726 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 1O22 nvt (E > 50 keV) at 715Β°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"-1450Β°C to 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"-1250Β°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.