A comparative study of station blackout scenario dynamics initiated by internal and seismic event in boiling water reactor

This paper studies one of the most challenging accident scenarios for nuclear power plants, the loss of power sources, referred to as a station blackout initiated by each different initiator. Recently, the station blackout accidents were highlighted by the Fukushima disaster in Japan on 2011. At Fukushima, tsunami hit the plant site and approximately one hour after the earthquake led to the loss of power, eventually leading to a significant core damage in multiple units. Unfortunately, the accident management against an overwhelming earthquake followed by a tsunami was not properly performed to avoid a fatal damage to plant site and environment. Current accident management in the station blackout scenario has no distinct differences by each different initiator, internal or external event. To find the differences in accident progression and a relevant management for both internal and seismic station blackout sequences, comparable sets are identified and analyzed from the Probabilistic Safety Analysis, accident management plan of the reference boiling water reactor. Findings from this study would contribute to improve a current understanding of the station blackout scenario dynamics and a proper operator responses of the boiling water reactor in each internal and seismic initiated sequence.