Evolution of Canadian reliability requirements in a risk-informed environment

An abstract of a technical paper presented at:
American Nuclear Society- PSA 2011
Wilmington, North Carolina, USA
March 13-17, 2011

Prepared by:
Chantal Morin, P. Eng.
Canadian Nuclear Safety Commission (CNSC)
Ottawa, Ontario, Canada

Abstract

This paper will discuss the evolution of design, safety and reliability requirements in Canada over the last forty years. Specifically, we will discuss the recent advancement of reliability requirements in light of the progress in probabilistic safety analysis. The role of Safety Goals within the current regulatory framework will be discussed.

The development of the Canadian nuclear power safety philosophy is traced from its early roots in the 1960s to the current development of more modern requirements in the risk and reliability area. The paper will link the traditional single and dual failure criteria for safety analysis which led to the reliability requirements for special safety systems with the modern advances in probabilistic safety assessment which are leading the current reliability requirements.

Within the last five years, the Canadian Nuclear Safety Commission, the nuclear regulator, has developed a new reliability program regulatory guide whereby the program would not only encompass the four traditional special safety systems, but a more comprehensive list of systems that are deemed important due to their contribution to the risk as determined by the probabilistic safety analysis. Details of the implementation of this new regulatory guide will be discussed such as the conservative versus realistic modeling, human error and mission time inclusion in the models, etc. The paper will also discuss some relevant questions such as; why monitor reliability at the system level while we have a plant model?

To obtain a copy of the abstract's document, contact the CNSC. When contacting the CNSC, please provide the title and date of the abstract.