2015-21305. Protection Against Extreme Wind Events and Missiles for Nuclear Power Plants

AGENCY:

Nuclear Regulatory Commission.

ACTION:

Draft regulatory guide; request for comment.

SUMMARY:

The U.S. Nuclear Regulatory Commission (NRC) is issuing for public comment draft regulatory guide (DG), DG-1313, “Protection Against Extreme Wind Events And Missiles For Nuclear Power Plants.” This proposed guide has been revised to incorporate additional information identified since revision 1 of Regulatory Guide (RG) 1.117 was issued. The proposed revision describes an approach that the staff of the NRC considers acceptable for 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, and remain functional.

DATES:

Submit comments by October 27, 2015. Comments received after this date will be considered if it is practical to do so, but the NRC is able to ensure consideration only for comments received on or before this date. Although a time limit is given, comments and suggestions in connection with items for inclusion in guides currently being developed or improvements in all published guides are encouraged at any time.

ADDRESSES:

You may submit comments by any of the following methods (unless this document describes a different method for submitting comments on a specified subject):

• Federal Rulemaking Web site: Go to http://www.regulations.gov and search for Docket ID NRC-2015-0202. Address questions about NRC dockets to Carol Gallagher; telephone: [phone]; email: [e-mail]. For technical questions, contact the individuals listed in the FOR FURTHER INFORMATION CONTACT section of this document.
• Mail comments to: Cindy Bladey, Office of Administration, Mail Stop: OWFN 12H08, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001.

For additional direction on accessing information and submitting comments, see “Obtaining Information and Submitting Comments” in the SUPPLEMENTARY INFORMATION section of this document.

FOR FURTHER INFORMATION CONTACT:

Gordon Curran, Office of Nuclear Reactor Regulation, telephone: [phone], email: [e-mail] and Stephen Burton, Office of Nuclear Regulatory Research, telephone: [phone] email: [e-mail]. Both are staff of the U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001.

SUPPLEMENTARY INFORMATION:

I. Obtaining Information and Submitting Comments

A. Obtaining Information

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, by any of the following methods:

• Federal Rulemaking Web site: Go to http://www.regulations.gov and search for Docket ID NRC-2015-0202.
• NRC's Agencywide Documents Access and Management System (ADAMS): You may obtain publicly available documents online in the ADAMS Public Documents collection at http://www.nrc.gov/​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 [e-mail]. The ADAMS accession number for each document referenced (if it is available in ADAMS) is provided the first time that a document is mentioned. The DG is electronically available in ADAMS under Accession No. ML14356A107.
• 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.

B. Submitting Comments

Please include Docket ID NRC-2015-0202 in your comment submission. The NRC cautions you not to include identifying or contact information that you do not want to be publicly disclosed in your comment submission. The NRC posts all comment submissions at http://www.regulations.gov as well as enters the comment submissions into ADAMS. The NRC does not routinely edit comment submissions to remove identifying or contact information.

If you are requesting or aggregating comments from other persons for submission to the NRC, then you should inform those persons not to include identifying or contact information that do not want to be publicly disclosed in their comment submission. Your request should state that the NRC does not routinely edit comment submissions to remove such information before making the comment submissions available to the public or entering the comment submissions into ADAMS.

II. Additional Information

The NRC is issuing for public comment a DG in the NRC's “Regulatory Guide” series. This series was developed to describe and make available to the public such information as methods that are acceptable to the NRC staff for implementing specific parts of the NRC's regulations, techniques that the staff uses in evaluating specific problems or postulated accidents, and data that the staff needs in its review of applications for permits and licenses.

The draft regulatory guide, entitled, “Protection Against Extreme Wind Events and Missiles for Nuclear Power Plants,” is temporarily identified by its task number, DG-1313 (ADAMS Accession No. ML14356A107). DG-1313 is proposed revision 2 of RG 1.117. The guide describes an approach that the staff of the NRC considers acceptable for identifying those SSCs of light-water-cooled reactors that should be protected from the effects of the worst case extreme winds and wind-generated missiles, and remain functional.

Nuclear power plants must be designed so that they remain in a safe condition under extreme meteorological events, including those that could result in the most extreme wind events (tornadoes and hurricanes) that could reasonably be predicted to occur at the site. Tornado wind speeds may not bound hurricane wind speeds for certain portions of the Atlantic and gulf coasts at the wind speed frequencies of occurrence considered in revision 1 of RG 1.76, “Design-Basis Tornado and Tornado Missiles for Nuclear Power Plants,” (ADAMS Accession No. ML070360253). The SSCs should be designed to withstand the effects of the design basis hurricane and hurricane generated missiles so that they remain functional. The NRC will also address these extreme conditions on a case-by-case basis.

II. Backfitting and Issue Finality

This draft regulatory guide describes methods and procedures that the staff considers acceptable for use in identifying those 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 (CFR), applicants for standard design certifications under subpart B of part 52, and combined licenses under subpart C of part 52.

This draft regulatory guide, if finalized, would 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 every NRC action which 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 staff does not, at this time, intend to impose the positions represented in the draft regulatory guide (if finalized) 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 (if finalized) in a manner which does not provide issue finality as described in the applicable issue finality provision, then the 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 follow the positions in DG-1313, if finalized, 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 which 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 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 draft regulatory guide, if finalized, is contained in the draft regulatory guide under Section D. Implementation.

Dated at Rockville, Maryland, this 24th day of August, 2015.

For the Nuclear Regulatory Commission.

Thomas H. Boyce,

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