[Federal Register Volume 74, Number 111 (Thursday, June 11, 2009)]
[Pages 27831-27832]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E9-13708]




Draft NUREG/CR: Issuance, Availability

AGENCY: Nuclear Regulatory Commission.

[[Page 27832]]

ACTION: Notice of Issuance and Availability of Draft NUREG/CR, 
``Diversity Strategies for Nuclear Power Plant Instrumentation and 
Control Systems.''


Regulatory Commission, Washington, DC 20555-0001, telephone: (301) 251-
7451 or e-mail to [email protected].


I. Introduction

    The U.S. Nuclear Regulatory Commission (NRC) is issuing for public 
comment a draft contractor report in the agency's ``NUREG/CR'' series. 
This series was developed to describe and make available to the public 
information such as the results of research conducted on behalf of the 
NRC regarding specific approaches for implementing safety systems in 
accordance with NRC regulations.
    The draft contractor report (NUREG/CR), entitled, ``Diversity 
Strategies for Nuclear Power Plant Instrumentation and Control 
Systems,'' is temporarily identified as ``Diversity NUREG/CR'', which 
should be mentioned in all related correspondence.
    This report presents the technical basis for establishing 
acceptable mitigating strategies that resolve diversity and defense-in-
depth (D3) assessment findings and conform to NRC requirements. The 
research approach employed to establish appropriate diversity 
strategies involves investigation of available documentation on D3 
methods and experience from nuclear power and nonnuclear industries, 
capture of expert knowledge and lessons learned, determination of 
commonalities in diversity approaches, and assessment of the nature of 
common-cause failures (CCFs) and compensating diversity attributes. 
Succinctly, the purpose of the research described in this report was to 
answer the question, ``If diversity is needed in a safety system to 
mitigate the consequences of potential CCFs, how much diversity is 
    The grouping of diversity criteria combinations establishes 
baseline diversity usage and facilitates a systematic organization of 
strategic approaches for coping with CCF vulnerabilities. These 
baseline sets of diversity criteria constitute appropriate CCF 
mitigating strategies for digital safety systems. The strategies 
represent guidance on acceptable diversity usage and can be applied 
directly to ensure that CCF vulnerabilities identified through a D3 
assessment have been adequately resolved. Additionally, a framework has 
been generated for capturing practices regarding diversity usage. A 
metric has been developed for the systematic assessment of the 
comparative effect of proposed diversity strategies on the basis of 
these practices (see Appendix A).

II. Further Information

    The NRC staff is soliciting comments on Diversity NUREG/CR. 
Comments may be accompanied by relevant information or supporting data 
and should mention ``Diversity NUREG/CR'' in the subject line. Comments 
submitted in writing or in electronic form will be made available to 
the public in their entirety through the NRC's Agencywide Documents 
Access and Management System (ADAMS).
    Personal information will not be removed from your comments. You 
may submit comments by any of the following methods:
    1. Mail comments to: Rulemaking Directives Branch, Office of 
Administration, U.S. Nuclear Regulatory Commission, Washington, DC 
    2. E-mail comments to: [email protected].
    3. Fax comments to: Rulemaking and Directives Branch, Office of 
Administration, U.S. Nuclear Regulatory Commission at (301) 492-3446.
    Requests for technical information about Diversity NUREG/CR-xxxx 
may be directed to the NRC contact, Michael E. Waterman at (301) 251-
7541 or e-mail to [email protected].
    Comments would be most helpful if received by July 10, 2009. 
Comments received after that 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 the 
Diversity NUREG/CR currently being developed or improvements in the 
NUREG/CR are encouraged at any time.
    Electronic copies of Diversity NUREG/CR are available in ADAMS 
(http://www.nrc.gov/reading-rm/adams.html), under Accession No. 
    In addition, the draft Diversity NUREG/CR is 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 [email protected].
    NUREG/CRs are not copyrighted, and Commission approval is not 
required to reproduce them.

    Dated at Rockville, Maryland, this 3rd day of June 2009.
    For the Nuclear Regulatory Commission.
Stuart A. Richards,
Deputy Director, Division of Engineering, Office of Nuclear Regulatory 
[FR Doc. E9-13708 Filed 6-10-09; 8:45 am]