SUPPLEMENTARY INFORMATION:

I. Obtaining information and Submitting Comments

A. Obtaining Information

Please refer to Docket ID NRC-2026-0760 when contacting the NRC about the availability of information for this action. You may obtain publicly ( printed page 20718) available information related to this action by any of the following methods:

• Federal Rulemaking Website: Go to https://www.regulations.gov and search for Docket ID NRC-2026-0760.
• NRC's Agencywide Documents Access and Management System (ADAMS): You may obtain publicly available documents online in the ADAMS Public Documents collection at https://www.nrc.gov/​reading-rm/​adams.html. To begin the search, select “Begin ADAMS Public Search.” For problems with ADAMS, please contact the NRC's Public Document Room (PDR) reference staff at 1-800-397-4209, at 301-415-4737, or by email to PDR.Resource@nrc.gov. The draft ISG, titled “NRC Application Pathway for Reactor Designs Previously Authorized by U.S. Department of Energy or Department of War,” is available in ADAMS under Accession No. ML25363A192.
• NRC's PDR: The PDR, where you may examine and order copies of publicly available documents, is open by appointment. To make an appointment to visit the PDR, please send an email to PDR.Resource@nrc.gov or call 1-800-397-4209 or 301-415-4737, between 8 a.m. and 4 p.m. eastern time (ET), Monday through Friday, except Federal holidays.

B. Submitting Comments

The NRC encourages electronic comment submission through the Federal rulemaking website ( https://www.regulations.gov). Please include Docket ID NRC-2026-0760 in your comment submission.

The NRC cautions you not to include identifying or contact information that you do not want to be publicly disclosed in your comment submission. The NRC will post all comment submissions at https://www.regulations.gov as well as enter the comment submissions into ADAMS. The NRC does not routinely edit comment submissions to remove identifying or contact information.

If you are requesting or aggregating comments from other persons for submission to the NRC, then you should inform those persons not to include identifying or contact information that they do not want to be publicly disclosed in their comment submission. Your request should state that the NRC does not routinely edit comment submissions to remove such information before making the comment submissions available to the public or entering the comment into ADAMS.

II. Discussion

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,” requires 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 E.O. 14300. Section 5(d) of the E.O. requires the NRC to establish an expedited pathway to approve reactor designs that the U.S. DOE or DOW have tested and that have demonstrated the ability to function safely.^[1] The NRC is addressing section 5(d) of this E.O. primarily through two activities, as summarized later in this document. This Federal Register notice includes one such activity. Specifically, the NRC is issuing and requesting comment on this draft ISG that would facilitate the development and review of applications for an NRC approval that seeks to leverage a prior DOE or DOW authorization.

The purpose of this draft ISG is to provide a roadmap to NRC requirements and associated guidance for areas in select, foundational areas of reactor facility safety and the protection of public health and safety. Due to the broad range of technology types and deployment options that may be authorized by DOE and DOW, this roadmap compiles NRC application requirements to aid developers while they are establishing their DOE or DOW authorization request and related NRC commercial licensing strategy. Importantly, this roadmap is not intended to be a comprehensive recitation of all applicable NRC requirements for a given requested approval. Nevertheless, upon finalization, this ISG is intended to assist prospective NRC applicants in determining how they can best maximize the overlap between what would be required to satisfy both sets of requirements ( i.e., NRC requirements and DOE or DOW requirements, as applicable). In so doing, the NRC may be able to leverage more information that has been previously reviewed and accepted by DOE or DOW when the NRC staff performs its subsequent review of a commercial application. In addition, this ISG is also intended to support a streamlined NRC review of applications in areas that include pertinent information regarding the accomplishment of safety functions related to DOE or DOW authorized reactor facilities, in which the NRC staff would appropriately adjust the focus and depth of that review when implementing the whole-of-government “leveraging” concept introduced by E.O. 14300.

While not the subject of this Federal Register notice, the other primary activity is the initiation of a separate rulemaking that proposes to amend NRC requirements in part 50 of title 10 of the Code of Federal Regulations (10 CFR), “Domestic Licensing of Production and Utilization Facilities,” and part 53, “Risk-Informed, Technology-Inclusive Regulatory Framework for Commercial Nuclear Plants,” to establish an explicit pathway for streamlined reviews for licensing commercial reactor designs that have previously received DOE or DOW authorization and that have been tested and demonstrated the ability to function safely. No change is needed for 10 CFR part 52, “Licenses, Certifications, and Approvals for Nuclear Power Plants,” as it references the requirement that is proposed to be modified in the rulemaking. The proposed rule for that activity, “NRC Reviews of Reactor Designs Previously Authorized by U.S. Department of Energy or Department of War,” was published and noticed for comment in the Federal Register on April 2, 2026. (91 FR 16584). The information in this ISG supports NRC reviews of applications under 10 CFR part 50 or part 52 pursuing the explicit pathway established by the proposed rulemaking.

Other efforts that aid in the implementation of section 5(d) of E.O. 14300 include the NRC's issuance of an addendum to the previously existing Memorandum of Understanding (MOU) titled, “Coordinating DOE and NRC Technical Expertise and Knowledge on Advanced Nuclear Reactor and Advanced Reactor Fuel Technologies,” between the NRC and DOE (ADAMS Accession No. ML25303A288). In particular, the addendum addresses coordination of DOE and NRC technical readiness and sharing of technical expertise and knowledge on advanced nuclear reactor and advanced reactor fuel technologies. The addendum also enables the documented safety analyses for DOE-authorized nuclear facilities that have been tested and that have demonstrated the ability to function safely to be leveraged to streamline and expedite future NRC licensing activities pursuant to E.O. 14300, section 5(d). Future planned activities may include the development of a crosswalk between the NRC regulations and guidance summarized in this ISG and associated ( printed page 20719) DOE authorization process requirements, and consideration and development of other MOUs, as appropriate.

III. Backfitting, Forward Fitting, and Issue Finality

This draft ISG provides guidance for the development and NRC staff review of applications for licenses, permits, certifications, or approvals under 10 CFR parts 50 and 52 that include consideration of relevant information gathered from a design that has been previously authorized by DOE or DOW as a utilization facility and that has been tested and has demonstrated the ability to function safely. Issuance of this ISG as final would not constitute backfitting as defined in 10 CFR 50.109, “Backfitting,” and as described in NRC Management Directive (MD) 8.4, “Management of Backfitting, Forward Fitting, Issue Finality, and Information Requests”; would not constitute forward fitting as that term is defined and described in MD 8.4; and would not affect the issue finality of any approval issued under 10 CFR part 52. The guidance would be for voluntary use by future applicants and would not be imposed on any current licensees or applicants or existing or requested approvals under 10 CFR parts 50 or 52, and therefore its issuance would not constitute a backfit, forward fit, or a change affecting issue finality.

IV. Executive Order (E.O.) 12866

The Office of Information and Regulatory Affairs determined that the draft ISG, titled “NRC Application Pathway for Reactor Designs Previously Authorized by U.S. Department of Energy or Department of War,” is not a significant regulatory action under E.O. 12866.

Authority:42 U.S.C. 2011 et seq.

91 FR 20717