Development of ceramic-coated lithium particles for tritium production tests in high temperature engineering test reactor

Ceramic-coated lithium particles (CCLP) are proposed for the tritium production tests in High Temperature Engineering Test Reactor (HTTR). The CCLP-production method and its tritium-retention as well as -release capability are mainly studied. The CCLP consists of a lithium compound kernel coated with ceramic layers. The kernel is made from lithium compound like LiAlO₂. Ceramic materials like Al₂O₃ are used for the coating layers. The present study has made clear that tritium leakage from CCLP is less than 1% after 400-days-heating at 1,000K, and the tritium can be released completely in a short time by heating over 1,400K. From these characteristics, it is expected that the tritium can be well extracted from the CCLP by heating over 1,400K in the post irradiation test after irradiation under 1,000K in the HTTR. Furthermore, a good chemical stability between the kernel and coatings was confirmed through X-ray diffraction tests after heating of their powders. The mechanical integrity of coating layers for inner gas pressure in the CCLP was evaluated to be good on the basis of material data. (author)