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

International Nuclear Information System (INIS)

Schnautz, N.G.; Venter, P.J.

1992-01-01

The reaction between uranium hexafluoride (UF 6 ) 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 UF 6 to afford the alkoxy uranium pentafluoride intermediate ROUF 5 , which reacts further to give the dehydration, deoxygenative fluorination, and ether products. In each of the above three reaction pathways, UF 6 is transformed to UOF 4 , which being as reactive toward alcohols as UF 6 , reacts further with the alcohol in question to finally afford the unreactive uranyl fluoride (UO 2 F 2 ). 6 refs., 2 tabs

Dynamic tests for qualifying of national uranium hexafluoride

International Nuclear Information System (INIS)

Araujo Figueiredo, C. de; Abreu Mendonca Schvartzman, M.M. de; Vasconcelos, M.C.R.L.

1990-01-01

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 UF 6 and H 2 . The process gas (UF 6 /H 2 ) 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 UF 6 has the same dynamic behaviour of the German UF 6 . It does not contain either any catalyst of the reaction between UF 6 and H 2 which could render it inappropriate for use in commercial plants. (author) [pt

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

International Nuclear Information System (INIS)

Hartmann, H.

2001-01-01

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 (UF 6 ) 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 UF 6 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

Depleted uranium hexafluoride management program : data compilation for the Portsmouth site

International Nuclear Information System (INIS)

Hartmann, H. M.

2001-01-01

This report is a compilation of data and analyses for the Portsmouth site, near Portsmouth, Ohio. 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 Portsmouth site and summarizes potential environmental impacts that could result from conducting the following depleted uranium hexafluoride (UF 6 ) management 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 UF 6 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

New regulatory aspects of UF6 transport

International Nuclear Information System (INIS)

Biaggio, A.L.; Lee Gonzales, H.M.; Lopez Vietri, J.R.; Novo, R.G.

1987-01-01

In nuclear industry, a great amount of uranium is transformed from a chemical form to another. When the fuel cycle requires enrichment, uranium hexafluoride (UF 6) is handled, stored and transported in great quantities. To analyze the risks involved in possible accidents associated with UF 6 , radiological and chemical aspects must be considered. So far, the international practice was based on the adoption of regulations from a particular country (ANSI No. 14.1-1982.U.S.A.). In this way, the adoption of these norms at international level is difficult. For that reason, the International Atomic Energy Agency has attempted to consider the chemical risks associated with UF 6 in order to establish a more universal basis ('Recommendations for Providing Protection during the Transport of Uranium Hexafluoride' IAEA-TECDOC-423, Vienna, June 1987 - Austria). A critical analysis of these recommendations is presented in this work. The coherence and the degree of completion of the new recommendations are evaluated and the safety level is compared with that of the accepted regulations for toxic or corrosive substances and for radioactive materials transport. (Author)

Analysis of accidental UF6 releases

International Nuclear Information System (INIS)

Fan Yumao; Tan Rui; Gao Qifa

2012-01-01

As interim substance in the nuclear fuel enrichment process, Uranium Hexafluoride (UF 6 ) is widely applied in nuclear processing, enrichment and fuel fabrication plants. Because of its vivid chemical characteristics and special radiological hazard and chemical toxicity, great attention must be paid to accident of UF 6 leakage. The chemical reactions involved in UF 6 release processes were introduced, therewith potential release styles, pathways and characteristics of diffusion were analyzed. The results indicated that the accidental release process of UF 6 is not a simple passive diffusion. So, specific atmospheric diffusion model related to UF 6 releases need be used in order to analyze and evaluate accurately the accidental consequences. (authors)

The physical and chemical properties of uranium hexafluoride

International Nuclear Information System (INIS)

Barber, E.J.

1988-01-01

This paper describes what uranium hexafluoride (UF 6 ) is, gives some of its pertinent physical properties, illustrates significant reactions between UF 6 and other substances, touches on its toxic properties, and states some of the ''do's'' and ''don't's'' of UF 6 handling. The properties of UF 6 determine how it must be handled and make direct observation impossible. To determine that the material in a container is UF 6 , one must use other instruments in addition to a scale. Because of the very large volume expanision of UF 6 upon melting, diligence must be exercised in filling cylinders in which the UF 6 is partially solidified. A cylinder of liquified UF 6 with no ullage is potentially the equivalent of a superheated hot water heater, not just a hydraulically overpressurized cylinder. Finally, UF 6 can be handled safely by careful attention to the suggested precautions. 9 refs., 2 tabs., 3 figs

Study of reactions for the production of uranium titrafluoride and uranium hexafluoride

International Nuclear Information System (INIS)

Guzella, M.F.R.

1985-01-01

The main production processes of uranium hexafluoride in pilot plants and industrial facilities are described. The known reactions confirmed in laboratory experiments that lead to Uf 6 or other intermediate fluorides are discussed. For the purpose of determining a thermodinamically feasible reaction involving the sulfur hexafluoride as fluorinating agent, a mock-up facility was designed and constructed as a part of the R and D work planned at the CDTN (Nuclebras Center for Nuclear Technology Development). IN the uranium tatrafluoride synthesis employing U 3 O 8 and SF 6 several experimental parameters are studied. The reaction time, gasflow, temperature and stoechiometic relations among reagents are described in detail. (Author) [pt

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.

Uranium hexafluoride: handling procedures and container criteria

International Nuclear Information System (INIS)

1977-04-01

The U.S. Energy Research and Development Administration's (ERDA) procedures for packaging, measuring, and transferring uranium hexafluoride (UF 6 ) have been undergoing continual review and revision for several years to keep them in phase with developing agreements for the supply of enriched uranium. This report, first issued in 1966, was reissued in 1967 to make editorial changes and to provide for 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. This document, Revision 4, includes primarily revisions to UF 6 cylinders, valves, and methods of use. This revision supersedes all previous issues of this report. The procedures will normally apply in all transactions involving receipt or shipment of UF 6 by ERDA, unless stipulated otherwise by contracts or agreements with ERDA or by notices published in the Federal Register

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

International Nuclear Information System (INIS)

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

1995-01-01

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

Reaction between uranium hexafluoride and trimethylsilylhalides

Energy Technology Data Exchange (ETDEWEB)

Brown, D; Berry, J A [UKAEA Atomic Energy Research Establishment, Harwell. Chemistry Div.; Holloway, J H; Staunton, G M [Leicester Univ. (UK). Dept. of Chemistry

1938-07-01

Reactions involving 1.1:1 molar ratios of uranium hexafluoride to either trimethylsilylchloride or trimethylsilylbromide in halocarbon solutions yield ..beta..-UF/sub 5/ at room temperature. With 2 mol equivalents of trimethylsilylchloride the product is UF/sub 4/. The reactions appear to proceed via the intermediate formation of unstable brown uranium(VI) chloride and bromide fluorides. Calculations show that UClF/sub 5/ and UCl/sub 2/F/sub 4/ are thermodynamically unstable with respect to the loss of chlorine at room temperature.

Emission characteristics of uranium hexafluoride at high temperatures

International Nuclear Information System (INIS)

Krascella, N.L.

1976-01-01

An experimental study was conducted to ascertain the spectral characteristics of uranium hexafluoride (UF 6 ) and possible UF 6 thermal decomposition products as a function of temperature and pressure. Relative emission measurements were made for UF 6 /Argon mixtures heated in a plasma torch over a range of temperatures from 800 to about 3600 0 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 0 K. Total pressure for these measurements was 1.0 atm

Method for separation of uranium hexafluoride by specially activated carbons

International Nuclear Information System (INIS)

Bannasch, W.

1976-01-01

The present invention deals with the separation of urainium hexafluoride from gas streams on special activated carbon which can be released during an accident in nuclear plants. Those plants are concerned here in which as a rule uranium hexafluoride is handled in liquid aggregate state. The patent claims deal with the adsorption of UF 6 from gas mixtures in the temperature region of 70-200 0 C and the application of UF 6 adsorbing activated carbon of a certain grain based on petroleum and/or weight % and with a asch content of 4 to 6 weigt % and with a benzol yield of 50-60g benzene /100g activated carbon. (GG) [de

Study of the molecular structure of uranium hexafluoride

International Nuclear Information System (INIS)

Bougon, R.

1967-06-01

The vibrational spectrum of uranium hexafluoride has been studied in both the gaseous and solid states. The study of gaseous UF 6 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 UF 6 ; this distortion has only observed up till now by means of X-ray diffraction and nuclear magnetic resonance techniques. (author) [fr

Kinetics of gaseous uranium hexafluoride reaction with hydrogen chloride

International Nuclear Information System (INIS)

Ezubchenko, A.N.; Ilyukhin, A.I.; Merzlyakov, A.V.

1993-01-01

Kinetics of decrease of concentration of gaseous uranium hexafluoride in reaction with hydrogen chloride at temperatures close to room ones, was investigated by the method of IR spectroscopy. It was established that the process represented the first order reaction by both UF 6 and HCl. Activation energy of the reaction was determined: 7.6 ± 0.7 kcal/mol. Specific feature of reaction kinetics was noted: inversely proportional dependence of effective constant on UF 6 initial pressure. 5 refs., 3 figs

CFD-simulation of uranium hexafluoride during phase change

International Nuclear Information System (INIS)

Pakarinen, Tomi

2014-01-01

A model for simulating the behavior of uranium hexafluoride during melting and solidification cycles has been developed. First goal was to create a user-defined material of uranium hexafluoride for commercial computational fluid dynamics software (FLUENT). The results of the thermo physical properties are presented in this paper. The material properties were used to create a model that is able to simulate melting, solidification, evaporation and condensation. The model was used to obtain knowledge of UF 6 s behaviour when melting and solidifying the matter in a two-dimensional cylinder. The results were compared to the results of an analytical solution. The calculation results are consistent with the simulation. (authors)

Depleted uranium hexafluoride: Waste or resource?

International Nuclear Information System (INIS)

Schwertz, N.; Zoller, J.; Rosen, R.; Patton, S.; Bradley, C.; Murray, A.

1995-07-01

The US Department of Energy is evaluating technologies for the storage, disposal, or re-use of depleted uranium hexafluoride (UF 6 ). This paper discusses the following options, and provides a technology assessment for each one: (1) conversion to UO 2 for use as mixed oxide duel, (2) conversion to UO 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 3 O 8 as an option for long-term storage is discussed

Thermodynamic properties of UF sub 6 measured with a ballistic piston compressor

Science.gov (United States)

Sterritt, D. E.; Lalos, G. T.; Schneider, R. T.

1973-01-01

From experiments performed with a ballistic piston compressor, certain thermodynamic properties of uranium hexafluoride were investigated. Difficulties presented by the nonideal processes encountered in ballistic compressors are discussed and a computer code BCCC (Ballistic Compressor Computer Code) is developed to analyze the experimental data. The BCCC unfolds the thermodynamic properties of uranium hexafluoride from the helium-uranium hexafluoride mixture used as the test gas in the ballistic compressor. The thermodynamic properties deduced include the specific heat at constant volume, the ratio of specific heats for UF6, and the viscous coupling constant of helium-uranium hexafluoride mixtures.

Minimizing the risk and impact of uranium hexafluoride production

International Nuclear Information System (INIS)

Clark, D.R.; Kennedy, T.W.

2010-01-01

Cameco Corporation's Port Hope conversion facility, situated on the shore of Lake Ontario in the Municipality of Port Hope, Ontario, Canada, converts natural uranium trioxide (UO_3) into uranium dioxide (UO_2) or natural uranium hexafluoride (UF_6). Conversion of UO_3 to UF_6 has been undertaken at the Port Hope conversion facility since 1970 and is currently carried out in a second-generation plant licensed to annually produce 12,500 tonnes U as UF_6. Consistent with Cameco's vision, values and measures of success, Cameco recognizes safety and health of its workers and the public, protection of the environment, and the quality of our processes as the highest corporate priorities. Production of UF_6 in a brownfield urban setting requires a commitment to design, build and maintain multiple layers of containment (defence-in-depth) and to continually improve in all operational aspects to achieve this corporate commitment. This paper will describe the conversion processes utilized with a focus on the cultural, management and physical systems employed to minimize the risk and impact of the operation. (author)

Status of overpacks for uranium hexafluoride transport

International Nuclear Information System (INIS)

Arendt, J.W.; Pryor, W.A.

1985-01-01

The original overpacks for uranium hexafluoride (UF 6 ) transport, which utilized phenolic foam insulation, were developed in the 1960's and ultimately became international standards. A second generation of overpacks for 10-ton-capacity UF 6 cylinders used polyurethane foam and was developed in the early 1970's. In the mid 1970's, a third generation was designed, but no attempt to develop it occurred until the early 1980's, when full-scale testing of an overpack for 14-ton capacity UF 6 cylinders was initiated and resulted in designs for a new family of UF 6 overpacks. In the meantime, two additional developments affected overpack use for UF 6 cylinder transport: (1) the discovery that phenolic-foam-insulated overpacks have water absorption and outleakage problems inaugurated a program for their improvement and (2) new polyurethane-insulated overpacks were manufactured. The current status of all these overpacks, including their designs, testing, and approval for transport is presented

Uranium hexafluoride: Handling procedures and container descriptions

International Nuclear Information System (INIS)

1987-09-01

The US Department of Energy (DOE) guidelines for packaging, measuring, and transferring uranium hexafluoride (UF 6 ) 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 UF 6 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 UF 6 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 UF 6 ) 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 UF 6 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

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.

Depleted UF6 programmatic environmental impact statement

International Nuclear Information System (INIS)

1997-01-01

The US Department of Energy has developed a program for long-term management and use of depleted uranium hexafluoride, a product of the uranium enrichment process. As part of this effort, DOE is preparing a Programmatic Environmental Impact Statement (PEIS) for the depleted UF 6 management program. This report duplicates the information available at the web site (http://www.ead.anl.gov/web/newduf6) set up as a repository for the PEIS. Options for the web site include: reviewing recent additions or changes to the web site; learning more about depleted UF 6 and the PEIS; browsing the PEIS and related documents, or submitting official comments on the PEIS; downloading all or part of the PEIS documents; and adding or deleting one's name from the depleted UF 6 mailing list

Previsional evaluation of risks associated with ground transportation of uranium hexafluoride

International Nuclear Information System (INIS)

Pages, P.; Tomachevsky, E.

1987-11-01

This communication is a concrete example of application of the evaluation method for risks associated with road transportation of uranium hexafluoride by 48Y shipping container. The statistical bases for UF6 transportation are given by analysis of the list of accidents for dangerous road transportation. This study examines all parameters (cost-safety-meteorology-radiation doses) to take in account in the safety analysis of the UF6 transportation between Pierrelatte and Le Havre [fr

A study of UF4 preparations

International Nuclear Information System (INIS)

Chang, I.S.; Doh, J.B.; Choi, Y.D.

1985-05-01

Uranium tetrafluoride (UF 4 ), green salt, is very important intermediate in the production of metallic uranium and uranium hexafluoride (UF 6 ) for enrichment. The hydrofluorination of uranium dioxide (UO 2 ) with anhydrous hydrogen fluoride (HF), produced from ADU (ammonium diuranate) process or AUC (ammonium uranyl carbonate) process, are commercially used for the production of uranium tetrafluoride. At present, a new approach such as direct UF 4 preparation at the mine-site without further precipitation, filteration and drying of yellow cake from leaching solution has been studied. The single step continous reduction of uranium hexafluoride to uranium tetrafluoride is one of the most interesting process being applied for the commercial use of a large amount of depleted UF 6 which is produced in tail after enrichment. The direct conversion of UF 6 and UF 4 with hydrogen and fluorine gases using cold wall reactor has a certain advantage over various wet process such as AUD and AUC processes in which hydrolysis of UF 6 and various kind of chemicals are required, including liquid waste treatment. This report reviews and analyzes the theory and processes being used commercially or under study. (Author)

Thermal plasma reduction of UF6

International Nuclear Information System (INIS)

Fincke, J.R.; Swank, W.D.; Haggard, D.C.

1995-01-01

This paper describes the experimental demonstration of a process for the direct plasma reduction of depleted uranium hexafluoride to uranium metal. The process exploits the large departures from equilibrium that can be achieved in the rapid supersonic expansion of a totally dissociated and partially ionized mixture of UF 6 , Ar, He, and H 2 . The process is based on the rapid condensation of subcooled uranium vapor and the relatively slow rate of back reaction between metallic uranium and HF to F 2 to reform stable fluorides. The high translational velocities and rapid cooling result in an overpopulation of atomic hydrogen which persists throughout the expansion process. Atomic hydrogen shifts the equilibrium composition by inhibiting the reformation of uranium-fluorine compounds. This process has the potential to reduce the cost of reducing UF 6 to uranium metal with the added benefit of being a virtually waste free process. The dry HF produced is a commodity which has industrial value

Reuse of ammonium fluoride generated in the uranium hexafluoride conversion

International Nuclear Information System (INIS)

Silva Neto, J.B.; Carvalho, E.F. Urano de; Durazzo, M.; Riella, H.G

2010-01-01

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 3 Si 2 ) dispersed in aluminum. For producing the fuel, the processes for uranium hexafluoride (UF 6 ) conversion consist in obtaining U 3 Si 2 and / or U 3 O 8 through the preparation of intermediate compounds, among them ammonium uranyl carbonate - AUC, ammonium diuranate - DUA and uranium tetrafluoride - UF 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 4 + ), fluoride (F - ), carbonate (CO 3 -- ) and low concentrations of uranium. The procedure is basically the recovery of NH 4 F and uranium, as UF 4 , through the crystallization of ammonium bifluoride (NH 4 HF 2 ) and, in a later step, the addition of UO 2 , occurring fluoridation and decomposition. The UF 4 obtained is further diluted in the UF 4 produced routinely at IPEN / CNEN-SP by a wet route process. (author)

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

International Nuclear Information System (INIS)

Moore, R.H.; Kathren, R.L.

1985-01-01

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

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...

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.

Pilot plant UF6 to UF4 test operations report

International Nuclear Information System (INIS)

Bicha, W.J.; Fallings, M.; Gilbert, D.D.; Koch, G.E.; Levine, P.J.; McLaughlin, D.F.; Nuhfer, K.R.; Reese, J.C.

1987-02-01

The FMPC site includes a plant designed for the reduction of uranium hexafluoride (UF 6 ) to uranium tetrafluoride (UF 4 ). Limited operation of the upgraded reduction facility began in August 1984 and continued through January 19, 1986. A reaction vessel ruptured on that date causing the plant operation to be shut down. The DOE conducted a Class B investigation with the findings of the investigation board issued in preliminary form in May 1986 and as a final recommendation in July 1986. A two-phase restart of the plant was planned and implemented. Phase I included implementing safety system modifications, changing reaction vessel temperature control strategy, and operating the reduction plant under an 8-week controlled test. The results of the test period are the subject of this report. 41 figs., 11 tabs

Study of reactions for the obtention of uranium tetrafluoride and hexafluoride

International Nuclear Information System (INIS)

Guzella, M.F.R.

1984-01-01

Based on an exhaustive bibliographical review, the main production processes of uranium hexafluoride in pilot plants and industrial facilities are described. The known reactions, confirmed in laboratory experiments, that lead to UF 6 or other intermediate fluorides, are presented and discussed. In order to determine a new thermodinamically feasible reaction involving the sulfur hexafluoride as fluorinating agent, a mock-up facility was designed and constructed as part of the R and D work planned at CDTN (NUCLEBRAS Center for Nuclear Technology Development, MG - Brazil). For the UF 4 synthesis employing U 3 O 8 and SF 6 , several experimental parameters were studied. The reaction time, gas flow, temperature and stoichiometric relations among reagents are described in detail. Suggestions for further investigations regarding this new reagent are made. (Author) [pt

Stabilization of uranium hexafluoride by hydrolysis method for decommissioning of safeguard laboratory facility

Energy Technology Data Exchange (ETDEWEB)

Inagawa, Jun; Hotoku, Shinobu; Oda, Tetsuzo; Aoyagi, Noboru; Magara, Masaaki [Japan Atomic Energy Agency, Nuclear Science and Engineering Directorate, Tokai, Ibaraki (Japan)

2014-03-15

In safeguard laboratory (SGL) facility of Nuclear Science Research Institute of JAEA , uranium hexafluoride (UF{sub 6}) of enriched uranium of various enrichment was used for research and development of a spectrometric method for the determination of the enrichment of uranium in April 1983 through March 1993. After completion of this R and D, the UF{sub 6} has been stored in SGL facility. It was decided that the UF{sub 6} is carried to out of the facility, because the SGL facility will be decommissioning until March 2015. To transport and store in safety after transportation, it is necessary that the UF{sub 6} should be converted to stable chemical form. Hydrolysis of UF{sub 6} to uranyl fluoride (UO{sub 2}F{sub 2}) and evaporation to solid state were selected for the stabilization method. The equipment for hydrolysis and evaporation was installed in the SGL facility. Stabilization was operated in this equipment, and all of the UF{sub 6} in the SGL facility was converted to UO{sub 2}F{sub 2} solid state in October 2012 through August 2013. In this report, results of examination and operation for stabilization of UF{sub 6} were reported. (author)

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

International Nuclear Information System (INIS)

1995-01-01

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 (UF 6 ) 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 UF 6 handling procedures and reflects the policies of the USEC. This manual updates the material contained in earlier issues. It covers the essential aspects of UF 6 handling, cylinder filling and emptying, general principles of weighing and sampling, shipping, and the use of protective overpacks. The physical and chemical properties of UF 6 are also described. The procedures and systems described for safe handling of UF 6 presented in this document have been developed and evaluated during more than 40 years of handling vast quantities of UF 6 . With proper consideration for its nuclear properties, UF 6 may be safely handled in essentially the same manner as any other corrosive and/or toxic chemical

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

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

International Nuclear Information System (INIS)

Bacher, W.; Jacob, E.

1986-01-01

Uranium hexafluoride exhibits an unusual combination of properties: UF 6 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% 235 U as fuel in light water reactors. Enrichment is performed in isotope separation plants with UF 6 as the working gas. Its volatility and thermal stability make UF 6 suitable for this application. UF 6 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 UF 6 are characterized by its marked fluorination efficiency which is similar to that of F 2 . Of special importance in connection with the handling of UF 6 is its extreme sensitivity to hydrolysis. Because they all use UF 6 , 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 UF 6 decomposition products, e.g. by radiolysis of UF 6 molecules induced by its own radiation. Reconversion of UF 6 into UO 2 is achieved by three well-known methods (ADU, AUC, IDP-process). To produce uranium metal, UF 6 is first reduced to UF 4 , which is subsequently reduced by Ca 6 or Mg metal. 158 refs

Final programmatic environmental impact statement for alternative strategies for the long-term management and use of depleted uranium hexafluoride. Summary

International Nuclear Information System (INIS)

1999-04-01

This PEIS assesses the potential impacts of alternative management strategies for depleted uranium hexafluoride (UF 6 ) 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 UF 6 , 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 UF 6 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

Estimates of health risks associated with uranium hexafluoride transport by air

International Nuclear Information System (INIS)

Elert, M.; Skagius, K.

1990-01-01

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

Preliminary Hazard Analysis applied to Uranium Hexafluoride - UF6 production plant

International Nuclear Information System (INIS)

Tomzhinsky, David; Bichmacher, Ricardo; Braganca Junior, Alvaro; Peixoto, Orpet Jose

1996-01-01

The purpose of this paper is to present the results of the Preliminary hazard Analysis applied to the UF 6 Production Process, which is part of the UF 6 Conversion Plant. The Conversion Plant has designed to produce a high purified UF 6 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)

UF{sub 6} cylinder lifting equipment enhancements

Energy Technology Data Exchange (ETDEWEB)

Hortel, J.M. [Martin Marietta Energy Systems, Inc., Piketon, OH (United States)

1991-12-31

This paper presents numerous enhancements that have been made to the Portsmouth lifting equipment to ensure the safe handling of cylinders containing liquid uranium hexafluoride (UF{sub 6}). The basic approach has been to provide redundancy to all components of the lift path so that any one component failure would not cause the load to drop or cause any undesirable movement.

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

International Nuclear Information System (INIS)

Silva Neto, Joao Batista da

2008-01-01

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 UF 6 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 NH 4 HF 2 precipitation. Working with the solid residues, the crystallized bifluoride is added to the solid UO 2 , which comes from the U mini plates recovery, also to its conversion in a solid state reaction, to obtain UF 4 . That returns to the process of metallic uranium production unity to the U 3 Si 2 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 U 3 Si 2 -Al fuel. (author)

Criticality concerns in cleaning large uranium hexafluoride cylinders

International Nuclear Information System (INIS)

Sheaffer, M.K.; Keeton, S.C.; Lutz, H.F.

1995-06-01

Cleaning large cylinders used to transport low-enriched uranium hexafluoride (UF 6 ) presents several challenges to nuclear criticality safety. This paper presents a brief overview of the cleaning process, the criticality controls typically employed and their bases. Potential shortfalls in implementing these controls are highlighted, and a simple example to illustrate the difficulties in complying with the Double Contingency Principle is discussed. Finally, a summary of recommended criticality controls for large cylinder cleaning operations is presented

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

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-01-01

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 (UF{sub 6}) 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 UF{sub 6} handling procedures and reflects the policies of the USEC. This manual updates the material contained in earlier issues. It covers the essential aspects of UF{sub 6} handling, cylinder filling and emptying, general principles of weighing and sampling, shipping, and the use of protective overpacks. The physical and chemical properties of UF{sub 6} are also described. The procedures and systems described for safe handling of UF{sub 6} presented in this document have been developed and evaluated during more than 40 years of handling vast quantities of UF{sub 6}. With proper consideration for its nuclear properties, UF{sub 6} may be safely handled in essentially the same manner as any other corrosive and/or toxic chemical.

Scoping study to expedite development of a field deployable and portable instrument for UF6 enrichment assay

OpenAIRE

Chan, CYG; Valentine, JD; Russo, RE

2017-01-01

The primary objective of the present study is to identity the most promising, viable technologies that are likely to culminate in an expedited development of the next-generation, field-deployable instrument for providing rapid, accurate, and precise enrichment assay of uranium hexafluoride (UF6). UF6 is typically involved, and is arguably the most important uranium compound, in uranium enrichment processes. As the first line of defense against proliferation, accurate analytical techniques t...

Process for decontamination of surfaces in an facility of natural uranium hexafluoride production (UF{sub 6}); Processo de descontaminação de superfícies em uma instalação de produção de hexafluoreto de urânio natural (UF{sub 6})

Energy Technology Data Exchange (ETDEWEB)

Almeida, Claudio C. de; Silva, Teresinha M.; Rodrigues, Demerval L.; Carneiro, Janete C.G.G., E-mail: calmeida@ipen.br [Instituto de Pesquisas Energéticas e Nucleares(IPEN/CNEN-SP), São Paulo, SP (Brazil). Gerência de Radioproteção

2017-07-01

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

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)

1997-12-01

This PEIS assesses the potential impacts of alternative management of alternative management strategies for depleted uranium hexafluoride (UF 6 ) 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 UF 6 , 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 UF 6 is to use the entire inventory of material

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

International Nuclear Information System (INIS)

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

1999-01-01

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

Cost-effectiveness of safety measures applying to uranium hexafluoride transportation in France

International Nuclear Information System (INIS)

Hubert, P.; Pages, P.; Auguin, B.

1983-01-01

This paper addresses the problem of uranium hexafluoride transportation by truck and train. It consists of a probabilistic risk assessment of the potential hazards to the public that can arise from the traffice that will take place in France in 1990. The specificity of UF 6 is that it presents both chemical and radiological hazards. But, whatever the transported material, road traffic entails a risk of its own. Thus three kinds of risk are assessed for natural, depleted and enriched uranium hexafluoride. These assessments are the basis of a cost-effectiveness analysis which deals with such safety measures as using a protective overpack, avoiding populated area and escorting the trucks. The results presented here are based upon research supported by the C.E.A. (Commissariat a l'Energie Atomique). It is linked to a more general program of experiments and theoretical analyses on package safety and accidental releases for uranium hexafluoride. 7 references, 2 figures, 4 tables

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

International Nuclear Information System (INIS)

Becker, D.L.; Green, D.J.; Lindquist, M.R.

1993-07-01

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 uranium hexafluoride (UF 6 ). Uranium hexafluoride enriched uranium than 1.0 wt percent 235 U 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 UF 6 cylinders/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 UF 6 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 is documented in Reference 4

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)

1997-12-01

This PEIS assesses the potential impacts of alternative management of alternative management strategies for depleted uranium hexafluoride (UF 6 ) 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 UF 6 , 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 UF 6 is to use the entire inventory of material. This volume contains the appendices to volume I

Selection of a management strategy for depleted uranium hexafluoride

International Nuclear Information System (INIS)

Patton, S.E.; Hanrahan, E.J.; Bradley, C.E.

1995-01-01

A consequence of the uranium enrichment process used in the United States (US) is the accumulation of a significant amount of depleted uranium hexafluoride (UF 6 ). 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 UF 6 . 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

A review of laser isotope separation of uranium hexafluoride

International Nuclear Information System (INIS)

Kelly, J.W.

1983-04-01

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 UF 6 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

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)

1999-04-01

This PEIS assesses the potential impacts of alternative management strategies for depleted uranium hexafluoride (UF 6 ) 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 UF 6 , 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 UF 6 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

Infrared analysis of hydrogen fluoride in uranium hexafluoride

International Nuclear Information System (INIS)

Ohwada, Ken; Soga, Takeshi; Iwasaki, Matae; Tsujimura, Shigeo

1975-01-01

Quantitative analysis by infrared technique was made on hydrogen fluoride (HF) contained in uranium hexafluoride (UF 6 ). It was found that, among the vibration-rotation bands, the R(1)-, R(2)-, P(2)- and P(3)-branches having relatively large absorbances are convenient for the analysis of HF. Upon comparing the calibration curves of pure HF with the HF absorbances observed in the presence of UF 6 (approx. 70--100 Torr), N 2 (approx. 100 Torr) and Ar(approx. 100 Torr) gases, it was observed that the first-mentioned calibration curve could be applied to the analysis of HF when mixed with other substances, as in the latter cases. The detectable limits of HF pressure, using a infrared cell of 10cm path length, were 0.5--1 Torr at room temperature. (auth.)

Study of the molecular structure of uranium hexafluoride; Contribution a l'etude de la structure moleculaire de l'hexafluorure d'uranium

Energy Technology Data Exchange (ETDEWEB)

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

1967-06-01

The vibrational spectrum of uranium hexafluoride has been studied in both the gaseous and solid states. The study of gaseous UF{sub 6} 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 UF{sub 6}; this distortion has only observed up till now by means of X-ray diffraction and nuclear magnetic resonance techniques. (author) [French] Le spectre de vibration de l'hexafluorure d'uranium UF{sub 6} est etudie sous les formes gazeuse et solide. L'etude de l'UF{sub 6} gaz confirme la structure d'octaedre regulier d'atomes de fluor autour de l'atome central d'uranium et apporte une precision sur certaines frequences de vibration. A partir de ces valeurs, de nouvelles determinations de constantes de force ont ete realisees. L'observation de UF{sub 6} solide confirme la deformation tetragonale de l'octaedre, deformation observee jusqu'a present par les seules methodes de resonance magnetique nucleaire et diffraction des rayons X. (auteur)

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)

1999-04-01

This PEIS assesses the potential impacts of alternative management strategies for depleted uranium hexafluoride (UF 6 ) 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 UF 6 , 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 UF 6 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

Development of AN Active 238UF6 Gas Target

Science.gov (United States)

Eckardt, C.; Enders, J.; Freudenberger, M.; Göök, A.; von Neumann-Cosel, P.; Oberstedt, A.; Oberstedt, S.

2014-09-01

Detailed studies of the fission process, e.g., the search for parity nonconservation (PNC) effects, the energy dependence of fission modes or the population of fission isomers, depend on high quality data, therefore requiring high luminosities. An active gas target containing uranium may overcome the deterioration of energy and angular resolution caused by large solid target thicknesses. A single Frisch-grid ionization chamber has been built to test a mixture of standard counting gases (e.g., argon) with depleted uranium hexafluoride (238UF6), utilizing a triple alpha source to evaluate signal quality and drift velocity. For mass fractions of up to 4 percent of 238U the drift velocity increases with rising UF6 content, while a good signal quality and energy resolution is preserved.

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...

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.

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...

Metamorphosis: Phases of UF{sub 6}

Energy Technology Data Exchange (ETDEWEB)

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

1991-12-31

A 15-minute videotape is presented. The subject matter is 150 grams of UF{sub 6} sealed in a glass tube. Close-up views show the UF{sub 6} as phase changes are effected by the addition or removal of heat from the closed system. The solid-to-liquid transition is shown as heat is added, both slowly and rapidly. The solid phases which result from freezing and from desublimation are contrasted. In the solid state, uranium hexafluoride is a nearly-white, dense crystalline solid. The appearance of this solid depends on whether it is formed by freezing from the liquid or by desublimation from the vapor phase. If frozen from the liquid, the solid particles take the form of irregularly shaped coarse grains, while the solid product of desublimation tends to be a rather formless mass without individually distinguishable particles. The changes in state are presented in terms of the UF{sub 6} phase diagram.

Method and apparatus for measuring enrichment of UF6

Science.gov (United States)

Hill, Thomas Roy [Santa Fe, NM; Ianakiev, Kiril Dimitrov [Los Alamos, NM

2011-06-07

A system and method are disclosed for determining the enrichment of .sup.235U in Uranium Hexafluoride (UF6) utilizing synthesized X-rays which are directed at a container test zone containing a sample of UF6. A detector placed behind the container test zone then detects and counts the X-rays which pass through the container and the UF6. In order to determine the portion of the attenuation due to the UF6 gas alone, this count rate may then be compared to a calibration count rate of X-rays passing through a calibration test zone which contains a vacuum, the test zone having experienced substantially similar environmental conditions as the actual test zone. Alternatively, X-rays of two differing energy levels may be alternately directed at the container, where either the container or the UF6 has a high sensitivity to the difference in the energy levels, and the other having a low sensitivity.

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.

Interim guidance on the safe transport of uranium hexafluoride

International Nuclear Information System (INIS)

1991-06-01

Uranium hexafluoride (UF 6 ) is a radioactive material that has significant non-radiological hazardous properties. In conformity with international regulatory practice for dangerous goods transport, these properties are classed as ''subsidiary risks'', although they predominate in the cases of depleted and natural UF 6 . UF 6 is transported as a solid material below atmospheric pressure. The IAEA Regulations for the Safe Transport of Radioactive Material, 1985 Edition, Safety Series No. 6, make recommendations that aimed to provide an adequate level of safety against radiological and criticality hazards. The basis for these is that the stringency of package performance requirements, operational procedures and approval and administrative procedures is graded relative to the severity of the hazard. The cylinders used for transporting UF 6 are also used in the production, storage and use of the material and that the fraction of their life cycle in which transport is involved is small. Consideration must also be given to the large number of existing cylinders (estimated to be between 60,000 and 70,000). Specific recommendations provided for UF 6 transport, listed in Section II, are additional to the requirements of the Regulations. The intent of these additional recommendations is to restrict contamination and to provide protection to workers and to the general public against the chemical hazard possibly resulting from a severe accident involving the transport of UF 6 , and in addition against the consequences of explosive rupture of small bare cylinders of UF 6 . 20 refs, figs and tabs

Uranium hexafluoride: A manual of good handling practices

International Nuclear Information System (INIS)

1991-10-01

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 (UF 6 ) shipping containers and handling procedures. The information contained in this manual updates information contained in earlier issues. It covers the essential aspects of UF 6 handling, cylinder filling and emptying, general principles of weighing and sampling, shipping, and the use of protective overpacks. The physical and chemical properties of UF 6 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 UF 6 cylinders, samples, and overpacks. The quality of feed materials is important to the safe and efficient operation of the enriching facilities, and the UF 6 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 UF 6 presented in this document have been developed and evaluated in DOE facilities during more than 40 years of handling vast quantities of UF 6 . With proper consideration for its nuclear properties, UF 6 may be safely handled in essentially the same manner as any other corrosive and/or toxic chemical

Radiation dose rates from UF{sub 6} cylinders

Energy Technology Data Exchange (ETDEWEB)

Friend, P.J. [Urenco, Capenhurst (United Kingdom)

1991-12-31

This paper describes the results of many studies, both theoretical and experimental, which have been carried out by Urenco over the last 15 years into radiation dose rates from uranium hexafluoride (UF{sub 6}) cylinders. The contents of the cylinder, its history, and the geometry all affect the radiation dose rate. These factors are all examined in detail. Actual and predicted dose rates are compared with levels permitted by IAEA transport regulations.

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.

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

International Nuclear Information System (INIS)

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

1998-01-01

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 2 ) and uranium hexafluoride (UF 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 2 and UF 6 to the charcoal bed were the possibility of explosive reactions between the charcoal and F 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 2 -UF 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

Uranium isotope exchange between gaseous UF6 and solid UF5

International Nuclear Information System (INIS)

Yato, Yumio; Kishimoto, Yoichiro; Sasao, Nobuyuki; Suto, Osamu; Funasaka, Hideyuki

1996-01-01

Based on a collision model, a new rate equation is derived for uranium isotope exchange between gaseous UF 6 and solid UF 5 by considering the number of UF 5 molecules on the solid surface to be dependent on time. The reaction parameters included in the equation are determined from the experimental data and compared with the previous ones. A remarkable agreement is found between the particle sizes of UF 5 estimated from the reaction parameter and from the direct observation with an electron microscope. The rate equation given in this work fully satisfies the related mass conservation and furthermore includes explicitly the terms related to the UF 6 density and the mean size of UF 5 particles, both of which are considered to cause an important effect on the reaction. This remarkable feature facilitates the simulation studies on this reaction under various conditions. The long term behavior of a simulated exchange reaction is studied under the condition considered to be close to that in a recovery zone of the MLIS process. The result indicates that the reaction is virtually limited to the solid surface under this conditions and thus the depletion of 235 UF 5 concentration averaged over the whole UF 5 particles is not significant even after 200 h of the exchange reaction

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

International Nuclear Information System (INIS)

Becker, D.L.; Lindquist, M.R.

1993-01-01

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 (UF 6 ). Uranium hexafluoride enriched greater than 1.0 wt percent 235 U 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 UF 6 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 UF 6 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

Preparation of sodium fluoride agglomerates for selective adsorption of uranium hexafluoride (U F6)

International Nuclear Information System (INIS)

Castro, A.R.; Maximiano, C.; Shimba, R.; Silva, E.R.F.

1995-01-01

Uranium hexafluoride (U F 6 ) and Sodium Fluoride (NaF) reacts reversibly to form a solid complex. Such reversibility accounts for the great interest in using Sodium Fluoride (NaF) to separate Uranium Hexafluoride (U F 6 ) from other gases. Therefore a chemical trap offers an alternative to the cryogenic trapping device. (author). 3 refs, 1 fig, 4 tabs

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)

Almeida, Claudio C. de; Cambises, Paulo B.S.; Paiva, Julio E. de; Paiva, Julio E. de; Silva, Teresina M.; Rodrigues, Demerval L.

2013-01-01

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

Evaluation of a RF-Based Approach for Tracking UF6 Cylinders at a Uranium Enrichment Plant

International Nuclear Information System (INIS)

Pickett, Chris A; Younkin, James R; Kovacic, Donald N; Laughter, Mark D; Hines, Jairus B; Boyer, Brian Martinez

2008-01-01

Approved industry-standard cylinders are used globally to handle and store uranium hexafluoride (UF 6 ) feed, product, tails, and samples at uranium enrichment plants. The International Atomic Energy Agency (IAEA) relies on time-consuming physical inspections to verify operator declarations and detect possible diversion of UF 6 . Development of a reliable, automated, and tamper-resistant system for near real-time tracking and monitoring UF 6 cylinders (as they move within an enrichment facility) would greatly improve the inspector function. This type of system can reduce the risk of false or misreported cylinder tare weights, diversion of nuclear material, concealment of excess production, utilization of undeclared cylinders, and misrepresentation of the cylinders contents. This paper will describe a proof-of-concept approach that was designed to evaluate the feasibility of using radio frequency (RF)-based technologies to track individual UF 6 cylinders throughout a portion of their life cycle, and thus demonstrate the potential for improved domestic accountability of materials, and a more effective and efficient method for application of site-level IAEA safeguards. The evaluation system incorporates RF-based identification devices (RFID) which provide a foundation for establishing a reliable, automated, and near real-time tracking system that can be set up to utilize site-specific, rules-based detection algorithms. This paper will report results from a proof-of-concept demonstration at a real enrichment facility that is specifically designed to evaluate both the feasibility of using RF to track cylinders and the durability of the RF equipment to survive the rigors of operational processing and handling. The paper also discusses methods for securely attaching RF devices and describes how the technology can effectively be layered with other safeguard systems and approaches to build a robust system for detecting cylinder diversion. Additionally, concepts for off

Qualification for Safeguards Purposes of UF6 Sampling using Alumina – Results of the Evaluation Campaign of ABACC-Cristallini Method

OpenAIRE

ESTAEBAN ADOLFO; GAUTIER EDUARDO; MACHADO DA SILVA LUIS; FERNANDEZ MORENO SONIA; RENHA JR GERALDO; DIAS FABIO; PEREIRA DE OLIVEIRA JUNIOR OLIVIO; AMMARAGGI DAVID; MASON PETER; SORIANO MICHAEL; CROATTO PAUL; ZULEGER EVELYN; GIAQUINTO JOSEPH; HEXEL COLE; VERCOUTER THOMAS

2017-01-01

The procedure currently used to sample material from process lines in uranium enrichment plants consists of collecting the uranium hexafluoride (UF6) in gaseous phase by desublimation inside a metal sampling cylinder cooled with liquid nitrogen or in certain facilities in a fluorothene P-10 tube type. The ABACC-Cristallini method (A-C method) has been proposed to collect the UF6 (gas) by adsorption in alumina (Al2O3) in the form of uranyl fluoride (UO2F2) (solid). This method uses a fluor...

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

International Nuclear Information System (INIS)

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 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 6 and 14,600 MT of enriched UF 6 would be shipped in the reference year

Determination of the isotopic ratio 235U/238U in UF6 using quadrupole mass spectrometry

International Nuclear Information System (INIS)

Kusahara, Helena Sueco

1979-01-01

In this work measurements of isotope ratios 235 U / 23 '8U in uranium hexafluoride are carried out using a quadrupole mass spectrometer. The operational parameters, which affect the final precision of the results, are standardized. Optimized procedures for the preparation of uranium hexafluoride samples by fluorination of uranium oxides using cobalt trifluoride method are established. Careful attention is given to the process of purification of uranium hexafluoride samples by fractional distillation. Adequate statistical methods for analysing the results obtained for single ratio measurements as well as the ratio ' of isotopic ratios of sample and standard ar.e developed. A precision of about 10 -4 for single ratio measurements and accuracy of about 0,3% for the ratio of sample and standard ratios are obtained. These results agree with the values which have been obtained using magnetic mass spectrometers. The procedures and methods established in this work can be employed in the systematic uranium isotope analysis in UF 6 form. (author)

Metabolic fate and evaluation of injury in rats and dogs following exposure to the hydrolysis products of uranium hexafluoride: implications for a bioassay program related to potential releases of uranium hexafluoride, July 1979-October 1981

International Nuclear Information System (INIS)

Morrow, P.E.; Leach, L.J.; Smith, F.A.

1982-12-01

This final report summarizes the experimental studies undertaken in rats and dogs in order to help provide adequate biological bases for quantifying and evaluating uranium hexafluoride (UF 6 ) exposures. Animals were administered the hydrolysis products of UF 6 by inhalation exposures, intratracheal instillations and intravenous injections. Attention was given to dose-effect relationships appropriate to the kidney, the unique site of subacute toxicity; to the rates of uranium excretion; and to uranium retention in renal tissue. These criteria were examined in both naive and multiply-exposed animals. The findings of these studies partly substantiate the ICRP excretion model for hexavalent uranium; generally provide a lower renal injury threshold concentration than implicit in the MPC for natural uranium; indicate distinctions in response (for example, uranium excretion) are based on exposure history; compare and evaluate various biochemical indices of renal injury; raise uncertainties about prevailing views of reversible renal injury, renal tolerance and possible hydrogen fluoride synergism with uranium effects; and reveal species differences in several areas, for example, renal retention of uranium. While these studies present some complicating features to extant bioassay practice, they nevertheless supply data supportive of the bioassay concept

Ultra-low field NMR for detection and characterization of 235 UF6

Energy Technology Data Exchange (ETDEWEB)

Espy, Michelle A [Los Alamos National Laboratory; Magnelind, Per E [Los Alamos National Laboratory; Matlashov, Andrei N [Los Alamos National Laboratory; Urbaitis, Algis V [Los Alamos National Laboratory; Volegov, Petr L [Los Alamos National Laboratory

2009-01-01

We have demonstrated the first ultra-low field (ULF) nuclear magnetic resonance measurements of uranium hexafluoride (UF{sub 6}), both depleted and 70% enriched, which is used in the uranium enrichment process. A sensitive non-invasive detection system would have an important role in non-proliferation surveillance. A two-frequency technique was employed to remove the transients induced by rapidly switching off the 50 mT pre-polarization field. A mean transverse relaxation time T{sub 2} of 24 ms was estimated for the un-enriched UF{sub 6} sample measured at a mean temperature of 80 C. Nuclear magnetic resonance at ULF has several advantages including the ability to measure through metal, such as pipes, and simple magnetic field generation hardware. We present here recent data and discuss the potential for non-proliferation monitoring of enrichment and flow velocity.

Analyses of postulated accidental releases of UF6 inside process buildings

International Nuclear Information System (INIS)

Oliveira Neto, Jose Messias de; Nunes, Beatriz Guimaraes; Dias, Cristiane

2009-01-01

Uranium Hexafluoride is a material used in the various processes which comprise the front end of the nuclear fuel cycle (conversion, enrichment and fuel fabrication). Confinement of UF 6 is a very important safety requirement since this material is highly reactive and presents safety hazards to humans. The present paper discusses the safety relevant aspects of accidental releases of UF 6 inside process confinement buildings. Postulated accidental scenarios are analyzed and their consequences evaluated. Implant releases rates are estimated using computer code predictions. A time dependent homogeneous compartment model is used to predict concentrations of UF 6 , hydrogen fluoride and uranyl fluoride inside a confinement building, as well as to evaluate source terms released to the atmosphere. These source terms can be used as input to atmospheric dispersion models to evaluate consequences to the environment. The results can also be used to define adequate protective measures for emergency situations. (author)

Investigation of the UF6 aerosol behavior in air, (4)

International Nuclear Information System (INIS)

Ishida, Junichiro; Sakamoto, Genji; Takeda, Seiichi; Kato, Jinzo

1979-01-01

When gaseous uranium hexafluoride (UF 6 ) is released into air, it hydrolizes with moisture in air to produce HF gas and particulate UO 2 F 2 which is visible. The lowest visible concentration in air is about 5 x 10 -8 μCi/cm 3 in case of releasing UF 6 and about 10 -9 μCi/cm 3 in case of released UF 6 cloud. By watching the occurrence of released UF 6 cloud, it is possible to take necessary action without delay. But in the case that there is no one to watch or that the concentration is not high enough to be visible, an alarm monitor system has to be relied on. Therefore the characteristics of the alarm monitors which can detect UF 6 promptly were examined. As UF 6 is hydrolized into gaseous HF and particulate UO 2 F 2 , three monitoring methods are considered; (1) to detect the alpha radiation of uranium, (2) to detect HF gas and (3) to detect airborne particles (aerosol). Performance tests were conducted on an alpha dust monitor, an electrochemical HF monitor, a thin film electrolyte HF monitor and an ionized smoke detector. The relationship between radioactivity concentration and HF concentration was investigated especially regarding with the conditions of released UF 6 amount and the distance from a release point to the observation point. The experimental facilities containing a large glove-box made of SUS and acrylic resin walls, a dust monitor, an HF monitor, a smoke detector and a filter, and the experimental procedure are explained. As the experimental results, the response characteristics of the dust monitor and HF monitor, the relationship of radioactivity concentration to HF concentration in air and the relation of the distance from the release point to the concentration of U and HF are presented. (Nakai, Y.)

Chemisorption of uranium hexa-fluoride on sodium fluoride pellets

Energy Technology Data Exchange (ETDEWEB)

Kalburgi, A K; Sanyal, A; Puranik, V D; Bhattacharjee, B [Chemical Technology Division, Bhabha Atomic Research Centre, Mumbai (India)

1994-06-01

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 UF{sub 6} 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 UF{sub 6} on NaF pellets. The kinetic equation for the above process has been established for a particular size of NaF pellets and pellet porosity. (author). 5 refs., 3 figs., 3 tabs.

Standard test method for determination of bromine and chlorine in UF6 and uranyl nitrate by X-Ray fluorescence (XRF) spectroscopy

CERN Document Server

American Society for Testing and Materials. Philadelphia

2001-01-01

1.1 This method covers the determination of bromine (Br) and chlorine (Cl) in uranium hexafluoride (UF6) and uranyl nitrate solution. The method as written covers the determination of bromine in UF6 over the concentration range of 0.2 to 8 μg/g, uranium basis. The chlorine in UF6 can be determined over the range of 4 to 160 μg/g, uranium basis. Higher concentrations may be covered by appropriate dilutions. The detection limit for Br is 0.2 μg/g uranium basis and for Cl is 4 μg/g uranium basis. 1.2 This standard may involve hazardous materials, operations and equipment. 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.

Electrically Cooled Germanium System for Measurements of Uranium Enrichments in UF6 Cylinders

International Nuclear Information System (INIS)

Dvornyak, P.; Koestlbauer, M.; Lebrun, A.; Murray, M.; Nizhnik, V.; Saidler, C.; Twomey, T.

2010-01-01

Measurements of Uranium enrichment in UF6 cylinders is a significant part of the IAEA Safeguards verification activities at enrichment and conversion plants. Nowadays, one of the main tools for verification of Uranium enrichment in UF6 cylinders used by Safeguards inspectors is the gamma spectroscopy system with HPGe detector cooled with liquid nitrogen. Electrically Cooled Germanium System (ECGS) is a new compact and portable high resolution gamma spectrometric system free from liquid nitrogen cooling, which can be used for the same safeguards applications. It consists of the ORTEC Micro-trans-SPEC HPGe Portable Spectrometer, a special tungsten collimator and UF6 enrichment measurement software. The enrichment of uranium is determined by of quantifying the area of the 185.7 keV peak provided that the measurement is performed with a detector viewing an infinite thickness of material. Prior starting the verification of uranium enrichment at the facility, the ECGS has to be calibrated with a sample of known uranium enrichment, material matrix, container wall thickness and container material. Evaluation of the ECGS capabilities was performed by carrying out a field test on actual enrichment verification of uranium in UF6 cylinder or other forms of uranium under infinite thickness conditions. The results of these evaluations allow to say that the use of ECGS will enhance practicality of the enrichment measurements and support unannounced inspection activities at enrichment and conversion plants. (author)

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...

Collect method of uranium hexafluoride

International Nuclear Information System (INIS)

Moura, S.C.; Bustillos, O.W.V.

1991-01-01

A collect method of uranium hexafluoride was designed, constructed and assembled in Analytical Laboratory from Instituto de Energia Atomica, Sao Paulo, Brazil. This method of collect is main for quality control of uranium hexafluoride. (author)

New approach for safeguarding enriched uranium hexafluoride bulk transfers

International Nuclear Information System (INIS)

Doeher, L.W.; Pontius, P.E.; Whetstone, J.R.

1978-01-01

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 (UF 6 ) 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 UF 6 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 UF 6 mass measurement process. A recent demonstration, which exchanged UF 6 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

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

International Nuclear Information System (INIS)

Huffer, J.E.

1997-04-01

This paper determines the nuclear safety of gaseous UF 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 6 in plant operations

Uranium price reporting systems

International Nuclear Information System (INIS)

1987-09-01

This report describes the systems for uranium price reporting currently available to the uranium industry. The report restricts itself to prices for U 3 O 8 natural uranium concentrates. Most purchases of natural uranium by utilities, and sales by producers, are conducted in this form. The bulk of uranium in electricity generation is enriched before use, and is converted to uranium hexafluoride, UF 6 , prior to enrichment. Some uranium is traded as UF 6 or as enriched uranium, particularly in the 'secondary' market. Prices for UF 6 and enriched uranium are not considered directly in this report. However, where transactions in UF 6 influence the reported price of U 3 O 8 this influence is taken into account. Unless otherwise indicated, the terms uranium and natural uranium used here refer exclusively to U 3 O 8 . (author)

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

International Nuclear Information System (INIS)

Pope, R.B.; Cash, J.M.; Singletary, B.H.

1996-01-01

There is a need to develop a means of safely transporting breached 48-in. cylinders containing depleted uranium hexafluoride (UF 6 ) 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 UF 6 . 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

Cracked lifting lug welds on ten-ton UF{sub 6} cylinders

Energy Technology Data Exchange (ETDEWEB)

Dorning, R.E. [Martin Marietta Energy Systems, Inc., Piketon, OH (United States)

1991-12-31

Ten-ton, Type 48X, UF{sub 6} cylinders are used at the Portsmouth Gaseous Diffusion Plant to withdraw enriched uranium hexafluoride from the cascade, transfer enriched uranium hexafluoride to customer cylinders, and feed enriched product to the cascade. To accomplish these activities, the cylinders are lifted by cranes and straddle carriers which engage the cylinder lifting lugs. In August of 1988, weld cracks on two lifting lugs were discovered during preparation to lift a cylinder. The cylinder was rejected and tagged out, and an investigating committee formed to determine the cause of cracking and recommend remedial actions. Further investigation revealed the problem may be general to this class of cylinder in this use cycle. This paper discusses the actions taken at the Portsmouth site to deal with the cracked lifting lug weld problem. The actions include inspection activities, interim corrective actions, metallurgical evaluation of cracked welds, weld repairs, and current monitoring/inspection program.

Long-term evaluation of fluoroelastomer O-rings in UF6

International Nuclear Information System (INIS)

Russell, R.G.; Otey, M.G.; Dippo, G.L.

1986-01-01

A major component in the gaseous centrifuge enrichment plant (GCEP) was fluoroelastomer O-rings, which were used to seal the uranium hexafluoride (UF 6 ) gas system. A program utilizing accelerated test conditions was used to help identify the best material out of four selected candidates and to predict the service life of these materials at GCEP conditions. The tests included accelerated temperatures, mechanical stress, and UF 6 exposure. Data were evaluated using the Newman--Keuls 1 ranking system to identify the best material and a zero-order reaction rate equation to help predict service life. This presentation includes a description of the test facility, the materials tested, the types of tests, objectives of the study, service life predictions, and conclusions. The O-rings are predicted to last approx. 30 years, and a high-molecular-weight polymer had the best performance ranking

Aspects of uranium chemistry pertaining to UF{sub 6} cylinder handling

Energy Technology Data Exchange (ETDEWEB)

Ritter, R.L.; Barber, E.J. [Martin Marietta Energy Systems, Inc., Oak Ridge, TN (United States)

1991-12-31

Under normal conditions, the bulk of UF{sub 6} in storage cylinders will be in the solid state with an overpressure of gaseous UF{sub 6} well below one atmosphere. Corrosion of the interior of the cylinder will be very slow, with formation of a small amount of reduced fluoride, probably U{sub 2}F{sub 9}. The UO{sub 3}-HF-H{sub 2}O phase diagram indicates that reaction of any inleaking water vapor with the solid UF{sub 6} will generate the solid material [H{sub 3}O]{sub 2}(U(OH){sub 4}F{sub 4}) in equilibrium with an aqueous HF solution containing only small amounts of uranium. The corrosion of the steel cylinder by these materials may be enhanced over that observed with gaseous anhydrous UF{sub 6}.

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)

Electron affinity of UF6. Final report, March 1, 1976--June 30, 1977

International Nuclear Information System (INIS)

Rothe, E.W.

1977-06-01

Ionization reactions are observed in crossed molecular beams, usually of thermal energy, alkalis and MoF 6 , WF 6 and UF 6 . Previous studies have indicated large electron affinities for these hexafluorides, and this is confirmed here. Ionization at thermal energies proceeds with the alkali dimers, A 2 , for all three hexafluorides, but with alkali atoms, A, only for UF 6 . Several ionization paths are observed, allowing the deduction of molecular energies. A few experiments are done with eV-range beams. Lower limits for the elecron affinities are 4.5, 3.3, 4.9, 4.3 and 1.9 eV for MoF 6 , MoF 5 , WF 6 , UF 6 and UF 5 , respectively. Possible mechanisms are discussed

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)

1999-04-01

This PEIS assesses the potential impacts of alternative management strategies for depleted uranium hexafluoride (UF 6 ) 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 UF 6 , 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 UF 6 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

Developments of solid materials for UF₆ sampling

Energy Technology Data Exchange (ETDEWEB)

Smith, Nicholas [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Hebden, Andrew [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Savina, Joseph [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division

2017-11-15

This project demonstrated that a device using majority Commercial Off the Shelf (COTS) components could be used to collect uranium hexafluoride samples safely from gaseous or solid sources. The device was based on the successful Cristallini method developed by ABACC over the past 10 years. The system was designed to capture and store the UF₆ as an inert fluoride salt to ease transportation regulations. In addition, the method was considerably faster than traditional cryogenic methods, collected enough material to perform analyses without undue waste, and could be used either inside a facility or in the storage yard.

Production of sized particles of uranium oxides and uranium oxyfluorides

International Nuclear Information System (INIS)

Knudsen, I.E.; Randall, C.C.

1976-01-01

A process is claimed for converting uranium hexafluoride (UF 6 ) to uranium dioxide (UO 2 ) 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

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..

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)

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

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.

Cost-effectiveness of safety measures to reduce public risk associated with the transportation of UF6 by truck and trains

International Nuclear Information System (INIS)

Hubert, Philippe; Pages, Pierre

1989-01-01

The present case study deals with the problem of uranium hexafluoride transportation by truck and train. It consists of a probabilistic risk assessment of the potential hazards to the public that can arise from the traffic that will take place in France in 1990. The specificity of UF 6 is that it presents both chemical and radiological hazards. But, whatever the transported material, road traffic entails a risk of its own. Thus three kinds of risks are assessed for natural, depleted and enriched uranium hexafluoride. These assessments are the basis of a cost-effectiveness analysis which deals with such safety measures as using a protective overpack, avoiding populated areas and escorting the trucks

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...

Correlation of radioactive waste treatment costs and the environmental impact of waste effluents in the nuclear fuel cycle: conversion of recycle uranium to UF6

International Nuclear Information System (INIS)

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

1977-04-01

A cost/benefit study was made to determine the cost and effectiveness of various radioactive waste (radwaste) treatment systems for decreasing the amount of radioactive materials released from a model recycle uranium conversion and uranium hexafluoride (UF 6 ) production plant and to determine the radiological impact (dose commitment) of the released radioactive materials on the environment. This study is designed to assist the US NRC in defining the term ''as low as reasonably achievable'' as it applies to these nuclear facilities. The base case model plant is representative of a licensable UF 6 production plant and has an annual capacity of 1500 metric tons of uranium. Additional radwaste treatment systems are added 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 cost for the added waste treatment operations and the corresponding dose commitments is 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. The methodology used in estimating the costs is presented

Cost-effectiveness of safety measures to reduce public risk associated with the transportation of UF{sub 6} by truck and trains

Energy Technology Data Exchange (ETDEWEB)

Hubert, Philippe; Pages, Pierre

1989-08-01

The present case study deals with the problem of uranium hexafluoride transportation by truck and train. It consists of a probabilistic risk assessment of the potential hazards to the public that can arise from the traffic that will take place in France in 1990. The specificity of UF{sub 6} is that it presents both chemical and radiological hazards. But, whatever the transported material, road traffic entails a risk of its own. Thus three kinds of risks are assessed for natural, depleted and enriched uranium hexafluoride. These assessments are the basis of a cost-effectiveness analysis which deals with such safety measures as using a protective overpack, avoiding populated areas and escorting the trucks.

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

International Nuclear Information System (INIS)

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 4 is used as the sensitizer to absorb energy from a pulsed CO 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 6 is the reactant, CF 3 Cl is used as reagent to trap atomic fluorine reaction product, forming CF 4 as a stable indicator which is easily detected by infrared spectroscopy. Using these techniques, we estimate the UF 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 6 as a function of temperature and gas composition and total pressure. 85 refs., 17 figs., 14 tabs

Transport of UF6 in compliance with TS-R-1

International Nuclear Information System (INIS)

Dekker, B.G.

2004-01-01

The IAEA Regulations TS-R-1 (ST-1, Revised) 1996 Edition include requirements for packages containing uranium hexafluoride (UF6); these are the first and only substance-specific requirements in the IAEA regulations. These requirements have already particularly affected, and will further affect, the transport of non-fissile and fissile excepted UF 6 and the packages used for these transports. Non-fissile and fissile excepted UF6 (ASTM C 787) has been transported worldwide for decades in a safe and reliable manner, using internationally standardised packages. Under the auspices of the World Nuclear Transport Institute (WNTI), an industry working group has been evaluating the existing packages against the requirements in TS-R-1. As new requirements came into effect, there were new challenges for the use of these standard packages, including the free drop test and the thermal requirements. In close cooperation with the WNTI HEXT Industry Working Group, a consortium of UF6 producers/users has worked together on the design and development, testing and certification of technical solutions for modification and optimisation of the existing packages to comply with TS-R-1. This paper reviews the existing standard packages against the requirements in TS-R-1. An update is also given describing the enhancements to the standard packages that have been designed and developed recently. The paper also describes how these solutions have been tested and certified, as well as the status of implementation. Finally, a review is made of the options that are available internationally to transport UF6 in compliance with TS-R-1. (author)

Technology Assessment for Proof-of-Concept UF6 Cylinder Unique Identification Task 3.1.2 Report – Survey and Assessment of Technologies

Energy Technology Data Exchange (ETDEWEB)

Wylie, Joann; Hockert, John

2014-04-24

The National Nuclear Security Administration (NNSA) Office of Nonproliferation and International Security’s (NA-24) Next Generation Safeguards Initiative (NGSI) and the nuclear industry have begun to develop approaches to identify and monitor uranium hexafluoride (UF6) cylinders. The NA-24 interest in a global monitoring system for UF6 cylinders relates to its interest in supporting the International Atomic Energy Agency (IAEA) in deterring and detecting diversion of UF6 (e.g., loss of cylinder in transit) and undeclared excess production at conversion and enrichment facilities. The industry interest in a global monitoring system for UF6 cylinders relates to the improvements in operational efficiencies that such a system would provide. This task is part of an effort to survey and assess technologies for a UF6 cylinder to identify candidate technologies for a proof-of-concept demonstration and evaluation for the Cylinder Identification System (CIS).

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.

Calculations of electronic structure of UF6 molecule and crystal UO2 with relativistic pseudopotential

International Nuclear Information System (INIS)

Ehvarestov, R.A.; Panin, A.I.; Bandura, A.V.

2008-01-01

Account of relativistic effects on the properties of uranium hexafluoride is testified. Detailed comparison of single electron energies spectrum revealed in nonrelativistic (by Hartree-Fock method), relativistic (by Dirac-Fock method), and scalar-relativistic (using relativistic potential of atomic uranium frame) has been conducted. Optimization procedures of atomic basis in LCAO calculations of molecules and crystals permissive taking into account distortion of atomic orbitals when chemical bonding are discussed, and optimization effect of atomic basis on the results of scalar-relativistic calculations of UF 6 molecule properties is analyzed. Calculations of electronic structure and properties of UO 2 crystal having relativistic and nonrelativistic pseudopotentials have been realized [ru

Process for producing uranium oxide rich compositions from uranium hexafluoride

International Nuclear Information System (INIS)

DeHollander, W.R.; Fenimore, C.P.

1978-01-01

Conversion of gaseous uranium hexafluoride to a uranium dioxide rich composition in the presence of an active flame in a reactor defining a reaction zone is achieved by separately introducing a first gaseous reactant comprising a mixture of uranium hexafluoride and a reducing carrier gas, and a second gaseous reactant comprising an oxygen-containing gas. The reactants are separated by a shielding gas as they are introduced to the reaction zone. The shielding gas temporarily separates the gaseous reactants and temporarily prevents substantial mixing and reacting of the gaseous reactants. The flame occurring in the reaction zone is maintained away from contact with the inlet introducing the mixture to the reaction zone. After suitable treatment, the uranium dioxide rich composition is capable of being fabricated into bodies of desired configuration for loading into nuclear fuel rods. Alternatively, an oxygen-containing gas as a third gaseous reactant is introduced when the uranium hexafluoride conversion to the uranium dioxide rich composition is substantially complete. This results in oxidizing the uranium dioxide rich composition to a higher oxide of uranium with conversion of any residual reducing gas to its oxidized form

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

International Nuclear Information System (INIS)

Fisher, D.R.; Swint, M.J.; Kathren, R.L.

1990-05-01

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 (UF 6 ) 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

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

Energy Technology Data Exchange (ETDEWEB)

Fisher, D.R. (Pacific Northwest Lab., Richland, WA (USA)); Swint, M.J.; Kathren, R.L. (Hanford Environmental Health Foundation, Richland, WA (USA))

1990-05-01

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 (UF{sub 6}) 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.

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

International Nuclear Information System (INIS)

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

1997-06-01

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

Distribution of uranium supply and enrichment

International Nuclear Information System (INIS)

Bamford, F.W.

1982-01-01

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

Release of UF6 from a ruptured model 48Y cylinder at Sequoyah Fuels Corporation Facility: lessons-learned report

International Nuclear Information System (INIS)

1986-08-01

The uranium hexafluoride (UF 6 ) release of January 4, 1986, at the Sequoyah Fuels Corporation facility has been reviewed by a NRC Lessons-Learned Group. A Model 48Y cylinder containing UF 6 ruptured upon being heated after it was grossly overfilled. The UF 6 released upon rupture of the cylinder reacted with airborne moisture to produce hydrofluoric acid (HF) and uranyl fluoride (UO 2 F 2 ). One individual died from exposure to airborne HF and several others were injured. There were no significant immediate effects from exposure to uranyl fluoride. This supplement report contains NRC's response to the recommendations made in NUREG-1198 by the Lessons Learned Group. In developing a response to each of the recommendations, the staff considered actions that should be taken: (1) for the restart of the Sequoyah Fuels Facility; (2) to make near-term improvement; and (3) to improve the regulatory framework

Analysis of an indirect neutron signature for enhanced UF_6 cylinder verification

International Nuclear Information System (INIS)

Kulisek, J.A.; McDonald, B.S.; Smith, L.E.; Zalavadia, M.A.; Webster, J.B.

2017-01-01

The International Atomic Energy Agency (IAEA) currently uses handheld gamma-ray spectrometers combined with ultrasonic wall-thickness gauges to verify the declared enrichment of uranium hexafluoride (UF_6) cylinders. The current method provides relatively low accuracy for the assay of "2"3"5U enrichment, especially for natural and depleted UF_6. Furthermore, the current method provides no capability to assay the absolute mass of "2"3"5U in the cylinder due to the localized instrument geometry and limited penetration of the 186-keV gamma-ray signature from "2"3"5U. Also, the current verification process is a time-consuming component of on-site inspections at uranium enrichment plants. Toward the goal of a more-capable cylinder assay method, the Pacific Northwest National Laboratory has developed the hybrid enrichment verification array (HEVA). HEVA measures both the traditional 186-keV direct signature and a non-traditional, high-energy neutron-induced signature (HEVA_N_T). HEVA_N_T enables full-volume assay of UF_6 cylinders by exploiting the relatively larger mean free paths of the neutrons emitted from the UF_6. In this work, Monte Carlo modeling is used as the basis for characterizing HEVA_N_T in terms of the individual contributions to HEVA_N_T from nuclides and hardware components. Monte Carlo modeling is also used to quantify the intrinsic efficiency of HEVA for neutron detection in a cylinder-assay geometry. Modeling predictions are validated against neutron-induced gamma-ray spectra from laboratory measurements and a relatively large population of Type 30B cylinders spanning a range of enrichments. Implications of the analysis and findings on the viability of HEVA for cylinder verification are discussed, such as the resistance of the HEVA_N_T signature to manipulation by the nearby placement of neutron-conversion materials.

The IAEA recommendations for providing protection during the transport of uranium hexafluoride

International Nuclear Information System (INIS)

Levin, I.; Wieser, K.

1988-01-01

The Regulations for the safe transport of radioactive materials, are the basis of national and international regulations concerning this subject throughout the world. These regulations require that subsidiary hazards associated with radioactive materials should also be considered. Other national and international regulations concerning the transport of dangerous materials consider that a radioactive material having other dangerous properties should be classified as class 7. Following this line and acting upon the recommendations of SAGSTRAM (Standing Advisory Committee on the Safe Transport of Radioactive Materials) that the Agency should take the lead in providing guidance to Member States with respect to UF 6 packaging and transport, the Agency convened two expert meetings during 1986 and 1987 in order to look into the special problems associated with the transport of uranium hexafluoride. The experts identified several areas in which additional safety measures should be considered if the transport of UF 6 is to have a non-radiological safety level consistent with that of its radiological risks. In this presentation the new recommendations are described. The main safety issues to be discussed are fire resistance, valve protection and compatibility with service and structural equipment. Another aspect of importance is the interface between the process and the transport phases, bearing in mind that the same containers are used in both. This paper also reveals how far the new recommendations concerning UF 6 have already been endorsed in the forthcoming European Transport Regulations (ADR/RID) together with the 1985 revised Edition of IAEA Safety Series No. 6

The multiphoton ionization of uranium hexafluoride

International Nuclear Information System (INIS)

Armstrong, D.P.

1992-05-01

Multiphoton ionization (MPI) time-of-flight mass spectroscopy and photoelectron spectroscopy studies of UF 6 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 UF x + fragment ions even at the lowest laser power densities at which signal could be detected. The laser power dependence of U n+ ions signals indicates that saturation can occur for many of the steps required for their ionization. In general, the doubly-charged uranium ion (U 2+ ) intensity is much greater than that of the singly-charged uranium ion (U + ). For the case of the tunable dye laser experiments, the U n+ (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 U 2+ ion and the absence or very small intensities of UF x + 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

Dry uranium tetrafluoride process preparation using the uranium hexafluoride reconversion process effluents; Processo alternativo para obtencao de tetrafluoreto de uranio a partir de efluentes fluoretados da etapa de reconversao de uranio

Energy Technology Data Exchange (ETDEWEB)

Silva Neto, Joao Batista da

2008-07-01

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 UF{sub 6} 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 NH{sub 4}HF{sub 2} precipitation. Working with the solid residues, the crystallized bifluoride is added to the solid UO{sub 2}, which comes from the U mini plates recovery, also to its conversion in a solid state reaction, to obtain UF{sub 4}. That returns to the process of metallic uranium production unity to the U{sub 3}Si{sub 2} 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 U{sub 3}Si{sub 2}-Al fuel. (author)

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

International Nuclear Information System (INIS)

1975-02-01

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

Argon/UF6 plasma exhaust gas reconstitution experiments using preheated fluorine and on-line diagnostics. [fissioning uranium plasma core reactor design

Science.gov (United States)

Roman, W. C.

1979-01-01

The feasibility of employing a flowing, high-temperature, pure fluorine/UF6 regeneration system to efficiently convert a large fraction of the effluent plasma exhaust back to pure UF6 was demonstrated. The custom built T.O.F. mass spectrometer sampling system permitted on-line measurements of the UF6 concentration at different locations in the exhaust system. Negligible amounts ( 100 ppm) of UF6 were detected in the axial bypass exhaust duct and the exhaust ducts downstream of the cryogenic trap system used to collect the UF6, thus verifying the overall system efficiency over a range of operating conditions. Use of a porous Monel duct as part of the exhaust duct system, including provision for injection of pure fluorine, provided a viable technique to eliminate uranium compound residue on the inside surface of the exhaust ducts. Typical uranium compound mass deposition per unit area of duct was 2 micron g/sq cm. This porous duct technique is directly applicable to future uranium compound transfer exhaust systems. Throughout these experiments, additional basic data on the corrosion aspects of hot, pressurized UF6/fluorine were also accumulated.

Modeling and analyses of postulated UF6 release accidents in gaseous diffusion plant

International Nuclear Information System (INIS)

Kim, S.H.; Taleyarkhan, R.P.; Keith, K.D.; Schmidt, R.W.; Carter, J.C.; Dyer, R.H.

1995-10-01

Computer models have been developed to simulate the transient behavior of aerosols and vapors as a result of a postulated accident involving the release of uranium hexafluoride (UF 6 ) into the process building of a gaseous diffusion plant. UF 6 undergoes an exothermic chemical reaction with moisture (H 2 O) in the air to form hydrogen fluoride (HF) and radioactive uranyl fluoride (UO 2 F 2 ). As part of a facility-wide safety evaluation, this study evaluated source terms consisting of UO 2 F 2 as well as HF during a postulated UF 6 release accident in a process building. In the postulated accident scenario, ∼7900 kg (17,500 lb) of hot UF 6 vapor is released over a 5 min period from the process piping into the atmosphere of a large process building. UO 2 F 2 mainly remains as airborne-solid particles (aerosols), and HF is in a vapor form. Some UO 2 F 2 aerosols are removed from the air flow due to gravitational settling. The HF and the remaining UO 2 F 2 are mixed with air and exhausted through the building ventilation system. The MELCOR computer code was selected for simulating aerosols and vapor transport in the process building. MELCOR model was first used to develop a single volume representation of a process building and its results were compared with those from past lumped parameter models specifically developed for studying UF 6 release accidents. Preliminary results indicate that MELCOR predicted results (using a lumped formulation) are comparable with those from previously developed models

Analysis of enriched HF-UF6 systems. Influence by impurity and density upon the value of the multiplication

International Nuclear Information System (INIS)

Acosta, N.B.; Canavese, S.I.; Lopez, M.L.

1990-01-01

The purpose of this paper is analyzing the influence of impurity in hydrogen fluoride and in density variation (UF 6 -HF) upon the value of the effective multiplication factor (Kef) in enriched uranium hexafluoride and hydrogen fluoride systems. The identification of the values of such multiplication factors were performed by means of the Monte-Carlo (MONK V.II) code, which is specific for criticality problems. Diverse systems were considered by keeping the same geometry and varying the density value and the impurity percentages, while the assumptions made for each model were described on a case-by-case basis. Also, systems with and without water infinite reflector were evaluated. Finally, an analysis is made of the influence of each parameter upon the effective multiplication factor, in the postulated enriched UF 6 -HF systems. (Author) [es

Review of models used for determining consequences of UF6 release: Development of model evaluation criteria. Volume 1

International Nuclear Information System (INIS)

Nair, S.K.; Chambers, D.B.; Park, S.H.; Hoffman, F.O.

1997-11-01

The objective of this study is to examine the usefulness and effectiveness of currently existing models that simulate the release of uranium hexafluoride from UF 6 -handling facilities, subsequent reactions of UF 6 with atmospheric moisture, and the dispersion of UF 6 and reaction products in the atmosphere. The study evaluates screening-level and detailed public-domain models that were specifically developed for UF 6 and models that were originally developed for the treatment of dense gases but are applicable to UF 6 release, reaction, and dispersion. The model evaluation process is divided into three specific tasks: model-component evaluation; applicability evaluation; and user interface and quality assurance and quality control (QA/QC) evaluation. Within the model-component evaluation process, a model's treatment of source term, thermodynamics, and atmospheric dispersion are considered and model predictions are compared with actual observations. Within the applicability evaluation process, a model's applicability to Integrated Safety Analysis, Emergency Response Planning, and Post-Accident Analysis, and to site-specific considerations are assessed. Finally, within the user interface and QA/QC evaluation process, a model's user-friendliness, presence and clarity of documentation, ease of use, etc. are assessed, along with its handling of QA/QC. This document presents the complete methodology used in the evaluation process

Criticality safety concerns of uranium deposits in cascade equipment

International Nuclear Information System (INIS)

Plaster, M.J.

1996-01-01

The Paducah and Portsmouth Gaseous Diffusion Plants enrich uranium in the 235 U isotope by diffusing gaseous uranium hexafluoride (UF 6 ) through a porous barrier. The UF 6 gaseous diffusion cascade utilized several thousand open-quotes stagesclose quotes of barrier to produce highly enriched uranium (HEU). Historically, Portsmouth has enriched the Paducah Gaseous Diffusion Plant's product (typically 1.8 wt% 235 U) as well as natural enrichment feed stock up to 97 wt%. Due to the chemical reactivity of UF 6 , particularly with water, the formation of solid uranium deposits occur at a gaseous diffusion plant. Much of the equipment operates below atmospheric pressure, and deposits are formed when atmospheric air enters the cascade. Deposits may also be formed from UF 6 reactions with oil, UF 6 reactions with the metallic surfaces of equipment, and desublimation of UF 6 . The major deposits form as a result of moist air in leakage due to failure of compressor casing flanges, blow-off plates, seals, expansion joint convolutions, and instrument lines. This report describes criticality concerns and deposit disposition

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....420 Uranium hexafluoride (fissile, fissile excepted and non-fissile). (a) In addition to any other... non-fissile uranium hexafluoride must be offered for transportation as follows: (1) Before initial...

Analysis of an indirect neutron signature for enhanced UF{sub 6} cylinder verification

Energy Technology Data Exchange (ETDEWEB)

Kulisek, J.A., E-mail: Jonathan.Kulisek@pnnl.gov; McDonald, B.S.; Smith, L.E.; Zalavadia, M.A.; Webster, J.B.

2017-02-21

The International Atomic Energy Agency (IAEA) currently uses handheld gamma-ray spectrometers combined with ultrasonic wall-thickness gauges to verify the declared enrichment of uranium hexafluoride (UF{sub 6}) cylinders. The current method provides relatively low accuracy for the assay of {sup 235}U enrichment, especially for natural and depleted UF{sub 6}. Furthermore, the current method provides no capability to assay the absolute mass of {sup 235}U in the cylinder due to the localized instrument geometry and limited penetration of the 186-keV gamma-ray signature from {sup 235}U. Also, the current verification process is a time-consuming component of on-site inspections at uranium enrichment plants. Toward the goal of a more-capable cylinder assay method, the Pacific Northwest National Laboratory has developed the hybrid enrichment verification array (HEVA). HEVA measures both the traditional 186-keV direct signature and a non-traditional, high-energy neutron-induced signature (HEVA{sub NT}). HEVA{sub NT} enables full-volume assay of UF{sub 6} cylinders by exploiting the relatively larger mean free paths of the neutrons emitted from the UF{sub 6}. In this work, Monte Carlo modeling is used as the basis for characterizing HEVA{sub NT} in terms of the individual contributions to HEVA{sub NT} from nuclides and hardware components. Monte Carlo modeling is also used to quantify the intrinsic efficiency of HEVA for neutron detection in a cylinder-assay geometry. Modeling predictions are validated against neutron-induced gamma-ray spectra from laboratory measurements and a relatively large population of Type 30B cylinders spanning a range of enrichments. Implications of the analysis and findings on the viability of HEVA for cylinder verification are discussed, such as the resistance of the HEVA{sub NT} signature to manipulation by the nearby placement of neutron-conversion materials.

Joint ANSI-INMM 8.1: Nuclear Regulatory Commission study of uranium hexafluoride cylinder material accountability bulk measurements

International Nuclear Information System (INIS)

Pontius, P.E.; Doher, L.W.

1977-01-01

This paper reports the progress to date in a demonstration of the procedures in ANSI N15.18-1975, ''Mass Calibration Techniques for Nuclear Material Control,'' sponsored and funded by the Nuclear Regulatory Commission (NRC). The philosophy of mass measurement as a production process, as promulgated in ANSI N15.18-1975, is reviewed. Special emphasis is placed on the use of artifact Reference Mass Standards (RMS) as references for uranium hexafluoride (UF 6 ) calibration and bulk measurement processes. The history of the creation of the artifact concept and its adoption by ANSI N15.18-1975 and the Nuclear Regulatory Commission is narrated. The program now under way is specifically described; including descriptions of the RMS, their calibration, and the assignment of uncertainties to them by the National Bureau of Standards (NBS). Instrument tests, in-house standards (IHS), and assignment of values relative to the RMS-NBS values at nuclear facilities which measure UF 6 cylinders are described. Comparisons and the data base are detailed to provide realistic measurement process parameters associated with accountable transfer of UF 6 . The as yet uncompleted part of the demonstration is described, that is, to further close the measurement loop by verification both between and within facilities

Seismic design of a uranium conversion plant building

International Nuclear Information System (INIS)

Peixoto, O.J.M.; Botelho, C.L.A.; Braganca, A. Jr.; C. Santos, S.H. de.

1992-01-01

The design of facilities with small radioactive inventory has been traditionally performed following the usual criteria for industrial buildings. In the last few years, more stringent criteria have been adopted in new nuclear facilities in order to achieve higher standards for environmental protection. In uranium conversion plants, the UF 6 (uranium hexafluoride) production step is the part of the process with the highest potential for radioactivity release to the environment because of the operations performed in the UF 6 desublimers and cylinder filling areas as well as UF 6 distillation facilities, when they are also required in the process. This paper presents the design guidelines and some details of the seismic resistance design of a UF 6 production building to be constructed in Brazil

Uranium hexafluoride. Bromine spectrophotometric determination

International Nuclear Information System (INIS)

Anon.

Bromine determination in hydrolized uranium hexafluoride by reduction of bromates by ferrous sulfate, oxidation of bromides by potassium permanganate to give bromine which is extracted into carbon tetrachloride and transformed in eosine for spectrophotometry at 510 nm. The method is suitable for determining 5 to 150 ppm with respect to uranium [fr

Uranium hexafluoride production plant decommissioning

International Nuclear Information System (INIS)

Santos, Ivan

2008-01-01

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 (UF 6 ) 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)

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

International Nuclear Information System (INIS)

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

2008-01-01

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

Investigation of technology for monitoring UF6 mass flow

International Nuclear Information System (INIS)

Cooley, J.N.; Moran, B.W.; Swindle, D.W. Jr.

1987-06-01

The applicability of gas flow meters, in-line enrichment monitors, and instruments for measuring uranium or UF 6 concentrations in process streams as a means for verifying declared plant throughput have been investigated. The study was performed to assist the International Atomic Energy Agency in the development of an effective international safeguards approach for aerodynamic uranium enrichment plants. Because the process gas in an aerodynamic enrichment facility is a mixture of UF 6 and H 2 , a mass flow measurement in conjunction with a measurement of the uranium (or UF 6 ) concentration in the process gas is required to quantify the amount of uranium being fed into, and withdrawn from, the cascades for nuclear materials accountability verification. In-line enrichment monitors developed for the US gas centrifuge enrichment plant are found to be applicable only to pure UF 6 streams. Of the five gas flow meters evaluated, the orifice meter and the pitot tube meter are judged the best choices for the proposed applications: the first is recommended for low-velocity gas, small diameter piping; the latter, for high-velocity gas, large diameter piping. Of the six procedures evaluated for measurement of uranium or UF 6 concentration in a mixed process stream, infrared-ultraviolet-visible spectrophotometry is judged to be the best procedure currently available to perform the required measurement. 4 refs., 3 figs., 3 tabs

Next Generation Safeguards Initiative: Overview and Policy Context of UF6 Cylinder Tracking Program

Energy Technology Data Exchange (ETDEWEB)

Boyer, Brian D [Los Alamos National Laboratory; Whitaker, J. Michael [ORNL; White-Horton, Jessica L. [ORNL; Durbin, Karyn R. [NNSA

2012-07-12

Thousands of cylinders containing uranium hexafluoride (UF{sub 6}) move around the world from conversion plants to enrichment plants to fuel fabrication plants, and their contents could be very useful to a country intent on diverting uranium for clandestine use. Each of these large cylinders can contain close to a significant quantity of natural uranium (48Y cylinder) or low-enriched uranium (LEU) (30B cylinder) defined as 75 kg {sup 235}U which can be further clandestinely enriched to produce 1.5 to 2 significant quantities of high enriched uranium (HEU) within weeks or months depending on the scale of the clandestine facility. The National Nuclear Security Administration (NNSA) Next Generation Safeguards Initiative (NGSI) kicked off a 5-year plan in April 2011 to investigate the concept of a unique identification system for UF{sub 6} cylinders and potentially to develop a cylinder tracking system that could be used by facility operators and the International Atomic Energy Agency (IAEA). The goal is to design an integrated solution beneficial to both industry and inspectorates that would improve cylinder operations at the facilities and provide enhanced capabilities to deter and detect both diversion of low-enriched uranium and undeclared enriched uranium production. The 5-year plan consists of six separate incremental tasks: (1) define the problem and establish the requirements for a unique identification (UID) and monitoring system; (2) develop a concept of operations for the identification and monitoring system; (3) determine cylinder monitoring devices and technology; (4) develop a registry database to support proof-of-concept demonstration; (5) integrate that system for the demonstration; and (6) demonstrate proof-of-concept. Throughout NNSA's performance of the tasks outlined in this program, the multi-laboratory team emphasizes that extensive engagement with industry stakeholders, regulatory authorities and inspectorates is essential to its success.

Decommissioning of an uranium hexafluoride pilot plant

International Nuclear Information System (INIS)

Santos, Ivan; Abrao, Alcidio; Carvalho, Fatima M.S.; Ayoub, Jamil M.S.

2009-01-01

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)

Review of models used for determining consequences of UF6 release: Model evaluation report. Volume 2

International Nuclear Information System (INIS)

Nair, S.K.; Chambers, D.B.; Park, S.H.; Radonjic, Z.R.; Coutts, P.T.; Lewis, C.J.; Hammonds, J.S.; Hoffman, F.O.

1997-11-01

Three uranium hexafluoride-(UF 6 -) specific models--HGSYSTEM/UF 6 , Science Application International Corporation, and RTM-96; three dense-gas models--DEGADIS, SLAB, and the Chlorine Institute methodology; and one toxic chemical model--AFTOX--are evaluated on their capabilities to simulate the chemical reactions, thermodynamics, and atmospheric dispersion of UF 6 released from accidents at nuclear fuel-cycle facilities, to support Integrated Safety Analysis, Emergency Response Planning, and Post-Accident Analysis. These models are also evaluated for user-friendliness and for quality assurance and quality control features, to ensure the validity and credibility of the results. Model performance evaluations are conducted for the three UF 6 -specific models, using field data on releases of UF 6 and other heavy gases. Predictions from the HGSYSTEM/UF 6 and SAIC models are within an order of magnitude of the field data, but the SAIC model overpredicts beyond an order of magnitude for a few UF 6 -specific data points. The RTM-96 model provides overpredictions within a factor of 3 for all data points beyond 400 m from the source. For one data set, however, the RTM-96 model severely underpredicts the observations within 200 m of the source. Outputs of the models are most sensitive to the meteorological parameters at large distances from the source and to certain source-specific and meteorological parameters at distances close to the source. Specific recommendations are being made to improve the applicability and usefulness of the three models and to choose a specific model to support the intended analyses. Guidance is also provided on the choice of input parameters for initial dilution, building wake effects, and distance to completion of UF 6 reaction with water

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

International Nuclear Information System (INIS)

1995-01-01

This report describes the Conversion and Blending Facility (CBF) which will have two missions: (1) convert surplus HEU materials to pure HEU UF 6 and a (2) blend the pure HEU UF 6 with diluent UF 6 to produce LWR grade LEU-UF 6 . 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

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

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-07-05

This report describes the Conversion and Blending Facility (CBF) which will have two missions: (1) convert surplus HEU materials to pure HEU UF{sub 6} and a (2) blend the pure HEU UF{sub 6} with diluent UF{sub 6} to produce LWR grade LEU-UF{sub 6}. 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.

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

International Nuclear Information System (INIS)

Stitt, D.H.

1978-01-01

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 UF 6 , under the assumed worst case impact orientation

Releases of UF6 to the atmosphere after a potential fire in a cylinder storage yard

International Nuclear Information System (INIS)

Lombardi, D.A.; Williams, W.R.; Anderson, J.C.

1997-01-01

Uranium hexafluoride (UF 6 ), a toxic material, is stored in just over 6200 cylinders at the K-25 site in Oak Ridge, Tennessee. The safety analysis report (SAR) for cylinder yard storage operations at the plant required the development of accident scenarios for the potential release of UF 6 to the atmosphere. In accordance with DOE standards and guidance, the general approach taken in this SAR was to examine the functions and contents of the cylinder storage yards to determine whether safety-significant hazards were present for workers in the immediate vicinity, workers on-site, the general public off-site, or the environment. and to evaluate the significance of any hazards that were found. A detailed accident analysis was performed to determine a set of limiting accidents that have potential for off-site consequences. One of the limiting accidents identified in the SAR was the rupture of a cylinder engulfed in a fire

Scoping study to expedite development of a field deployable and portable instrument for UF6 enrichment assay

Energy Technology Data Exchange (ETDEWEB)

Chan, George; Valentine, John D.; Russo, Richard E.

2017-09-14

The primary objective of the present study is to identity the most promising, viable technologies that are likely to culminate in an expedited development of the next-generation, field-deployable instrument for providing rapid, accurate, and precise enrichment assay of uranium hexafluoride (UF6). UF6 is typically involved, and is arguably the most important uranium compound, in uranium enrichment processes. As the first line of defense against proliferation, accurate analytical techniques to determine the uranium isotopic distribution in UF6 are critical for materials verification, accounting, and safeguards at enrichment plants. As nuclear fuel cycle technology becomes more prevalent around the world, international nuclear safeguards and interest in UF6 enrichment assay has been growing. At present, laboratory-based mass spectrometry (MS), which offers the highest attainable analytical accuracy and precision, is the technique of choice for the analysis of stable and long-lived isotopes. Currently, the International Atomic Energy Agency (IAEA) monitors the production of enriched UF6 at declared facilities by collecting a small amount (between 1 to 10 g) of gaseous UF6 into a sample bottle, which is then shipped under chain of custody to a central laboratory (IAEA’s Nuclear Materials Analysis Laboratory) for high-precision isotopic assay by MS. The logistics are cumbersome and new shipping regulations are making it more difficult to transport UF6. Furthermore, the analysis is costly, and results are not available for some time after sample collection. Hence, the IAEA is challenged to develop effective safeguards approaches at enrichment plants. In-field isotopic analysis of UF6 has the potential to substantially reduce the time, logistics and expense of sample handling. However, current laboratory-based MS techniques require too much infrastructure and operator expertise for field deployment and operation. As outlined in the IAEA Department of Safeguards Long

Uranium conversion

International Nuclear Information System (INIS)

Oliver, Lena; Peterson, Jenny; Wilhelmsen, Katarina

2006-03-01

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

Review of models used for determining consequences of UF{sub 6} release: Model evaluation report. Volume 2

Energy Technology Data Exchange (ETDEWEB)

Nair, S.K.; Chambers, D.B.; Park, S.H.; Radonjic, Z.R.; Coutts, P.T.; Lewis, C.J.; Hammonds, J.S.; Hoffman, F.O. [Senes Oak Ridge, Inc., TN (United States). Center for Risk Analysis

1997-11-01

Three uranium hexafluoride-(UF{sub 6}-) specific models--HGSYSTEM/UF{sub 6}, Science Application International Corporation, and RTM-96; three dense-gas models--DEGADIS, SLAB, and the Chlorine Institute methodology; and one toxic chemical model--AFTOX--are evaluated on their capabilities to simulate the chemical reactions, thermodynamics, and atmospheric dispersion of UF{sub 6} released from accidents at nuclear fuel-cycle facilities, to support Integrated Safety Analysis, Emergency Response Planning, and Post-Accident Analysis. These models are also evaluated for user-friendliness and for quality assurance and quality control features, to ensure the validity and credibility of the results. Model performance evaluations are conducted for the three UF{sub 6}-specific models, using field data on releases of UF{sub 6} and other heavy gases. Predictions from the HGSYSTEM/UF{sub 6} and SAIC models are within an order of magnitude of the field data, but the SAIC model overpredicts beyond an order of magnitude for a few UF{sub 6}-specific data points. The RTM-96 model provides overpredictions within a factor of 3 for all data points beyond 400 m from the source. For one data set, however, the RTM-96 model severely underpredicts the observations within 200 m of the source. Outputs of the models are most sensitive to the meteorological parameters at large distances from the source and to certain source-specific and meteorological parameters at distances close to the source. Specific recommendations are being made to improve the applicability and usefulness of the three models and to choose a specific model to support the intended analyses. Guidance is also provided on the choice of input parameters for initial dilution, building wake effects, and distance to completion of UF{sub 6} reaction with water.

Potential detection systems for monitoring UF6 releases

International Nuclear Information System (INIS)

Beck, D.E.; Bostick, W.D.; Armstrong, D.P.; McNeely, J.R.; Stockdale, J.A.D.

1994-09-01

In the near future, the Nuclear Regulatory Commission (NRC) will begin to regulate the gaseous diffusion plants. Them is a concern that the smoke detectors currently used for uranium hexafluoride (UF 6 ) release detection will not meet NRC safety system requirements such as high reliability and rapid response. The NRC's position is that licensees should utilize state-of-the-art equipment such as hydrogen fluoride (HF) detectors that would provide more dependable detection of a UF 6 release. A survey of the literature and current vendor information was undertaken to define the state-of-the-art and commercial availability of HF (or other appropriate) detection systems. For the purpose of this report, classification of the available HF detection systems is made on the basis of detection principle (e.g., calorimetric, electrochemical, separational, or optical). Emphasis is also placed on whether the device is primarily sensitive to response from a point source (e.g., outleakage in the immediate vicinity of a specific set of components), or whether the device is potentially applicable to remote sensing over a larger area. Traditional HF point source monitoring typically uses gas sampling tubes or coated paper tapes with color developing indicator, portable and small area HF monitors are often based upon electrochemical or extractive/separational systems; and remote sensing by optical systems holds promise for indoor and outdoor large area monitoring (including plant boundary/ambient air monitoring)

Purification process of uranium hexafluoride containing traces of plutonium fluoride and/or neptunium fluoride

International Nuclear Information System (INIS)

Aubert, J.; Bethuel, L.; Carles, M.

1983-01-01

In this process impure uranium hexafluoride is contacted with a metallic fluoride chosen in the group containing lead fluoride PbF 2 , uranium fluorides UFsub(4+x) (0 3 at a temperature such as plutonium and/or neptunium are reduced and pure uranium hexafluoride is recovered. Application is made to uranium hexafluoride purification in spent fuel reprocessing [fr

Uranium conversion; Urankonvertering

Energy Technology Data Exchange (ETDEWEB)

Oliver, Lena; Peterson, Jenny; Wilhelmsen, Katarina [Swedish Defence Research Agency (FOI), Stockholm (Sweden)

2006-03-15

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

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

International Nuclear Information System (INIS)

Barlow, C.R.; Alderson, J.H.; Blue, S.C.; Boelens, R.A.; Conkel, M.E.; Dorning, R.E.; Ecklund, C.D.; Halicks, W.G.; Henson, H.M.; Newman, V.S.; Philpot, H.E.; Taylor, M.S.; Vournazos, J.P.; Pryor, W.A.; Ziehlke, K.T.

1992-07-01

Isotopically depleted UF 6 (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 UF 6 . 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

Analytical standards for accountability of uranium hexafluoride - 1972

International Nuclear Information System (INIS)

Anon.

1976-01-01

An analytical standard for the accountability of uranium hexafluoride is presented that includes procedures for subsampling, determination of uranium, determination of metallic impurities and isotopic analysis by gas and thermal ionization mass spectrometry

The uncertainty evaluation of measurement for uranium in UF_6 hydrolysate by potentiometric titration

International Nuclear Information System (INIS)

Jiang Haiying; Cheng Ruoyu; Meng Xiujun

2014-01-01

Based on the building of mathematical model, this paper analyzed the origin of component of indeterminacy of which the measurement result for uranium in uranium hexafluoride hydrolysate by potentiometric titration, also each uncertainty was calculated and the expanded uncertainty was given. By evaluation the result of the uranium concentration is that: (158.88 + 1.22) mgU/mL, K = 2, P = 95%. (authors)

Uranium isotope fractionation resulting from UF6 vapor distillation from containers

International Nuclear Information System (INIS)

Hedge, W.D.; Turner, C.M.

1985-01-01

This empirical study for possible isotopic fractionation due to UF 6 vapor distillation from valved containers was performed to determine the effects of repeated vapor sampling. Four different experiments were performed, each of which varied by the method of measuring the isotopic contents and/or by the difference in temperature gradients as follows: The ratio of the parent UF 6 to the desublimed UF 6 collected at liquid nitrogen temperature and homogenized was measured by sampling the containers. The ratio of the parent UF 6 to the desublimed UF 6 collected at liquid nitrogen temperature and homogenized was measured by direct comparison to each other without subsampling. The ratio of the parent UF 6 to the desublimed UF 6 collected at liquid nitrogen and ice-water temperatures and homogenized was measured by indirect comparison to a common UF 6 reference material without subsampling. The ratio of the parent UF 6 to the desublimed UF 6 collected at liquid nitrogen temperature without homogenizing was measured by indirect comparison to a common UF 6 reference. Gas-phase, relative mass spectrometry was used for all isotopic measurements. Results of the study indicate that fractionation does occur. The U-235 isotope becomes more enriched in the parent container as the UF 6 is vaporized from it and desublimed into the receiving cylinder; i.e., the vaporized fraction is enriched in the U-238 isotope. The degree of fractionation indicates that the separation is due to the U-238 isotope of UF 6 having a higher vapor pressure than the U-235 isotope of UF 6 . 3 refs., 4 figs., 4 tabs

Similarity of dependences of thermal conductivity and density of uranium and tungsten hexafluorides on desublimation conditions

International Nuclear Information System (INIS)

Barkov, V.A.

1989-01-01

Consideration is given to results of investigations of the dependence of thermal conductivity and density of UF 6 and WF 6 desublimates on volume content of hexafluoride in initial gaseous mixture. Similarity of these dependences, as well as the dependences of thermal conductivity of desublimates on their density was revealed. Generalized expressions, relating thermal conductivity and density of desublimates among each ofter and with volume content of hexafluoride in gaseous mixture were derived. Possibility of applying the generalized relations for calculation of thermal conductivity and density of other compounds of MeF 6 type under prescribed desublimation conclitions is shown. 15 refs.; 6 figs

Release of UF6 from a ruptured Model 48Y cylinder at Sequoyah Fuels Corporation Facility: lessons-learned report

International Nuclear Information System (INIS)

1986-06-01

The uranium hexafluoride (UF 6 ) release of January 4, 1986, at the Sequoyah Fuels Corporation facility has been reviewed by a NRC Lessons-Learned Group. A Model 48Y cylinder containing UF 6 ruptured upon being heated after it was grossly overfilled. The Uf 6 released upon rupture of the cylinder reacted with airborne moisture to produce hydrofluoric acid (HF) and uranyl fluoride (UO 2 F 2 ). One individual died from exposure to airborne HF and several others were injured. There were no significant immediate effects from exposure to uranyl fluoride. This report of the Lessons-Learned Group presents discussions and recommendations on the process, operation and design of the facility, as well as on the responses of the licensee, NRC, and other local, state and federal agencies to the incident. It also provides recommendations in the areas of NRC licensing and inspection of fuel facility and certain other NMSS licensees. The implementation of some recommendations will depend on decisions to be made regarding the scope of NRC responsibilities with respect to those aspects of the design and operation of such facilities that are not directly related to radiological safety

Thermal reactions of uranium metal, UO 2, U 3O 8, UF 4, and UO 2F 2 with NF 3 to produce UF 6

Science.gov (United States)

McNamara, Bruce; Scheele, Randall; Kozelisky, Anne; Edwards, Matthew

2009-11-01

This paper demonstrates that NF 3 fluorinates uranium metal, UO 2, UF 4, UO 3, U 3O 8, and UO 2F 2·2H 2O to produce the volatile UF 6 at temperatures between 100 and 550 °C. Thermogravimetric and differential thermal analysis reaction profiles are described that reflect changes in the uranium fluorination/oxidation state, physiochemical effects, and instances of discrete chemical speciation. Large differences in the onset temperatures for each system investigated implicate changes in mode of the NF 3 gas-solid surface interaction. These studies also demonstrate that NF 3 is a potential replacement fluorinating agent in the existing nuclear fuel cycle and in actinide volatility reprocessing.

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.

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.

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

International Nuclear Information System (INIS)

Gasper, J.R.; Sutter, R.J.; Avci, H.I.

1995-01-01

The Depleted Uranium Hexafluoride (DUF 6 ) 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

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)

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

1995-01-01

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

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.

49 CFR 173.417 - Authorized fissile materials packages.

Science.gov (United States)

2010-10-01

... for export and import shipments. (2) A residual “heel” of enriched solid uranium hexafluoride may be... made in accordance with Table 2, as follows: Table 2—Allowable Content of Uranium Hexafluoride (UF6... Liters Cubic feet Maximum Uranium 235-enrichment (weight)percent Maximum “Heel” weight per cylinder UF6...

Lessons learned from recent safety related incidents at A Canadian uranium conversion facility

International Nuclear Information System (INIS)

Jaferi, Jafir

2013-01-01

This paper presents the Canadian Nuclear Safety Commission's (CNSC) regulatory requirements for nuclear fuel facility licensees to report any situation or incident that results or is likely to result in a hazard to the health or safety of any person or the environment and to submit its incident investigation report with cause(s) of the incident and corrective actions taken or planned. In addition, the paper presents two recent safety-related incidents that occurred at a uranium conversion facility in Canada along with their consequences, causes, corrective actions and any lessons learned. The first incident resulted in a release of uranium hexafluoride (UF6) inside the UF6 cylinder filling station and the second one resulted in a spill of uranium tetrafluoride (UF 4 ) slurry inside the UF6 plant. Both incidents had no impact on the workers or the environment. (authors)

A nuclear criticality safety assessment of the loss of moderation control in 2 1/2 and 10-ton cylinders containing enriched UF6

International Nuclear Information System (INIS)

Newvahner, R.L.; Pryor, W.A.

1991-01-01

Moderation control for maintaining nuclear criticality safety in 2-1/2-ton, 10-ton, and 14-ton cylinders containing enriched uranium hexafluoride (UF 6 ) has been used safely within the nuclear industry for over thirty years, and is dependent on cylinder integrity and containment. This assessment evaluates the loss of moderation control by the breaching of containment and entry of water into the cylinders. The first objective of this study was to estimate the required amounts of water entering these large UF 6 cylinders to react with, and to moderate the uranium compounds sufficiently to cause criticality. Hypothetical accident situations were modeled as a uranyl fluoride (UO 2 F 2 ) slab above a UF 6 hemicylinder, and a UO 2 sphere centered within a UF 6 hemicylinder. These situations were investigated by computational analyses utilizing the KENO V.a Monte Carlo Computer Code. The results were used to estimate both the masses of water required for criticality, and the limiting masses of water that could be considered safe. The second objective of the assessment was to calculate the time available for emergency control actions before a criticality would occur, i.e., a ''safetime,'' for various sources of water and different size openings in a breached cylinder. In the situations considered, except the case for a fire hose, the safetime appears adequate for emergency control actions. The assessment shows that current practices for handling moderation controlled cylinders of low enriched UF 6 , along with the continuation of established personnel training programs, ensure nuclear criticality safety for routine and emergency operations. 2 refs., 5 figs., 1 tab

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.

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)

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

1995-01-01

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

A nuclear criticality safety assessment of the loss of moderation control in 2 1/2 and 10-ton cylinders containing enriched UF{sub 6}

Energy Technology Data Exchange (ETDEWEB)

Newvahner, R.L. [Martin Marietta Energy Systems, Inc., Piketon, OH (United States); Pryor, W.A. [PAI Corp., Oak Ridge, TN (United States)

1991-12-31

Moderation control for maintaining nuclear criticality safety in 2 {1/2}-ton, 10-ton, and 14-ton cylinders containing enriched uranium hexafluoride (UF{sub 6}) has been used safely within the nuclear industry for over thirty years, and is dependent on cylinder integrity and containment. This assessment evaluates the loss of moderation control by the breaching of containment and entry of water into the cylinders. The first objective of this study was to estimate the required amounts of water entering these large UF{sub 6} cylinders to react with, and to moderate the uranium compounds sufficiently to cause criticality. Hypothetical accident situations were modeled as a uranyl fluoride (UO{sub 2}F{sub 2}) slab above a UF{sub 6} hemicylinder, and a UO{sub 2}F{sub 2} sphere centered within a UF{sub 6} hemicylinder. These situations were investigated by computational analyses utilizing the KENO V.a Monte Carlo Computer Code. The results were used to estimate both the masses of water required for criticality, and the limiting masses of water that could be considered safe. The second objective of the assessment was to calculate the time available for emergency control actions before a criticality would occur, i.e., a {open_quotes}safetime{close_quotes}, for various sources of water and different size openings in a breached cylinder. In the situations considered, except the case for a fire hose, the safetime appears adequate for emergency control actions. The assessment shows that current practices for handling moderation controlled cylinders of low enriched UF{sub 6}, along with the continuation of established personnel training programs, ensure nuclear criticality safety for routine and emergency operations.

HEU to LEU Conversion and Blending Facility: UF6 blending alternative to produce LEU UF6 for commercial use

International Nuclear Information System (INIS)

1995-09-01

US DOE is examining options for disposing of surplus weapons-usable fissile materials and storage of all weapons-usable fissile materials; the nuclear material will be converted to a form more proliferation- resistant than the original form. Examining options for increasing the proliferation resistance of highly enriched uranium (HEU) is part of this effort. Five technologies for blending HEU will be assessed; blending as UF 6 to produce a UF 6 product for commercial use is one of them. This document provides data to be used in the environmental impact analysis for the UF 6 blending HEU disposition option. Resource needs, employment needs, waste and emissions from plant, hazards, accident scenarios, and intersite transportation are discussed

Contribution to the study of interactions between uranium hexafluoride and alkali fluorides

International Nuclear Information System (INIS)

Paillet, Alain

1972-01-01

The author describes the complexation of UF 6 with alkaline fluorides by various ways: a preliminary chemical study of the synthesis, a spectrographic study (diffraction of X-rays, Raman-laser spectroscopy, I.R. spectroscopy), a calorimetric study, at last a study of kinetics by thermogravimetry. The complexes present the formula MF, UF 6 or 2MF, UF 6 whatever is M (including Rb and Cs). The X ray diffraction study, made for analytical purposes, enabled to describe the spectra of NaUF 7 , Na 2 UF 8 , KUF 7 , RbUF 7 , CsUF 7 . For KUF 7 , RbUF 7 , CsUF 7 the tri-periodic array of the uranium atoms is cubic. The thermodynamical study shows that the initial stage of germination evolves, at room temperature, 40 or CO Kcal/mole for a reaction rate, lower than 5%, for all the complexes; then, approximately 16 Kcal/mole. For the ulterior stages, the activation energy for the inter-crystalline diffusion is about 6 Kcal/mole. Various types of original apparatus, working in fluorinating atmosphere, are described: particularly a miniaturized microcalorimeter, especially designed to gain a great sensitivity. (author) [fr

Selection of a management strategy for depleted uranium

International Nuclear Information System (INIS)

Patton, S.; Hanrahan, E.; Bradley, C. Jnr.

1995-01-01

A consequence of the uranium enrichment process is the accumulation of a significant amount of depleted uranium hexafluoride (UF 6 ). Currently, in the United States approximately 560 000 tonnes of the material are stored at three different sites. The US Department of Energy (DOE) has recently initiated a programme to consider alternative strategies for the cost-effective and environmentally safe long-term management of this inventory of depleted UF 6 . The programme involves a technology and engineering assessment of proposed management options (which are: 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. Because of its provisions for considering a wide range of relevant issues and involving the public, this programme has become a model for future DOE materials disposition programmes. This paper presents an overview of the Depleted Uranium Hexafluoride Management Programme. Technical findings of the programme to date are presented, and major issues involved in selecting and implementing a management strategy are discussed. (author)

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 krUF6 and UF5 after laser photolysis of the UF6 gas sample.

Uranium hexafluoride and uranyl nitrate. Ionometric determination of bromine

International Nuclear Information System (INIS)

Anon.

Bromine was determined in uranium hexafluoride. The method is suitable for determining 2 to 20 ppm with respect to uranium. Bromides are oxidized by potassium permanganate to give bromine which is extracted into carbon tetrachloride, reduced by ascorbic acid and determined by ionometry [fr

Minimum critical masses for uranium at the Portsmouth Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Tayloe, R.W. Jr.; Davis, T.C.

1994-06-01

This report presents a tabulation of safe masses and minimum critical masses for uranium (U). These minimum critical mass and safe mass tables were obtained by interpolating between the values reported in the literature to obtain values as a function of enrichment within the 1.5 percent to 100 percent range. Equivalent mass values for uranium-235 (U 235 ), uranium hexafluoride (UF 6 ), and uranyl fluoride (UO 2 F 2 ) have been generated from the safe mass and minimum critical masses for uranium

Experimental determination of the thickness of aluminum cascade pipes in the presence of UF{sub 6} gas during enrichment measurements

Energy Technology Data Exchange (ETDEWEB)

Lombardi, M.L., E-mail: lombardi@lanl.gov [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos NM 87545 (United States); Favalli, A.; Goda, J.M.; Ianakiev, K.D.; MacArthur, D.W.; Moss, C.E. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos NM 87545 (United States)

2012-04-21

We present a method of determining the wall thickness of a pipe in a Gas Centrifuge Enrichment Plant (GCEP) when an empty pipe measurement is not feasible. Our method uses an X-ray tube for transmission measurements and a lanthanum bromide (LaBr{sub 3}) scintillation detector on the opposite side of the pipe. Two filters, molybdenum (K-edge 20.0 keV) and palladium (K-edge 24.35 keV) are used to transform the bremsstrahlung spectra produced by the X-ray tube into more useful, sharply peaked, spectra. The maximum energies of the peaks are determined by the K-edges of the filters. The attenuation properties of the uranium hexafluoride (UF{sub 6}) gas allow us to determine wall thickness by looking at the ratio of selected regions of interest (ROIs) of the Mo and Pd transmitted spectra. While the attenuation factor at these two transmission energies in the UF{sub 6} gas is nearly equal, attenuation in the aluminum pipe wall at these two energies differs by a factor of about 60. This difference allows measurement of attenuation in the pipe independent of attenuation in the UF{sub 6} gas. Feasibility studies were performed using analytical calculations, and filter thicknesses were optimized. In order to experimentally validate our attenuation measurement method, a UF{sub 6} source with variable enrichment and pipe thickness was built. We describe the experimental procedure used to verify our previous calculations and present recent results.

HEU to LEU Conversion and Blending Facility: UF{sub 6} blending alternative to produce LEU UF{sub 6} for commercial use

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-09-01

US DOE is examining options for disposing of surplus weapons-usable fissile materials and storage of all weapons-usable fissile materials; the nuclear material will be converted to a form more proliferation- resistant than the original form. Examining options for increasing the proliferation resistance of highly enriched uranium (HEU) is part of this effort. Five technologies for blending HEU will be assessed; blending as UF{sub 6} to produce a UF{sub 6} product for commercial use is one of them. This document provides data to be used in the environmental impact analysis for the UF{sub 6} blending HEU disposition option. Resource needs, employment needs, waste and emissions from plant, hazards, accident scenarios, and intersite transportation are discussed.

The action of uranium hexafluoride on some metallic fluorides (1962); Action de l'hexafluorure d'uranium sur quelques fluorures metalliques (1962)

Energy Technology Data Exchange (ETDEWEB)

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

1961-12-15

A metallic difluoride is inert to UF{sub 6} unless the metal can exist in a higher valency state. In this case, UF{sub 6} acts as an oxidising agent and is transformed into UF{sub 4}. 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 U{sub 4}F{sub 17}. 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: MeF{sub 3}, 0,562 UF{sub 6}; MeF{sub 4}, 0,396 UF{sub 6} which are in good agreement with chemical measurements. (author) [French] Un di-fluorure metallique est inerte vis-a-vis de UF{sub 6}, sauf si le metal est susceptible d'exister a une valence plus elevee. Dans ce cas, UF{sub 6} joue le role d'un oxydant et se transforme en UF{sub 4}. Les fluorures de metaux tri et tetravalents donnent naissance a des composes nouveaux quand ils sont maintenus a haute temperature (500 deg. C) en presence de vapeur d'hexafluorure d'uranium. Les produits obtenus sont caracterises par leurs diagrammes de diffraction X. Les distributions de raies des diagrammes de poudre sont tres voisines de celles de U{sub 4}F{sub 17}. En supposant que cette analogie resulte d'un empilement d'ions fluor identique, le calcul conduit aux formules theoriques suivantes: MeF{sub 3}, 0,562 UF{sub 6}; MeF{sub 4}, 0,396 UF{sub 6} en bon accord avec les resultats des dosages chimiques. (auteur)

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.

Obtaining of uranium tetrafluoride UF4 by electrodialysis reactive from uranium concentrates

International Nuclear Information System (INIS)

Munoz Lay, Danny Mauricio

2014-01-01

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

Monitoring the mass of UF6 gas and uranium deposits in aluminium pipes using X-ray fluorescence and X-ray transmission gauges

International Nuclear Information System (INIS)

Packer, T.W.; Smith, S.M.

1984-12-01

In order to determine the enrichment of UF 6 gas in centrifuge plant pipework it is necessary to measure the mass of the gas (pressure) and the mass per unit area of any uranium deposited on the pipe. This paper shows that it is possible to determine the pressure of the UF 6 gas in pipes 120 mm in diameter using an energy-dispersive X-ray fluorescence spectrometer. Results are also given of transmission measurements made using a low power X-ray generator operated at two different applied voltages. A method of using the two measurements to determine the mass per unit area of deposited uranium is described. (author)

Synthesis and characterization of a new uranium(V) compound: H3O+UF6-

International Nuclear Information System (INIS)

Masson, J.P.; Desmoulin, J.P.; Charpin, P.; Bougon, R.

1976-01-01

The reaction of equimolar amounts of UF 5 and H 2 O in hydrogen fluoride results in the partial dissolution of UF 5 , yielding a blue-green solution from which the new salt oxonium hexafluorouranate(V)(H 3 O + UF 6 - ) could be isolated as a green crystalline solid. Calorimetric measurements showed H 3 O + UF 6 - to decompose at about 68 0 C and its heat of formation to be equal to -628 +- 2 kcal mol. Its ionic nature in the solid state and in HF solutions was demonstrated from vibrational and electronic spectra. The electronic spectrum is closely similar to those of LiUF 6 , NaUF 6 , and CsUF 6 and differs from those of RbUF 6 and KUF 6 . This adduct shows a strong ESR signal, with g = -0.78 +- 0.10, characteristic of UF 6 - salts. Based on its x-ray powder diffraction pattern, H 3 O + UF 6 - is cubic with a = 5.2229 +- 0.0005 A

Production of uranium dioxide

International Nuclear Information System (INIS)

Hart, J.E.; Shuck, D.L.; Lyon, W.L.

1977-01-01

A continuous, four stage fluidized bed process for converting uranium hexafluoride (UF 6 ) to ceramic-grade uranium dioxide (UO 2 ) powder suitable for use in the manufacture of fuel pellets for nuclear reactors is disclosed. The process comprises the steps of first reacting UF 6 with steam in a first fluidized bed, preferably at about 550 0 C, to form solid intermediate reaction products UO 2 F 2 , U 3 O 8 and an off-gas including hydrogen fluoride (HF). The solid intermediate reaction products are conveyed to a second fluidized bed reactor at which the mol fraction of HF is controlled at low levels in order to prevent the formation of uranium tetrafluoride (UF 4 ). The first intermediate reaction products are reacted in the second fluidized bed with steam and hydrogen at a temperature of about 630 0 C. The second intermediate reaction product including uranium dioxide (UO 2 ) is conveyed to a third fluidized bed reactor and reacted with additional steam and hydrogen at a temperature of about 650 0 C producing a reaction product consisting essentially of uranium dioxide having an oxygen-uranium ratio of about 2 and a low residual fluoride content. This product is then conveyed to a fourth fluidized bed wherein a mixture of air and preheated nitrogen is introduced in order to further reduce the fluoride content of the UO 2 and increase the oxygen-uranium ratio to about 2.25

Airborne uranium, its concentration and toxicity in uranium enrichment facilities

International Nuclear Information System (INIS)

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

1979-02-01

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

Corrosion of Al-7075 by uranium hexafluoride

International Nuclear Information System (INIS)

1989-01-01

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

Corrosion of breached UF6 storage cylinders

International Nuclear Information System (INIS)

Barber, E.J.; Taylor, M.S.; DeVan, J.H.

1993-01-01

This paper describes the corrosion processes that occurred following the mechanical failure of two steel 14-ton storage cylinders containing depleted UF 6 . The failures both were traced to small mechanical tears that occurred during stacking of the cylinders. Although subsequent corrosion processes greatly extended the openings in the wall. the reaction products formed were quite protective and prevented any significant environmental insult or loss of uranium. The relative sizes of the two holes correlated with the relative exposure times that had elapsed from the time of stacking. From the sizes and geometries of the two holes, together with analyses of the reaction products, it was possible to determine the chemical reactions that controlled the corrosion process and to develop a scenario for predicting the rate of hydrolysis of UF 6 , the loss rate of HF, and chemical attack of a breached UF 6 storage cylinder

Processing of stored uranium tetrafluoride for productive use

International Nuclear Information System (INIS)

Whinnery, W.N. III

1987-01-01

Waste uranium tetrafluoride (UF4) was created from converting uranium hexafluoride (UF6) to UF4 for generation of hydrogen fluoride. This resulted in more tails cylinders being made available in the early days of the Paducah Gaseous Diffusion Plant. A need arose for the UF4; however, a large portion of the material was stored outside in 55-gallon drums where the material became caked and very hard. Chemical operations crushed, ground, and screened a large portion of the waste UF4 from 1981-1987. Over 111,935,000 pounds of the material has been processed and put into productive use at Westinghouse Materials Company of Ohio or at Department of Defense facilities. This long-term effort saved the disposal cost of the material which is estimated at $9,327,900. In addition, the work was for an outside contract which lowered the operating cost of the Chemical Operations Department by $4,477,400. Disposal options for the material still present in the current inventory are outlined

Synthesis of graphite intercalation compound of group VI metals and uranium hexafluorides

International Nuclear Information System (INIS)

Fukui, Toshihiro; Hagiwara, Rika; Ema, Keiko; Ito, Yasuhiko

1993-01-01

Systematic investigations were made on the synthesis of graphite intercalation compounds of group VI transition metals (W and Mo) and uranium hexafluorides. The reactions were performed by interacting liquid or gaseous metal hexafluorides with or without elemental fluorine at ambient temperature. The degree of intercalation of these metal fluorides depends on the formation enthalpy of fluorometallate anion from the original metal hexafluoride, as has been found for other intercalation reactions of metal fluorides. (author)

New method for conversion of uranium hexafluoride to uranium dioxide

International Nuclear Information System (INIS)

Nakabayashi, S.; Suzuki, M.; Tanaka, H.

1987-01-01

Five different methods for conversion of UF 6 to ceramic-grade UO 2 powder have been developed to industrial scale. Two of them, the ammonium diuranate (ADU) and AUC processes, are based on precipitation of uranium compounds from aqueous solutions. The other three follow a dry route in which UF 6 is hydrolyzed and reduced by steam and hydrogen using fluidized bed techniques, rotating kilns, or flame chemistry methods. The ADU process has the advantage of flexible product powder characteristics, while disadvantages include a large quantity of waste, low powder fluidity, and a complicated process. On the other hand, the dry process using fluidized-bed techniques has the advantages of hydrofluoric acid recovery, a free-flowing powder, and process simplicity, but the disadvantages of poorer ceramic properties for the product. The new method developed at Mitsubishi Metal Corp. is a semidry process, which has well-balanced merits over the ADU process and the dry process using fluidized-bed techniques. This process is very attractive from powder characteristics, process simplicity, and waste reduction

Removal of hydrogen fluoride from uranium plant emissions

International Nuclear Information System (INIS)

Ramani, M.P.S.

1997-01-01

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 UF 4 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

Investigation of transformation of uranium hexafluoride into dioxide

International Nuclear Information System (INIS)

Galkin, N.P.; Veryatin, U.D.; Yakhonin, I.F.; Logunov, A.F.; Dymkov, Yu.M.

1982-01-01

The process of transformation of uranium hexafluoride into dioxide using the method of pyrohydrolysis by steam-hydrogen mixture in a boiling layer using uranium dioxide granules applicable for production of fuel elements is considered. Technological parameters and equipment of the process are described, intermediate stages and process products are considered. Physicochemical and physicomechanical properties of the obtained uranium dioxide granules are given. The results of metallographical investigations into solid products of pyrohydrolysis in phase transformations at certain stages of the process as well as test on vibration packing of the obtained granules in fuel cans are presented

Preparation of small uranium hexafluoride samples in view of mass spectrometry analysis; Preparation de petits echantillons d'hexafluorure d'uranium en vue d'analyse spectrometrique de masse

Energy Technology Data Exchange (ETDEWEB)

Severin, Michel

1958-07-01

We have studied the preparation of uranium hexafluoride for the determination of the isotopic ratio {sup 235}U/{sup 238}U by means of a mass spectrometer. UF{sub 6} should be produced from an amount of raw material (metallic uranium or oxide) that should not exceed 0,1 g. Our method has a good yield (we have studied the rate of transformation) and gives samples which present a content of impurities (HF and SiF{sub 4}) low enough to enable correct isotopic measurements. The method which seemed the best uses the cobalt trifluoride as a fluorining agent. It is now in current use in the laboratories of mass spectrometry. (author) [French] Nous avons etudie la preparation de l'hexafluorure d'uranium en vue de la determination au spectrometre de masse du rapport isotopique {sup 235}U/{sup 238}U. L'hexafluorure d'uranium devait etre produit a partir d'une quantite de matiere premiere (uranium metallique ou oxyde) ne devant pas exceder 0,1 g. Nous avons mis au point une methode de preparation presentant un rendement eleve (etude du taux de transformation) et donnant des echantillons dont le taux d'impuretes (HF et SiF{sub 4}) est suffisamment faible pour permettre des mesures isotopiques correctes. La methode ayant donne le plus de satisfaction utilise le trifluorure de cobalt comme agent fluorant. Ce procede est maintenant couramment employe dans les laboratoires de spectrometrie de masse. (auteur)

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

International Nuclear Information System (INIS)

Batyrbekov, G.A.; Belyakova, Eh.A.

1996-01-01

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 F 6 utilization as nuclear fuel, the utilization of U F 6 as volume source o ionization, search of active laser media compatible with U F 6 that is complicated by lack of constant rates data for most of plasma-chemical reactions with U F 6 and his dissociation products. Cylindrical probe volt-ampere characteristics (VAC) measured in U F 6 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

Test emission of uranium hexafluoride in atmosphere. Results interpretation

International Nuclear Information System (INIS)

Crabol, B.; Deville-Cavelin, G.

1989-01-01

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 [fr

The study of the possibilities for the processing and exploatation of nuclear raw materials

International Nuclear Information System (INIS)

Smalc, A.

1977-01-01

Laboratory scale fluorinations of uranium tetrafluoride with elemental fluorine under pressure and the reactions of uranium hexafluoride with boron trioxide and sulphur are described. A review of the reactions with UF 6 and the processes for the conversion of UF 6 into non-volatile uranium compounds is given

Criticality Safety Evaluation for 30B and 48X UF6 Cylinders for Transportation and Storage

International Nuclear Information System (INIS)

Mokhatri, Homami Zahra; Nematollahi, Mohammadreza; Kamyab, Shahabeddin

2011-01-01

30B and 48X cylinders are two standard containers have been used for transportation and storage of uranium hexafluoride with 21/2-ton and 10-ton loading capacity, respectively. For the sake of nuclear safety, the long-term safe storage and transportation of the cylinders are necessary to be concerned. Safe limits in handling and storage of 30B and 48X cylinders from the criticality safety considerations, has been investigated in this paper, by using the MCNP.4C code with ENDF/B-VI library data for the neutron cross sections. An infinite array model (with and without over pack) incorporating an internal H/U ratio of 0.088 was then developed to determine the optimal interstitial moderation. The maximum k eff value for the conditions of optimal interstitial moderation with the premise of no water leakage into the UF 6 cylinder has been shown to be 0.79209 ± 0.0011 for the 30B cylinder and 0.7625±0.0013 for 48X cylinder with 5 wt % 235 U enrichment. Based on this evaluation, the 30B and 48X UF 6 cylinders with 5 wt % 235 U enrichment meet the 10 CFR part 71 criteria for Fissile Class I packages, even in the worst case, and has a Transport Index (TI) of zero for criticality safety purposes

Emergency preparedness and response in case of a fire accident with UF6 packages traversing the Suez Canal

International Nuclear Information System (INIS)

Salama, M.

2004-01-01

Egypt has a unique problem, the Suez Canal. Radioactive cargo passes regularly through the canal carrying new and spent reactor fuel. There are also about 1000 metric tonnes of uranium hexafluoride (UF 6 ) passing through the canal every year. In spite of all the precautions taken in the transport, accidents with packages containing UF 6 shipped through the Suez Canal may arise, even though the probability is minimal. Such accidents may be accompanied by injuries to or death of persons and damage to property including radiation and criticality hazards and high chemical toxicity, particularly if the accident occurred close to one of the three densely populated cities (Port Said, Ismailia and Suez), which are located along the west bank of the Suez Canal. The government of Egypt has established a national radiological emergency plan in order to deal with any radiological accidents which may arise inside the country. This paper considers the effect of a fire accident to industrial packages containing UF 6 on board a cargo ship passing along the Suez Canal near Port Said City. The accident scenario and emergency response actions taken during the different phases of the accident are presented and discussed. The paper highlights the importance of public awareness for populations located in densely populated areas along the bank of the Suez Canal, in order to react in a timely and effective way to avoid the toxic and radiological hazards resulting from such a type of accident. The possibility of upgrading the capabilities of civil defence and fire-fighting personnel is also discussed (author)

Study of neptunium hexafluoride formation and its adsorption on metallic fluorides

International Nuclear Information System (INIS)

Matcheret, Georges

1970-01-01

This report involves two parts. The first part deals with the action of elementary fluorine on neptunium compounds by a thermogravimetric method. The mechanism and the kinetics of this reaction vary according to the nature of the compound. 1 - With neptunium tetrafluoride the reaction, proceeds in a single step. The kinetics corresponds to a uniform attack of the entire surface of the sample and follows the kinetics law: (1-α) 1/3 1-k rel t . 2 - The reaction with neptunium dioxyde involves two steps, neptunium tetrafluoride being the intermediate compound. The kinetics of the first step corresponds to a diffusion process and follows the kinetic law: log (1-α) = kt 1/2 . The kinetics of the second step corresponds to an uniform attack of the entire sur face of the sample. The object of the second part is a study of the adsorption of uranium hexafluoride and neptunium hexafluoride on sodium, magnesium and barium fluorides by a volumetric method. The adsorption of UF 6 on MgF 2 has been investigated at 20 deg. C. The isothermal curve obtained is characteristic of a physical one layer monomolecular adsorption. In a way similar to the behaviour of UF 6 the adsorption of NpF 6 involves in addition a chemical reduction with formation of NpF 5 and release of fluorine. The reaction of NpF 6 with BaF 2 permitted to confirm the influence of the polarizing power of the Ba ++ ion on formation and stability of the product of addition. (author) [fr

Depleted uranium: A DOE management guide

International Nuclear Information System (INIS)

1995-10-01

The U.S. Department of Energy (DOE) has a management challenge and financial liability in the form of 50,000 cylinders containing 555,000 metric tons of depleted uranium hexafluoride (UF 6 ) that are stored at the gaseous diffusion plants. The annual storage and maintenance cost is approximately $10 million. This report summarizes several studies undertaken by the DOE Office of Technology Development (OTD) to evaluate options for long-term depleted uranium management. Based on studies conducted to date, the most likely use of the depleted uranium is for shielding of spent nuclear fuel (SNF) or vitrified high-level waste (HLW) containers. The alternative to finding a use for the depleted uranium is disposal as a radioactive waste. Estimated disposal costs, utilizing existing technologies, range between $3.8 and $11.3 billion, depending on factors such as applicability of the Resource Conservation and Recovery Act (RCRA) and the location of the disposal site. The cost of recycling the depleted uranium in a concrete based shielding in SNF/HLW containers, although substantial, is comparable to or less than the cost of disposal. Consequently, the case can be made that if DOE invests in developing depleted uranium shielded containers instead of disposal, a long-term solution to the UF 6 problem is attained at comparable or lower cost than disposal as a waste. Two concepts for depleted uranium storage casks were considered in these studies. The first is based on standard fabrication concepts previously developed for depleted uranium metal. The second converts the UF 6 to an oxide aggregate that is used in concrete to make dry storage casks

Investigation of technology for the monitoring of UF6 mass flow in UF6 streams diluted with H2

International Nuclear Information System (INIS)

Baker, O.J.; Cooley, J.N.; Hewgley, W.A.; Moran, B.W.; Swindle, D.W. Jr.

1986-12-01

The applicability, availability, and effectiveness of gas flow meters are assessed as a means for verifying the mass flows of pure UF 6 streams diluted with a carrier gas. The initial survey identified the orifice, pitot tube, thermal, vortex shedding, and vortex precession (swirl) meters as promising for the intended use. Subsequent assessments of these flow meters revealed that two - the orifice meter and the pitot tube meter - are the best choices for the proposed applications: the first is recommended for low velocity gas, small diameter piping; the latter, for high velocity gas, large diameter piping. Final selection of the gas flow meters should be based on test loop evaluations in which the proposed meters are subjected to gas flows, temperatures, and pressures representative of those expected in service. Known instruments are evaluated that may be applicable to the measurement of uranium or UF 6 concentration in a UF 6 - H 2 process stream at an aerodynamic enrichment plant. Of the six procedures evaluated, four have been used for process monitoring in a UF 6 environment: gas mass spectrometry, infrared-ultraviolet-visible spectrophotometry, gas chromatography, and acoustic gas analysis. The remaining two procedures, laser fluorimetry and atomic absorption spectroscopy, would require significant development work before they could be used for process monitoring. Infrared-ultravioloet-visible spectrophotometry is judged to be the best procedure currently available to perform the required measurement

Department of Energy depleted uranium recycle

International Nuclear Information System (INIS)

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

1994-01-01

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

Conversion of U3O8 to UF6

International Nuclear Information System (INIS)

Bodu, R.L.

1975-01-01

Three main processes for the production of UF 6 from the uranium ores (yellow cake) is described. The economic aspects of the conversion - capital cost, operating costs and conversion market and the future of conversion - capacity and prices - are discussed. (HPH) [de

Hydrofluoric Acid Corrosion Testing on Unplated and Electroless Gold-Plated Samples

International Nuclear Information System (INIS)

Osborne, P.E.; Icenhour, A.S.; Del Cul, G.D.

2000-01-01

The Molten Salt Reactor Experiment (MSRE) remediation requires that almost 40 kg of uranium hexafluoride (UF6) be converted to uranium oxide (UO). In the process of this conversion, six moles of hydrofluoric acid (HP) are produced for each mole of UF6 converted

Reimiep 87. An interlaboratory U-235 enrichment determination by gamma measurement on solid UF6 sample

International Nuclear Information System (INIS)

Aparo, M.; Cresti, P.

1988-01-01

Gamma spectroscopy technique, based on the measurement of U 235 186 KeV flux, is now currently used for the determination of Uranium enrichment in different material of nuclear fuel cycle, namely: Uranium metallic, UO 2 pellets, UF 6 liquid or solid. The present paper describes the use of such a technique and the obtained results in determining the U 235 /U atomic isotopic abundance on a certified UF 6 solid sample. The measurements have been carried out in the frame work of the partecipation to the ''UF 6 Interlaboratory Measurements Evaluation Programme'' organized by CBNM/Geel with the support of the ESARDA (European Safeguards Research and Development Association)

Evaluation of coverage of enriched UF6 cylinder storage lots by existing criticality accident alarms

International Nuclear Information System (INIS)

Lee, B.L. Jr.; Dobelbower, M.C.; Woollard, J.E.; Sutherland, P.J.; Tayloe, R.W. Jr.

1995-03-01

The Portsmouth Gaseous Diffusion Plant (PORTS) is leased from the US Department of Energy (DOE) by the United States Enrichment Corporation (USEC), a government corporation formed in 1993. PORTS is in transition from regulation by DOE to regulation by the Nuclear Regulatory Commission (NRC). One regulation is 10 CFR Part 76.89, which requires that criticality alarm systems be provided for the site. PORTS originally installed criticality accident alarm systems in all building for which nuclear criticality accidents were credible. Currently, however, alarm systems are not installed in the enriched uranium hexafluoride (UF 6 ) cylinder storage lots. This report analyzes and documents the extent to which enriched UF 6 cylinder storage lots at PORTS are covered by criticality detectors and alarms currently installed in adjacent buildings. Monte Carlo calculations are performed on simplified models of the cylinder storage lots and adjacent buildings. The storage lots modelled are X-745B, X-745C, X745D, X-745E, and X-745F. The criticality detectors modelled are located in building X-343, the building X-344A/X-342A complex, and portions of building X-330 (see Figures 1 and 2). These criticality detectors are those located closest to the cylinder storage lots. Results of this analysis indicate that the existing criticality detectors currently installed at PORTS are largely ineffective in detecting neutron radiation from criticality accidents in most of the cylinder storage lots at PORTS, except sometimes along portions of their peripheries

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

International Nuclear Information System (INIS)

1981-01-01

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

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

International Nuclear Information System (INIS)

Dubrin, J.W.; Rahm-Crites, L.

1997-09-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Dubrin, J.W., Rahm-Crites, L.

1997-09-01

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.

Computational fluid dynamics tracking of UF6 reaction products release into a gaseous diffusion plant cell housing

International Nuclear Information System (INIS)

Wendel, M.W.; Chen, N.C.J.; Kim, S.H.; Taleyarkhan, R.P.; Keith, K.D.; Schmidt, R.W.

1996-01-01

A three-dimensional (3-D) computational fluid dynamics (CFD) model has been developed using CFDS-FLOW3D Version 3.3 to model the transport of aerosol products formed during a release of uranium hexafluoride (UF 6 ) into a gaseous diffusion plant (GDP) process building. As part of a facility-wide safety evaluation, a one-dimensional (1-D) analysis of aerosol/vapor transport following such an hypothesized severe accident is being performed. The objective of this study is to supplement the 1-D analysis with more detailed 3-D results. Specifically, the goal is to quantify the distribution of aerosol passing out of the process building during the hypothetical accident. This work demonstrates a useful role for CFD in large 3-D problems, where some experimental data are available for calibrating key parameters and the desired results are global (total time-integrated aerosol flow rates across a few boundary surfaces) as opposed to local velocities, temperatures, or heat transfer coefficients

From the Lab to the real world : sources of error in UF6 gas enrichment monitoring

International Nuclear Information System (INIS)

Lombardi, Marcie L.

2012-01-01

Safeguarding uranium enrichment facilities is a serious concern for the International Atomic Energy Agency (IAEA). Safeguards methods have changed over the years, most recently switching to an improved safeguards model that calls for new technologies to help keep up with the increasing size and complexity of today's gas centrifuge enrichment plants (GCEPs). One of the primary goals of the IAEA is to detect the production of uranium at levels greater than those an enrichment facility may have declared. In order to accomplish this goal, new enrichment monitors need to be as accurate as possible. This dissertation will look at the Advanced Enrichment Monitor (AEM), a new enrichment monitor designed at Los Alamos National Laboratory. Specifically explored are various factors that could potentially contribute to errors in a final enrichment determination delivered by the AEM. There are many factors that can cause errors in the determination of uranium hexafluoride (UF 6 ) gas enrichment, especially during the period when the enrichment is being measured in an operating GCEP. To measure enrichment using the AEM, a passive 186-keV (kiloelectronvolt) measurement is used to determine the 235 U content in the gas, and a transmission measurement or a gas pressure reading is used to determine the total uranium content. A transmission spectrum is generated using an x-ray tube and a 'notch' filter. In this dissertation, changes that could occur in the detection efficiency and the transmission errors that could result from variations in pipe-wall thickness will be explored. Additional factors that could contribute to errors in enrichment measurement will also be examined, including changes in the gas pressure, ambient and UF 6 temperature, instrumental errors, and the effects of uranium deposits on the inside of the pipe walls will be considered. The sensitivity of the enrichment calculation to these various parameters will then be evaluated. Previously, UF 6 gas enrichment

pVT-Second Virial Coefficients B(T ), Viscosity η(T ), and Self-Diffusion ρD(T) of the Gases: BF3, CF4, SiF4, CCl4, SiCl4, SF6, MoF6, WF6, UF6, C(CH3)4, and Si(CH3)4 Determined by Means of an Isotropic Temperature-Dependent Potential

Science.gov (United States)

Zarkova, L.; Hohm, U.

2002-03-01

We present results on self-consistent calculations of second pVT-virial coefficients B(T), viscosity data η(T), and diffusion coefficients ρD(T) for eleven heavy globular gases: boron trifluoride (BF3), carbon tetrafluoride (CF4), silicon tetrafluoride (SiF4), carbon tetrachloride (CCl4), silicon tetrachloride (SiCl4), sulfur hexafluoride (SF6), molybdenum hexafluoride (MoF6), tungsten hexafluoride (WF6), uranium hexafluoride (UF6), tetramethyl methane (C(CH3)4, TMM), and tetramethyl silane (Si(CH3)4, TMS). The calculations are performed mainly in the temperature range between 200 and 900 K by means of isotropic n-6 potentials with temperature-dependent separation rm(T) and potential well depth ɛ(T). The potential parameters at T=0 K (ɛ, rm, n) and the enlargement of the first level radii δ are obtained solving an ill-posed problem of minimizing the squared deviations between experimental and calculated values normalized to their relative experimental error. The temperature dependence of the potential is obtained as a result of the influence of vibrational excitation on binary interactions. This concept of the isotropic temperature-dependent potential (ITDP) is presented in detail where gaseous SF6 will serve as an example. The ITDP is subsequently applied to all other gases. This approach and the main part of the results presented here have already been published during 1996-2000. However, in some cases the data are upgraded due to the recently improved software (CF4, SF6) and newly found experimental data (CF4, SiF4, CCl4, SF6).

Results from a 'Proof-of-Concept' Demonstration of RF-Based Tracking of UF6 Cylinders during a Processing Operation at a Uranium Enrichment Plant

International Nuclear Information System (INIS)

Pickett, Chris A; Kovacic, Donald N; Whitaker, J Michael; Younkin, James R; Hines, Jairus B; Laughter, Mark D; Morgan, Jim; Carrick, Bernie; Boyer, Brian; Whittle, K.

2008-01-01

Approved industry-standard cylinders are used globally for processing, storing, and transporting uranium hexafluoride (UF 6 ) at uranium enrichment plants. To ensure that cylinder movements at enrichment facilities occur as declared, the International Atomic Energy Agency (IAEA) must conduct time-consuming periodic physical inspections to validate facility records, cylinder identity, and containment. By using a robust system design that includes the capability for real-time unattended monitoring (of cylinder movements), site-specific rules-based event detection algorithms, and the capability to integrate with other types of monitoring technologies, one can build a system that will improve overall inspector effectiveness. This type of monitoring system can provide timely detection of safeguard events that could be used to ensure more timely and appropriate responses by the IAEA. It also could reduce reliance on facility records and have the additional benefit of enhancing domestic safeguards at the installed facilities. This paper will discuss the installation and evaluation of a radio-frequency- (RF-) based cylinder tracking system that was installed at a United States Enrichment Corporation Centrifuge Facility. This system was installed primarily to evaluate the feasibility of using RF technology at a site and the operational durability of the components under harsh processing conditions. The installation included a basic system that is designed to support layering with other safeguard system technologies and that applies fundamental rules-based event processing methodologies. This paper will discuss the fundamental elements of the system design, the results from this site installation, and future efforts needed to make this technology ready for IAEA consideration

Integrating UF6 Cylinder RF Tracking With Continuous Load Cell Monitoring for Verifying Declared UF6 Feed and Withdrawal Operations Verifying Declared UF6 Feed and Withdrawal Operations

International Nuclear Information System (INIS)

Krichinsky, Alan M.; Miller, Paul; Pickett, Chris A.; Richardson, Dave; Rowe, Nathan C.; Whitaker, J. Michael; Younkin, James R.

2009-01-01

Oak Ridge National Laboratory is demonstrating the integration of UF6 cylinder tracking, using RF technology, with continuous load cell monitoring (CLCM) at mock UF6 feed and withdrawal (F and W) stations. CLCM and cylinder tracking are two of several continuous-monitoring technologies that show promise in providing integrated safeguards of F and W operations at enrichment plants. Integrating different monitoring technologies allows advanced, automated event processing to screen innocuous events thereby minimizing false alerts to independent inspectors. Traditionally, international inspectors rely on batch verification of material inputs and outputs derived from operator declarations and periodic on-site inspections at uranium enrichment plants or other nuclear processing facilities. Continuously monitoring F and W activities between inspections while providing filtered alerts of significant operational events will substantially increase the amount of valuable information available to inspectors thereby promising to enhance the effectiveness of safeguards and to improve efficiency in conducting on-site inspections especially at large plants for ensuring that all operations are declared.

Method and equipment for continuous transformation of UF6 into (NH4)2U2O7

International Nuclear Information System (INIS)

Fuller, R.R.

1975-01-01

Uranium hexafluoride is, in a three-stage method, transformed into ammonium diuvanate which can be calcined to UO 2 of good ceramic quality. At the solution of UF 6 in water, UO 2 F 2 and HF form in condsiderably acid solution. This aqueous hydrolysis solution is with standardized using NH 4 O 4 (24-29% NH 3 ) at a pH-value between 5.0 and 6.0 and brought into a precipitation tank. The bulk of the ammonium diuvanate then precipitating is drained in the lower portion of the tank and added again to the suspension, close to the surface of the fluid, under intensive pressure. The intensive vigorous revolution of the entire tank content affects the size of the particles and the size of the surface of the precipitating uranate as well. The equipment for the calcination of the ammonium diuvanate is described. The method represents an improvement of the method described in OS 2162578; the pellets produced are more satisfying to critical requirements. (UWI) [de

Photoionization mass spectrometry of UF6

International Nuclear Information System (INIS)

Berkowitz, J.

1979-01-01

The photoionization mass spectrum of 238 UF 6 was obtained. At 600 A = 20.66 eV, the relative ionic abundances were as follows: UF 6 + , 1.4; UF 5 + , 100; UF + , 17; UF 3 + , approx. 0.7; UF 2 + , very weak; UF + , very weak; U + , essentially zero. The adiabatic ionization potential for UF 6 was 13.897 +- 0.005 eV. The production of UF 5 + begins at approx. 887 A = 13.98 eV, at which energy the UF 6 + partial cross section abruptly declines and then levels off. This behavior suggests the vague possibility of an isotope effect. The UF 4 + signal begins at approx. 725 A = 17.10 eV, at which energy the UF 5 + signal reaches a plateau value. The UF 5 + photoionization yield curve displays some autoionization structure from its threshold to approx. 750 A

Depleted uranium hexafluoride management program : data compilation for the K-25 site

International Nuclear Information System (INIS)

Hartmann, H. M.

2001-01-01

This report is a compilation of data and analyses for the K-25 site on the Oak Ridge Reservation, Oak Ridge, Tennessee. 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 K-25 site and summarizes the potential environmental impacts that could result from continued cylinder storage and preparation of cylinders for shipment at the site. It is probable that the cylinders at the K-25 site will be shipped to another site for conversion. Because conversion and long-term storage of the entire inventory at the K-25 site are highly unlikely, these data are not presented in this report. DOE's preferred alternative is to begin converting the depleted uranium hexafluoride 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

Depleted UF6 Management Information Network - A resource for the public,

Science.gov (United States)

Depleted UF6 Management Information Network Web Site is an online repository of information about the U.S ) and DUF6, research and development efforts for beneficial uses of DU, DOE's program for management of line DUF6 Guide DUF6 Guide line Introductory information about depleted uranium: how it is created

Generic report on health effects for the US Gaseous Diffusion Plants. Sect. 8, Pt. 1

International Nuclear Information System (INIS)

Just, R.A.; Emler, V.S.

1984-06-01

Toxic substances present in uranium enrichment plants include uranium hexafluoride (UF 6 ), hydrogen fluoride (HF), uranyl fluoride (UO 2 F 2 ), chlorine (Cl 2 ), chlorine trifluoride (ClF 3 ), fluorine (F 2 ), uranium tetrafluoride (UF 4 ), and technetium (Tc). The current knowledge of the expected health effects of acute exposures to these substances is described. 10 references, 2 figures, 6 tables

Draft Environmental Impact Statement for Construction and Operation of a Depleted Uranium Hexafluoride Conversion Facility at the Paducah, Kentucky, Site

International Nuclear Information System (INIS)

2003-01-01

This document is a site-specific environmental impact statement (EIS) for construction and operation of a proposed depleted uranium hexafluoride (DUF 6 ) conversion facility at the U.S. Department of Energy (DOE) Paducah site in northwestern Kentucky (Figure S-1). The proposed facility would convert the DUF 6 stored at Paducah to a more stable chemical form suitable for use or disposal. In a Notice of Intent (NOI) published in the ''Federal Register'' (FR) 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 DUF 6 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 DUF 6 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 Paducah site; from the transportation of depleted uranium conversion products to a disposal facility; and from the transportation, sale, use, or disposal of the fluoride-containing conversion products

From the Lab to the real world : sources of error in UF {sub 6} gas enrichment monitoring

Energy Technology Data Exchange (ETDEWEB)

Lombardi, Marcie L.

2012-03-01

Safeguarding uranium enrichment facilities is a serious concern for the International Atomic Energy Agency (IAEA). Safeguards methods have changed over the years, most recently switching to an improved safeguards model that calls for new technologies to help keep up with the increasing size and complexity of today’s gas centrifuge enrichment plants (GCEPs). One of the primary goals of the IAEA is to detect the production of uranium at levels greater than those an enrichment facility may have declared. In order to accomplish this goal, new enrichment monitors need to be as accurate as possible. This dissertation will look at the Advanced Enrichment Monitor (AEM), a new enrichment monitor designed at Los Alamos National Laboratory. Specifically explored are various factors that could potentially contribute to errors in a final enrichment determination delivered by the AEM. There are many factors that can cause errors in the determination of uranium hexafluoride (UF{sub 6}) gas enrichment, especially during the period when the enrichment is being measured in an operating GCEP. To measure enrichment using the AEM, a passive 186-keV (kiloelectronvolt) measurement is used to determine the {sup 235}U content in the gas, and a transmission measurement or a gas pressure reading is used to determine the total uranium content. A transmission spectrum is generated using an x-ray tube and a “notch” filter. In this dissertation, changes that could occur in the detection efficiency and the transmission errors that could result from variations in pipe-wall thickness will be explored. Additional factors that could contribute to errors in enrichment measurement will also be examined, including changes in the gas pressure, ambient and UF{sub 6} temperature, instrumental errors, and the effects of uranium deposits on the inside of the pipe walls will be considered. The sensitivity of the enrichment calculation to these various parameters will then be evaluated. Previously, UF

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

Energy Technology Data Exchange (ETDEWEB)

Medeiros, Josue C. de; Barbosa, Rodrigo A.; Carnaval, Joao Paulo R., E-mail: josue@inb.gov.br, E-mail: rodrigobarbosa@inb.gov.br, E-mail: joaocarnaval@inb.gov.br [Industrias Nucleares do Brasil (INB), Rezende, RJ (Brazil)

2013-07-01

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({sup 235}U)/n({sup 238}U) in uranium hexafluoride (UF{sub 6} - 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 ({sup 235}UF{sub 6}). Industrias Nucleares do Brasil (INB) has used quadrupole mass spectrometry (QMS) by electron impact (EI) to perform isotopic ratio n({sup 235}U)/n({sup 238}U) 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)

Circulation system for flowing uranium hexafluoride cavity reactor experiments

International Nuclear Information System (INIS)

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

1976-01-01

Accomplishment of the UF 6 critical cavity experiments, currently in progress, and planned confined flowing UF 6 initial experiments requires development of reliable techniques for handling heated UF 6 throughout extended ranges of temperature, pressure, and flow rate. The development of three laboratory-scale flow systems for handling gaseous UF 6 at temperatures up to 500 K, pressures up to approximately 40 atm, and continuous flow rates up to approximately 50 g/s is presented. A UF 6 handling system fabricated for static critical tests currently being conducted at Los Alamos Scientific Laboratory (LASL) is described. The system was designed to supply UF 6 to a double-walled aluminum core canister assembly at temperatures between 300 K and 400 K and pressures up to 4 atm. A second UF 6 handling system designed to provide a circulating flow of up to 50 g/s of gaseous UF 6 in a closed-loop through a double-walled aluminum core canister with controlled temperature and pressure is described

Nuclear fuel technology - Determination of uranium in solutions, uranium hexafluoride and solids - Part 2: Iron(II) reduction/cerium(IV) oxidation titrimetric method

International Nuclear Information System (INIS)

2004-01-01

This first edition of ISO 7097-1 together with ISO 7097-2:2004 cancels and replaces ISO 7097:1983, which has been technically revised, and ISO 9989:1996. ISO 7097 consists of the following parts, under the general title Nuclear fuel technology - Determination of uranium in solutions, uranium hexafluoride and solids: Part 1: Iron(II) reduction/potassium dichromate oxidation titrimetric method; Part 2: Iron(II) reduction/cerium(IV) oxidation titrimetric method. This part 2. of ISO 7097 describes procedures for determination of uranium in solutions, uranium hexafluoride and solids. The procedures described in the two independent parts of this International Standard are similar: this part uses a titration with cerium(IV) and ISO 7097-1 uses a titration with potassium dichromate

Nuclear fuel technology - Determination of uranium in solutions, uranium hexafluoride and solids - Part 1: Iron(II) reduction/potassium dichromate oxidation titrimetric method

International Nuclear Information System (INIS)

2004-01-01

This first edition of ISO 7097-1 together with ISO 7097-2:2004 cancels and replaces ISO 7097:1983, which has been technically revised, and ISO 9989:1996. ISO 7097 consists of the following parts, under the general title Nuclear fuel technology - Determination of uranium in solutions, uranium hexafluoride and solids: Part 1: Iron(II) reduction/potassium dichromate oxidation titrimetric method; Part 2: Iron(II) reduction/cerium(IV) oxidation titrimetric method. This part 1. of ISO 7097 describes procedures for the determination of uranium in solutions, uranium hexafluoride and solids. The procedures described in the two independent parts of this International Standard are similar: this part uses a titration with potassium dichromate and ISO 7097-2 uses a titration with cerium(IV)

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

International Nuclear Information System (INIS)

Gajek, Z.; Mulak, J.

1987-01-01

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

Calculational criticality analyses of 10- and 20-MW UF6 freezer/sublimer vessels

International Nuclear Information System (INIS)

Jordan, W.C.

1993-02-01

Calculational criticality analyses have been performed for 10- and 20-MW UF 6 freezer/sublimer vessels. The freezer/sublimers have been analyzed over a range of conditions that encompass normal operation and abnormal conditions. The effects of HF moderation of the UF 6 in each vessel have been considered for uranium enriched between 2 and 5 wt % 235 U. The results indicate that the nuclearly safe enrichments originally established for the operation of a 10-MW freezer/sublimer, based on a hydrogen-to-uranium moderation ratio of 0.33, are acceptable. If strict moderation control can be demonstrated for hydrogen-to-uranium moderation ratios that are less than 0.33, then the enrichment limits for the 10-MW freezer/sublimer may be increased slightly. The calculations performed also allow safe enrichment limits to be established for a 20-NM freezer/sublimer under moderation control

Confirmatory measurements of UF6 using the neutron self-interrogation method

International Nuclear Information System (INIS)

Stewart, J.E.; Ensslin, N.; Menlove, H.O.; Cowder, L.R.; Polk, P.J.

1985-01-01

A passive neutron counting method has been developed for measurement of the 235 U mass in Model 5A cylinders of UF 6 . The unique neutronic properties of UF 6 containing highly enriched uranium (HEU) permit 235 U assay using only passive neutron counting. The sample effectively assays itself by self-interrogation. Shipped from enrichment plants and received at fuel fabrication and conversion facilities, 5A UF 6 cylinders hold up to approx.17 kg of 235 U each. Field measurements at the Portsmouth Gaseous Diffusion Plant (GDP) showed an average assay accuracy of 6.8% (1sigma) for 44 cylinders with enrichments from 6 to 98% and with a range of fill heights. Further measurements on 38 cylinders containing 97%-enriched material yielded an accuracy of 2.8% (1sigma). Typical counting times for these measurements were less than 5 min. An in-plant instrument for receipts confirmation measurements of 5A UF 6 cylinders has been developed for the Savannah River Plant. The Receipts Assay Monitor (RAM) is currently being tested and calibrated. It is designed to confirm declared fissile mass in all incoming 5A cylinders containing HEU in the form of UF 6 . One of the computer-controlled features is a removable cadmium liner for the sample cavity. The liner allows a sample fill-height correction, which significantly improves assay accuracy

Processing device for gaseous waste containing uranium hexafluoride

International Nuclear Information System (INIS)

Hirosawa, Jun-ichi.

1985-01-01

Purpose: To enable to detect the inactivation of chemical traps thereby reduce the amount of adsorbents. Constitution: Two chemical traps are disposed in series and γ-detector for detecting γ-rays generated from U-235 in hexafluoride is disposed to the outer surface of a pipeway connecting these two chemical traps. Further, chemical traps are adapted to be swtichable between the first stage and the second stage thereof by the ON-OFF operation of a valve. Then, by determining γ-rays from U-235 at the pipeway downstream from the gas exit of the chemical traps, the counted value for the γ-rays is substantially at the background level so long as the chemical trap has an adsorbing performance for uranium hexafluoride. Then, since the γ-ray counted value is increased at the step upon inactivation of the chemical trap, the inactivation of the trap can be detected. (Yoshino, Y.)

Chemical toxicity of uranium hexafluoride compared to acute effects of radiation

International Nuclear Information System (INIS)

McGuire, S.A.

1991-02-01

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/m 3 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/m 3 (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

Chemical toxicity of uranium hexafluoride compared to acute effects of radiation

Energy Technology Data Exchange (ETDEWEB)

McGuire, S.A.

1991-02-01

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/m{sup 3} 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/m{sup 3} (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.

Development of ammonium uranyl carbonate reduction to uranium dioxide using fluidized bed

International Nuclear Information System (INIS)

Gomes, R.P.; Riella, H.G.

1988-01-01

Laboratory development of Ammonium Uranyl Carbonate (AUC) reduction to uranium dioxide (UO 2 ) using fluidized bed furnace technique is described. The reaction is carried out at 500-550 0 C using hydrogen, liberated from cracking of ammonia, as a reducing agent. As the AUC used is obtained from uranium hexafluoride (UF 6 ) it contains considerable amounts of fluoride ( - 500μgF - /gTCAU) as contaminant. The presence of fluoride leads to high corrosion rates and hence the fluoride concentrations is reduced by pyrohydrolisis of UO 2 . Physical and Chemical proterties of the final product (UO 2 ) obtained were characterized. (author) [pt

Development of solid materials for UF₆ sampling: FY16 Annual Report

Energy Technology Data Exchange (ETDEWEB)

Smith, Nicholas [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Savina, Joseph [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Hebden, Andrew [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division

2016-10-31

A handheld implementation of the ABACC-developed Cristallini method, which captures uranium hexafluoride samples as an inert salt, was organized in FY17 and succeeded in demonstrating the handheld sampler concept with reactive hexafluoride gases. The Cristallini method relies on the use of a hydrated substrate to react the incoming hexafluoride resulting in the formation of a stable uranyl fluoride salt. The Cristallini method has been demonstrated as a facility modification installed near the sampling tap of a gas centrifuge enrichment plant. While very successful in reducing the hazards of uranium hexafluoride sample, the method still takes a considerable amount of time and can only be used in facilities where the apparatus has been installed; this arrangement generally prohibits the sampling of filled cylinders that have already exited the facility and have been deposited in the on-site tank storage yard. The handheld unit under development will allow the use of the Cristallini method at facilities that have not been converted as well as tanks in the storage yard. The handheld system utilizes an active vacuum system, rather than a passive vacuum system in the facility setup, to drive the uranium hexafluoride onto the adsorbing media. The handheld unit will be battery operated for fully autonomous operation and will include onboard pressure sensing and flushing capability. To date, the system concept of operations was demonstrated with tungsten hexafluoride that showed the active vacuum pump with multiple cartridges of adsorbing media was viable. Concurrently, the hardened prototype system was developed and tested; removable sample cartridges were developed (the only non-COTS component to date); and preparations were made for uranium tests and a domestic field test.

Including environmental concerns in management strategies for depleted uranium hexafluoride

International Nuclear Information System (INIS)

Goldberg, M.; Avci, H.I.; Bradley, C.E.

1995-01-01

One of the major programs within the Office of Nuclear Energy, Science, and Technology of the US Department of Energy (DOE) is the depleted uranium hexafluoride (DUF 6 ) management program. The program is intended to find a long-term management strategy for the DUF 6 that is currently stored in approximately 46,400 cylinders at Paducah, KY; Portsmouth, OH; and Oak Ridge, TN, USA. The program has four major components: technology assessment, engineering analysis, cost analysis, and the environmental impact statement (EIS). From the beginning of the program, the DOE has incorporated the environmental considerations into the process of strategy selection. Currently, the DOE has no preferred alternative. The results of the environmental impacts assessment from the EIS, as well as the results from the other components of the program, will be factored into the strategy selection process. In addition to the DOE's current management plan, other alternatives continued storage, reuse, or disposal of depleted uranium, will be considered in the EIS. The EIS is expected to be completed and issued in its final form in the fall of 1997

A Radiation-Triggered Surveillance System for UF6 Cylinder Monitoring

Energy Technology Data Exchange (ETDEWEB)

Curtis, Michael M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Myjak, Mitchell J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2016-09-23

This report provides background information and representative scenarios for testing a prototype radiation-triggered surveillance system at an operating facility that handles uranium hexafluoride (UF₆) cylinders. The safeguards objective is to trigger cameras using radiation, or radiation and motion, rather than motion alone, to reduce significantly the number of image files generated by a motion-triggered system. The authors recommend the use of radiation-triggered surveillance at all facilities where cylinder paths are heavily traversed by personnel. The International Atomic Energy Agency (IAEA) has begun using surveillance cameras in the feed and withdrawal areas of gas centrifuge enrichment plants (GCEPs). The cameras generate imagery using elapsed time or motion, but this creates problems in areas occupied 24/7 by personnel. Either motion-or-interval-based triggering generates thousands of review files over the course of a month. Since inspectors must review the files to verify operator material-flow-declarations, a plethora of files significantly extends the review process. The primary advantage of radiation-triggered surveillance is the opportunity to obtain full-time cylinder throughput verification versus what presently amounts to part-time verification. Cost savings should be substantial, as the IAEA presently uses frequent unannounced inspections to verify cylinder-throughput declarations. The use of radiation-triggered surveillance allows the IAEA to implement less frequent unannounced inspections for the purpose of flow verification, but its principal advantage is significantly shorter and more effective inspector video reviews.

Chemical exchange between UF6 and UF6- ion in anhydrous hydrofluoric acid

International Nuclear Information System (INIS)

Chatelet, J.; Luce, M.; Plurien, P.; Rigny, P.

1975-01-01

The chemical exchange between UF 6 and the UF 6 - ion is of potential interest for the separation of U isotopes. In this paper, results concerning the value of the separation factor and the kinetics of the homogeneous exchange are given [fr

Uranium recovery from slags of metallic uranium

International Nuclear Information System (INIS)

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

2006-01-01

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

Development of an On-Line Uranium Enrichment Monitor

International Nuclear Information System (INIS)

Xuesheng, L.; Guorong, L.; Yonggang, Z.; Xueyuan, H. X.-Y.

2015-01-01

An on-line enrichment monitor was developed to measure the enrichment of UF6 flowing through the processing pipes in centrifuge uranium enrichment plant. A NaI(Tl) detector was used to measure the count rates of the 186 keV gamma ray emitted from 235U, and the total quantity of uranium was determined from thermodynamic characteristics of gaseous uranium hexafluoride. The results show that the maximum relative standard deviation is less than 1% when the measurement time is 120 s or more and the pressure is more than 2 kPa in the measurement chamber. There are two working models for the monitor. The monitor works normally in the continuous model, When the gas's pressure in the pipe fluctuates greatly, it can work in the intermittent model, and the measurement result is very well. The background of the monitor can be measured automatically periodically. It can control automatically electromagnetic valves open and close, so as to change the gas's quantity in the chamber. It is a kind of unattended and remote monitor, all of data can be transfer to central control room. It should be effective for nuclear materials accountability verifications and materials balance verification at uranium enrichment plant by using the monitor to monitor Uranium enrichment of gaseous uranium hexafluoride in the output end of cascade continuously. (author)

Hazard analysis in uranium hexafluoride production facility

International Nuclear Information System (INIS)

Marin, Maristhela Passoni de Araujo

1999-01-01

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)

Ningyo Toge uranium enrichment pilot plant comes into full

International Nuclear Information System (INIS)

1982-01-01

The uranium enrichment pilot plant of the Power Reactor and Nuclear Fuel Development Corporation at Ningyo Toge went into full operation on March 26, 1982. This signifies that the front end of the nuclear fuel cycle in Japan, from uranium ore to enrichment, is only a step away from commercialization. On the same day, the pilot plant of uranium processing and conversion to UF 6 , the direct purification of uranium ore into uranium hexafluoride, began batch operation at the same works. The construction of the uranium enrichment pilot plant has been advanced in three stages: i.e. OP-1A with 1000 centrifuges, OP-1B with 3000 centrifuges and OP-2 with 3000 centrifuges. With a total of 7000 centrifuges, the pilot plant, the first enrichment plant in Japan, has now a capacity of supplying enriched uranium for six months operation of a 1,000 MW nuclear power plant. (J.P.N.)

Development of a reduction process of ammonium uranyl carbonate to uranium dioxide in a fluidized bed

International Nuclear Information System (INIS)

Gomes, R.P.; Riella, H.G.

1990-07-01

Laboratory development of ammonium uranyl carbonate (AUC) reduction to uranium dioxide (UO 2 ) using fluidized bed furnace technique is described. The reaction is carried out at 500-550 0 C using hydrogen, liberated from cracking of ammonia, as a reducing agent. As the AUC used is obtained from uranium hexafluoride (UF 6 ) it contains considerable amount of fluoride (approx. 500μg/g) as contaminant. The presence of fluoride leads to high corrosion rates and hence the fluoride concentration is reduced by pyrohydrolisis of UO 2 . Physical and Chemical properties of the final product (UO 2 ) obtained were characterized. (author) [pt

Computational simulation studies of the reduction process of UF4 to metallic uranium

International Nuclear Information System (INIS)

Borges, Wesden de Almeida

2011-01-01

The production of metallic uranium is essential for production of fuel elements for using in nuclear reactors manufacturing of radioisotopes and radiopharmaceuticals. In IPEN, metallic uranium is produced by magnesiothermical reduction of UF 4 . This reaction is performed in a closed graphite crucible inserted in a sealed metal reactor and no contact with the outside environment. The set is gradually heated in an oven pit, until it reaches the ignition temperature of the reaction (between 600-650 degree C). The modeling of the heating profile of the system can be made using simulation programs by finite element method. Through the thermal profiles in the load, we can have a notion of heating period required for the reaction to occur, allowing the identification of the same group in a greater or smaller yield in metallic uranium production. Thermal properties of UF 4 are estimated, obtaining thermal conductivity and heat capacity using the Flash Laser Method, and for the load UF 4 + Mg, either. The results are compared to laboratory tests to simulate the primary production process. (author)

Development of uranium milling and conversion

International Nuclear Information System (INIS)

Takada, Shingo; Hirono, Shuichiro.

1983-11-01

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, UF 4 .1-1.2H 2 O (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 350 0 C in an inert gas flow. The complete conversion from UF 4 into UF 6 is achieved by a fluidized-bed reactor and a high value of utilization efficiency of fluorine, over 99.9 percent, is attained at about 400 0 C. (author)

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

International Nuclear Information System (INIS)

1983-01-01

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

Evaluation of tecniques for controlling UF6 release clouds in the GAT environmental chamber

International Nuclear Information System (INIS)

Lux, C.J.

1982-01-01

Studies designed to characterize the reaction between UF 6 and atmospheric moisture, evaluate environmental variables of UF 6 cloud formation and ultimate cloud fate, and UF 6 release cloud control procedure have been conducted in the 1200 cu. ft. GAT environmental chamber. In earlier chamber experiments, 30 separate UF 6 release tests indicated that variations of atmospheric conditions and sample sizes had no significant effect on UO 2 F 2 particle size distribution, release cloud formation, or cloud settling rates. During the past year, numerous procedures have been evaluated for accelerating UF 6 cloud knockdown in a series of 37 environmental chamber releases. Knockdown procedures included: coarse water spray; air jet; steam spray (electrostatically charged and uncharged); carbon dioxide; Freon-12; fine water mist (uncharged); boric acid mist (charged and uncharged); and an ionized dry air stream. UF 6 hydrolysis cloud settling rates monitored by a laser/powermeter densitometer, indicated the relative effectiveness of various cloud knockdown techniques. Electrostatically charged boric acid/water mist, and electrostatically ionized dry air were both found to be very effective, knocking down the UO 2 F 2 release cloud particles in two to five minutes. Work to adapt these knockdown techniques for use under field conditions is continuing, taking into account recovery of the released uranium as well as nuclear criticality constraints

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

International Nuclear Information System (INIS)

Jones, E

1999-01-01

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

Global Monitoring Of Uranium Hexifloride Cylinders Next Steps In Development Of An Action Plan

International Nuclear Information System (INIS)

Hanks, D.

2010-01-01

Over 40 industrial facilities world-wide use standardized uranium hexafluoride (UF 6 ) cylinders for transport, storage and in-process receiving in support of uranium conversion, enrichment and fuel fabrication processes. UF 6 is processed and stored in the cylinders, with over 50,000 tU of UF 6 transported each year in these International Organization for Standardization (ISO) qualified containers. Although each cylinder is manufactured to an ISO standard that calls for a nameplate with the manufacturer's identification number (ID) and the owner's serial number engraved on it, these can be quite small and difficult to read. Recognizing that each facility seems to use a different ID, a cylinder can have several different numbers recorded on it by means of metal plates, sticky labels, paint or even marker pen as it travels among facilities around the world. The idea of monitoring movements of UF 6 cylinders throughout the global uranium fuel cycle has become a significant issue among industrial and safeguarding stakeholders. Global monitoring would provide the locations, movements, and uses of cylinders in commercial nuclear transport around the world, improving the efficiency of industrial operations while increasing the assurance that growing nuclear commerce does not result in the loss or misuse of cylinders. It should be noted that a unique ID (UID) attached to a cylinder in a verifiable manner is necessary for safeguarding needs and ensuring positive ID, but not sufficient for an effective global monitoring system. Modern technologies for tracking and inventory control can pair the UID with sensors and secure data storage for content information and complete continuity of knowledge over the cylinder. This paper will describe how the next steps in development of an action plan for employing a global UF 6 cylinder monitoring network could be cultivated using four primary UID functions - identification, tracking, controlling, and accounting.

The Determination of Uranium and Trace Metal Impurities in Yellow Cake Sample by Chemical Method

International Nuclear Information System (INIS)

Busamongkol, Arporn; Rodthongkom, Chouvana

1999-01-01

The purity of uranium cake is very critical in nuclear-grade uranium (UO 2 ) and uranium hexafluoride (UF 6 ) production. The major element in yellow cake is uranium and trace metal impurities. The objective of this study is to determine uranium and 25 trace metal impurities; Aluminum, Barium, Bismuth, Calcium, Cadmium, Cobalt, Chromium, Copper, Iron, Potassium, Iithium, Magnesium, Manganese, Molybdenum, Sodium, Niobium, Nickel, Lead, Antimony, Tin, Strontium, Titanium, Vanadium, Zinc and Zirconium, Uranium is determined by Potassium dichromate titration, after solvent extraction with Cupferon in Chloroform, Trace metal impurities are determined by solvent extraction with Tributyl Phosphate in Carbon-tetrachloride ( for first 23 elements) and N-Benzoyl-N-Phenylhydroxylamine in Chloroform ( for last 2 elements), then analyzed by Atomic Absorption Spectrophotometer (AAS) compared with Inductively Couple Plasma Spectrophotometers (ICP). The accuracy and precision are studied with standard uranium octaoxide

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

International Nuclear Information System (INIS)

Miles, T.L.; Liu, Y.

1995-08-01

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

A system for the synthesis of uranium hexafluoride by high pressure fluorination of uranium oxides

International Nuclear Information System (INIS)

Elizalde T, J.; Saniger B, J.M.; Nava S, R.

1986-01-01

An equipment for the synthesis of uranium hexafluoride by a direct fluorination method is reported. The equipment is composed by a gaseous fluorine supply, a gas burette, a reactor tube inside a protective shield, a soda-lime chemical trap and a vacuum system. The fluorination is accomplished at a pressure of about 70 kg/cm 2 (1000 lb in 2 ), using gaseous fluorine. (Author). 5 refs, 4 figs, 2 tabs

Laboratory and pilot-plant studies on the conversion of uranyl nitrate hexahydrate to UF6 by fluidized-bed processes

International Nuclear Information System (INIS)

Youngblood, E.L.; Urza, I.J.; Cathers, G.I.

1977-06-01

This report describes laboratory and pilot-plant studies on the conversion of uranyl nitrate hexahydrate (UNH) to UF 6 and on purification of the UF 6 . Experimental laboratory studies on the removal of residual nitrate from uranium trioxide (UO 3 ) calcine and the fluorination of technetium and subsequent sorption on MgF 2 were conducted to support the pilot-plant work. Two engineering-scale pilot plants utilizing fluidized-bed processes were constructed for equipment and process testing of the calcination of UNH to UO 3 and the direct fluorination of UO 3 to UF 6

Action of the chlorine trifluoride on water vapour. Analysis of reaction products. Technical report - 589

International Nuclear Information System (INIS)

Bougon, R.

1961-06-01

As the separation of uranium 235 from uranium 238 by gaseous diffusion under the form of uranium hexa-fluoride requires the use of materials which may contain some impurities retained by chemical or physical bounds, this report addresses the use of a reactant which would allow these impurities to be removed. Due to its properties (inert with respect to UF 6 ; transforms most of impurities into volatile compounds, and different UF compounds into UF 6 ; strongly reacts on water; all its degradation products are volatile), chlorine trifluoride (ClF 3 ) has been chosen. It is used for the preprocessing of materials for their passivation with respect to UF 6 , and for a post-processing for the regeneration of porous materials by transformation of UF 4 , UO 2 F 2 and UF x into UF 6 . The authors more particularly studied the reaction between ClF 3 and water

Actual and Idealized Crystal Field Parameterizations for the Uranium Ions in UF 4

Science.gov (United States)

Gajek, Z.; Mulak, J.; Krupa, J. C.

1993-12-01

The crystal field parameters for the actual coordination symmetries of the uranium ions in UF 4, C2 and C1, and for their idealizations to D2, C2 v , D4, D4 d , and the Archimedean antiprism point symmetries are given. They have been calculated by means of both the perturbative ab initio model and the angular overlap model and are referenced to the recent results fitted by Carnall's group. The equivalency of some different sets of parameters has been verified with the standardization procedure. The adequacy of several idealized approaches has been tested by comparison of the corresponding splitting patterns of the 3H 4 ground state. Our results support the parameterization given by Carnall. Furthermore, the parameterization of the crystal field potential and the splitting diagram for the symmetryless uranium ion U( C1) are given. Having at our disposal the crystal field splittings for the two kinds of uranium ions in UF 4, U( C2) and U( C1), we calculate the model plots of the paramagnetic susceptibility χ( T) and the magnetic entropy associated with the Schottky anomaly Δ S( T) for UF 4.

On the applicability of the critical safety function concept to a uranium hexafluoride conversion unit

International Nuclear Information System (INIS)

Santos, F.C.; Goncalves, J.S.; Melo, P.F. Frutuoso e; Medeiros, J.A.C.C.

2013-01-01

This paper presents a discussion on the applicability on the critical safety function (CSF) concept as a design criterion for the new UF 6 conversion plant of Industrias Nucleares do Brazil (INB). This discussion is in the context of accident management, under the safety function oriented management. Safety functions may be understood as those whose loss may lead to releases of radioactive material or highly toxic chemicals, having possible radiological and/or occupational consequences for workers, the public or the environment. They should be designed to prevent criticality and to ensure adequate process confinement, thus preventing radioactive material releases that might lead to internal or external exposure and highly toxic chemical releases and exposure. The main hazards is the potential release of chemicals, especially HF and UF 6 . A criticality hazard exists only if the conversion facility processes uranium with a 235 U concentration greater than 1% Industrial activities for UF 6 production include handling and processing explosive, toxic and lethal chemicals, such as HF, H 2 and elemental F 2 , besides intermediate compounds containing uranium. State trees and definition of logical arrangements to construct an annunciation system are the next development stages, resulting form the establishment of applicable CSFs as representative of the next development stages, resulting from the establishment of applicable CSFs as representative of the various systems that make up the conversion plant. Discussed also in the biggest challenge of the development of this innovation, that is, the uncertainties related to the impact of human factors (not subject to monitoring by sensors or process conventional instrumentation). (author)

235U enrichment determination on UF6 cylinders with CZT detectors

Science.gov (United States)

Berndt, Reinhard; Mortreau, Patricia

2018-04-01

Measurements of uranium enrichment in UF6 transit cylinders are an important nuclear safeguards verification task, which is performed using a non-destructive assay method, the traditional enrichment meter, which involves measuring the count rate of the 186 keV gamma ray. This provides a direct measure of the 235U enrichment. Measurements are typically performed using either high-resolution detectors (Germanium) with e-cooling and battery operation, or portable devices equipped with low resolution detectors (NaI). Despite good results being achieved when measuring Low Enriched Uranium in 30B type cylinders and natural uranium in 48Y type containers using both detector systems, there are situations, which preclude the use of one or both of these systems. The focus of this work is to address some of the recognized limitations in relation to the current use of the above detector systems by considering the feasibility of an inspection instrument for 235U enrichment measurements on UF6 cylinders using the compact and light Cadmium Zinc Telluride (CZT) detectors. In the present work, test measurements were carried out, under field conditions and on full-size objects, with different CZT detectors, in particular for situations where existing systems cannot be used e.g. for stacks of 48Y type containers with depleted uranium. The main result of this study shows that the CZT detectors, actually a cluster of four μCZT1500 micro spectrometers provide as good results as the germanium detector in the ORTEC Micro-trans SPEC HPGe Portable spectrometer, and most importantly in particular for natural and depleted uranium in 48Y cylinders.

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

International Nuclear Information System (INIS)

1994-11-01

This document includes a description of the physical, chemical and radiological properties of UF 6 and related products, including information concerning their production, handling, storage and transportation and the management of the wastes which result. All the operations of UF 6 management are considered form a safety point of view. The IAEA organized a series of meetings to consider the hazards of UF 6 transport since considerable quantities of depleted, natural and enriched UF 6 are transported between nuclear fuel sites. Storage of depleted UF 6 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 UF 6 handling, are included. The intention of this document is to provide analysis of the safety implications of all stages of UF 6 operations and to draw attention to specific features and properties of importance. 38 refs, figs, tabs

Determination of UO2F2, UO2 and UF4 in tetrafluoride of uranium samples

International Nuclear Information System (INIS)

Contreras Guzman, Ariel; Arlegui Hormazabal, Oscar

2003-01-01

The combustible elements for investigation reactors that at the present are manufacturing by the Chilean Nuclear Energy Commission (CCHEN) they are based on aluminum and silicide uranium powdered which is obtained from metallic uranium. At the present the Conversion Units, is developing the technology of transformation UF 6 in metallic Uranium, reason for which is necessary that the Chemical Analysis Laboratory have a methodology that allows to quantify the presence of UO 2 F 2 , UO 2 and UF 4 in the samples obtained in this transformation process. For this reason we are implements the methodology of sequential analysis that had been developed previously, for the Institute of Energy and Nuclear Investigations, IPEN Brasil, and to adapt it to the present conditions in the Laboratory of Chemical Analysis of the CCHEN. This method is based on the different solubilities that present those sample in front of solvents as ethanol and solutions of ammonium oxalate, what allows the separation of these compounds for a later analysis by means of the method of Davies and Gray. This method is based on the reduction of the uranium (VI) to uranium (IV) with ferrous ion amid phosphoric acid, quantifying the present uranium in the samples by means of titration with potassium dicromate. With the purpose of checking the efficiency of the method, the sum of all values of uranium coming from each compound and compares it with the total uranium of the sample (author)

Technical documentation of HGSYSTEM/UF6 model

International Nuclear Information System (INIS)

Hanna, S.R.; Chang, J.C.; Zhang, J.X.

1996-01-01

MMES has been directed to upgrade the safety analyses for the gaseous diffusion plants at Paducah KY and Piketon OH. These will require assessment of consequences of accidental releases of UF 6 to the atmosphere at these plants. The HGSYSTEM model has been chosen as the basis for evaluating UF 6 releases; it includes dispersion algorithms for dense gases and treats the chemistry and thermodynamics of HF, a major product of the reaction of UF 6 with water vapor in air. Objective of this project was to incorporate additional capability into HGSYSTEM: UF 6 chemistry and thermodynamics, plume lift-off algorithms, and wet and dry deposition. The HGSYSTEM modules are discussed. The hybrid HGSYSTEM/UF 6 model has been evaluated in three ways

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

Energy Technology Data Exchange (ETDEWEB)

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

1987-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

NONE

1994-11-01

This document includes a description of the physical, chemical and radiological properties of UF{sub 6} and related products, including information concerning their production, handling, storage and transportation and the management of the wastes which result. All the operations of UF{sub 6} management are considered form a safety point of view. The IAEA organized a series of meetings to consider the hazards of UF{sub 6} transport since considerable quantities of depleted, natural and enriched UF{sub 6} are transported between nuclear fuel sites. Storage of depleted UF{sub 6} 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 UF{sub 6} handling, are included. The intention of this document is to provide analysis of the safety implications of all stages of UF{sub 6} operations and to draw attention to specific features and properties of importance. 38 refs, figs, tabs.

Process and system for isotope separation using the selective vibrational excitation of molecules

International Nuclear Information System (INIS)

Woodroffe, J.A.; Keck, J.C.

1976-01-01

This invention concerns the separation of isotopes by using the isotopically selective vibrational excitation and the vibration-translation reactions of the excited particles. UF 6 molecular mixed with a carrier gas, such as argon, are directed through a refrigerated chamber lighted by a laser radiation tuned to excite vibrationally the uranium hexafluoride molecules of a particular uranium isotope. The density of the carrier gas is preferably maintained above the density of the uranium hexafluoride to allow a greater collision probability of the vibrationally excited molecules with a carried molecule. In such a case, the vibrationally excited uranium hexafluoride will collide with a carrier gas molecule provoking the conversion of the excitation energy into a translation of the excited molecule, resulting in thermal energy or greater diffusibility than that of the other uranium hexafluoride molecules [fr

Photochemical removal of NpF6 and PuF6 from UF6 gas streams

International Nuclear Information System (INIS)

Beitz, J.V.; Williams, C.W.

1990-01-01

A novel photochemical method of removing reactive fluorides from UF 6 gas has been discovered. This method reduces generated waste to little more than the volume of the removed impurities, minimizes loss of UF 6 , and can produce a recyclable by-product, fluorine gas. In our new method, impure UF 6 , is exposed to ultraviolet light which dissociates the UF 6 to UF 5 and fluorine atom. Impurities which chemically react with UF 5 are reduced and form solid compounds easily removed from the gas while UF 5 is converted back to UF 6 . Proof-of-concept testing involved UF 6 containing NpF 6 and PuF 6 with CO added as a fluorine atom scavenger. In a single photolysis step, greater than 5000-fold reduction of PuF 6 was demonstrated while reducing NpF 6 by more than 40-fold. This process is likely to remove corrosion and fission product fluorides that are more reactive than UF 6 and has been demonstrated without an added fluorine atom scavenger by periodically removing photogenerated fluorine gas. 44 refs., 3 figs., 2 tabs

Action of the chlorine trifluoride on water vapour. Analysis of reaction products. Technical report - 589; Action du trifluorure de chlore sur la vapeur d'eau. Analyses des produits de reaction. Rapport technique - 589

Energy Technology Data Exchange (ETDEWEB)

Bougon, R.

1961-06-15

As the separation of uranium 235 from uranium 238 by gaseous diffusion under the form of uranium hexa-fluoride requires the use of materials which may contain some impurities retained by chemical or physical bounds, this report addresses the use of a reactant which would allow these impurities to be removed. Due to its properties (inert with respect to UF{sub 6}; transforms most of impurities into volatile compounds, and different UF compounds into UF{sub 6}; strongly reacts on water; all its degradation products are volatile), chlorine trifluoride (ClF{sub 3}) has been chosen. It is used for the preprocessing of materials for their passivation with respect to UF{sub 6}, and for a post-processing for the regeneration of porous materials by transformation of UF{sub 4}, UO{sub 2}F{sub 2} and UF{sub x} into UF{sub 6}. The authors more particularly studied the reaction between ClF{sub 3} and water.

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...

Environmental impact appraisal for renewal of source material license No. SUB-526 (Docket No. 40-3392)

International Nuclear Information System (INIS)

1984-05-01

Allied Chemical Company operates a privately owned UF 6 production facility at Metropolis, Illinois, At this facility, uranium ore concentrates are converted into uranium hexafluoride (UF 6 ). The UF 6 product from this facility is shipped to Department of Energy (DOE) gaseous diffusion plants for enrichment of the 235 U isotope. This assessment: (1) reviews the operation of the facility during the recent license period by comparing the plant effluent releases or environmental monitoring data with permissible levels of contaminants; and (2) determines the impact on the environment from continued operation of the facility in its current configuration. 10 figures, 44 tables

On the applicability of the critical safety function concept to a uranium hexafluoride conversion unit

Energy Technology Data Exchange (ETDEWEB)

Santos, F.C.; Goncalves, J.S.; Melo, P.F. Frutuoso e; Medeiros, J.A.C.C., E-mail: fcruz@nuclear.ufrj.br, E-mail: jsgoncalves@inb.gov.br, E-mail: frutuoso@nuclear.ufrj.br, E-mail: canedo@imp.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil)

2013-07-01

This paper presents a discussion on the applicability on the critical safety function (CSF) concept as a design criterion for the new UF{sub 6} conversion plant of Industrias Nucleares do Brazil (INB). This discussion is in the context of accident management, under the safety function oriented management. Safety functions may be understood as those whose loss may lead to releases of radioactive material or highly toxic chemicals, having possible radiological and/or occupational consequences for workers, the public or the environment. They should be designed to prevent criticality and to ensure adequate process confinement, thus preventing radioactive material releases that might lead to internal or external exposure and highly toxic chemical releases and exposure. The main hazards is the potential release of chemicals, especially HF and UF{sub 6}. A criticality hazard exists only if the conversion facility processes uranium with a {sup 235}U concentration greater than 1% Industrial activities for UF{sub 6} production include handling and processing explosive, toxic and lethal chemicals, such as HF, H{sub 2} and elemental F{sub 2}, besides intermediate compounds containing uranium. State trees and definition of logical arrangements to construct an annunciation system are the next development stages, resulting form the establishment of applicable CSFs as representative of the next development stages, resulting from the establishment of applicable CSFs as representative of the various systems that make up the conversion plant. Discussed also in the biggest challenge of the development of this innovation, that is, the uncertainties related to the impact of human factors (not subject to monitoring by sensors or process conventional instrumentation). (author)

Observation of inner surface of flame-tower type reactor for uranium conversion

International Nuclear Information System (INIS)

Amamoto, Ippei; Terai, Takayuki; Umetsu, Hiroshi

2003-01-01

A fluorination reactor, which has been used to convert uranium tetrafluoride (UF 4 ) into uranium hexafluoride (UF 6 ), was completed after approximately 6000 hours operation at the uranium conversion facility in Japan. The observation of its inner surface was carried out to understand its corrosive condition and mechanism. The main wall of the reactor is made of Monel Alloy and its operational temperature is approximately 450degC at external surface under gaseous fluorine atmosphere. A sampling was undertaken from the most corrosive part of the reactor wall, and its analysis was carried out to obtain the data for the condition of appearance, thickness, macro and micro structure, etc. The results of observation are as follows: (1) The thickness decreased evenly (average 3.9 mm/year); (2) The chemical composition of corrosive products as coating was mainly nickel fluoride (NiF 2 ), which suggested that the corrosion mechanism could have been caused by the high temperature gas corrosion; (3) The total amount of coating was lower than that of a loss in thickness. For some reason, some of coating would seem to become extinct on the surface of the wall. The deterioration of coating, which formed a protector on the wall due to excess heating of the wall, the sand erosion effect by UF 4 , etc. have contributed to this state of condition. (author)

Moderation control in low enriched 235U uranium hexafluoride packaging operations and transportation

International Nuclear Information System (INIS)

Dyer, R.H.; Kovac, F.M.; Pryor, W.A.

1993-01-01

Moderation control is the basic parameter for ensuring nuclear criticality safety during the packaging and transport of low 235 U enriched uranium hexafluoride before its conversion to nuclear power reactor fuel. Moderation control has permitted the shipment of bulk quantities in large cylinders instead of in many smaller cylinders and, therefore, has resulted in economies without compromising safety. Overall safety and uranium accountability have been enhanced through the use of the moderation control. This paper discusses moderation control and the operating procedures to ensure that moderation control is maintained during packaging operations and transportation

Laboratory and pilot-plant studies on the conversion of uranyl nitrate hexahydrate to UF/sub 6/ by fluidized-bed processes

Energy Technology Data Exchange (ETDEWEB)

Youngblood, E.L.; Urza, I.J.; Cathers, G.I.

1977-06-01

This report describes laboratory and pilot-plant studies on the conversion of uranyl nitrate hexahydrate (UNH) to UF/sub 6/ and on purification of the UF/sub 6/. Experimental laboratory studies on the removal of residual nitrate from uranium trioxide (UO/sub 3/) calcine and the fluorination of technetium and subsequent sorption on MgF/sub 2/ were conducted to support the pilot-plant work. Two engineering-scale pilot plants utilizing fluidized-bed processes were constructed for equipment and process testing of the calcination of UNH to UO/sub 3/ and the direct fluorination of UO/sub 3/ to UF/sub 6/.

Investigation of UF6 behavior in a fire

International Nuclear Information System (INIS)

Williams, W.R.

1988-01-01

Reactions between UF 6 and combustible gases and the potential for UF 6 -filled cylinders to rupture when exposed to fire are addressed. Although the absence of kinetic data prevents specific identification and quantification of the chemical species formed, potential reaction products resulting from the release of UF 6 into a fire include UF 4 , UO 2 F 2 , HF, C, CF 4 ,COF 2 , and short chain, fluorinated or partially fluorinated hydrocarbons. Such a release adds energy to a fire relative to normal combustion reactions. Time intervals to an assumed point of rupture for UF 6 -filled cylinders exposed to fire are estimated conservatively. Several related studies are also summarized, including a test series in which small UF 6 -filled cylinders were immersed in fire resulting in valve failures and explosive ruptures. It is concluded that all sizes of UF 6 cylinders currently in use may rupture within 30 minutes when totally immersed in a fire. For cylinders adjacent to fires, rupture of the larger cylinders appears much less likely

UF{sub 6} pressure excursions during cylinder heating

Energy Technology Data Exchange (ETDEWEB)

Brown, P.G. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

1991-12-31

As liquid UF{sub 6} inside a cylinder changes from a liquid to a solid, it forms a porous solid which occupies approximately the same volume as that of the liquid before cooling. Simultaneously as the liquid cools, UF{sub 6} vapor in the cylinder ullage above the liquid desublimes on the upper region of the inner cylinder wall. This solid is a dense, glass-like material which can accumulate to a significant thickness. The thickness of the solid coating on the upper cylinder wall and directly behind the cylinder valve area will vary depending on the conditions during the cooling stage. The amount of time lapsed between UF{sub 6} solidification and UF{sub 6} liquefaction can also affect the UF{sub 6} coating. This is due to the daily ambient heat cycle causing the coating to sublime from the cylinder wall to cooler areas, thus decreasing the thickness. Structural weakening of the dense UF{sub 6} layer also occurs due to cylinder transport vibration and thermal expansion. During cylinder heating, the UF{sub 6} nearest the cylinder wall will liquefy first. As the solid coating behind the cylinder valve begins to liquefy, it results in increased pressure depending upon the available volume for expansion. At the Paducah Gaseous Diffusion Plant (PGDP) during the liquefaction of the UF{sub 6} in cylinders in the UF{sub 6} feed and sampling autoclaves, this pressure increase has resulted in the activation of the systems rupture discs which are rated at 100 pounds per square inch differential.

Sampling and characterization of aerosols formed in the atmospheric hydrolysis of UF6

International Nuclear Information System (INIS)

Bostick, W.D.; McCulla, W.H.; Pickrell, P.W.; Branam, D.A.

1983-01-01

When gaseous UF 6 is released into the atmosphere, it rapidly reacts with ambient moisture to form an aerosol of uranyl fluoride and HF. As part of our Safety Analysis program, we have performed several experimental releases of UF 6 (from natural uranium) in contained volumes in order to investigate techniques for sampling and characterizing the aerosol materials. The aggregrate particle morphology and size distribution have been found to be dependent upon several conditions, including the relative humidity at the time of the release and the elapse time after the release. Aerosol composition and settling rate have been investigated using isokinetic samplers for the separate collection of UO 2 F 2 and HF, and via laser spectroscopic remote sensing (Mie scatter and infrared spectroscopy). 8 references

Performance studies on hydrofluoric acid fumes scrubbing systems

Energy Technology Data Exchange (ETDEWEB)

Sarkar, S; Bhowmik, A; Bera, T K; Sridhar, H; Shanmugavelu, P; Muralidhara, H R [Rare Materials Project, Bhabha Atomic Research Centre, Mysore (India)

1994-06-01

Uranium hexafluoride gas is a major process medium for the production of nuclear fuels. Different types of scrubbers suitable for disposal of exhaust gases containing low concentration of HF/UF{sub 6} contaminants, treatment of contaminated air from the working environment of a plant and bulk quantity of HF/UF{sub 6} from storage vessels are described. 8 refs., 3 figs., 3 tabs.

UV dissociation of vibrationally excited UF6

International Nuclear Information System (INIS)

Alexandre, M.; Clerc, M.; Gagnon, R.; Gilbert, M.; Isnard, P.; Nectoux, P.; Rigny, P.; Weulersse, J.M.

1983-01-01

Before application of laser photodissociation of UF 6 to the separation of uranium isotopes becomes practical, isotopic selectivity should be optimized. We present here results on the cross sections involved in the irradiation of UF 6 simultaneously with infrared and ultraviolet lasers, as a function of wavelengths, fluence and temperature (at 293 K and 105 K, in an adiabatic expansion). The experiment uses a Nd 3+ YAG pumped lithium niobate optical parametric oscillator as a tunable 16 μ light source. Energies of the order of 1 mJ can be obtained with linewidths smaller than 0.1 cm - . The UV source used is based on ND 3+ YAG pumped dye laser and various frequency mixing schemes. At low temperature the frequency variation of the absorbed infrared energy per molecule depends markedly on the IR fluence phisub(IR) with a maximum value varying as phisub(IR)sup(-1/2) and a frequency extension far beyond the low level absorption spectrum. The absorbed vibrational energy leads to a change in the UV cross section comparable with the effect of a rise in temperature. Using this a model is put forward to express the isotopic selectivity 235 U/ 238 U as a function of UV wavelength and IR irradiation conditions. Experimental results agree with this model, and yield to maximum selectivity close to two [fr

GLOBAL MONITORING OF URANIUM HEXIFLORIDE CYLINDERS NEXT STEPS IN DEVELOPMENT OF AN ACTION PLAN

Energy Technology Data Exchange (ETDEWEB)

Hanks, D.

2010-06-09

Over 40 industrial facilities world-wide use standardized uranium hexafluoride (UF{sub 6}) cylinders for transport, storage and in-process receiving in support of uranium conversion, enrichment and fuel fabrication processes. UF{sub 6} is processed and stored in the cylinders, with over 50,000 tU of UF{sub 6} transported each year in these International Organization for Standardization (ISO) qualified containers. Although each cylinder is manufactured to an ISO standard that calls for a nameplate with the manufacturer's identification number (ID) and the owner's serial number engraved on it, these can be quite small and difficult to read. Recognizing that each facility seems to use a different ID, a cylinder can have several different numbers recorded on it by means of metal plates, sticky labels, paint or even marker pen as it travels among facilities around the world. The idea of monitoring movements of UF{sub 6} cylinders throughout the global uranium fuel cycle has become a significant issue among industrial and safeguarding stakeholders. Global monitoring would provide the locations, movements, and uses of cylinders in commercial nuclear transport around the world, improving the efficiency of industrial operations while increasing the assurance that growing nuclear commerce does not result in the loss or misuse of cylinders. It should be noted that a unique ID (UID) attached to a cylinder in a verifiable manner is necessary for safeguarding needs and ensuring positive ID, but not sufficient for an effective global monitoring system. Modern technologies for tracking and inventory control can pair the UID with sensors and secure data storage for content information and complete continuity of knowledge over the cylinder. This paper will describe how the next steps in development of an action plan for employing a global UF{sub 6} cylinder monitoring network could be cultivated using four primary UID functions - identification, tracking, controlling, and

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)

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

International Nuclear Information System (INIS)

Strunk, W.D.; Thornton, S.G.

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

75 FR 12738 - Proposed Subsequent Arrangement

Science.gov (United States)

2010-03-17

... the retransfer of 302,188 kg of U.S.-origin natural uranium trioxide (UO3) (82.73% U), 250,000 kg of which is uranium, from Cameco in Saskatoon, Saskatchewan, Canada to Springfields Fuels Ltd. in... transferred to Springfields Fuels Ltd. for conversion to uranium hexafluoride (UF6) for ultimate end use in a...

UF{sub 6} cylinder fire test

Energy Technology Data Exchange (ETDEWEB)

Park, S.H. [Oak Ridge K-25 Site, Oak Ridge, TN (United States)

1991-12-31

With the increasing number of nuclear reactors for power generation, there is a comparable increase in the amount of UF{sub 6} being transported. Likewise, the probability of having an accident involving UF{sub 6}-filled cylinders also increases. Accident scenarios which have been difficult to assess are those involving a filled UF{sub 6} cylinder subjected to fire. A study is underway at the Oak Ridge K-25 Site, as part of the US DOE Enrichment Program, to provide empirical data and a computer model that can be used to evaluate various cylinder-in-fire scenarios. It is expected that the results will provide information leading to better handling of possible fire accidents as well as show whether changes should be made to provide different physical protection during shipment. The computer model being developed will be capable of predicting the rupture of various cylinder sizes and designs as well as the amount of UF{sub 6}, its distribution in the cylinder, and the conditions of the fire.

Process for uranium separation and preparation of UO4.2NH3.2HF

International Nuclear Information System (INIS)

Dokuzoguz, H.Z.

1976-01-01

A process for treating the aqueous effluents that are produced in converting gaseous UF 6 (uranium hexafluoride) into solid UO 2 (uranium dioxide) by way of an intermediate (NH 4 ) 4 UO 2 (CO 3 ) 3 (''AUC'' Compound) is disclosed. These effluents, which contain large amounts of NH 4 + , CO 3 2- , F - , and a small amount of U are mixed with H 2 SO 4 (sulfuric acid) in order to expel CO 2 (carbon dioxide) and thereby reduce the carbonate concentration. The uranium is precipitated through treatment with H 2 O 2 (hydrogen peroxide) and the fluoride is easily recovered in the form of CaF 2 (calcium fluoride) by contacting the process liquid with CaO (calcium oxide). The presence of SO 4 2- (sulfate) in the process liquid during CaO contacting seems to prevent the development of a difficult-to-filter colloid. The process also provides for NH 3 recovery and recycling. Liquids discharged from the process, moreover, are essentially free of environmental pollutants. The waste treatment products, i.e., CO 2 , NH 3 , and U are economically recovered and recycled back into the UF 6 → UO 2 conversion process. The process, moreover, recovers the uranium as a precipitate in the second stage. This precipitate is a new inorganic chemical compound UO 4 .2NH 3 .2HF [uranyl peroxide-2-ammonia-2-(hydrogen fluoride)

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)

2002-04-01

This standard document describes the mode of operation of three different methods for the quantitative dosimetry of uranium in solutions, in UF 6 and in solids: reduction by iron (II), oxidation by potassium bi-chromate and titration. (J.S.)

Recent measurements concerning uranium hexafluoride-electron collision processes

International Nuclear Information System (INIS)

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

1976-01-01

Scattering of electrons by UF 6 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 UF 6 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

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

International Nuclear Information System (INIS)

Xu Heqing; Qiu Lufu

1987-01-01

The reduction of UF 6 to UF 4 by CCl 4 in a 0.08 m diameter vertical glass reactor has been studied. In the tests, UF 6 and CCl 4 , 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 UF 6 is essentially complete if a CCl 4 excess is maintained. The method is considered to be an effective process to meet continuous conversion of slightly enriched UF 6

UF6 reconversion experience by means of Sumitomo ADU process at JCO

International Nuclear Information System (INIS)

Ogawa, H.; Yamazaki, N.

1994-01-01

Since 1973, Japan Nuclear Fuel Conversion Co., Ltd. (JCO), a leading company in Japan on nuclear fuel manufacturing, has been involved in UF 6 reconversion to ceramic grade uranium dioxide (UO 2 ) for LWR fuel by means of the original ADU process developed by Sumitomo Metal Mining Co., Ltd.. This paper deals with the details of the Sumitomo ADU process as well as the performance results of it, especially from the standpoint of product quality

Formation of actinide hexafluorides at ambient temperatures with krypton difluoride

International Nuclear Information System (INIS)

Asprey, L.B.; Eller, P.G.; Kinkead, S.A.

1986-01-01

A second low-temperature agent, krypton difluoride, for generating volatile plutonium hexafluoride is reported (dioxygen difluoride is the only other reported agent). Plutonium hexafluoride is formed at ambient or lower temperature by the treatment of various solid substrates with krypton difluoride. Volatilization of uranium and neptunium from solid substrates using gaseous krypton difluoride is also reported for the first time. The formation of actinide hexafluorides has been confirmed for the reaction of krypton difluoride in anhydrous HF with UO 2 and with uranium and neptunium fluorides at ambient temperatures. Treatment of americium dioxide with krypton difluoride did not yield americium hexafluoride under the conditions studied. 15 references, 2 figures

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.

Electrochemical separation of uranium in the molten system LiF-NaF-KF-UF4

Science.gov (United States)

Korenko, M.; Straka, M.; Szatmáry, L.; Ambrová, M.; Uhlíř, J.

2013-09-01

This article is focused on the electrochemical investigation (cyclic voltammetry and related studies) of possible reduction of U4+ ions to metal uranium in the molten system LiF-NaF-KF(eut.)-UF4 that can provide basis for the electrochemical extraction of uranium from molten salts. Two-step reduction mechanism for U4+ ions involving one electron exchange in soluble/soluble U4+/U3+ system and three electrons exchange in the second step were found on the nickel working electrode. Both steps were found to be reversible and diffusion controlled. Based on cyclic voltammetry, the diffusion coefficients of uranium ions at 530 °C were found to be D(U4+) = 1.64 × 10-5 cm2 s-1 and D(U3+) 1.76 × 10-5 cm2 s-1. Usage of the nickel spiral electrode for electrorefining of uranium showed fairly good feasibility of its extraction. However some oxidant present during the process of electrorefining caused that the solid deposits contained different uranium species such as UF3, UO2 and K3UO2F5.

The present state of laser isotope separation of uranium

International Nuclear Information System (INIS)

Tashiro, Hideo; Nemoto, Koshichi.

1994-01-01

As the methods of uranium enrichment, gas diffusion method and centrifugal separation method in which power consumption is less and the cost is low have been carried out. On the other hand, as the future technology, the research and development of laser isotope separation technology have been carried out. There are the atomic laser separation process in which the laser beam of visible light is irradiated to atomic state uranium and the molecular laser separation process in which far infrared laser beam is irradiated to uranium hexafluoride molecules. The atomic process is divided into three steps, that is, the processes of uranium evaporation, the reaction of uranium with laser beam and the recovery of enriched uranium. The principle of the laser separation is explained. The state of development of laser equipment and separation equipment is reported. The principle and the present state of development of the molecular separation process which consists of the cooling of UF 6 gas, the generation of high power 16 μm laser pulses and the collection of the reaction product are explained. The present state of both processes in foreign countries is reported. (K.I.)

Materials considerations for UF6 gas-core reactor. Interim report for preliminary design study

International Nuclear Information System (INIS)

Wagner, P.

1977-04-01

The limiting materials problem in a high-temperature UF 6 core reactor is the corrosion of the core containment vessel. The UF 6 , the lower fluorides of uranium, and the fluorine that exist at the anticipated reactor operating conditions (1000 K and about one atmosphere UF 6 ) are all corrosive. Because of this, the materials evaluation effort for this reactor design study has concentrated on the identification of a viable system for the containment vessel that meets both the materials and neutronic requirements. A study of the literature has revealed that the most promising corrosion-resistant candidates are Ni or Ni-Al alloys. One of the conclusions of this work is that the containment vessel use a nickel liner or clad since the use of Ni as a structural member is precluded by its relative blackness to thermal neutrons. Estimates of corrosion rates of Ni and Ni-Al alloys, the effects of the pressure and temperature of F 2 on the corrosion rates, calculated equilibrium gas compositions at reactor core operating conditions, suggested methods of fabrication, and recommendations for future research and development are included

Transport of Powders through Rotary Kilns: Experimental Study and Modelling

OpenAIRE

Debacq , Marie; Hartmann , Didier; Houzelot , Jean-Leon; Ablitzer , Denis

1999-01-01

International audience; During the nuclear fuel cycle, uranium as hexafluoride is enriched by means of gaseous-diffusion process. The depleted UF6 resulting from the isotope separation stage is converted into U3O8 to enable its safe storage (conversion carried out by COGEMA). The UF6 -> UO2 conversion is performed in four identical plants : UF6 is hydrolysed in the gaseous phase through a vertical reactor, then the UO2F2 powder formed is pyrohydrolysed into U3O8 powder through a lightly incli...

MITS Feed and Withdrawal Subsystem: operating procedures

International Nuclear Information System (INIS)

Brown, W.S.

1980-01-01

This procedure details the steps involved in filling two of the four MITS (Machine Interface Test System) Feed and Withdrawal subsystem main traps and the Sample/Inventory Make-up Pipette with uranium hexafluoride from the ''AS RECEIVED'' UF 6 supply

Laboratory-scale catalysis studies of uranium and plutonium fluorination reactions by solid metal-fluorides

International Nuclear Information System (INIS)

Hochel, R.C.

1984-03-01

Various catalysts were evaluated for their effect on the rate of fluorination of the tetrafluorides of uranium and plutonium to produce the hexafluorides. Results of this work show that CoF 3 and AgF 2 are more effective than NiF 2 for UF 4 fluorination, producing rate increases in the range of 150 to 300 compared to UF 4 and fluorine alone. The use of these three catalysts was also found effective in the fluorinations of PuO 2 /PuF 4 and pure PuF 4 . However, enhancements were less. NiF 2 produced the best increases which were 8.1 for PuO 2 /PuF 4 and 3.6 for PuF 4 . Experiments were conducted in a simple flow-loop. Even larger enhancements might be obtained with fluidized beds. Details of the apparatus, experiments, methods, and a discussion of results are presented

Neutron methods for measuring 235U content in UF6 gas

International Nuclear Information System (INIS)

Stromswold, D.C.; Peurrung, A.J.; Reeder, P.L.; Pappas, R.A.; Sunberg, D.S.

1996-10-01

In the United States and Russia, UF 6 gas streams of highly enriched uranium and lower enrichment uranium am being blended to reduce the stockpile of the highly enriched material. The resultant uranium is no longer useful for weapons, but is suitable as fuel for nuclear reactors. A method to verify the blending of high- and low-enrichment uranium was developed at Pacific Northwest National Laboratory (PNNL) for the U.S. Department of Energy, Office of Research and Development (NN-20). In the United States, blending occurs at the U.S. Department of Energy's Portsmouth Gaseous Diffusion Plant located near Portsmouth, Ohio. In Russia, the blending takes place at Novouralsk. The United States is purchasing the blended product produced in Russia in a program to reduce the availability of enriched uranium that can be used for weapons production. Monitoring the 235 U mass flux of the input stream having the highly enriched uranium will provide confidence that high-enrichment uranium is being consumed in the blending process, and monitoring the output stream will provide an on-line measure of the 235 U in the mixed product. The Portsmouth plant is a potential test facility for non-destructive technology to monitor blending. In addition, monitoring the blending at Portsmouth can support International Atomic Energy Agency activities on controlling and reducing enriched uranium stockpiles

Depleted uranium processing and fluorine extraction

International Nuclear Information System (INIS)

Laflin, S.T.

2010-01-01

Since the beginning of the nuclear era, there has never been a commercial solution for the large quantities of depleted uranium hexafluoride generated from uranium enrichment. In the United States alone, there is already in excess of 1.6 billion pounds (730 million kilograms) of DUF_6 currently stored. INIS is constructing a commercial uranium processing and fluorine extraction facility. The INIS facility will convert depleted uranium hexafluoride and use it as feed material for the patented Fluorine Extraction Process to produce high purity fluoride gases and anhydrous hydrofluoric acid. The project will provide an environmentally friendly and commercially viable solution for DUF_6 tails management. (author)

Environmental assessment for the purchase of Russian low enriched uranium derived from the dismantlement of nuclear weapons in the countries of the former Soviet Union

International Nuclear Information System (INIS)

1994-01-01

The United States is proposing to purchase from the Russian Federation low enriched uranium (LEU) derived from highly enriched uranium (HEU) resulting from the dismantlement of nuclear weapons in the countries of the former Soviet Union. The purchase would be accomplished through a proposed contract requiring the United States to purchase 15,250 metric tons (tonnes) of LEU (or 22,550 tonnes of UF 6 ) derived from blending 500 metric tones uranium (MTU) of HEU from nuclear warheads. The LEU would be in the form of uranium hexafluoride (UF 6 ) and would be converted from HEU in Russia. The United States Enrichment Corporation (USEC) is the entity proposing to undertake the contract for purchase, sale, and delivery of the LEU from the Russian Federation. The US Department of Energy (DOE) is negotiating the procedure for gaining confidence that the LEU is derived from HEU that is derived from dismantled nuclear weapons (referred to as ''transparency),'' and would administer the transparency measures for the contract. There are six environments that could potentially be affected by the proposed action; marine (ocean); US ports of entry; truck or rail transportation corridors; the Portsmouth GDP; the electric power industry; and the nuclear fuel cycle industry. These environmental impacts are discussed

Environmental assessment for the purchase of Russian low enriched uranium derived from the dismantlement of nuclear weapons in the countries of the former Soviet Union

Energy Technology Data Exchange (ETDEWEB)

1994-01-01

The United States is proposing to purchase from the Russian Federation low enriched uranium (LEU) derived from highly enriched uranium (HEU) resulting from the dismantlement of nuclear weapons in the countries of the former Soviet Union. The purchase would be accomplished through a proposed contract requiring the United States to purchase 15,250 metric tons (tonnes) of LEU (or 22,550 tonnes of UF{sub 6}) derived from blending 500 metric tones uranium (MTU) of HEU from nuclear warheads. The LEU would be in the form of uranium hexafluoride (UF{sub 6}) and would be converted from HEU in Russia. The United States Enrichment Corporation (USEC) is the entity proposing to undertake the contract for purchase, sale, and delivery of the LEU from the Russian Federation. The US Department of Energy (DOE) is negotiating the procedure for gaining confidence that the LEU is derived from HEU that is derived from dismantled nuclear weapons (referred to as ``transparency),`` and would administer the transparency measures for the contract. There are six environments that could potentially be affected by the proposed action; marine (ocean); US ports of entry; truck or rail transportation corridors; the Portsmouth GDP; the electric power industry; and the nuclear fuel cycle industry. These environmental impacts are discussed.

Overseas shipments of 48Y cylinders

Energy Technology Data Exchange (ETDEWEB)

Tanaka, R.T.; Furlan, A.S. [Cameco Corp., Port Hope, Ontario (Canada)

1991-12-31

This paper describes experiences with two incidents of overseas shipments of uranium hexafluoride (UF{sub 6}) cylinders. The first incident involved nine empty UF{sub 6} cylinders in enclosed sea containers. Three UF{sub 6} cylinders broke free from their tie-downs and damaged and contaminated several sea containers. This paper describes briefly how decontamination was carried out. The second incident involved a shipment of 14 full UF{sub 6} cylinders. Although the incident did not cause an accident, the potential hazard was significant. The investigation of the cause of the near accident is recounted. Recommendations to alleviate future similar incidents for both cases are presented.

Review of potential models for UF6 dispersion

International Nuclear Information System (INIS)

Sykes, R.I.; Lewellen, W.S.

1992-07-01

A survey of existing atmospheric dispersion models has been conducted to determine the most appropriate basis for the development of a model for predicting the consequences of an accidental UF 6 release. The model is required for safety analysis studies and should therefore be computationally efficient. The release of UF 6 involves a number of physical phenomena which make the situation more complicated than passive dispersion of a trace gas. The safety analysis must consider the density variations in the UF 6 cloud, which can be heavier or lighter than the ambient air. The release also involves rapid chemical reactions and associated heat release, which must be modeled. Other Department of Energy storage facilities require a dense gas prediction capability, so the model must be sufficiently general for use with a variety of release scenarios. The special problems associated with UF 6 make it unique, so there are very few models with existing capability for the problem. There are, however, a large number of dense gas dispersion models, some with relevant chemical reaction modeling, that could potentially form the basis of an advanced UF 6 model. We have examined a large selection of possible candidates, and selected 5 models for detailed consideration

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

International Nuclear Information System (INIS)

Ferrada, J.J.; Hightower, J.R.; Begovich, J.M.

2000-01-01

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

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.

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

International Nuclear Information System (INIS)

1981-01-01

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 UO 2 powder for CANDU reactor fuel and UF 6 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

Evaluation of environmental-control technologies for commercial nuclear fuel-conversion (UF6) facilities

International Nuclear Information System (INIS)

Perkins, B.L.

1982-10-01

At present in the United States, there are two commercial conversion facilities. These facilities process uranium concentrate into UF 6 for shipment to the enrichment facilities. One conversion facility uses a dry hydrofluor process, whereas the other facility uses a process known as the wet solvent extraction-fluorination process. Because of the different processes used in the two plants, waste characteristics, quantities, and treatment practices differ at each facility. Wastes and effluent streams contain impurities found in the concentrate (such as uranium daughters, vanadium, molybdenum, selenium, arsenic, and ammonia) and process chemicals used in the circuit (including fluorine, nitrogen, and hydrogen), as well as small quantities of uranium. Studies of suitable disposal options for the solid wastes and sludges generated at the facilities and the long-term effects of emissions to the ambient environment are needed. 30 figures, 34 tables

Urenco`s experience of UF{sub 6} handling

Energy Technology Data Exchange (ETDEWEB)

Saelmans, F. [Urenco Almelo (Netherlands); Scane, C. [Urenco Capenhurst (United Kingdom); Christofzik, J. [Urenco Gronau (Germany)

1991-12-31

Urenco operates enrichment plants at three sites, Almelo (Netherlands), Capenhurst (United Kingdom) and Gronau (Germany). Current installed separative work capacity is 2,500 tSWpa. Since 1971, when the first pilot plants were built, enrichment production has totalled 18,000 tSW. During this last 20 years over 3,500 48 containers of UF{sub 6} have been fed to the plants, over 3,700 30 containers have been filled with product and delivered successfully to Urenco`s customers worldwide and over 3,000 48 containers of depleted tails have been filled and have either been returned to customers or retained for long term storage on site. The paper gives a brief outline of Urenco`s experience in handling UF{sub 6}: the equipment and methods used in receiving, feeding, filling, blending, liquid sampling, storing, moving on site and despatching of UF{sub 6} containers. Some of the difficulties experienced with UF{sub 6} containers are appended.

Semiportable load-cell-based weighing system prototype of 18.14-metric-ton (20-ton) capacity for UF6 cylinder weight verifications: description and testing procedure

International Nuclear Information System (INIS)

McAuley, W.A.

1984-01-01

The 18.14-metric-ton-capacity (20-ton) Load-Cell-Based Weighing System (LCBWS) prototype tested at the Oak Ridge (Tennessee) Gaseous Diffusion Plant March 20-30, 1984, is semiportable and has the potential for being highly accurate. Designed by Brookhaven National Laboratory, it can be moved to cylinders for weighing as opposed to the widely used operating philosophy of most enrichment facilities of moving cylinders to stationary accountability scales. Composed mainly of commercially available, off-the-shelf hardware, the system's principal elements are two load cells that sense the weight (i.e., force) of a uranium hexafluoride (UF 6 ) cylinder suspended from the LCBWS while the cylinder is in the process of being weighed. Portability is achieved by its attachment to a double-hook, overhead-bridge crane. The LCBWS prototype is designed to weigh 9.07- and 12.70-metric ton (10- and 14-ton) UF 6 cylinders. A detailed description of the LCBWS is given, design information and criteria are supplied, a testing procedure is outlined, and initial test results are reported. A major objective of the testing is to determine the reliability and accuracy of the system. Other testing objectives include the identification of (1) potential areas for system improvements and (2) procedural modifications that will reflect an improved and more efficient system. The testing procedure described includes, but is not limited to, methods that account for temperature sensitivity of the instrumentation, the local variation in the acceleration due to gravity, and buoyance effects. Operational and safety considerations are noted. A preliminary evaluation of the March test data indicates that the LCBWS prototype has the potential to have an accuracy in the vicinity of 1 kg

Method of absorbing UF6 from gaseous mixtures in alkamine absorbents

International Nuclear Information System (INIS)

Lafferty, R.H.; Smiley, S.H.; Radimer, K.J.

1976-01-01

A method is described for recovering UF 6 from gaseous mixtures by absorption in a liquid. The liquid absorbent must have a relatively low viscosity and at least one component of the absorbent is an alkamine having less than 3 carbon atoms bonded to the amino nitrogen, less than 2 of the carbon atoms other than those bonded to the amino nitrogen are free of the hydroxy radical and precipitate the absorbed uranium from the absorbent. At least one component of the absorbent is chosen from the group consisting of ethanolamine, diethanolamine, and 3-methyl-3-amino-propane-diol-1,2

Electrochemical separation of uranium in the molten system LiF–NaF–KF–UF{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Korenko, M., E-mail: Michal.Korenko@savba.sk [Fluorine Chemistry Department, Nuclear Research Institute (NRI) Řež Plc., Husinec-Řež 130, CZ-250 68 (Czech Republic); Department of Inorganic Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, SK-845 36 Bratislava (Slovakia); Straka, M.; Szatmáry, L. [Fluorine Chemistry Department, Nuclear Research Institute (NRI) Řež Plc., Husinec-Řež 130, CZ-250 68 (Czech Republic); Ambrová, M. [Institute of Inorganic Chemistry, Technology and Materials, Slovak University of Technology, Radlinského 9, SK-812 37 Bratislava (Slovakia); Uhlíř, J. [Fluorine Chemistry Department, Nuclear Research Institute (NRI) Řež Plc., Husinec-Řež 130, CZ-250 68 (Czech Republic)

2013-09-15

This article is focused on the electrochemical investigation (cyclic voltammetry and related studies) of possible reduction of U{sup 4+} ions to metal uranium in the molten system LiF–NaF–KF(eut.)–UF{sub 4} that can provide basis for the electrochemical extraction of uranium from molten salts. Two-step reduction mechanism for U{sup 4+} ions involving one electron exchange in soluble/soluble U{sup 4+}/U{sup 3+} system and three electrons exchange in the second step were found on the nickel working electrode. Both steps were found to be reversible and diffusion controlled. Based on cyclic voltammetry, the diffusion coefficients of uranium ions at 530 °C were found to be D(U{sup 4+}) = 1.64 × 10{sup −5} cm{sup 2} s{sup −1} and D(U{sup 3+}) 1.76 × 10{sup −5} cm{sup 2} s{sup −1}. Usage of the nickel spiral electrode for electrorefining of uranium showed fairly good feasibility of its extraction. However some oxidant present during the process of electrorefining caused that the solid deposits contained different uranium species such as UF{sub 3}, UO{sub 2} and K{sub 3}UO{sub 2}F{sub 5}.

FTIR spectroscopy of UF6 clustering in a supersonic Laval nozzle

International Nuclear Information System (INIS)

Tanimura, Shinobu; Okada, Yoshiki; Takeuchi, Kazuo

1996-01-01

The clustering of UF 6 seeded in Ar was observed in a continuous supersonic Laval nozzle flow. The onset conditions for UF 6 clustering were investigated by measuring the FTIR spectra of UF 6 monomer and clusters in the nozzle. The onset conditions for the clustering, temperature, density of UF 6 (or partial pressure), and cooling rate, were determined. The onset temperature determined here was higher by 40-50 K than that determined by a light-scattering method. The frequency shift of the main peak of the UF 6 clusters from the monomer peak was about -17 cm -1 , which was smaller than the shift of the crystalline UF 6 by about 11 cm -1 . The increase in temperature caused by the heat of condensation and the change of the spectra of UF 6 clusters with the growth after the onset were also observed. It was shown that the clustering rate due to the collision between the monomer and cluster is much higher than that due to the collision between the monomers. 19 refs., 9 figs

On Line Enrichment Monitor (OLEM) UF₆ Tests for 1.5" Sch40 SS Pipe, Revision 1

Energy Technology Data Exchange (ETDEWEB)

March-Leuba, José A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Garner, Jim [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Younkin, Jim [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Simmons, Darrell W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2016-01-01

As global uranium enrichment capacity under international safeguards expands, the International Atomic Energy Agency (IAEA) is challenged to develop effective safeguards approaches at gaseous centrifuge enrichment plants while working within budgetary constraints. The “Model Safeguards Approach for Gas Centrifuge Enrichment Plants” (GCEPs) developed by the IAEA Division of Concepts and Planning in June 2006, defines the three primary Safeguards objectives to be the timely detection of: 1) diversion of significant quantities of natural (NU), depleted (DU) or low-enriched uranium (LEU) from declared plant flow, 2) facility misuse to produce undeclared LEU product from undeclared feed, and 3) facility misuse to produce enrichments higher than the declared maximum, in particular, highly enriched uranium (HEU). The ability to continuously and independently (i.e. with a minimum of information from the facility operator) monitor not only the uranium mass balance but also the ²³⁵U mass balance in the facility could help support all three verification objectives described above. Two key capabilities required to achieve an independent and accurate material balance are 1) continuous, unattended monitoring of in-process UF₆ and 2) monitoring of cylinders entering and leaving the facility. The continuous monitoring of in-process UF₆ would rely on a combination of load-cell monitoring of the cylinders at the feed and withdrawal stations, online monitoring of gas enrichment, and a high-accuracy net weight measurement of the cylinder contents. The Online Enrichment Monitor (OLEM) is the instrument that would continuously measure the time-dependent relative uranium enrichment, E(t), in weight percent ²³⁵U, of the gas filling or being withdrawn from the cylinders. The OLEM design concept combines gamma-ray spectrometry using a collimated NaI(Tl) detector with gas pressure and temperature data to calculate the enrichment of the UF₆

The regulation of uranium refineries and conversion facilities in Canada

International Nuclear Information System (INIS)

Didyk, J.P.

1986-04-01

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 (UF 6 ). 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

Computer programs for developing source terms for a UF{sub 6} dispersion model to simulate postulated UF{sub 6} releases from buildings

Energy Technology Data Exchange (ETDEWEB)

Williams, W.R.

1985-03-01

Calculational methods and computer programs for the analysis of source terms for postulated releases of UF{sub 6} are presented. Required thermophysical properties of UF{sub 6}, HF, and H{sub 2}O are described in detail. UF{sub 6} reacts with moisture in the ambient environment to form HF and H{sub 2}O. The coexistence of HF and H{sub 2}O significantly alters their pure component properties, and HF vapor polymerizes. Transient compartment models for simulating UF{sub 6} releases inside gaseous diffusion plant feed and withdrawl buildings and cascade buildings are also described. The basic compartment model mass and energy balances are supported by simple heat transfer, ventilation system, and deposition models. A model that can simulate either a closed compartment or a steady-state ventilation system is also discussed. The transient compartment models provide input to an atmospheric dispersion model as output.

Safety provisions for UF{sub 6} handling in the design of a new UF{sub 6} conversion plant

Energy Technology Data Exchange (ETDEWEB)

Bannister, S.P. [British Nuclear Fuels plc, Preston (United Kingdom)

1991-12-31

British Nuclear Fuels plc (BNFL) Fuel Division is currently undertaking the final design and construction of a new UF{sub 6} conversion plant at its production site at Springfields near Preston in the north of England. The Company has gained much experience in the handling of UF{sub 6} during operation of plants on site since 1961. The major hazard occurs during the liquefication cycle and the basis of the maximum credible incident scenario adopted for safety assessment and design purposes is discussed. This paper considers the design features which have been incorporated in the new plant to counter the hazards presented by the presence of UF{sub 6} in gaseous and liquid form and explains current thinking on operational procedures in areas of potential risk such as cylinder filling. The plant emergency response philosophy and systems are described and specific design provisions which have been included to satisfy the UK regulatory bodies are outlined in some detail.

Thermodynamic data for uranium fluorides

International Nuclear Information System (INIS)

Leitnaker, J.M.

1983-03-01

Self-consistent thermodynamic data have been tabulated for uranium fluorides between UF 4 and UF 6 , including UF 4 (solid and gas), U 4 F 17 (solid), U 2 F 9 (solid), UF 5 (solid and gas), U 2 F 10 (gas), and UF 6 (solid, liquid, and gas). Included are thermal function - the heat capacity, enthalpy, and free energy function, heats of formation, and vaporization behavior

Uranium hexafluoride reconversion used for dispersion fuel elements fabrication for IEAR-1/SP reactor; Reconversao de hexafluoreto de uranio para a fabricacao de combustiveis na forma de dispersoes para o reator IEA-R1/SP

Energy Technology Data Exchange (ETDEWEB)

Carvalho, E.F. Urano de; Lainetti, P.E.; Gomes, R.P. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

1996-07-01

In this paper are described the main chemical process employed in the Chemical Processes Division of the Fuel Technology Department - IPEN for conversion of enriched UF{sub 6} in ammonium diuranate - DUA and uranium tetrafluoride - UF{sub 4}. These activities have assured the continuity of fuel elements production at IPEN since 1984. The uranium recovery from scraps of the fuel elements production and the purification processes are also described. Those compounds are important intermediate products in the fabrication routine and in development dispersed fuel elements with higher uranium loading for IEA{sub R}1 research reactor power increase program. (author)

Production of uranium hexafluoride by fluorination tetra-fluoride with elemental fluorine under pressure; Proizvodnja uraovega heksafluorida s tlacnim fluoriranjem uranovega tetrafluorida z elementarnim fluorom

Energy Technology Data Exchange (ETDEWEB)

Lutar, K; Smalc, A; Zemljic, A [Institut Jozef Stefan, Ljubljana (Yugoslavia)

1984-07-01

In the introduction a brief description of some activities of fluorine chemistry department at the J. Stefan Institute is given - from production of elemental fluorine to the investigations in the field of uranium technology. Furthermore, a new method for the production of uranium hexafluoride is described more in detail. The method is based on the fluorination of uranium tetrafluoride with elemental fluorine. (author)

Method to separate off hydrogen fluoride from a uranium hexafluoride-hydrogen fluoride mixture

International Nuclear Information System (INIS)

Pfistermeister, M.; Jokar, J.

1979-01-01

There have been sofar difficulties involved in separating off HF when purifying UF 6 . According to the invention, this can be achieved without great expenditure if one adds a perfluorated amine or derivative of it to the UF 6 -HF mixture. The UF 6 can be separated by simple distillation or sublimation from the hardly-volatile formed tri-(perfluoro-butyl) ammonium fluoride. The adduct formed can be easily split again with NaOH so that the amine can be recycled without loss. (UWI) [de

Use of HGSYSTEM/UF6 and MACCS2 for the Building 9204-2E safety analysis report consequence analysis: General overview and comparison of models

International Nuclear Information System (INIS)

Lombardi, D.A.; Brock, W.R.

1998-01-01

Building 9204-2E is used for assembly, disassembly, and storage of weapons components, and quality operations. The building, built in 1971, is a three story structure approximately 101 m long, 51 m wide, and 21 m high located in the western exclusion area of the Y-12 Plant, Oak Ridge, Tennessee. For these activities, several types of hazardous and radioactive materials are used and stored in Building 9204-2E. During a fire, criticality event, or other accident, the potential exists for the release of uranium and other hazardous materials from the building to the atmosphere. A Safety Analysis Report (SAR) is being prepared for Building 9204-2E, in which the consequences of such releases to on-site workers and the off-site public are being analyzed. Consequence estimates from accidental airborne releases are generally calculated using computer models that simulate dispersion and transport of the plume as it travels downwind. For the Building 9204-2E SAR, two candidate atmospheric dispersion candidate models have bene identified for use: (1) the Heavy Gas System-Uranium Hexafluoride (HGSYSTEM/UF 6 ) Model Suite, and (2) the MELCOR Accident Consequence Code System-2 (MACCS2). The purpose of this paper is to provide a general description of the two model suites and compared model results for generic release cases, representative of those that will be analyzed in the Building 9204-2E SAR. Recommendations for use of the model suites in the SAR are also discussed

Computer-optimized γ-NDA geometries for uranium enrichment verification of gaseous UF6

International Nuclear Information System (INIS)

Wichers, V.A.; Aaldijk, J.K.; Betue, P.A.C. de; Harry, R.J.S.

1993-05-01

An improved collimator pair of novel design tailored for deposit independent enrichment verification of gaseous UF 6 at low pressures in cascade-to-header pipes of small diameters in centrifuge enrichment plants is presented. The designs are adapted for use in a dual-geometry arrangement for simultaneous measurements with both detection geometries. The average measurement time with the dual-geometry arrangement is approximately half an hour for deposit-to-gas activity ratios as high as 20. (orig.)

COGEMA's UMF [Uranium Management Facility

International Nuclear Information System (INIS)

Lamorlette, G.; Bertrand, J.P.

1988-01-01

The French government-owned corporation, COGEMA, is responsible for the nuclear fuel cycle. This paper describes the activities at COGEMA's Pierrelatte facility, especially its Uranium Management Facility. UF6 handling and storage is described for natural, enriched, depleted, and reprocessed uranium. UF6 quality control specifications, sampling, and analysis (halocarbon and volatile fluorides, isotopic analysis, uranium assay, and impurities) are described. In addition, the paper discusses the filling and cleaning of containers and security at UMF

TENERIFE program: high temperature experiments on A 4 tons UF6 container

International Nuclear Information System (INIS)

Casselman, C.; Duret, B.; Seiler, J.M.; Ringot, C.; Warniez, P.; Wataru, M.; Shiomi, S.; Ozaki, S.; Yamakawa, H.

1993-01-01

To know the input of the future thermo-mechanical code, we have to get a better understanding of the thermo-physical evolution of the UF 6 which pressurizes the container. This evolution is function of: a) the heat transfer rate from the fire to the container b) the UF 6 behaviour in the container. These tests are essentially analytical at simulated fire temperatures of between 800 and 1000degC. They use a representative mass of UF 6 (around 4 tons). The tests will not seek to rupture the test container which has a diameter equal to the 48Y container, but shorter length. These tests carried out in realistic conditions (typical thermal gradient at the wall, characteristic period for UF 6 internal mass transfer) should make possible to improve knowledge of two fundamental phenomena: 1) vaporization of UF 6 on contact with the heated wall (around 400degC), a phenomenon which controls the container internal pressurization kinetic, 2) the equivalent conductivity of solid UF 6 , a phenomenon which is linked to the heat transfer by UF 6 vaporization-condensation through the solid's porosities and which depends on the diameter of the container. In addition, they will allow the influence of other parameters to be studied, such as UF 6 container filling mode or the mechanical characteristics of the container material. A UF 6 container fitted with instruments (wall temperature, UF 6 temperature, pressure) is heated by a rapid heat transient in a radiating furnace where the temperature and thermal power supplied can be measured. The test continues until pre-established thresholds have been reached: 1) strain threshold measured on the container surface (strain gauges positioned on the outside), 2) maximum temperature threshold of UF 6 , 3) container internal pressure threshold. (J.P.N.)

2D modelling of a UF6 container in a fire

International Nuclear Information System (INIS)

Duret, B.; Seiler, J.M.

1993-01-01

We present some results on 2D thermal modelisation of the behaviour of UF6 in a fire. A cylindrical container is engulfed by a high temperature space where the heat transfer is expected to occur by radiation only. During the first minutes, we assume that the thermal resistance is between the external wall and the UF6 solid, the heat transfer can be split up into three kinds: 1) conduction to solid UF6 through a contact surface. 2) radiative transfer. 3) gas layer with a small heat conductance. This thermal resistance is initially determined by the UF6 filling type, shape and also is time dependant by thermal dilatation effects. On the onset of liquifying the heat transfer increases because of the larger liquid exchange. The liquid and boiling heat flow is then calculated by a model on the basis of classical correlations in vertical cavities. Numerical evaluations have been performed with a finite element model using: ANSYS. With a realistic hypothesis, the effect of the following parameters is estimated: thermal conductivity of UF6 solid, contact surface fraction, UF6 emissivity, gas gap thickness, liquid UF6 wall exchange, solid liquid transition criteria, non condensation factor k. (J.P.N.)

Математическое моделирование процесса десублимации гексафторида урана

OpenAIRE

Малюгин, Р. В.; Цимбалюк, Александр Федорович

2015-01-01

A non-stationary mathematical model of desublimation UF6 in vertical tanks considers the movement of gaseous uranium hexafluoride contains in the article. Results of calculation of time dependence of the linear velocity desublimation, the thickness of the resulting layer of the solid phase, the temperature distribution in the tank wall - desublimation layer, filling dynamics of vertical tank B-12 by solid UF6 are presented. Calculations have shown that the 70% of B-12 tank is filled by desubl...

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 ...

UF6 Cylinder Imaging by Fast Neutron Transmission Tomography

International Nuclear Information System (INIS)

McElroy, R.; Hausladen, P.; Blackston, M.; Croft, S.

2015-01-01

The common use Non-Destructive Assay techniques for the determination of 235 U enrichment and mass of UF6 cylinders used in the production of nuclear reactor fuel require prior knowledge of the physical distribution of the UF6 within the cylinder. The measurement performance for these techniques is typically evaluated based on assumed bounding case distributions of the material. However, little direct data such as radiographic or tomographic images, regarding the distribution of the UF6 within the cylinder is available against which to judge these assumptions. We have developed and tested a prototype active neutron tomographic imaging system employing an Associated Particle Imaging (API) neutron generator and an array of pixelated neutron scintillation counters. This system has been successfully used to obtain the 3-dimensional map of the distribution of UF6 within a type 12B storage cylinder. Results from these measurements are presented and the potential performance and utility of this technique with larger 30B and 48Y cylinders is discussed. (author)

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.

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)

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 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

Thermodynamic data for uranium fluorides

Energy Technology Data Exchange (ETDEWEB)

Leitnaker, J.M.

1983-03-01

Self-consistent thermodynamic data have been tabulated for uranium fluorides between UF/sub 4/ and UF/sub 6/, including UF/sub 4/ (solid and gas), U/sub 4/F/sub 17/ (solid), U/sub 2/F/sub 9/ (solid), UF/sub 5/ (solid and gas), U/sub 2/F/sub 10/ (gas), and UF/sub 6/ (solid, liquid, and gas). Included are thermal function - the heat capacity, enthalpy, and free energy function, heats of formation, and vaporization behavior.

Anisotropy of the fluorine chemical shift tensor in UF6

International Nuclear Information System (INIS)

Rigny, P.

1965-04-01

An 19 F magnetic resonance study of polycrystalline UF 6 is presented. The low temperature complex line can be analyzed as the superposition of two distinct lines, which is attributed to a distortion of the UF 6 octahedron in the solid. The shape of the two components is studied. Their width is much larger than the theoretical dipolar width, and must be explained by large anisotropies of the fluorine chemical shift tensors. The resulting shape functions of the powder spectra are determined. The values of the parameters of the chemical shift tensors yield estimates of the characters of the U-F bonds, and this gives some information on the ground state electronic wave function of the UF 6 molecule in the solid. (author) [fr

Isotopic analysis of uranium hexafluoride highly enriched in U-235

International Nuclear Information System (INIS)

Chaussy, L.; Boyer, R.

1968-01-01

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) [fr

Criticality analysis in uranium enrichment plant

International Nuclear Information System (INIS)

Okamoto, Tsuyoshi; Kiyose, Ryohei

1977-01-01

In a large scale uranium enrichment plant, uranium inventory in cascade rooms is not very large in quantity, but the facilities dealing with the largest quantity of uranium in that process are the UF 6 gas supply system and the blending system for controlling the product concentration. When UF 6 spills out of these systems, the enriched uranium is accumulated, and the danger of criticality accident is feared. If a NaF trap is placed at the forestage of waste gas treatment system, plenty of UF 6 and HF are adsorbed together in the NaF trap. Thus, here is the necessity of checking the safety against criticality. Various assumptions were made to perform the computation surveying the criticality of the system composed of UF 6 and HF adsorbed on NaF traps with WIMS code (transport analysis). The minimum critical radius resulted in about 53 cm in case of 3.5% enriched fuel for light water reactors. The optimum volume ratio of fissile material in the double salt UF 6 .2NaF and NaF.HF is about 40 vol. %. While, criticality survey computation was also made for the annular NaF trap having the central cooling tube, and it was found that the effect of cooling tube radius did not decrease the multiplication factor up to the cooling tube radius of about 5 cm. (Wakatsuki, Y.)

Evaluation of a redesigned 3/4-inch uranium hexafluoride cylinder valve stem

International Nuclear Information System (INIS)

Zonner, L.A.; Wamsley, S.D.

1978-01-01

The performance of a redesigned 3/4-in. uranium hexafluoride cylinder valve stem has been evaluated at the Portsmouth Gaseous Diffusion Plant. Prototypes, machined from Monel bar stock and having a 45 0 tip angle instead of the 15 0 tip angle of the standard valve stem, were fabricated. Tests included: cyclic leak evaluation; flow restriction determination; wear testing with uranyl fluoride deposits in the valve seat; stress corrosion testing; field testing (in previously rejected valve bodies); and production leak testing. Because their overall test performance was excellent, actual production usage of the redesigned stems was initiated. The in-service performance of valves fitted with redesigned stems has been significantly superior to that of valves having the standard stems: rejection rates have been 0.7 and 16.6 percent, respectively. Recommendations are made to replace all 15 0 angle tip stems presently in service with new stems having a 45 0 angle tip and to specify the new stem tip design for future 3/4-in. valve purchases

Fluorine nuclear magnetic resonance study of enrichment effects in gaseous, liquid and solid uranium hexafluoride

International Nuclear Information System (INIS)

Ursu, I.; Demco, D.E.; Simplaceanu, V.; Valcu, N.

1977-01-01

The nuclear magnetic resonance method is able to provide information concerning the isotopic content of 235 U in UF 6 by means of measuring the nuclear magnetic transverse relaxation time (T,L2) of 19 F nuclei in liquid UF 6 . In this work, the sources of errors in the T 2 measurements have been analysed and methods for reducing them are dicussed. Typical errors in T 2 determinations are below 2%. The enrichment estimations made by using the linear calibration curves had a deviation of less than 2% with some exceptions. It was found that the chemical impurities may significantly affect the enrichment estimations. 19 F NMR spectra of liquid and gaseous UF 6 at low pressures did not reveal any structure or enrichment effect. The longitudinal nuclear magnetic relaxation of 19 F nuclei in low pressure, gaseous and solid UF 6 showed no enrichment dependence, nor the dipolar relaxation time in solid UF 6 did. (author)

Development and design of a UF6 gas pressure meter for 42 mm pipes

International Nuclear Information System (INIS)

Peters, E.; Wichers, V.A.

1995-08-01

X-ray fluorescence (XRF) has proved to be a feasible method of measuring the pressure of UF 6 -gas for enrichment verification purposes. Complications will arise under extreme conditions, such as high uranium deposit to gas ratios, pipe diameters smaller than 40 mm and pressures less than 100 Pa. This report presents an experimental analysis of the XRF method for design worst case conditions for 42 outer diameter cascade-to-header pipes and the development of a prototype measurement device. This prototype is integrated in the construction of the enrichment verification system. (orig.)

Characterization of process holdup material at the Portsmouth Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Boyd, D.E.; Miller, R.R.

1986-01-01

The cascade material balance area at the Portsmouth Gaseous Diffusion Plant is characterized by continuous, large, in-process inventories of gaseous uranium hexafluoride (UF 6 ) and very large inputs and outputs of UF 6 over a complete range of 235 U enrichments. Monthly inventories are conducted to quantify the in-place material, but the inventory techniques are blind to material not in the gas phase. Material is removed from the gas phase by any one of four mechanisms: (1) freeze-outs which are the solidification of UF 6 , (2) inleakage of wet air which produces solid uranium oxyfluorides, (3) consumption of uranium through UF 6 reaction with internal metal surfaces, and (4) adsorption of UF 6 on internal surfaces. This presentation describes efforts to better characterize and, where possible, to eliminate or reduce the effects of these mechanisms on material accountability. Freeze-outs and wet air deposits occur under absormal operating conditions, and techniques are available to prevent, detect and reverse them. Consumption and adsorption occur under normal operating conditions and are more complex to manage, however, computer models have been developed to quantify monthly the net effects due to consumption and adsorption. These models have shown that consumption and adsorption effects on inventory differences are significant

Perekayasaan Heat Exchanger Sebagai Pemanas Umpan Uf 6 Dalam Pabrik Elemen Bakar Nuklir

OpenAIRE

Zacharias, Petrus; Pancoko, Marliyadi

2011-01-01

DESIGN OF HEAT EXCHANGER FOR HEATING UF6 FEED IN NUCLEAR FUEL ELEMENT PLANT. The process of conversion of UF6 to UO through Integrated Dry Route (IDR) i s done in a rotary kiln reactor. There are two stages of initi al treatment / conditioni ng before inserting the UF 6 in to the reactor : changing UF6 2 solid into the gas phase at a temperature of 60°C in an evaporator, and then, raising the temperature of UF C to 2900 C i n a Heat Exchanger (HE). Therefore it i s necessary to desi gn...

Testing a technical-scale counterflow compact heat exchanger for the separation of uranium hexafluoride from hydrogen

International Nuclear Information System (INIS)

Hornberger, P.; Seidel, D.; Steinhaus, H.

1981-07-01

When enriching the light uranium isotope U-235 according to the separation nozzle method, UF 6 and light auxiliary gas (H 2 ) must be separated from each other at the head as well as at the shoulder of the cascade. After pre-separation at a special separation nozzle stage, fine separation is planned by means of a low-temperature separator made as a compact heat exchanger. This report describes first testing under process conditions of a representative section of the separator blocks intended for technical-scale operation. It is proved that the rated loading capacity is attained while the residual UF 6 concentration contained in the escaping hydrogen can be lowered down to values less than 1 ppm. It is further shown that the requirement of constant pressure drop at the separator, which is decisive for the smooth interplay of preseparator stage and low-temperature separator, can be imposed by direct control of the supply of the refrigerating medium through the variable to be kept constant. A concept of control is proposed for industrial application necessitating the operation of several low-temperature separators staggered in terms of time. This concept allows the relatively simple optimum utilization of the separator capacity even under variable operating conditions. (orig.) [de

UF{sub 6} cylinder inspections at PGDP

Energy Technology Data Exchange (ETDEWEB)

Lamb, G.W.; Whinnery, W.N. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

1991-12-31

Routine inspections of all UF{sub 6} cylinders at the Paducah Gaseous Diffusion Plant have been mandated by the Department of Energy. A specific UF{sub 6} cylinder inspection procedure for what items to inspect and training for the operators prior to inspection duty are described. The layout of the cylinder yards and the forms used in the inspections are shown. The large number of cylinders (>30,000) to inspect and the schedule for completion on the mandated time table are discussed. Results of the inspections and the actions to correct the deficiencies are explained. Future inspections and movement of cylinders for relocation of certain cylinder yards are defined.

Assessment of Reusing 14-Ton, Thin-Wall, Depleted UF6 Cylinders as LLW Disposal Containers

International Nuclear Information System (INIS)

O'Connor, D.G.; Poole, A.B.; Shelton, J.H.

2000-01-01

Approximately 700,000 MT of DUF 6 is stored, or will be produced under a current agreement with the USEC, at the Paducah site in Kentucky, Portsmouth site in Ohio, and ETTP site in Tennessee. On July 21, 1998, the 105th Congress approved Public Law 105-204, which directed that facilities be built at the Kentucky and Ohio sites to convert DUF 6 to a stable form for disposition. On July 6, 1999, the Department of Energy (DOE) issued the ''Final Plan for the Conversion of Depleted Uranium Hexafluoride as Required by Public Law 105-204'', in which DOE committed to develop a ''Depleted Uranium Hexafluoride Materials Use Roadmap''. On September 1,2000, DOE issued the ''Draft Depleted Uranium Hexafluoride Materials Use Roadmap'' (Roadmap), which provides alternate paths for the long-term storage, beneficial use, and eventual disposition of each product form and material that will result from the DUF 6 conversion activity. One of the paths being considered for DUF 6 cylinders is to reuse the empty cylinders as containers to transport and dispose of LLW, including the converted DU. The Roadmap provides results of the many alternate uses and disposal paths for conversion products and the empty DUF 6 storage cylinders. As a part of the Roadmap, evaluations were conducted of cost savings, technical maturity, barriers to implementation, and other impacts. Results of these evaluations indicate that using the DUF 6 j storage cylinders as LLW disposal containers could provide moderate cost savings due to the avoided cost of purchasing LLW packages and the avoided cost of disposing of the cylinders. No significant technical or institutional .issues were identified that.would make using cylinders as LLW packages less effective than other disposition paths. Over 58,000 cylinders have been used, or will be used, to store DUF 6 . Over 5 1,000 of those cylinders are 14TTW cylinders with a nominal wall thickness of 5/16-m (0.79 cm). These- 14TTW cylinders, which have a nominal diameter

Morse-Morse-Spline-Van der Waals intermolecular potential suitable for hexafluoride gases

International Nuclear Information System (INIS)

Coroiu, Ilioara

2004-01-01

Several effective isotopic pair potential functions have been proposed to characterize the bulk properties of quasispherical molecules, in particular the hexafluorides, but none got a success. Unfortunately, these potentials have repulsive walls steeper than those which describe the hexafluorides. That these intermolecular potentials are not quite adequate is shown by the lack of complete agreement between theory and experiment even for the rare gases. Not long ago, R. A. Aziz et al. have constructed a Morse-Morse-Spline-Van der Waals (MMSV) potential. The MMSV potential incorporates the determination of C 6 dispersion coefficient and it reasonably correlates second virial coefficients and viscosity data of sulphur hexafluoride at the same time. None of the potential functions previously proposed in literature could predict these properties simultaneously. We calculated the second virial coefficients and a large number of Chapman-Cowling collision integrals for this improved intermolecular potential, the MMSV potential. The results were tabulated for a large reduced temperature range, kT/ε from 0.1 to 100. The treatment was entirely classical and no corrections for quantum effects were made. The higher approximations to the transport coefficients and the isotopic thermal diffusion factor were also calculated and tabulated for the same range. In this paper we present the evaluation of the uranium hexafluoride potential parameters for the MMSV intermolecular potential. To find a single set of potential parameters which could predict all the transport properties (viscosity, thermal conductivity, self diffusion, etc.), as well as the second virial coefficients, simultaneously, the method suggested by Morizot and a large assortment of literature data were used. Our results emphasized that the Morse-Morse-Spline-Van der Waals potential have the best overall predictive ability for gaseous hexafluoride data, certain for uranium hexafluoride. (author)

Use of Savannah River Site facilities for blend down of highly enriched uranium

International Nuclear Information System (INIS)

Bickford, W.E.; McKibben, J.M.

1994-02-01

Westinghouse Savannah River Company was asked to assess the use of existing Savannah River Site (SRS) facilities for the conversion of highly enriched uranium (HEU) to low enriched uranium (LEU). The purpose was to eliminate the weapons potential for such material. Blending HEU with existing supplies of depleted uranium (DU) would produce material with less than 5% U-235 content for use in commercial nuclear reactors. The request indicated that as much as 500 to 1,000 MT of HEU would be available for conversion over a 20-year period. Existing facilities at the SRS are capable of producing LEU in the form of uranium trioxide (UO 3 ) powder, uranyl nitrate [UO 2 (NO 3 ) 2 ] solution, or metal. Additional processing, and additional facilities, would be required to convert the LEU to uranium dioxide (UO 2 ) or uranium hexafluoride (UF 3 ), the normal inputs for commercial fuel fabrication. This study's scope does not include the cost for new conversion facilities. However, the low estimated cost per kilogram of blending HEU to LEU in SRS facilities indicates that even with fees for any additional conversion to UO 2 or UF 6 , blend-down would still provide a product significantly below the spot market price for LEU from traditional enrichment services. The body of the report develops a number of possible facility/process combinations for SRS. The primary conclusion of this study is that SRS has facilities available that are capable of satisfying the goals of a national program to blend HEU to below 5% U-235. This preliminary assessment concludes that several facility/process options appear cost-effective. Finally, SRS is a secure DOE site with all requisite security and safeguard programs, personnel skills, nuclear criticality safety controls, accountability programs, and supporting infrastructure to handle large quantities of special nuclear materials (SNM)

Optimization of public protection in the case of transportation of radioactive materials

International Nuclear Information System (INIS)

Pages, P.; Hubert, P.

1986-09-01

The initial purpose of the study was to assess risk to the public associated with UF 6 transportation in France as projected for the years to come. In a first stage a particular risk assessment methodology has been developed at the CEPN in the field of radioactive material transportation, through this first example and some others. Then a number of questions were raised as to the opportunity of given safety measures, associated for example with possible changes in the regulations. One such measure could be to adopt an overpack for natural uranium hexafluoride containers. This particular action and others bearing on either natural or enriched uranium hexafluoride transportation in both truck and rail modes were envisaged. The case study presented here deals with the comparison of a set of such alternative options aiming at reducing the risk to the public in the transportation of natural UF 6 by truck in France. Risk from the transportation only itself is taken into account, risk is assessed for accident situations only, health detriment is evaluated only for the consequences of the release itself

The electron spectrum of UF6 recorded in the gas phase

Science.gov (United States)

Mârtensson, N.; Malmquist, P.-Å.; Svensson, S.; Johansson, B.

1984-06-01

Gas phase core and valence electron spectra from UF6, excited by AlKα monochromatized x rays, in the binding energy range 0-1000 eV are presented. It is shown that the AlKα excited valence electron spectrum can be used to reassign the highest occupied molecular orbital (HOMO) in UF6. Many-body effects on the core levels are discussed and core level lifetimes are determined. The shift between solid phase and gas phase electron binding energies for core lines is used to discuss the U5 f population in UF6.

Development and design of a UF{sub 6} gas pressure meter for 42 mm pipes

Energy Technology Data Exchange (ETDEWEB)

Peters, E.; Wichers, V.A.

1995-08-01

X-ray fluorescence (XRF) has proved to be a feasible method of measuring the pressure of UF{sub 6}-gas for enrichment verification purposes. Complications will arise under extreme conditions, such as high uranium deposit to gas ratios, pipe diameters smaller than 40 mm and pressures less than 100 Pa. This report presents an experimental analysis of the XRF method for design worst case conditions for 42 outer diameter cascade-to-header pipes and the development of a prototype measurement device. This prototype is integrated in the construction of the enrichment verification system. (orig.).

Gas-phase UF6 enrichment monitor for enrichment plant safeguards

International Nuclear Information System (INIS)

Strittmatter, R.B.; Tape, J.W.

1980-03-01

An in-line enrichment monitor is being developed to provide real-time enrichment data for the gas-phase UF 6 feed stream of an enrichment plant. The nondestructive gamma-ray assay method can be used to determine the enrichment of natural UF 6 with a relative precision of better than 1% for a wide range of pressures

Emergency preparedness and response in case of a fire accident with (UF6) packages tracking Suez Canal