Computation of consequences of piping component failures in PRA software

In-service inspections are applied to safety important pipe components in nuclear power plants (NPPs) to ensure their reliability. In risk-informed in-service inspections (RI-ISI), these inspections are planned according to risk importance of piping components. The quantitatively computed risk of a piping component combines the probability of the failure and the consequences of the failure. This report focuses on estimating the consequence of piping component failures. A typical measure for the consequences is conditional core damage probability (CCDP), and it can be calculated from a probabilistic risk assessment (PRA) model of a NPP. However, computation of CCDP values of piping component failures has not been automated in PRA software, such as FinPSA, and requires typically additional processing of the model because all piping component failures are not included in the PRA model explicitly. This report introduces a prototype of a new RI-ISI feature which calculates CCDP values of piping component failures in PRA software FinPSA. The RI-ISI feature enables detailed modelling of the consequences of piping component failures without complicating the PRA model itself. The CCDP values of all piping component failures can be calculated automatically at once in the same RI-ISI table based on the results of the PRA model.