Multi external event probabilistic safety assessment framework

The 2011 Fukushima nuclear accident highlighted the need for thorough safety assessments of nuclear power plants, especially in the context of multi natural hazards that may occur simultaneously or sequentially. With climate change increasing both the frequency and intensity of natural hazards like typhoons, tsunamis, and extreme weather events, external event risk assessment frameworks have become essential. This study identifies natural hazards impacting nuclear power plants and introduces a multi external probabilistic safety assessment (PSA) framework. The proposed framework systematically evaluates nuclear plant risk under extreme and multi hazard using statistical data. The methodology incorporates steps such as hazard screening, correlation analysis, fragility analysis, accident scenario modeling, and risk analysis. Finally, a comprehensive risk assessment is conducted by combining results from the hazard and fragility analyses. A case study on nuclear power plants in Korea demonstrates the application and effectiveness of this multi external event PSA approach, aiming to enhance preparedness and resilience of nuclear facilities against increasingly multi natural hazards.