Executive summary: Combined phases 1 and 2 pre-licensing vendor design review – General Electric Hitachi Nuclear Energy

Background

General Electric Hitachi (GEH) Nuclear Energy is designing a 300 MW_e (870 MW_th) boiling water reactor, the BWRX-300. The Canadian Nuclear Safety Commission (CNSC), as Canada’s nuclear regulator, under the authority of the Nuclear Safety and Control Act, entered into an agreement with GEH on December 11, 2019, to conduct a combined phases 1 and 2 pre-licensing vendor design review (VDR) of the BWRX-300 reactor. The VDR process is described in REGDOC-3.5.4, Pre-Licensing Review of a Vendor’s Reactor Design.

The purpose of the combined phases 1 and 2 VDR was to determine whether GEH understands CNSC regulatory requirements and the extent to which the reactor design meets those requirements. A VDR takes place during the design process, while the design is still evolving, in an effort to provide early feedback. This allows for early identification and resolution of potential regulatory or technical issues in the design and design process, particularly those that could result in significant changes to the design.

A VDR does not involve the issuance of a licence under the Nuclear Safety and Control Act and is not part of the licensing process. The conclusions of the VDR do not bind or otherwise influence decisions made by the Commission.

Combined phases 1 and 2 vendor design review results

The BWRX-300 review was based on information provided by GEH in over 200 documents. It also included technical presentations, a design process evaluation, and written responses to CNSC questions across 19 focus areas. CNSC staff concluded from this information that GEH understands and has correctly interpreted the intent of regulatory requirements for the design of nuclear power plants in Canada. CNSC staff did not identify any fundamental barriers to licensing. However, the review did reveal some technical areas that need further development in order for GEH to better demonstrate adherence to CNSC requirements:

• Additional information is needed on the sharing of components across defence lines.
• Further detail is required on severe accident analysis and the corresponding engineered features credited for mitigation.
• More in-depth information supporting radiation protection, human factors, decommissioning, and fire protection is needed in order for the CNSC to determine how these programs will meet CNSC requirements.
• It must be demonstrated that the BWRX-300 design meets the requirement for 2 separate, independent and diverse means of reactor shutdown, or else an alternative approach, with justification, is needed.
• Further information is needed on restricting radionuclide release during fuel handling activities.
• Further information is needed on the protective measures for workers in the event of an out-of-core criticality accident.
• A BWRX-300 safety analysis needs to be conducted in accordance with procedures, detailing the technical steps.

These findings and other technical clarifications are to be considered as CNSC staff feedback to GEH to support future licensing applications (e.g., Ontario Power Generation’s application for a licence to construct). The design and safety analysis of the BWRX-300 evolved throughout the VDR, and design details have continued to mature since the CNSC’s review. Design changes within the scope of the regulatory review must be clearly documented by any applicant and will be re-evaluated by CNSC staff as part of any future licensing review.