ML22167A159
| ML22167A159 | |
| Person / Time | |
|---|---|
| Issue date: | 07/01/2022 |
| From: | Bhagwat Jain NRC/NRR/DORL/LPL4 |
| To: | Steve Wyman NRC/NRR/DEX/EEEB |
| Jain B, NRR/DORL/LPL4 | |
| References | |
| Download: ML22167A159 (7) | |
Text
July 1, 2022 MEMORANDUM TO: Stephen Wyman, Acting Chief Electrical Engineering Branch Division of Engineering and External Hazards Office of Nuclear Reactor Regulation FROM: Bhagwat P. Jain, Project Manager /RA/
Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
SUBJECT:
SUMMARY
JUNE 8, 2022 PUBLIC COMMENT GATHERING MEETING ON THE NRC STAFFS PLAN TO EXPAND THE CURRENT COMMON-CAUSE-FAILURE POLICY FOR DIGITAL INSTRUMENTATION AND CONTROLS SYSTEMS TO ALLOW CONSIDERATION OF RISK-INFORMED ALTERNATIVES TO THE STAFF REQUIREMENTS MEMORANDUM TO SECY-93-087 On June 8, 2022, the U.S. Nuclear Regulatory Commission (NRC) staff held a second public comment gathering meeting with external stakeholders to inform and solicit their feedback on the staffs plan to expand the current NRC policy for addressing common-cause-failure (CCF) for digital systems to allow consideration of risk-informed alternatives to the Staff Requirements Memorandum (SRM) to SECY-93-087. The NRC staff made a formal presentation in the meeting. The stakeholders provided their feedback on the staffs plan. The meeting notice and agenda dated May 2, 2022, are available in the Agencywide Documents Access and Management System (ADAMS) at Accession No. ML22122A063. Enclosed is a list of attendees at the meeting.
Meeting Summary During the meeting, the NRC staff from the Office of Nuclear Reactor Regulation (NRR),
Division of Engineering and External Hazards (DEX) and Division of Risk Assessment (DRA) presented the staffs plan (ML22155A001) to develop a SECY paper to allow consideration of risk-informed alternatives to the SRM to SECY-93-087.
The NRC staff provided background of the current digital instrumentation and controls (I&C)
CCF policy, purpose of expanding the current policy, safety concern that the introduction of digital I&C may introduce new failure modes and behaviors, guiding principles for expanding the digital I&C CCF policy, and definition of risk-informed terminology. The staff discussed the proposed expanded CCF policy including the current and the risk-informed paths of the SECY policy paper development milestones and target completion date.
S. Wyman The NRC staff stated that Point 1 does not preclude the use of the risk-informed approach for defense-in-depth and diversity (D3) assessment, and that the risk-informed approach to Point 4 will not likely provide appreciable benefits.
The NRC staff also discussed, in detail, the risk-informed approach to Points 2 and 3 in the risk-informed path.
Overall, the NRC staff delivered the following key messages to stakeholders.
The expanded policy will encompass the current points of SRM-SECY-93-087 (with clarifications) and expand the use of risk-informed approaches.
Any use of risk-informed approaches will be expected to be consistent with the Safety Goal Policy Statement, Probabilistic Risk Assessment (PRA) Policy Statement, and SRM-SECY-98-0144.
The current digital I&C CCF policy will continue to remain a valid option for licensees and applicants.
The staff plans to send the SECY paper to the Commission in 2022.
Upon approval of an expanded policy, the staff will begin updating the implementation guidance in the current Branch Technical Position (BTP) 7-19.
After the NRC staffs presentation, the stakeholders discussed the staffs overall risk-informed path in the proposed expanded CCF policy, and specifically, the risk-informed approach to Points 2 and 4.
The public comment gathering meeting met its objective of engaging the Nuclear Energy Institute (NEI) and other nuclear industry representatives and members of the public in a public discussion on the NRC staffs proposed plan to expand the CCF policy. The stakeholders provided their feedback and comments which are being captured and summarized herein. The meeting was well attended with over 100 participants. Stakeholders thoroughly discussed each step of the staffs proposed risk-informed path, but the bulk of their comments were focused on the risk-informed approach to Points 2 and 4. The staff will consider all stakeholders feedback and inform the SECY paper as appropriate, to clarify its recommendations to the Commission regarding risk-informed approaches for digital I&C CCF in applications for new or amended licenses and design approvals.
A summary of feedback and comments expressed by members of the public are provided below.
Stakeholders Comments on Point 2 The existing policy in SRM-SECY-93-087 specifies that the analysis looks at the Chapter 15 events. The staff did not articulate how the defense-in-depth analysis would be approached in a risk-informed way.
The staff needs to clarify the principles of risk-informed decision making and the scope of the applicability of guidance in Regulatory Guide (RG) 1.174, An Approach for Using
S. Wyman Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis, that rely on a quantitative measurement of risk. The risk cannot be quantified without significant uncertainties. A clarification is needed whether compliance with RG 1.174 is a requirement of the policy.
Stakeholders Comments on Point 4 Clarify what is meant by effectively require in the statement the current regulations effectively require diverse and independent displays and controls.
The staff seems to be creating a broader implementation of diversity than was intended through either the regulations or through the policy statement on its own by adopting together different elements of regulation.
A D3 analysis for each Updated Final Safety Analysis Report (UFSAR) Chapter 15 events is performed to cope with the CCF with or without diverse functions. However, regardless of the D3 analysis, Point 4 requires diverse displays and controls for critical safety functions. This complicates the process and does not really add any value.
Instead, fold this requirement into the criteria in Point 3, instead of having a separate one for Point 4.
Point 4 requires a diverse manual actuation of a critical safety function with the corresponding independent display. If, indeed, Points 3 and 4 are coupled, if you can risk-inform Point 3, why can't you risk-inform Point 4?
Discuss the staffs plans to review the NEI guidance, NEI 20-07, Revision D, Guidance for Addressing Software Common Cause Failure in High Safety-Significant Safety related Digital I&C Systems, with respect to the revision of review guidance upon Commissions approval of the SECY policy paper.
Conclusion At the end of the meeting, NRC management gave closing remarks. No regulatory decisions were made. NEI and other nuclear industry representatives and members of the public provided comments. Public Meeting Feedback forms were not received.
Enclosure:
List of Attendees
LIST OF ATTENDEES JUNE 8, 2022, PUBLIC COMMENT GATHERING MEETING ON NRC STAFFS PLAN TO EXPAND THE CURRENT COMMON-CAUSE-FAILURE POLICY FOR DIGITAL INSTRUMENTATION AND CONTROL SYSTEMS TO ALLOW CONSIDERATION OF RISK-INFORMED ALTERNATIVES TO THE STAFF REQUIREMENTS MEMORANDUM TO SECY 93-087 Microsoft Teams Meeting ATTENDEE ORGANIZATION1 Eric Benner U.S. Nuclear Regulatory Commission (NRC)
Wendell Morton NRC Bhagwat Jain NRC Shilp Vasavada NRC Steve Wyman NRC Kaitlyn Cottrell NRC Mo Sadollah NRC David Rahn NRC Sergiu Basturescu NRC Sunil Weerakkody NRC Bill Roggenbrodt NRC Ismael Garcia NRC Norbert Carte NRC Paul Rebstock NRC Steven Alferink NRC Erick Martinez NRC Christopher Cook NRC Manuel Ruiz Diaz NRC Sheldon Clark NRC Duane White NRC Joseph Ashcraft NRC Richard Stattel NRC Samir Darbali NRC Jason Drake NRC Roy Hardin NRC David Desaulniers NRC Hang Vu NRC Ian Jung NRC Jack Zhao NRC Steve Ruffin NRC Michael Marshall NRC 1 Unknown organization indicates that the participants affiliation was not provided by the issuance of this meeting summary.
Enclosure
ATTENDEE ORGANIZATION1 Derek Halverson NRC Khoi Nguyen NRC John McKirgan NRC Andrea Kock NRC Kamishan Martin NRC Mauricio Gutierrez NRC Michael Waters NRC Sushil Birla NRC Christina Antonescu NRC Jennifer Dixon-Herrity NRC Charles Peabody NRC Robert Krsek NRC Jana Bergman Curtiss-Wright Svetlana Lawrence Idaho National Laboratory George Raymond INPO Alan Campbell Nuclear Energy Institute Warren Odess-Gillett Westinghouse Electric Company LLC Rachelle Johnson Constellation Energy Generation, LLC (Constellation)
Nathan Faith Constellation Philip Tarpinian Constellation Zachary Ballert Constellation (Contractor)
Mark Dirado Constellation Raymond Herb Southern Company David Herrell MPR Richard Supler Enercon Services, Inc Mark Burzynski Sunport Robert Chenkovich Dominion Energy Brian Haynes Framatome -ICSP Ron Jarrett Framatome Anil Julka NextEra Energy, Inc.
Mack Jarrett NextEra Energy, Inc Mike Wiwel PSEG Nuclear LLC Rob Burg EPM Fernando Ferrante Electric Power Research Institute Neil Archambo Unknown Gary Johnson Unknown Bob Hirmanpour Unknown Maribel Valdez Unknown Steven Erickson Unknown Eric Thornsbury Unknown Arthur Holtz Unknown Tom Gurdziel Unknown Fred Madden Unknown Ben Burnett Unknown Roger Wyatt Unknown Erin Wisler Unknown Omran Samadi Unknown Shawn Gibby Unknown
ATTENDEE ORGANIZATION1 John Weglian Unknown Mike Montecalvo Unknown Brian Kwiatkowski Unknown Jerry Mauck Unknown Chris Lauderbaugh Unknown Ted Quinn Unknown
ML22167A159 *by email OFFICE NRR/DORL/LPL4/PM* NRR/DORL/LPL4/LA* NRR/DEX/EICB/BC*
NAME BJain PBlechman MWaters DATE 6/15/2022 7/1/2022 6/30/2022 OFFICE NRR/DEX/ELTB/BC (A)* NRR/DORL/LPL4/PM*
NAME SWyman BJain DATE 6/30/2022 7/1/2022