Methods to derive seismic fragility of NPP components: A summary

Seismic fragility of structure, system or component (SSC) is the probability of its reaching a limit state, for a given seismic demand. It is evaluated in terms of ground motion parameters, which is generally peak ground acceleration. Seismic fragility of a nuclear power plant (NPP) is derived from the fragility of its SSC. Seismic qualification, prerequisite for determination of seismic fragility of the SSC of a NPP, is conducted by either direct method involving analysis and testing; or indirect one involving experience based method. The paper surveys and summarizes the methods available to derive the seismic fragility of SSC(s) of an NPP, which are qualified by direct as well as indirect methods.

Research highlights▶ Literature survey summarizing approaches to evaluate fragility parameters of NPP components. ▶ Generic approach to formulate the fragility parameters in terms of three factors. ▶ Approaches to derive median value and uncertainties of these factors are reviewed and summarized. ▶ Determination of overall fragility of a SSC from fragility of different failure mode.