Addressing Challenges in the Application of the Design Safety Requirements for Nuclear Power Plants to Small and Medium Sized Reactors in Pre-Licensing Vendor Design Reviews in Canada

Abstract of the technical paper/presentation presented at:
IAEA Technical Meeting on Challenges in the Application of the Design Safety Requirements for Nuclear Power Plants to Small and Medium Sized Reactors
September 4–8, 2017, Vienna

Prepared by:
Yi Zeng
Canadian Nuclear Safety Commission

Abstract:

The Canadian Nuclear Safety Commission (CNSC), Canada’s nuclear regulator, is currently conducting vendor design reviews (VDRs) for a number of small and medium sized or modular reactor (SMR) designs. The primary objective of the pre-licensing vendor design review is to identify whether there are fundamental barriers to the licensing of the reactor design in Canada. All of the SMR reactor designs being reviewed by the CNSC under the VDR process are quite different from traditional CANDU or pressurized water reactor designs, with new and novel safety features. The reactor types include lead-cooled reactors, high-temperature gas-cooled reactors, molten salt reactors and sodium-cooled fast reactors. Because existing Canadian regulatory requirements for reactor design are primarily for water-cooled nuclear power plants, CNSC staff find that when it comes to the VDR process, it is very challenging to apply many of the existing requirements in CNSC regulatory documents REGDOC-2.5.2 and RD-367 to these new and novel designs. This presentation describes some examples of the challenges, particularly in applying Canada’s existing reactor shutdown requirements and emergency core cooling requirements to SMRs.

The CNSC’s regulatory framework, including the pre-licensing vendor design review for SMRs, is described in the presentation. Regardless of the reactor design, fundamental safety functions (control, cool, contain and monitor) must be fulfilled, and the defence-in-depth (DiD) principle must be maintained. This presentation discusses the proposed path forward and the plan to deal with the challenges. The graded approach – a key approach in dealing with the challenges – as well as some issues in applying defence in depth to SMRs, are also discussed.

To obtain a copy of the abstract’s document, please contact us at cnsc.info.ccsn@cnsc-ccsn.gc.ca or call 613-995-5894 or 1-800-668-5284 (in Canada). When contacting us, please provide the title and date of the abstract.