Phase 1 Pre-Licensing Vendor Design Review Executive Summary: ARC Nuclear Canada Inc.
Advanced Reactor Concepts (ARC) Nuclear Canada Inc. (ARC Canada Inc.) is designing a 286 megawatt thermal sodium-cooled fast reactor, ARC-100, with a net nominal electrical output of approximately 100 megawatts. 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 ARC Nuclear Canada Inc. to conduct a Phase 1 pre-licensing vendor design review (VDR) of the ARC-100 sodium-cooled fast reactor design. The VDR process is described in regulatory document REGDOC-3.5.4, Pre-Licensing Review of a Vendor’s Reactor Design.
The VDR review is an optional service the CNSC provides when a vendor requests it. It is a high-level review of the proposed reactor technology’s conceptual design information against Canadian regulatory requirements and guidance. The service 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 such a review do not bind or otherwise influence decisions made by the Commission. The CNSC’s licensing processes will require a more detailed review of the design and safety case for a specific licence application at a specific site.
A Phase 1 VDR determines if, at a general level, the vendor’s reactor design and design processes are demonstrating implementation of CNSC regulatory requirements. It is intended to provide early feedback to the vendor, as it addresses Canadian regulatory requirements and other expectations in the vendor’s design. It can allow for early identification and resolution of potential regulatory or technical issues in the design process, particularly those that could result in significant changes to the design or safety analysis.
This Phase 1 report outlines the review process followed, the assessment findings and the conclusions of that review.
Application of REGDOC-2.5.2 to a sodium-cooled fast reactor technology
Regulatory document, REGDOC-2.5.2, Design of Reactor Facilities: Nuclear Power Plants, was written to be technology neutral to the extent practicable. However, the document contains requirements and guidance that incorporate extensive operating experience from the use of water-cooled reactors. It is recognized that vendors of specific technologies may present alternative technological approaches and methodologies; however, alternative approaches remain subject to the same safety objectives, high-level safety concepts and safety management principles articulated in CNSC design and safety analysis documents such as REGDOC-2.5.2. Technical expertise, professional judgment and adequately documented processes are used to ensure that the application of, or departure from, regulatory requirements is objective and consistent so that the required level of safety is achieved.
Phase 1 vendor design review results
The ARC Phase 1 vendor design review (VDR) was carried out over a 24-month period at the request of the vendor. Four packages of 19 technical review focus areas were included, along with familiarization sessions, requests for additional information, and technical discussions through letters, emails, meetings and teleconferences. Based on the documentation submitted, CNSC staff concluded the following:
- ARC understands and has interpreted correctly the high-level intent of the CNSC’s regulatory requirements for the design of nuclear power plants in Canada pertaining to 19 focus areas under consideration for the scope of the Phase 1 VDR.
- In some cases, due to the unique characteristics of the design, ARC is proposing alternative approaches and methodologies to address the underlying intent of CNSC regulatory requirements, in accordance with section 11 of REGDOC-2.5.2. ARC has demonstrated that it intends to adequately justify the use of these approaches and understands that the alternative approaches will be expected to result in an equivalent or superior level of safety.
- Additional work is required by ARC to address the findings raised as part of this review, including the need to implement planned changes to its management system.
The following points are a summary of clarifications or findings that will require additional follow-up in a future review:
- ARC is implementing a number of improvements to its management system. As a result, additional information will be needed in Phase 2 to confirm that ARC Canada’s updated management system processes to control the design, safety analysis and research and development (R&D) activities meet the intent of requirements and expectations from applicable regulatory documents and standards. If a decision is made to proceed with a Phase 2 review, ARC is expected to demonstrate that it has established sufficient systematic processes in its management system to support its ongoing design development activities.
- Additional information is required to demonstrate that the proposed R&D program is commensurate with the challenges posed in the design and analysis of the reactor. This includes a demonstration that systematic and risk-informed R&D program processes are in place, integrated with the management system and design and safety analysis processes.
- Because of the novelty of some of the ARC-100 design and safety features, additional information will be required to confirm:
- adequacy of the R&D activities to substantiate ARC-100 safety claims and the fuel qualification program, including the role of a first-of-a-kind reactor
- applicability of the operating experience data from previous sodium fast reactors to the ARC-100 design and safety analyses
- consistency between the safety functions and the safety classification for the structures, systems and components, and the relationship to ARC’s demonstration of proven engineering practices for specific technological proposals
- adequacy of shutdown means, shutdown margins and the guaranteed shutdown state, which includes demonstration of independence, separation and diversity between control and protection system for all aspects, including design of sensors, logic and actuation
- adequacy of containment function and isolation for all potential initiating events
- verification and validation of computer codes used in the safety analysis
- functionality, adequacy and reliability of inherent and passive safety systems and components claimed in the safety case for the reactor
Notwithstanding the above, these issues are foreseen to be resolvable and will be followed up on in future phases of VDRs.
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