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Draft Regulatory Guide: Denial of Extension of Comment Period

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Information about this document as published in the Federal Register.

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Nuclear Regulatory Commission.


Notice of denial of request to extend the comment period of Draft Regulatory Guide (DG)-1200, “An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities.”

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Mary Drouin, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, telephone: (301) 415-6675 or e-mail to

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I. Introduction

The U.S. Nuclear Regulatory Commission (NRC) issued for public comment DG-1200, which was published in the Federal Register, 73 FR 35170, on June 20, 2008. DG-1200 is proposed Revision 2 of Regulatory Guide 1.200 in the agency's Regulatory Guide Series. This series has been 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.

II. Further Information

The NRC staff requested receipt of comments on DG-1200 by August 25, 2008, (including any implementation schedule) and its associated regulatory analysis or value/impact statement. Comments received after August 25, 2008, would be considered if 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.

III. Request to Extend the Comment Period

Basis for the Request

The NRC received the following extension request:

“This draft regulatory guide revision delineates the NRC's expectations for technical adequacy of PRA [probabilistic risk assessment] information used in support of risk applications and represents a significant expansion over the current Revision by including detailed technical information on fire and external events PRAs. NEI [Nuclear Energy Institute] is coordinating industry comments with the NSSS [nuclear steam supply system] owners group, vendors and licensees to ensure that the comments submitted by industry are of high quality and that Start Printed Page 47984they reflect a consensus industry perspective. However, the comment period provided in the June 20 Federal Register Notice is insufficient given the volume of material and need for a thorough technical review. Extending the comment period would provide the time necessary to fully assess the impact of these proposed changes and arrive at a set of comments that are of value to the NRC staff.”

Response to Request

The request for an extension to the comment period is denied.

The information contained in DG-1200 regarding internal fire and external events has been available to the public prior to the issuance of DG-1200 in June of 2008 for public comment. Therefore, DG-1200 does not “represent a significant expansion over the current Revision [Revision 1] by including detailed technical information on fire and external events PRAs.”

DG-1200 provides high level discussions on what constitutes a technically acceptable Level 1 and Level 2 PRA for internal and external events, which has been in the previous revisions of the guide. Specifically, the information for external events in DG-1200 has not changed since the previous revision. The information for internal fires in DG-1200 was revised from the previous revision; however, the information is high level and was revised to be consistent with the standard (i.e., there was not anything added to the DG-1200 that was new or differing from the standard).

With regard to the internal fire standard (Part 3 of the ASME/ANS RA-S-2008 standard), as documented in DG-1200, the staff has no objections to the majority of the standard's requirements. The staff has continually noted its position during development of the standard and in a formal letter to ASME in November 2007 (ADAMS (​reading-rm/​adams.html), under Accession No. 073030364), and in an April 2008 interoffice letter from M. Cunningham to C. Lui (ADAMS under Accession No. 080880202) which are publicly available.

The staff issued DG-1138 in September 2004 which provided the staff position on Revision 0 of the American Nuclear Society (ANS) external events standard. Revision 1 of the ANS standard (which is Part 4 of the ASME/ANS RA-S-2008 PRA standard) addressed the majority of the staff objections. The staff position in DG-1200, for the objections not addressed in Part 4 of the ASME/ANS RA-S-2008 standard, is unchanged from DG-1138.

Requests for technical information about DG-1200 may be directed to the NRC contact, Mary Drouin at (301) 415-6675 or e-mail to

Electronic copies of DG-1200 are available through the NRC's public Web site under Draft Regulatory Guides in the “Regulatory Guides” collection of the NRC's Electronic Reading Room at​reading-rm/​doc-collections/​. Electronic copies are also available in ADAMS (​reading-rm/​adams.html), under Accession No. ML081200566.

In addition, regulatory guides are available for inspection at the NRC's Public Document Room (PDR), which is located at 11555 Rockville Pike, Rockville, Maryland. The PDR's mailing address is USNRC PDR, Washington, DC 20555-0001. The PDR can also be reached by telephone at (301) 415-4737 or (800) 397-4205, by fax at (301) 415-3548, and by e-mail to

Regulatory guides are not copyrighted, and Commission approval is not required to reproduce them.

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Dated at Rockville, Maryland, this 11th day of August 2008.

For the Nuclear Regulatory Commission.

Stephen C. O'Connor,

Acting Chief, Regulatory Guide Development Branch, Division of Engineering, Office of Nuclear Regulatory Research.

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[FR Doc. E8-18920 Filed 8-14-08; 8:45 am]