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Remote fabrication of nuclear fuel pellets

Description: The equipment for remote fabrication of pellet fuels is in various stages of design, testing and evaluation. A pellet gaging system specifically designed to be maintained remotely has been demonstrated and is currently being interfaced with a programmable electro-mechanical manipulator to demonstrate completely automatic and remote disassembly and reassembly of the inspection unit. Pulsed magnetic welding of fuel rod end closures have been demonstrated. The solid-state welding technique allows the use of ultrasonics for weld inspection in place of traditional x-radiography. This welding and inspection method provides an attractive alternative for remote fuel fabrication. A new batch sintering furnace concept based upon aerospace technology is being developed. The furnace will have five to ten times the through-put of conventional batch furnaces and is easier to maintain than the horizontal furnaces in use today. Two high-speed mechanical press concepts (anvil and rotary) are currently being evaluated for remote operation and maintenance. The anvil press is especially attractive for remote fabrication due to its simplicity in set up and die change methods. All pellet fuel fabrication operations will be developed for remote operation and maintenance and representative fabrication rates will be demonstrated.
Date: June 1, 1978
Creator: Nyman, D.H.; Dahl, R.E. & Claudson, T.T.
Partner: UNT Libraries Government Documents Department

Automated inspection of nuclear fuel pellets

Description: The evolutionary development of the automated fuel pellet inspection system has involved several man years of effort and the testing of five different engineering prototypes. Experience gained from the process testing of this latest generation of the automated fuel pellet gaging system will be used to design and build a production unit which is completely automated and can be maintained remotely.
Date: April 1, 1979
Creator: McLemore, D. R.; Wilks, R. S.; Nyman, D. H. & Brady, R. M.
Partner: UNT Libraries Government Documents Department

Automated in-line measurement of nuclear fuel pellets

Description: HEDL is currently developing, fabricating, and evaluating automated fuel fabrication equipment with the goals of reduced personnel exposure, improved safeguards/accountability and improved fuel performance. One of the automated equipment items which has been fabricated is a fuel pellet inspection system. This system inspects fuel pellets for surface flaws and measures pellets for length, diameter, and weight at a rate of one pellet per second. The inspected pellets are sorted automatically and the results of the inspection are transmitted to a central computer for trend analysis and verification of accountability data. 11 figures.
Date: January 1, 1979
Creator: McLemore, D. R. & Nyman, D. H.
Partner: UNT Libraries Government Documents Department

A limited human factors engineering assessment of the 242-A Evaporator system: For input to the Safety Class 2 Systems/Structure assessment

Description: Prior to the startup of the 242-A Evaporator system, members of the Pacific Northwest Laboratory (PNL) Human Factors Engineering staff conducted an assessment of the controls and monitors related to the issues classified as Safety Class 2 Systems/Structures. The purpose of this assessment was to determine the adequacy of the controls and monitors in ensuring safe operations of the Evaporator system, and the results were described in a Letter Report dated April 5, 1991. The ensuing comments/recommendations of Westinghouse Hanford Company operations, safety, and management personnel formed the basis of additional human factors activities that resulted in this report. 4 refs.
Date: October 1, 1991
Creator: Schur, A.; Hunt, S.T. & Pond, D.J.
Partner: UNT Libraries Government Documents Department

Nuclear criticality safety of the fuel element fabrication facility at Attleboro, Massachusetts

Description: The Attleboro Facility produces fuel elements for the ORR and the HFIR reactors at the Oak Ridge National Laboratory and for the HFBR reactor at the Brookhaven National Laboratory. It is proposed to utilize the criticality indicator system (CI) as a method for nuclear criticality control at the Attleboro fuel element fabrication facility. Application of the method requires an evaluation be made of the effect of hydrogenous moderation on the potential neutron multiplication factor of operations. Analyses are given which confirm the applicability of the CI system under credible normal and possible abnormal contingencies. It is also shown that no significant neutron multiplication occurs during normal operations and that a k/sub eff/ not exceeding 0.5 may be expected for abnormal conditions.
Date: June 1, 1978
Creator: Thomas, J.T.
Partner: UNT Libraries Government Documents Department

Radiological source terms resulting from sabotage to transportation casks: Final report

Description: The Nuclear Regulatory Commission (NRC) promulgated a rule, 10 CFR 73.37, which established requirements for safeguarding shipments of spent fuel to reduce the risk from acts of sabotage of highly radioactive materials. After the rule became effective, experimental programs conducted by Battelle for the NRC and by Sandia for the DOE showed the consequences of an attack using explosives on a shipment of PWR spent fuel were significantly less than had been indicated by earlier analytical studies. As a result, NRC is considering modifying the safeguards requirements. In support of NRC's efforts to modify the rule, Battelle has conducted additional experimental studies to evaluate the consequences of attacks on shipments of high-temperature gas-cooled reactor (HTGR) spent fuel, nonpower reactor (NPR) spent fuel, and vitrified high-level waste (HLW). Model casks containing surrogates of the spent fuels or high-level waste were penetrated by the jet from a precision shaped charge. Air samples collected after each test were used to estimate the quantities of respirable material released after the cask was penetrated. Results of the tests were scaled by specially developed scaling factors to estimate the releases that may occur from attacks on full-sized shipments of the materials. It was concluded that the sabotage of shipments of HTGR spent fuel, NPR spent fuel, or vitrified HLW should have no greater consequences than those predicted for shipments of PWR spent fuel.
Date: November 1, 1986
Creator: Miller, N E; Fentiman, A W; Kuhlman, M R; Ebersole, H N; Trott, B D & Orban, J E
Partner: UNT Libraries Government Documents Department

Partial thermal denitration of uranyl nitrate solutions in a screw denitrator

Description: Weak-acid ion exchange resin is loaded with uranium by acid-deficient uranyl nitrate solutions that have a nitrate uranium ratio of about 1.6. Processing this solution from an acid-excess uranyl nitrate solution by thermal denitration in a screw denitrator is described. Direct processing of this solution resulted in an insufficient acid deficiency of about C/sub N//C/sub U/ = 1.8. Therefore, the process was modified; a highly denitrated UO/sub 3/ slid was processed with C/sub N//C/sub U/ = 0.2, and this solid was subsequently dissolved to prepare acid-deficient uranyl nitrate solution or slurry. A detailed flowsheet for this process is given. The proposed combined screw denitrator-dissolver unit may meet the process requiements with improved efficiency.
Date: August 1, 1978
Creator: Ringel, H.D. & Haas, P.A.
Partner: UNT Libraries Government Documents Department

Development of nuclear fuel microsphere handling techniques and equipment

Description: Considerable progress has been made in the development of microsphere handling techniques and equipment for nuclear applications. Work at Oak Ridge National Laboratory with microspherical fuel forms dates back to the early sixties with the development of the sol-gel process. Since that time a number of equipment items and systems specifically related to microsphere handling and characterization have been identified and developed for eventual application in a remote recycle facility. These include positive and negative pressure transfer systems, samplers, weighers, a blender-dispenser, and automated devices for particle size distribution and crushing strength analysis. The current status of these and other components and systems is discussed.
Date: January 1, 1980
Creator: Mack, J.E.; Suchomel, R.R. & Angelini, P.
Partner: UNT Libraries Government Documents Department

Models for gamma-ray holdup measurements at duct contact

Description: The use of gamma-ray measurements to nondestructively assay special nuclear material holdup in DOE processing facilities has increased recently. A measurement approach that is relatively insensitive to deposit geometry involves withdrawing the detector from the holdup-bearing equipment far enough to validate an assumed point-, line-, or area-source deposit geometry. Because of facility constraints, these generalized geometry procedures are not always followed, and some ducts are measured at contact. Quantitative interpretation of contact measurements requires knowledge of the width of the deposit transverse to the duct axis. Rocky Flats personnel have introduced a method to obtain data from which this width can be deduced. It involves taking measurements in pairs, with the detector viewing the holdup deposit at contact from above and below the duct. The interpretation of the top and bottom measurements to give the deposit width at each location requires a model for the detector's response to radial source position and a model for the deposit geometry. We have derived a relationship between the top-to-bottom count rate ratio and the deposit width that approximates the detector response and models the deposit geometry as a uniform strip. The model was validated in controlled experiments that used thin foils of high-enriched uranium metal to simulate duct deposits. 4 refs., 5 figs., 1 tab.
Date: January 1, 1991
Creator: Sheppard, G.A.; Russo, P.A.; Wenz, T.R.; Miller, M.C.; Piquette, E.C. (Los Alamos National Lab., NM (United States)); Haas, F.X. et al.
Partner: UNT Libraries Government Documents Department

Thoria development activities. Annual report, fiscal year 1978

Description: Pacific Northwest Laboratory's (PNL) ThO/sub 2/ development activities for FY-1978 are reviewed. These activities are in support of the FRAD (Fuels Refabrication and Development) program's goal of developing proliferation resistant fuel cycles. Included are results for the five ThO/sub 2/ fuel related elements that are assigned to PNL. During FY-1978, work on these elements has been directed primarily toward establishing the TOFDL (Thorium Oxide Fuel Development Laboratory) facility where unit operations for ThO/sub 2/-based fuels will be defined and fuels for test irradiations fabricated. Additional activities include evaluation of ThO/sub 2/ powders derived by various oxalate precipitation conditions, the fabricability of commercially available ThO/sub 2/ powders, hybrid pellet fuel fabrication and definition of an irradiation test plan.
Date: February 1, 1979
Creator: Hart, P.E.
Partner: UNT Libraries Government Documents Department

Optimization of thorium oxalate precipitation conditions relative to thorium oxide sinterability

Description: The effect of thorium oxalate precipitation conditions on derived oxide sinterability was investigated with the objective of producing ThO/sub 2/ powder that could be sintered to high density without premilling. Precipitation conditions examined were temperature, digestion time and agitation method which were employed in a two-level factorial experimental design to delineate their effects. The two levels for each of the factors, respectively, were 10/sup 0/C and 70/sup 0/C, 15 min and 360 min, and mechanical stirrer and a homogenizer that imparted both mechanical and ultrasonic agitation. The ThO/sub 2/ derived from each of the precipitation trials was characterized with respect to morphology, surface area, and crystallite size as well as sinterability. Only precipitation temperature had a significant effect upon all the properties of the derived oxide powders.
Date: January 1, 1980
Creator: White, G.D.; Bray, L.A. & Hart, P.E.
Partner: UNT Libraries Government Documents Department

Developing and testing a vertical sintering furnace for remote nuclear applications

Description: Horizontal-type furnaces used to sinter fuel pellets on a production basis are large and thus impractical for remote applications. However, research has shown that vertical-type furnaces are adaptable for use and are cheaper to operate and maintain. In 1979, Pacific Northwest Laboratory, working under the auspices of the Department of Energy's Fuel Refabrication and Development (FRAD) Program, began developing an advanced concept for a remotely operated furnace designed specifically to sinter nuclear fuel pellets. The FRAD Program at PNL ended before the sintering of nuclear fuels could be completely verified. However during 1979, PNL performed a sufficient number and variety of tests to establish that nuclear fuel pellets can be sintered in a vertical furnace.
Date: January 1, 1980
Creator: Nesbitt, J. F. & Ryer, C. M.
Partner: UNT Libraries Government Documents Department

Convective heat exposure from large fires to the final filters of ventilation systems

Description: The Fire Science Group of the Hazards Control Department, Lawrence Livermore Laboratory has been asked to design a probable fire scenario for a fuel-pellet fabrication facility. This model was used to estimate the potential for thermal damage to the final HEPA filters. These filters would not experience direct fire exposure because they are the last component of the ventilation system before the exhaust air pumps. However, they would be exposed to hot air and fire gases that are drawn into the ventilation system. Because fire is one of the few occurrences that can defeat the containment integrity of facilities where radioactive materials are stored and processed, the fire scenarios must be defined to ensure that containment systems are adequate to meet the threat of such events. Fire-growth calculations are based on the measured fuel load of materials within the fabrication enclosure and on semi-empirical fire-spread models. It is assumed that the fire never becomes ventilation controlled. The temperature rise of ceiling gases and heat transfer from ventilation ducting are calculated using accepted empirical relationships, and the analysis shows that even under the most severe exposure conditions, heat transfer from the duct reduces the fire gas temperatures to levels that would not hamper filter function.
Date: August 23, 1979
Creator: Alvares, N.J.
Partner: UNT Libraries Government Documents Department

High speed inspection of ceramic fuels

Description: A fuel pellet inspection system is under development and evaluation for use in the High Performance Fuel Laboratory (HPFL) at Richland, Washington. A major operation in this process is the gaging of fuel pellets for dimensions (length and diameter), surface flaws and weight. The system is modularly designed to simplify maintenance operations thereby reducing personnel exposure. The inspection system is divided into two parts: mechanical and electronic. The mechanical portion consists of a pellet handling system; inspection stations for measuring length, diameter, weight and surface flaws; and a glovebox-like containment which isolates Special Nuclear Material (SNM) from the surrounding environment. The electronic portion is a dedicated minicomputer for process control and a supervisory computer system which will be located in a centralized control center and be shared with other development activities in the HPFL.
Date: March 1, 1979
Creator: McLemore, D. R.
Partner: UNT Libraries Government Documents Department

Simulated physical inventory verification exercise at a mixed-oxide fuel fabrication facility

Description: A physical inventory verification (PIV) was simulated at a mixed-oxide fuel fabrication facility. Safeguards inspectors from the International Atomic Energy Agency (IAEA) conducted the PIV exercise to test inspection procedures under ''realistic but relaxed'' conditions. Nondestructive assay instrumentation was used to verify the plutonium content of samples covering the range of material types from input powders to final fuel assemblies. This paper describes the activities included in the exercise and discusses the results obtained. 5 refs., 1 fig., 6 tabs.
Date: January 1, 1985
Creator: Reilly, D. & Augustson, R.
Partner: UNT Libraries Government Documents Department

Design concepts and advanced telerobotics development for facilities in the back end of the nuclear fuel cycle

Description: In the Fuel Recycle Division at the Oak Ridge National Laboratory, a comprehensive remote systems development program has existed for the past seven years. The new remote technology under development is expected to significantly improve remote operations by extending the range of tasks accomplished by remote means and increasing the efficiency of remote work undertaken. Five areas of the development effort are primary contributors to the goal of higher operating efficiency for major facilities for the back end of the nuclear fuel cycle. These areas are the single-cell concept, the low-flow ventilation concept, television viewing, equipment-mounting racks, and force-reflecting manipulation. These somewhat innovative directions are products of a design process where the technical scenario to be accomplished, the remote equipment to accomplish the scenario, and the facility design to house the equipment, are considered in an iterative design process to optimize performance, maximize long-term costs effectiveness, and minimize initial capital outlay. 14 refs., 3 figs.
Date: January 1, 1987
Creator: Feldman, M.J.
Partner: UNT Libraries Government Documents Department

Thermally activated deformation behavior of polycrystalline UO/sub 2/ above 1800/sup 0/C

Description: Studies on the thermally activated deformation behavior of stoichiometric UO/sub 2/ at temperatures between 1800 and 2000/sup 0/C are discussed. Load-relaxation experiments were conducted at about 5 x 10/sup -6/ Torr; typical behavior at 1900/sup 0/C for UO/sub 2/ of 20 ..mu..m grain size is shown. The behavior is represented mathematically. The variation of load-relaxation rate with load is plotted. The applied-stress exponent of the plastic strain rate was found to be greater than 4.0, a value which suggests that dislocation processes may be responsible for the deformation behavior of UO/sub 2/ samples at T greater than or equal 1800/sup 0/C. The effective stress is the driving force for the dislocations. The values obtained for the effective stress exponent were less than those for the applied stress exponent. The true activation volume was found to be relatively insensitive to temperature; however, significant dependences on the stress were observed. 3 figures. (RWR)
Date: January 1, 1976
Creator: Singh, R. N.
Partner: UNT Libraries Government Documents Department

Plutonium roundtable discussion

Description: The roundtable discussion began with remarks by the chairman who pointed out the complicated nature of plutonium chemistry. Judging from the papers presented at this symposium, he noticed a pattern which indicated to him the result of diminished funding for investigation of basic plutonium chemistry and funding focused on certain problem areas. Dr. G.L. silver pointed to plutonium chemists' erroneous use of a simplified summary equation involving the disproportionation of Pu(EV) and their each of appreciation of alpha coefficients. To his appreciation of alpha coefficients. To his charges, Dr. J.T. Bell spoke in defense of the chemists. This discussion was followed by W.W. Schulz's comments on the need for experimental work to determine solubility data for plutonium in its various oxidation states under geologic repository conditions. Discussion then turned to plutonium pyrachemical process with Dana C. Christensen as the main speaker. This paper presents edited versions of participants' written version. (ATT)
Date: January 1, 1982
Creator: Penneman, R.A.
Partner: UNT Libraries Government Documents Department

Evaluation of methods for seismic analysis of mixed-oxide fuel fabrication plants

Description: Guidelines are needed for selecting appropriate methods of structural analyses to evaluate the seismic hazard of mixed-oxide fuel fabrication plants. This study examines the different available methods and their applicability to fabrication plants. These results should provide a basis for establishing guidelines recommending methods of analysis to ensure safe design against seismic hazards. Using the Westinghouse Recycle Fuels Plant as representative of future mixed-oxide fuel fabrication plants, critical structures and equipment (systems, components, and piping/ducting) were identified. These included the manufacturing building and 11 different pieces of equipment. After examination of the dynamic response characteristics of the building and the different methods available to analyze equipment, appropriate methods of analyses were recommended. Because critical equipment analysis and test methods generally use floor-response spectra as their seismic input loading, several methods used to generate floor spectra were also examined. These include the time-history approach and the Kapur and Biggs approximate methods. The examination included the effect of site characteristics and both horizontal and vertical structural response. (auth)
Date: October 1, 1975
Creator: Tokarz, F.J.; Arthur, D.F. & Murray, R.C.
Partner: UNT Libraries Government Documents Department

High burn-up plutonium isotopic compositions recommended for use in shielding analysis

Description: Isotopic compositions for plutonium generated and recycled in LWR's were estimated for use in shielding calculations. The values were obtained by averaging isotopic values from many sources in the literature. These isotopic values should provide the basis for a reasonable prediction of exposure rates from the range of LWR fuel expected in the future. The isotopic compositions given are meant to be used for shielding calculations, and the values are not necessarily applicable to other forms of analysis, such as inventory assessment or criticality safety. 11 tables, 2 figs.
Date: June 1, 1977
Creator: Zimmerman, M. G.
Partner: UNT Libraries Government Documents Department