Tritium Measurement Techniques for Evaluation of Tritium Migration in Fusion Reactor Materials

Abstract

The tritium migration behaviors in lithium titanate (Li₂TiO₃) and lithium-enriched lithium titanate (Li_2+xTiO₃) were investigated by Evolved Gas Analysis (EGA) using proportional counters and liquid scintillation counters. Li_2+xTiO₃ was considered to be a mixture of Li₂TiO₃ and Li₄TiO₄ structures. Tritium release related to the Li₄TiO₄ structure appeared in the tritium EGA spectra for Li_2+xTiO₃. It was clarified from kinetic analysis for the isothermal tritium release rate that the tritium release behaviors for Li_2+xTiO₃ were found to be controlled by the diffusion process in the Li₂TiO₃ structure. On the other hand, the defective structure and/or structure boundary induced by the Li₄TiO₄ structure would rerain tritium diffusivity in Li_2+xTiO₃.