2011-10712. Solicitation for Public Comment on Potential Alternatives To Resolve Generic Safety Issue 191, Pressurized Water Reactor Sump Performance

AGENCY:

Nuclear Regulatory Commission (NRC).

ACTION:

Solicitation of public comment.

SUMMARY:

The NRC is seeking public comment on potential alternatives for risk informing the path forward to resolve Generic Safety Issue (GSI) 191, Pressurized Water Reactor (PWR) Sump Performance.

DATES:

Submit comments by July 5, 2011.

ADDRESSES:

Please include Docket ID NRC-2011-0090 in the subject line of your comments. Comments submitted in writing or in electronic form will be posted on the NRC Web site and on the Federal rulemaking Web site, http://www.regulations.gov. Because your comments will not be edited to remove any identifying or contact information, the NRC cautions you against including any information in your submission that you do not want to be publicly disclosed.

The NRC requests that any party soliciting or aggregating comments received from other persons for submission to the NRC inform those persons that the NRC will not edit their comments to remove any identifying or contact information, and therefore, they should not include any information in their comments that they do not want publicly disclosed. You may submit comments by any one of the following methods:

• Federal Rulemaking Web Site: Go to http://www.regulations.gov and search for documents filed under Docket ID NRC-2011-0090. Address questions about NRC dockets to Carol Gallagher, telephone: [phone]; e-mail: [e-mail].
• Mail comments to: Cindy Bladey, Chief, Rules, Announcements, and Directives Branch (RADB), Office of Administration, Mail Stop: TWB-05-B01M, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001.
• Fax comments to: RADB at 301-492-3446.

You can access publicly available documents related to this notice using the following methods:

• NRC's Public Document Room (PDR): The public may examine and have copied, for a fee, publicly available documents at the NRC's PDR, O1-F21, One White Flint North, 11555 Rockville Pike, Rockville, Maryland 20852.
• NRC's Agencywide Documents Access and Management System (ADAMS): Publicly available documents created or received at the NRC are available online in the NRC Library at http://www.nrc.gov/​reading-rm/​adams.html. From this page, the public can gain entry into ADAMS, which provides text and image files of the NRC's public documents. If you do not have access to ADAMS or if there are problems in accessing the documents located in ADAMS, contact the NRC's PDR reference staff at 1-800-397-4209, 301-415-4737, or by e-mail to [e-mail].
• Federal Rulemaking Web Site: Public comments and supporting materials related to this notice can be found at http://www.regulations.gov by searching on Docket ID NRC-2011-0090.

FOR FURTHER INFORMATION CONTACT:

Mr. Stewart Bailey, Chief of Safety Issue Resolution Branch, telephone [phone], e-mail: [e-mail], or in writing at the Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001.

Background

The NRC identified a potential susceptibility of PWR emergency core cooling system (ECCS) recirculation sump screens and associated flow paths to debris blockage during design basis accidents that require recirculation operation. As a result, all operating PWR licensees were requested in Generic Letter (GL) 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors, to perform a mechanistic evaluation of the recirculation functions and, as appropriate, to take additional actions (e.g., plant modifications) to ensure system functionality.

An overview of licensee and NRC staff actions to address GSI-191 can be found in Policy Issue Notation Vote Paper (SECY-10-0113) which presented to the Commission the regulatory path forward options for closure. In a Staff Requirement Memorandum (SRM) dated December 23, 2010, the Commission directed the staff, in part, to explore alternative paths forward for resolving GSI-191.

Discussion

While GSI-191 has not yet been fully resolved, the NRC believes that measures taken thus far in response to the sump-clogging issue have contributed greatly to the safety of US nuclear power plants. Given the vastly enlarged advanced strainers installed, compensatory measures already taken, and the low probability of challenging pipe breaks, adequate levels of safety and defense-in-depth are currently being maintained. In light of these factors, the Commission directed that the staff should take the time needed to consider all options to a risk-informed, safety conscious resolution to GSI-191.

The SRM to SECY-10-0113 stated that the staff should employ innovation and creativity in fully exploring the policy and technical implications of all available alternatives for risk informing the path forward. These alternatives were to include, but not be limited to, how proposed rule for Title 10 of the Code of Federal Regulations, Section 50.46a might impact this issue, and how the application of a “no-transition-break-size” approach might work. SECY-10-0113 is publically available in the Agencywide Documents Access and Management System (ADAMS) under accession No. ML101820296. The SRM to SECY-10-0113 is also publically available in ADAMS under accession No. ML103570354. Stakeholders and interested parties are encouraged to introduce other options, issues, and information for the NRC's consideration.

In an effort to facilitate public involvement, the staff previously solicited public input during the 2011 NRC Regulatory Information Conference (RIC), held in Rockville, MD. During the RIC, GSI-191 was the subject of one of the RIC technical sessions. Information concerning the 2011 RIC is available at http://www.nrc.gov/​public-involve/​conference-symposia/​ric. The GSI-191 technical session agenda and links to all presentation documents can be found at https://ric.nrcgateway.gov/​docs/​abstracts/​SessionAbstract_​7.htm.

Dated at Rockville, Maryland, this 14th day of April 2011.

For the Nuclear Regulatory Commission.

Sher Bahadur,

Acting Director, Division of Safety Systems, Office of Nuclear Reactor Regulation.