Helium mobility in advanced nuclear ceramics

The techniques of ion implantation and nuclear reaction depth profiling are used to measure helium migration parameters under thermal ageing in advanced nuclear ceramics such as TiC, ZrC and TiN. Helium release measurements and activation energy calculations have been carried out in the temperature range of 1000–1600 °C for time periods of 2 h. Activation energy values are obtained in the range 0.7–1.2 eV. Due to rare availability of stoichiometric samples, the trapping of He in native vacancies seems to affect the mobility of He. Blisters are observed only at the surface of ZrC on thermal annealing.