Evaluation of integrity of coated fuel particles of practical high temperature gas-cooled reactor system

Aihara, Jun ; Ueta, Shohei   ; Ohashi, Hirofumi ; Tachibana, Yukio 

Evaluation of integrity of coated fuel particles of GTHTR300 has already been carried out. On the other hand, new knowledge on pressure vessel failure, one of the causes of failure of coated fuel particles under irradiation, was obtained by preliminary irradiation experiment of coated fuel particles for HTTR up to official burnup of 7% FIMA. Then in this report, extrapolative evaluation of volume averaged pressure vessel failure probability was carried out based on method which is already published. Considering evaluated pressure vessel failure probability, in addition to corrosion behavior of SiC layer and fuel kernel migration of GTHTR300 coated fuel particles, already analyzed in past paper, volume averaged failure probability of coated fuel particles of GTHTR300 at refueling is small in view of public dose by accident, if initial failure probabilities of coated fuel particles are same as those of HTTR first loading fuel.