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Protection Against Extreme Wind Events and Missiles for Nuclear Power Plants

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Nuclear Regulatory Commission.


Regulatory guide; issuance.


The U.S. Nuclear Regulatory Commission (NRC) is issuing Revision 2 to Regulatory Guide (RG) 1.117, Protection Against Extreme Wind Events and Missiles for Nuclear Power Plants.” This RG describes an approach that the NRC staff considers acceptable for identifying those structures, systems, and components of light water cooled reactors that should be protected from the effects of the worst case extreme winds and wind-generated missiles, so they remain functional.


Revision 2 to RG 1.117 is available on July 13, 2016.


Please refer to Docket ID NRC-2015-0202 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-2015-0202. 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 (if it is available in Start Printed Page 45312ADAMS) is provided the first time that it is mentioned in this document. Revision 2 to Regulatory Guide 1.117, and the regulatory analysis may be found in ADAMS under Accession No. ML15356A213 and ML14356A106, 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 NRC approval is not required to reproduce them.

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Gordon Curran, Office of Nuclear Reactor Regulation, telephone: 301-415-1247, email:; and Stephen Burton, Office of Nuclear Regulatory Research, telephone: 301-415-7000, email: Both are staff members of the U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001.

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I. Introduction

The NRC is issuing a revision to an existing 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 staff for implementing specific parts of the agency's regulations, techniques that the NRC staff uses in evaluating specific issues or postulated events, and data that the NRC staff needs in its review of applications for permits and licenses.

Revision 2 of RG 1.117 was issued with a temporary identification of Draft Regulatory Guide, DG-1313. This guide is being revised to address new issues identified since the NRC originally issued the guide. As indicated in RG 1.76, “Design Basis Tornado and Tornado Missiles for Nuclear Power Plants” (ADAMS Accession No. ML070360253), tornado wind speeds may not bound hurricane wind speeds for certain portions of the Atlantic and gulf coasts. In this case, the structures, systems, and components should be designed to withstand the effects of the design basis hurricane and hurricane-generated missiles so that they remain functional, as defined in RG 1.221, “Design Basis Hurricane and Hurricane Missiles for Nuclear Power Plants” (ADAMS Accession No. ML110940300). In addition, the title has been updated to better reflect the purpose of the guidance.

II. Additional Information

The NRC published a notice of Availability of DG-1313 in the Federal Register on August 28, 2015 (80 FR 52346), for a 60-day public comment period. The public comment period closed on October 27, 2015. Public comments on DG-1313 and the NRC staff's responses to the public comments are available in ADAMS under Accession No. ML15356A214.

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 methods and procedures that the staff considers acceptable for use in identifying those structures, systems, and components (SSCs) of light water cooled reactors that should be protected from the effects of the worst case extreme winds and wind-generated missiles, so that they remain functional. Although not expressly stated in DG-1313, the regulatory guidance in this regulatory guide is directed at applicants for nuclear power reactor construction permits and operating licenses under part 50 of title 10 of the Code of Federal Regulations (10 CFR), applicants for standard design certifications under subpart B of 10 CFR part 52, and combined licenses under subpart C of part 52.

This 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.” Applicants and potential applicants are not, with certain exceptions, protected by either the Backfit Rule or any issue finality provisions under part 52. Neither the Backfit Rule nor the issue finality provisions under part 52—with certain exclusions discussed below—were intended to apply to every NRC action that substantially changes the expectations of current and future applicants.

The exceptions to the general principle are applicable whenever a combined license applicant references a part 52 license (i.e., an early site permit or a manufacturing license) and/or part 52 regulatory approval (i.e., a design certification rule or design approval). The NRC staff 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 these part 52 licenses and regulatory approvals. If, in the future, the staff seeks to impose a position in this regulatory guide in a manner that does not provide issue finality as described in the applicable issue finality provision, then the NRC staff must address the issue finality criteria in the applicable issue finality provision (10 CFR 52.63 for standard design certification rules, and 10 CFR 52.98 for combined licenses).

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 the inclusion or exclusion of SSCs that must be protected against extreme winds and extreme wind effects. In such cases, backfitting and issue finality will not apply if the NRC determines that the safety review of the licensee-initiated or applicant-initiated change must include reconsideration of the methods and procedures used in identifying those SSCs. Further information on the staff's use of the regulatory guide is contained in the regulatory guide under Section D. Implementation.

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Dated at Rockville, Maryland, this 1st day of July, 2016.

For the Nuclear Regulatory Commission.

Harriet Karagiannis,

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

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[FR Doc. 2016-16553 Filed 7-12-16; 8:45 am]