CNSC Regulatory Overview on Maintenance and Risk-Based Maintenance
9th International Conference on CANDU® Maintenance - 2011 December 04-06

Presented at:
9th International Conference on CANDU® Maintenance
2011 December 04-06
Toronto, Canada
Session Title:
Industry Performance Special Session A1

Smain Yalaoui (Canadian Nuclear Safety Commission)


In this presentation, the overall Canadian Nuclear Safety Commission (CNSC) regulatory framework as well as the CNSC expectations regarding the maintenance program requirements will be given. This will include a short highlight of the regulatory standards which refer directly (S-210: “Maintenance Programs for Nuclear Power Plants”) or indirectly to maintenance. Emphasis will be placed on the relationship between the CNSC regulatory standards S-210, S-98 “Reliability Programs for Nuclear Power Plants” and S-294 “Probabilistic Safety Assessment for Nuclear Power Plants”.

The presentation will also address the approaches for maintenance prioritization using the PSA importance measures. Maintenance prioritization could be done on a component or on a system basis.  There will be an additional focus placed on the Minimal Cutset prioritization approach which considers the MCS that contribute most to the Core Damage Frequency (CDF) and then identifies the associated maintainable components.

Finally, we will discuss the quantification of the maintenance effects on unavailability and risk. It will be shown how the identification of a degraded state and the use of the Markov models allow the benefits of maintenance to be explicitly evaluated and the optimal maintenance intervals to be determined. The presentation will conclude with a high level discussion regarding the documentation of the maintenance interval extension requests for the systems important to safety as well as the use of risk metrics to support these requests.

Individual Conference-Paper Copies (Electronic Where Available):

  • For CNS members, the first 5 copies per calendar year are free, and additional copies are $10 each.
  • For non-members, the price is $25 for the first Conference-paper copy in a request, and $10 each for additional copies of papers in the same conference and in the same request.
  • Contact the CNS office to order reprints.