Study on forest fire related challenges and development of simplified fragility evaluation method for sodium-cooled fast reactor

Okano, Yasushi; Yamano, Hidemasa   

A sodium-cooled fast reactor uses ambient air as an ultimate heat sink under accident conditions. Risk assessment of external hazards such as a forest fire that affect air cooling system is therefore important for safety. This paper describes analyses of forest fire related phenomena and influential factors, and associated potential risks on air cooling system in order to apply to a methodology development of an event progress as a part of a probabilistic risk assessment. A simplified assessment method for fragility of relevant structure and component to maintain decay heat removal function are proposed.