A Case for Shutdown Cooling System Exemption From the Periodic Inspection Program

Abstract

The Periodic Inspection Program (PIP) is conducted at CANDU stations to comply with the mandatory requirements in Canadian Standards Association (CSA) Standards N285.4, N285.5 and N287.7. A heavily-inspected system in this program is the Shutdown Cooling (SDC) System, which accounts for about 15% of the overall inspections. This paper presents a case to remove most of the SDC System from the PIP since the worst-case accident of the SDC System results in public radiological doses that are low enough to allow exemption under N285.4. This provides an opportunity for CANDU owners to inspect the SDC System on an owner-prescribed basis at their own schedule. This will reduce costs and personnel doses and allow the allocation of resources and funding to more safety-important inspections.