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Validation of KENO V. a. and two cross-section libraries for criticality calculations of low-enriched uranium systems

Description: The SCALE code system, utilizing the Monte Carlo computer code KENO V.a, was employed to calculate 37 critical experiments. The critical assemblies had /sup 235/U enrichments of 5% or less and cover a variety of geometries and materials. Values of k/sub eff/ were calculated using two different results using either of the cross-section libraries. The 16-energy-group Hansen-Roach and the 27-energy-group ENDF/B-IV cross-section libraries, available in SCALE, were used in this validation study, and both give good results for the experiments considered. It is concluded that the code and cross sections are adequate for low-enriched uranium systems and that reliable criticality safety calculations can be made for such systems provided the limits of validated applicability are not exceeded.
Date: July 1, 1985
Creator: Easter, M.E.
Partner: UNT Libraries Government Documents Department

Validation of the Monte Carlo Criticality Program KENO V. a for highly-enriched uranium systems

Description: A series of calculations based on critical experiments have been performed using the KENO V.a Monte Carlo Criticality Program for the purpose of validating KENO V.a for use in evaluating Y-12 Plant criticality problems. The experiments were reflected and unreflected systems of single units and arrays containing highly enriched uranium metal or uranium compounds. Various geometrical shapes were used in the experiments. The SCALE control module CSAS25 with the 27-group ENDF/B-4 cross-section library was used to perform the calculations. Some of the experiments were also calculated using the 16-group Hansen-Roach Library. Results are presented in a series of tables and discussed. Results show that the criteria established for the safe application of the KENO IV program may also be used for KENO V.a results.
Date: November 1, 1984
Creator: Knight, J.R.
Partner: UNT Libraries Government Documents Department

Towards a quantitative approach to the utilization of magnetic effects as a means of isotopic enrichment

Description: The photolysis of methyldesoxybenzoin in sodium dodecyl sulfate micellar solutions, produces benzaldehyde and styrene as disproportionation products of the triplet geminate radical pair. We have found that both the benzaldehyde and the recovered methyldeoxybenzoin are enriched in 13-C. These results provide the first direct evidence that both recombination and disproportionation are identically selective to the magnetic isotope effect, an important point anticipated by theory, but previously untested. An investigation of the photostereoisomerization of the diasteromers of 2,4-diphenylpentane-3-one in micellar solutions has allowed a quantitative analysis of the probabilities of recombination of the micellized primary geminate radical pair toward formation of different combination products. The results show that within the confidence provided by highly accurate data, the primary geminate radical pairs recombine to regenerate the precursor substrate structure or diastereomer with equal probability.
Date: May 1, 1992
Creator: Turro, N.J.
Partner: UNT Libraries Government Documents Department

Towards a quantitative approach to the utilization of magnetic effects as a means of isotopic enrichment. [Progress report, January 1, 1989--April 1, 1992]

Description: The photolysis of methyldesoxybenzoin in sodium dodecyl sulfate micellar solutions, produces benzaldehyde and styrene as disproportionation products of the triplet geminate radical pair. We have found that both the benzaldehyde and the recovered methyldeoxybenzoin are enriched in 13-C. These results provide the first direct evidence that both recombination and disproportionation are identically selective to the magnetic isotope effect, an important point anticipated by theory, but previously untested. An investigation of the photostereoisomerization of the diasteromers of 2,4-diphenylpentane-3-one in micellar solutions has allowed a quantitative analysis of the probabilities of recombination of the micellized primary geminate radical pair toward formation of different combination products. The results show that within the confidence provided by highly accurate data, the primary geminate radical pairs recombine to regenerate the precursor substrate structure or diastereomer with equal probability.
Date: May 1, 1992
Creator: Turro, N. J.
Partner: UNT Libraries Government Documents Department

Transition phase of the whole-core demonstration at the Oak Ridge Research Reactor

Description: The transition from operation of the Oak Ridge Research Reactor with high-enrichment uranium (HEU) fuel to operation with low-enrichment uranium (LEU) fuel is nearing completion. The systematics of the replacement of the HEU fuel with the LEU fuel are discussed. The results of the core physics measurements that have been conducted during the transition phase are described.
Date: January 1, 1986
Creator: Hobbs, R.W.; Bretscher, M.M.; Cornella, R.J. & Snelgrove, J.L.
Partner: UNT Libraries Government Documents Department

Characterization of uranium surfaces machined with aqueous propylene glycol-borax or perchloroethylene-mineral oil coolants

Description: The use of perchloroethylene (perc) as an ingredient in coolants for machining enriched uranium at the Oak Ridge Y-12 Plant has been discontinued because of environmental concerns. A new coolant was substituted in December 1985, which consists of an aqueous solution of propylene glycol with borax (sodium tetraborate) added as a nuclear poison and with a nitrite added as a corrosion inhibitor. Uranium surfaces machined using the two coolants were compared with respects to residual contamination, corrosion or corrosion potential, and with the aqueous propylene glycol-borax coolant was found to be better than that of enriched uranium machined with the perc-mineral oil coolant. The boron residues on the final-finished parts machined with the borax-containing coolant were not sufficient to cause problems in further processing. All evidence indicated that the enriched uranium surfaces machined with the borax-containing coolant will be as satisfactory as those machined with the perc coolant.
Date: December 31, 1986
Creator: Cristy, S.S.; Bennett, R.K. Jr.; Dillon, J.J.; Richards, H.L.; Seals, R.D. & Byrd, V.R.
Partner: UNT Libraries Government Documents Department

Conference on enrichment services marketing

Description: Purpose of the meeting was to discuss the draft terms and conditions of DOE's Adjustable Fixed-Commitment (AFC) contract, which was developed to implement the United States nuclear power policy objective of assured nuclear fuel supply on attractive terms and conditions. Nine presentations were made by representatives of both DOE Headquarters and DOE's Oak Ridge Operations Office which co-sponsored the meeting. A question and answer session was held during the afternoon, and these are also presented in this document. Separate abstracts were prepared for eight of the presentations. (DLC)
Date: January 1, 1978
Partner: UNT Libraries Government Documents Department

Physical inventory verification exercise for a highly enriched uranium fabrication facility

Description: The International Atomic Energy Agency, in collaboration with the US Support Program (POTAS), has developed and conducted a training exercise simulating a physical inventory verification (PIV) at a highly enriched uranium (HEU) fabrication facility. This exercise is part of a series sponsored by the POTAS program, including PIVs at light-water reactors and plutonium fabrication facilities. The first HEU exercise took place in September 1985 at Los Alamos National Laboratory and a second is scheduled for Spring, 1987 at JRC, ISPRA. The main objectives of these exercises are: to provide the opportunity for inspectors to test and evaluate the use of nondestructive assay (NDA) equipment and computer software under conditions similar to those found during actual inspections; to use the data generated to evaluate different inspection procedures and strategies; and to exchange ideas on PIV procedures between the three operations divisions. Because the exercises are conducted in a neutral environment, free of the time pressure often found in actual inspections, it is possible for the inspectors to achieve the course objectives.
Date: January 1, 1986
Creator: Abedin-Zadeh, R. & Augustson, R.H.
Partner: UNT Libraries Government Documents Department

Criticality safety review of 2 1/2 -, 10-, and 14-ton UF sub 6 cylinders

Description: Currently, UF{sub 6} cylinders designed to contain 2{1/2} tons of UF{sub 6} are classified as Fissile Class 2 packages with a transport index (TI) of 5 for the purpose of transportation. The 10-ton UF{sub 6} cylinders are classified as Fissile Class 1 with no TI assigned for transportation. The 14-ton cylinders, although not certified for transport with enrichments greater than 1 wt % because they have no approved overpack, can be used in on-site operations for enrichments greater than 1 wt %. The maximum {sup 235}U enrichments for these cylinders are 5.0 wt % for the 2{1/2}-ton cylinder and 4.5 wt % for the 10- and 14-ton cylinders. This work reviews the suitability for reclassification of the 2{1/2}-ton UF{sub 6} packages as Fissile Class 1 with a maximum {sup 235}U enrichment of 5 wt %. Additionally, the 10- and 14-ton cylinders are reviewed to address a change in maximum {sup 235}U enrichment from 4.5 to 5 wt %. Based on this evaluation, the 2{1/2}-ton UF{sub 6} cylinders meet the 10 CFR.71 criteria for Fissile Class 1 packages, and no TI is needed for criticality safety purposes; however, a TI may be required based on radiation from the packages. Similarly, the 10- and 14-ton UF{sub 6} packages appear acceptable for a maximum enrichment rating change to 5 wt % {sup 235}U. 11 refs., 13 figs., 7 tabs.
Date: October 1, 1991
Creator: Broadhead, B.L.
Partner: UNT Libraries Government Documents Department

Irradiation testing of miniature fuel plates for the RERTR program. [Reduced Enrichment Research and Test Reactors]

Description: An irradiation test facility, which provides a test bed for irradiating a variety of miniature fuel plates (miniplates) for the Reduced Enrichment Research and Test Reactors (RERTR) program, has been placed into operation. These tests screen various candidate fuel materials on their suitability for replacing the highly enriched uranium fuel materials currently used by the world's test and research reactors with a lower enrichment fuel material, without significantly degrading reactor operating characteristics and power levels. The use of low uranium enrichment of about 20% /sup 235/U in place of highly enriched fuel for these reactors would reduce the potential for /sup 235/U diversion. The irradiation test facility, designated as HFED, is operating in core position E-7 in the Oak Ridge Research Reactor (ORR), a 30-MW water-moderated reactor. The miniplates will achieve burnups of up to approx. 2.2 x 10/sup 27/ fissions/m/sup 3/ of fuel.
Date: July 1, 1981
Creator: Senn, R.L. & Martin, M.M.
Partner: UNT Libraries Government Documents Department

Measurement of the enrichment of uranium in the pipework of a gas centrifuge enrichment plant

Description: The US and UK have been separately working on the development of a NDA instrument to determine the enrichment of gaseous UF/sub 6/ at low pressures in cascade header pipework in line with the conclusions of the Hexapartite Safeguards Project viz. the instrument is capable of making a ''go/no go'' decision of whether the enrichment is less than/greater than 20%. Recently, there has been a series of very useful technical exchanges of ideas and information between the two countries. This has led to a technical formulation for such an instrumentation based on ..gamma..-ray spectrometry which, although plant-specific in certain features, nevertheless is based on the same physical principles. Experimental results from commercially operating enrichment plants are very encouraging and indicate that a complete measurement including set up time on the pipe should be attainable in about 30 minutes when measuring pipes of diameter around 110 mm. 5 refs., 4 figs.
Date: January 1, 1985
Creator: Packer, T.W.; Lees, E.W.; Close, D.; Nixon, K.V.; Pratt, J.C. & Strittmatter, R.
Partner: UNT Libraries Government Documents Department

Safety analysis of the main vault at TA-41, LASL

Description: Safety considerations discussed in this report show that special nuclear materials stored at a Los Alamos Scientific Laboratory facility (TA-41) present no inappropriate risk to workers or the public. The report addresses nuclear criticality, fire, and radioactive contamination potentials, as well as physical protection and material safeguards.
Date: February 1, 1978
Creator: Ehrenkranz, T.E.; Dahl, D.A.; Plassmann, E.H.; Pogna, R. & Smith, D.R.
Partner: UNT Libraries Government Documents Department

Materials accounting considerations for international safeguards in a light-water reactor fuels reprocessing plant

Description: This paper summarizes the requirements and functions of materials measurement and accounting systems applicable to large (1500 metric tonnes heavy metal per year - MTHM/y) future reprocessing facilities as well as small (210 MTHM/y) plants that are presently under IAEA safeguards. The effectiveness of conventional and proposed improved measurement and accounting systems were compared using modeling, simulation, and analysis procedures. The study showed that conventional accountability can meet IAEA goal quantities and detection times in these reference facilities only for low-enriched uranium. Dynamic materials accounting may meet IAEA goals for detecting abrupt (1-3 wks) diversion of 8 kg of plutonium. Current or projected techniques cannot meet the one-year protracted diversion goal for plutonium if this goal is based on an absolute 8 kg quantity.
Date: January 1, 1979
Creator: Hakkila, E.A.; Cobb, D.D.; Dayem, H.A.; Dietz, R.J.; Kern, E.A. & Shipley, J.P.
Partner: UNT Libraries Government Documents Department

Science, technology, and the industrialization of laser-driven processes

Description: Members of the laser program at Lawrence Livermore National Laboratory (LLNL) reviewed potential applications of lasers in industry, some of which are: isotope separation; cleanup of radioactive waste; trace impurity removal; selective chemical reactions; photochemical activation or dissociation of gases; control of combustion particulates; crystal and powder chemistry; and laser induced biochemistry. Many of these areas are currently under active study in the community. The investigation at LLNL focused on laser isotope separation of atomic uranium because of the large demand (> 1000 tonnes/year) and high product enrichment price (> $600/kg of product) for material used as fuel in commercial light-water nuclear power reactors. They also believed that once the technology was fully developed and deployed, it could be applied directly to separating many elements economically on an industrial scale. The Atomic Vapor Laser Isotope Separation (AVLIS) program at LLNL has an extensive uranium and plutonium program of >$100 M in FY85 and a minor research program for other elements. This report describes the AVLIS program conducted covering the following topics; candidate elements; separative work units; spectroscopic selectivety; major systems; facilities; integrated process model;multivariable sensitivety studies; world market; and US enrichment enterprise. 23 figs. (AT)
Date: May 1, 1985
Creator: Davis, J.I. & Paisner, J.A.
Partner: UNT Libraries Government Documents Department

Nuclear criticality assessment of LEU and HEU element storage

Description: Criticality aspects of storing LEU (20%) and HEU (93%) fuel elements have been evaluated as a function of /sup 235/U loading, element geometry, and fuel type. Silicide, oxide, and aluminide fuel types have been evaluated ranging in /sup 235/U loading from 180 to 620 g per element and from 16 to 23 plates per element. Storage geometry considerations have been evaluated for fuel element separations ranging from closely packed formations to spacings of several centimeters between elements. Data are presented in a form in which interpolations may be made to estimate the eigenvalue of any fuel element storage configuration that is within the range of the data.
Date: January 1, 1983
Creator: Pond, R.B. & Matos, J.E.
Partner: UNT Libraries Government Documents Department

Scale system cross section validation with shipping-cask critical experiments

Description: Results are presented of 70 critical experiments simulating LWR fuel element shipping casks and storage pools. Four series of experiments were analyzed: 2.35% enriched UO/sub 2/ rods at a lattice pitch of 2.032 cm, 4.29 % enriched rods at 2.54 cm pitch, and these lattices positioned between simulated Pb and depleted U shields. Results show that each of the three libraries (ENDF/B-IV, GAM-THERMOS, Hansen-Roach) is adequate. 2 tables. (DLC)
Date: January 1, 1979
Creator: Westfall, R.M. & Knight, J.R.
Partner: UNT Libraries Government Documents Department

Overview of reduced enrichment fuels: Development, testing, and specification

Description: The US Reduced Enrichment Research and Test Reactor (RERTR) Program was established in 1978 to provide the technical means to operate research and test reactors with low enrichment uranium (LEU) fuels without significant penalty in experiment performance, operation costs, component modifications, or safety characteristics. This paper discusses relevant developments in fuel developments. 9 refs., 1 tab.
Date: January 1, 1987
Creator: Snelgrove, J.L.
Partner: UNT Libraries Government Documents Department

Recent developments of the US RERTR program

Description: The status of the US Reduced Enrichment Research and Test Reactor (RERTR) Program is reviewed. After a brief outline of the RERTR Program objectives, goals and past accomplishments, emphasis is placed on the developments which took place during 1983 and on current program plans and schedules. Most program activities have proceeded as planned and a combination of two silicide fuels (U/sub 3/Si/sub 2/-Al and U/sub 3/Si-Al) was found to hold excellent promise for achieving the long-term program goals. A modification of the program plan, including the development and demonstration of those fuels, was prepared and is now being implemented. The uranium density of qualified RERTR fuels for plate-type reactors is forecasted to grow by approximately 1 g U/cm/sup 3/ each year, from the current 1.7 g U/cm/sup 3/ to the 7.0 g U/cm/sup 3/ which will be reached in 1988. The technical needs of research reactors for HEU exports are also forecasted to undergo a gradual and dramatic decline in the coming years.
Date: January 1, 1983
Creator: Travelli, A.
Partner: UNT Libraries Government Documents Department

Overview of enrichment plant safeguards

Description: The relationship of enrichment plant safeguards to US nonproliferation objectives and to the operation and management of enrichment facilities is reviewed. During the review, the major components of both domestic and international safeguards systems for enrichment plants are discussed. In discussing domestic safeguards systems, examples of the technology currently in use to support nuclear materials accountability are described including the measurement methods, procedures and equipment used for weighing, sampling, chemical and isotopic analyses and nondestructive assay techniques. Also discussed is how the information obtained as part of the nuclear material accountancy task is useful to enrichment plant operations. International material accountancy verification and containment/surveillance concepts for enrichment plants are discussed, and the technologies presently being developed for international safeguards in enrichment plants are identified and the current development status is reported.
Date: January 1, 1982
Creator: Swindle, D.W. Jr. & Wheeler, L.E.
Partner: UNT Libraries Government Documents Department

Critical separation between subcritical clusters of 2. 35 wt 235/U enriched UO/ 2/ rods in water with fixed neutron poisons

Description: A program to provide experimental data for validating calculational techniques and nuclear data used in criticality assessments of LWR type fuel element shipping packages and similar type systems is described. The experiments were designed to permit easy and accurate definition in Monte Carlo computer codes currently used in these criticality assessments. Basically the experiments were concerned with the critical separation between water flooded subcritical clusters of fuel rods in the presence of various fixed neutron poisons. The experiments were carried out in an 18 m x 3 m x 2.1 m deep tank provided with features specifically designed and built for these experiments. The initial series of experiments are covered in this report and involve aluminum clad 2.35 wt% /sup 235/U enriched UO/sub 2/ rods about 12 mm in diameter by 914 mm in length. The critical separation between three subcritical clusters of these rods aligned in a row was determined with and without the following neutron absorber materials (neutron poisons) located between the clusters: 304L steel with 0, 1.1, and 1.6 wt% boron; boral; copper with 0 and 1 wt% cadmium; cadmium; aluminum; and zircaloy-4. The neutron poisons were in the form of plates slightly larger than the length and width of the opposing faces of the fuel clusters.
Date: October 1, 1977
Creator: Bierman, S.R.; Clayton, E.D. & Durst, B.M.
Partner: UNT Libraries Government Documents Department

Independent verification of a material balance at a LEU fuel fabrication plant. Program for technical assistance to IAEA safeguards

Description: This report describes the application of methodology for planning an inspection according to the procedures of the International Atomic Energy Agency (IAEA), and an example evaluation of data representative of low-enriched uranium fuel fabrication facilities. Included are the inspection plan test criteria, the inspection sampling plans, the sample data collected during the inspection, acceptance testing of physical inventories with test equipment, material unaccounted for (MUF) evaluation, and quantitative statements of the results and conclusions that could be derived from the inspection. The analysis in this report demonstrates the application of inspection strategies which produce quantitative results. A facility model was used that is representative of large low-enriched uranium fuel fabrication plants with material flows, inventory sizes, and compositions of material representative of operating commercial facilities. The principal objective was to determine and illustrate the degree of assurance against a diversion of special nuclear materials (SNM) that can be achieved by an inspection and the verification of material flows and inventories. This work was performed as part of the USA program for technical assistance to the IAEA. 10 figs, 14 tables.
Date: November 1, 1977
Creator: Sorenson, R.J.; McSweeney, T.I.; Hartman, M.G.; Brouns, R.J.; Stewart, K.B. & Granquist, D.P.
Partner: UNT Libraries Government Documents Department