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Acceptance of Commercial-Grade Design and Analysis Computer Programs for Nuclear Power Plants

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Nuclear Regulatory Commission.


Regulatory Guide; issuance.


The U.S. Nuclear Regulatory Commission (NRC) is issuing Revision 0 to Regulatory Guide (RG) 1.231, “Acceptance of Commercial-Grade Design and Analysis Computer Programs for Nuclear Power Plants.” This RG describes methods that the NRC considers acceptable in meeting regulatory requirements for acceptance and dedication of commercial-grade design and analysis computer programs used in safety-related applications for nuclear power plants.


Revision 0 to RG 1.231 is available on December 29, 2016.


Please refer to Docket ID NRC-2015-0153 when contacting the NRC about the availability of information regarding this document. You may obtain publically-available information related to this document, using the following methods:

  • Federal Rulemaking Web site: Go to and search for Docket ID NRC-2016-0153. Address questions about NRC dockets to Carol Gallagher; telephone: 301-415-3463; email: For technical questions, contact the individuals listed in the FOR FURTHER INFORMATION CONTACT section of this document.
  • NRC's Agencywide Documents Access and Management System (ADAMS): You may obtain publicly-available documents online in the ADAMS Public Document collection at​reading-rm/​adams.html. To begin the search, select “ADAMS Public Documents” and then select “Begin Web-based ADAMS Search.” For problems with ADAMS, please contact the NRC's Public Document Room (PDR) reference staff at 1-800-397-4209, 301-415-4737, or by email to The ADAMS accession number for each document referenced in this notice (if that document is available in ADAMS) is provided the first time that a document is referenced. Revision 0 to Regulatory Guide 1.231, and the regulatory analysis may be found in ADAMS under Accession Nos. ML16126A183 and ML16126A181 respectively.
  • NRC's PDR: You may examine and purchase copies of public documents at the NRC's PDR, Room O1-F21, One White Flint North, 11555 Rockville Pike, Rockville, Maryland 20852.

Regulatory guides are not copyrighted, and the NRC's approval is not required to reproduce them.

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Greg Galletti, Office of New Reactors, telephone: 301-415-1831; email:; and Stephen Burton, Office of Nuclear Regulatory Research, telephone: 301-415-7000; email: Both are staff of the U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001.

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I. Introduction

The NRC is issuing a new guide in the NRC's “Regulatory Guide” series. This series was developed to describe and make available to the public information regarding methods that are acceptable to the NRC for implementing specific parts of the agency's regulations, techniques that the NRC uses in evaluating specific issues or postulated events, and data that the NRC needs in its review of applications for permits and licenses.

Revision 0 of RG 1.231 was issued with a temporary identification of Draft Regulatory Guide, DG-1305. This RG is being issued to endorse Revision 1 of EPRI Technical Report 1025243, “Plant Engineering: Guideline for the Acceptance of Commercial-Grade Design and Analysis Computer Programs Used in Nuclear Safety-Related Applications,” with respect to acceptance of commercial-grade design and analysis computer programs associated with basic components for nuclear power plants.

II. Additional Information

The NRC published a notice of the availability of DG-1305 in the Federal Register on July 1, 2015, (80 FR 37666) for a 60-day public comment period. The public comment period closed on August 31, 2015. Public comments on DG-1305 and the NRC's responses to the public comments are available in ADAMS under Accession No. ML16126A179.

III. Congressional Review Act

This regulatory guide is a rule as defined in the Congressional Review Act (5 U.S.C. 801-808). However, the Office of Management and Budget has not found it to be a major rule as defined in the Congressional Review Act.

IV. Backfitting and Issue Finality

This regulatory guide describes acceptable methods for meeting the dedication requirements in part 21 of title 10 of the Code of Federal Regulations (10 CFR) and § 50.55(e) with respect to design and analysis computer programs for nuclear power plants. The regulatory guide, does not constitute backfitting as defined in 10 CFR 50.109 (the Backfit Rule) and is not otherwise inconsistent with the issue finality provisions in 10 CFR part 52, “Licenses, Certifications and Approvals for Nuclear Power Plants.” This regulatory guide, if finalized, represents the first NRC guidance on this subject. Issuance of new guidance, by itself, does not represent backfitting unless the NRC intends to impose the guidance on existing licensees and currently-approved design certification rules issued under 10 CFR part 52. The NRC does not have such an intention.

Existing licensees and applicants of final design certification rules will not be required to comply with the positions set forth in this regulatory guide, unless the licensee or design certification rule applicant seeks a voluntary change to its licensing basis with respect to safety-related power operated valve actuators, and where the NRC determines that the safety review must include consideration of the qualification of the valve actuators. Further information on the NRC's use of the regulatory guide, is contained in the regulatory guide under Section D. Implementation.

Applicants and potential applicants are not, with certain exceptions, protected by either the Backfit Rule or any issue finality provisions under 10 CFR part 52. Neither the Backfit Rule nor the issue finality provisions under 10 CFR part 52—with certain exclusions Start Printed Page 96051discussed below—were intended to every NRC action which substantially changes the expectations of current and future applicants. Therefore, the positions in any final regulatory guide, if imposed on applicants, would not represent backfitting (except as discussed below).

The exceptions to the general principle are applicable whenever a combined license applicant references a 10 CFR part 52 license (i.e., an early site permit or a manufacturing license) and/or 10 CFR part 52 regulatory approval (i.e., a design certification rule or design approval). The NRC does not, at this time, intend to impose the positions represented in the regulatory guide in a manner that is inconsistent with any issue finality provisions in the 10 CFR part 52 licenses and regulatory approvals. If, in the future, the NRC seeks to impose a position in this regulatory guide in a manner which does not provide issue finality as described in the applicable issue finality provision, then the NRC must address the criteria for avoiding issue finality as described in the applicable issue finality provision.

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Dated at Rockville, Maryland, this 23rd day of December 2016.

For the Nuclear Regulatory Commission.

Edward O'Donnell,

Acting Chief, Regulatory Guidance and Generic Issues Branch, Division of Engineering, Office of Nuclear Regulatory Research.

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[FR Doc. 2016-31603 Filed 12-28-16; 8:45 am]