Development of level-1 PSA method for sodium-cooled fast reactor

Kurisaka, Kenichi ; Sakai, Takaaki; Yamano, Hidemasa   ; Nishino, Hiroyuki  ; Fujita, Satoshi*; Minagawa, Keisuke*; Yamaguchi, Akira*; Takata, Takashi*

This study includes a level-1 PSA related to internal events and a seismic event as a representative external event for Japan sodium-cooled fast reactors with passive safety features and a seismic isolation system. For the internal events, it is necessary to evaluate the passive safety features, of which reliability depends on uncertainties of related physical phenomena. In order to consider the reliability of the passive natural circulation, accident sequences leading to core damage result from natural circulation failure were developed, and the annual frequency of the accident sequences was evaluated for the PSA method study. In respects of seismic event, we developed response analysis method considering the coupling effect of horizontal and vertical shaking on the horizontal seismic isolation characteristics, and developed a fragility evaluation model including the effect of seismic non-linearly for the seismic isolation system.