US-based Holtec International said that its SMR LLC subsidiary had completed Phase 1 of the Canadian Nuclear Safety Commission (CNSC) Pre-Licensing Review of a Vendor’s Reactor Design for its small modular reactor design, the SMR-160.
A Vendor Design Review (VDR) is an assessment service CNSC provides to nuclear power plant designers.
The benefits of this direct engagement are early feedback on the SMR-160 design as it addresses CNSC regulatory requirements and early identification and resolution of potential regulatory or technical issues on the design process, Holtec said.
“This milestone reinforces our expectation that the SMR-160 will meet Canada’s regulatory requirements while also providing valuable feedback that will allow us to further improve the design throughout the ongoing regulatory process,” said Holtec International President and CEO Dr Kris Singh.
SMR LLC started Phase 1 of the VDR in mid-2018, addressing the associated 19 focus areas and submitting hundreds of documents over the course of 18 months to support the review. “As expected, the CNSC identified some areas that require follow-up in Phase 2 of the VDR as the review moves further into the details of the design.” Holtec noted., SMR LLC plans to pursue a Phase 2 VDR “in the near future”.
The SMR-160 is a light-water based pressurised small modular reactor, with a capacity of 160MWe (525MWt) and relies on gravity to operate the reactor and the completely passive safety systems. The SMR-160 is a universal reactor because it can be operated in any terrain, said Holtec.
Much of the engineered equipment needed for SMR-160 will be manufactured at Holtec’s Advanced Manufacturing Division in New Jersey, although satellite manufacturing plants in other SMR-160 host countries are also planned.
CNSC said SMR LLC had submitted 130 documents and drawings broken up in five work packages to cover the 19 technical review focus areas, in addition to providing familiarisation sessions, responses to requests for additional information, and technical clarifications through letters, emails, meetings, and teleconferences. Based on the documentation submitted, CNSC staff concluded that, “Overall, SMR LLC mostly understands and has correctly interpreted the high-level intent of the CNSC’s regulatory requirements for the design of nuclear power plants in Canada pertaining to the scope of the Phase 1 VDR.”
Clarifications or findings that will require additional follow-up in a future review include:
- CNSC staff expect an explanation as to how design codes and standards are selected and how they either comply with or meet the intent of Canadian requirements.
- CNSC staff expect to see a plan that describes how fire protection assessments are being incorporated into the design as it develops.
- SMR LLC acknowledged a need to develop a probabilistic safety analysis (PSA) but indicated that several PSA and hazard assessment methodologies would not be prepared until later. These methodologiesare needed both to evaluate the vendor’s understanding of CNSC requirements and to explain how the PSA results will be developed. These results are necessary to demonstrate that the design meets the established safety goals.
Given the novelty of some of the SMR-160 design and safety features, additional information will be required to confirm:
- adequacy of the R&D activities to substantiate the fuel qualification programme, including the role of a first-of-a-kind reactor;
- application of the single-failure criterion to the control systems under all operating conditions;
- adequacy of the shutdown means under all conditions, including scenarios where the main control room is lost;
- applicability of selected design standards for containment structures; application of research results in the development of the reactor design;
- completeness of the R&D programme to inform long-term reactor operation, including ageing and maintenance of structures, systems and components.
CNSC said these issues “are foreseen to be resolvable and will be followed up on in future phases of the VDR.”