Influence of Frequency Content of Ground Motions on Seismic Fragility of Equipment of a Nuclear Power Plant

Abstract

The objective of this study is to investigate the influence of frequency content of ground motions on seismic fragility of equipment in an APR1400 type nuclear power plant. A framework of seismic fragility analysis of structures, systems or components is proposed using frequency domain analysis method, and is applied to three-dimensional finite element models of an auxiliary building and a containment building. Fragility functions based on realistic response parameters are developed. Three sets of ground motions are selected according to frequency contents and the probabilities of failure for critical equipment and structures are calculated. Revised PGA-based fragility functions are also developed based on the selected ground motions. The system-level resilience of the target NPP is assessed by the CIRAF framework and the results show that ground motions with high frequency content cause the most damage to the NPP system in terms of the system-level failure probabilities and resilience.