Developing a tritium release model for Li2TiO3 with irradiation-induced defects

The annihilation kinetics of irradiation-induced defects in Li2TiO3 was evaluated by electron spin resonance. The radiation defects were stabilized with increasing defect density by interaction with neighboring defects. Subsequently, the tritium migration model in Li2TiO3 was established by integrating the kinetics of tritium diffusivity in Li2TiO3 crystalline grains, tritium trapping/detrapping at oxygen vacancies and hydroxyl groups, and annihilation of irradiation-induced defects. The contribution of hydrogen isotopes contained in tritium recovery gas was also considered in this model. The model can demonstrate an overall profile of out-of-pile tritium release for Li2TiO3 with various neutron fluences. Tritium release behavior under neutron irradiation was also estimated by the present established model. The tritium inventory increased under high neutron flux because of the continuous generation of tritium trapping sites, and the addition of hydrogen isotopes to the purge gas could reduce the tritium inventory for Li2TiO3.