Evaluation of Li mass loss from Li₂TiO₃ with excess Li pebbles in water vapor atmosphere

Highlights: • Li mass loss of Li₂TiO₃ with excess Li pebbles was investigated. • The Li mass loss with a relatively high rate was limited even in 50 Pa H₂O/Ar at 900 °C. • The Li mass loss rate increased with increasing temperature. • The Li mass loss rate increased proportionally to a square root of water vapor pressure. • An empirical formula for evaluating the Li mass loss was proposed. - Abstract: Understanding of Li mass transfer behavior in a tritium breeding blanket is an important issue from viewpoints of establishment of tritium cycle and tritium safety. In this work, weight reduction property of Li₂TiO₃ with excess Li pebbles, which were fabricated by National Institutes for Quantum and Radiological Science and Technology, was investigated and the amount of Li mass loss and the rate of Li mass loss in water vapor atmosphere at elevated temperatures were evaluated. The Li mass loss proceeding at 900 °C with a relatively high rate was limited. The Li mass loss of Pebble210 (Li/Ti = 2.10) was 1.2 wt% and that of Pebbe211 (Li/Ti = 2.11) was 1.4 wt%, eventually. The rate of the Li mass loss increased with increasing temperature and it seemed to increase proportionally to a square root of water vapor pressure. An empirical formula for the Li mass loss was proposed as a function of temperature, heating time and water vapor pressure in a purge gas.