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NUREG/CR-XXXX, Development of Quantitative Software Reliability Models for Digital Protection Systems of Nuclear Power Plants Draft Report for Comment

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Nuclear Regulatory Commission.


Announcement of issuance for public comment, availability.


The Nuclear Regulatory Commission has issued for public comment a document entitled: NUREG/CR-XXXX, “Development of Quantitative Software Reliability Models for Digital Protection Systems of Nuclear Power Plants, Draft Report for Comment.”


Please submit comments by July 18, 2011. Comments received after this date will be considered if it is practical to do so, but the NRC staff is able to ensure consideration only for comments received on or before this date.


Please include Docket ID NRC-2011-0109 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, 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 Start Printed Page 28820comments by any one of the following methods:

  • Federal Rulemaking Web Site: Go to and search for documents filed under Docket ID NRC-2011-0109. Address questions about NRC dockets to Carol Gallagher, telephone: 301-492-3668; 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​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 NUREG/CR-XXXX is available electronically under ADAMS Accession Number ML111020087.
  • Federal Rulemaking Web Site: Public comments and supporting materials related to this notice can be found at by searching on Docket ID NRC-2011-0109.
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Alan Kuritzky, Division of Risk Analysis, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001. Telephone: 301-251-7587, e-mail:

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The NRC is conducting research to support development of regulatory guidance for using risk information related to digital systems in the licensing actions of nuclear power plants (NPPs). The objective of this research is to identify and develop methods, analytical tools, and regulatory guidance for (1) including models of digital systems into NPP probabilistic risk assessments (PRAs), and (2) incorporating digital systems in the NRC's risk-informed licensing and oversight activities.

A previous Brookhaven National Laboratory (BNL) technical report, entitled “Review of Quantitative Software Reliability Methods,” BNL-94047-2010 (ADAMS Accession No. ML102240566), documented a review of currently available quantitative software reliability methods (QSRMs) that can be used to quantify software failure rates and probabilities of digital systems at NPPs for use in PRAs and identified a set of desirable characteristics for QSRMs. The current draft report documents a comparison of the previously-identified QSRMs against the set of desirable characteristics. Three candidate QSRMs were identified for further literature review to assess their suitability for estimating demand-failure probabilities of safety-critical protection systems and to formulate an approach for applying each of them to an example system in a case study. The example digital protection system to be used in the case studies is also identified. The actual case studies will be documented in separate reports. Completion of the case studies is expected to provide a much better understanding of the existing capabilities and limitations in treating software failure in digital system reliability models for use in NPP PRAs.

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Dated at Rockville, Maryland, this 10th day of May, 2011.

For the Nuclear Regulatory Commission.

Kevin A. Coyne,

Chief, Probabilistic Risk Assessment Branch, Division of Risk Analysis, Office of Nuclear Regulatory Research.

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[FR Doc. 2011-12200 Filed 5-17-11; 8:45 am]