C-98--Reliability of Systems Important to Safety in a Nuclear Facility

Abstract

Reliability targets, requiring that the risk from a nuclear power plant be less than that from other hazardous industrial activities, were set from the beginning of the nuclear era in Canada, [1]. Since demonstrating that a plant meets these requirements with the then available techniques was not possible, the AECB progressively introduced unavailability requirements for the Special Safety Systems (Shutdown, Emergency Core Cooling and Containment). Nevertheless, checking that the plant design was really was still not possible balanced, i.e., that the different system designs and monitoring were commensurate with their contribution to plant safety was not possible. The development of new methods and enhanced computing power has led to the generation of comprehensive reliability models for the Special Safety Systems and to the development of PSAs. This document, C-98, has taken this progress in consideration. As a result, the new AECB policy requires that the licensees identify every system important for safety, determine its failure and success criteria, and that should be a reliability target set, monitored and maintained, commensurate with the contribution of the system to plant safety. Reporting the results is a part of that policy.