ML18340A124
| ML18340A124 | |
| Person / Time | |
|---|---|
| Issue date: | 12/20/2018 |
| From: | Chris Miller Division of Inspection and Regional Support |
| To: | Geier S Nuclear Energy Institute |
| Govan T | |
| References | |
| NEI 96-07 | |
| Download: ML18340A124 (5) | |
Text
December 20, 2018 Mr. Steve Geier Director, Engineering and Risk Generation and Suppliers Division Nuclear Energy Institute 1201 F Street, NW, Suite 1100 Washington, DC 20004
SUBJECT:
NRC STAFF COMMENTS ON NUCLEAR ENERGY INSTITUTE 96-07, APPENDIX D, SUPPLEMENTAL GUIDANCE FOR APPLICATION OF 10 CFR 50.59 TO DIGITAL MODIFICATIONS
Dear Mr. Geier:
On April 4, 2016, the U.S. Nuclear Regulatory Commission (NRC) staff received a letter from the Nuclear Energy Institute (NEI) requesting comments on draft Revision 0 of NEI 96-07, Appendix D, Supplemental Guidance for Application of 10 CFR 50.59 to Digital Modifications (Agencywide Documents Access and Management System (ADAMS) Accession No. ML16126A197). In this request, NEI stated that NEI 96-07, Appendix D, is intended to supplement existing guidance in NEI 96-07, Guidelines for 10 CFR 50.59 Evaluations, Revision 1, as endorsed in Regulatory Guide 1.187, Guidance for Implementation of 10 CFR 50.59, Changes, Tests, and Experiments, issued November 2000. NEI further stated that the guidance in NEI 96-07, Appendix D, is intended strictly for the application of the process in Title 10 of the Code of Federal Regulations (10 CFR) 50.59 and that the examples in the guidance would provide enough detail to understand the types of digital modifications under consideration by licensees.
Background
The objectives of 10 CFR 50.59 are to ensure that licensees do the following:
- Evaluate proposed changes to their facilities for their effects on the licensing basis of the plant, as described in their updated final safety analysis reports (UFSARs).
- Obtain prior NRC approval for changes that meet specified criteria as having a potential impact upon the basis for issuance of the operating license.
By letter dated November 5, 2013 (ADAMS Accession No. ML13298A787), the NRC staff summarized its concerns with regard to licensee implementation of the current guidance in NEI 01-01, Guideline on Licensing Digital Upgrades: EPRI [Electric Power Research Institute]
TR [Technical Report]-102348, Revision 1, NEI 01-01: A Revision of EPRI TR-102348 to Reflect Changes to the 10 CFR 50.59 Rule. In the November 2013 letter, the staff indicated
S. Geier that the NEI 01-01 guidance for 10 CFR 50.59 screening and evaluation of digital instrumentation and control (I&C) systems was inadequate and contributed to several licensees having improperly performed 10 CFR 50.59 evaluations for modifications of I&C systems using digital technologies. The NRC staff held several public meetings with industry representatives on this subject to provide feedback on how guidance should be improved.
In response to the NRC staffs concerns, NEI formed a working group to, among other things, update its guidance for implementing digital I&C modifications under 10 CFR 50.59. Because of numerous interactions among NEI, the NRC, and other stakeholders, the NRC staff expanded its efforts under a broader initiative to modernize its digital I&C regulatory infrastructure. The NRC staff submitted the Integrated Action Plan, including modernization plans for specific areas that the Commission approved in October 2016 (ADAMS Accession No. ML16097A182).
Modernization Plan 2 of the Integrated Action Plan addresses the need for clarity on 10 CFR 50.59 screenings and evaluations of proposed digital I&C plant modifications.
Since NEIs original April 2016 request for comments on NEI 96-07, Appendix D, the NRC staff has engaged in numerous public discussions with NEI on specific areas for which the guidance on 10 CFR 50.59 for digital modifications should be improved. In December 2017, NEI and the NRC staff mutually agreed to place the review of NEI 96-07, Appendix D, on hold to dedicate resources to the issuance of a Supplement to Regulatory Issue Summary 2002-22, Use of EPRI/NEI Joint Task Force Report, Guideline on Licensing Digital Upgrades: EPRI TR-102348, Revision 1, NEI 01-01: A Revision of EPRI TR-102348 to Reflect Changes to the 10 CFR 50.59 Rule, dated November 25, 2002, as a means to address the implementation of 10 CFR 50.59 from a technical perspective (i.e., using qualitative assessments). Since reengaging with NEI on NEI 96-07, Appendix D, in June 2018, the NRC staff has provided NEI with a set of extensive staff comments and insights to inform NEIs development of NEI 96-07, Appendix D, which the NRC staff communicated to NEI during a public meeting in August 2018 (ADAMS Accession No. ML18282A216).
The NRC staff met with NEI at three additional public meetings in September 2018 (ADAMS Accession No. ML18283B628), October 2018 (ADAMS Accession No. ML18298A295), and November 2018 (ADAMS Accession No. ML18333A057). At each meeting, the NRC staff provided additional clarification to NEI as it revised the NEI 96-07, Appendix D, guidance document. Following these interactions, NEI submitted its proposed final version of NEI 96-07, Appendix D, on November 30, 2018 (ADAMS Accession No. ML18338A389) for NRC staff endorsement, with the understanding that the NRC comments that were not addressed would be further reviewed and dispositioned during this process. If the NRC endorses NEI 96-07, Appendix D, the NRC may take exception to certain statements in NEI 96-07, Appendix D, including the NRC comments with which NEI did not agree or has not yet addressed.
NRC Comments on NEI 96-07, Appendix D NEI submitted NEI 96-07, Appendix D, to the NRC staff as a means of addressing 10 CFR 50.59 challenges pertaining to digital technology implementation as a result of the unique challenges posed (e.g., introduction of software). As such, NEI 96-07, Appendix D, describes approaches intended to address challenges concerning digital technology implementation under 10 CFR 50.59. Because NEI 96-07, Appendix D, specifically addresses one specific discipline (digital I&C), the NRC staff considers NEI 96-07, Appendix D, to be applicable to digital modifications only and not generically applicable to the 10 CFR 50.59 process.
S. Geier NEI 96-07, Appendix D, Section 4.3.6, provides guidance on 10 CFR 50.59(c)(2)(vi). If a proposed change meets the criterion in 10 CFR 50.59(c)(2)(vi), namely, it would create a possibility for a malfunction of a [structure, system, or component (SSC)] important to safety with a different result than any previously evaluated in the [UFSAR], then the licensee must obtain a license amendment prior to implementing that change. In regard to 10 CFR 50.59(c)(2)(vi), Section 4.3.6 of NEI 96-07, Appendix D, indicates that a different result is related only to the safety analysis for the facility as a whole but not to the safety analysis of the individual structures, systems, and components (SSCs) that are being modified.
The NRC staff disagrees with the above understanding of 10 CFR 50.59(c)(2)(vi) stated in Section 4.3.6 of NEI 96-07, Appendix D, for the following reasons. NEI 96-07, Revision 1, defines safety analysis as including supporting USFAR analyses that demonstrate that SSC design functions will be accomplished as credited in the accident analysis. NEI 96-07, Revision 1, also states that malfunctions of SSCs are postulated as potential single failures at the level of the SSC being modified. Therefore, the NRC staffs position is that Section 4.3.6 of NEI 96-07, Appendix D, should determine the SSC malfunction impact instead of the safety analysis result impact on the facility as a whole. Section 4.3.6 of NEI 96-07, Appendix D, generally focuses on the safety analysis result impact rather than the malfunction result impact, which is contrary to the NRC staffs interpretation of the guidance in NEI 96-07 and of 10 CFR 50.59. This comment carries through much of Section 4.3.6 of NEI 96-07, Appendix D, including the examples.
The NRC staff will consider the issues identified by its previous comments as part of the staff formal review of NEI 96-07, Appendix D, for possible endorsement (ADAMS Accession No. ML18330A126). The NRC staff may identify additional unresolved matters during that review. If any matter remains unresolved at the end of the staff review of NEI 96-07, Appendix D, including the guidance in Sections 4.3.6 on 10 CFR 50.59(c)(2)(vi) discussed above, the NRC staff will take exception to it (i.e., will include relevant conditions in the possible endorsement of NEI 96-07, Appendix D).
NRC Endorsement Process The NRC endorsement process will include final NRC staff review of NEI 96-07, Appendix D, the development of a draft regulatory guide, a public comment period and comment resolution, and the development of a final regulatory guide. The NRC staff anticipates that, because of the extensive level of engagement between the NRC staff and NEI during the development of NEI 96-07, Appendix D, the staff could finish its review and, if the staff decides to endorse NEI 96-07, Appendix D, revise Regulatory Guide 1.187 in approximately 6 months. This estimated 6-month period does not account for situations beyond the NRC staffs control (e.g., a request for additional time during the public comment period for the draft regulatory guide, Office of Management and Budget clearance), nor does it allow for further NEI revision of the guidance.
Nonetheless, the NRC staff remains willing to accommodate NEI and extend the schedule should NEI seek to revise NEI 96-07, Appendix D, to address the staff concerns or otherwise improve the guidance. The assigned NRC project manager will inform NEI of the status of the staffs review of NEI 96-07, Appendix D.
S. Geier If you have any concerns or questions, please contact Ms. Tekia Govan, Project Manager, at (301) 415-6197, or through e-mail to Tekia.Govan@nrc.gov.
Sincerely,
/ra/ (Jeremy R. Groom for)
Christopher G. Miller, Director Division of Inspection and Regional Support Office of Reactor Regulation cc: Kati Austgen, NEI
ML18340A124 *via email OFFICE NRR/DIRS/IRGB/PM NRR/DIRS/IRGB/TL NRR/DIRS/IRGB/PM RES/DE/ICEEB/TR NAME TGovan PMcKenna* DBeaulieu* EMartinez*
DATE 12/06/2018 12/06/2018 12/06/2018 12/06/2018 OFFICE NRR/DE/EICB/TR NRR/DE/EICA/TR QTE* NRR/DE/EICB/BC NAME NCarte NONCONCUR* WMorton* w/comments MWaters*w/comments DATE 12/6/2018 12/11/2018 12/10/2018 12/17/2018 OFFICE NRR/DE/EICA/BC NRR/DIRS/IRGB/PM OGC NRO/DE NAME NSalgado* BPham* RWeisman/SClark* BCaldwell*
DATE 12/19/2018 12/19/2018 12/18/2018 12/19/2018 OFFICE RES/DE NRR/DE NRR/DIRS/IRGB/LA NRR/DIRS NAME BThomas* EBenner* ELee* CMiller(JGroom for)
DATE 12/20/2018 12/19/2018 12/19/2018 12/20/2018