Tritium release behavior from Li2BeF4 molten salt by permeation through structural materials

Tritium permeation through Monel metal and SUS316 contacting with Flibe (Li2BeF4) a potential liquid tritium breeding material was investigated by in-situ tritium release experiment. The permeation rate from Flibe was much larger for HT than that for T+. The overall mass transfer coefficient of HT permeation from Flibe, K2, was 10–50 times smaller than that of HT release from Flibe to the gas phase, K1. The activation energy of K2 was larger than that of K1. The rate-determining process of tritium permeation is considered not to be HT diffusion in the Flibe liquid film, but to be the HT migration from Flibe surface to metal surface, where oxides formed by the impurity in Flibe may accumulate as a tritium permeation barrier.