev). Since biocrusts adsorb more moisture from the atmosphere than bare sand does, and LSE is affected by the soil moisture, diurnal fluctuations in LSE were larger for the crusted dunes in the 8.7 μm channel. This phenomenon is attributed to water vapor adsorption by the sand/biocrust particles. The results indicate that LSE is sensitive to minor changes in soil water content caused by water vapor adsorption and can, therefore, serve as a tool for quantifying this effect, which has a large spatial impact. As biocrusts cover vast regions in deserts worldwide, this discovery has repercussions for LSE estimations in deserts around the globe, and these LSE variations can potentially have considerable effects on geophysical models from local to regional scales. PMID:25437760

  20. Uranium Provinces in China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Three uranium provinces are recognized in China, the Southeast China uranium province, the Northeast China-lnner Mongolia uranium province and the Northwest China (Xinjiang) uranium province. The latter two promise good potential for uranium resources and are major exploration target areas in recent years. There are two major types of uranium deposits: the Phanerozoic hydrothermal type (vein type) and the Meso-Cenozoic sandstone type in different proportions in the three uranium provinces. The most important reason or prerequisite for the formation of these uranium provinces is that Precambrian uranium-enriched old basement or its broken parts (median massifs) exists or once existed in these regions, and underwent strong tectonomagmatic activation during Phanerozoic time. Uranium was mobilized from the old basement and migrated upwards to the upper structural level together with the acidic magma originating from anatexis and the primary fluids, which were then mixed with meteoric water and resulted in the formation of Phanerozoic hydrothermal uranium deposits under extensional tectonic environments. Erosion of uraniferous rocks and pre-existing uranium deposits during the Meso-Cenozoic brought about the removal of uranium into young sedimentary basins. When those basins were uplifted and slightly deformed by later tectonic activity, roll-type uranium deposits were formed as a result of redox in permeable sandstone strata.

  1. Uranium industry annual 1998

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-04-22

    The Uranium Industry Annual 1998 (UIA 1998) provides current statistical data on the US uranium industry`s activities relating to uranium raw materials and uranium marketing. It contains data for the period 1989 through 2008 as collected on the Form EIA-858, ``Uranium Industry Annual Survey.`` Data provides a comprehensive statistical characterization of the industry`s activities for the survey year and also include some information about industry`s plans and commitments for the near-term future. Data on uranium raw materials activities for 1989 through 1998, including exploration activities and expenditures, EIA-estimated reserves, mine production of uranium, production of uranium concentrate, and industry employment, are presented in Chapter 1. Data on uranium marketing activities for 1994 through 2008, including purchases of uranium and enrichment services, enrichment feed deliveries, uranium fuel assemblies, filled and unfilled market requirements, and uranium inventories, are shown in Chapter 2. The methodology used in the 1998 survey, including data edit and analysis, is described in Appendix A. The methodologies for estimation of resources and reserves are described in Appendix B. A list of respondents to the ``Uranium Industry Annual Survey`` is provided in Appendix C. The Form EIA-858 ``Uranium Industry Annual Survey`` is shown in Appendix D. For the readers convenience, metric versions of selected tables from Chapters 1 and 2 are presented in Appendix E along with the standard conversion factors used. A glossary of technical terms is at the end of the report. 24 figs., 56 tabs.

  2. Uranium industry annual 1998

    International Nuclear Information System (INIS)

    The Uranium Industry Annual 1998 (UIA 1998) provides current statistical data on the US uranium industry's activities relating to uranium raw materials and uranium marketing. It contains data for the period 1989 through 2008 as collected on the Form EIA-858, ''Uranium Industry Annual Survey.'' Data provides a comprehensive statistical characterization of the industry's activities for the survey year and also include some information about industry's plans and commitments for the near-term future. Data on uranium raw materials activities for 1989 through 1998, including exploration activities and expenditures, EIA-estimated reserves, mine production of uranium, production of uranium concentrate, and industry employment, are presented in Chapter 1. Data on uranium marketing activities for 1994 through 2008, including purchases of uranium and enrichment services, enrichment feed deliveries, uranium fuel assemblies, filled and unfilled market requirements, and uranium inventories, are shown in Chapter 2. The methodology used in the 1998 survey, including data edit and analysis, is described in Appendix A. The methodologies for estimation of resources and reserves are described in Appendix B. A list of respondents to the ''Uranium Industry Annual Survey'' is provided in Appendix C. The Form EIA-858 ''Uranium Industry Annual Survey'' is shown in Appendix D. For the readers convenience, metric versions of selected tables from Chapters 1 and 2 are presented in Appendix E along with the standard conversion factors used. A glossary of technical terms is at the end of the report. 24 figs., 56 tabs

  3. Uranium industry annual 1994

    International Nuclear Information System (INIS)

    The Uranium Industry Annual 1994 (UIA 1994) provides current statistical data on the US uranium industry's activities relating to uranium raw materials and uranium marketing during that survey year. The UIA 1994 is prepared for use by the Congress, Federal and State agencies, the uranium and nuclear electric utility industries, and the public. It contains data for the 10-year period 1985 through 1994 as collected on the Form EIA-858, ''Uranium Industry Annual Survey.'' Data collected on the ''Uranium Industry Annual Survey'' (UIAS) provide a comprehensive statistical characterization of the industry's activities for the survey year and also include some information about industry's plans and commitments for the near-term future. Where aggregate data are presented in the UIA 1994, care has been taken to protect the confidentiality of company-specific information while still conveying accurate and complete statistical data. A feature article, ''Comparison of Uranium Mill Tailings Reclamation in the United States and Canada,'' is included in the UIA 1994. Data on uranium raw materials activities including exploration activities and expenditures, EIA-estimated resources and reserves, mine production of uranium, production of uranium concentrate, and industry employment are presented in Chapter 1. Data on uranium marketing activities, including purchases of uranium and enrichment services, and uranium inventories, enrichment feed deliveries (actual and projected), and unfilled market requirements are shown in Chapter 2

  4. Uranium: one utility's outlook

    International Nuclear Information System (INIS)

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

  5. Uranium: a basic evaluation

    International Nuclear Information System (INIS)

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

  6. Enriching recycled uranium

    International Nuclear Information System (INIS)

    The paper reviews the progress of the use of recycled uranium during the period 1985-8. This article was originally presented as a paper at the 1988 Uranium Institute symposium (which was held in London). A description is given of the differences between natural and recycled uranium, and the presence of U236 in recycled uranium. The concept of equivalent reactivity is described, as well as the cost benefit of using recycled uranium. A summary of Urenco tests and trials with reprocessed uranium is given. Enrichment, UF6 conversion and fuel fabrication are also discussed. (U.K.)

  7. Uranium health physics

    International Nuclear Information System (INIS)

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

  8. Uranium: myths and realities the depleted uranium

    International Nuclear Information System (INIS)

    Uranium is an element whose name causes worry. The uranium properties are very unknown for people. However the element plays an important roll in the Earth as responsible of numerous natural phenomena, which are vital for life evolution. An example of the low knowledge about uranium has been the Balkan syndrome. A relation between cancers and the use of depleted uranium in ammunition in the Balkan War has been pretended to be established. From the beginning, this hypothesis could have been discarded as it has been confirmed and stated in recent reports of UNEP Commissions who have studied this matter. (Author)

  9. Uranium production

    International Nuclear Information System (INIS)

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

  10. ORSPHERE: CRITICAL, BARE, HEU(93.2)-METAL SPHERE

    Energy Technology Data Exchange (ETDEWEB)

    Margaret A. Marshall

    2013-09-01

    In the early 1970’s Dr. John T. Mihalczo (team leader), J.J. Lynn, and J.R. Taylor performed experiments at the Oak Ridge Critical Experiments Facility (ORCEF) with highly enriched uranium (HEU) metal (called Oak Ridge Alloy or ORALLOY) in an attempt to recreate GODIVA I results with greater accuracy than those performed at Los Alamos National Laboratory in the 1950’s (HEU-MET-FAST-001). The purpose of the Oak Ridge ORALLOY Sphere (ORSphere) experiments was to estimate the unreflected and unmoderated critical mass of an idealized sphere of uranium metal corrected to a density, purity, and enrichment such that it could be compared with the GODIVA I experiments. “The very accurate description of this sphere, as assembled, establishes it as an ideal benchmark for calculational methods and cross-section data files.” (Reference 1) While performing the ORSphere experiments care was taken to accurately document component dimensions (±0. 0001 in. for non-spherical parts), masses (±0.01 g), and material data The experiment was also set up to minimize the amount of structural material in the sphere proximity. A three part sphere was initially assembled with an average radius of 3.4665 in. and was then machined down to an average radius of 3.4420 in. (3.4425 in. nominal). These two spherical configurations were evaluated and judged to be acceptable benchmark experiments; however, the two experiments are highly correlated.

  11. Uranium from phosphate ores

    International Nuclear Information System (INIS)

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

  12. Uranium exploration in Australia

    International Nuclear Information System (INIS)

    Australia has more low-cost uranium in deposits than any other country, but finding it is not easy. While the price for uranium has been low, little was found but now exploration is starting to increase.

  13. DEPLETED URANIUM TECHNICAL WORK

    Science.gov (United States)

    The Depleted Uranium Technical Work is designed to convey available information and knowledge about depleted uranium to EPA Remedial Project Managers, On-Scene Coordinators, contractors, and other Agency managers involved with the remediation of sites contaminated with this mater...

  14. Uranium mining in Australia

    International Nuclear Information System (INIS)

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

  15. International trade in uranium

    International Nuclear Information System (INIS)

    The subject is discussed under the following headings: need for security of uranium supply; pressures on international trade; mechanism of international trade; non-proliferation and uranium trade; means of increasing security of supply. (U.K.)

  16. Brazilian uranium deposits

    International Nuclear Information System (INIS)

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

  17. Uranium in Niger

    International Nuclear Information System (INIS)

    This document presents government policy in the enhancement of uranium resources, existing mining companies and their productions, exploitation projects and economical outcome related to the uranium mining and auxiliary activities

  18. EAARL Coastal Topography-Pearl River Delta 2008: Bare Earth

    Science.gov (United States)

    Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Miner, Michael D.; Yates, Xan; Bonisteel, Jamie M.

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived bare earth (BE) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the University of New Orleans (UNO), Pontchartrain Institute for Environmental Sciences (PIES), New Orleans, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the Pearl River Delta in Louisiana and Mississippi, acquired March 9-11, 2008. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the

  19. EAARL Topography - Vicksburg National Military Park 2008: Bare Earth

    Science.gov (United States)

    Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Segura, Martha; Yates, Xan

    2008-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived bare earth (BE) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Gulf Coast Network, Lafayette, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the Vicksburg National Military Park in Mississippi, acquired on March 6, 2008. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed

  20. EAARL Coastal Topography-Chandeleur Islands, Louisiana, 2010: Bare Earth

    Science.gov (United States)

    Nayegandhi, Amar; Bonisteel-Cormier, Jamie M.; Brock, John C.; Sallenger, A.H.; Wright, C. Wayne; Nagle, David B.; Vivekanandan, Saisudha; Yates, Xan; Klipp, Emily S.

    2010-01-01

    These remotely sensed, geographically referenced elevation measurements of lidar-derived bare-earth (BE) and submerged topography datasets were produced collaboratively by the U.S. Geological Survey (USGS), St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the Chandeleur Islands, acquired March 3, 2010. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative airborne lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multispectral color-infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for sub-meter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom

  1. EAARL Coastal Topography - Northeast Barrier Islands 2007: Bare Earth

    Science.gov (United States)

    Nayegandhi, Amar; Brock, John C.; Sallenger, A.H.; Wright, C. Wayne; Yates, Xan; Bonisteel, Jamie M.

    2008-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived bare earth (BE) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the northeast coastal barrier islands in New York and New Jersey, acquired April 29-30 and May 15-16, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom

  2. Radiation damage of uranium

    International Nuclear Information System (INIS)

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

  3. Governing uranium in China

    OpenAIRE

    Patton Schell, Tamara

    2014-01-01

    Nuclear power is playing an increasingly prominent role in China's long-term strategic energy calculus. In response, China is responding by producing more uranium domestically, buying more uranium on the international market, and investing heavily in overseas uranium properties. At the same time, China has been updating its nuclear regulations over the last three decades, resulting in a myriad of regulatory agencies with widely varying responsibilities related to implementing uranium regulati...

  4. Uranium in fossil bones

    International Nuclear Information System (INIS)

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

  5. Bicarbonate leaching of uranium

    International Nuclear Information System (INIS)

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

  6. Uranium mining: Saskatchewan status

    International Nuclear Information System (INIS)

    This paper gives the status of uranium mining by Areva in Saskatchewan. Uranium production now meets 85% of world demand for power generation. 80% of world production of uranium comes from top 5 countries: Kazakhstan, Canada, Australia, Niger and Namibia. Saskatchewan is currently the only Canadian province with active uranium mines and mills and the largest exploration programs. Several mine projects are going through the environmental assessment process. Public opinion is in favour of mining activities in Saskatchewan.

  7. Use of sulfur hexafluoride and perfluorocarbon tracers in plutonium storage containers for leak detection

    International Nuclear Information System (INIS)

    This study involves an investigation of the feasibility of a tracer-based leak detection system for long-term interim plutonium storage. In particular, a protocol has been developed based on the use of inert tracers with varying concentrations in order to open-quotes fingerprintclose quotes or open-quotes tagclose quotes specific containers. A particular combination of tracers at specific ratios could be injected into the free volume of each container, allowing for the detection of leaks as well as determination of the location of leaking containers. Based on plutonium storage considerations, sulfur hexafluoride and four perfluorocarbon tracers were selected and should allow a wide range of viable fingerprinting combinations. A open-quotes high-lowclose quotes protocol which uses two distinct chromatographic peak areas or concentration levels, is recommended. Combinations of air exchange rates, detection durations, and detectability limits are examined in order to predict minimum tracer concentrations required for injection in storage containers

  8. A Sulfur Hexafluoride Sensor Using Quantum Cascade and CO2 Laser-Based Photoacoustic Spectroscopy

    Directory of Open Access Journals (Sweden)

    Helion Vargas

    2010-10-01

    Full Text Available The increase in greenhouse gas emissions is a serious environmental problem and has stimulated the scientific community to pay attention to the need for detection and monitoring of gases released into the atmosphere. In this regard, the development of sensitive and selective gas sensors has been the subject of several research programs. An important greenhouse gas is sulphur hexafluoride, an almost non-reactive gas widely employed in industrial processes worldwide. Indeed it is estimated that it has a radiative forcing of 0.52 W/m2. This work compares two photoacoustic spectrometers, one coupled to a CO2 laser and another one coupled to a Quantum Cascade (QC laser, for the detection of SF6. The laser photoacoustic spectrometers described in this work have been developed for gas detection at small concentrations. Detection limits of 20 ppbv for CO2 laser and 50 ppbv for quantum cascade laser were obtained.

  9. A Sulfur Hexafluoride Sensor Using Quantum Cascade and CO2 Laser-Based Photoacoustic Spectroscopy

    Science.gov (United States)

    Rocha, Mila; Sthel, Marcelo; Lima, Guilherme; da Silva, Marcelo; Schramm, Delson; Miklós, András; Vargas, Helion

    2010-01-01

    The increase in greenhouse gas emissions is a serious environmental problem and has stimulated the scientific community to pay attention to the need for detection and monitoring of gases released into the atmosphere. In this regard, the development of sensitive and selective gas sensors has been the subject of several research programs. An important greenhouse gas is sulphur hexafluoride, an almost non-reactive gas widely employed in industrial processes worldwide. Indeed it is estimated that it has a radiative forcing of 0.52 W/m2. This work compares two photoacoustic spectrometers, one coupled to a CO2 laser and another one coupled to a Quantum Cascade (QC) laser, for the detection of SF6. The laser photoacoustic spectrometers described in this work have been developed for gas detection at small concentrations. Detection limits of 20 ppbv for CO2 laser and 50 ppbv for quantum cascade laser were obtained. PMID:22163412

  10. Multiphoton ionization (MPI) spectroscopy of tungsten hexafluoride: Experimental observation of Molecular spectrum using MPI

    International Nuclear Information System (INIS)

    In general, multiphoton ionization (MPI) spectroscopy of metal complexes shows the dissociation and ionization of the compounds. Well-structured molecular ionization spectrum is not observed yet for metal complexes by use of the multiphoton ionization technique. Tungsten hexafluoride was selected to get a molecular spectrum with MPI technique because it had a very high dissociation energy that might suppress facile photofragmentation. Also, WF6 has high vapor pressure(>1,000 torr at 300 K), which means heating is not required to get enough sample concentration in the molecular beam. The electronic absorption spectrum and the electron impact spectrum of WF6 were previously studied. The assignment of WF6 spectrum obtained by MPI can be compared with those published results. Experimentally, we observed the molecular MPI spectra of WF6 and the clear assignments are not easy with current results as well as previous works.

  11. Uranium resources, 1983

    International Nuclear Information System (INIS)

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

  12. Uranium and thorium

    International Nuclear Information System (INIS)

    Present article is devoted to uranium and thorium content in fluorite. In order to obtain the comprehensive view on uranium and thorium distribution in fluorite 100 fluorite samples of various geologic deposits and ores of Kazakhstan, Uzbekistan, Tajikistan and some geologic deposits of Russia were studied. The uranium and thorium content in fluorite of geologic deposits of various mineralogical and genetic type was defined.

  13. Electron capture by bare ions on water molecules

    Science.gov (United States)

    Rivarola, Roberto; Montenegro, Pablo; Monti, Juan; Fojón, Omar

    2016-05-01

    Single electron capture from water molecules by impact of bare ions is theoretically investigated at intermediate and high collision energies. This reaction is of fundamental importance to determine the deposition of energy in biological matter irradiated with ion beams (hadrontherapy), dominating other ionizing processes of the target at low-intermediate impact velocities and giving principal contributions to the energetic region where electronic stopping power maximizes. The dynamics of the interaction between the aggregates is described within the one active-electron continuum distorted wave-eikonal initial state theory. The orbitals of the target in the ground state are represented using the approximate self-consistent complete neglect of differential orbitals (SC-CNDO) model. The contribution of different molecular orbitals on the partial cross sections to selected n-principal quantum number projectile states is discriminated as well as the collaboration of these n-states on total cross sections. The latter ones are dominated by capture to n=1 states at high enough energies decreasing their contribution as n increases.

  14. Nd-YAG laser welding of bare and galvanised steels

    International Nuclear Information System (INIS)

    Until recently, one of the problems that has held back the introduction of lasers into car body fabrication has been the difficulty of integrating the lasers with robots. Nd-YAG laser beams can be transmitted through fibre optics which, as well as being considerably easier to manipulate than a mirror system, can be mounted on more lightweight accurate robots. Although previously only available at low powers, recent developments in Nd-YAG laser technology mean that lasers of up to 1kW average power will soon be available, coupled to a fibre optic beam delivery system. The increasing usage of zinc coated steels in vehicle bodies has led to welding problems using conventional resistance welding as well as CO2 laser welding. The use of Nd-YAG lasers may be able to overcome these problems. This paper outlines work carried out at The Welding Institute on a prototype Lumonics 800W pulsed Nd-YAG laser to investigate its welding characteristics on bare and zinc coated car body steels

  15. Space Test of Bare-Wire Anode Tethers

    Science.gov (United States)

    Johnson, L.; Fujii, H. A.; Sanmartin, J. R.

    2007-01-01

    An international team, lead by Tokyo Metropolitan University, is developing a mission concept for a suborbital test of orbital-motion-limited (OML) bare-wire anode current collection for application to electrodynamic tether propulsion. The tether is a tape with a 50-mm width, 0.05-mm thickness, and 1-km length. This will be the first space test of the OML theory. In addition, by being an engineering demonstration (of space tethers), the mission will demonstrate electric beam generation for "sounding" determination of the neutral density profile in the ionospheric "E-layer." If selected by the Institute of Space and Astronautical Science/Japanese Aerospace Exploration Agency (JAXA), the mission will launch in early 2009 using an $520 Sounding Rocket. During ascent, and above =100 km in attitude, the 1-km tape tether will be deployed at a rate of 8 m/s. Once deployed, the tape tether will serve as an anode, collecting ionospheric electrons. The electrons will be expelled into space by a hollow cathode device, thereby completing the circuit and allowing current to flow.This paper will describe the objectives of the proposed mission, the technologies to be employed, and the application of the results to future space missions using electrodynamic tethers for propulsion or power generation.

  16. AMQ Protocol Based Performance Analysis of Bare Metal Hypervisors

    Directory of Open Access Journals (Sweden)

    Dr Deepak Arora

    2014-06-01

    Full Text Available Cloud computing is one of the most exciting technology because of its cost-reducing approach, flexibility, and scalability. Hypervisor is the essential part of cloud technology; it is a component of software that provides a virtualized hardware environment to support running multiple operating systems concurrently using one physical server. In this paper we took KVM, XEN, Hyper-V and ESXi as hypervisors. We have compared the performance of Virtual Machines (VMs by RabbitMQ message broker server that uses Advanced Message Queuing Protocol(AMQP for breaking messages. We establish the setup on bare metal hypervisor that is installed directly on the hardware of the system. We took SAN (Shared Storage Network server for maintaining the storage of all VMs. By the evaluation of these hyperviosrs we got a brief idea about their performance on different parameters. These results will be beneficial to small enterprise, social group or any private IT firm which is choosing to build small cloud infrastructure with optimal benefits. Experiment results of checking the performance of VMs for all the hypervisors shows that there is performance variation on different applications and workloads of the hypervisors. None of the hypervisors outperform another at every aspect of our comparison.

  17. Water evaporation from bare soil at Paraiba, Brazil

    International Nuclear Information System (INIS)

    Measurements were accomplished in a 4,0 ha area in Centro de Ciencias Agrarias, UFPB, Areia City, Paraiba State, Brazil (6 deg C 58'S, 35 deg C 41'W and 645 m), aiming to determine water evaporation from bare soil, by energy and water balance approaches. Rain gauge, net radiometer, pyranometer and sensor for measuring the temperature and the relative humidity of the air and the speed of the wind, in two levels above the soil surface, were used to solve the energy balance equations. In the soil, two places were fitted with instruments, each one with two thermal probes, installed horizontally in the depths z1 = 2,0 cm and z2 = 8,0 cm, and a heat flux plate, for the measurement of the heat flux in the soil, the z1 = 5,0 cm. The measured data were stored every 30 minutes in a data logger. For the calculation of the water balance, three tensio-neutronics sites were installed, containing: an access tube for neutrons probe and eight tensiometers. The values of soil evaporation obtained by water balance were lower than obtained by energy balance because of the variability of the water balance terms. (author)

  18. Scattering from bare soils: C-band multipolarization scatterometer measurements

    Science.gov (United States)

    Casarano, Domenico; Buono, G.; Paparella, F.; Posa, Francesco; Sabatelli, Vincenzo

    1998-11-01

    Multi-angle, multi-polarization C-band backscattering measurements were performed over selected bare soil areas. To perform these measurements, an FM-CW radar has been designed and assembled. This device has the capability of resolving independent samples within the antenna footprint area, thus allowing range discrimination and improving the signal statistics. Two areas with different degrees of roughness and dielectric constants were selected and set up. Co-polarized backscattering coefficients were measured for incidence angles between 23 degrees and 60 degrees. To perform a model analysis of the backscattering properties, 'ground truth' data, including surface roughness profiles and soil moisture values (directly related to dielectric constant) were also collected. The 'classical' parameters, used to describe surface roughness, showed a wide spreading. This evidence and the data resulting from ground truth campaigns over many European test sites suggested an alternative description of surface roughness, based on the self-similarity (fractal) properties. The surfaces have therefore been described as fBm (Fractional Brownian Motion) processes, and their backscattering response has been theoretically modeled by a numerical simulation (in 3-D in order to also take into account anisotropy effects) in Kirchhoff approximation. The experimental data have been analyzed with both asymptotic models (IEM) considering a classical statistical description, and with the numerical simulation applied to fBm surfaces.

  19. Fortissimo: A Japanese Space Test Of Bare Wire Anode Tethers

    Science.gov (United States)

    Johnson, Les; Fujii, H. A.; Sanmartin, J. R.

    2008-01-01

    A Japanese led international team is developing a suborbital test of orbital-motion-limited (OML) bare wire anode current collection for application to electrodynamic tether (EDT) propulsion. The tether is a tape with a width of 25 mm, thickness of 0.05 mm, and is 300 m in length. This will be the first space test of OML theory. The mission will launch in the summer of 2009 using an S520 Sounding Rocket. During ascent, and above approx. 100 km in attitude, the tape tether will be deployed at a rate of approx. 8 m/s. Once deployed, the tape tether will serve as an anode, collecting ionospheric electrons. The electrons will be expelled into space by a hollow cathode device, thereby completing the circuit and allowing current to flow. The total amount of current collected will be used to assess the validity of OML theory. This paper will describe the objectives of the proposed mission, the technologies to be employed, and the application of the results to future space missions using EDTs for propulsion or power generation.

  20. Biogeochemistry of uranium minerals

    International Nuclear Information System (INIS)

    Cyclic behaviour in the earth's crust is probably easier to demonstrate for uranium than for most elements. The chenmical basis of that behaviour is described with the roles which organisms can play during their life and as organic residues - after their death. The way in which this behaviour has led to the redistribution of uranium in rocks (to form ore bodies in favourable cases) is considered together with the related topic of biogeochemical prospecting for uranium. Many of the same considerations are relevant to the recovery of uranium by leaching from broken rock and to the way in which the cycling of uranium may affect the environment. (Auth.)

  1. Uranium speciation in plants

    International Nuclear Information System (INIS)

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

  2. The regulation of uranium refineries and conversion facilities in Canada

    International Nuclear Information System (INIS)

    The nuclear regulatory process as it applies to uranium refineries and conversion facilities in Canada is reviewed. In the early 1980s, Eldorado Resources Limited proposed to construct and operate new facilities for refining yellowcake and for the production of uranium hexafluoride (UF6). These projects were subject to regulation by the Atomic Energy Control Board. A description of the Atomic Energy Control Board's comprehensive licensing process covering all stages of siting, construction, operation and eventual decommissioning of nuclear facilities is traced as it was applied to the Eldorado projects. The Atomic Energy Control Board's concern with occupational health and safety, with public health and safety and with protection of the environment so far as it affects public health and safety is emphasized. Some regulatory difficulties encountered during the project's development which led to opening up of the licensing process to public input and closer coordination of regulatory activities with other provincial and federal regulatory agencies are described. The Board's regulatory operational compliance program for U refineries and conversion facilities is summarized. (author)

  3. Bremsstrahlung from relativistic bare heavy ions: Nuclear and electronic contributions in amorphous and crystalline materials

    DEFF Research Database (Denmark)

    Jensen, Tue Vissing; Sørensen, Allan Hvidkjær

    2013-01-01

    A charged particle emits bremsstrahlung while traversing matter. We calculate the radiation cross section for bare heavy ions penetrating amorphous materials and single crystals at highly relativistic energies. The main component originates in scattering of the virtual photons of screened target...... a pronounced directional dependence of the energy loss of bare heavy ions at extreme relativistic energies....

  4. Hydrodynamic behavior of a bare rod bundle. [LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Bartzis, J.G.; Todreas, N.E.

    1977-06-01

    The temperature distribution within the rod bundle of a nuclear reactor is of major importance in nuclear reactor design. However temperature information presupposes knowledge of the hydrodynamic behavior of the coolant which is the most difficult part of the problem due to complexity of the turbulence phenomena. In the present work a 2-equation turbulence model--a strong candidate for analyzing actual three dimensional turbulent flows--has been used to predict fully developed flow of infinite bare rod bundle of various aspect ratios (P/D). The model has been modified to take into account anisotropic effects of eddy viscosity. Secondary flow calculations have been also performed although the model seems to be too rough to predict the secondary flow correctly. Heat transfer calculations have been performed to confirm the importance of anisotropic viscosity in temperature predictions. All numerical calculations for flow and heat have been performed by two computer codes based on the TEACH code. Experimental measurements of the distribution of axial velocity, turbulent axial velocity, turbulent kinetic energy and radial Reynolds stresses were performed in the developing and fully developed regions. A 2-channel Laser Doppler Anemometer working on the Reference mode with forward scattering was used to perform the measurements in a simulated interior subchannel of a triangular rod array with P/D = 1.124. Comparisons between the analytical results and the results of this experiment as well as other experimental data in rod bundle array available in literature are presented. The predictions are in good agreement with the results for the high Reynolds numbers.

  5. 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....

  6. Extremely Nonlinear Optics Using Shaped Pulses Spectrally Broadened in an Argon- or Sulfur Hexafluoride-Filled Hollow-Core Fiber

    Directory of Open Access Journals (Sweden)

    Andreas Hoffmann

    2015-11-01

    Full Text Available In this contribution we present a comparison of the performance of spectrally broadened ultrashort pulses using a hollow-core fiber either filled with argon or sulfur hexafluoride (SF6 for demanding pulse-shaping experiments. The benefits of both gases for pulse-shaping are studied in the highly nonlinear process of high-harmonic generation. In this setup, temporally shaping the driving laser pulse leads to spectrally shaping of the output extreme ultraviolet (XUV spectrum, where total yield and spectral selectivity in the XUV are the targets of the optimization approach. The effect of using sulfur hexafluoride for pulse-shaping the XUV yield can be doubled compared to pulse compression and pulse-shaping using argon and the spectral range for selective optimization of a single harmonic can be extended. The obtained results are of interest for extending the range of ultrafast science applications drawing on tailored XUV fields.

  7. Sulfur Hexafluoride (SF6) Emission Estimates for China: An Inventory for 1990–2010 and a Projection to 2020

    OpenAIRE

    Janssens-Maenhout, Greet; Hu, Xia; Fang, Xuekun; Wu, Jing; Su, S; Zhang, J.; Hu, J.

    2013-01-01

    Sulfur hexafluoride (SF6) is the most potent greenhouse gas regulated under the Kyoto Protocol, with a high global warming potential. In this study, SF6 emissions f rom China were inventoried f or 1990–2010 and projected to 2020. Results reveal that the highest SF6 emission contribution originates f rom the electrical equipment sector (about 70%), f ollowed by the magnesium production sector, the semiconductor manufacture sector and the SF6 production sector (each about 10%). Both agreements ...

  8. Extremely Nonlinear Optics Using Shaped Pulses Spectrally Broadened in an Argon- or Sulfur Hexafluoride-Filled Hollow-Core Fiber

    OpenAIRE

    Andreas Hoffmann; Michael Zürch; Christian Spielmann

    2015-01-01

    In this contribution we present a comparison of the performance of spectrally broadened ultrashort pulses using a hollow-core fiber either filled with argon or sulfur hexafluoride (SF6) for demanding pulse-shaping experiments. The benefits of both gases for pulse-shaping are studied in the highly nonlinear process of high-harmonic generation. In this setup, temporally shaping the driving laser pulse leads to spectrally shaping of the output extreme ultraviolet (XUV) spectrum, where total yie...

  9. Field experiment on 222Rn flux from reclaimed uranium tailings

    International Nuclear Information System (INIS)

    Design and construction techniques are described for a 1.6 ha experimental uranium mill tailings reclamation plot. A passive, activated charcoal device was developed and tested for measurements of radon flux. Experiments on radon flux versus overburden depth showed that tailings covered with 1.5 m of revegetated or 0.3 m of bare overburden had exhalation rates comparable to background. Vegetated subplots exhibited a significantly higher (often an order of magnitude) flux than the bare subplots. Results on the variation of flux over time did not reveal any definitive patterns, possibly due to the high variability among replicates. A positive correlation was demonstrated between precipitation and radon flux. This is discussed in detail and possibly explained by the increase in water content of the micropores within the tailings, which increases the emanation coefficient without adversely effecting the diffusion coefficient of the overburden. 30 references, 7 figures, 3 tables

  10. Field Investigations of Evaporation from a Bare Soil

    Science.gov (United States)

    Evett, Steven Roy

    Selected components of the water and energy balances at the surface of a bare clay loam were measured at 57 locations in a 1 ha field. Spatial and temporal variability of these components were also studied. Components included evaporation, irrigation, moisture storage, sensible heat flux and long wave radiation. Sub-studies were conducted on irrigation uniformity under low pressure sprinklers; and, on steel versus plastic microlysimeters (ML) of various lengths. An energy balance model of evaporation, requiring minimal inputs, was developed and validated giving an r ^2 value of 0.78. Model improvements included an easy method of accurately estimating soil surface temperature at many points in a field, and an empirically fitted transfer coefficient function for the sensible heat flux from the reference dry soil. The omission of soil heat flux and reflected shortwave radiation terms was shown to reduce model accuracy. Steel ML underestimated cumulative evaporation compared to plastic ML at 20 and 30 cm lengths. Cumulative evaporation increased with ML length. The 10 and 20 cm ML were too short for use over multiple days but 30 cm ML may not be long enough for extended periods. Daily net soil heat flux for steel ML averaged 44% higher than that for both plastic ML and undisturbed field soil. Christiansen's uniformity coefficient (UCC) was close to 0.83 for each of 3 irrigations when measured by both catch cans and by profile water contents. But UCC for the change in storage due to irrigation averaged only 0.43 indicating than the high uniformity of profile water contents was more due to surface and subsurface redistribution than to the uniformity of application. Profile water contents and catch can depths were time invariant across at least 3 irrigations. Midday soil surface temperatures and daily evaporation were somewhat less time invariant. Variogram plots for evaporation and surface temperature showed mostly random behavior. Relative variograms represented well

  11. Microbial interactions with uranium: implications for uranium bioremediation

    International Nuclear Information System (INIS)

    Accidental release of uranium into the environment has the potential of inducing chemical and radiological toxicity. In situ bioremediation of uranium by microbial processes has been shown to be effective for immobilizing uranium in contaminated sites. Such microbial processes are important components of biogeochemical cycles and regulate the mobility and fate of uranium in the environment. This talk focuses on the spectrum of mechanisms displayed by various microorganisms in order to alleviate uranium toxicity which forms the basis of uranium bioremediation. (author)

  12. Uranium enrichment. Principles

    International Nuclear Information System (INIS)

    Uranium enrichment industry is a more than 60 years old history and has developed without practically no cost, efficiency or profit constraints. However, remarkable improvements have been accomplished since the Second World War and have led to the development of various competing processes which reflect the diversity of uranium compositions and of uranium needs. Content: 1 - general considerations: uranium isotopes, problem of uranium enrichment, first realizations (USA, Russia, Europe, Asia, other countries), present day situation, future needs and market evolution; 2 - principles of isotopic separation: processes classification (high or low enrichment), low elementary enrichment processes, equilibrium time, cascade star-up and monitoring, multi-isotopes case, uranium reprocessing; 3 - enrichment and proliferation. (J.S.)

  13. Uranium Newsletter. No. 1

    International Nuclear Information System (INIS)

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

  14. Uses of depleted uranium

    International Nuclear Information System (INIS)

    The depleted uranium is that in which percentage of uranium-235 fission executable is less than 0.2% or 0.3%. It is usually caused by the process of reprocessing the nuclear fuel burning, and also mixed with some other radioactive elements such as uranium 236, 238 and plutonium 239. The good features of the depleted uranium are its high density, low price and easily mined. So, the specifications for depleted uranium make it one of the best materials in case you need to have objects small in size, but quite heavy regarding its size. Uses of deplet ed uranium were relatively increased in domestic industrial uses as well as some uses in nuclear industry in the last few years. So it has increased uses in many areas of military and peaceful means such as: in balancing the giant air crafts, ships and missiles and in the manufacture of some types of concrete with severe hardness. (author)

  15. Uranium purchases report 1992

    International Nuclear Information System (INIS)

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

  16. Geochemical exploration for uranium

    International Nuclear Information System (INIS)

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

  17. Uranium: A Dentist's perspective

    OpenAIRE

    Toor, R. S. S.; Brar, G S

    2012-01-01

    Uranium is a naturally occurring radionuclide found in granite and other mineral deposits. In its natural state, it consists of three isotopes (U-234, U-235 and U-238). On an average, 1% – 2% of ingested uranium is absorbed in the gastrointestinal tract in adults. The absorbed uranium rapidly enters the bloodstream and forms a diffusible ionic uranyl hydrogen carbonate complex (UO2HCO3+) which is in equilibrium with a nondiffusible uranyl albumin complex. In the skeleton, the uranyl ion repla...

  18. Uranium in Canada

    International Nuclear Information System (INIS)

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

  19. Uranium industry annual, 1988

    International Nuclear Information System (INIS)

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

  20. Biogeochemistry of uranium

    International Nuclear Information System (INIS)

    The possible receipt of uranium from poor ores with application of biotechnology and use of microorganisms is presented. A particular attention is paid to mechanisms of bacterium leaching of uranium and to factors that influence the efficiency of this process and also, to tolerance of microorganisms to toxic metals. Processes of uranium biosorption from a sea water by algae, mushrooms and bacteria are also described. 36 refs. (author)

  1. Simulating distinguish enriched uranium from depleted uranium by activation method

    International Nuclear Information System (INIS)

    Detecting uranium material is an important work in arms control Active detection is an efficient method for uranium material. The paper focuses on the feasibility that can distinguish the enriched uranium and the depleted uranium by MCNP program. It can distinguish the enriched uranium and the depleted uranium by the curve of relationship between fission rate of uranium material and thickness of moderator.Advantages of 252Cf and 14 MeV neutron sources are discussed in detecting uranium material through calculation. The results show that 252Cf neutron source is better than 14 MeV one. Delayed neutrons are more easily detected than delayed gamma ray at measurement aspect. (authors)

  2. CHEMICAL TOXICITY OF URANIUM

    OpenAIRE

    2007-01-01

    Uranium, occurs naturally in the earth’s crust, is an alpha emitter radioactive element from the actinide group. For this reason, U-235 and U-238, are uranium isotopes with long half lives, have got radiological toxicity. But, for natural-isotopic-composition uranium (NatU), there is greater risk from chemical toxicity than radiological toxicity. When uranium is get into the body with anyway, also its chemical toxicity must be thought. [TAF Prev Med Bull 2007; 6(3.000): 215-220

  3. Uranium and drinking water

    International Nuclear Information System (INIS)

    Uranium is provoking public anxiety based on the radioactivity of several isotopes and the connection to nuclear technology. Drinking water contains at the most geogenic uranium in low concentrations that might be interesting in the frame of chemical of toxicology, but not due to radiological impact. The contribution gives an overview on the uranium content in drinking water and health effects for the human population based on animal tests. These experiments indicate a daily tolerable intake of 0.2 microgram per kg body mass. The actual limiting value for uranium in drinking water is 0.3 microgram per kg body mass water (drinking water regulation from 2001).

  4. CHEMICAL TOXICITY OF URANIUM

    Directory of Open Access Journals (Sweden)

    Sermin Cam

    2007-06-01

    Full Text Available Uranium, occurs naturally in the earth’s crust, is an alpha emitter radioactive element from the actinide group. For this reason, U-235 and U-238, are uranium isotopes with long half lives, have got radiological toxicity. But, for natural-isotopic-composition uranium (NatU, there is greater risk from chemical toxicity than radiological toxicity. When uranium is get into the body with anyway, also its chemical toxicity must be thought. [TAF Prev Med Bull 2007; 6(3.000: 215-220

  5. International trade in uranium

    International Nuclear Information System (INIS)

    Two reports are presented; one has been prepared by the Uranium Institute and is submitted by the United Kingdom delegation, the other by the United States delegation. The report of the Uranium Institute deals with the influence of the government on international trade in uranium. This influence becomes apparent predominantly by export and import restrictions, as well as by price controls. The contribution submitted by the United States is a uranium market trend analysis, with pricing methods and contracting modes as well as the effect of government policies being investigated in the light of recent developments

  6. Phospholyl-uranium complexes

    International Nuclear Information System (INIS)

    After having reported a bibliographical study on penta-methylcyclopentadienyl uranium complexes, and a description of the synthesis and radioactivity of uranium (III) and (IV) boron hydrides compounds, this research thesis reports the study of mono and bis-tetramethyl-phospholyl uranium complexes comprising chloride, boron hydride, alkyl and alkoxide ligands. The third part reports the comparison of structures, stabilities and reactions of homologue complexes in penta-methylcyclopentadienyl and tetramethyl-phospholyl series. The last part addresses the synthesis of tris-phospholyl uranium (III) and (IV) complexes.

  7. Uranium production from phosphates

    International Nuclear Information System (INIS)

    According to estimates of the world's uranium consumption, exploitation of most rich sources is expected by the 1980's. Forecasts show that the rate of uranium consumption will increase towards the end of the century. It is therefore desirable to exploit poor sources not yet in use. In the near future, the most reasonable source for developing uranium is phosphate rock. Uranium reserves in phosphates are estimated at a few million tons. Production of uranium from phosphates is as a by-product of phosphate rock processing and phosphoric acid production; it will then be possible to save the costs incurred in crushing and dissolving the rock when calculating uranium production costs. Estimates show that the U.S. wastes about 3,000 tons of uranium per annum in phosphoric acid based fertilisers. Studies have also been carried out in France, Yugoslavia and India. In Israel, during the 1950's, a small plant was operated in Haifa by 'Chemical and Phosphates'. Uranium processes have also been developed by linking with the extraction processes at Arad. Currently there is almost no activity on this subject because there are no large phosphoric acid plants which would enable production to take place on a reasonable scale. Discussions are taking place about the installation of a plant for phosphoric acid production utilising the 'wet process', producing 200 to 250,000 tons P2O5 per annum. It is necessary to combine these facilities with uranium production plant. (author)

  8. Heating uranium alloy billets

    International Nuclear Information System (INIS)

    Data were obtained for the surface heat transfer coefficient of uranium and the alloys of uranium-0.75 wt percent titanium, uranium-6 wt percent niobium, and uranium-7.5 wt percent niobium-2.5 wt percent zirconium. Samples were heated to 8500C in both a molten salt bath and an argon-purged air furnace, then the samples were cooled in air. Surface heat transfer coefficients were calculated from the experimental data for both heating and cooling of the metals. 4 fig, 4 tables

  9. Standard test method for determination of impurities in nuclear grade uranium compounds by inductively coupled plasma mass spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method covers the determination of 67 elements in uranium dioxide samples and nuclear grade uranium compounds and solutions without matrix separation by inductively coupled plasma mass spectrometry (ICP-MS). The elements are listed in Table 1. These elements can also be determined in uranyl nitrate hexahydrate (UNH), uranium hexafluoride (UF6), triuranium octoxide (U3O8) and uranium trioxide (UO3) if these compounds are treated and converted to the same uranium concentration solution. 1.2 The elements boron, sodium, silicon, phosphorus, potassium, calcium and iron can be determined using different techniques. The analyst's instrumentation will determine which procedure is chosen for the analysis. 1.3 The test method for technetium-99 is given in Annex A1. 1.4 The values stated in SI units are to be regarded as standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish ...

  10. Summary of results from the Series 2 and Series 3 NNWSI [Nevada Nuclear Waste Storage Investigations] bare fuel dissolution tests

    International Nuclear Information System (INIS)

    The Nevada Nuclear Waste Storage Investigations (NNWSI) Project is studying dissolution and radionuclide release behavior of spent nuclear fuel in Nevada Test Site groundwater. Specimens were tested for multiple cycles in J-13 well water. The Series 2 tests were run in unsealed silica vessels under ambient hot cell air (250C) for five cycles for a total of 34 months. The Series 3 tests were run in sealed stainless steel vessels at 250C and 850C for three cycles for a total of 15 months. Selected summary results from Series 2 and Series 3 tests with bare fuel specimens are reported. Uranium concentrations in later test cycles ranged from 1 to 2 μg/ml in the Series 2 Tests versus about 0.1 to 0.4 μg/ml in Series 3 with the lowest concentrations occurring in the 850C tests. Preferential release of fission products Cs, I, Sr and Tc, and activation product C-14, was indicated relative to the actinides. Tc-99 and Cs-137 activities measured in solution after Cycle 1 increased linearly with time, with the rate of increase greater at 850C than at 250C. 8 refs., 8 figs., 3 tabs

  11. Size dependence of the bandgap of plasma synthesized silicon nanoparticles through direct introduction of sulfur hexafluoride

    Science.gov (United States)

    Theingi, S.; Guan, T. Y.; Kendrick, C.; Klafehn, G.; Gorman, B. P.; Taylor, P. C.; Lusk, M. T.; Stradins, P.; Collins, R. T.

    2015-10-01

    Developing silicon nanoparticle (SiNP) synthesis techniques that allow for straightforward control of nanoparticle size and associated optical properties is critical to potential applications of these materials. In addition, it is, in general, hard to probe the absorption threshold in these materials due to silicon's low absorption coefficient. In this study, size is controlled through direct introduction of sulfur hexafluoride (SF6) into the dilute silane precursor of plasma synthesized SiNPs. Size reduction by nearly a factor of two with high crystallinity independent of size is demonstrated. The optical absorption spectra of the SiNPs in the vicinity of the bandgap are measured using photothermal deflection spectroscopy. Bandgap as a function of size is extracted taking into account the polydispersity of the samples. A systematic blue shift in absorption edge due to quantum confinement in the SiNPs is observed with increasing flow of SF6. Photoluminescence (PL) spectra show a similar blue shift with size. However, a ˜300 meV difference in energy between emission and absorption for all sizes suggests that PL emission involves a defect related process. This shows that, while PL may allow size-induced shifts in the bandgap of SiNPs to be monitored, it cannot be relied on to give an accurate value for the bandgap as a function of size.

  12. Numerical study to assess sulfur hexafluoride as a medium for testing multielement airfoils

    Science.gov (United States)

    Bonhaus, Daryl L.; Anderson, W. Kyle; Mavriplis, Dimitri J.

    1995-01-01

    A methodology is described for computing viscous flows of air and sulfur hexafluoride (SF6). The basis is an existing flow solver that calculates turbulent flows in two dimensions on unstructured triangular meshes. The solver has been modified to incorporate the thermodynamic model for SF6 and used to calculate the viscous flow over two multielement airfoils that have been tested in a wind tunnel with air as the test medium. Flows of both air and SF6 at a free-stream Mach number of 0.2 and a Reynolds number of 9 x 10(exp 6) are computed for a range of angles of attack corresponding to the wind-tunnel test. The computations are used to investigate the suitability of SF6 as a test medium in wind tunnels and are a follow-on to previous computations for single-element airfoils. Surface-pressure, lift, and drag coefficients are compared with experimental data. The effects of heavy gas on the details of the flow are investigated based on computed boundary-layer and skin-friction data. In general, the predictions in SF6 vary little from those in air. Within the limitations of the computational method, the results presented are sufficiently encouraging to warrant further experiments.

  13. Size dependence of the bandgap of plasma synthesized silicon nanoparticles through direct introduction of sulfur hexafluoride

    Energy Technology Data Exchange (ETDEWEB)

    Theingi, S.; Guan, T. Y.; Klafehn, G.; Taylor, P. C.; Lusk, M. T.; Collins, R. T., E-mail: rtcollin@mines.edu [Department of Physics, Colorado School of Mines, Golden, Colorado 80401 (United States); Renewable Energy Materials Research Science and Engineering Center, Colorado School of Mines, Golden, Colorado 80401 (United States); Kendrick, C. [Department of Physics, Colorado School of Mines, Golden, Colorado 80401 (United States); Renewable Energy Materials Research Science and Engineering Center, Colorado School of Mines, Golden, Colorado 80401 (United States); Electrical and Computer Engineering, Michigan Technological University, Houghton, Michigan 49931 (United States); Gorman, B. P. [Metallurgical and Materials Engineering, Colorado School of Mines, Golden, Colorado 80401 (United States); Stradins, P. [Renewable Energy Materials Research Science and Engineering Center, Colorado School of Mines, Golden, Colorado 80401 (United States); National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)

    2015-10-19

    Developing silicon nanoparticle (SiNP) synthesis techniques that allow for straightforward control of nanoparticle size and associated optical properties is critical to potential applications of these materials. In addition, it is, in general, hard to probe the absorption threshold in these materials due to silicon's low absorption coefficient. In this study, size is controlled through direct introduction of sulfur hexafluoride (SF{sub 6}) into the dilute silane precursor of plasma synthesized SiNPs. Size reduction by nearly a factor of two with high crystallinity independent of size is demonstrated. The optical absorption spectra of the SiNPs in the vicinity of the bandgap are measured using photothermal deflection spectroscopy. Bandgap as a function of size is extracted taking into account the polydispersity of the samples. A systematic blue shift in absorption edge due to quantum confinement in the SiNPs is observed with increasing flow of SF{sub 6}. Photoluminescence (PL) spectra show a similar blue shift with size. However, a ∼300 meV difference in energy between emission and absorption for all sizes suggests that PL emission involves a defect related process. This shows that, while PL may allow size-induced shifts in the bandgap of SiNPs to be monitored, it cannot be relied on to give an accurate value for the bandgap as a function of size.

  14. Size Dependence of the Bandgap of Plasma Synthesized Silicon Nanoparticles Through Direct Introduction of Sulfur Hexafluoride

    Energy Technology Data Exchange (ETDEWEB)

    Theingi, S.; Guan, T. Y.; Kendrick, C.; Klafehn, G.; Gorman, B. P.; Taylor, P. C.; Lusk, M. T.; Stradins, Pauls; Collins, R. T.

    2015-10-19

    Developing silicon nanoparticle (SiNP) synthesis techniques that allow for straightforward control of nanoparticle size and associated optical properties is critical to potential applications of these materials. In addition, it is, in general, hard to probe the absorption threshold in these materials due to silicon's low absorption coefficient. In this study, size is controlled through direct introduction of sulfur hexafluoride (SF6) into the dilute silane precursor of plasma synthesized SiNPs. Size reduction by nearly a factor of two with high crystallinity independent of size is demonstrated. Optical absorption spectra of the SiNPs in the vicinity of the bandgap are measured using photothermal deflection spectroscopy. Bandgap as a function of size is extracted taking into account the polydispersity of the samples. A systematic blue shift inabsorption edge due to quantum confinement in the SiNPs is observed with increasing flow of SF6. Photoluminescence (PL) spectra show a similar blue shift with size. However, a ~300 meV difference in energy between emission and absorption for all sizes suggests that PL emission involves a defect related process. While PL may allow size-induced shifts in the bandgap of SiNPs to be monitored, it cannot be relied on to give an accurate value for the bandgap as a function of size.

  15. A search for the sulphur hexafluoride cation with intense, few cycle laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Dota, Krithika; Mathur, Deepak, E-mail: atmol1@tifr.res.in [Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400 005 (India); Centre for Atomic and Molecular Physics, Manipal University, Manipal 576 104 (India); Dharmadhikari, Aditya K. [Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400 005 (India); Dharmadhikari, Jayashree A. [Centre for Atomic and Molecular Physics, Manipal University, Manipal 576 104 (India); Patra, Kaustuv; Tiwari, Ashwani K. [Indian Institute of Science Education and Research - Kolkata, Mohanpur 741 252 (India)

    2013-11-21

    It is well established that upon ionization of sulphur hexafluoride, the SF{sub 6}{sup +} ion is never observed in mass spectra. Recent work with ultrashort intense laser pulses has offered indications that when strong optical field are used, the resulting “bond hardening” can induce changes in the potential energy surfaces of molecular cations such that molecular ions that are normally unstable may, indeed, become metastable enough to enable their detection by mass spectrometry. Do intense, ultrashort laser pulses permit formation of SF{sub 6}{sup +}? We have utilized intense pulses of 5 fs, 11 fs, and 22 fs to explore this possibility. Our results are negative: no evidence is discovered for SF{sub 6}{sup +}. However, multiply charged sulphur and fluorine ions from highly charged SF{sub 6}{sup q+} ions are observed that enable us to resolve the controversy regarding the kinetic energy release accompanying formation of F{sup +} fragment ions. Quantum chemical computations of field-distorted potential energy curves of SF{sub 6} and its molecular ion enable us to rationalize our non-observation of SF{sub 6}{sup +}. Our findings have implications for high harmonic generation from SF{sub 6} in the few-cycle regime.

  16. Screening test of relays used under pressurized sulfur hexafluoride (SF6)

    International Nuclear Information System (INIS)

    Many measurement and control devices inside of a high voltage terminal of the JAEA-Tokai tandem accelerator are operated under pressurized sulfur hexafluoride gas (SF6) of 0.5 MPa. This screening test has been carried out to select a relay, which is usable under the pressurized SF6 for turn on and off a large current of the devices, from commercial relays used in the atmospheric condition. Four kinds of relays were tested: electromechanical relay (EMR), magnet contactor (MAG), solid-state relay (SSR) and hybrid relay (HYB). Temperature and appearance changes of the relay were collected as measurement items. In addition, a reason of contact trouble of the relays was considered from the results of qualitative elementary analysis and observation of the contact surface using the EDS (energy-dispersive X-ray spectroscopy) and the SEM (scanning electron microscope). As a result, the EMR and the MAG showed irregular contact in spite of input voltage and electric current had fed to an operational coil of the relay normally. It is caused by the sulfide or fluoride compounds, which were formed by chemical reaction between metals and sulfur or hydrogen fluoride due to dissociation of SF6 in electric arcs. On the other hand, the performance of the SSR and the HYB is better than the EMR and the MAG, and it was found that these relays are available in the pressurized SF6 of 0.5MPa in spite of the standard specification. (author)

  17. Sulfur hexafluoride reprocessing system design for a large pulsed power accelerator

    International Nuclear Information System (INIS)

    The Particle Beam Fusion Accelerator-II (PBFA-II) is a large, high power accelerator being constructed at Sandia National Labs to conduct research in inertial confinement fusion. One key to the success of this machine is the ability to produce an electrical pulse at the target with a well defined shape (power versus time). This requires that the 36 electrical drivers be initiated with good simultaneity. Simultaneity (or jitter) of the 36 module shot outputs is controlled by a sequence of pulse outputs starting at the control/monitor input to the trigger amplifier and then to the Marx trigger generators, the Marx generators, and finally the rimfire switches. A homogeneous insulating vapor in these switches is thought to reduce the jitter; however, actual data are not available to establish this concept. PBFA-II uses sulfur hexafluoride (SF6) for this insulating vapor. This paper describes the requirements placed on an SF6 reprocessing system when operating in a fusion research accelerator, resulting in criteria used to design the reprocessing system, and the subsequent design implemented to meet these criteria

  18. The variability of methane, nitrous oxide and sulfur hexafluoride in Northeast India

    Science.gov (United States)

    Ganesan, A. L.; Chatterjee, A.; Prinn, R. G.; Harth, C. M.; Salameh, P. K.; Manning, A. J.; Hall, B. D.; Mühle, J.; Meredith, L. K.; Weiss, R. F.; O'Doherty, S.; Young, D.

    2013-11-01

    High-frequency atmospheric measurements of methane (CH4), nitrous oxide (N2O) and sulfur hexafluoride (SF6) from Darjeeling, India are presented from December 2011 (CH4)/March 2012 (N2O and SF6) through February 2013. These measurements were made on a gas chromatograph equipped with a flame ionization detector and electron capture detector, and were calibrated on the Tohoku University, the Scripps Institution of Oceanography (SIO)-98 and SIO-2005 scales for CH4, N2O and SF6, respectively. The observations show large variability and frequent pollution events in CH4 and N2O mole fractions, suggesting significant sources in the regions sampled by Darjeeling throughout the year. By contrast, SF6 mole fractions show little variability and only occasional pollution episodes, likely due to weak sources in the region. Simulations using the Numerical Atmospheric dispersion Modelling Environment (NAME) particle dispersion model suggest that many of the enhancements in the three gases result from the transport of pollutants from the densely populated Indo-Gangetic Plains of India to Darjeeling. The meteorology of the region varies considerably throughout the year from Himalayan flows in the winter to the strong south Asian summer monsoon. The model is consistent in simulating a diurnal cycle in CH4 and N2O mole fractions that is present during the winter but absent in the summer and suggests that the signals measured at Darjeeling are dominated by large-scale (~100 km) flows rather than local (<10 km) flows.

  19. Adsorption equilibrium of sulfur hexafluoride on multi-walled carbon nanotubes

    International Nuclear Information System (INIS)

    The adsorption of sulfur hexafluoride (SF6) on multi-walled carbon nanotubes (MWNTs) was investigated. The properties of MWNTs were characterized and the adsorption capacities of SF6 on MWNTs at different concentrations and temperatures were collected. H2SO4/H2O2 oxidation or KOH activation of MWNTs has effectively introduced the surface oxides and modified the microstructure without destruction of their graphitic crystalline structure. The MWNTs, especially the modified samples, are expected to be promising adsorbents for SF6 removals from air. The saturated capacities of SF6 with a concentration of 518 ppmv on the MWNTs ranged from 278 to 497 mg/g at 25 deg. C. The Toth equation has been reported to fit the adsorption data better than the Freundlich or Langmuir equation. The π-π dispersion interaction followed by the multi-layer adsorption and the electron donor-acceptor interaction were proposed to be the major adsorption mechanisms, depending on the adsorption temperature. The isosteric heat of adsorption, ranging from 51 to 124 kJ/mol with a loading of 30-300 mg/g, decreased with increasing SF6 loading, reflecting the energetic heterogeneity of the MWNTs. These results suggest that the adsorption of SF6 on MWNTs could be associated with binding to defect sites.

  20. Uranium industry annual 1993

    International Nuclear Information System (INIS)

    Uranium production in the United States has declined dramatically from a peak of 43.7 million pounds U3O8 (16.8 thousand metric tons uranium (U)) in 1980 to 3.1 million pounds U3O8 (1.2 thousand metric tons U) in 1993. This decline is attributed to the world uranium market experiencing oversupply and intense competition. Large inventories of uranium accumulated when optimistic forecasts for growth in nuclear power generation were not realized. The other factor which is affecting U.S. uranium production is that some other countries, notably Australia and Canada, possess higher quality uranium reserves that can be mined at lower costs than those of the United States. Realizing its competitive advantage, Canada was the world's largest producer in 1993 with an output of 23.9 million pounds U3O8 (9.2 thousand metric tons U). The U.S. uranium industry, responding to over a decade of declining market prices, has downsized and adopted less costly and more efficient production methods. The main result has been a suspension of production from conventional mines and mills. Since mid-1992, only nonconventional production facilities, chiefly in situ leach (ISL) mining and byproduct recovery, have operated in the United States. In contrast, nonconventional sources provided only 13 percent of the uranium produced in 1980. ISL mining has developed into the most cost efficient and environmentally acceptable method for producing uranium in the United States. The process, also known as solution mining, differs from conventional mining in that solutions are used to recover uranium from the ground without excavating the ore and generating associated solid waste. This article describes the current ISL Yang technology and its regulatory approval process, and provides an analysis of the factors favoring ISL mining over conventional methods in a declining uranium market