The role of Probabilistic Risk Assessment in the Periodic Safety Re-assessment of Koeberg Nuclear Power Plant, South Africa

This paper describes the role of the Probabilistic Risk Assessment (PRA) in the Periodic Safety Re-assessment of Koeberg Nuclear Power Station, within the context of the Licensing requirements of the South African Nuclear Regulatory Authority i.e. the National Nuclear Regulator (NNR). In order to fully understand the role of the PRA in the Periodic Safety Re-assessment of the Koeberg Nuclear Power Station, a brief introduction of the Licensing philosophy and processes adopted by the NNR is given, the PRA being an integral component of these. As part of the Koeberg Safety Reassessment (KSR) Project, the PRA was benchmarked against international standards. The KSR Project was developed in co-operation with Eskom, which is the national electricity utility in South Africa and also the operator of the Koeberg Nuclear Power Plant. The two primary objectives of this multi-disciplinary project are to compare the plant design basis and operating practices with current internationally recognised standards and to evaluate the risk assessment methodology employed at Koeberg against internationally recognised standards to ensure that the plant continues to meet the risk criteria laid down by the NNR. The comparison process identified numerous differences. These differences were screened for safety significance and dispositioned accordingly. This screening process was developed and subsequently implemented during the review process, taking cognisance of the NNR licensing principles, including the use of PRA insights. In conclusion, the role of the PRA was found to be a significant integral component in achieving the primary objectives of the Koeberg Periodic Safety Re-assessment.