TRITIUM EXTRACTION FROM LITHIUM CONTAINING CERAMICS BY THERMAL ANNEALING IN OUT-OF-REACTOR EXPERIMENTS

The present paper shows that thermostimulated extraction of HTO and T2O from lithium ceramics Li4SiO4 proceeds according to two independent mechanisms: (a) the chemidesorption of surface-localized tritiated water (chemical reaction of the first order), and (b) the diffusion of triton to a near-surface layer with subsequent formation of HTO and T2O. The lithium silicates grain growth and increase of imaginary density of pellets influences to tritium diffusion in the grain volume. It was established that the change in the concentration of radiation-induced defects considerably affects the tritiated water releasing processes from lithium ceramics. This paper discusses the effect of chemisorbed water and the content of Fe3+ on the process of tritium thermoextraction.