Probabilistic Safety Analysis for Loss of Offsite Power Accident in Dual-units Nuclear Power Plant

In order to explore the risk assessment method of the multi-unit nuclear power plant site, this paper selects the dual-unit plant nuclear site to analyze lose off-site power accident. By combining and improving the single-unit ET/FT model, to establish the dual-unit ET/FT model. From the analysis of the accident sequence, it can be concluded that the common cause failure of equipment is the main challenge faced by the dual-units. Especially the RPC sub-channel in the reactor protection system and the failure of emergency diesel engine circuit breaker. As can be seen from the high proportion of core CD occurring simultaneously in both uints, it has a great significance to study the risk of mult-units sites