NRC final rule lets reactor applicants build on a design's earlier Energy Department or Department of War authorization

The Nuclear Regulatory Commission has adopted a final rule that gives commercial reactor applicants a new way to show a design can perform its safety functions: by citing an earlier authorization from the Department of Energy or the Department of War.

The rule was filed for public inspection on Thursday afternoon and is scheduled for Federal Register publication on Monday, October 26. It takes effect 30 days after publication, which on that schedule is November 25.

It adds a paragraph (f) to 10 CFR 50.43 and rewrites 53.440(a)(1). An applicant may now rely on information from a reactor that either department authorized, tested and found able to function safely. It must say how that authorization satisfies NRC regulations and address any change in design, hazards, siting or safety assumptions since.

The commission says no licensing power moves. Its review stays independent.

The change answers section 5(d) of Executive Order 14300, signed May 23, 2025, which called for a faster path for designs those departments had already tested. The proposal was published April 2 and drew 136 unique comment submissions. Several commenters argued the proposed wording set a lower safety bar, so the agency moved it into its own paragraph to state that the existing standard in 50.43(e) is unchanged.

The NRC expects savings for applicants and for itself but says it could not quantify them in a useful way. The White House regulatory office classed the rule as significant, though not economically significant.