In-situ Electrical Resistivity Measurement of MgOcentre dotAl_2O_3 Coating under Neutron Irradiation

摘要

Ceramic coatings on the surface of structural materials such as 316SS have been considered for electrical insulators and tritium permeation barriers in fusion reactor designs. MgOcentre dotAl_2O_3is one of the most promising materials as a coating material from a point of high electrical resistivity and so on. In this report, the electrical resistivity of a MgOcentre dotAl_2O_3 coating on 316SS was investigated under neutron irradiation with the JMTR (Japan Materials Testing Reactor) by in-situ electrical resistivity measurement. The specimen was irradiated at 360deg C in a He atmosphere. Radiation Induced Conductivity (RIC) was observed at the beginning of reactor. The electrical resistivity of the coating before neutron irradiation decreased from 1 X 10~11OMEGAcentre dot cm to 2 X 10~8 OMEGAcentre dotcm with increase reactor power. The electrical resistivity of the coating under neutron irradiation decreased again from 2 X 10~8 OMEGAcentre dot cm to 5 X 10~4 OMEGAcentre dot cm above 1 X 10~19 n/cm~2 (En>1 MeV). It did not recover up to unirradiated level. The electrical resistivity of the coating after neutron irradiation was about 2 X 10~6 OMEGAcentre dot cm. It was clear that Radiation Induced Electrical Ddgradation (RIED) in the MgOcentre dotAl_2O_3 coating was recognized above a fluence of about 1 X 10~20 n/cm~2 (En>1MeV).