Research and development on HTGR fuel in the HTTR project

In the high temperature gas-cooled reactors (HTGRs), refractory coated fuel particles are employed as fuel to permit high outlet coolant temperature. The high temperature engineering test reactor (HTTR) employs tri-isotropic (TRISO)-coated fuel particles in the prismatic fuel assembly. Research and development on the HTTR fuel has been carried out spread over about 30 years, in fuel fabrication technologies, fuel performance, and so on. Furthermore, for upgrading of HTGR technologies, an extended burnup TRISO-coated fuel particle and an advanced type of coated fuel particle, ZrC-coated fuel particle in order to keep the integrity at higher operating temperatures has been developed. The present paper provides experiences and current status of research and development works for the HTGR fuel in the HTTR Project.