ML22054A002
| ML22054A002 | |
| Person / Time | |
|---|---|
| Issue date: | 03/14/2022 |
| From: | Bhagwat Jain NRC/NRR/DORL/LPL4 |
| To: | Jeanne Johnston NRC/NRR/DEX/ELTB |
| Jain B | |
| References | |
| SECY 93-087 | |
| Download: ML22054A002 (7) | |
Text
March 14, 2022 MEMORANDUM TO: Jeanne A. Johnston, Chief Long Term Operations and Modernization Branch Division of Engineering and External Hazards Office of Nuclear Reactor Regulation FROM: Bhagwat Jain /RA/
Plant Licensing Branch IV Division Operating Reactor Licensing Office of Nuclear Reactor Regulation
SUBJECT:
SUMMARY
OF THE PUBLIC COMMENT GATHERING MEETING ON 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, HELD ON FEBRUARY 15, 2022 On February 15, 2022, the U.S. Nuclear Regulatory Commission (NRC) staff held a first 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. NRC staff, Nuclear Energy Institute (NEI), and Idaho National Laboratory (INL) made formal presentations in the meeting. The stakeholders provided their feedback on the staffs plan. The meeting notice and agenda are available in ADAMS at Accession No. ML22043A002. 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 (ADAMS Accession No. ML22042A052) to develop a SECY paper to allow consideration of risk-informed alternatives to the SRM to SECY-93-087. The 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, definition of risk-informed terminology, and SECY policy paper development milestones and target completion date. After the staffs presentation, the stakeholders discussed the staffs plan and provided feedback.
J. Johnston NEI presented a summary of its CCF policy provided earlier in its report NEI 20-07, Draft D, which describes a risk-informed alternative to address digital I&C CCF. The NEI presentation also included its proposed positions on SRM to SECY-93-087. The NEI presentation is available in ADAMS at Accession No. ML22042A009.
INL presented its ongoing research on CCF analysis, safety evaluation, and design optimization of safety-related digital I&C systems. INL discussed a framework of CCF analysis for integrated risk assessment for digital I&C systems with the following goals.
Develop an advanced risk assessment framework to support industrys transition from analog to digital technologies for safety-related I&C systems.
Develop an integrated platform that includes all aspects of a typical risk assessment: hazard analysis, reliability analysis, and consequence analysis.
Provide a systematic, verifiable and reproducible approach based on technically-sound methodologies.
The INL presentation is available in ADAMS at Accession No. ML22041A009.
The public comment gathering meeting met its objective of engaging NEI and other nuclear industry representatives and members of the public in a public discussion on the staffs proposed plan to expand the CCF policy. The stakeholders provided their feedback and comments that are captured and summarized herein. The meeting was well attended with over 100 participants. The main comments were geared towards the SECY paper development milestones and schedule, risk considerations, software reliability, consequence calculations, revision to BTP 7-19, and to hold more public engagement on this topic in the future.
One stakeholder requested NRC staff to interact with the Advisory Committee on Reactor Safeguards (ACRS) in the development of the SECY paper and use their knowledge and experience early in the process. One stakeholder had provided written comments before the virtual meeting (ADAMS Accession No. ML22060A186) and after the virtual meeting (ADAMS Accession No. ML22060A185) due to technical difficulties during the virtual meeting. A summary of feedback and comments expressed by members of the public is provided below.
What is the risk of concern to the NRC from CCF? How much risk is the NRC now accepting?
Define common mode failure and compare/contrast it to common cause failure. Is there a limiting boundary for risk-informed work such that the maximum amount of risk found to be acceptable is clearly identified? Risk-based actions are allowable up to what clearly identified amount of risk?
How would the NRC staff address complexity in designs to reduce the likelihood of design defects and how would you put some bounds on complexity so you can input them into the risk model?
Will the NRC staff revise Branch Technical Position (BTP) 7-19? If yes, will it be concurrent with the development of the SECY?
The NRC staff did not provide explanation of how low probability - high consequence events are to be handled.
J. Johnston The NRC staff should be looking at how aviation and process industries have addressed the CCF issue. Often the cause of sever accident is error in specification of I&C design requirement and their implementation.
The NRC staff should use bounds on software reliability in probabilistic risk model to screen CCF in or out.
It is not necessary to have reliability goals or reliability studies if we have redundancy and defense-in-depth already.
The NRC staff must provide a specific value of reliability below which the occurrence of Digital I & C Common Cause Failure is acceptable.
The NRC staff, in one of the accepted methods to address CCF in digital I&C -
Consequence Calculations - seem to be accepting risk since dose increase at the site boundary means reactor core meltdown. The staff identified consequence calculation as a possible tool to understand how the offsite dose consequence of an event could affect the health and safety of the public. Not all postulated events necessarily lead to a core meltdown. How frequently will a loss of safety function always lead to core damage? As written, the consequence calculation method did not do what needs to be done to directly address CCF.
The NRC function on consensus basis. This method does not work when you are in a hurry. The NRC need one person in-charge and that person must be held accountable for necessary decisions and progress or must be replaced.
How is the NRC staff going to use the wealth of experience and knowledge available on the ACRS?
The NRC staff should continue with the public meetings.
Conclusion At the end of the meeting, NRC and industry 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:
As stated
LIST OF ATTENDEES FEBRUARY 15, 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 Jeanne Johnston NRC Tony Nakanishi NRC Muzammil Siddiqui 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 Ming Li NRC Christopher Cook NRC Ed Miller NRC Sheldon Clark NRC Dinesh Taneja NRC Ramon Gascot Lozada NRC Richard Stattel NRC Samir Darbali NRC Duane Hardesty NRC Roy Hardin NRC Neil Sheehan NRC Anthony Rossi NRC Shakur Walker NRC Jack Zhao NRC Steve Ruffin NRC Michael Marshall NRC Stacey Rosenberg NRC Calvin Cheung NRC Enclosure
ATTENDEE ORGANIZATION1 Jorge Cintron-Riveria NRC Andrea KocK NRC Jo Jacobs NRC Mauricio Gutierrez NRC Michael Waters NRC Sushil Birla NRC Christina Antonescu NRC Bao Han Idaho National Laboratory (INL)
Prescott Steven INL Otani Courtney INL Shorthill Tate INL Lawrence Svetlana INL Cathy Barnard INL Bruce Halbert INL Jana Bergman Curtiss-Wright David Jaroshda Westinghouse Electric Company LLC (Westinghouse)
Andrew Detara Westinghouse Warren Odess-Gillett Westinghouse Heather Detar Westinghouse Maria Assard Westinghouse Alan Campbell Nuclear Energy Institute (NEI)
Thomas Basso NEI Tony Brown NEI Frances Pimental NEI Francis Mascitelli Constellation Energy Generation, LLC (Constellation)
Nathan Faith Constellation James Landale Constellation Suzanne Loyd Constellation Christian Williams Constellation John Connelly Constellation Zachary Rhoads Constellation Philip Tarpinian Constellation Mark Samselski Constellation Zachary Ballert Constellation (Contractor)
David Hooten Sargent & Lundy Richard Paese Sargent & Lundy Raymond Herb Southern Company David Herrell MPR Danny Duong MPR Marty Flynn Entergy Operations, Inc. (Entergy)
Steve Freel Entergy Richard Supler Enercon Services, Inc.
Jason Gasque Tennessee Valley Authority Mark Burzynski Sunport Robert Chenkovich Dominion Energy Michael Pollard Dominion Energy Paul McCutchan Dominion Energy Lisa Gerken Framatome
ATTENDEE ORGANIZATION1 Ron Jarrett Framatome Wesley Ferwin NextEra Energy, Inc.
Fernando Ferrante Electric Power Research Institute Vince Gilbert Model Performance David Herrin U.S. Department of Energy (DOE)
William Walsh DOE Mike Wiwel PSEG Nuclear LLC Gary DeMoss PSEG Nuclear LLC John Conly Certrec Christopher Deloglos Symple Solutions Inc Rob Burg EPM Steve Vaughn X-Energy Matthew Marzano EPW (Senate.Gov)
ECHEN2 North Carolina State University Christopher Deloglos Unknown Sofia Guerra Unknown Carl Elks Unknown Hongbin Zhang Unknown Dana Lovelace Unknown James Watkins Unknown John Weglian Unknown Michelle Byman Unknown Neil Archambo Unknown Maggie Staiger Unknown Wiliiam Catullo Unknown Hyun Cook Kang (RPI) Unknown Phil Couture Unknown Frank Hope Unknown Pope Steven Unknown Roy Hardin Unknown Ken Scarola Unknown Sherry Wong Unknown Mike Bailey Unknown Jack Clark Unknown Tim Tully Unknown Hayden Kindell Unknown Gary Johnson Unknown Rick Hite Unknown Bob Hirmanpour Unknown Andy Nack Unknown 1
Unknown organization indicates that the participants affiliation was not provided by the issuance of this meeting summary.
ML22054A002 *by email OFFICE NRR/DORL/LPL4/PM* NRR/DORL/LPL4/LA* NRR/DEX/EICB/BC*
NAME BJain PBlechman MWaters DATE 2/23/2022 2/28/2022 3/9/2022`
OFFICE NRR/DEX/ELTB/BC* NRR/DORL/LPL4/PM*
NAME JJohnston BJain DATE 03/14/2022 3/14/2022