Study on Risk Analysis and Mitigation Measures for Total Loss of Heat Sink Accident in a Nuclear Power Plant

There have been multiple water intake blockages caused by marine growth at nuclear power plants (NPPs) in recent years, which draws attention to the risk of loss of cold source as an important nuclear safety issue for NPPs. The results of a level 1 probabilistic safety assessment (PSA) for internal events of a certain NPP in China confirm that total loss of heat sink is one of the major risk contributors. From the perspective of PSA, this article analyzes and evaluates the risk of total loss of heat sink accident of a Chinese second-generation pressurized water reactor (PWR). Possible weak links during the accident mitigation are identified and corresponding suggestions of improvement are provided in order to lower the risk of total loss of heat sink for this NPP.