Radiation induced conductivity of ceramic coating materials under 14 MeV neutron irradiation

Irradiation with 14 MeV neutrons was performed on ceramic coating materials developed for V/Li blanket system to examine the electrical insulating properties in a radiation environment. Changes in the electrical conductivity of bulk specimens (Y2O3, CaZrO3, Er2O3, AlN and CaZr0.95Sc0.05O3) and coated specimens (stainless steel coated with AlN and Y2O3) were examined at room temperature by leakage current measurements under irradiation. Radiation induced conductivities of the bulk and coated specimens were 3.1 × 10−11–1.3 × 10−10 and 6.3 × 10−12–1.9 × 10−11 S/m for dose rate of 0.01 Gy/s, respectively. The values were the same level or one order higher compared with Al2O3 bulk specimens evaluated by previous experiments with various radiation species. The results indicate that the degradation of insulating properties under irradiation were within allowable levels for application to V/Li blanket system in the present experimental condition. Further evaluation is necessary at higher dose rate and higher temperature.