Deuterium retention removal in China reduced activation ferritic-martensitic steels through thermal desorption and hydrogen isotope exchange

Abstract

Effective removal of deuterium and tritium trapping in fusion reactor materials is of great importance both to recycle fuel and prevent the performance degradation. Experiments on deuterium removal in China Low Activation Martensitic (CLAM) steel and China Low-activation Ferritic (CLF-1) steel through thermal desorption and hydrogen isotope exchange have been performed. The results indicate that CLAM steel has only one desorption peak at 578K with an activation energy of 21kJ/mol, while CLF-1 steel has two desorption peaks, whose corresponding activation energy is 31kJ/mol at 563K and 94kJ/mol at 797K respectively. After 2h thermal desorption, deuterium removal efficiency for CLAM is more than 90% above 373K. Yet for CLF-1, deuterium removal efficiency is less than 90% below 573K. Hydrogen isotope exchange can slightly enhance deuterium release. Overall, Deuterium retention in both materials can be removed effectively at relatively low temperature (<673K) through thermal desorption due to the high hydrogen diffusivity, especially for CLAM steels.