Evaluation items to attain safety requirements in fuel and core designs for commercial HTGRs

Nakagawa, Shigeaki  ; Sato, Hiroyuki  ; Fukaya, Yuji   ; Tokuhara, Kazumi; Ohashi, Hirofumi 

As for the design of commercial HTGRs, the fuel design, core design, reactor coolant system design, secondary helium system design, decay heat removal system design and confinement system design are very important and quite different from those of LWRs. To contribute the establishment of the safety standards for commercial HTGRs, the evaluation items to attain safety requirements in fuel and core designs were studied. In this study, the excellence features of HTGRs based on passive safety or inherent safety were fully reflected. Additionally, concerning the core design, the stability to spatial power oscillation in reactor core of HTGR was studied. The evaluation items as the result of the study are applicable to the safety design of commercial HTGRs in the future.