Thermal diffusivity of ceramics during a neutron irradiation estimated from post irradiated measurement

In ceramic materials, heat is mainly carried by phonon unlike metals, and neutron irradiated ceramics show severe degradation in thermal diffusivity. But after the irradiation, a thermal diffusivity was changed by measuring temperature, so post irradiation measurements at room temperature do not represent the thermal diffusivity at the irradiation temperature. In this study, thermal diffusivity of heavily neutron-irradiated ceramics was measured at 123-413 K and the dependence on measuring temperature was fixed. Using the temperature at that specimen was irradiated, thermal diffusivity during the irradiation was estimated with several assumptions. (author)