Estimation of Equipment Fragility Curve of Nonlinear Nuclear Power Plant Structures

Fragility analysis is priorly conducted for probabilistic seismic risk assessment of nuclear power plants (NPPs). In this research, a sample-based method is used to estimate equipment fragility curves more realistically. A numerical model representing an auxiliary building of NPP is used for probabilistic seismic analysis. The structural nonlinearity comes from the hysteretic behaviour of shear walls, which is a dominant structural component affecting the structural behaviour under earthquakes. Uncertainties from ground motions, structural and equipment properties are considered. To generate simulation cases, an advanced Latin Hypercube sampling approach with sequential sampling capability is adopted. The response distribution are utilized for calculating fragility curves, and the effects of each uncertainty sources on fragility curves are evaluated and compared.