Companies that build and test reactors under Department of Energy or Pentagon authorization now have a written route to carry that work into a commercial Nuclear Regulatory Commission license. A final rule published in the Federal Register on Oct. 26 lets NRC applicants reference a prior DOE or Department of War authorization to show their designs can perform their safety functions. The change takes effect Nov. 25, 2026.
The rule, titled "NRC Reviews of Reactor Designs Previously Authorized by U.S. Department of Energy or Department of War" (RIN 3150-AL60, Docket NRC-2025-1503), amends 10 CFR 50.43 and 10 CFR 53.440. It is dated Oct. 22 and carries the signature of Jody Martin, secretary of the commission. In the preamble, the agency states its goal plainly: "The primary intent of this rulemaking is to improve NRC licensing review efficiency, and in turn increase capacity, for conducting licensing reviews."
How the New 50.43(f) Pathway Works
Section 50.43(e) already gave applicants two options to show that newer reactor designs, including those using simplified, inherent, passive or other innovative means, accomplish their safety functions. The final rule adds a third option, codified as a new paragraph (f). It applies to applications under Part 50 and Part 52, the NRC's existing licensing frameworks for power plants.
The regulatory text says an application "may include consideration of relevant information gathered from a utilization facility that has been previously authorized by the Department of Energy or the Department of Defense and that has been tested and has demonstrated the ability to function safely." Any applicant that references such a design must identify how attributes of the authorization satisfy NRC regulations.
The rule makes a parallel change to Section 53.440(a)(1), the design requirements in Part 53, the NRC's risk-informed, technology-inclusive framework for commercial plants. There, prior DOE or Pentagon test information can form part of the bases for showing that required design features meet the functional design criteria in Sections 53.410 and 53.420. A similar provision sits in a separate proposed rule for microreactors, proposed Part 57 (91 FR 23628, May 1, 2026), and would apply only if that rule is finalized.
Which Executive Order 14300 Directive Does This Rule Carry Out?
The rule addresses Section 5(d) of Executive Order 14300, "Ordering the Reform of the Nuclear Regulatory Commission," signed May 23, 2025. That section contemplates an expedited pathway to approve reactor designs that DOE or DOW have tested and that have demonstrated the ability to function safely. According to the preamble, the order 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 already addressed in DOE or DOW processes.
FedScoop reported that the NRC is calling the move "the first major change to NRC reactor regulations" since that order. NRC Chairman Ho K. Nieh said in a statement quoted by FedScoop: "High-quality applications showing how DOE and [DOD] results apply to NRC requirements will help us review them more efficiently."
What Changed After 136 Comment Submissions
The proposed rule appeared April 2, 2026, with a 30-day comment period that closed May 4. The NRC held a public meeting April 14 and received 136 unique comment submissions, according to the final rule.
FedScoop reported that supporters included The Heritage Foundation, Valar Atomics and Deep Fission, who characterized traditional licensing pathways as slow and expensive. Opponents included the Union of Concerned Scientists, the Oregon Department of Energy and the New York State Energy Research and Development Authority. They argued the rule could effectively bypass independent civilian oversight because DOD or DOE data may carry classified restrictions, and they flagged differences in risk thresholds and containment protocols compared with civilian commercial reactors.
Several commenters warned that the proposed text, then drafted as Section 50.43(e)(3), would set a lower safety standard. The NRC responded by revising that language and moving it into the new subsection 50.43(f) to "clarify and to reaffirm that this rulemaking does not alter the safety standard." Applicants must also address how changes from the prior authorization, including to design, functionality, hazards or siting, meet NRC requirements.
The agency also answered concerns that the rule would erode its independence. "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," the preamble says. It adds: "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."
The NRC also cautions that the scope of a DOE or DOW authorization or its associated testing "may not fully represent a commercial reactor configuration or the breadth of analyses necessary for an NRC licensing basis."
Can a Thinner NRC Staff Absorb the Workload?
The rule arrives as the agency's workforce shrinks. FedScoop reported that the NRC is dealing with above-normal attrition and that the White House's fiscal 2027 budget proposal outlines a plan to cut nearly 200 full-time employees.
The NRC's own qualitative economic analysis says it expects not to need to repeat technical reviews DOE or DOW already performed, to the extent they cover the same scope as the related content in an NRC application. It expects cost savings for both applicants and the agency but says it "was not able to quantify these potential savings in a useful way at this time." The Office of Information and Regulatory Affairs deemed the rule significant but not economically significant, and the NRC classifies it as a deregulatory action under Executive Order 14192.
What It Means for Contractors
For firms building reactors under DOE and Pentagon demonstration programs, the rule creates a regulatory bridge from a federal prototype to a commercial NRC license. Test data, analyses and operating experience generated under a government authorization can now be cited in an NRC application, rather than reproduced from scratch.
The benefit depends on the paperwork. The preamble says 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." The NRC suggests applicants describe the scope of the prior authorization, including testing, analyses and operational experience; the safety functions and design features it addressed; and any design, operational or siting differences material to the licensing review.
Firms should also watch the companion guidance. The NRC published draft Interim Staff Guidance, DANU-ISG-2026-XX, for comment on April 17, 2026 (91 FR 20717), and says new guidance documents will be available under Docket NRC-2026-0760. Because the option applies only to future applicants, the NRC says the changes do not constitute backfitting for existing licensees. Companies planning to move a demonstration design into commercial service should structure their DOE or DOW test records now with an NRC licensing basis in mind.
