Analysis of initiating events in fire PSA under low power and shutdown conditions

Probabilistic safety assessment (PSA) is one of the main methods for nuclear power plant fire safety assessment. At present, fire PSA at power condition has been widely carried out, but there are still few studies on fire PSA in low power and shutdown conditions (LPSD). The initiating events analysis is the starting point for the development of the fire sequences, and it is also an important step of the fire PSA. Fire PSA needs to identify the initiating events directly or indirectly caused by the failure of equipment and cables in fire, which is the basis for building the response model of fire PSA. Meanwhile, the power plant configuration and operate state under LPSD are also different. Therefore, based on the actual state characteristics of LPSD, this paper studies the fire PSA equipment and cables that may be affected and the initiating events that may occur in the fire compartment when the fire happened in LPSD, laying a dedicated list of fire initiating events as the foundation for the study of fire PSA in LPSD.