Initiating Event Analysis for Site Risk Assessment

Abstract

The purpose of the site risk assessment is to estimate the risk at the site. Not only the initiating events considered in single-unit probabilistic risk assessment, but also common cause initiator that can simultaneously affect the multiple units at the site should be considered in the site risk assessment to achieve its purpose. Previous single-unit PRA considered use blended event records with baseline period on the basis of reactor operation. To consider common cause initiator, the number of accident occurrence needs to be distinguished between single unit initiator and common cause initiator. And proper baseline periods should be defined for specified categories. Frequencies calculated with distinguished event records would consider the dependency exists in initiating events when it is applied to PRA model. In this study, the data of initiating event of Korea would be classified into single unit initiator and common cause initiator to conduct the site risk assessment. The baseline periods would be defined and the initiating event frequencies would be evaluated.