Recovery behavior of point defects after low-dose neutron irradiation of sintered SiC by thermal diffusivity and swelling measurements

Effects of neutron irradiation on physical property change of two kinds of sintered α-SiC ceramics were examined through the post-irradiation recovery experiments. Changes of macroscopic length and thermal diffusivity due to post-irradiation isothermal annealing up to 6 h between room temperature and 1400 °C were measured. Results of both measurements indicated almost same recovery tendency for each specimen. The SiC specimen containing Al2O3 showed large change in the activation energy of both recoveries at ∼950 °C and 1200 °C, and these of the SiC specimen containing B4C showed large change at ∼800 °C, 950 °C and 1200 °C. Activation energies of macroscopic length recovery for both specimens from irradiation temperature to the lower temperature boundary were 0.1–0.2 eV and those of the second temperature range were 0.8–0.9 eV, respectively. These values indicated that the recovery of these properties is proceeded by the recombination of Frenkel pairs of both C and Si at various configurations.