Evaluation of tritium confinement performance of alumina and zirconium for tritium production in a high-temperature gas-cooled reactor for fusion reactors

Katayama, Kazunari*; Ushida, Hiroki*; Matsuura, Hideaki*; Fukada, Satoshi*; Goto, Minoru  ; Nakagawa, Shigeaki  

Tritium production utilizing nuclear reactions by neutron and lithium in a high-temperature gas-cooled reactor is attractive for development of a fusion reactor. From viewpoints of tritium safety and production efficiency, tritium confinement technique is an important issue. It is known that alumina has high resistance for gas permeation. In this study, hydrogen permeation experiments in commercial alumina tubes were conducted and hydrogen permeability, diffusivity and solubility was evaluated. By using obtained data, tritium permeation behavior from an AlO-coated Li-compound particle was simulated. Additionally, by using literature data for hydrogen behavior in zirconium, an effect of Zr incorporation into an AlO coating on tritium permeation was discussed. It was indicated that the majority of produced tritium was released through the AlO coating above 500C. However, it is expected that total tritium leak is suppressed to below 0.67% of total tritium produced at 500C by incorporating Zr fine particles into the inside of AlO coating.