SUPPLEMENTARY INFORMATION:

Table of Contents

I. Executive Order 14300: Ordering the Reform of the Nuclear Regulatory Commission

II. Discussion

III. Opportunities for Public Participation

IV. Public Comment Analysis

V. Regulatory Flexibility Certification

VI. Regulatory Analysis

VII. Backfitting and Issue Finality

VIII. Cumulative Effects of Regulation

IX. Plain Writing

X. National Environmental Policy Act

XI. Paperwork Reduction Act

XII. Executive Orders

A. Executive Order 12866: Regulatory Planning and Review (as Amended by Executive Order 14215, Ensuring Accountability for All Agencies)

B. Executive Order 14154: Unleashing American Energy

C. Executive Order 14192: Unleashing Prosperity Through Deregulation

D. Executive Order 14270: Zero-Based Regulatory Budgeting To Unleash American Energy

XIII. Congressional Review Act

XIV. Voluntary Consensus Standards

XV. Availability of Guidance

XVI. Availability of Documents

I. Executive Order 14300: Ordering the Reform of the Nuclear Regulatory Commission

On May 23, 2025, President Donald J. Trump signed Executive Order (E.O.) 14300, “Ordering the Reform of the Nuclear Regulatory Commission.” Section 5, “Reforming and Modernizing the NRC's Regulations,” directed the NRC to undertake a review and wholesale revision of its regulations and guidance documents as guided by the policies set forth in section 2 of the E.O. This rulemaking addresses section 5(d), which contemplates an expedited pathway to approve reactor designs that the U.S. Department of Energy (DOE) or the Department of War (DOW) have tested and that have demonstrated the ability to function safely.^[1] E.O. 14300 further states that NRC review of such designs should focus solely on risks that may arise from new applications permitted by NRC licensure, rather than revisiting risks that have already been addressed in the DOE or DOW processes.

II. Discussion

Consistent with its authority and historical practice under section 161 of the Atomic Energy Act of 1954 (AEA) to make, promulgate, issue, rescind, and amend rules and regulations as well as that under section 182 of the AEA to determine the information that enables the Commission to make the findings required to grant an application for a utilization facility, the NRC is amending title 10 of the Code of Federal Regulations (10 CFR) section 50.43, “Additional standards and provisions affecting class 103 licenses and certifications for commercial power,” and section 53.440, “Design requirements.” These changes explicitly establish a pathway for streamlined reviews for licensing commercial reactor designs that have previously received ( printed page 67196) DOE or DOW authorization and that have been tested and have demonstrated the ability to function safely. The amendment to § 50.43 explicitly establishes such a pathway for the licensing frameworks under 10 CFR part 50, “Domestic Licensing of Production and Utilization Facilities,” and part 52, “Licenses, Certifications, and Approvals for Nuclear Power Plants,” and the amendment to § 53.440 does so for the 10 CFR part 53, “Risk-Informed, Technology-Inclusive Regulatory Framework for Commercial Nuclear Plants,” licensing framework. A similar provision is included in a separate proposed rule, “Licensing Requirements for Microreactors and Other Reactors With Comparable Risk Profiles,” which, if finalized, would apply to the associated proposed 10 CFR part 57, “Licensing Requirements for Microreactors and Other Reactors with Comparable Risk Profiles,” licensing framework (91 FR 23628; May 1, 2026). The primary intent of this rulemaking is to improve NRC licensing review efficiency, and in turn increase capacity, for conducting licensing reviews. At the same time, this rulemaking maintains flexibility for the NRC to leverage a broad range of technologies, testing methods, and information from previously authorized and evaluated designs, as appropriate and supported by an applicant in its commercial license application. In turn, this contributes to the safe and secure use and deployment of civilian nuclear energy technologies.

Section 50.43(e) provides two options for license applicants to demonstrate how newer reactor designs, including those that use simplified, inherent, passive, or other innovative means, accomplish their safety functions. The final rule adds the option, to be codified in § 50.43(f), for an applicant to reference information from a prior DOE or DOW authorization as a means for an NRC license applicant to show that the design can accomplish its safety functions, as required by § 50.43(e).

The amendment to § 50.43 explicitly reflects the option for NRC Class 103 license applicants to directly reference a prior DOE or DOW authorization when demonstrating compliance with NRC regulatory requirements. Applicants using this option are required to identify how aspects of the prior authorization satisfy NRC regulations, including § 50.43(e). Applicants are also required to address how any changes to the design, its functionality, associated hazards, siting information, or underlying safety assumptions from those considered in prior authorization reviews meet applicable NRC requirements.

Under the part 53 licensing framework, § 53.440 provides a series of design requirements. The requirements in § 53.440(a)(1) reflect an essential element of ensuring a proposed design can comply with the performance criteria in part 53, namely that the abilities of design features to fulfill their safety functions are demonstrated by a combination of analyses, test programs, prototype testing, and operating experience. This requirement closely aligns with the language in § 50.43(e) and reflects the same foundational requirement.

The amendment to § 53.440(a)(1) explicitly accommodates the option for NRC Class 103 license applicants to directly reference a prior DOE or DOW authorization for the purpose of demonstrating that the design features required by § 53.400, “Design features for licensing-basis events” meet the defined functional design criteria required by §§ 53.410, “Functional design criteria for design-basis accidents,” and 53.420, “Functional design criteria for licensing-basis events other than design-basis accidents.” Such a demonstration is required to consider interdependent effects throughout the commercial nuclear plant and the range of conditions under which the design features required by § 53.400 must function throughout the plant's lifetime. Applicants using this option are required to identify how aspects of the prior authorization satisfy applicable NRC regulations.

The new §§ 50.43(f) and 53.440(a)(1) pathways will be supported by the draft Interim Staff Guidance (ISG), DANU-ISG-2026-XX, “NRC Application Pathway for Reactor Designs Previously Authorized by U.S. Department of Energy or Department of War.” The guidance is not part of this rulemaking but was published for public comment on April 17, 2026 (91 FR 20717). The scope of such guidance is intended to facilitate staff review of future commercial nuclear plant license applications, including advanced reactor designs that may not employ light-water technology.

The NRC also recognizes significant public interest in this rule and has provided a separate public comment response document as discussed in Section IV of this document, “Public Comment Analysis.” While that document provides comprehensive responses to comments, several points are highlighted below.

Some comments expressed concern that this rulemaking would impact the NRC's performance of independent evaluations of license applications mandated under the AEA. Specifically, section 103 of the AEA and title II of the Energy Reorganization Act of 1974 (88 Stat. 1242) authorize the NRC to, among other things, issue licenses for commercial nuclear power plants if in the opinion of the Commission, issuance of the license would not be inimical to the common defense and security or to the health and safety of the public. First and foremost, this rulemaking does not affect the NRC's commitment to conducting independent reviews, nor does this rulemaking alter any underlying regulatory requirements an applicant must meet. Nothing in this rule delegates to DOE, DOW, or any other agency the NRC's functions to evaluate a request for NRC approval, and nothing in this rule allows the NRC to forego an independent review. Regardless of whether an applicant references a prior DOE or DOW authorization, it remains the applicant's responsibility to demonstrate compliance with all applicable requirements, under the AEA and NRC regulations, and the NRC will continue to conduct the independent assessments necessary to confirm whether such requirements have indeed been satisfied. Where an NRC applicant references information from a prior design authorized and tested by DOE or DOW, the applicant is responsible for justifying the applicability and relevance of the information it seeks to rely upon, and where it does so, the NRC may be able to tailor the focus and depth of its review.

Under this approach, the NRC notes that the extent to which prior DOE or DOW information can be leveraged depends on the information an applicant provides and the associated justification as to how it meets NRC requirements. For example, the scope of a DOE or DOW authorization or associated testing may not fully represent a commercial reactor configuration or the breadth of analyses necessary for an NRC licensing basis. The final rule is intentionally structured to reflect that not all prior DOE or DOW authorizations may meet the full scope of requirements specified in § 50.43 and, in recognition of this, to nevertheless make clear that the NRC retains the flexibility to leverage information from such authorizations to the maximum extent practical.

In addition, some comments highlighted that it would be beneficial for the NRC to provide additional clarity as to the type of information an NRC application might include in a discussion of how a prior DOE or DOW authorization supports the application. ( printed page 67197) In light of these comments, the NRC is clarifying that, when demonstrating compliance with applicable regulations, an NRC applicant may, for example, consider including a discussion of the following: (A) the scope of the prior authorization, including the testing, analyses, and operational experience on which it relied, as applicable; (B) the safety functions and design features addressed by such authorization; and (C) any differences from the prior authorization in design, operational, or siting factors relevant to the application that are material to the Commission's licensing review.

Finally, several commenters expressed concerns that the proposed § 50.43(e)(3) would establish a lower safety standard than that required by § 50.43(e)(1)-(2) and § 53.440(a)(1). As explained in the public comment response document, the NRC has revised the language originally proposed to be codified in § 50.43(e)(3) and has added it as a new subsection § 50.43(f) to clarify and to reaffirm that this rulemaking does not alter the safety standard established in§ 50.43(e) and to enhance consistency with the approach taken in the rule revision to § 53.440(a)(1). As such, the final rule language makes clear that § 50.43(f) is one option that a commercial license applicant may use to satisfy the requirements, or a subset of the requirements, contained in section(e). As previously noted, applicants must still meet all applicable NRC and statutory requirements. Although § 50.43(f) provides a pathway for reactor technologies to demonstrate the ability to accomplish safety functions under § 50.43(e), if an authorization does not supply all necessary information, the final rule language in § 50.43(f) reflects that applicants must address any remaining gaps to ensure full compliance with NRC requirements.

III. Opportunities for Public Participation

The proposed rule was published in the Federal Register on April 2, 2026 (91 FR 16584) for a 30-day comment period ending May 4, 2026. The NRC held a public meeting on April 14, 2026, and developed a public meeting summary (ML26131A245).

IV. Public Comment Analysis

The NRC prepared a summary and analysis of public comments (“NRC Response to Public Comments: NRC Reviews of Reactor Designs Previously Authorized by U.S. Department of Energy or Department of War”) received on the proposed rule, as referenced in the “Availability of Documents” section. In response to the proposed rule, the NRC received 136 unique comment submissions.

The public comment submissions are available from the Federal rulemaking website at www.regulations.gov under Docket ID NRC-2025-1503. Responses to the public comments, including a summary of how this final rule changed as a result of the public comments, can be found in the public comment response document as indicated in the “Availability of Documents” section of this document.

V. Regulatory Flexibility Certification

Under the Regulatory Flexibility Act (5 U.S.C. 605(b)), the NRC certifies that this rule does not have a significant economic impact on a substantial number of small entities. This final rule affects only the licensing and operation of nuclear power plants. The companies that own these plants do not fall within the scope of the definition of “small entities” set forth in the Regulatory Flexibility Act or the size standards established by the NRC (10 CFR 2.810).

VI. Regulatory Analysis

The NRC has not prepared a separate regulatory analysis. However, the NRC performed a qualitative economic analysis of the rule's impacts. As a result of this final rule, the NRC expects that the NRC will not need to repeat technical reviews previously performed by DOE or DOW, to the extent that those reviews cover the same scope as the related content in the NRC license application. The final rule language at § 50.43(f) offers an option to meet the requirements in § 50.43(e), and the final rule language in § 53.440(a) provides an option for how to demonstrate that the design features required by § 53.400 meet the design criteria required by §§ 53.410 and 53.420. Therefore, the NRC does not anticipate that an application under the new § 50.43(f) or the revised § 53.440(a)(1) would require more review work than under the existing requirements. Furthermore, the NRC assumes that applications under these sections will be high-quality applications.

In general, the NRC expects cost savings to both applicants in preparing an application and the NRC in reviewing that application. The NRC was not able to quantify these potential savings in a useful way at this time. These savings depend on the applicability of the DOE/DOW reviews to NRC requirements and the ability of applicants to demonstrate that applicability, the number of applications that may reference a previous DOE/DOW authorization, as well as how any potential differences ( e.g., changes to the design or site-specific factors) from the previously authorized design also meet NRC requirements. The NRC anticipates that use of the approaches provided by § 50.43(f) or 53.440(a)(1) will become more efficient as experience is gained, i.e., there may be an initial learning curve which may result in greater cost savings over time, to both the NRC and applicants, as a result of the additional flexibility this final rule provides to applicants. Therefore, the NRC expects that this final rule will be cost beneficial to both the NRC and future applicants.

VII. Backfitting and Issue Finality

The changes to §§ 50.43(f) and 53.440(a)(1) do not impose new or revised requirements on existing licensees or approval holders because they include an option that would apply only to future applicants. Therefore, the changes do not constitute backfitting as defined in § 50.109(a)(1) or 53.1590(a)(1) or affect the issue finality of an existing approval issued under 10 CFR part 52, “Licenses, Certifications, and Approvals for Nuclear Power Plants.”

VIII. Cumulative Effects of Regulation

The NRC seeks to minimize any potential negative consequences resulting from the cumulative effects of regulation (CER). The CER describes the challenges that licensees, or other impacted entities such as State partners, may face while implementing new regulatory positions, programs, or requirements ( e.g., rules, generic letters, backfits, inspections). The CER is an organizational effectiveness challenge that may result from a licensee or impacted entity implementing a number of complex regulatory actions, programs, or requirements within limited available resources.

The goals of the NRC's CER effort were met throughout the development of this final rule. The NRC engaged with external stakeholders at a public meeting and solicited public comments on the proposed rule. The NRC included in the proposed rule a request for feedback related to CER. Specifically, the NRC requested feedback on the implementation and potential unintended consequences of the proposed rule, and invited comments on the regulatory analysis. The NRC received several comment submissions in response to these CER questions, which are addressed in the public comment response document as indicated in the “Availability of Documents” section of this document. ( printed page 67198)

IX. Plain Writing

The Plain Writing Act of 2010 (Pub. L. 111-274) requires Federal agencies to write documents in a clear, concise, and well-organized manner. The NRC has written this document to be consistent with the Plain Writing Act as well as the Presidential Memorandum, “Plain Language in Government Writing,” published June 10, 1998 (63 FR 31885).

X. National Environmental Policy Act

The NRC has determined that this final rule is the type of action eligible for categorical exclusion because it meets the criterion described in § 51.22(a)(1). This provision includes amendments to parts 50 and 53 related to procedures for filing and reviewing applications for licenses or construction permits or early site permits or other forms of permission or for amendments to or renewals of licenses or construction permits or early site permits or other forms of permission. The action belongs to a category of actions that the Commission, by rule or regulation, has declared to be a categorical exclusion, after first finding that the actions within the category do not individually or cumulatively have a significant effect on the human environment. Therefore, neither an environmental impact statement nor environmental assessment has been prepared for this final rule. For any particular licensing action that would use the pathways from this rule, the NRC will comply with its obligations under the National Environmental Policy Act, including by developing or using an environmental impact statement, environmental assessment, or categorical exclusion, as applicable.

XI. Paperwork Reduction Act

This final rule does not contain any new or amended collections of information subject to the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.). Existing collections of information were approved by the Office of Management and Budget (OMB), approval numbers 3150-0011 and 3150-0274.

Public Protection Notification

The NRC may not conduct or sponsor, and a person is not required to respond to, a collection of information unless the document requesting or requiring the collection displays a currently valid OMB control number.

XII. Executive Orders

The following are Executive orders that are related to this final rule:

A. Executive Order 12866: Regulatory Planning and Review (as Amended by Executive Order 14215, Ensuring Accountability for All Agencies)

E.O. 12866 provides that the Office of Information and Regulatory Affairs (OIRA) within the OMB will review all significant rules. OIRA has determined that this final rule is a significant regulatory action under section 3(f) of E.O. 12866; though not economically significant under section 3(f)(1). Accordingly, the NRC submitted this final rule to OIRA for review. The NRC has prepared an economic analysis in accordance with section 6(a)(3)(B) of E.O. 12866. More can be found in Section VI, of this document, “Regulatory Analysis.”

B. Executive Order 14154: Unleashing American Energy

NRC has examined this final rule and has determined that it is consistent with the policies and directives outlined in E.O. 14154.

C. Executive Order 14192: Unleashing Prosperity Through Deregulation

This action is a deregulatory action as defined by E.O. 14192. Details on the estimated costs of this final rule can be found in Section VI of this document, “Regulatory Analysis.”

D. Executive Order 14270: Zero-Based Regulatory Budgeting To Unleash American Energy

E.O. 14270, “Zero-Based Regulatory Budgeting to Unleash American Energy,” requires the NRC to insert a conditional sunset date into all new or amended NRC regulations provided the regulations are (1) promulgated under the AEA, the Energy Reorganization Act of 1974, as amended (ERA), or the Nuclear Waste Policy Act of 1982, as amended (NWPA); (2) not statutorily required; and (3) not part of the NRC's permitting regime. The NRC determined that the regulatory changes proposed in this rule are part of the NRC's regulatory permitting scheme authorized by the AEA, ERA, or NWPA. Therefore, the NRC views this rulemaking to be outside the scope of E.O. 14270 and did not insert conditional sunset dates for the regulatory changes in this final rule.

XIII. Congressional Review Act

This final rule is a rule as defined in the Congressional Review Act (5 U.S.C. 801-808). However, OMB has found that it does not meet the criteria at 5 U.S.C. 804(2).

XIV. Voluntary Consensus Standards

The National Technology Transfer and Advancement Act of 1995, Public Law 104-113, requires that Federal agencies use technical standards that are developed or adopted by voluntary consensus standards bodies unless the use of such a standard is inconsistent with applicable law or otherwise impractical. In this final rule, the NRC revised its regulations to facilitate direct leveraging of prior DOE or DOW authorizations of demonstration reactors into the NRC's licensing reviews of commercial reactor facility applications that utilize those designs. This action does not constitute the establishment of a standard that contains generally applicable requirements.

XV. Availability of Guidance

The NRC will be issuing new guidance for the implementation of the amendments in this rulemaking. The NRC will publish Federal Register notices announcing the availability of the new guidance documents. The documents will be available at www.regulations.gov by searching on Docket ID NRC-2026-0760.

XVI. Availability of Documents

The documents identified in the following table are available to interested persons through one or more of the following methods, as indicated.

The NRC may post materials related to this document, including public comments, on the Federal rulemaking website at www.regulations.gov under Docket ID NRC-2025-1503. In addition, the Federal rulemaking website allows members of the public to receive alerts when changes or additions occur in a docket folder. To subscribe: (1) navigate to the docket folder (NRC-2025-1503); (2) click the “Subscribe” button; and (3) enter an email address and click on the “Subscribe” button.

For the reasons set out in the preamble and under the authority of the Atomic Energy Act of 1954, as amended; the Energy Reorganization Act of 1974, as amended; and 5 U.S.C. 552 and 553, the NRC is adopting the following amendments to 10 CFR parts 50 and 53:

91 FR 67195