Measurements of the T diffusion coefficient in molten Li20Sn80 alloy were carried out by using an in-reactor T-release method. The analysis of the measurements was based upon a diffusion-controlled steady-state model. When the H partial pressure was higher than 1100Pa in the purge gas, and the temperature was 873K or higher, it satisfied the requirements of the model. At 873K, the T diffusion coefficient was of the order of 10−9m2/s, and the Sieverts constant was below 10−5/Pa0.5; based upon a rough estimate which was supported by the relationship of the T residence-time to the diffusion coefficient and the Sieverts constant in the model.

In-Reactor Experiment and the Tritium Diffusion Coefficient in Molten Lithium–Tin Alloy. Y.Kang, T.Terai: Journal of Nuclear Materials, 2004, 329-333[2], 1318-21