Fuel performance under continuous high-temperature operation of the HTTR

Ueta, Shohei   ; Aihara, Jun ; Sakaba, Nariaki ; Honda, Masaki*; Furihata, Noboru*; Sawa, Kazuhiro

Although the HTTR fuel was the first mass-produced HTGR fuel in Japan, it has been fabricated with the highest quality in the world on the basis of design principle and safety criteria to minimize both as-fabricated failure and on-operating-additional failure of the coated fuel particle. A precise technology for evaluating irradiation performance of the HTTR fuel has been developed by measuring fission gases released from fuel and constructing the fission gas release model. Through the HTTR operations including the continuous high temperature operation with 950 C and 50 days, the measured fractional release of fission gas from fuel resulted less than 1.2 10, and a superior irradiation performance of Japanese HTGR fuel has been demonstrated. The HTTR fuel technologies could make a prospect for realization of the practical HTGR as well as the VHTR as a Generation IV nuclear power plant before the rest of the world.