SAPHIRE ‘Recover Cut Sets’ editor: a technique for automating the manipulation of PRA cut sets

The accident sequence cut sets generated for a probabilistic risk analysis generally require some manipulation to account for special modelling concerns. This paper presents a method of efficiently manipulating cut sets, specifically for the modelling concerns of (a) post-accident operator recovery actions, (b) common cause failure modelling, and (c) removal of mutually exclusive events. The method presented consists of logic rules that define a cut set search criteria and changes to be applied to the cut sets meeting the search criteria. While this method of cut set manipulation is demonstrated using the ‘Recover Cut Sets’ editor in the SAPHIRE risk assessment computer code, it is proposed that this methodology could become a standard method for cut set manipulation.