Irradiation behaviors of nuclear grade graphite in commercial reactor, 2

Thermal conductivity, electrical resistivity and stored energy were measured for Pechiney nuclear grade graphite irradiated in the temperature range 220--4000C up to the maximum neutron fluence 2.2x1020n/cm2(E>0.85MeV) in the environment of a carbon dioxide in a commercial reactor. Thermal conductivity decreased, electrical resistivity and stored energy increased owing to neutron irradiation and their changes were larger for the samples irradiated at lower temperatures. A linear relation between stored energy and fractional change in thermal resistivity was obtained for the irradiated samples and it was found that its proportional constant is about two times of that reported previously. The relation between thermal conductivity and electrical resistivity is discussed for irradiated samples as well. (author)