Correlation between release of deuterium and annihilation of irradiation defects produced by gamma-ray in Li2TiO3

The dependence of irradiation defect density on hydrogen isotope release behaviors in Li2TiO3 was studied. Li2TiO3 was exposed to gaseous deuterium and, thereafter, gamma-ray irradiation was performed with various gamma-ray doses to change the density of irradiation defects. The deuterium release behavior was measured by TDS. The density of the defects and the state of OD bonds in the sample were elucidated by ESR and FT-IR, respectively. Most of deuterium was adsorbed on the surface or trapped by intrinsic defects after deuterium gas exposure. However, OD bonds were increased as the gamma-ray dose was increased. In addition, the irradiation defects like E-center, O−-center and O2−-center were observed in gamma-ray irradiated samples. This indicated that the density of irradiation defect control the deuterium stable trapping by oxygen. These facts conclude that tritium release temperature will be shifted toward higher temperature as the operation time increased and irradiation defects are accumulated.