Evaluation of insulating property of ceramic materials for V/Li blanket system under fission reactor irradiation

Abstract

To examine radiation effects on electrical insulating performance of candidate ceramic materials developed for the V/Li blanket system, in situ conductivity measurements for bulk specimens of Y 2O 3, CaZrO 3 and Er 2O 3 were carried out during irradiation with fission neutrons in JMTR (Japan Material Testing Reactor). Evaluated radiation induced conductivities (RIC) of the specimens were 5.2 × 10 −9 S/m for Y 2O 3 at ∼8 Gy/s (50 °C), 1.8 × 10 −8 S/m for CaZrO 3 at ∼40 Gy/s (35 °C) and 2.1 × 10 −8 S/m for Er 2O 3 at ∼50 Gy/s (45 °C), respectively. The present results were consistent with the values extrapolated from the previous data obtained by DT neutron irradiations at low dose rate of up to ∼0.1 Gy/s. The flux dependence of the data indicates that RIC of the candidate ceramics with different radiation species could be well correlated using Gy/s as a parameter. The present results showed that the electrical degradation due to RIC will not prevent the achievement of required insulating performance for the blanket system.