In-reactor experiment and the tritium diffusion coefficient in molten lithium–tin alloy

The measurement of the tritium diffusion coefficient in molten Li20Sn80 alloy was carried out using an in-reactor tritium release experiment. The analysis of the measurements is based on a diffusion-controlled steady state model. When the hydrogen partial pressure was higher than 1100 Pa in the purge gas, and the temperature was 873 K or higher, it satisfied the requirements of the model. At 873 K, the tritium diffusion coefficient in the alloy is of order 10−9 m2/s, and the Sievertsʹ constant in Li20Sn80 is below 10−5 Pa−0.5, based on the rough estimation which is supported by the relation of the tritium residence time to the diffusion coefficient and the Sievertsʹ constant in the model.