[Federal Register Volume 85, Number 9 (Tuesday, January 14, 2020)]
[Notices]
[Pages 2152-2153]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-00350]



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NUCLEAR REGULATORY COMMISSION

[NRC-2019-0253]


Proposed Revision to Standard Review Plan Branch Technical 
Position 7-19 Guidance for Evaluation of Potential Common Cause Failure 
Due to Latent Software Defects in Digital Instrumentation and Control 
Systems

AGENCY: Nuclear Regulatory Commission.

ACTION: Standard review plan; draft section revision; request for 
comment.

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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is soliciting 
public comment on draft NUREG-0800, ``Standard Review Plan for the 
Review of Safety Analysis Reports for Nuclear Power Plants: LWR 
Edition,'' Branch Technical Position (BTP) 7-19, ``Guidance for 
Evaluation of Potential Common Cause Failure Due to Latent Software 
Defects in Digital Instrumentation and Control Systems.''

DATES: Comments must be filed no later than March 16, 2020. Comments 
received after this date will be considered, if it is practical to do 
so, but the Commission is able to ensure consideration only for 
comments received on or before this date.

ADDRESSES: You may submit comments by any of the following methods:
     Federal Rulemaking Website: Go to https://www.regulations.gov and search for Docket ID NRC-2019-0253. Address 
questions about NRC dockets IDs in Regulations.gov to Jennifer Borges; 
telephone: 301-287-9127; email: [email protected]. For technical 
questions, contact the individual listed in the FOR FURTHER INFORMATION 
CONTACT section of this document.
     Mail comments to: Office of Administration, Mail Stop: 
TWFN-7-A60M, U.S. Nuclear Regulatory Commission, Washington, DC 20555-
0001, ATTN: Program Management, Announcements and Editing Staff.
    For additional direction on obtaining information and submitting 
comments, see ``Obtaining Information and Submitting Comments'' in the 
SUPPLEMENTARY INFORMATION section of this document.

FOR FURTHER INFORMATION CONTACT: Mark Notich, Office of New Reactors, 
U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001; 
telephone: 301-415-3053; email: [email protected].

SUPPLEMENTARY INFORMATION: 

I. Obtaining Information and Submitting Comments

A. Obtaining Information

    Please refer to Docket ID NRC-2019-0253 when contacting the NRC 
about the availability of information for this action. You may obtain 
publicly-available information related to this action by any of the 
following methods:
     Federal Rulemaking Website: Go to https://www.regulations.gov and search for Docket ID NRC-2019-0253.
     NRC's Agencywide Documents Access and Management System 
(ADAMS): You may obtain publicly-available documents online in the 
ADAMS Public Documents collection at https://www.nrc.gov/reading-rm/adams.html. To begin the search, 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 [email protected]. The draft of NUREG-0800, ``Standard 
Review Plan for the Review of Safety Analysis Reports for Nuclear Power 
Plants: LWR Edition,'' BTP 7-19, ``Guidance for Evaluation of Potential 
Common Cause Failure in Digital Instrumentation and Control Systems'' 
is available in ADAMS under Accession No. ML19256B502.
     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-2019-0253 in your comment submission.
    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 will post all comment submissions at 
https://www.regulations.gov as well as enter 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 into ADAMS.

II. Further Information

    The NRC seeks public comment on the proposed draft revision of BTP 
7-19. This BTP has been developed to assist NRC staff in the review of 
licensing applications involving digital technology that may be subject 
to common cause failures. Common cause failures have been identified as 
a type of hazard that digital instrumentation and control systems could 
be susceptible to due to the integration capabilities provided by the 
technology and due to its inherent complexity compared to analog 
technologies.
    The proposed revision to BTP 7-19 provides a graded approach for 
addressing common cause failures due to latent defects based on the 
safety classification and safety significance of the proposed digital 
I&C structures, systems, and components (SSCs). For safety-related I&C 
SSCs that are safety significant, this proposed revision provides 
additional guidance for performing a defense-in-depth and diversity 
assessment. The guidance includes clarifications on acceptable means to 
eliminate common cause failures from further consideration and 
acceptable diverse means that can be used to perform the same or 
different function than the safety function disabled by the postulated 
common cause failures. For safety-related digital I&C SSCs that are not 
safety significant or digital I&C SSCs that are not safety-related but 
are safety significant, this proposed revision provides criteria on the 
performance of a qualitative assessment. This proposed revision also 
clarifies the criteria for performing a spurious operation assessment 
for digital I&C SSCs. The current version of BTP 7-19 can be found in 
ADAMS under Accession No. ML16019A344. The proposed Revision 8 to BTP 
7-19 can be found in ADAMS under Accession No. ML19256B502.
    The NRC staff presented proposed Revision 8 to BTP 7-19 to the 
Advisory Committee for Reactor Safeguards (ACRS) Subcommittee on 
November 21, 2019. Based on feedback received from ACRS Subcommittee 
members during the meeting, the NRC staff modified proposed Revision 8 
to BTP 7-19 to enhance the structure of the BTP and to clarify the 
process descriptions for evaluating common-cause failure hazards. These 
modifications did not result in changes to the technical content of 
this BTP. Additional structural modifications and technical content 
clarifications may be necessary to improve this BTP. Therefore, the NRC 
staff is public comments to facilitate enhancing both the structure and 
the

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technical content of this proposed BTP 7-19 revision.
    Following NRC staff evaluation of public comments, the NRC intends 
to finalize BTP 7-19 Revision 8 in ADAMS and post it on the NRC's 
public website at https://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr0800/. The SRP is guidance for the NRC staff. The SRP is 
not a substitute for the NRC regulations, and compliance with the SRP 
is not required.

III. Backfitting, Issue Finality, and Forward Fitting Discussion

    Chapter 7 of the SRP provides guidance to the staff for reviewing 
information on instrumentation and controls in licensing applications. 
Issuance of this draft BTP, if finalized, would not constitute 
backfitting as defined in title 10 of the Code of Federal Regulations 
(10 CFR) 50.109 (the Backfit Rule) and as described in NRC Management 
Directive 8.4, ``Management of Backfitting, Forward Fitting, Issue 
Finality, and Information Requests;'' would not affect the issue 
finality of an approval under 10 CFR part 52; and would not constitute 
forward fitting as that term is defined and described in Management 
Directive 8.4. The staff's position is based upon the following 
considerations.
    1. The draft BTP, if finalized, would not constitute backfitting or 
forward fitting or affect issue finality, inasmuch as the BTP would be 
internal guidance to NRC staff.
    The BTP provides guidance to the staff on how to review an 
application for NRC regulatory approval in the form of licensing. 
Changes in internal staff guidance, without further NRC action, are not 
matters that meet the definition of backfitting or forward fitting or 
affect the issue finality of a part 52 approval.
    2. Current or future applicants are not--with limited exceptions 
not applicable here--within the scope of the backfitting and issue 
finality regulations and forward fitting policy.
    Applicants are not, with certain exceptions, covered by either the 
Backfit Rule or any issue finality provisions under 10 CFR part 52. 
This is because neither the Backfit Rule nor the issue finality 
provisions under 10 CFR part 52--with certain exclusions discussed 
below--were intended to apply to every NRC action which substantially 
changes the expectations of current and future applicants.
    The exceptions to the general principle are applicable whenever an 
applicant references a 10 CFR part 52 license (e.g., an early site 
permit) and/or NRC regulatory approval (e.g., a design certification 
rule) with specified issue finality provisions or a construction permit 
under 10 CFR part 50. The staff does not, at this time, intend to 
impose the positions represented in the draft BTP (if finalized) in a 
manner that would constitute backfitting or affect the issue finality 
of a part 52 approval. If, in the future, the staff seeks to impose a 
position in the draft BTP (if finalized) in a manner that constitutes 
backfitting or does not provide issue finality as described in the 
applicable issue finality provision, then the staff would need to 
address the Backfit Rule or the criteria for avoiding issue finality as 
described in the applicable issue finality provision.
    The staff does not, at this time, intend to impose the positions 
represented in the draft BTP (if finalized) in a manner that would 
constitute forward fitting. If, in the future, the staff seeks to 
impose a position in the draft BTP (if finalized) in a manner that 
constitutes forward fitting, then the staff would need to address the 
forward fitting criteria in Management Directive 8.4.

    Dated at Rockville, Maryland, this 8th day of January, 2020.

    For the Nuclear Regulatory Commission.
Dennis C. Morey,
Chief, Licensing Projects Branch, Division of Operating Reactor 
Licensing, Office of Nuclear Reactor Regulation.
[FR Doc. 2020-00350 Filed 1-13-20; 8:45 am]
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