Development of PRA and margin assessment methodology of decay heat removal function against external hazards

Yamano, Hidemasa   ; Nishino, Hiroyuki  ; Kurisaka, Kenichi ; Okano, Yasushi; Sakai, Takaaki; Yamamoto, Takahiro*; Ishizuka, Yoshihiro*; Geshi, Nobuo*; Furukawa, Ryuta*; Nanayama, Futoshi*; Takata, Takashi*; Azuma, Emiko*

This paper describes mainly snow margin assessment methodology development in addition to the project overview. For the snow margin assessment, the index is the combination of a snowfall rate and duration. Since snow removal can be expected for the snowfall, this study developed the snow margin assessment methodology that the margin was regarded as the snowfall duration to the decay heat removal failure which was defined as when the snow removal rate was smaller than the snowfall rate.