ML21309A034

Public Meeting Summary Reactor Pressure Vessel Embrittlement Monitoring and Prediction in Long-Term Operation

ML21309A034
Person / Time
Issue date:	11/10/2021
From:	Stewart Schneider NRC/NMSS/DREFS/RRPB
To:
Schneider, Stewart
References
20211318, NRC-2021-0174
Download: ML21309A034 (8)

Text

U.S. Nuclear Regulatory Commission Public Meeting Summary

November 10, 2021

Title:

Reactor Pressure Vessel Embrittlement Monitoring and Prediction in Long-Term Operation

Meeting Identifier: 20211318

Date of Meeting: October 18, 2021

Location: Webinar

Type of Meeting: Information Meeting with a Question and Answer Session

Purpose of the Meeting:

To provide an opportunity for the Nuclear Regulatory Commission (NRC) staff and external stakeholders to exchange information related to the embrittleme nt trend curve in Regulatory Guide 1.99, Rev. 2, Radiation Embrittlement of Reactor Vessel Materials, and 10 CFR 50.61, Fracture Toughness Requirements for Protection Against Pressur ized Thermal Shock Events, and surveillance requirements in Appendix H, Reactor Vessel Material Surveillance Program Requirements, to 10 CFR Part 50, Domestic Licensing of Produc tion and Utilization Facilities.

The NRC staff discussed analyses related to these topics and th e potential impact on the reactor pressure vessel during long-term operation.

General Details:

The NRC conducted a public meeting scheduled from 1:00 p.m. - 4:00 p.m. eastern time that ran approximately 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. The meeting was attended by 95 indi viduals, including 38 members of the NRC staff and 57 members of the public. All attendees p articipated via WebEx and teleconference. Meeting participants included nuclear power re actor licensees (e.g., Dominion Energy, Duke Energy, Florida Power & Light Company), representa tives from the nuclear industry (e.g., Electric Power Research Institute, Nuclear Ener gy Institute), other stakeholders (e.g., Florida Department of Health, Structural Integrity, Virg inia Department of Emergency Management), and private citizens. The meeting was transcribed, and the transcript is available in the NRCs Agencywide Document Access and Management System ( ADAMS) under Accession No. ML21309A057, and at Regulations.gov under Docket No. NRC-2021-0174.

A list of attendees is provided as an attachment to this meetin g summary.

Summary of NRC Presentation:

The meeting began with an NRC presentation related to the embri ttlement trend curve in Regulatory Guide 1.99, Rev. 2 and 10 CFR 50.61, and surveillanc e requirements in Appendix H to 10 CFR Part 50. The presentation was focused on continuing the discussions of issues from the May 2020 public meeting (ADAMS Accession No. ML20168A008), discussing a holistic risk-informed analysis of these issues and their potential impact on reactor pressure vessel (RPV) integrity. The NRC staff explained the issues of insufficient embrittlement monitoring and under predictions of RPV embrittlement in the current regulatory fram ework and how these issues may eventually impact the NRC staffs confidence in the integrity o f the RPV during long-term operation. The NRC staff provided potential options to address these issues and sought feedback on its risk-informed analysis approach and potential o ptions.

Following the NRC presentation, three members of the public pro vided a presentation or prepared remarks. First, the Electric Power Research Institute (EPRI) provided a presentation on industry initiatives that will help generate high fluence da ta. These industry initiatives included the Coordinated Reactor Vessel Surveillance Program an d the Pressurized Water Reactor Supplemental Surveillance Program. Second, Duke Energy provided prepared remarks related to the RPV material surveillance program at Rob inson Nuclear Plant. Finally, Beyond Nuclear provided prepared remarks about its concern rega rding the limited amount of time the public can participate in the NRC staffs review proce ss for Subsequent License Renewal Applications, especially when considering the issues id entified by the NRC staff in its presentation.

The NRC then opened the meeting for feedback and questions. Th e meeting concluded with a description of how to find more information at Regulations.gov and use of the NRC public meeting feedback form.

The meeting transcript, which provides the complete meeting dis cussions, is available in ADAMS under Accession No. ML21309A057. Also, the NRC and EPRI s presentation slides are available in ADAMS under Accession Nos. ML21270A002 and ML2 1288A145, respectively.

Public Participation Themes:

NRC staff addressed questions on the following topics:

• Question: A representative from Beyond Nuclear inquired about additional detail on EPRIs presentation and whether it relates to harvesting of dec ommissioning nuclear power stations and harvesting to investigate embrittlement from the outer wall of the RPV or welds due to neutron irradiation that bounce off the con crete containment.

NRC Response: The NRC is not familiar with the specifics about EPRIs industry initiative that the representative from Beyond Nuclear was inqu iring about. The NRC indicated that the neutron fluence of the RPVs from currently d ecommissioning plants are not in the range that have been identified as potential iss ues at present. Similarly, with respect to the statement about embrittlement from the oute r wall of the RPV, the NRC indicated that due to the neutron fluence of the RPVs from currently decommissioning plants, there would be little additional inform ation gained on this topic by harvesting samples from those plants.

• Question: A representative from the Nuclear Energy Institute (NEI) inquired whether the staff has enough information to assess these issues from a risk -informed approach or is more information needed from the risk community.

2 NRC Response: The NRC indicated that no additional information is needed from the risk community and that the information needs are associated with plant-specific details to address the uncertainties in the staffs risk-informed analy sis.

• Question: A representative from Xcel Energy inquired about sl ide 20 of the NRCs presentation, specifically implementation of the guidance in Re gulatory Guide 1.99, Rev. 2, related to assessing the credibility of surveillance ca psule data.

NRC Response: The NRC indicated the information in Regulatory Guide 1.99, Rev. 2, related to assessing the credibility of surveillance data does not require or recommend that the use the non-credible chemistry factor. The NRC indica ted that the goal of the surveillance program and use of the embrittlement trend curve i s to get the most accurate prediction of embrittlement, and that in certain scena rios the use of non-credible surveillance data may be appropriate in providing a mo re accurate representation.

• Question: A representative from Energy Northwest noted that t he NRCs presentation included discussions on weld and bases materials and inquired a bout heat affected zone material.

NRC Response: The NRC has indicated that it presented data tha t was part of the development of ASTM E900, Standard Guide for Predicting Radiat ion-Induced Transition Temperature Shift in Reactor Vessel Materials. Fur ther, the NRC indicated that the heat affected zone data is no longer required through Appendix H to 10 CFR Part 50.

• Question: A representative from Nuclear Energy Information Se rvice provided remarks regarding embrittlement of RPV from a nuclear power plant in Ja pan and inquired about the use of neutron fluence instead of time to predict neutron e mbrittlement.

NRC Response: The NRC indicated that it is not familiar with t he details of the referenced nuclear power plant in Japan and is unable to provid e further information.

With respect to the use of neutron fluence as a means to predic t neutron embrittlement, the NRC staff explained that neutron fluence is a measure of th e number of neutrons that have hit the RPV vessel and that correlates with the embri ttlement.

• Question: A representative of Dominion Energy inquired about the neutron fluence values in the NRCs presentation and whether these values refer to the surface fluence or the 1/4 thickness neutron fluence.

NRC Response: The NRC indicated that the neutron fluence level s in its presentation refers to the level at which the under prediction of the embrit tlement trend curve becomes statistically significant, no matter where it occurs th roughout the vessel wall.

Thus, if the assessment is for Pressure-Temperature Limit Curve s then the 1/4 thickness neutron fluence is applicable, and if the assessment is for Pre ssurized Thermal Shock then the inner-diameter surface neutron fluence is applicable.

Action Items/Next Steps:

• There were no action items as a result of the public meeting.

3 Additional Information:

• Meeting notice and agenda: ADAMS Accession No. ML21280A267

• NRC staff presentation: ADAMS Accession No. ML21270A002

• EPRI presentation: ADAMS Accession No. ML21288A145

• Transcript: ADAMS Accession No. ML21309A057

• Meeting Summary: ADAMS Accession No. ML21309A034

4 RPV EMBRITTLEMENT MONITORING AND PREDICTION IN LONG-TERM OPERATION

PUBLIC MEETING HELD ON 10/18/2021

CATEGORY: INFORMATION MEETING WITH A QUESTION AND ANSWER SESSION

LIST OF ATTENDEES

No. First Name Last Name Affiliation 1 Brian Allik NRC 2 Howard Benowitz NRC 3 Christopher Brown NRC 4 Angela Buford NRC 5 Scott Burnell NRC 6 Bob Caldwell NRC 7 Dave Dijamco NRC 8 Carolyn Fairbanks NRC 9 Lauren Gibson NRC 10 Allen Hiser NRC 11 Matthew Hiser NRC 12 Tanya Hood NRC 13 Raj Iyengar NRC 14 Joel Jenkins NRC 15 Audrey Klett NRC 16 Robert Krsek NRC 17 Glenna Lappert NRC 18 Louise Lund NRC 19 Bill Maier NRC 20 Carol Moyer NRC 21 Tony Nakanishi NRC 22 Caty Nolan NRC 23 Joan Olmstead NRC 24 John Pelchat NRC 25 Jeff Poehler NRC 26 Tim Reed NRC 27 Hector Rodriguez NRC 28 Bill Rogers NRC 29 David Rudland NRC 30 Stewart Schneider NRC 31 Fred Schofer NRC

5 RPV EMBRITTLEMENT MONITORING AND PREDICTION IN LONG-TERM OPERATION

PUBLIC MEETING HELD ON 10/18/2021

CATEGORY: INFORMATION MEETING WITH A QUESTION AND ANSWER SESSION

LIST OF ATTENDEES

No. First Name Last Name Affiliation 32 Neil Sheehan NRC 33 Robert Taylor NRC 34 Rob Tregoning NRC 35 John Tsao NRC 36 Shakur Walker NRC 37 Lynnea Wilkins NRC 38 On Yee NRC 39 Ronald Ballinger Advisory Committee On Reactor Safeguards 40 Haitham Shiblaq American Electric Power 41 Paul Gunter Beyond Nuclear 42 Jana Bergman Curtiss-Wright 43 Michael Guthrie Dominion Energy 44 Garrett Haltiwanger Dominion Energy 45 Beth Haluska Dominion Energy 46 Craig Heah Dominion Energy 47 James Hester Dominion Energy 48 Carl Rosenwald DTE Energy 49 Satira Labib Duke Energy 50 Rita Sipe Duke Energy 51 Joe Terrell Duke Energy 52 Tony Zimmerman Duke Energy 53 Bob Carter Electric Power Research Institute 54 Elliot Long Electric Power Research Institute 55 Wayne Lunceford Electric Power Research Institute 56 Nathan Palm Electric Power Research Institute 57 Steven Williams Electric Power Research Institute 58 Larry Hinkle Energy Harbor 59 Steve Richter Energy Northwest 60 Todd Sherman Entergy 61 Steve Skubey Evergy 62 Peter Tamburro Exelon

6 RPV EMBRITTLEMENT MONITORING AND PREDICTION IN LONG-TERM OPERATION

PUBLIC MEETING HELD ON 10/18/2021

CATEGORY: INFORMATION MEETING WITH A QUESTION AND ANSWER SESSION

LIST OF ATTENDEES

No. First Name Last Name Affiliation 63 Phillip Donaldson Florida Bureau of Radiation Control 64 Kevin Kunder Florida Bureau of Radiation Control 65 Donald Phillips Florida Bureau of Radiation Control 66 Michael Stephens Florida Bureau of Radiation Control 67 Kenneth Barnhart Florida Department of Health 68 Donald Phillips Florida Department of Health 69 Mark Seidensticker Florida Department of Health 70 Scott Boggs Florida Power & Light Company 71 Steve Franzone Florida Power & Light Company 72 Bill Maher Florida Power & Light Company 73 Basil Pagnozzi Florida Power & Light Company 74 Maribel Valdez Florida Power & Light Company 75 Mats Molin Forsmarks Kraftgrupp AB 76 Bette Pierman Michigan Safe Energy 77 Toni Hicks n/a 78 Beth Thompson n/a 79 Charles Tomes n/a 80 Devin Shiple Neal R. Gross and Company 81 Jan Boudart Nuclear Energy Information Service 82 Thomas Basso Nuclear Energy Institute 83 Johan Blomstroem Ringhals AB 84 Audrey Burross South Carolina Department of Health and Envir onmental Control 85 Anuradha Nair South Carolina Department of Health and Enviro nmental Control 86 Derrick Stanley South Carolina Department of Health and Envi ronmental Control 87 Daniel Denis Structural Integrity 88 Sam Ranganath Structural Integrity 89 Steve Dermer Virginia Department of Emergency Management 90 Brian Iverson Virginia Department of Emergency Management

7 RPV EMBRITTLEMENT MONITORING AND PREDICTION IN LONG-TERM OPERATION

PUBLIC MEETING HELD ON 10/18/2021

CATEGORY: INFORMATION MEETING WITH A QUESTION AND ANSWER SESSION

LIST OF ATTENDEES

No. First Name Last Name Affiliation 91 Stacie Neal Virginia Department of Emergency Management 92 Ed Porner Virginia Department of Emergency Management 93 Asfaw Fenta Virginia Department of Health 94 Christopher Koehler Xcel Energy 95 Russell Lidberg Xcel Energy

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