The SMR RF produces consensus-based reports on technical and regulatory SMR-related issues. The reports are developed by the SMR RF Working Groups (WGs) and approved by the SMR RF Steering Committee.
The SMR RF reports are based on information, insights, and experience gained from the regulatory activities of the SMR RF Members and are intended to provide useful information to regulatory bodies and industry in the development, deployment, and oversight of SMRs. The IAEA Safety Standards and other publications serve as reference for the SMR RF discussions and its common positions, but the key findings are produced by consensus by the Forum's experts and based on their own experiences and may, therefore, deviate from the IAEA publications. In such cases, they usually present suggestions for revision or drafting of new IAEA publications related to SMRs.
The content produced by the SMR RF is protected by copyright. The Forum strives to make information concerning its activities available in the public domain, and its reports are publicly available. However, where external parties seek to use this information, in part or in its entirety, for their own purposes, the Forum requires the parties to seek authorization from the Scientific Secretary at:
SMR RF Contact Point
From March 2015 to May 2017, the SMR RF was conducted as a pilot project, with the objective of addressing different regulatory issues for both light-water and non-light-water SMR designs.
Three Working Groups (WGs) were established and produced the following reports:
SMR RF Pilot Project Report:
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This report summarizes the key findings, including common positions in relation to application of the principles of the graded approach, defence-in-depth and emergency planning zones to SMRs. The appendices to this report contain SMR project status and issues in Forum Member States (Appendix I), reports from each of the Forum WGs (Appendices II – IV), and the survey sent out by the Graded Approach and Defence-in-Depth WGs (Appendix V).
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here to download the complete report and
here for a version without appendices.
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Appendix II: Report from Working Group on Graded Approach:
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This report focuses on applying the graded approach to regulating SMRs, considering the novel SMR technologies and the understanding of Member States' policies.
Through the analysis of how the graded approach is applied in different Member States (Canada, Finland, France, Russia, USA), common elements and differences in regulatory frameworks, as well as challenges and specific practices in applying the graded approach to SMRs are identified.
In addition to the key findings and recommendations for enhancing the application of graded approach to SMRs, this report also presents suggestions for future work, including developing a technical document by the IAEA on this topic.
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here to download the report.
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Appendix III: Report from Working Group on Defence-in-Depth:
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The report addresses the application of the Defence-in-Depth (DiD) concept to SMRs, highlighting its importance in ensuring nuclear safety and identifying key regulatory challenges and recommendations for SMRs.
The report discusses unique SMR features, such as smaller size, novel technologies, modular design, and varied applications, and how these impact the application of DiD principles. Key safety issues related to siting, design, and post-design activities, as well as internal and external hazards, redundancy, diversification, and probabilistic safety assessments (PSAs), are thoroughly analysed.
The report also underscores the importance of effective emergency arrangements and the independence of DiD levels to ensure robust safety measures for SMRs.
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here to download the report.
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Appendix IV: Report from Working Group on Emergency Planning Zone:
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The report addresses the regulatory challenges related to the size of Emergency Planning Zones (EPZ) for SMRs. It emphasizes the need for scalable EPZ sizes based on specific design characteristics and site-specific considerations. Key factors influencing EPZ size include plant design, postulated initiating events, safety analyses, and offsite dose consequences.
The report shares regulatory experiences, captures good practices, and discusses the effectiveness of the IAEA safety requirements and methodology in establishing EPZs. The report also highlights the importance of considering local infrastructure, public and political policies, and the need for community emergency preparedness, especially when EPZs are near densely populated areas.
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here to download the report.
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Upon successful completion of the 'Pilot Phase', in November 2017, the SMR RF continued to Phase 2 and established the following new Working Groups (WGs):
- Licensing Issues (LI) WG
- Design and Safety Analysis (DSA) WG
- Manufacturing, Construction, Commissioning and Operation (MCCO) WG
SMR RF Phase 2 Summary Report:
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This report summarizes the key Phase 2 findings of the LI, DSA and MCCO WGs, including common positions in relation to: key regulatory interventions during a SMR lifecycle; potential issues related to the licensing process for a 'first of a kind' vs 'nth of a kind' design; licensing of new build projects with multiple module/unit facilities; multi-unit/multi-module aspects specific to SMRs; considerations in the use of passive and inherent safety features in SMR designs; aspects of beyond design basis analysis relevant to SMRs; manufacturability, supply chain management and commissioning of SMRs; collection and use of experience in the lifecycle of SMR facilities; conduct of maintenance in SMRs; conduct of co-activities and combined activities on a multiple unit SMR facility site.
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here to download the summary report.
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SMR RF Phase 2 Report from Working Group on Licensing Issues:
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This report produced by LI WG presents the key findings on the following topics:
- Regulatory Interventions: emphasizes the importance of strategic regulatory points during the SMR lifecycle, ensuring efficient validation of safety and progression of regulatory activities.
- First of a Kind (FOAK) vs. Nth of a Kind (NOAK) Designs: discusses the differences in licensing FOAK and NOAK SMR projects, highlighting the need for additional demonstration requirements for FOAK designs.
- Multi-Module Licensing: addresses the challenges and considerations in licensing multi-module/unit SMR facilities, including shared safety systems, personnel, and control rooms.
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here to download the report.
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SMR RF Phase 2 Report from Working Group on Design and Safety Analysis:
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This report produced by DSA WG addresses the following topics:
- Multi-Unit/Module Aspects: explores the safety and operational benefits and challenges of multi-unit/module SMR designs, emphasizing the importance of defence-in-depth (DiD) and hazard considerations.
- Passive and Inherent Safety Features: evaluates the use of passive and inherent safety features in SMR designs, addressing uncertainties in performance claims and the need for integrated testing.
- Beyond Design Basis Analysis: discusses the characterization of severe accidents for novel SMR concepts and the role of DiD in preventing and mitigating severe accidents.
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here to download the report.
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SMR RF Phase 2 Report from Working Group on Manufacturing, Construction, Commissioning and Operation:
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This report produced by DSA WG addresses the following topics:
- Modularity and Manufacturability: highlights the implications of modularity in SMR design and construction, stressing the importance of early involvement of suppliers and the need for tailored standards.
- Supply Chain Management: emphasizes the need for robust supply chain management to mitigate risks from a diverse and global supply chain.
- Commissioning and Operations: discusses the importance of a comprehensive commissioning program and the need for systematic experience measures throughout the SMR lifecycle.
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here to download the report.
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In November 2020, the SMR RF Steering Committee approved the topics for Phase 3 (2021-2023), to be addressed by the same LI, DSA and MCCO WGs as in Phase 2. However, since 2022, the LI WG has been leading the NHSI Regulatory track WG3 tasked with developing processes for leveraging other regulatory bodies' reviews and for enabling regulators to work together during ongoing regulatory reviews.
The final reports for Phase 3 were completed in December 2023 and published in early 2024. The five reports developed during Phase 3 can be found below:
SMR Regulators' Forum Phase 3 Summary Report:
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This report summarizes the key Phase 3 findings of the DSA and MCCO WGs, including common positions in relation to containment systems, safety, security, safeguards (3S) interface management, regulatory considerations for long-lead items and authorized activities of Licensees.
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here to download the summary report.
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Containment Systems:
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The containment building/structure is the principal barrier to radionuclide release credited during accidents for the traditional light water-cooled reactor (LWR) designs.
However, based on claims related to inherent and passive safety features, the reliance on the building/structure and its associated systems to provide the containment function is expected to be reduced in some advanced non-LWRs design, which may propose different provisions to limit radionuclide releases to the environment.
For these designs without a pressure retaining containment structure, the DSA WG endorses the term 'functional containment' and provides common regulatory positions on aspects related to SMR containment systems.
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here to download the report.
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Safety, Security and Safeguards from a Regulatory Perspective: An Integrated Approach:
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Considerations of safety, security, and safeguards (3S) are essential in the design, construction, commissioning, operation and decommissioning stages of nuclear reactors, including SMRs.
To take advantage of synergies and resolve potential conflicts, the 3S interface management should be approached in a coordinated, risk-informed and balanced manner during the design stage.
This report:
- identifies key aspects of SMRs relevant to the adoption of the 3S-by-design;
- outlines a range of 3S interfaces;
- provides possible methodologies for integration of 3S;
- recommends good regulatory practices.
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here to download the report.
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Regulatory Considerations in Pre-Licensing Engagement for Long Lead Item Requests:
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For SMRs, the manufacture of safety significant long-lead items (LLI) may occur prior to the establishment of a Licensee or with a smaller Licensee organization than typical.
On the other hand, organizations seek all regulatory assurance to proceed with the manufacture of LLI to speed up delivery of multiple unit projects.
This report addresses these issues and:
- introduces LLI for SMRs and associated regulatory challenges;
- considers the regulation of long-lead procurement if Licensee is still not know;
- identifies regulatory considerations of the "off-the-shelf" manufacturing business model.
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here to download the report.
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Conduct of Authorised Activities Impact on Stakeholders' Organisational Capabilities (Designers, Vendors, Manufacturers, Supply Chains, Operators):
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The introduction of SMRs might impact the conduct of authorized activities by Licensees, in particular, their capability to ensure that their work and that performed by their supply chain demonstrably meets the requisite standards, recognizing that some work (e.g. SMR design or module manufacture) may have been completed long before making an application to the regulator.
It is also important to consider that, with SMRs, Licensee will likely be a smaller organization, more reliant on supply chain organizations and contractors, or even a new entity altogether.
This report explains differences in the SMR business model and its effect on Licensee's ability to conduct authorized activities, considering changes in size and capability of the Licensee.
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here to download the report.
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Phase 4 of the SMR Regulators' Forum commenced in 2024 and will run until the end of 2026. Under this programme, the Forum has published three new reports developed as part of its Phase 4 work:
Mechanistic Source Term:
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This report has been produced by the Design and Safety Analysis (DSA) Working Group (WG) of the SMR RF during its working Phase 4 (2024 to 2026). It explores the application of mechanistic source term (MST) methodologies in the safety analysis of SMRs, particularly non-light water reactor (non-LWR) designs. Unlike traditional conservative approaches, MST uses realistic, scenario-specific modelling to assess the release and transport of radionuclides during nuclear accidents.
This MST approach enables more accurate assessments tailored to novel reactor designs, some of which do not rely on traditional containment structures or assume core melt scenarios. The report presents considerations, challenges and regulatory perspectives related to the use of mechanistic source term approaches for small modular reactors.
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here to download the report.
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Manufacturing without an Owner/Licensee:
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This report has been produced by the Manufacturing, Construction, Commissioning and Operation Working Group (MCCO WG) of the SMR RF during its Phase 4 of work (2024 to 2026). It explores the innovative concept of off-the-shelf manufacturing for SMR components and modules in scenarios without a designated owner or licensee.
This approach is recognized for its potential to streamline deployment and reduce costs, and this report aims to unravel the complex challenges and opportunities that it presents.
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here to download the report.
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Fleet-Wide Deployment:
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This report has been produced by the Manufacturing, Construction, Commissioning and Operation Working Group (MCCO WG) of the Forum during its Phase 4 of work (2024 to 2026). The report explores the conditions, strategies, and regulatory practices needed to enable fleet-wide deployment of SMRs across multiple countries and sites.
It focuses on how standardized designs, harmonized regulatory approaches, and coordinated manufacturing practices can reduce deployment barriers and support safe, efficient expansion of SMR fleets worldwide.
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here to download the report.
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The SMR Regulators' Forum is continuing work on three additional reports planned for publication in 2027:
- Continuation of 3S (safety, security and safeguards) topics (DSA)
- Construction oversight (MCCO)
- Organizational capability of a new licensee (no prior nuclear experience) (MCCO)
