Probabilistic Framework for Seismic Fragility Analysis of Nuclear Power Plants under Earthquake Hazards

The seismic performance of nuclear power plants is critical for the safe operation of nuclear infrastructure. The soil exhibits significant spatial variability, which has an important impact on evaluating the seismic performance of nuclear power plants under earthquake hazard conditions. It is critical to incorporate both seismic and geotechnical uncertainties into probabilistic analyses of nuclear power plants (NPPs). The paper aims to present a probabilistic framework for seismic fragility analysis for nuclear power plants equipped with periodic foundations, considering the combined uncertainties of ground motions and soil properties using Monte Carlo simulations. The seismic fragility curve is defined based on the variability of the performance of the NPPs under different seismic hazard levels in a probabilistic manner. The seismic isolation performance of a layered periodic foundation composed of rubber and concrete materials is investigated through seismic fragility analysis. The results demonstrate that periodic foundations can enhance the seismic resilience of NPPs under the uncertain seismic excitations and complex geotechnical conditions.