This publication has been issued for public comment. Comments will be accepted until November 9, 2026. To submit comments, please see Docket ID Number NRC-2025-1138.
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Publication Information
Manuscript Completed: April 2026
Date Published: September 2026
Prepared by:
B. Purnell
A. Klett
H. Benowitz
Office of Nuclear Reactor Regulation
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001
Abstract
NUREG-1409, “Backfitting Guidelines,” Revision 1, provides guidance to the U.S. Nuclear Regulatory Commission (NRC) staff on the implementation of the backfitting and issue finality provisions in Title 10 of the Code of Federal Regulations (10 CFR) Chapter I and the backfitting, issue finality, and forward fitting policies described in Management Directive 8.4, “Management of Backfitting, Forward Fitting, Issue Finality, and Information Requests.”
Backfitting occurs when the NRC imposes new or changed regulatory requirements or staff interpretations of the regulations or requirements on nuclear power reactor licensees, certain nuclear power reactor applicants, or select nuclear materials licensees. Backfitting is an integral part of the regulatory process and may be needed when the staff addresses safety or security issues. The NRC may take a backfitting action only after conducting a formal, systematic review to ensure that the action is defined and justified. This process ensures discipline, predictability, and optimal use of NRC, licensee, and applicant resources. The backfitting requirements are in 10 CFR 50.109, 53.1590, 70.76, and 72.62, all titled, “Backfitting.” Provisions analogous to the backfitting requirements, referred to as issue finality provisions, appear in 10 CFR Part 52, “Licenses, Certifications, and Approvals for Nuclear Power Plants,” and 10 CFR Part 53, “RiskInformed Technology-Inclusive Regulatory Framework for Commercial Nuclear Plants.”
Forward fitting occurs when the NRC conditions its approval of a licensee-initiated request for a licensing action on the licensee’s compliance with a new or modified requirement or staff interpretation of a requirement that the licensee did not request. Commission policy allows forward fitting only when specific criteria are met. The guidelines in this NUREG support the staff’s identification of potential forward fitting actions and provide methods to address the underlying safety or security issue without forward fitting. These guidelines are consistent with current licensing practices and procedures and do not support forward fitting because these guidelines are a more efficient and effective way of ensuring NRC staff compliance with the Commission's forward fitting policy.
The NRC issued the previous version of this NUREG in 1990, but the 1990 document did not address the backfitting requirements in 10 CFR Part 53, 10 CFR Part 70, “Domestic Licensing of Special Nuclear Material,” and 10 CFR Part 72, “Licensing Requirements for the Independent Storage of Spent Nuclear Fuel, High-Level Radioactive Waste, and Reactor-Related Greater Than Class C Waste”; the issue finality provisions in 10 CFR Part 52 and 10 CFR Part 53; the Commission’s forward fitting policy in Management Directive 8.4; or the applicability of backfitting to commercial non-power production or utilization facilities licensed under Section 103 of the Atomic Energy Act of 1954, as amended, most of which were developed after 1990. This update of NUREG-1409 is a substantial revision to the 1990 document and addresses all backfitting and issue finality provisions in the regulations listed above and the Commission’s backfitting, issue finality, and forward fitting policies.