U.S. Nuclear Regulatory Commission Proposes New Licensing Framework for Advanced Reactors

Since the U.S. adoption of commercial nuclear power, large-scale commercial reactors — typically boiling or pressurized water designs — have been licensed under the provisions of 10 C.F.R. Part 50 (Part 50) and later 10 C.F.R. Part 52 (Part 52). Under these licensing approaches, license applicants submit construction and operating license permits in a multiyear process largely tailored to address the risks and controls necessary to operate bespoke, large-scale nuclear power plants at a specific site.

The push for a new licensing framework tailored to advanced reactors came in earnest in 2019 after Congress passed the Nuclear Energy Innovation and Modernization Act (NEIMA), which required NRC to establish a technology-inclusive framework for commercial advanced nuclear reactor applicants. NEIMA, as modified by the Accelerating Deployment of Versatile, Advanced Nuclear for Clean Energy Act of 2024 (ADVANCE Act), defines “advance nuclear reactor” as “a nuclear fission reactor or fusion machine … with significant improvements compared to commercial nuclear reactors ....” The Nuclear Regulatory Commission (NRC or Commission) considered using this term and definition to establish the scope of Part 53 but determined that “significant improvements” was not defined with enough specificity. Instead, NRC uses the broader term “commercial nuclear plant” to be technology inclusive.

Now a new generation of technology is emerging. This includes small modular reactors (SMRs) and microreactors, which are poised to be cheaper, more readily deployable, faster to construct, and simpler to operate. NRC is proposing Part 53 to address Congress’ demand for a licensing process that will accommodate these new design developments through an efficient licensing framework tailored to the new way in which nuclear power will be deployed without compromising the level of safety ensured under Parts 50 and 52 today.

The proposed rule can be found here. Following the comment period, which closes on December 30, 2024, NRC staff expects to provide the draft final rule to the Commission in 2025 and issue the final rule no later than the end of 2027.

Here are five key takeaways from the proposed rule.

1. Part 53 Establishes Licensing Framework That Is Technology-Inclusive, Risk-Informed, and Performance-Based

The Part 53 framework is broken into subparts that address the various stages of a commercial nuclear plant’s lifecycle. The licensing framework employs a probabilistic risk assessment (PRA)–led approach that builds on the Department of Energy (DOE) Licensing Modernization Project methodology. A PRA is a mathematical technique for determining what sequence of failures would be required to cause a release of radioactive material and calculating the probability that all the component failures required for that sequence to occur would actually happen.

Under Part 53, a PRA must be performed for each nuclear commercial plant to identify potential failures, susceptibility to internal and external hazards, and other contributing factors to event sequences that might challenge safety functions. This departs from the Part 50 and 52 processes, which prescribe the safety framework new reactors must be evaluated against.

The proposed approach is meant to provide flexibility for PRAs to be developed and assessed based on the application they are used to support. NRC is seeking advice on what additional guidance may be needed for PRA acceptability. Additionally, NRC is seeking recommendations on the proposed organization of Part 53 requirements and how certain provisions can be consolidated or reorganized to make the rule clearer and more concise.

2. Part 53 Includes Eight Different Types of License Applications

Under the proposed rule, there would be eight license applications.

• Early Site Permit: In the initial stage, an applicant may seek an early site permit for approval before seeking a construction permit or combined license.
• Limited Work Authorization (LWA): An applicant may also request an LWA in conjunction with an early site permit to perform specified activities.
• Standard Design Approval (SDA): An SDA provides an option for receiving approval of a final standard design for a nuclear power reactor which can be referenced in future CP, OL, COL, or ML applications.
• Standard Design Certification (SDC): An SDC provides approval of a standard design for a nuclear power facility through a rulemaking.
• Construction Permit (CP): A CP allows the license holder to construct a commercial nuclear plant. Under the proposed Part 53, a CP would be issued prior to an OL and would be converted into an OL upon completion of the facility and Commission action.
• Operating License (OL): An OL allows the license holder to operate a commercial nuclear plant. A COL combines the CP and OL and provides all necessary conditions.
• Manufacturing License (ML): An ML authorizes the manufacture of nuclear reactors. Regarding MLs, NRC has set out multiple provisions for which it requests advice and recommendations. Two of these requests are for (1) comments on the sufficiency of the proposed regulations to govern various scenarios for manufacturing and deployment of manufactured reactors and (2) comments on whether Part 53 should allow a CL or OL applicant or holder to reference an ML.

3. Part 53 Supports Efficiencies for Multiple Plants of a Common Design

NRC proposes to allow the combination of applications for multiple sites using an identical design (“common design”). This would apply to CP, OL, and COL applications with a common design, allowing one or more applicants to seek common review of a license to construct and operate nuclear power reactors located at multiple sites.

NRC is seeking comments on whether more flexibility can be added under this provision. In particular, NRC requested comments on whether this provision should consider applications that are not completely identical and, if so, what process would be used for determining whether common review would be appropriate.

4. Part 53 Modifies Standard Part 50/52 Technical Requirements in Light of New Technologies

a. Changes to Parts 26 and 73

Part 53 is supplemented by provisions in Parts 26 and 73 to enhance the safety of facilities. Under Part 26 provisions, Part 53 licensees will be required to implement Fitness for Duty Programs (e.g., drug and alcohol testing and fatigue management) no later than the start of construction to ensure that personnel at facilities are fit for duty, trustworthy, and reliable.

Part 73 will support Part 53 with alternative physical protection requirements. For certain applicants who do not meet the existing requirements under Parts 50 and 52, 10 C.F.R. § 73.100 will provide an alternative physical protection program aimed at providing assurance that activities involving special nuclear material are not inimical to the common defense and security and do not constitute an unreasonable risk to the public health and safety.

b. Comprehensive Risk Metrics

Part 53 proposes the use of comprehensive risk metrics and associated risk performance as one of several performance standards. This includes the use of individual early fatality risk, the individual latent cancer fatality risk, and the quantitative health objectives from the NRC Safety Goals Policy Statement. NRC is seeking recommendations on what other performance standards could be used to address the comprehensive risk posed by proposed commercial nuclear plants.

c. Defense in Depth

Proposed 10 C.F.R. § 53.250 would establish requirements to assess and provide defense in depth to address uncertainties of commercial nuclear plants during licensing-basis events. NRC is requesting comments on the inclusion of such requirements and whether specific provisions should be added to more explicitly address the possible role of inherent characteristics of some structures, systems, and components in preventing or mitigating unplanned events.

5. Part 53 Includes Waste Management Requirements

Part 53 establishes and details requirements for waste management throughout the lifecycle of a commercial nuclear plant. For operational requirements, § 53.850 would require every holder of an OL or COL to maintain a Radiation Protection Program and a program for the control of radioactive effluents. The program for radioactive effluents must be contained in an Offsite Dose Calculations Manual. OL and COL holders must also have a Process Control Program for solid radioactive waste processing, process parameters, and surveillance requirements.

Part 53 is poised to provide the industry with significant design and operational flexibilities to alleviate what is often viewed as a key impediment to a new “nuclear renaissance” — the inability to obtain the regulatory approvals necessary to design and build a nuclear reactor in a cost-efficient manner. While NRC expects the rulemaking won’t be final until 2027 and licensing a reactor under Part 53 comes after that, this proposed rulemaking is a significant, long-awaited step in bringing new advanced reactor technologies to market.

Law Clerk Naila M. Scott contributed to this Sidley Update.