Electrical degradation of ceramic insulators due to dynamic irradiation effects

Degradation of electrical insulating ability of ceramic insulators is attracting keen attention especially in fusion reactor developments. A permanent increase of the electrical conductivity of the ceramic insulators has been observed recently in certain irradiation conditions, which is called the radiation induced electrical degradation (RIED). Its nature and mechanism are still controversial, but recent experimental results are confirmative to support the existence of the phenomenon causing the degradation of the bulk electrical conductivity of some ceramic insulators under certain irradiation conditions. The paper will review the recent experimental results and discuss the nature and the mechanism of the degradation.