Radiation damage in silicon carbide, and graphite for fusion reactor first wall applications

Silicon carbide and graphite materials were exposed to fast neutron fluences of 2 x 1023 to 2 X 1024 n/m2 (E > 1 MeV) and a study was made of changes in fracture strength, Weibull modulus and electrical resistivity. Silicon carbide (Norton NC-430) exhibits a decrease in fracture strength (25%) at the higher fluence if the temperature is kept at 298 K, while at 1473 K the decrease in fracture strength is only 10% indicative of recovery due to thermal annealing. The fracture strength of the graphite (POCO AXF-5Q) tested at 298 K increases rapidly by approximately 20% after 2 X 1023n/m2 and remains constant at higher fluence. Analyses of the data using the Weibull weakest link model were given, in addition to annealing and swelling results. (Auth.)