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###### Nuclear Regulatory Commission

          - 10 CFR Parts 50 and 52
          - [NRC-2015-0095]
          - RIN 3150-AH42

# 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-1322, “Alternate Risk-Informed Approach for Addressing the Effects of Debris On Post-Accident Long-Term Core Cooling.” This DG proposes new guidance that describes methods and procedures that the NRC staff considers acceptable for complying with a voluntary, risk-informed alternative in a proposed revision of the NRC's regulation governing the design of emergency core cooling systems (ECCS).

# DATES:

Submit comments by July 6, 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-2015-0095. Address questions about NRC dockets to Carol Gallagher; telephone: 301-415-3463; email:                          Carol.Gallagher@nrc.gov.                          For technical questions, contact the individual(s) 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:

                        Steven A. Laur, telephone: 301-415-1465, email:                         *Steven.Laur@nrc.gov,*                         and Steve Burton, telephone: 301-415-7000, email:                         *Stephen.Burton@nrc.gov.*                         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-2015-0095 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-2015-0095.                
    -  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                      pdr.resource@nrc.gov.                      The ADAMS accession number for each document referenced (if it available in ADAMS) is provided the first time that a document is referenced. The DG is electronically available in ADAMS under Accession No. ML15023A025.                
    -  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-2015-0095 in the subject line of your comment submission, in order to ensure that the NRC is able to make your comment submission available to the public in this docket.

                    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 entering 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 they 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 information regarding 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 DG, entitled, “Alternate Risk-Informed Approach for Addressing the Effects of Debris On Post-Accident Long-Term Core Cooling,” is a proposed new guide temporarily identified by its task number, DG-1322. This DG-1322 proposes new guidance that describes methods and procedures that the staff considers acceptable for complying with a voluntary, risk-informed alternative in a proposed revision of the NRC's regulation governing the design of ECCS, section 50.46c of Title 10 of the                           ( print page 21659)    *Code of Federal Regulations*                     (10 CFR), “Emergency core cooling system performance during loss-of-coolant accidents (LOCA),” with respect to the effects of debris during long-term cooling.                

The voluntary alternative was included in the proposed 10 CFR 50.46c rule at the direction of the Commission in the Staff Requirements Memorandum (SRM) regarding SECY-12-0093 “Closure Options for Generic Safety Issue—191, Assessment of Debris Accumulation on Pressurized-Water Reactor Sump Performance,” and in the SRM regarding SECY-12-0034 “Proposed Rulemaking—10 CFR 50.46c: Emergency Core Cooling System Performance During Loss-of-Coolant Accidents (RIN 3150-AH42).” This guide is intended to provide a consistent approach for licensees to use when performing a risk assessment of the complex phenomena associated with debris generation and transport, and the resulting effect on long-term core cooling.

## III. Backfitting and Issue Finality

This DG, if finalized, would not constitute backfitting as defined in § 50.109 (the Backfit Rule), and would not be otherwise inconsistent with the issue finality provisions in 10 CFR part 52, “Licenses, Certifications and Approvals for Nuclear Power Plants.” The NRC published a proposed revision of 10 CFR 50.46c on March 24, 2014 (79 FR 16106). The proposed rule includes the option of allowing an applicant or licensee to address the effects of debris on longterm cooling with respect to ECCS performance requirements in § 50.46c and GDC-35 using a risk-informed approach. The proposed rule would also allow applicants and licensees who select the option to use the same approach in demonstrating compliance with GDC-38 and GDC-41. This DG provides guidance on one possible means for implementing that option. The proposed guidance does not exceed the scope of the proposed rule. Therefore, the backfitting and issue finality discussion for the proposed rule applies to this DG, and further consideration and discussion of backfitting and issue finality for the DG is not necessary.

Dated at Rockville, Maryland, this 13th day of April 2015.

For the Nuclear Regulatory Commission.

Harriet Karagiannis,

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

[FR Doc. 2015-08964 Filed 4-17-15; 8:45 am]

 BILLING CODE 7590-01-P