Towards Risk-informed in-service Inspection for CANDU Nuclear Power Plants

Abstract

Risk-informed in-service inspection (RI-ISI) program has been applied in several countries to enhance the traditional periodic inspection program (PIP). While the Canadian Nuclear Safety Commission is becoming increasingly interested in risk-informed decision making and at the same time small-scale pilot studies on RI-ISI have been initiated by Canadian utilities, a RI-ISI methodology appropriate for the CANDU industry that can be accepted by the stakeholders has yet to be developed. The paper discusses the major steps of RI-ISI, compares the RI-ISI methodologies currently used in international nuclear power industry and reviews the Canada’s current periodic inspection standard CSA N285.4-05 from a RI-ISI perspective. The aim of the paper is to identify implications of transitioning from the traditional PIP as defined by CSA N285.4 to RI-ISI and to suggest a path forward for applications of RI-ISI at CANDU stations.