[1D08-12] External Event PRA 1

[1D08] Probabilistic Risk Assessment of Sodium-cooled Fast Reactors by CMMC Method Considering the Recognition Probability on External Hazards

*Akari Koike¹, Takaaki Sakai¹, Norihiro Doda², Masaaki Tanaka² (1. Tokai Univ., 2. JAEA)

Keywords:Recognition Probability, Accident Management, Sodium-cooled Fast Reactors, The CMMC method, dynamic PRA

In a sodium-cooled fast reactor, the final heat sink of the decay heat removal system is the atmosphere. Therefore, countermeasures against external hazards from the sky are important in extreme weather and natural disasters. This study focused on the execution possibility of accident management (AM) for extreme snowfall events and evaluated the impact of operator recognition on plant safety. We modelled the operator's recognition of the need for AM as a success probability function of time and performed a dynamic PRA analysis using the CMMC method. The analysis results show that the operator's recognition failure affects the core damage initiation time.