Risk Analysis of Piping System of NRNF

Abstract

A preliminary risk analysis of piping system of non-reactor nuclear facility (NRNF) has been carried out for radiological hazards. In order to estimate the risk, one needs to estimate the frequency of occurrence of piping failure and consequences due to that failure. The piping system is subjected to both static and dynamic loads. Hence, in estimating the failure frequency of piping system, seismic hazard curves have been utilised besides its fragility curves. In the present case, these hazard curves have been taken from the available literature. In general, fragility curves are developed by using conventional factor of safety approach. However, in the present study, generation of fragility curves based on response surface methodology by using finite element modelling of piping system has been proposed. Based on the limit state functions developed, failure probability of a component has been obtained by using structural reliability method. The piping failure frequency has been estimated by convoluting both seismic hazard curves and the fragilities of the piping system. Finally, consequences have been estimated by using point kernel technique and thereby estimated the risk. It is found that the risk is in acceptable limits.