Key Takeaways
What Happened: The U.S. Nuclear Regulatory Commission (NRC) issued draft interim staff guidance (ISG or draft guidance), DANU-ISG-2026-XX, “NRC Application Pathway for Reactor Designs Previously Authorized by U.S. Department of Energy or Department of War,” and requested public comments by May 18, 2026. The draft guidance is part of the NRC’s plan to establish an expedited pathway for NRC review and licensing of reactor designs previously authorized and tested by the Department of Energy (DOE) or Department of War (DOW). The NRC anticipates allowing applicants to use this approach for entire reactor facility designs or major portions thereof that DOE or DOW has previously authorized .
Who’s Impacted: Advanced nuclear reactor developers, DOE or DOW demonstration project participants, utilities, investors, technology vendors, and other stakeholders considering a commercial NRC licensing strategy after having already received DOE or DOW authorization.
What Should They Do: Stakeholders should consider incorporating ISG information into their strategies for applying for and obtaining DOE or DOW and NRC approvals. Stakeholders should also consider commenting on how the NRC could improve and clarify the draft guidance to maximize efficiency in its review of previously approved reactor designs.
When Should They Act: Comments on the draft ISG are due May 18, 2026. Comments on the NRC’s related proposed rule are due May 4, 2026.
The NRC Proposes Guidance to Support Streamlined Reviews
The draft guidance is part of the NRC’s effort to implement Executive Order 14300, which directs the NRC to establish an expedited pathway for reactor designs that DOE or DOW has tested and that have demonstrated the ability to function safely. The NRC designed the draft ISG to provide a practical roadmap for carrying DOE or DOW authorization materials into a later NRC application.
The ISG would not replace or change NRC licensing requirements. Nor would the ISG dictate precisely how NRC staff consider or apply prior DOE or DOW authorizations to the NRC licensing process. Instead, it would guide applicants on how to organize and present prior DOE or DOW authorization materials so the NRC can determine whether, and to what extent, those materials satisfy NRC requirements. The intended outcome is a coordinated approach among NRC and DOE or DOW to facilitate licensing and deployment efficiencies by avoiding the need for multiple agencies’ technical staff to review the same content when assessing the risk associated with newly-proposed commercial reactor facilities. This approach would enable the NRC to “appropriately adjust the focus and depth of its technical review for attributes of the design reviewed in DOE or DOW authorizations.” An applicant would still need to submit a complete application and demonstrate compliance with all applicable NRC regulatory requirements.
The draft ISG applies to applications for construction permits and operating licenses under 10 CFR Part 50, as well as combined licenses, manufacturing licenses, standard design approvals, and design certifications under 10 CFR Part 52. Interestingly, the draft guidance does not apply to applicants for NRC approvals under the new framework for advanced reactors, 10 CFR Part 53, something stakeholders should consider commenting on. The NRC also states that the guidance may help applicants who are not pursuing DOE or DOW authorization, because it collects NRC expectations in key foundational safety areas.
Developers Should Plan for NRC Licensing During DOE/DOW Authorization Process
The draft ISG encourages developers to plan for NRC licensing before or during the DOE or DOW authorization process. Accordingly, developers seeking to use this pathway should build their DOE or DOW submissions with the future NRC licensing case in mind. That includes identifying where DOE or DOW analyses may overlap with NRC requirements and where supplemental NRC-specific analysis will likely be necessary.
The ISG identifies three features that NRC views as central to efficient leveraging:
- Early alignment. Developers should consider NRC requirements and guidance when preparing DOE or DOW authorization materials.
- Preapplication engagement. Developers should engage the NRC early, preferably while the DOE or DOW authorization effort is underway.
- Core team review. The NRC expects its “core team” review approach to help reduce review time and resources by focusing staff review on the most important technical and regulatory issues.
Key Technical Areas Covered
The draft ISG organizes the roadmap of NRC requirements around three broad reactor design categories: (1) light-water reactor technologies using a traditional deterministic approach; (2) non-light-water reactor technologies using a traditional deterministic approach; and (3) non-light-water reactor technologies using a risk-informed and performance-based approach reflected in NRC Regulatory Guide 1.233.
The draft ISG’s appendices address 10 topics which form much of the foundation for assessment of reactor facility risk and documentation of the facility’s associated safety basis, which the NRC anticipates may overlap with many of the DOE or DOW authorization requirements:
- Quality Assurance Program
- Licensing Event Selection and Classification of Structures, Systems, and Components
- Principal Design Criteria
- Source Term
- Consequence Analysis
- Emergency Preparedness
- Security
- Fire Protection Requirements
- Technical Specifications
- Site Characterization and Design for External Hazards
For each area, the ISG summarizes relevant NRC requirements, application content guidance, staff review guidance, and directs staff to utilize, as appropriate, DOE or DOW authorization materials and reviews. The ISG, however, does not dictate exactly how the NRC’s staff will apply prior DOE or DOW analyses and approvals to evaluate compliance with NRC requirements for each of these 10 topics. Instead, the ISG directs staff to “leverage prior DOE or DOW authorizations in its review” of compliance in each of these 10 areas.
Relationship to the NRC’s Proposed Rule
The draft ISG complements the NRC’s separate proposed rule on reactor designs previously authorized by DOE or DOW. That proposed rule would revise 10 CFR Parts 50 and 53 to facilitate direct leveraging of prior DOE or DOW authorizations in NRC licensing reviews. The NRC describes the ISG as supporting reviews under Parts 50 and 52 for applications that pursue the pathway contemplated by the rulemaking.
Stakeholders should consider commenting on both the proposed rule and the draft ISG.
How To Submit Comments
The NRC encourages electronic comments through the federal rulemaking website. To comment on the draft ISG, commenters should search for Docket ID NRC-2026-0760 or use the Regulations.gov docket page. Commenters may also mail comments to: Office of Administration, Mail Stop: TWFN-5-A85, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, ATTN: Program Management, Announcements and Editing Staff.
To comment on the separate proposed rule, commenters should search for Docket ID NRC-2025-1503 or use the Regulations.gov docket page.
Commenters should avoid including identifying, contact, confidential, or sensitive business information that they do not want publicly disclosed. The NRC states that it will post comment submissions publicly, and that it does not routinely edit submissions to remove identifying or contact information.
