The Behaviors of Tritium and Helium-3 in China Developed Hydrogen Resistant Stainless Steels

To efficiently confine the gaseous deuterium and tritium, which are the important fuels in the development of fusion energies, China has developed a series of hydrogen resistant stainless steels, named as the HR series of stainless steels. The mechanisms of the interactions between tritium with the decayed helium-3 and these stainless steels were investigated by theoretical calculations, experimental observations or tests through gaseous tritium loading into the stainless steels and years of storage. Results showed that the China made HR stainless steels had good performance to resist hydrogen damage or hydrogen embrittlement. They are the ideal structure materials for tritium systems used in a fusion reactor like ITER. Nevertheless, tritium permeation at high temperatures are still high. Tritium permeation barriers with the aluminides on the surface of the components were successfully developed, which could greatly reduce tritium permeation flux down to 2~3 orders of magnitudes.