Reflecting Digital I&C Design Lessons Learned in Technology-Neutral Design Requirements

Abstract of the technical paper presented at:
International Conference on Topical Issues in Nuclear Installation Safety: Safety Demonstration of Advanced Water-Cooled NPPs
June 6–9, 2017

Prepared by: Z.C Zeng, G. Renganathan, M. de Vos, J.Y. Fiset, J. Churchill, G. Chun
Canadian Nuclear Safety Commission


This paper describes a regulatory framework project by the Canadian Nuclear Safety Commission (CNSC) to reflect digital instrumentation and control (I&C) design lessons learned in technology-neutral design requirements. This additional information is intended to increase clarity during application of design requirements for the development, construction and commissioning of I&C systems for small modular reactors (SMRs), advanced reactor concepts and new nuclear power plant (NPP) technologies. The new information will appear as an I&C appendix in a revised version of CNSC regulatory document REGDOC-2.5.2, Design of Reactor Facilities: Nuclear Power Plants, which was published in 2014. In addition, the next iteration of CNSC regulatory document RD-367, Design of Small Reactor Facilities will include supplemental I&C information.

The project is seeking to supplement existing I&C requirements and guidance contained in REGDOC-2.5.2, which can be applied to the design of all of the above types of power reactors. The document is also aligned with accepted national and international standards and practices.

Stakeholder interactions with CNSC staff indicated a need for further information on how the CNSC would proceed with licensing of projects that would involve SMRs, as well as other power reactor technologies. As a result, specific to I&C systems, this project will:

  • incorporate I&C design lessons learned from new-build NPP projects from around the world
  • incorporate operational experience from digital I&C systems used in Canadian NPPs
  • incorporate common positions produced by various digital I&C and safety-critical software working groups such as theNuclear Energy Agency Multinational Design Evaluation Programme (MDEP) and Task Force on Safety Critical Software (TF‑SCS)
  • address questions from technology developers of new reactors during CNSC technical review under the CNSC’s vendor design review process
  • articulate that the complexity and proven-ness of I&C systems, and associated uncertainties, has a significant impact on the facility safety case

Following additional analysis and stakeholder consultations, three areas were identified as requiring additional clarity:

  • understanding the implications of and controlling complexity in I&C architectural design
  • systematic approaches to performing hazard analysis and fault management
  • incorporating human factors into the full lifecycle of I&C design activities

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