The Canadian Nuclear Safety Commission is completing its initial regulatory assessment of the ANEEL fuel project

The Canadian Nuclear Safety Commission (CNSC) has completed an initial regulatory assessment of U.S.-based Clean Core Thorium Energy’s (CCTE) novel thorium-uranium fuel pellet project – also called Advanced Nuclear Energy for Enriched Life (ANEEL) – for intended use in Candu Nuclear Reactors.

The proposed idea behind the new fuel design is to create an intrinsically safer and more efficient pellet/fuel bundle that produces less waste and provides better fuel burn, while retaining the current geometry and operating characteristics to facilitate retrofitting.

The fuel consists of thorium and high-grade low-enriched uranium (HALEU) and is intended for use in pressurized heavy water reactors (PHWR) and Canadian deuterium-uranium reactors (Candu). Clean Core says the fuel can significantly improve the performance of existing, proven heavy water reactor systems by leveraging thorium’s inherent superior nuclear, thermal and physical properties. It also retains the same external dimensions and configuration design as currently used natural uranium (NU) fuel bundles. “Without any significant reactor modifications, replacing current NU fuel bundles with Clean Core’s ANEEL fuel bundles could reduce lifecycle operating costs and waste, increase safety and accident tolerance, and result in additional proliferation resistance,” the company notes. Clean Core completed initial design studies and in April announced the successful completion of Phase 1 of the Pre-Licensing Vendor Design Review (VDR) process with CNSC.

Under the Canadian Nuclear Safety and Control Act, CNSC entered into a services agreement with CCTE in March 2023 to conduct an initial regulatory assessment of the fuel project. CNSC staff conducted this assessment by modifying the documented VDR approach and selecting an appropriate subset of target areas for assessment.

Preliminary regulatory design assessment is an optional service provided by CNSC upon supplier request. This is a high-level review of the vendor’s proposed technology and corporate structure against Canadian regulatory requirements and guidelines. The intention is to provide early feedback to the supplier on issues related to CNSC regulatory requirements and expectations, which may allow for the early identification and resolution of potential regulatory or technical issues in the design and design process, particularly those that may result in significant changes in design.

The assessment does not involve the issuance of a license under the Nuclear Safety and Control Act and is not part of the licensing process. The conclusions of the evaluation do not bind or otherwise affect decisions taken by the Commission. The CNSC says the licensing process for the proposed project would require a more detailed design and safety review for a specific site-specific license application.

As part of the initial review of the regulatory project, CNSC staff were to ensure:

• an overall assessment of the proposed fuel design and qualification program to confirm that CCTE will be able to demonstrate that its nuclear fuel design and qualification programs can meet CNSC expectations, applicable regulatory documents and applicable Canadian codes and standards;
• regulatory information to the CCTE regarding the regulatory process or licensing requirements for new fuel for use at a nuclear power plant facility.

The initial assessment of the regulatory project was carried out over a period of approximately six months. The CCTE presented documents on nine applicable specific areas. The CCTE also held orientation sessions, responded to requests for additional information, and provided technical clarifications through letters, emails, and meetings.

CNSC staff reached the following conclusions:

• CCTE generally understands and has correctly interpreted the overarching assumptions of the CNSC regulatory requirements with respect to fuel design and qualification.
• If this fuel design is considered for use in a Canadian reactor, additional work will be necessary to address the technical clarifications and findings in this assessment.
• It is anticipated that the issues documented in this report will be resolvable and will need to be addressed in any future licensee application or review.
• It is expected that any design changes will be documented and detailed for any future review and/or licensee application for use of the fuel design.

The CNSC said some of its findings and technical clarifications would require additional follow-up in any future reviews. The management system is not yet well documented to meet regulatory requirements, with particular emphasis on establishing supplier management. Given the novelty of certain design features and security features, future licensee assessments or applications will require information to confirm:

• adequacy of research and development activities to justify the fuel qualification program;
• validation and verification of the ability of software tools to model the reactor and analyze the reactor behavior in all operating modes.

In several cases, given the unique design properties of the ANEEL fuel, CCTE proposes alternative approaches and methodologies to meet the core tenets of the CNSC regulatory requirements. The CCTE has indicated that it intends to adequately justify the use of these alternative approaches and is expected to provide evidence in future submissions that these alternative approaches will provide an equivalent or higher level of safety.

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