Integrated Molten Salt Reactor Passes Pre-Licensing Milestone

Nuclear Power Industry

WNN reports that the vendor design review provides an opportunity for CNSC staff to assess a design prior to any licensing activities, enabling the vendor to identify potential issues that would require resolution. Phase 1 of the review determines whether the vendor is demonstrating intent to be compliant with CNSC requirements in its design processes and outcomes.

The CNSC announced yesterday that, based on the documentation submitted by Terrestrial Energy, the company had demonstrated an understanding of the regulator's requirements applicable to the design and safety analysis of the 400 MWt IMSR, known as IMSR400. The company has also demonstrated its intent to comply with CNSC regulatory requirements and expectations for NPPs, and is integrating Fukushima lessons learned into IMSR design provisions, the regulator said. Terrestrial Energy will need to undertake additional work to address some of the review's findings, including the need to establish robust quality-assured processes for design and safety analysis activities, the CNSC said.

Issues that will require follow-up work include a need for additional evidence to show Terrestrial Energy has in place a "documented systematic process" to support its design activities. While the CNSC acknowledges the company is working towards establishing quality-assured processes for design and safety analysis activities, many overarching design process documents, such as safety design guides and safety specification documents, are still under development, it said. It expects Terrestrial Energy, in the second phase of the review, to demonstrate it has established sufficient systematic processes in its management system to support its ongoing development activities.

Several features are currently at the conceptual level of design and will require additional technical information, based on research and development and design activities, the CNSC said, while some design features will need further consideration because of the novel design of the IMSR400.

Further work will be needed to predict core behaviour in the presence of damaged core components - although the CNSC acknowledges that the definition of core damage as set out in current regulations, which were drawn up based on operating experience from water-cooled reactors, may not be applicable to the IMSR design. Terrestrial Energy will also be required to complete further safety analysis work relating to core damage, and to provide further information on how it will validate predictions of performance as the reactor ages.

In the second phase of the review, Terrestrial Energy will also be required to demonstrate that human factors in design have been appropriately addressed in its operability and maintainability programs, which are currently under development.