Development of risk assessment methodology of decay heat removal function against external hazards for sodium-cooled fast reactors, 1; Project overview and margin assessment methodology against snow

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 a combination of a snowfall rate and duration. Since snow removal can be expected during the snowfall, the developed snow margin assessment methodology is such that the margin was regarded as the snowfall duration up to the decay heat removal failure which was defined as when the snow removal rate was smaller than the snowfall rate.