The computation of seismic fragility of equipment components in nuclear power plants

A numerical procedure for the computation of fragility functions for equip-ment components in Nuclear Power Plants (NPP) is addressed in the re-search. The procedure is based on the hypothesis, typical of nuclear struc-tures, of linear behaviour of the building and on the use of the Response Surface (RS) Methodology to model the influence of the random variables on the dynamic response. To account for stochastic loading the latter is computed by means of a simulation procedure. Given the RS, the Monte Carlo method is used to compute the failure probability; a procedure for refining the RS is also proposed and tested in an illustrative example.