Small-sized high temperature reactor (MHR-50) for electricity generation; Core design with long refueling interval

Terada, Atsuhiko  ; Shimakawa, Satoshi; Shibata, Taiju ; Shiozawa, Shusaku*; Minatsuki, Isao

High Temperature Gas-cooled Reactor (HTGR) has several features different from conventional light water reactors such as high passive safety characteristics, high thermal efficiency and high economy for small sized reactor with modular concept. On the other hand, one of disadvantages of HTGR with prismatic core is to require rather long-term and expensive refueling, resulting in relatively high maintenance period and cost. To solve the disadvantage, the present study challenges the core design of MHR-50 for long refueling interval by increasing core size, fuel loading and fuel burn-up. The preliminary burn-up calculation suggested that approximately 10 years of long refueling interval was found to be reasonably achieved.