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Interaction of noble-metal fission products with pyrolytic silicon carbide

Description: Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain layers of pyrolytic carbon and silicon carbide, which act as a miniature pressure vessel and form the primary fission product barrier. Of the many fission products formed during irradiation, the noble metals are of particular interest because they interact significantly with the SiC layer and their concentrations are somewhat higher in the low-enriched uranium fuels currently under consideration. To study fission product-… more
Date: January 1, 1982
Creator: Lauf, R. J. & Braski, D. N.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Some Scoping Experiments for a Space Reactor

Description: Some scoping experiments were performed to evaluate fuel performance in a lithium heat pipe reactor operating at a nominal 1500K heat pipe temperature. Fuel-coolant and fuel-coolant-clad relationships showed that once a failed heat pipe occurs temperatures can rise high enough so that large concentrations of uranium can be transported by the vapor phase. Upon condensation this uranium would be capable of penetrating heat pipes adjacent to the failed pipe. The potential for propagation of failur… more
Date: July 7, 1983
Creator: Alexander, C. A. & Ogden, J. S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Performance potential of (Th,U) carbide and (Th,U) nitride fuel in 1200 MWe LMFBR's

Description: An evaluation of the performance potential of thorium-uranium carbide and nitride fuel in 1200 MW(e) homogeneous and heterogeneous LMFBR's has been completed. Comparisons were done with 9.40 mm outer diameter, 0.38 mm cladding fuel pins at a selected peak (3 sigma) linear power of 98.4 kW/m for all cores. Breeding ratios for the homogeneous (Th,U)C and (Th,U)N cores are 1.12 and 1.16, respectively. In the heterogeneous cores the breeding ratios are 0.08 to 0.09 greater. A comparative breeding r… more
Date: April 1, 1978
Creator: Caspersson, S. A. & Kulwich, M. R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Tests of a Higgins contactor for the engineering-scale resin loading of uranium

Description: The loading of uranium on weak-acid ion exchange resin is a basic step in the production of fuel particles for high-temperature gas-cooled reactors (HTGRs). In the work reported here, an engineering-scale continuous resin loader (2-in.-ID Higgins contactor) was tested with existing engineering-scale process equipment. The Higgins contactor was first successfully used to convert Na/sup +/-form resin to the H/sup +/-form; then it was evaluated as a uranium loader. Results show that the 2-in.-ID H… more
Date: January 1, 1978
Creator: Spence, R. D. & Haas, P. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Fuel systems for compact fast space reactors

Description: About 200 refractory metal clad ceramic fuel pins have been irradiated in thermal reactors under the 1200 K to 1550 K cladding temperature conditions of primary relevance to space reactors. This paper reviews performance with respect to fissile atom density, operating temperatures, fuel swelling, fission gas release, fuel-cladding compatibility, and consequences of failure. It was concluded that UO/sub 2/ and UN fuels show approximately equal performance potential and that UC fuel has lesser po… more
Date: December 1, 1983
Creator: Cox, C.M.; Dutt, D.S. & Karnesky, R.A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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HTGR fuels and core development program. Quarterly progress report for the period ending November 30, 1977. [Graphite and fuel irradiation; fission product release]

Description: The work reported here includes studies of basic fission product transport mechanisms, core graphite development and testing, and the development and testing of recyclable fuel systems. Materials studied include irradiation capsule tests of both fuel and graphite. Experimental procedures and results are discussed and data are presented.
Date: December 1, 1977
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Gas-cooled reactor programs: High-Temperature Gas-Cooled Reactor Base-Technology Program. Annual progress report for period ending December 31, 1979

Description: Progress in HTGR studies is reported in the following areas: HTGR chemistry; fueled graphite development; prestressed concrete pressure vessel development; structural materials; HTGR graphite studies; and evaluation of the pebble-bed HTR.
Date: July 1, 1980
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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HTGR Fuels and Core Development Program. Quarterly progress report for the period ending August 31, 1977. [Graphite and fuel irradiation; fission product release]

Description: The work reported includes studies of reactions between core materials and coolant impurities, basic fission product transport mechanisms, core graphite development and testing, the development and testing of recyclable fuel systems, and physics and fuel management studies. Materials studies include irradiation capsule tests of both fuel and graphite. Experimental procedures and results are discussed and data are presented.
Date: September 1, 1977
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Preparation of carbide-type, advanced LMFBR fuel pellets for irradiation testing

Description: A carbothermic reduction process was established to fabricate single- and two-phase uranium-plutonium carbide fuel on a production basis. Sintering temperatures of 1550 and 1800/sup 0/C were used to prepare fuel densities of 98, 87, and 81% of theoretical.
Date: June 1, 1980
Creator: Gutierrez, R. L. & Herbst, R. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Head-end reprocessing studies with irradiated high temperature gas-cooled reactor (HTGR) fuels

Description: Fifty (U-2.75 Th)C/sub 2/ and ThC/sub 2/ coated-particle fuel rods irradated in Peach Bottom were crushed and burned. The fertile and fissile fractions were separated using Thorex reagent and chemical analyses conducted for carbon, heavy metals, and fission products. Results were generally consistent with predictions, indicating that the reprocessing of TRISO-BISO fuel can be accomplished by the proposed flowsheet steps of crushing, fluidized-bed burning, coated particle separation and crushing… more
Date: January 1, 1980
Creator: Fitzgerald, C.L. & Vaughen, V.C.A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Measurement of the enthalpy and specific heat of a Be/sub 2/C-graphite-UC/sub 2/ reactor fuel material to 1980/sup 0/K

Description: The enthalpy and specific heat of a Be/sub 2/C-graphite-UC/sub 2/ composite nuclear fuel material were measured over the temperature range 300 to 1980/sup 0/K using differential scanning calorimetry and liquid argon vaporization calorimetry. The fuel material measured was developed at Sandia National Laboratories for use in pulsed test reactors. The material is a hot-pressed composite consisting of 40 vol % Be/sub 2/C, 49.5 vol % graphite, 3.5 vol % UC/sub 2/ and 7.0 vol % void. The specific he… more
Date: January 1, 1980
Creator: Roth, E.P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Review of some past and present powder metallurgy programs at the Los Alamos Scientific Laboratory

Description: Powder metallurgy programs at LASL are reviewed. Topics covered include: KlWl reactor fuel elements; Phoebus reactor fuel elements, criticality control and poison plate material, structural composites for fuel element supports, and heat shields for fuel element supports; thermionic emitter reactor uranium carbide--zirconium carbide fuel pins, and molybdenum--uranium oxide fuel pins; laser and electron beam fusion targets; and current work in MHD components. (GHT)
Date: January 1, 1977
Creator: Sheinberg, H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Development of a Pneumatic Transfer System for HTGR Recycle Fuel Particles

Description: In support of the High-Temperature Gas-Cooled Reactor (HTGR) Fuel Refabrication Development Program, an experimental pneumatic transfer system was constructed to determine the feasibility of pneumatically conveying pyrocarbon-coated fuel particles of Triso and Biso designs. Tests were conducted with these particles in each of their nonpyrophoric forms to determine pressure drops, particle velocities, and gas flow requirements during pneumatic transfer as well as to evaluate particle wear and br… more
Date: February 1, 1978
Creator: Mack, J. E. & Johnson, D. R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Failure analysis of carbide fuels under transient overpower (TOP) conditions. [LMFBR]

Description: The failure of carbide fuels in the Fast Test Reactor (FTR) under Transient Overpower (TOP) conditions has been examined. The Beginning-of-Cycle Four (BOC-4) all-oxide base case, at $.50/sec ramp rate was selected as the reference case. A coupling between the advanced fuel performance code UNCLE-T and HCDA Code MELT-IIIA was necessary for the analysis. UNCLE-T was used to determine cladding failure and fuel preconditioning which served as initial conditions for MELT-III calculations. MELT-IIIA … more
Date: June 1, 1980
Creator: Nguyen, D.H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Initial stage restructuring in sphere-pac mixed-carbide fuel. [LMFBR]

Description: The analysis of sintering models and mechanisms for mixed-carbide sphere-pac fuel has shown that volume diffusion is the dominant mechanism. The actual diffusion path is not clearly defined but the importance of small pressures in increasing neck growth is apparent. The time dependence of the neck ratios indicates that significant restructuring occurs within 5.6 hours which may be used as a bench mark for the beginning of pore migration.
Date: January 1, 1979
Creator: Guenther, R. J. & Peddicord, K. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Gas-cooled reactor programs: high-temperature gas-cooled reactor technology development program. Annual progress report for period ending December 31, 1981

Description: Information is presented concerning HTGR chemistry; fueled graphite development; irradiation services for General Atomic Company; prestressed concrete pressure vessel development; HTGR structural materials; graphite development; high-temperature reactor physics studies; shielding studies; component flow test loop studies; core support performance test; and application and project assessments.
Date: June 1, 1982
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Thermophysical properties of thorium and uranium systems for use in reactor safety analysis

Description: The data compilation is intended to serve as a preliminary set of thermophysical property values for use in reactor safety analyses of the Th--/sup 233/U reactor concept. The properties covered include mp, bp, enthalpy, heats of vaporization and fusion, heat capacity, thermal conductivity, density, thermal expansion, emissivity, viscosity, etc. The systems covered are Th, Th/sub 0/./sub 9/U/sub 0/./sub 1/, U, ThO/sub 2/, Th/sub 0/./sub 9/U/sub 0/./sub 1/O/sub 2/, UO/sub 2/, U/sub 0/./sub 8/Pu/s… more
Date: June 1, 1977
Creator: Fink, J.K.; Chasanov, M.G. & Leibowitz, L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Thermal conductivities of mixed carbide fuel and blanket materials. [LMFBR]

Description: Measurement of the thermal and electrical transport properties of the uranium-plutonium carbides began in 1950, the bulk of the experimental work being performed in the US, UK, and France. During 1974 and 1975, as part of the national LMFBR program effort to provide unified design parameters, a series of critical reviews on the thermodynamic, physical, chemical, and mechanical properties of uranium-plutonium carbide (and nitride) fuels was prepared by authors at several US laboratories. Propert… more
Date: May 1, 1980
Creator: Lewis, H. D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Licensing topical report: the measurement and modelling of time-dependent fission product release from failed HTGR fuel particles under accident conditions

Description: The release of fission products from failed fuel particles was measured under simulated accident (core heatup) conditions. A generic model and specific model parameters that describe delayed fission product release from the kernels of failed HTGR fuel particles were developed from the experimental results. The release of fission products was measured from laser-failed BISO ThO/sub 2/ and highly enriched (HEU) TRISO UC/sub 2/ particles that had been irradiated to a range of kernel burnups. The b… more
Date: April 1, 1980
Creator: Myers, B.F. & Morrissey, R.E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Fission product Pd-SiC interaction in irradiated coated particle fuels

Description: Silicon carbide is the main barrier to fission product release from coated particle fuels. Consequently, degradation of the SiC must be minimized. Electron microprobe analysis has identified that palladium causes corrosion of the SiC in irradiated coated particles. Further ceramographic and electron microprobe examinations on irradiated particles with kernels ranging in composition from UO/sub 2/ to UC/sub 2/, including PuO/sub 2 -x/ and mixed (Th, Pu) oxides, and in enrichment from 0.7 to 93.0… more
Date: April 1, 1980
Creator: Tiegs, T. N.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Failure experience in refractory alloy-clad fuel pins applicable to space nuclear power

Description: Numerous in-reactor tests were conducted in the 1960's and early 1970's to develop fuel elements for space nuclear reactors. Most of the tests emphasized refractory metal-clad UN, UC, and UO/sub 2/. Previous reviews were provided by Weaver and Scott and by Gluyas and Watson. More recently, these data were reviewed for supporting information concerning the technical feasibility issues as they relate to the current reactor designs. This paper will focus on the fuel pin failure experience to obtai… more
Date: May 1, 1984
Creator: Dutt, D.S. & Cox, C.M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Status of steady-state irradiation testing of mixed-carbide fuel designs. [LMFBR]

Description: The steady-state irradiation program of mixed-carbide fuels has demonstrated clearly the ability of carbide fuel pins to attain peak burnup greater than 12 at.% and peak fluences of 1.4 x 10/sup 23/ n/cm/sup 2/ (E > 0.1 MeV). Helium-bonded fuel pins in 316SS cladding have achieved peak burnups of 20.7 at.% (192 MWd/kg), and no breaches have occurred in pins of this design. Sodium-bonded fuel pins in 316SS cladding have achieved peak burnups of 15.8 at.% (146 MWd/kg). Breaches have occurred in h… more
Date: January 1, 1983
Creator: Harry, G.R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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