In situ measurement of radiation induced conductivity in oxide insulators during neutron irradiation

An experimental investigation of the in situ electrical conductivity of Wesgo A1995 polycrystalline alumina at approximately 450 °C has been performed at the high flux beam reactor at Brookhaven National Laboratory. The measured radiation induced conductivity (RIC) was about 10^-8 S/m at an ionizing dose rate of 6000 Gy/s. No evidence for permanent radiation induced electrical degradation was observed for an applied electric field of 147 V/mm up to a dose level of ≈ 1.8 displacements per atom. The effect of neutron irradiation on the electrical properties of two mineral insulated cables was also investigated. The RIC in the MgO insulation of a coaxial and a triaxial cable was measured to be in the range of 6-20 × 10^-8 S/m at an ionizing dose rate of ≈ 6000 Gy/s.