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108. Irradiation of graphite in HFIR
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CARBON
108. Irradiation of graphite in HFIR* C. R. Kennedy (Metals and Ceramics i&&ion, Oak Ridge National Laboratory, Oak Ridge, Tennessee). Fifteen different grades of graphite have been irradiated in the High Flux Isotope Reactor to ffuences up to Z-5 X 1O22nvt (E > 50 keV) at 715°C. The dimensional instability of the graphite is analyzed with respect to fabrication variables. Major emphasis is placed upon the volumetric changes in the graphite. *Research sponsored by the U.S. Atomic Energy Commission under contract with the Union Carbide Corporation. 109. Ra~a~on-induced parabok graphite distortions* W. P. Eatheriy (Oak Ridge ~at~~~~aborato~, Oak Ridge, Tennessee). For a large set of nuclear graphites, the radiation-induced volumetric distortion can be described in terms of a function quadratic influence, but linear in temperature parameters. This behavior and its consequences to reactor design will be discussed. *Research sponsored by the U.S. Atomic Energy Commission under contract with the Union Carbide Corporation. 110. Irradiation behavior of anisotropic and near-isotropic graphites at 1000”-1450°Cto 10% n/cm2* G. B. Engle (Gulf General Atomic, Inc., San Diego, Calijborrsia). A series of anisotropic or near-isotropic graphites fabricated with needle coke, Gilsonite, or uncalcined petroleum coke has been irradiated at lOOO”-1250°C to 10”2n/cm2. Changes in dimensions, thermal expansivity, apparent density and porosity were measured on bulk specimens and densitometric separations were performed on irradiated specimens that were ground to fine particles. Correlations between the dimensiona and property changes and structural features will be presented. *Work supported by the U.S. Atomic Energy Commission, Contract At(O4-3)-167Project Agreements No. 12 and 17. 111. The irradiation behavior of POCO graphites A. L. Pitner (Pa&$ worthiest ~~~~, ~at~~~ Magi I~t~t~te, ~~h~~, W~hi~gto~). Seven grades of POLO graphite were irradiated at temperatures up to 1300°C and some samples accumulated an exposure of 1.2 X 1O22nvt (E > 0.18 MeV). All grades behaved isotropically and generally showed markedly improved dimensional stability over conventional graphites. Micrographs of one grade (unirradiated) show a structure considerably different from that of conventional graphites. 112. Dime&onal and physical property changes of H.T.R. graphites irradiated at temperatures in the range ~a-lZ~oC M. R. Everett, R. Blackstone, L. W. Graham and R. Manzel (O.E.C.D. Dragon Project, A.E.E. Winjidh, Dorchester, Dorset, U.K.). A range of graphites selected for possible utilisation in High Temperature Reactors has been irradiated in the Dragon Reactor at Winfrith and the High Flux Reactor at Petten. Fast neutron dose correlation work is described and data presented on changes in dimensions, Young’s Modulus, electrical resistivity, and thermal expansion coefficient for fast neutron doses of up to 5 X I@’ n/ cm-* nickel dose Dido equivalent. 113. Anisotropy determinations of potential nuclear graphites* 0. B. Cavin (Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee). Quantitative determinations of anisotropy values of potential polycrystalline nuclear graphites have been done with semiautomated X-ray diffraction equipment. By use of the double integration as defined by R=
Lm’* &-‘I Z( # ) sin3q)d4dfi]/[
r,“” ~~“Z(~)sindd#dS]
one can determine the anisotropy relative to any known direction in the material. The usefulness of these ‘R’ values in the interpretation of radiation effects in these materials will be indicated. *Research sponsored by the U.S. Atomic Energy Commission under contract with the Union Carbide Corporation. 114. ‘Radiation-sensitive’ &Fe&s in graphites A. R. Ubbelohde (Department of Chemical Enginem’ng, stract not submitted.
Imperial College, London, SW 7, U.K.). Short ab-
CARBON
108. Irradiation of graphite in HFIR* C. R. Kennedy (Metals and Ceramics i&&ion, Oak Ridge National Laboratory, Oak Ridge, Tennessee). Fifteen different grades of graphite have been irradiated in the High Flux Isotope Reactor to ffuences up to Z-5 X 1O22nvt (E > 50 keV) at 715°C. The dimensional instability of the graphite is analyzed with respect to fabrication variables. Major emphasis is placed upon the volumetric changes in the graphite. *Research sponsored by the U.S. Atomic Energy Commission under contract with the Union Carbide Corporation. 109. Ra~a~on-induced parabok graphite distortions* W. P. Eatheriy (Oak Ridge ~at~~~~aborato~, Oak Ridge, Tennessee). For a large set of nuclear graphites, the radiation-induced volumetric distortion can be described in terms of a function quadratic influence, but linear in temperature parameters. This behavior and its consequences to reactor design will be discussed. *Research sponsored by the U.S. Atomic Energy Commission under contract with the Union Carbide Corporation. 110. Irradiation behavior of anisotropic and near-isotropic graphites at 1000”-1450°Cto 10% n/cm2* G. B. Engle (Gulf General Atomic, Inc., San Diego, Calijborrsia). A series of anisotropic or near-isotropic graphites fabricated with needle coke, Gilsonite, or uncalcined petroleum coke has been irradiated at lOOO”-1250°C to 10”2n/cm2. Changes in dimensions, thermal expansivity, apparent density and porosity were measured on bulk specimens and densitometric separations were performed on irradiated specimens that were ground to fine particles. Correlations between the dimensiona and property changes and structural features will be presented. *Work supported by the U.S. Atomic Energy Commission, Contract At(O4-3)-167Project Agreements No. 12 and 17. 111. The irradiation behavior of POCO graphites A. L. Pitner (Pa&$ worthiest ~~~~, ~at~~~ Magi I~t~t~te, ~~h~~, W~hi~gto~). Seven grades of POLO graphite were irradiated at temperatures up to 1300°C and some samples accumulated an exposure of 1.2 X 1O22nvt (E > 0.18 MeV). All grades behaved isotropically and generally showed markedly improved dimensional stability over conventional graphites. Micrographs of one grade (unirradiated) show a structure considerably different from that of conventional graphites. 112. Dime&onal and physical property changes of H.T.R. graphites irradiated at temperatures in the range ~a-lZ~oC M. R. Everett, R. Blackstone, L. W. Graham and R. Manzel (O.E.C.D. Dragon Project, A.E.E. Winjidh, Dorchester, Dorset, U.K.). A range of graphites selected for possible utilisation in High Temperature Reactors has been irradiated in the Dragon Reactor at Winfrith and the High Flux Reactor at Petten. Fast neutron dose correlation work is described and data presented on changes in dimensions, Young’s Modulus, electrical resistivity, and thermal expansion coefficient for fast neutron doses of up to 5 X I@’ n/ cm-* nickel dose Dido equivalent. 113. Anisotropy determinations of potential nuclear graphites* 0. B. Cavin (Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee). Quantitative determinations of anisotropy values of potential polycrystalline nuclear graphites have been done with semiautomated X-ray diffraction equipment. By use of the double integration as defined by R=
Lm’* &-‘I Z( # ) sin3q)d4dfi]/[
r,“” ~~“Z(~)sindd#dS]
one can determine the anisotropy relative to any known direction in the material. The usefulness of these ‘R’ values in the interpretation of radiation effects in these materials will be indicated. *Research sponsored by the U.S. Atomic Energy Commission under contract with the Union Carbide Corporation. 114. ‘Radiation-sensitive’ &Fe&s in graphites A. R. Ubbelohde (Department of Chemical Enginem’ng, stract not submitted.
Imperial College, London, SW 7, U.K.). Short ab-