Permeation of multi-component hydrogen isotopes through austenitic stainless steels

In a D–T fusion reactor tritium exists together with other hydrogen isotopes. However, the permeation of multi-component hydrogen isotopes through austenitic stainless steels has not been discussed so far. In this paper the permeation behavior of hydrogen isotopes through type 304 and 316 austenitic stainless steels was investigated by the co-current double tube method in the temperature range of 623–973 K. The permeabilities of hydrogen observed in this study gave close agreement with the recommended value by Le Claire. Discrepancies in reported values for the permeabilities of deuterium are larger than those of hydrogen and there has been no recommended value of permeability. The permeabilities of deuterium were obtained using the same apparatus and the same technique as hydrogen experiments. The isotope effect ratio in permeation for 316SS was smaller than that for 304SS. The permeation behavior of hydrogen isotopes in the binary-component hydrogen isotopes system was also observed under various conditions and compared with the values from the model calculation. It is concluded in this study that the separation factor in permeation through austenitic stainless steels coincides with the isotope effect ratio in permeation.