A Windowed Adjustment Function Based NRC Compliant Ground Motions for Fragility Analysis of Base-Isolated Nuclear Power Plant

摘要

This research presents the influence and sensitivity of United States Nuclear Regulatory Commission (NRC) design spectrum matched multiple ground motions on the development of fragility functions for a base-isolated nuclear power plant (BI-NPP) structure using a new function. A multi-damping adjustment function called windowed tapered cosine adjustment function in time domain is introduced as ground motion modification scheme and its sensitivity is quantified over linearly scaled ground motions (GMs). Spectrally matched and linearly scaled unmatched, both types of GMs are scaled to same PGA level to make sure they have the same GM intensity during structural analysis. Time history analysis of a BI-NPP is carried out to evaluate the efficiency of the windowed adjustment function in the context of seismic response prediction. Fragility curves are developed considering peak ground acceleration (PGA) as ground motion intensity measure using the maximum likelihood method. The lateral displacement of the lead rubber bearing (LRB) has been considered as prime response parameter. It is observed that the windowed adjustment function gives 1.5-2.0 times higher responses found from the ratio of maximum displacement from spectrally matched to linearly scaled GMs.