Electrical conductivity of alumina after heavy irradiation in a high-flux fission reactor

The electrical conductivities of seven different alumina specimens were mea sured after they were irradiated in the High-Flux Isotope Reactor (HFIR), O ak Ridge National Laboratory. Results indicated a moderate increase in the electrical conductivity due to the irradiation in HFIR up to 2.8 displaceme nts per atom at 450-500 degreesC. A large offset current was observed in th e irradiated specimens after they were subjected to an applied voltage, whi ch indicated the existence of a large number of trapped electrical charges. An abrupt release of the trapped electrical charges may be a trigger to ca use the previously reported electrical breakdown under irradiation (called radiation-induced electrical degradation).