Proposed Part 57 – Licensing Requirements for Microreactors and Other Reactors with Comparable Risk Profiles

Safely Enabling Rapid Licensing and High-Volume Licensing

On this page:

• Introduction
• Background
• Major Features of Proposed Part 57
• Reference Information

Introduction

Link to: Federal Register notice for the Part 57 proposed rule (91 FR 23628)

Proposed Title 10 of the Code of Federal Regulations (10 CFR) Part 57 would establish a risk-informed and performance-based regulatory framework for rapid licensing of new microreactors and other reactors with comparable risk profiles and for high-volume deployment of these reactors. The proposed rule would provide a flexible set of licensing pathways, reduce regulatory burden, and ensure that safety and security requirements remain commensurate with the potential hazards posed by these facilities.

Proposed Part 57 would enable –

• Flexibility: allows latitude in design, operation, and deployment through performance-based deterministic criteria
• Efficiency: maximizes the benefits of standardization and combining licensing applications to focus on site-specific information and reduce administrative burden
• Innovation: supports any microreactor technology and provides a variety of licensing options to meet applicants’ deployment models and use cases
   

Background

Recognizing a growing interest in microreactor deployment, the NRC staff began working on policy specifically for microreactor licensing and regulation in 2020 through a series of Commission papers (see reference information below). These papers focused on describing and proposing approaches to address technical, licensing, and other topics with new considerations for the emerging microreactor technologies and deployment models. The related Commission policy direction and interactions with hundreds of stakeholders since 2020 provided a wealth of ideas and perspectives that the NRC drew on in developing the proposed Part 57 rule and associated draft guidance.

The passage of the Accelerating Deployment of Versatile, Advanced Nuclear for Clean Energy (ADVANCE) Act of 2024 directed the NRC to develop and implement risk-informed and performance-based strategies and guidance for licensing and regulation of microreactors. In May of 2025, Executive Order 14300, “Ordering the Reform of the Nuclear Regulatory Commission” (90 FR 22587) directed the NRC to “Establish a process for high-volume licensing of microreactors and modular reactors, including by allowing for standardized applications and approvals and by considering to what extent such reactors or components thereof should be regulated through general licenses.” Proposed Part 57, along with other ongoing NRC activities, would implement these directions to enable the safe use of a wide variety of microreactor designs, operational models, and deployment strategies.
 

Major Features of Proposed Part 57

The proposed Part 57 rule would rely on streamlined safety requirements to focus on simpler license applications and rapid licensing reviews of new reactors with less complex designs and operational characteristics and low potential radiological consequences. The major provisions and features of proposed Part 57 would include the following:

• Rapid Licensing Through Streamlined Requirements – By using entry criteria and design attributes to focus on a subset of reactors, the proposed rule enables quicker licensing by focusing on simplified designs and reduced applicant submittal needs.
• High Volume Licensing – Supports issuing multiple licenses for reactors of the same standardized design across various sites in a single application.
• Rapid Deployment – Allows construction and operation approvals to occur rapidly when complete design, operational, and site information is submitted upfront.
• Multiple Licensing Pathways – Provides flexible options such as construction permits and operating licenses, manufacturing licenses, and standard design approvals to enable nearly any deployment model.
• Generic Finality – Matters previously resolved in a construction permit and operating license remain settled for subsequent similar applications.
• Manufacturing License Provisions – Allows reactors to be fabricated and fueled at manufacturing facilities with potential finality for entire designs and associated operational programs.
• Categorical Exclusions – Enables certain licensing actions to be excluded from more extensive environmental reviews when specific conditions are met.
• General License for Construction – Allows construction activities to begin before a construction permit is issued for reactor designs that have previously been built and operated.
• Alternative to 10 CFR Part 100 Siting Requirements – Permits graded site characterization using existing qualified data sources.
• Flexible Siting Approaches – A construction permit can specify many sites or large geographical areas for reactor deployment, including within population centers.
• Applicant Defined Definitions – Allows applicants to tailor regulatory definitions when justified by design specific safety analyses.
• Codes or Standards Flexibility – Lets applicants propose alternative codes and standards appropriate for their technology.
• Quality Assurance Program Flexibility – Allows use of industry approved QA programs rather than existing 10 CFR Part 50 Appendix B requirements.
• Operational Programs Standardization – Supports fleet wide use of standardized operational programs and finality for referencing by future applicants.
• Remote Monitoring/Operation/Autonomous Operation – Permits applicants to include design features and operational programs enabling off site or autonomous operation.
• Operator Licensing and Human Factors Updates – Adjusts staffing and qualification requirements to reflect potential reduced operator roles for microreactors.
• Flexible Change Processes – Streamlines some license amendment requests and allows more changes to be made without amendments.
• Readiness for Operation Finding – Streamlines authorization to operate the reactor once construction matches approved design and operational programs are in place.
• Fitness for Duty Program Flexibility – Permits applicants to propose custom fitness-for-duty programs when operator action is not safety critical.
• Resident Inspector Approach – Relies on targeted inspections rather than full time resident inspectors at licensed facilities.
• Transportation of Fueled Reactors – Allows risk based methodologies for transportation package certification.
• Decommissioning and License Termination – Enables applicants to include decommissioning plans upfront, including site-specific cost estimates and provisions for removing transportable reactors to a centralized decommissioning or refurbishment facility.
   

Reference Information

• Key documents related to the Part 57 rulemaking, including the proposed rule, associated draft guidance documents, and stakeholder comments, can be found at Regulations.gov under Docket ID NRC-2025-0379
• SECY-20-0093: Policy and Licensing Considerations related to Micro-Reactors, October 23, 2020 (Agencywide Document Access and Management System (ADAMS) Accession Number ML20254A363)
• SECY-24-0008: Micro-Reactor Licensing and Deployment Considerations: Fuel Loading and Operational Testing at a Factory, February 8, 2024 (ML23207A252)
• Staff Requirements Memorandum for SECY-24-0008, June 17, 2025 (ML25168A133)
• SECY-25-0052: Nth-of-a-Kind Microreactor Licensing and Deployment Consideration, July 3, 2025 (ML24309A266)
• Staff Requirements Memorandum for SECY-25-0052, November 13, 2025 (ML25317A650)