The NUREG-1150 probabilistic risk assessment for the Peach Bottom Atomic Power Station

Abstract This paper summarizes the findings of the probabilistic risk assessment (PRA) for Unit 2 of the Peach Bottom Power Station performed in support of NUREG-1150. The emphasis is on the “back-end” analyses, that is, the accident progression, source term, and consequence analyses, and the risk results obtained when the results of these analyses are combined with the accident frequency analysis. The results show that the annual risk from internal initiators is much lower than estimated by the Reactor Safety Study (RSS) over a decade ago. The risk from fire initiators is about an order of magnitude higher than the risk from internal initiators, but is still less than the risk from internal initiators estimated by the RSS. The risk from seismic initiators at Peach Bottom is much greater than the risk from internal initiators. The uncertainty band for all types of initiators is considerably greater than that estimated in the RSS.