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

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 578 K with an activation energy of 21 kJ/mol, while CLF-1 steel has two desorption peaks, whose corresponding activation energy is 31 kJ/mol at 563 K and 94 kJ/mol at 797 K respectively. After 2 h thermal desorption, deuterium removal efficiency for CLAM is more than 90% above 373 K. Yet for CLF-1, deuterium removal efficiency is less than 90% below 573 K. Hydrogen isotope exchange can slightly enhance deuterium release. Overall, Deuterium retention in both materials can be removed effectively at relatively low temperature (< 673 K) through thermal desorption due to the high hydrogen diffusivity, especially for CLAM steels.